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ROADWAY DESIGN MANUALVersion 2.0 November 2014 ROADWAY DESIGN MANUAL Roadway Design Manual Version 2.0 – November 2014 Abu Dhabi City Municipality PO Box 263 Abu Dhabi, United Arab Emirates © Copyright 2014, Abu Dhabi City Municipality. All Rights Reserved. No part of this document may be reproduced, distributed, or transmitted in any form or by any means without the prior written permission of the Abu Dhabi City Municipality Version 2.0 November 2014 ROADWAY DESIGN MANUAL TABLE OF CONTENTS PART 1 – ROADWAY DEVELOPMENT SECTION 100 - GENERAL INFORMATION DESCRIPTION PAGE NO. 101 PURPOSE 100-1 101.01 INTRODUCTION 100-1 102 CONTENTS AND ORGANIZATION 100-3 102.01 PART 1 : ROADWAY DEVELOPMENT 100-3 102.02 PART 2 : ROADWAY DESIGN 100-3 102.03 PART 3 : STRUCTURE DESIGN 100-4 103 INTERIM ADVICE NOTES AND TECHNICAL CIRCULARS 100-4 103.01 GENERAL 100-4 103.02 INTERIM ADVICE NOTES AND TECHNCICAL CIRCULARS - GENERAL 100-4 103.03 INTERIM ADVICE NOTES AND TECHNCICAL CIRCULARS - SPECIFIC 100-4 104 ROADWAY CLASSIFICATIONS 100-5 104.01 ROADWAY SYSTEM 100-5 104.01.01 Rural Roadways 100-5 104.01.02 Urban Roadways 100-6 104.02 DESIGN 100-8 104.03 CRITERIA FOR DESIGN CLASS DESIGNATION 100-8 105 ROUTE DESIGNATIONS 100-10 SECTION 200 - DESIGN CONCEPT DEVELOPMENT DESCRIPTION PAGE NO. 201 TRANSPORTATION PLANNING 200-1 201.01 INTRODUCTION 200-1 201.02 INTERNAL ROADS AND INFRASTRUCTURE DIRECTORATE (IRID) 200-1 201.03 TOWN PLANNING SECTOR 200-1 201.04 MAPPING 200-1 201.04.01 General 200-2 201.04.02 Topographic Mapping 200-2 201.05 PROJECT LIMITS 200-4 201.06 PROJECT IDENTIFICATION AND NUMBERING 200-8 201.07 INTER-DEPARTMENTAL COORDINATION 200-8 Version 2.0 Part 0 – Table of Contents Page 1 of 18 November 2014 ROADWAY DESIGN MANUAL 202 ENVIRONMENTAL FACTORS INFLUENCING DESIGN 200-8 202.01 INTRODUCTION 200-8 202.02 SOCIO ECONOMIC/COMMUNITY RESOURCE DATA 200-9 202.02.01 Land Use 200-9 202.02.02 Growth Projections 200-10 202.02.03 Public Services 200-10 202.02.04 Schools 200-11 202.02.05 Mosques 200-13 202.02.06 Malls 200-13 202.02.07 Hospitals 200-13 202.02.08 Utilities 200-13 202.02.09 Security 200-14 202.02.10 Commercial Activities 200-15 202.02.11 Economics 200-15 202.02.12 Local Transportation/Circulation 200-15 202.02.13 Parking Requirements 200-15 202.02.14 Recreation 200-16 202.02.15 Historical Site Identification and Preservation 200-17 202.03 NATURAL/ENVIRONMENTAL RESOURCE DATA 200-17 202.03.01 Protection of Existing Amenities 200-17 202.03.02 Topography 200-18 202.03.03 Water 200-19 202.03.04 Flora and Fauna 200-19 202.03.05 Air Quality 200-19 202.03.06 Noise 200-19 202.03.07 Visual/Aesthetic 200-19 202.03.08 Hazardous Materials 200-19 202.04 ENVIRONMENTAL PERMIT 200-20 203 TECHNICAL INVESTIGATIONS 200-20 203.01 INTRODUCTION 200-20 203.02 GEOTECHNICAL 200-20 203.03 TRAFFIC DATA COLLECTION 200-21 203.03.01 Introduction 200-21 203.03.02 Traffic Projections 200-21 203.03.03 Procedures for Collecting Traffic Volumes 200-22 203.03.03.01 Automatic Traffic Counts 200-22 203.03.03.02 Classified Turning Movement Counts 200-22 203.03.03.03 Automatic Speed Surveys 200-23 Version 2.0 Part 0 – Table of Contents Page 2 of 18 November 2014 ROADWAY DESIGN MANUAL 203.03.03.04 Other Surveys 200-23 203.04 SURVEY CONTROL/FIELD SURVEYS 200-24 203.04.01 Introduction 200-24 203.04.02 Horizontal Control 200-24 203.04.03 Vertical Control 200-24 203.04.04 Coordinate System 200-24 203.04.05 Field Surveys 200-25 203.05 DRAINAGE SURVEYS 200-25 SECTION 300 - DESIGN CONCEPT REPORT DESCRIPTION PAGE NO. 301 CONTENTS 300-1 301.01 FORMAT 300-3 302 EXECUTIVE SUMMARY 300-6 303 INTRODUCTION 300-6 304 TRAFFIC ANALYSIS 300-6 305 DESCRIPTION OF ALTERNATIVES 300-7 306 DESIGN DATA 300-8 307 TYPICAL SECTIONS 300-9 308 GEOMETRICS 300-9 309 INTERCHANGE/INTERSECTION CONFIGURATION 300-9 310 PARKING STUDY 300-10 311 HYDROLOGY AND HYDRAULICS 300-10 312 SUBSURFACE INVESTIGATIONS 300-11 313 BRIDGE TYPE SELECTION 300-12 313.01 BRIDGES OVER WATERWAYS 300-13 313.02 WIDENINGS/REHABILITATION 300-13 313.03 BRIDGES AND HIGHWAY STRUCTURES CONCEPT REPORT 300-14 314 TUNNEL SELECTION CRITERIA 300-15 315 UTILITY IMPACT ANALYSIS 300-16 316 SOCIO - ECONOMIC ANALYSIS 300-17 317 AGRICULTURE IMPACT 300-17 318 PUBLIC FEEDBACK 300-18 319 SIGNING AND PAVEMENT MARKINGS 300-18 320 LIGHTING CONCEPTS 300-19 321 CONSTRUCTION STAGING 300-19 322 COST ESTIMATE 300-19 Version 2.0 Part 0 – Table of Contents Page 3 of 18 November 2014 ROADWAY DESIGN MANUAL 323 CONCLUSIONS/RECOMMENDATIONS 300-21 324 APPENDIX 300-21 325 DRAWINGS 300-21 Version 2.0 Part 0 – Table of Contents Page 4 of 18 November 2014 ROADWAY DESIGN MANUAL TABLE OF CONTENTS PART 2 – ROADWAY DESIGN SECTION 100 - GENERAL DESIGN CRITERIA DESCRIPTION PAGE NO. 101 DESIGN SPEED 100-1 102 DESIGN VEHICLES 100-2 103 DESIGN TRAFFIC 100-3 103.01 DESIGN PERIOD 100-3 103.02 RELATION TO DESIGN 100-3 104 ROADWAY CAPACITY 100-4 104.01 DESIGN CAPACITIES (VEHICLES) 100-4 104.01.01 Introduction 100-4 104.01.02 LOS Definitions for Urban Roads 100-4 104.01.03 LOS Definitions for Freeway and Multi-Lane Roads 100-5 104.01.04 LOS Definitions for Merge/Diverge and Weaving Sections 100-5 104.01.05 LOS Definitions for Signalised Intersections 100-6 104.01.06 LOS Definitions for Priority Intersections and Roundabouts 100-7 104.01.07 LOS Definitions at Cycle Facilities 100-7 104.01.08 LOS Definitions for Pedestrian Facilities 100-8 104.01.09 LOS Definitions and Standards for Public Transportation Services 100-9 105 CONTROL OF ACCESS 100-9 105.01 GENERAL 100-9 105.02 ACCESS CONTROL DESIGN CRITERIA 100-10 105.02.01 Primary Roadways 100-10 105.02.02 Secondary Roadways (ADT > 2,500) 100-11 105.02.03 Secondary Roadways (ADT < 2,500) 100-11 105.03 USE OF FRONTAGE ROADS 100-12 105.04 PROTECTION OF ACCESS RIGHTS 100-13 105.04.01 Relation of Access Opening to a Median Opening 100-13 105.05 MAINTAINING LOCAL COMMUNITY ACCESS 100-13 105.06 PEDESTRIAN FACILITIES 100-13 105.06.01 General Policy 100-13 105.06.02 Sidewalks and Walkways 100-14 105.07 PEDESTRIAN GRADE SEPARATIONS 100-15 105.08 GUIDELINES FOR THE LOCATION AND DESIGN OF KERB RAMPS 100-15 106 DEPARTURES FROM STANDARDS Version 2.0 100-15 Part 0 – Table of Contents Page 5 of 18 November 2014 05 LONG SUSTAINED GRADES 200-19 204.01 GENERAL 200-13 203.02 SPECIAL BICYCLE FACILITIES 100-19 108.0 Part 0 – Table of Contents Page 6 of 18 November 2014 .03 STANDARDS FOR GRADES 200-15 204. GUIDELINES AND REFERENCES 100-20 SECTION 200 .04 VERTICAL CURVES 200-16 204.04 SUPERELEVATION TRANSITION 200-8 202.02 TRANSITIONS FOR MULTI-LANE ROADWAYS 200-21 Version 2.05 DECISION SIGHT DISTANCE 200-3 202 SUPERELEVATION 200-4 202.02 PASSING SIGHT DISTANCE 200-1 201.01 GENERAL 200-4 202.01 GENERAL 200-14 204.02 SUPERELEVATION STANDARDS 200-5 202.02 VERTICAL ALIGNMENT POSITION WITH RESPECT TO CROSS SECTION 200-15 204.01 GENERAL 100-18 108.03 STOPPING SIGHT DISTANCE 200-2 201.04 STOPPING SIGHT DISTANCE ON HORIZONTAL CURVES 200-3 201.04 BICYCLES AT INTERSECTIONS 100-20 109 ADDITIONAL STANDARDS.06 STRUCTURE GRADE LINE 200-20 204.01 GENERAL 200-1 201.01 GENERAL 200-21 206.03 BICYCLE CHARACTERISTICS 100-20 108.ROADWAY DESIGN MANUAL 107 ROAD SAFETY AUDITS 100-18 108 BICYCLE FACILITIES 100-18 108.GEOMETRIC DESIGN STANDARDS DESCRIPTION PAGE NO.07 SEPARATE PROFILE GRADE LINES 200-20 205 COORDINATION OF HORIZONTAL AND VERTICAL ALIGNMENTS 200-20 206 PAVEMENT TRANSITIONS 200-21 206. 201 SIGHT DISTANCE 200-1 201.03 AXIS OF ROTATION 200-8 202.05 SUPERELEVATION OF COMPOUND CURVES 200-12 203 HORIZONTAL ALIGNMENT 200-13 203.02 STANDARDS FOR HORIZONTAL CURVATURE 200-13 204 VERTICAL ALIGNMENT 200-14 204. 01 BUS STOPS 200-28 210.02 TYPES AND USES 200-27 209.02 TAXI STOPS 200-29 211 PARKING 200-29 211.02 PEDESTRIAN GRADE SEPARATIONS 200-25 208.01 GENERAL 200-29 211.01 SIDE SLOPE VALUES 300-3 303.01 SIDEWALKS 200-23 208.02 SLOPE CLEARANCE FROM RIGHT OF WAY 300-3 304 MEDIAN STANDARDS 300-4 305 HORIZONTAL AND VERTICAL CLEARANCES 300-4 305.01 SHOULDER WIDTH STANDARDS 300-1 302. 301 TRAVELLED WAY STANDARDS 300-1 301.03 TRAVELLED WAY PAVEMENT TYPE 300-1 302 SHOULDER STANDARDS 300-1 302.ROADWAY DESIGN MANUAL 207 BRIDGES AND GRADE SEPARATION STRUCTURES 200-22 207.02 PARKING AREAS 200-30 211.02 CROSS SLOPE 200-23 208 PEDESTRIAN FACILITIES 200-23 208.04 CYCLE TRACKS 200-25 209 KERBS 200-27 209.03 ON STREET PARKING SPACES 200-31 211.04 PARKING LOTS 200-31 211.02 SHOULDER CROSS SLOPES 300-2 303 SIDE SLOPE STANDARDS 300-3 303.03 PEDESTRIAN UNDERPASSES 200-25 208.05 PARKING DEMAND/SUPPLY ANALYSIS 200-31 SECTION 300 .0 300-4 Part 0 – Table of Contents Page 7 of 18 November 2014 .01 CLEAR WIDTH 200-22 207.03 KERB PARAMETERS 200-28 210 BUS STOPS AND TAXI STOPS 200-28 210.01 TRAVELLED WAY WIDTH 300-1 301.01 GENERAL 200-27 209.02 TRAVELLED WAY CROSS SLOPES 300-1 301.GEOMETRIC CROSS SECTIONS DESCRIPTION PAGE NO.01 HORIZONTAL CLEARANCES Version 2. 01 APPLICATION OF CLEAR ZONE 300-9 306.08 TESTING AND FUTURE MAINTENANCE 308 REFERENCES 300-32 300-33 SECTION 400 .01 Roadside Terrain: Foreslope 300-9 306.01 Median Barrier Warrants 300-26 307.01.05.03 INTERSECTION ANGLES 400-6 404.AT GRADE INTERSECTIONS (JUNCTIONS) DESCRIPTION PAGE NO.01 BARRIER NEED 300-13 307.02 Effects of Roadside Terrain 300-21 307.01 PREFERENCE TO MAJOR MOVEMENTS 400-6 404.05 SPEED-CHANGE LANES 400-7 Version 2.03 Roadside Terrain: Cross Slope 300-10 306.04 Roadside Terrain: Ditch 300-10 307 BARRIERS 300-13 307.02 Crash Cushions 300-29 307.07.01 Lateral Placement 300-20 307.02 AREAS OF CONFLICT 400-6 404.04 POINTS OF CONFLICT 400-7 404.03 ROADSIDE BARRIER TYPES AND FEATURES 300-16 307.02 Roadside Terrain: Backslope 300-10 306.01.07 END TREATMENTS AND CRASH CUSHIONS 300-29 307.04.06 MEDIAN BARRIER PLACEMENT 300-28 307.0 Part 0 – Table of Contents Page 8 of 18 November 2014 .02 Median Barrier Types and Features 300-26 307.04.01 End Treatments 300-29 307.01.05 MEDIAN BARRIERS 300-26 307.05.04 ROADSIDE BARRIER PLACEMENT 300-20 307.04.03 TUNNEL CLEARANCES 300-5 306 CLEAR ZONE CONCEPTS 300-5 306.03 Barrier Length Design 300-22 307.01.ROADWAY DESIGN MANUAL 305.07. 401 GENERAL 400-1 402 DESIGN CONSIDERATIONS 400-1 403 AT GRADE INTERSECTION TYPES 400-1 404 CHANNELIZATION 400-5 404.02 BARRIER DESIGN 300-14 307.02 VERTICAL CLEARANCES 300-4 305. 02 FOUR-LEG INTERCHANGES 500-4 505 INTERCHANGE DESIGN PROCEDURES 500-17 506 INTERCHANGE DESIGN STANDARDS 500-17 507 RAMP DESIGN STANDARDS 500-21 508 ENTRANCE/EXIT RAMP DESIGN STANDARDS 500-25 509 RAMP TERMINAL DESIGN 500-32 Version 2.10 INSTALLATION OF TRAFFIC CONTROL DEVICES 400-8 404.06 TURNING MOVEMENTS 400-7 404.07 TRAFFIC ISLANDS 400-27 407 ROUNDABOUT DESIGN 400-27 407.01 GENERAL 400-27 407.02 INTERSECTION CONTROL 400-17 406.09 EFFECTIVE SIGNAL CONTROL 400-7 404.ROADWAY DESIGN MANUAL 404.02 LOCATION OF ROUNDABOUTS 400-32 407.04 EFFECT OF VERTICAL PROFILES 400-25 406.01 THREE-LEG INTERCHANGES 500-2 504.11 GUIDELINES 400-8 405 DESIGN VEHICLES 400-8 405.05 LEFT-TURN CHANNELIZATION 400-25 406.08 PROHIBITED TURNS 400-7 404.01 SWEPT PATH ANALYSIS 400-8 405.0 Part 0 – Table of Contents Page 9 of 18 November 2014 .03 ROUNDABOUT SELECTION 400-33 SECTION 500 .03 EFFECT OF SKEW 400-24 406.02 DESIGN VEHICLES 400-8 406 INTERSECTION DESIGN STANDARDS 400-12 406.06 RIGHT-TURN CHANNELIZATION 400-26 406.07 REFUGE AREAS 400-7 404. 501 GENERAL 500-1 502 INTERCHANGE WARRANTS 500-1 503 DESIGN CONSIDERATIONS 500-1 504 INTERCHANGE TYPES 500-2 504.01 SIGHT DISTANCE 400-12 406.GRADE SEPARATED INTERCHANGES DESCRIPTION PAGE NO. 02 DESIGN REQUIREMENTS 600-1 602.03 PAVEMENT DESIGN METHOD .04 PAVEMENT DESIGN REPORT 600-11 602.04 Large-Scale Laboratory Testing 600-19 603.DRAINAGE DESCRIPTION PAGE NO.01 GENERAL 800-4 804.05 QUALITY ASSURANCE .02 UTILITY PROTECTION 800-5 804.01 INTRODUCTION 600-15 603.03.UTILITIES DESCRIPTION PAGE NO.04 REFERENCES 600-23 SECTION 700 .03 Full-Scale Independent Accelerated Pavement Testing (FS/APT) 600-18 603.01 GENERAL 600-1 602.03.ROADWAY DESIGN MANUAL SECTION 600 .06 Independent Review and Validation 600-22 603.03.05 Acceptance Criteria of Pavement Design 600-19 603.02 Full-Scale Accelerated Pavement Testing 600-18 603.03 ACCEPTANCE CRITERIA 600-17 603.PAVEMENT DESIGN 600-13 603 ADM ACCEPTANCE CRITERIA FOR MECHANICALLY STABILIZED FLEXIBLE PAVEMENTS USING GEOGRIDS 600-15 603.02 DEFINITIONS AND TERMINOLOGY 600-16 603.01 Verification of Material Characteristics 600-18 603.STRUCTURAL PAVEMENT DESIGN DESCRIPTION PAGE NO.03 UTILITY RELOCATION 800-5 Version 2.0 Part 0 – Table of Contents Page 10 of 18 November 2014 . 601 INTRODUCTION 600-1 602 STRUCTURAL PAVEMENT SECTION DESIGN 600-1 602.03. 701 GENERAL 700-1 SECTION 800 .03.03. 801 GENERAL 800-1 802 UTILITY PLANNING 800-2 803 SERVICE RESERVATIONS 800-3 804 UTILITY DESIGN 800-4 804.EMPIRICAL 600-2 602. 01 GENERAL 1000-6 1003.0 Part 0 – Table of Contents Page 11 of 18 November 2014 .04 LANTERN SELECTION 1000-6 1003 SIDEWALK LIGHTING 1000-6 1003.02 LIGHTING CONTROLLER REQUIREMENTS 1000-6 1004.03 LANTERN MOUNTING HEIGHT 1000-5 1002.ROADWAY DESIGN MANUAL 804.03 DESIGN STANDARDS AND PROCEDURES 1000-7 1005 POWER DISTRIBUTION 1000-7 1006 DESIGN AND SUPERVISION RESPONSIBILITIES 1000-8 1007 DESIGN REQUIREMENTS 1000-8 1007.05 UTILITY LOCATIONS 800-6 804.06 NON-DISRUPTIVE ROAD CROSSINGS 800-6 SECTION 900 .03 DETAILED DESIGN 1000-9 Version 2. 1001 ROADWAY LIGHTING 1000-1 1001.01 CONCEPT DESIGN 1000-8 1007.04 CONTINGENCY DUCTS 800-6 804.03 ILLUMINATION REQUIREMENTS 1000-4 1002 PARKING AREA LIGHTING 1000-5 1002.04 LANTERN SELECTION 1000-6 1004 LIGHTING CONTROLS 1000-6 1004.01 GENERAL 1000-1 1001.02 ILLUMINATION REQUIREMENTS 1000-6 1003.TRAFFIC ENGINEERING DESCRIPTION PAGE NO.02 ILLUMINATION REQUIREMENTS 1000-5 1002.LIGHTING DESCRIPTION PAGE NO.01 GENERAL 1000-5 1002.01 GENERAL 1000-6 1004.02 LIGHTING DESIGN CONSIDERATIONS 1000-2 1001.03 LANTERN MOUNTING HEIGHT 1000-6 1003.02 PRELIMINARY DESIGN 1000-9 1007. 901 GENERAL 900-1 SECTION 1000 . ROADSIDE DEVELOPMENT DESCRIPTION PAGE NO.0 1100-3 Part 0 – Table of Contents Page 12 of 18 November 2014 .03 BUS SHELTERS 1100-3 1107 NOISE ABATEMENT Version 2.02 BENCHES 1100-3 1106.01 IRRIGATION DUCTS 1100-1 1103 FENCING 1100-2 1104 SLOPE PAVING 1100-2 1105 SWEET SAND COVERING 1100-2 1106 STREET FURNITURE 1100-2 1106.01 GENERAL 1100-2 1106.ROADWAY DESIGN MANUAL SECTION 1100 . 1101 LANDSCAPING 1100-1 1102 IRRIGATION 1100-1 1102. 02 ROADWAY DETAILS 100-8 102.DESIGN CRITERIA DESCRIPTION PAGE NO.01 GENERAL 100-8 102.15 CORROSION PROTECTION 100-12 102.12 BRIDGE DECK ELEVATIONS 100-11 102. 101 INTRODUCTION 100-1 101.13 CONCRETE CRACK CONTROL 100-11 102.08 ANCHOR SLABS 100-10 102.16 SPECIAL PROTECTIVE COATING 100-12 103 ARCHITECTURAL CONSIDERATIONS 100-12 104 SERVICE LIFE 100-12 105 DEFORMATION 100-12 Version 2.09 DECK DRAINAGE 100-10 102.ROADWAY DESIGN MANUAL TABLE OF CONTENTS PART 3 – STRUCTURE DESIGN SECTION 100 . PARAPETS AND RAILINGS 100-9 102.05 VALUE ENGINEERING AND SUSTAINABILITY 100-6 101.01 PURPOSE 100-1 101.04 WIDTH AND SPAN 100-8 102.02 DEFINITIONS 100-2 101.11 LIGHTING 100-10 102.06 GENERAL PROVISIONS 100-7 102 DESIGN FEATURES 100-8 102.03 CLEARANCE AT STRUCTURES 100-8 102.14 EARLY THERMAL CRACKING 100-11 102.0 Part 0 – Table of Contents Page 13 of 18 November 2014 .06 CONCRETE BARRIER TRANSITIONS 100-9 102.04 QUALITY ASSURANCE 100-3 101.05 TRAFFIC BARRIERS.07 APPROACH SLABS 100-9 102.03 BRIDGE TYPES 100-3 101.10 WING WALLS 100-10 102. 01 GENERAL 400-1 401.12 EARTHQUAKES 200-5 201.09 STREAM FORCES 200-4 201.14 OTHER LOADS 200-5 SECTION 300 .07 FRICTION FORCES 200-4 201.10 LATERAL EARTH PRESSURE 200-4 201.02 ALLOWABLE STRESSES IN PRE-STRESSED CONCRETE MEMBERS 400-1 402 PRECAST PRE-STRESSED CONCRETE Version 2.11 DIFFERENTIAL SETTLEMENT 200-5 201.ROADWAY DESIGN MANUAL SECTION 200 .05 FOOTWAY OR PEDESTRIAN LIVE LOAD 200-3 201.01 GENERAL 200-1 201.02 MINIMUM CONCRETE COVERS 300-2 301.08 THERMAL FORCES 200-4 201. 301 GENERAL 300-1 301. 401 DESIGN CRITERIA 400-1 401.REINFORCED CONCRETE DESCRIPTION PAGE NO.06 WIND LOAD 200-3 201.0 Part 0 – Table of Contents Page 14 of 18 400-2 November 2014 .01 CONCRETE 300-1 301.13 BUOYANCY AND HYDROSTATIC PRESSURE 200-5 201.02 DEAD LOADS 200-1 201.03 DESIGN METHODS 300-3 301.PRE-STRESSED AND POST-TENSIONED CONCRETE DESCRIPTION PAGE NO. 201 LOAD TYPES 200-1 201.DESIGN LOADS DESCRIPTION PAGE NO.03 WEARING SURFACE 200-1 201.04 REINFORCEMENT 300-3 302 SLAB DESIGN 300-3 303 WATERPROOFING 300-4 304 SURFACE FINISH 300-4 SECTION 400 .04 VEHICULAR LIVE LOADS 200-2 201. 09 ALLOWABLE STRESSES – CONCRETE 400-6 404.02 I – GIRDER BRIDGES 400-3 403.07 DEFLECTIONS 400-5 404.STRUCTURAL STEEL DESCRIPTION PAGE NO.12 FLANGE REINFORCEMENT 400-6 SECTION 500 .04 LOSS OF PRE-STRESS 400-3 403 PRE-STRESSED I – GIRDERS.03 MATERIALS 500-1 501. VOIDED SLABS AND BOX BEAMS 400-3 403.04 CREEP AND SHRINKAGE 400-5 404.05 LATERAL TIES 400-4 403.03 ALLOWABLE STRESSES .01 GENERAL 400-4 404.06 SHEAR KEYS 400-4 403.05 FLANGE AND WEB THICKNESS – BOX GIRDERS 400-5 404.06 CHARPY V-NOTCH IMPACT REQUIREMENTS 500-1 Version 2.01 DEFLECTIONS 400-2 402.01 GENERAL 400-3 403.11 FLEXURAL STRENGTH 400-6 404.04 INTERMEDIATE DIAPHRAGMS 400-3 403.02 GROUT 400-4 404.0 Part 0 – Table of Contents Page 15 of 18 November 2014 .10 LOSS OF PRE-STRESS 400-6 404.CONCRETE 400-2 402.03 DUCTS 400-5 404.02 ALLOWABLE STRESSES – PRE-STRESSING STEEL 400-2 402. 501 DESIGN CRITERIA 500-1 501.01 GENERAL 500-1 501.08 ALLOWABLE STRESSES – PRE-STRESSING STEEL 400-5 404.07 BARRIERS 400-4 404 POST-TENSIONED BOX GIRDER BRIDGES 400-4 404.ROADWAY DESIGN MANUAL 402.06 DIAPHRAGMS 400-5 404.03 END BLOCKS 400-3 403.02 DESIGN METHODS 500-1 501. 04 STEEL BEARINGS 600-5 603.01 GENERAL 700-1 701.05 OTHER JOINTS 600-3 603 BEARINGS 600-3 603.05 INTERNAL SHEAR KEYS 600-10 604.01 GENERAL 600-9 604.03 Use 600-7 603.02 VERTICAL FIXED RESTRAINERS 600-10 604.06.05 SLIDING ELASTOMERIC BEARINGS 600-5 603.02 GEOTECHNICAL REPORTING 700-1 702 GEOTECHNICAL DESIGN Version 2. 601 MOVEMENT CRITERIA 600-1 601.06 HIGH-LOAD MULTI-ROTATIONAL BEARINGS 600-6 603.03 ELASTOMERIC EXPANSION JOINTS 600-3 602.07 BEARING SCHEDULE 600-9 604 RESTRAINING DEVICES 600-9 604.ROADWAY DESIGN MANUAL SECTION 600 .06 KEYED HINGES 600-10 SECTION 700 .02 Rotational Requirements 600-6 603.0 700-3 Part 0 – Table of Contents Page 16 of 18 November 2014 .01 GENERAL 600-1 602.04 Design Criteria 600-7 603.02 STRIP SEALS 600-3 602.06.EXPANSION AND CONTRACTION DESCRIPTION PAGE NO.06.02 NEOPRENE STRIPS 600-4 603.06.01 MOVEMENT RATING 600-1 602 DECK JOINTS 600-1 602. 701 GROUND INVESTIGATION FOR GEOTECHNICAL WORKS 700-1 701.04 MODULAR JOINTS 600-3 602.GEOTECHNICAL DESCRIPTION PAGE NO.04 EXTERNAL SHEAR KEYS 600-10 604.03 ELASTOMERIC BEARING PADS 600-4 603.03 VERTICAL EXPANSION RESTRAINERS 600-10 604.01 Description 600-6 603.01 GENERAL 600-3 603. 801 DESIGN CRITERIA 800-1 801.03.01 Roadway Design Team 800-2 801.06 Bored Piles 700-6 701.01 GENERAL 800-1 801.05 VERTICAL CLEARANCE 900-3 903.0 Part 0 – Table of Contents Page 17 of 18 November 2014 .03.01.01.05 Driven Piles 700-6 701.02 Geotechnical Team 800-3 801.02 Design of Foundations 700-4 702.RETAINING WALLS DESCRIPTION PAGE NO.07 TRAFFIC BARRIERS AND RAILINGS 900-3 Version 2.01 FOUNDATIONS 700-3 702.02 TYPE OF STRUCTURE 800-2 801.06 DEFLECTION 900-3 903.03 Bridge Design Team 800-3 801.04 WIDTH 900-2 903.03 RESPONSIBILITIES 800-2 801.01 TYPE OF STRUCTURE 900-2 903.03 DESIGN LIFE 900-2 903.02 PEDESTRIAN LIVE LOAD 900-1 902.02 METHOD OF CONSTRUCTION 900-2 903.07 Micropiles 700-7 SECTION 800 .01 General 700-3 702.03 WIND LOAD 900-1 902.01.03 Spread (Strip) Footings 700-4 701.01.04 PROPRIETARY RETAINING WALLS 800-3 SECTION 900 – PEDESTRIAN BRIDGES DESCRIPTION PAGE NO.03.01.01. 901 DESIGN CRITERIA 900-1 902 LOAD TYPES 900-1 902.01.01 GENERAL 900-1 902.04 Pile Foundations 700-5 701.ROADWAY DESIGN MANUAL 702.04 OTHER LOADS 900-1 903 DESIGN CRITERIA 900-2 903. 02 FALSEWORK USE 1000-3 1003. 1001 TRAFFIC SIGN STRUCTURAL SUPPORTS 1000-1 1002 UTILITIES IN STRUCTURES 1000-1 1002.01 GENERAL 1000-4 1004.01 GENERAL 1000-1 1002.03 BRIDGE DESIGN TEAM RESPONSIBILITIES 1000-2 1003 FALSEWORK POLICY FOR BRIDGE CONSTRUCTION 1000-2 1003.11 PROTECTIVE COATING 900-3 903.REFERENCES DESCRIPTION PAGE NO.12 INSPECTION AND MAINTENANCE 900-4 SECTION 1000 .10 LIFTS AND STAIRS 900-3 903.03 PRECAST CONCRETE GIRDER BRIDGES 1000-5 1004.04 STEEL GIRDER BRIDGES 1000-6 1004.02 LONGITUDINAL CONSTRUCTION JOINTS 1000-5 1004.08 LIGHTING 900-3 903.0 Part 0 – Table of Contents Page 18 of 18 November 2014 .01 FALSEWORK REQUIREMENTS 1000-2 1003.ROADWAY DESIGN MANUAL 903. 1100 REFERENCES 1100-1 1101 REFERENCES FOR PART 3 – STRUCTURE DESIGN 1100-1 Version 2.09 DRAINAGE 900-3 903.03 FALSEWORK CLEARANCES 1000-3 1004 CONSTRUCTION JOINT GUIDELINES FOR BRIDGE CONSTRUCTION 1000-4 1004.01 CONSULTANT 1000-6 1005.05 CAST-IN-PLACE BOX GIRDER BRIDGES 1000-6 1005 RESPONSIBILITIES 1000-6 1005.02 GENERAL POLICY 1000-1 1002.MISCELLANEOUS DESCRIPTION PAGE NO.02 CONTRACTOR 1000-7 SECTION 1100 . 0 Part 0 – Divider November 2014 .ROADWAY DESIGN MANUAL PART 1 – ROADWAY DEVELOPMENT Version 2. ROADWAY DESIGN MANUAL SECTION 100 : GENERAL INFORMATION Version 2.0 Part 0 – Divider November 2014 . It is assumed that the user has the educational and engineering experience necessary to properly implement its procedures.  Plans will have a consistent. the standardization of the planning. The companion documents to this manual are:  Consultant Procedure Manual (2014)  Standard Drawings (2014)  Traffic Control Devices Manual (2014)  Standard Specifications (2014) This Manual supersedes the previous version of the ADM “Roadway Design Manual – Roads and Bridges” issued in 1998.  Cost efficiencies will be realized during design by an early understanding of procedures and criteria to be employed. design and construction of roadway projects will be complete.01 INTRODUCTION This Manual is intended to serve as a guide for the design of urban streets that fall under the jurisdiction of Abu Dhabi City Municipality (also referred to throughout this document as “ADM”).ROADWAY DESIGN MANUAL PART 1 .GENERAL INFORMATION 101 PURPOSE 101. which will not vary greatly from project to project.ROADWAY DEVELOPMENT SECTION 100 . It is expected that this manual will promote the following:  All designs will be based on identical criteria. well-organized format. and also refers to other stakeholder requirements that need to be taken into consideration during project development. guidelines and criteria. The Manual provides design guidance that will assist Consultants conform to the expectations of the Internal Roads and Infrastructure Directorate (IRID) of ADM. Reference manuals issued by other stakeholders will also need to be taken into consideration during the design process.  The technical review process will be expedited for both ADM and the Consultant. This manual utilizes established analysis techniques and design standards from recognized technical associations that are listed as references in the relevant sections. Version 2.0 Part 1 – Section 100 Page 1 of 10 November 2014 . When the Roadway Design Manual is combined with the four companion documents listed below. Version 2.0 Part 1 – Section 100 Page 2 of 10 November 2014 . Section 103 contains information regarding Interim Advice Notes and Technical Circulars. Note that where the Consultant's scope of work and this manual conflict.ROADWAY DESIGN MANUAL Examples of these documents are listed below:  Department of Municipal Affairs (DMA) Roadway & Public Realm Lighting Specification and Roadway Project Compliance Checklist Tables (2011)  DMA Urban Work Zone Traffic Management Manual  ADM Materials Selection Strategy  ADM Sustainability Guideline for ADM. Further contained in this section is an overview of the layout of the manual content.Consultant to liaise with the Parks & Recreation Facilities Division (PRFD)  ADM Emirate of Abu Dhabi Road Safety Audit Manual  Urban Planning Council (UPC) Urban Street Design Manual (USDM)  UPC Public Realm Design Manual (PRDM)  UPC Abu Dhabi Safety and Security Planning Manual (SSPM)  UPC Abu Dhabi Utility Corridors Design Manual (UCDM)  Abu Dhabi Department of Transport (DoT) Abu Dhabi Walking and Cycling Master Plan (WCMP)  DoT Trip Generation and Parking Rates Manual for the Emirate of Abu Dhabi  DoT Public Transit Strategy/Metro. the scope of work shall govern. Revisions and additions to this manual will be issued from time to time as required. IRI Employees and Consultants  ADM Drainage Design – Consultant to liaise with IRID Design Section  ADM Design Standards for Irrigation . roadway classifications and route designations. LRT and Bus Master Plans  DoT Abu Dhabi Manual of Uniform Traffic Control Devices  DoT Route Numbering System – Policy and Procedures  DoT Technical Circulars The above list is not considered to be exhaustive and the design consultant should ensure that the latest version of all relevant design documentation is used. which will be used to advise of future revisions and additions. the Design Concept Development and the Design Concept Report. The information is divided into eleven sections that include General Design Criteria. The Roadway Development part is divided into three sections. each with appropriate sub-sections.ROADWAY DESIGN MANUAL 102 CONTENTS AND ORGANIZATION The scope of the Roadway Design Manual is comprehensive and is divided into three parts. Structural Pavement Design.01 PART 1 : ROADWAY DEVELOPMENT The purpose of the Roadway Development part is to outline the information and data which must be analyzed to determine a project’s scope. procurement of information from both ADM and external parties is required. The three parts are as follows:  Part 1 : Roadway Development  Part 2 : Roadway Design  Part 3 : Structure Design 102. When used in conjunction with the ADM Standard Specifications and ADM Standard Drawings. Environmental Factors Influencing Design and Technical Investigations. Specifically. The project design is based on these standards. define the conceptual design of the project. Lighting and Roadside Development. Conceptual Design must be based upon site specific community considerations that reflect military. The first section explains the formal organization of this manual and the other two sections. To support the land’s intended use. Geometric Design Standards. Geometric Cross Sections. The Design Concept section includes subsections in Transportation Planning. a summary of the technical analyses and schematic designs that are to be used for plan preparation and construction. which becomes the basis for the project design. Utilities. Traffic Engineering. the resulting project plans and specifications for all projects are completed to the same requirements and format. physical properties of the site and circulation that define the project design. the Roadway Design part provides details in geometric design standards for each component of the roadway project. 102. environmental features. utility.0 Part 1 – Section 100 Page 3 of 10 November 2014 . The information and analyses are assembled into a Design Concept Report. At Grade Intersections (Junctions). All the collected project-specific data forms the basis for the Design Concept Report. The three parts are further divided into sections. Version 2. Drainage. Grade Separated Interchanges.02 PART 2 : ROADWAY DESIGN The purpose of the Roadway Design part is to identify the design standards that all roadway projects are required to satisfy. Reinforced Concrete. Uniform design and construction of structures and bridges promotes efficiency of design. Examples are revisions or refinements to policies. guidelines or criteria. They are also used to provide advance directives with respect to imminent revision or additions to the Roadway Design Manual. ADM or his designated representative. The tenth section addresses miscellaneous items such as traffic sign structural supports. Version 2.01 GENERAL This manual may be supplemented from time to time with Interim Advice Notes and Technical Circulars addressed to Consultants for the purpose of transmitting and formalizing appropriate revisions or additions to the manual. The last section provides a list of reference documents applicable to Part 3.ROADWAY DESIGN MANUAL 102. 103 INTERIM ADVICE NOTES AND TECHNICAL CIRCULARS 103. Design Loads. deal with issues or information that must be distributed on a system-wide basis to all consultants. Sections include Design Criteria. 103. This part focuses on features incorporating sound design and costeffective design practices to meet this goal.General. deal with issues or information that is of specific interest to a particular section (design contract). Pre-Stressed and Post-Tensioned Concrete.0 Part 1 – Section 100 Page 4 of 10 November 2014 . Expansion and Contraction. As with the Roadway Design part. general and specific. construction and maintenance. utilities in structures.03 INTERIM ADVICE NOTES AND TECHNICAL CIRCULARS – SPECIFIC Interim Advice Notes and Technical Circulars . This part consists of eleven sections that cover the general aspects of structures and bridge design. Retaining Walls and Pedestrian Bridges. Geotechnical. Interim Advice Notes and Technical Circulars will be developed and issued as two distinct types.03 PART 3 : STRUCTURE DESIGN The purpose of the Structure Design part is to identify the design details with which all structures are required to comply.Specific. falsework policy for bridge construction. and are further defined below. Structural Steel. 103. construction joint guidelines and responsibilities. this document is intended to be used in conjunction with the ADM Standard Specifications and the ADM Standard Drawings for the standardization of details for structures and bridges. This manual can only be revised by the issuance of an Interim Advice Note or Technical Circular authorized and signed by the Director of IRID. and as such have no influence or effect on other design sections.02 INTERIM ADVICE NOTES AND TECHNICAL CIRCULARS – GENERAL Interim Advice Notes and Technical Circulars . Deviations from the Roadway Design Manual on a project specific basis. 3. 104.01 Rural Roadways Rural roadway classification characteristics are as follows:  Freeway Version 2.0 Part 1 – Section 100 Page 5 of 10 November 2014 .01 ROADWAY TYPES BY FUNCTIONAL CLASSIFICATION Roadway Type for Design First Tier Classification Urban Rural Primary Boulevard Avenue Freeway Expressway Secondary Street Collector Local Access Lane Access Road It should be noted that there is often some overlap between the classes and categories. Lighting Design Guidelines.01 below differentiates between the urban and rural roadway types by their first tier classifications: Table 100. and expressways in particular. may penetrate into urban areas. 2. etc.rural or urban. Report Transmittals.ROADWAY DESIGN MANUAL Examples of such Interim Advice Notes and Technical Circulars are: 1.01 ROADWAY SYSTEM Roadways within the jurisdiction of ADM fall into two categories .01. 104 ROADWAY CLASSIFICATIONS 104. For example freeways. Table 100. which may have frontage lanes (service roads).02 Urban Roadways Urban roadways are required to accommodate high degrees of both vehicular movements and accessibility.  Collector A collector is a low to medium capacity road that serves to move traffic from local streets to primary roads. In such cases. These may be single or dual carriageway roads.ROADWAY DESIGN MANUAL A freeway is a roadway with both a very high capacity and speed.  Expressway An expressway is generally built to similar standards as a freeway.01. All intersections and crossings are grade separated. Urban roadway classification characteristics are as follows. Access to pedestrians and non-motorized vehicles is forbidden. and to provide the level of functionality needed to satisfy the current and future demands in Abu Dhabi. Posted speeds of 100 kph typically apply. with dual 3-lane (or more) carriageways. with typically low traffic volumes and speeds.  Access Road An access road is a low volume capacity single carriageway street.02 below indicates the relationship between the street family name defined by the Version 2. consistent with the street family classifications provided by the USDM:  Boulevard A boulevard is a high vehicle capacity dual 3-lane street. Freeways are typically “downgraded” to expressway standards on approaching urban areas. Posted speeds of 120 kph typically apply. which may have frontage lanes (service roads). although 120 kph can also be used. may permit increased levels of access and have dual 2-lane carriageways.0 Part 1 – Section 100 Page 6 of 10 November 2014 .  Access Lane An access lane is a very low volume capacity single carriageway street. Table 100. posted speeds of 80 kph to 100 kph are typical. 104. but normally operates at lower speeds. with typically very low traffic volumes and speeds.  Avenue An avenue is a medium vehicle capacity dual 2-lane street. with typically very low traffic volumes and speeds.  Street A street is a low vehicle capacity single carriageway street. 140 kph (rural) 60 .Allowable frequency D D Local circulation D 60 .80 kph (urban) 40 kph (urban) 30 kph (urban) 120 .100 kph (rural) 60 . May connect two Primary Roads Residential. secondary and local roads: Table 100.02 RELATIONSHIP BETWEEN USDM STREET FAMILY AND FUNCTIONAL CLASSIFICATION USDM Street Family Functional Classification (AASHTO) Principal Arterial Minor Arterial Collector Local Boulevard Major Collectors Avenue Minor Collectors Street Access Lane Table 100.0 Part 1 – Section 100 Page 7 of 10 November 2014 . industrial and recreational areas not served by a higher class. Minimum Level of Service Design Speed Weather related road closures . Serves international connections. military installations and seaports not served by Primary Roads.80 kph (rural) Once per 100 years Once per 50 years Once per 25 years * See Part 2 – Roadway Design for further details. Serves international connections and major military installations Connects two regions.03 summarizes the major characteristics of the first tier classifications.e.ROADWAY DESIGN MANUAL USDM and the functional classification system adopted by the American Association of State Highway and Transportation Officials (AASHTO): Table 100. primary. Access Access is controlled May be controlled Minimal control. Version 2.03 SUMMARY OF FUNCTIONAL CHARACTERISTICS FOR ROADWAY CLASSIFICATIONS Characteristic Primary Roads Secondary Roads * Local Roads Function Regional Transportation Regional transportation and/or service to major land developments Service Points Connects multiple regions. i. secondary and local). The roadway classification system is based on a hierarchy of roads.ROADWAY DESIGN MANUAL 104.0 Part 1 – Section 100 Page 8 of 10 November 2014 .02 DESIGN Roadway design standards are dependent upon the classification of the roadway (primary. Local Roads provide access to adjacent land. 104. Secondary Roads provide a combination of land access and movement of through traffic. ADM will determine the appropriate classification.03 CRITERIA FOR DESIGN CLASS DESIGNATION Table 100. Refer to Table 100. The Design Concept Report summarizes the design criteria to be utilized in the design.04 defines the characteristics of the urban/rural design classes as they relate to design requirements: Version 2. Primary Roads provide for movement of through traffic and have at-grade or gradeseparated intersections. which will also take UPC guidelines into consideration.03 for a summary of functional characteristics and Part 2 – Roadway Design for more details. 110 kph 50 .80 kph Version 2.60 kph 30 kph 20 kph Rural 60 .04 CHARACTERISTICS OF URBAN/RURAL DESIGN CLASSES Type Primary Roads Secondary Roads Local Roads Traffic Service: Urban and Rural Traffic movement primary consideration Traffic movement and access of equal importance Traffic movement secondary consideration Plot access secondary in consideration Traffic movement and plot access of equal importance Plot access primary consideration Plot Service: Urban and Rural Traffic Flow Characteristics: Urban Uninterrupted flow except at intersections Interrupted flow Interrupted flow Rural Uninterrupted flow Interrupted flow Interrupted flow Permitted Permitted Private and Commercial Access: Urban and Rural None or limited Connection Type for Public Roads: Urban At-grade intersections At-grade intersections At-grade intersections Rural Grade separated interchanges.90 kph 45 .ROADWAY DESIGN MANUAL Table 100.0 Part 1 – Section 100 Page 9 of 10 November 2014 . or slip ramps At-grade intersections At-grade intersections Urban Boulevards Avenues Streets Boulevards Avenues Streets Access Lanes Streets Access Lanes Rural Freeways Expressways Collectors Freeways Expressways Collectors Access Roads Collectors Access Roads Connects to: Average Running Speed for Off-Peak Conditions: Urban 40 . Policy and Procedures” manual for details. shoulders. etc. south. east.0 Part 1 – Section 100 Page 10 of 10 November 2014 . etc. Route designation and numbering facilitate rapid and accurate identification of specific locations in the event of emergencies.  design standards (design speeds.. signs. drainage structures. Route assignments are made by the ADM and DoT. Refer to the DoT “Route Numbering System . west).  origin/destination of the road. resulting from the roadway classification). i.e. accident reporting and analysis and in the inventory of roadway appurtenances. dependent upon road maintenance liability and based on the functional classification of each roadway with urban or rural factor jurisdictions.ROADWAY DESIGN MANUAL 105 ROUTE DESIGNATIONS The purpose of route designations is to provide the roadway user with a consistent expectation of:  relative direction (north. guardrails. Version 2. ROADWAY DESIGN MANUAL SECTION 200 : DESIGN CONCEPT DEVELOPMENT Version 2.0 Part 0 – Divider November 2014 . procedures and standards. Version 2.ROADWAY DESIGN MANUAL SECTION 200 . 201. 3) Construction Permits Division (CPD).02. The Master Plan is the base document from which the project’s roadway classifications are assigned. This data becomes the foundation for project road and bridge design.03 and 100.01. refer to the latest TPS (SDD) requirements. landowners. The planning layouts are used to identify the existing and proposed land use and development intensity. The Consultant is expected to develop the project by proper application of ADM policies.0 Part 1 – Section 200 Page 1 of 25 November 2014 .DESIGN CONCEPT DEVELOPMENT 201 TRANSPORTATION PLANNING 201. General Information). 2) Spatial Data Division (SDD). The Consultant is responsible for all data collection.Section 100. 100. The UPD (Utilities Section) is responsible for the development and approval of all service reservations. and field surveys. specifications and procedures.01 INTRODUCTION The pre-design process involves the collection of existing data from ADM. Roadway design standards are identified for each roadway classification (see Tables 100. in Part 1 .03 TOWN PLANNING SECTOR The Town Planning Sector (TPS) is divided into the following: 1) Urban Planning Division (UPD). 201. 201. The UPD (Planning Section) is responsible for the development and maintenance of the Master Plan and planning layouts. The Consultant will work with assigned staff to develop the project scope as per the Consultant Procedure Manual and identify applicable design criteria from the Roadway Design Manual.04. other government departments. utility agencies/authorities.04 MAPPING For standards.02 INTERNAL ROADS AND INFRASTRUCTURE DIRECTORATE (IRID) IRID is the lead department from which all road and bridge projects are initiated and approved. 100. combined with visual imagery or viewed directly in software packages like RiSCAN. 201. This mapping can be used for both design concept development and final design and should be limited to the broad roadway corridor.01 General Current.ROADWAY DESIGN MANUAL 201. The maps are generally used in route location studies to define transportation corridors and alternative alignments. ADM and TPS maintain a limited library of existing mapping which the Consultant may review for background information. The Consultant is responsible for providing base mapping for design concept development.01. The contact prints from the aerial photography are assembled to form a photo mosaic of the area under study to reduce distortion.0 Part 1 – Section 200 Page 2 of 25 November 2014 .04. Version 2.04.These consist of topographic maps compiled from airborne LiDAR data to capture large amounts of data over large areas and ground based LiDAR (fitted to a vehicle) to provide a greater amount of detail in specific areas. Survey Control/Field Survey. These maps can be used at larger scales for preliminary engineering activities including Design Concept Reports. Mapping scales and contour intervals generally suitable for the intended purpose are shown in Table 200.04. especially in urban areas and to supplement aerial mapping at specific locations where more detail and accuracy is needed. These points are used to control photo mosaic products that are significantly more accurate and can be prepared at a specific scale. accurate base mapping is an essential tool in transportation planning and design. either urban or rural. The specific mapping requirements depend on the length and complexity of the project and its location.The requirements for surveys are included in Section 203. Existing aerial and topographic maps may be available and suitable for use in consultation with ADM. Controlled Aerial Photography . Three types of aerial maps are used in the planning and design phases of roadway and bridge projects: Uncontrolled Aerial Photography – These maps are produced directly from the aerial photographs that normally cover large areas at a reduced scale. horizontal and vertical ground control points are set and marked in the field. Specific requirements will be identified in the Consultant’s scope of work.02 Topographic Mapping Topographic maps for a specific project shall be prepared in accordance with the following: Survey Control / Field Surveys .Prior to the flight. Aerial mapping is normally the most useful and cost-effective medium for larger projects. Topographic (Aerial or Mobile) Mapping . Data from LiDAR can be imported into CAD packages. Ground topographical surveys are used for smaller projects. These include wing points.02 and 200. 200.02 and 200. A title block is also required and shall be placed on each sheet. identification number and elevation.000 5 2 Preliminary Design (DCR): Rural Urban 1 : 1. North Point .Coordinate grid ticks shall be shown on the maps at intervals to suit the drawing.250 2 2 Rural Design 1 : 1.Mapping features and symbology will be prepared in accordance with the latest CAD Standards.All supplemental control points established for controlling aerial photography will be shown on the maps.250 1 : 1. The north point shall be oriented so that north points to the top or to the right of the map sheet. The tabulation will show the identification number. Map Index . Table 200.5 0.ROADWAY DESIGN MANUAL Drafting Standards .01 MAP SCALES AND CONTOUR INTERVALS FOR HIGHWAY DEVELOPMENT Purpose Version 2.All primary control points for mapping which were established during the initial field survey will be shown on the maps in their proper locations and with the appropriate symbol. A tabulation of the primary control points shall also be shown in the original survey notebook.5 Detailed Site Design 1 : 100 1 : 250 0.01. This diagram shall show the position and relationship of each sheet to adjacent sheets.Natural and manmade features.03. supplemented by the standard symbols shown in Figures 200.01.5 Urban Design 1 : 500 0.5 Part 1 – Section 200 Page 3 of 25 November 2014 . Planimetric Features . spot elevations.03.A sheet index diagram shall be prepared for each mapping project.A north point shall be placed on each map sheet.000 (max) 1 : 5. Coordinate Grid .250 0. Cut lines shall also be labelled so that each sheet may be joined accurately to adjacent sheets. coordinates and elevation of the point. Supplemental Control Points . See Figure 200. Primary Control Points . topographic features and relevant political subdivision lines shall be plotted on the maps as shown in Figures 200. analytically bridged points. and aerial photo centres.0 Scales Interval (m) Route Location Studies: Mountainous Rolling to Flat 1 : 5. parkways.ROADWAY DESIGN MANUAL 201.05 PROJECT LIMITS ADM will determine the limits of the project. and roadside improvements that enhance the appearance. medians.0 Part 1 – Section 200 Page 4 of 25 November 2014 . sidewalks. Version 2. Typically. The project limits may also be determined by phased implementation considerations. the limits include the roadway/bridge. maintainability and safety characteristics of the project. 0 Part 1 – Section 200 Page 5 of 25 November 2014 .Boundaries and Monuments Version 2.01 Standard Mapping Symbols .ROADWAY DESIGN MANUAL Figure 200. ROADWAY DESIGN MANUAL Figure 200.0 Part 1 – Section 200 Page 6 of 25 November 2014 .Natural Planimetric Features Version 2.02 Standard Mapping Symbols . 0 Part 1 – Section 200 Page 7 of 25 November 2014 .Manmade Planimetric Symbols Version 2.03 Standard Mapping Symbols .ROADWAY DESIGN MANUAL Figure 200. correspondence. Table 200. These factors are both natural and man-made and have been divided into two major categories. calculations and other design documentation associated with the subject project. Socio Economic/Community Resource Data (Section 202.02 below lists the agency or authority responsible for transportation related functions. reports. It is the Consultant’s responsibility to assess each factor and develop a functional and Version 2.Town Planning Sector (TPS) Landscape and Public Realm ADM – Parks & Recreation Facilities Division (PRFD) Public Transportation Department of Transport (DoT) 202 ENVIRONMENTAL FACTORS INFLUENCING DESIGN 202.07 INTER-DEPARTMENTAL COORDINATION Throughout the development of the project. This will contribute significantly to public acceptance and the ultimate success of a project.Town Planning Sector (TPS) Department of Transport (DoT) Utilities ADM . coordination with ADM as well as other government departments is essential.02) and Natural/ Environmental Resource Data (Section 202.0 Part 1 – Section 200 Page 8 of 25 November 2014 .02 MUNICIPAL AGENCIES Function Agency/Authority Road/Bridge Construction ADM – Internal Roads and Infrastructure Directorate (IRID) Planning Urban Planning Council (UPC) ADM . The following sections describe the various environmental factors that comprise each of the two categories. The Consultant will include this information on all drawings. The Consultant is expected to identify the requirements of the involved government departments.06 PROJECT IDENTIFICATION AND NUMBERING ADM will assign the Title and Number for each individual roadway and bridge project.ROADWAY DESIGN MANUAL 201. and insure that the project design addresses these requirements. Table 200. 201.03). The identification of these resources enables the project to be developed to avoid and/or minimize impact on these resources to the greatest extent practicable.01 INTRODUCTION There are a number of important environmental factors that influence the design of all roadway and bridge projects.Town Planning Sector (TPS) Urban Planning Council (UPC) Parking ADM (IRID) Department of Transport (DoT) Right-of-Way ADM . 04). the Consultant must conduct a field survey of the existing land uses adjacent to the project. published by the Urban Planning Council (UPC) is the primary document used to identify the types and locations of designated land uses. In rural areas. The goal is to develop a functional design that accommodates. not only critical to meeting the access needs of individual disabled people. commensurate with the type of land use and the roadway classification (see Part 1 – Section 100.03 and 100. In these cases. In rural areas.02. Plan Abu Dhabi 2030 (Urban Structure Framework Plan). disabled parking/access.0 Part 1 – Section 200 Page 9 of 25 November 2014 . 202.ROADWAY DESIGN MANUAL compatible design. The roadway volumes used to determine the “level of service” (existing and 20-year projection) must include the trip generation associated with the adjacent land uses. formal information regarding land use may not be available.02 SOCIO ECONOMIC / COMMUNITY RESOURCE DATA The Consultant shall consider each of the following factors as part of the development of project design. 100. To assist with the planning involved with the development of the design.02. Version 2. ramps to sidewalks and buildings. The following factors must also ensure that the needs of pedestrians. The Consultant is required to provide adequate parking and access to adjacent land uses. children and disabled people are carefully considered. General Information. Consultants are to ensure that the pedestrian environment is ‘accessible to all’. 202. will then be used to identify potential improvements to be designed as part of the roadway project. combined with the field survey data. where the land usage is less defined. facilitating the issuance of the environmental permit. the Consultant should map all resources that are capable of being placed onto a map. In urban areas. In this context ‘accessible to all’ means continuous and level sidewalks and paths. cyclists. The aforementioned information. The Consultant is responsible for ensuring that an accredited Environmental Consultant is used to study the environmental aspects of the project. the current land use is typically agricultural and will remain as agricultural unless there is information stating otherwise.01 Land Use The project plans must accommodate existing and future land use to the full extent possible. maintains or enhances the integrity of each socio economic and community resource with minimal disruption. but contributing towards social inclusion and quality of life to a much wider section of the population. Tables 100. all of which must be clear of unnecessary obstructions. but will also take into consideration information obtained from developers working in the vicinity of the proposed scheme. Table 200.02. Version 2. As such. sidewalk. The Consultant is responsible for identifying all public services which may be affected by the project.0 Part 1 – Section 200 Page 10 of 25 November 2014 .ROADWAY DESIGN MANUAL 202.03 Public Services The development of all road and bridge projects typically affects many public services.02 Growth Projections The Consultant is to liaise with all concerned authorities to establish growth projections applicable to the area of the project. It is the Consultant’s responsibility to assure ADM that the design and construction phasing meets the approval of the affected public services. This will not only include UPC and TPS master planning projections.02. and bridge. This can result from encroachment of the improvement project beyond the existing roadway. In addition. pre-design coordination with public services is required to incorporate design approaches and construction phasing that minimizes the project impact. the Consultant is also responsible for compiling all relevant design requirements from the affected public services and incorporating these parameters into the project design.03 identifies the various public services and the responsible agency/authority for each. 202. The Consultant should liaise with the ADM School Safety Zone Coordinator.04 Schools Schools are an important national resource.ROADWAY DESIGN MANUAL Table 200. the Consultant is expected to adapt the project’s design to accommodate each school’s needs.PRFD Police General Headquarters of Abu Dhabi Police Directorate of Traffic and Patrols Fire Abu Dhabi Civil Defence Security Abu Dhabi Civil Defence Abu Dhabi Police Schools ADM – TPS Ministry of Education Abu Dhabi Education Council (ADEC) Sanitation Health Authority of Abu Dhabi (HAAD) Abu Dhabi Sewerage Services Company (ADSSC) Waste Center of Waste Management Parking ADM – IRID DoT Recreational ADM – TPS ADM . ADM Traffic Services Section and authorized staff and/or management of any affected schools to establish the requirements.02. Therefore.03 PUBLIC SERVICES Service Agency/Authority Road/Bridge Construction ADM – IRID DoT Landscape and Public Realm ADM .0 Part 1 – Section 200 Page 11 of 25 November 2014 .PRFD Navigable Waters Critical Infrastructure and Coastal Protection Authority Mail Service Emirates Post Group Public Transportation DoT National Railway and Metro Rail System Etihad Rail – National Railway DoT – Abu Dhabi Metro Rail System Mosques General Authority of Islamic Affairs and Endowments Mosque Development Committee Hospitals Health Authority of Abu Dhabi (HAAD) Archaeology Abu Dhabi Authority for Culture & Heritage 202. The design shall accommodate and preserve sufficient access to all facilities that are affected by project design. Version 2. but any anticipated deficiency should be highlighted at the early stages of the design process. staff parking requirements. Parking supply should be in accordance with the guidelines on this type of facility (see Section 202. the Consultant is required to provide plans which can be used to construct the necessary improvements either in conjunction with the roadway/bridge project or as a separate project. accessibility and wayfinding. This is intended so that construction can be undertaken on the school sites during scheduled school closures or outside of normal school working hours..e. For each school. Safe pedestrian crossing locations.13). including beginning and end of a school day for different grades. As with all other adjacent property improvements. taking into consideration the integration of different modes of transport and pedestrian safety (especially due to the higher risks associated with children) and as further detailed below: 1. the UPC Master Plan and Abu Dhabi Education Council shall be consulted to identify these sites within and/or adjacent to the project limits. access routes to main roads. parking and drop-off/pick up locations for school buses. These include:  school bus traffic  crosswalks  school yard fencing  parking  drop-off/pick-up waiting time  landscaping  noise attenuation (i. etc. there are a number of factors that must be considered in the project design. 2. Operational characteristics of the school should be thoroughly discussed with the concerned people. drop-off/pick-up locations for parents. Version 2. Operational requirements of the facility should be well analyzed and alternatives should be produced accordingly. drop-off/pickup waiting time. insulated windows.0 Part 1 – Section 200 Page 12 of 25 November 2014 .02. Cycle and pedestrian routes for non-motorized students/parents. 3. sound-proof walls)  other safety improvement relocation of affected structures. as necessary  affects on potential school expansion In the case of new school site development. and observed at the site.ROADWAY DESIGN MANUAL Initial concept designs should study options to achieve better circulation. Dedicated cycle storage areas. careful planning of access routes and parking facilities is vital for the proper and effective functioning of hospitals.02. Public transportation and taxi stop locations. 4. Accessibility and connectivity to main roads. 202.02. 2. way-finding and pedestrian safety. Parking supply should be in accordance with the guidelines on this type of facility (see Section 202. accessibility. circulation.06 Malls Concept designs should be given careful consideration in terms of integration of different modes of transport.ROADWAY DESIGN MANUAL 202. 7. 3. Table 200.02. 202. Taxi drop-off and pick-up locations.08 Utilities Major road and bridge projects typically include improvements to all affected utility services. Construction works cannot be undertaken during prayer times under any circumstances.02. The following factors should be considered during the preparation of alternative designs: 1. A survey of existing utilities is Version 2. This also includes preparing plans and specifications for these improvements. Final design approval of the utility improvements by the utility agencies is also required.13). The Utilities Section of the Town Planning Sector is responsible for establishment and approval of all Service Reservations. The Consultant shall identify all existing and proposed Mosques within close proximity to a proposed project. The Consultant shall consult with the concerned authorities at the outset of the project to clearly establish these requirements. The project design shall avoid impact to Mosques and shall accommodate and preserve sufficient access to these sites. 6. Safe pedestrian crossing locations. Parking requirements. 202. Pre-design activities require coordination with many agencies/departments. 5.02.0 Part 1 – Section 200 Page 13 of 25 November 2014 .04 lists the Responsible Agencies/Authorities for Utilities. which require urgent and safe passage to the facility at any time and in unpredictable volume must be taken into consideration when designing the external road layout.07 Hospitals Due to the nature of these facilities. Traffic circulation within the parking zones.05 Mosques Mosques are extremely important to the Islamic faith and cannot be relocated or impacted in any way. Access for emergency vehicles.  affect the horizontal and vertical alignment of the roadway.04 PUBLIC SERVICES Service 202. All embassies. Cost Estimate.ROADWAY DESIGN MANUAL required.  need to be replaced/upgraded due to future development.PRFD Drainage ADM – IRID Design Section Gas ADNOC District Cooling Tabreed ITS DoT – Traffic Management Center Falcon Eye & Security Cameras National Emergency and Crisis Management Authority Signal Corps Abu Dhabi Traffic Police Speed and Red Violation Cameras Abu Dhabi Traffic Police Security Nearly every project is affected by some level of security issue. as-built plans and other available information.02. The UPC “Abu Dhabi Safety and Security Planning Manual” is to be followed to ensure adherence to safety and security planning and design principles. and associated channeling devices. In the case of future or relocated utilities.09 Agency/Authority Water ADWEA/ADDC (Water) Transco (Water) Sewer ADSSC Telephone Etisalat / Du Electricity ADWEA/ADDC (Power) Transco (Electricity) Lighting ADWEA/ADDC (Street Lighting Section) ADM (Street Lighting Section) Irrigation ADM . Refer to Part 1 Section 322. government installations. The purpose of the utilities survey is to determine which utilities can:  remain in place based on field surveys. banks and VIP homes are protected by guards with guardhouses. it may be necessary to preserve adjacent land for utility installation and relocation. Version 2. Table 200. palaces. The associated costs for utility work shall be identified as part of the design reflected in the project cost estimate for the Design Concept Report. many of these facilities interfere with road and bridge projects. schools. As a result.0 Part 1 – Section 200 Page 14 of 25 November 2014 . and.  be protected and/or relocated. this should be based on the parking demand calculated based on applicable rates.0 Part 1 – Section 200 Page 15 of 25 November 2014 . This is intended so that construction can be undertaken outside of the project right-of-way at the convenience of the affected property owner. For example. etc. Version 2. As with all other adjacent property improvements. access. Stops or Turnouts  Staging areas for Regional Transportation Hubs  Police Enforcement Pads  Pedestrian Walkways and Islands  Special Landscape Areas The Consultant should liaise with all relevant parties for the above.13 Parking Requirements In cases where a parking study is required. including but not limited to.02. parking.12 Local Transportation/Circulation In order to ensure that the project fully incorporates local transportation/circulation needs. This will be done through direct coordination with representatives of ADM. Since each case will vary. UPC. the Consultant is required to provide plans which can be used to construct the necessary improvements either in conjunction with the roadway/bridge project or as a separate project. facility relocation. existing access shall be maintained as well as accommodating special features of the non-project site. The Consultant is also responsible for assuring ADM that the proposed improvements located outside of the project right-of-way are agreeable to the affected property owner. As a result. published by the DoT.11 Economics The Consultant shall assess the economic conditions that exist within the project study area. The Consultant shall develop a design that seeks to minimize adverse impacts on these and other economic indicators. including income and employment characteristics. the Consultant shall address the following:  Need for Public Transit Corridors. Traffic Police and ADM Traffic Services Section. the DoT. 202. 202. adjacent landowners and governmental departments is required to lessen the impact of the road/bridge improvement project on commercial activities.10 Commercial Activities The effects of commercial activities on the road and bridge design shall be taken into account. coordination with the Town Planning Sector.02. requires review by the affected party and ADM. the limits of improvement. tax base and property values.ROADWAY DESIGN MANUAL The Consultant is required to minimize the relocation of affected facilities as part of the road and bridge project.02. 202. Reference should be made to the “Trip Generation and Parking Rates Manual for the Emirate of Abu Dhabi”. 202.02. 02.35m +1. The designer shall comply with the requirements of the appropriate agencies in the case of offstreet parking facilities and shall ensure that capacity analysis of vehicle access to such car parks.5m +1. subject to approval of ADM. refer to the latest “Public Realm Design Manual” (UPC) and associated PRFD design/review standards from the Parks & Recreation Facilities Division (PRFD).5m x 6. parks and streetscape. including provision for disabled people. Particular consideration needs to be given to access control systems (gates. The basic dimensions for parking bays are:  Standard perpendicular and diagonal parking bays Angles 30°. Version 2.  Standard parking bay (parallel): 2. hotels. but not limited to. The designer shall provide a table showing calculated parking demand and supply as well as a diagram that clearly shows all parking spaces provided. 45°. beach access. golf courses.7m (min) x 5. subject to the approval of ADM.  Accessible (disabled) parking: 2.0 Part 1 – Section 200 Page 16 of 25 November 2014 .  Parking next to walls or physical obstructions: Standard width + 200mm.5m x 5.5m (but see note below). clubs.0m if the parking provision is not adjacent to a main circulatory route.5m. etc. 202.5m. As with all other adjacent property improvements. the Consultant is required to identify the potential effects on adjacent recreational facilities and minimize the relocation of affected facilities as part of the roadway/bridge project.  Accessible van parking: 3. As part of the pre-design activities. rates from the Institution of Transportation Engineers may be used.5m.5m x 5. 60° and 90°: 2. based on the highest peak traffic inflow. playing fields. Note: The bay length for a standard parallel parking bay may be reduced to 6.14 Recreation A variety of recreation and leisure activities are available to the residents of Abu Dhabi.ROADWAY DESIGN MANUAL If a suitable land use code is not specified by the DoT. is undertaken. Surveys of comparable local developments may also be used. These can include.) and their capacity in relation to the expected peak traffic inflow. For design guidance. Standard parking arrangements are also provided on the ADM Standard Drawings. movie theatres and entertainment complexes. the Consultant is required to provide plans which can be used to construct the necessary improvements either in conjunction with the roadway/bridge project or as a separate project. ticketing systems. barriers. Road/bridge improvements including utility locations shall be designed to minimize removal of vegetation. The goal of the government is to identify these sites as they are discovered. 202. The results of this survey are to be agreed with ADM.02. and where appropriate. Pre-design activities include a survey of existing flora and fauna as part of the design survey stage. in accordance with PRFD requirements. PRFD and EAD.Headquarters P. The goal is to develop a functional design that avoids or minimizes impact to the natural environment to the greatest extent practicable. The Consultant is to also liaise with EAD. United Arab Emirates Natural/environmental resources within a project study area shall be assessed and considered during development of the project design. To facilitate the planning process involved in the development of the design. Box: 45553 Tel: +971 (2) 4454777 Fax: +971 (2) 4463339 E-mail: customerservice@ead. and Version 2. PRFD will guide Consultants to the relevant design documents. The Consultant shall also meet with representatives of the Municipality to determine the significance of the site and present recommendations as to appropriate preservation procedures The Consultant should also liaise with the Environment Agency Abu Dhabi (EAD) for preservation and conservation areas. 202.O. and the Abu Dhabi Tourism & Culture Authority (TCA) for historical sites. The landscaping survey includes the identification of the number.0 Part 1 – Section 200 Page 17 of 25 November 2014 . size.01 Protection of Existing Amenities Preservation of any existing landscape treatment or plantation adjacent to proposed roadway projects is extremely important. EAD contact details are given below: EAD .03. During the pre-design process.ae Al Mamoura Building (A). preserve the sites. type.ROADWAY DESIGN MANUAL 202. Muroor Road Abu Dhabi.15 Historical Site Identification and Preservation The government recognizes the importance of all historical sites and structures that relate to Abu Dhabi’s cultural development. condition.03 NATURAL / ENVIRONMENTAL RESOURCE DATA ADM regulations require compliance with EAD mandatory procedures relating to environmental considerations. the Consultant should map all environmental resources capable of being placed on a map. information regarding historical sites shall be compiled from available sources as well as conducting an initial site survey. The public realm design should be undertaken by the Consultant.  Furnishings.e. and drainage. affect the project cost. Roadway profiles.). Mapping. 202. The scale of each sheet should be adequate to clearly convey the information contained on it. Guidance on design submission requirements is available from PRFD. flowers. verges and other designated areas within the project limits. succulents. The presence of any vegetation that is specifically protected by decree. reverts to PRFD. are directly affected by topography.03. so all large distribution lines require design input and approval from the Abu Dhabi Sewerage Services Company (ADSSC). new surveys shall be required to establish the topography for the Version 2. shall also be identified during the survey. which. after which.  Shading. PRFD uses ADM third party design review procedures and Standards. and its common name. Initial maintenance and operation of the irrigation systems (1 to 2 years) are the responsibility of the Contractor. landscaping. or endangered. Public Realm Design All road schemes in urban areas should consider the full right-of-way corridor (ROW) and therefore include public realm design of the medians. horizontal alignment.04. Utility Corridor Design Manual (UCDM). Urban Street Design Manual (USDM). Each sheet should contain a legend. As discussed in Section 201. the Consultant is expected to review existing maps.02 Topography Topographic data is important to the development of the Design Concept. mainly concerning the maintenance of all assets (including irrigation network. Walking and Cycling Master Plan (WCMP).  Public realm lighting.  Universal access requirements:  Pedestrian and cycling connectivity. if so required:  Right-of-way corridor compliance with the latest standards. For trees. if agreed to operate and maintain. which lists the botanical name of the plant. and grasses. in turn. shrubs. ensuring that the following are considered as part of the project. In addition. etc. All proposals must conform to the latest PRFD Landscaping and Irrigation requirements to ensure compliance to current standards.0 Part 1 – Section 200 Page 18 of 25 November 2014 . Vegetation surveys shall be in accordance with BS 5837:2012. Water for irrigation should be sourced from the treated sewage effluent (TSE) network. or that is considered rare. The Consultant should prepare irrigation designs and obtain PRFD approval and the same for connections to the existing feeder network. i. The survey information should then be presented on a scaled plot plan. the size of the tree shall also be listed.  Planting. Public Realm Design Manual (PRDM). threatened.ROADWAY DESIGN MANUAL location of all trees. those habitat areas that support rare.08 Hazardous Materials The Consultant shall conduct a survey to identify the actual presence. or likelihood of hazardous material sites within the project study area. such as mosques.03. The Consultant is responsible for identifying the types of flora and fauna species. threatened or endangered wildlife species.07 Visual / Aesthetic The Consultant shall assess the existing visual and aesthetic appearance of the project study area. 202. the Consultant should consider the effect that the project will have on the visual and aesthetic environment upon build-out. especially those that supply drinking water. Ideally. that are likely to utilize the habitat. the Consultant shall develop a design that minimizes impact to water resources.ROADWAY DESIGN MANUAL project. shall also be identified within project limits. if any.03.03 Water The Consultant shall identify and determine the importance of all freshwater and saltwater features within the study area.03.0 Part 1 – Section 200 Page 19 of 25 November 2014 .05 Air Quality The Consultant shall assess a project’s affect on existing air quality to determine whether or not it will result in significant deterioration due to increased air emissions. 202. The Consultant shall strive to develop a design that will have the least increase in noise levels to these receptors. 202.03.03.03. schools and residential dwellings.06 Noise The Consultant shall assess a proposed project’s affect on ambient noise levels to determine whether or not it will result in a significant deterioration from the existing condition. 202. The Consultant’s design shall avoid. In developing the design.04 Flora and Fauna The Consultant shall describe any existing wildlife habitat within the project study area. The objective of the design is to develop a project that compliments rather than contrasts the existing visual and aesthetic character of the area. Noise sensitive receptors. This will reduce the health and safety risk and overall Version 2. shall be identified within the project limits. Aquifers and wells. In developing the design. 202. Views from the project of the surrounding environment as well as views of the project from adjacent vantage points shall be considered. The Consultant should liaise with the ADM GIS Section for topographical information. 202. where possible. the project design should be developed to avoid impacting such hazardous sites. the Consultant shall avoid impacts to water resources to the greatest extent possible. If avoidance is not an option. and evaluate subsurface and surface data in order to predict the behaviour of the soils and materials along. and adjacent Version 2. In addition. 203. 202. interpret.  Technical Guidance Document for Construction Environmental Management Plan (CEMP). the Consultant shall take appropriate steps to remediate the hazardous site prior to construction in order to reduce the potential health/safety risk. These technical investigations are initiated in the data collection phase and continue through the development of the Design Concept Report. Other guidelines are available dependent upon the requirements of specific projects and these are available for viewing on the Environment Agency website. in compliance with the relevant regulations of the EAD. The basic technical investigations include:  Geotechnical  Traffic Data Collection  Survey Control/Field Surveys  Drainage Surveys. 203 TECHNICAL INVESTIGATIONS 203.02 GEOTECHNICAL The objective of highway geotechnical work should be to seek. The requirements and processes associated with environmental permitting are described in the “Standard Operating Procedures for Permitting of Development and Infrastructure Projects in Abu Dhabi”.ROADWAY DESIGN MANUAL project cost.0 Part 1 – Section 200 Page 20 of 25 November 2014 . If a hazardous materials site cannot be avoided.  Technical Guidance Document for Strategic Environmental Assessment (SEA).01 INTRODUCTION All roadway and bridge projects require technical investigations. for example:  Technical Guidance Document for Preliminary Environmental Review (PER).  Technical Guidance Document for Environmental Impact Assessment (EIA). technical guideline documents are also available including. This subsection identifies the initial activities associated with these investigations. The updated list of accredited environmental consultants in Abu Dhabi can be downloaded from the EAD website. to establish the basic building blocks of the design.04 ENVIRONMENTAL PERMIT The Consultant must obtain the Environmental Permit for the concerned project through a third party accredited environmental consultant. Geotechnical. growth factors derived from historical count data compared with data from recent surveys may be used. Traffic Police and any other concerned agencies prior to commencing geotechnical investigations. ADM as well as other Municipality and Government agencies. as agreed with ADM. Projections of future traffic shall primarily be derived from applicable traffic models of the concerned area. 203. highway legislation and for many other purposes. the alignment.01 TRAFFIC DATA COLLECTION Introduction Traffic volumes are needed for highway planning. traffic accident surveillance. For review of existing geotechnical reports. if available. analyzing. The procedures which follow establish the minimum requirements. 203. public information. this does not preclude the Engineer from using more sophisticated procedures.03 203. Design Concept Report and Part 3 . The Consultant shall obtain approval from ADM. However. priority determinations. The existing data will be used to define the number of additional soil borings and the testing requirements for the boring program as described in Part 1 . highway maintenance. The Traffic Service Section may be able to provide assistance in this regard.02 Traffic Projections ADM roadways are designed to serve traffic volumes anticipated over a 20-year time frame.0 Part 1 – Section 200 Page 21 of 25 November 2014 . Existing flows may be obtained from existing Automatic Traffic Counters (ATC) located within the city. monitoring and controlling traffic movement on the highways. The application of such growth factors should be agreed with ADM. The Consultant should coordinate fully with the ADM Traffic Services Section and the DoT.Section 300.Section 700. The resulting information is to be presented in a technical report to be used in the project design. Version 2. However.ROADWAY DESIGN MANUAL to. Data collection includes research of existing geotechnical reports which were prepared for other projects in the geographic area as well as field reviews and preliminary testing. In cases where traffic model outputs are not required or not available. it should be noted that the traffic data collection and projection techniques described herein are specifically intended for providing traffic volume data required for roadway and bridge design.03. which hold relevant information of geotechnical information in the immediate vicinity of the project.03. should be contacted. including the use of data from permanent automatic collection stations. research purposes. project cost-benefit comparisons. 01 Automatic Traffic Counts The duration of counts should be agreed with ADM.ROADWAY DESIGN MANUAL 203.03. 16 and 24-hour averages for weekdays and weekends (5-day and 7-day averages)  Graphical summaries as agreed with ADM Errors and anomalies are to be highlighted and omitted from subsequent analysis. Unless otherwise specified.03.03.03. Data supplied should be on the basis of 24hour classified counts. the minimum time periods to capture the peak flows should be:  AM – 06:30 to 09:00  Noon – 12:30 to 15:00  PM – 17:30 to 20:00 The raw data is to be processed and presented in an Excel spreadsheet format to include (at Version 2.03. The raw data is to be processed and presented in spreadsheet format and should include:  Time and date  Location (coordinates)  15 minute and hourly totals  Totals by vehicle class and direction  Calculation of morning. 203. ATC data should be classified into the standard 6 classes as listed below or as specified by ADM:  Motorcycles  Passenger cars  Buses  Heavy Goods Vehicles (HGV)  Light Goods Vehicles (LGV) and  Other Vehicles 203. However.0 Part 1 – Section 200 Page 22 of 25 November 2014 .03 Procedures for Collecting Traffic Volumes The following sections outline the methods of obtaining traffic volume data.02 Classified Turning Movement Counts The time period for the peak hour counts will vary depending on location and project and should therefore be agreed with ADM. afternoon and evening peak hours  12. in the absence of direct guidance. 03. The raw data is to be processed and presented in spreadsheet format and should include:  Time and date  Location (coordinates)  Classification in 10 km/hr groups by direction  Average and 85th percentile speed in hourly intervals  12.04 Other Surveys Other surveys that may typically be required include:  Origin and destination  ANPR (Automatic Number Plate Recognition)  Speed radar  Parking occupancy  Freight Version 2. 203.ROADWAY DESIGN MANUAL minimum):  Time and date  Location (coordinates)  Schematic plan of permitted movements  15-minute and hourly totals by individual movement. the Consultant should provide evidence of appropriate spot checks carried out by the survey supervisor. a detailed methodology of how the counts will be conducted must be set out for approval of ADM.0 Part 1 – Section 200 Page 23 of 25 November 2014 . unless otherwise agreed with ADM. In such cases. and by vehicle class  Calculation of morning.03 Automatic Speed Surveys Data should be supplied on the basis of 24-hour counts with the duration of survey in days to be agreed with ADM. Automatic Number Plate Matching surveys or Camera Recorded Counts are required. afternoon and evening peak hours For turning count surveys. At large roundabouts. 16 and 24-hour average and 85th percentile speeds for weekdays and weekends  Graphical summaries as agreed with ADM Errors and anomalies are to be highlighted and omitted from subsequent analysis.03. 203. the preference is for camera recorded data or automatic lane counters where raw data can be retained for verification.03. by approach.03. When counts are carried out manually. Setting horizontal and vertical control is of great importance in mapping. This system shall be used for all surveys.04 203. For most topographic surveying. 203.04.04. 203.02 Horizontal Control The current inventory of horizontal control points established in the vicinity of the project will need to be investigated. the open traverse is used. all ADM design work will be referred to the Ras Ghumays vertical datum. traverses furnish satisfactory control. usually mean sea level. The closed traverse can be closed to form a net which is accurate to the degree required. Although some authority projects may use their own datum.0 Part 1 – Section 200 Page 24 of 25 November 2014 . The need for setting new horizontal control points will be ascertained from the existing data.03 Vertical Control The vertical control is to be referred to the Ras Ghumays datum. Version 2. Relative position in the vertical plane can be maintained by a series of benchmarks in the map area. For strip maps. Relative position in the horizontal plane is maintained by horizontal control.04 Coordinate System A Coordinate System has been established by TPS. 203. TPS should be consulted on the order of accuracy and status of existing primary and secondary control points.01 SURVEY CONTROL / FIELD SURVEYS Introduction Each project requires initial field surveys to establish baseline topographic information for project scoping and design.ROADWAY DESIGN MANUAL  Public transportation patronage  Pedestrian  Cyclist In all such cases. 203. a detailed methodology of how the counts will be conducted must be set out for approval of ADM.04. For area maps. The open traverse can be tied to fixed points at each end.04. the closed traverse is used. Horizontal control consists of a series of points accurately fixed in position by distance and direction in the horizontal plane. These benchmarks are referred to a known datum. Drainage” for further details. provide cross sections and existing pavement elevations at the limits of improvement. has been established. Reference should be made to the ADM “Roadway Design Manual .05 Field Surveys Field Surveys will be required on nearly every project to supplement the aerial topography. Version 2. 203. reflect new existing features. including applicable alternative alignments. The survey will record the location. Photographs should be taken to supplement the data. A detailed survey of the existing greenery impacted by the project will be required.ROADWAY DESIGN MANUAL 203. size and limits of all trees shrubs and flower beds within the limits of improvement. Once the horizontal alignment. record underground utility or drainage features.0 Part 1 – Section 200 Page 25 of 25 November 2014 . This information will be recorded on drawings and used to investigate alignment adjustments or alternatives that will minimize the removal of greenery.04. The staking interval and definition of the project geometrics required will be determined on a project specific basis in consultation with the Municipality Representative. obtain building floor elevations and other related information needed for preliminary and final design. the roadway centreline will be staked in the field to enable close examination of the roadway location by ADM representatives and Consultant staff.05 DRAINAGE SURVEYS The Consultant is responsible for a comprehensive survey of drainage facilities and conditions and data collection during the pre-design activities. ROADWAY DESIGN MANUAL SECTION 300 : DESIGN CONCEPT REPORT Version 2.0 Part 0 – Divider November 2014 . ROADWAY DESIGN MANUAL SECTION 300 . Design Concept Development. many of which are initiated in the data collection phase as described in Part 1 .DESIGN CONCEPT REPORT There are four stages to the design process which are as follows:  Planning and Study (Pre-Concept). The role of a DCR is to summarize the needs. The report is to be prepared under the direction of an experienced engineer designated by the Abu Dhabi City Municipality. Part 1 . Version 2. The DCR is the project scoping document and the basis for selecting the project design. contains a discussion of the specific requirements and content of a DCR.  Conceptual Design.01 below. The basic roadway configurations shown in the DCR will be carried forward to the final design phase.0 Part 1 – Section 300 Page 1 of 21 November 2014 .  Preliminary Design. Note that this section discusses the requirements of the report to be prepared at the conclusion of the concept design stage only and similar reports will be required for the other phases. 301 CONTENTS ADM requires the preparation and approval of a Design Concept Report (DCR) prior to commencing final project design. includes a discussion of the background information and data collection activities necessary to develop the design concept. Design Concept Report.  Final Design. The scope of the project is defined and the design criteria identified.Section 200.Section 200. This Section. A typical Table of Contents for a DCR is provided in Table 300. The preliminary engineering activities associated with the DCR involve preparation of numerous technical studies and reports. These are defined in more detail in the ADM “Consultant Procedure Manual”. costs and overall impacts of the proposed roadway or bridge project. although this may be modified according to the requirements of specific projects. The DCR will summarize the results of these individual reports under the respective topics. These are prepared as standalone documents and are included as Appendices to the DCR. Design Concept Development. alternatives.  Structural Engineering. structures.  Civil and Roads Engineering (related to roads and highways. the Consultant should take into consideration a number of factors when analyzing and designing a project and these general areas are listed below:  Planning and Design.ROADWAY DESIGN MANUAL Table 300. Typical Sections and Architectural Features In addition. etc). Traffic Engineering and Modelling. walls. geometrics. Plans. lighting. road signs and markings.  Transportation Planning. Profiles.01 DESIGN CONCEPT REPORT (DCR) Typical Table of Contents  Executive Summary  Introduction  Traffic Analysis  Description of Alternatives  Design Data  Typical Sections  Geometrics  Interchange/Intersection Configurations  Parking Study  Hydrology and Hydraulics  Subsurface Investigations and Preliminary Geotechnical Risks and Opportunities Identification  Bridge Type Selection  Utility Impact Analysis  Socio-economic Analysis  Agriculture Impact  Public Feedback  Signing and Pavement Markings  Lighting  Construction Staging  Cost Estimate  Conclusion/Recommendations  Drawings. Version 2.  Drainage Engineering (including hydrology and hydraulics).  Traffic Impact Studies (including parking study).0 Part 1 – Section 300 Page 2 of 21 November 2014 .  Operation and Management Strategy. time and cost decisions.  Landscape Architecture.  Environmental Considerations.  Electromechanical.  Stakeholder Requirements. Drawings that accompany the report bound separately in A3 size. Larger projects may require separate packaging of Version 2. For smaller projects the documents should be bound together. Furthermore.ROADWAY DESIGN MANUAL  Geotechnical and Foundation Engineering (including subsurface investigations) and corresponding land use.  Pedestrian Movement.  Quantity Surveying (including cost planning and life cycle costing).  Sustainability. 301.  Completed Checklist as per QA/QC Procedures. Studies and Reports bound in A4 size.  Architecture (related to any proposed structures).  Topographical and Bathymetric Surveying.  Safety. the discussion under each topic will address interdisciplinary relationships necessary to coordinate all technical aspects of the design concept. Written portion of the report bound separately in A4 size. Technical Memorandums.  Value Engineering.  Constructability.  Project Schedule.  Risk Management.0 Part 1 – Section 300 Page 3 of 21 November 2014 .  DCR (Appendices).  DCR (Volume II). Utility and Lighting Engineering (including utility impact analysis). The sections that follow provide guidance for the development of the technical studies and requirements for presentation of the material in the DCR.  Economic Feasibility Studies (including socio-economic analysis).01 FORMAT The DCR will be prepared and packaged as follows:  DCR (Volume I). Appendix B.  Project Location Plan.ROADWAY DESIGN MANUAL the reports.  Design Concept Report. Each document will include the following information on the cover:  Abu Dhabi City Municipality logo. or Appendix No.  Consultant details.  Project Number. titled as Appendix A. Internal Roads and Infrastructure (IRI) Directorate). Version 2.  Client and department details (i.e.0 Part 1 – Section 300 Page 4 of 21 November 2014 . etc.  Project Title.  Date.  Volume No. ROADWAY DESIGN MANUAL See Figure 300.: ………… Date: ………… ………… ………… Client Logo Prepared for: Section: ………… ………… Figure 300.01 below. which is to be used as the standard cover sheet for the DCR.0 Part 1 – Section 300 Page 5 of 21 November 2014 . Project Title: ……………………………………………………………… ……………………………………………………………… Project Location Plan Final Design Concept Report Volume I Preparer’s Logo Prepared by: Address: Project No.01 Standard Design Concept Report Cover Sheet Version 2. displacement of coastal vegetation) should be summarized. Both the major benefits (e. The project description should be very general and should identify the project’s location.  Recommended Design Concept. 304 TRAFFIC ANALYSIS All highway projects are subject to the approval of the DoT in terms of the traffic implications of the scheme.Section 203. project information is to be submitted to the DoT as an initial application. signal Version 2. As part of this process.  Alternatives Evaluated. This is an iterative process that results in identification of the number of through lanes. Traffic Data Collection.  Major or Controversial Issues. It should be clearly stated how the recommended design responds to the purpose and need of the project. improved traffic circulation.0 Part 1 – Section 300 Page 6 of 21 November 2014 .ROADWAY DESIGN MANUAL 302 EXECUTIVE SUMMARY The Executive Summary is a short (2-4 pages) recapitulation of the DCR document. and the source of funding that will be used for its design and construction. The Summary should address the following key topics:  Purpose and Need of the Project.g. It should only be a few paragraphs in length and should provide a brief description of the project as well as the reason for preparing the Design Concept Report. the agency/municipality in charge of its implementation. 303 INTRODUCTION The introduction is to prepare the reader for the subject matter that will follow in the body of the report. which will be used to establish whether a Transportation Impact Study (TIS) is required and if so. improved intersection safety) and the adverse impacts (e.  Estimated Cost. It is not necessary to address every aspect or technical consideration that is discussed in the main body of the report. the required extent of the study area. auxiliary lanes. This will also define the requirements for traffic counts. The summary should focus on items presented in the report that are of critical interest to ADM such as an accurate concise description of the recommended design concept and the estimated cost.03.  Conclusion. The data will be used to analyze and shape the various alternatives and geometrics. The collection of traffic data and the traffic projection procedures are discussed in Part 1 . A statement can also be included that identifies how the project fits into the overall transportation infrastructure of the area. turning lane requirements including storage lengths.g.  Controller Equipment.. etc. stationing. profile variations. The horizontal alternative alignments will be displayed on aerial photographs for evaluation of associated impacts. peak hour and peak hour directional splits and percentage of trucks. level of service and capacity. or an important justification.0 Part 1 – Section 300 Page 7 of 21 November 2014 . On all projects where the primary justification. proposed structures. The alternatives identified may include separate horizontal alignments. social. utilities and affected properties. The complete report shall also be included as a separate Appendix. For each signal location. Schematic diagrams of the roadway segments and intersections should be used to display the data. Estimates should be made of the accident reductions expected if the improvement proposal (or alternatives) is built. A summary of the traffic analysis shall be included in the body of the DCR. 305 DESCRIPTION OF ALTERNATIVES In consultation with ADM. A cost estimate will be prepared for each alternative and include: Version 2. the following information should be provided:  Phasing Diagram. Traffic signal recommendations will be included in the report.  Detection Requirements.  CCTV. of the project is to improve safety. at a scale that is appropriate to the project length and character. The sheets will show the proposed centreline. This information will be presented in the DCR along with a summary of the project traffic data including current and forecast ADT values.  Power Source. economic and natural environmental impacts for each alternative under consideration must be addressed. the DCR should include accident history data and an analysis of the causes of the accidents as well as a collision diagram. typical section concepts.ROADWAY DESIGN MANUAL warrants.  Interconnection. Note that traffic signals are the responsibility of the DoT and as such these proposals require the review and approval from DoT. The engineering. edge of pavement lines. The monetary value of the accident savings should be calculated over the design period of the project (normally 20 years where geometric improvements are proposed). the engineer shall develop alternatives to be evaluated that respond to the project purpose and need to varying degrees. that can be evaluated in a matrix form to qualitatively and quantitatively review the alternatives to identify major differences. shoulder width and bridge width on the project. meetings will be held with various Municipality and Government Departments that have a vested interest in the project. General Design Criteria. minimum sight distances (passing and stopping). The following basic design criteria established in Part 2 .  lane width. review the evaluation criteria and matrix form and discuss merits and adversities of the different alternatives. At this point.Section 100. Version 2.. horizontal/vertical curve radii. It is very important that sufficient detail is included in the DCR so that future revisions to basic design features and project scope are kept to a minimum. Comments and direction received at the meeting(s) will be factored into the alternatives evaluation matrix. sight distances (passing and stopping). the analysis will conclude with a discussion of the evaluation criteria for each matrix parameter.ROADWAY DESIGN MANUAL  Construction costs.0 Part 1 – Section 300 Page 8 of 21 November 2014 . This will be followed by the engineer’s recommended alternative with supporting justification for the selection. and.  horizontal and vertical alignment (actual). The design exceptions identified shall be prepared in a “Fact Sheet” format as described in Part 2 Section 100. General Information. shall be included:  the functional classification of the road. superelevation.  Land acquisition costs. maximum superelevation and other design requirements associated with the classification of the road. input/direction received concerning the project and a summary discussion of the advantages and disadvantages of each alternative studied. Finally. minimum horizontal/vertical curve radii.  bridge structural capacity.Roadway Design. used for the project.  the actual design speed(s).  horizontal and vertical clearance. 306 DESIGN DATA This section will document the design criteria associated with the recommended design concept and specifically identify any exceptions from the minimum criteria established for the roadway classification.  the minimum design speed(s). The engineer will present the alternatives. as per Part 1 . etc.  Utility relocation works costs.  cross slope and grade. auxiliary lanes. unless otherwise agreed with ADM.ROADWAY DESIGN MANUAL 307 TYPICAL SECTIONS The typical roadway cross sections and the dimensions of the lanes. volume. The plans are to be attached as an appendix to the DCR. The site considerations include:  Constraints imposed by the existing and nearby transportation facilities. The number of typical sections will depend on the number of significantly different roadway/pavement structure conditions.  Right of way controls. The project considerations include:  Speed.000 should be used for urban projects. constraints. shoulders. Version 2. and any retaining walls are also to be included. A scale of 1:1.  Community impact. i. profile. shoulders. Grade Separated Interchanges. The discussion in this section should identify the site and project considerations which led to the selection of the interchange and intersection type. and composition of traffic to be served.. including through lanes. ramps.  The number of intersecting legs. The type of roadway section.Section 500. The text in this section should include a narrative description of the geometrics. 308 GEOMETRICS The alignment. drainage considerations and reference to the design exceptions. and number of traffic lanes. etc. controlling factors.e.  Local planning. pavement structural section. cut or fill. Drawings that illustrate this information are to be included in the Appendix to the DCR. frontage roads. drainage channels. 309 INTERCHANGE / INTERSECTION CONFIGURATION The various types of traffic interchanges are described in Part 2 . cross slopes.).e.0 Part 1 – Section 300 Page 9 of 21 November 2014 . The alignment should be displayed on an aerial base and the corresponding roadway profile shown below in a split sheet format. and cost topography.. at least one section should be provided which depicts all facilities within the limits of the right-of-way (i. number of lanes. turning lanes and ramp lanes are to be plotted on an appropriately scaled plan.  The standards and arrangement of the local street system including traffic control devices.  Proximity of adjacent interchanges. median(s) for both the mainline and all ramps are to be identified. At a minimum.  Conceptual design of the recommended alternative (see Part 2 . This is especially true for freeway and urban expressway projects where the Interchange/Intersection type has a significant impact on the project character.  Resulting parking shortfall (or excess). when viable options are identified for the particular project.  If required by the roadway classification. Parking). Parking Requirements.  Anticipated parking demand.  Safety considerations.Drainage”.Section 305. which shall also include.02.Section 202. The Design Concept Report shall include a separate section (study) for drainage design concepts. 311 HYDROLOGY AND HYDRAULICS The requirements associated with hydrology and hydraulics can be found in the separate ADM publication “Roadway Design Manual . The summary of the results shall include:  Existing parking demand.  Alternatives as to how the project can provide adequate parking.  Cost. when required.  Costs and right-of-way requirements associated with each of the above alternatives. The results of the study shall be summarized in the body of the DCR. capacity and cost. Description of Alternatives.13. The interchange/intersection alternatives should be evaluated as a part of the alternatives analysis described in Part 1 . a parking study shall be prepared and included as part of the DCR.  Cost comparison of parking alternatives.  Recommended alternative to meet the anticipated parking demand.Section 211. the need for off-street parking facilities. separate reports for flood plain encroachment and major Version 2. 310 PARKING STUDY In accordance with Part 1 .  Economic impact of inadequate parking. Note that the requirements for parking should be in accordance with the latest guidelines published by the DoT and that all parking proposals shall be approved by the DoT.ROADWAY DESIGN MANUAL  Crossing and turning conflicts. with the entire study included in the Appendix.0 Part 1 – Section 300 Page 10 of 21 November 2014 .  Drainage map showing topographic features. and assumptions for analysis and design.0 Part 1 – Section 300 Page 11 of 21 November 2014 . The data will allow some basic judgments to be made.  Design criteria.  Proposed concepts for disposal of storm water. Geotechnical for more details).e. drainage areas. proposed cross-drain locations (including peak flow volume. In the case of either the structure borings or roadway borings. slope contours. i. sizes and peak flow volume)  Hydrology calculations for drainage area intercepted by the project to include peak runoff volume flow rates from each drainage area.  Recommended size and location of cross drainage structures and channels. This will be presented in an engineering report. The objective of the exploration program is to provide specific subsurface information along successive design sections or reaches of the project. methodology. design high water elevation and culvert size) and proposed conveyance systems (pipes and channels including flow direction. including design high water elevation that might affect the road profile grades or the roadway location. existing drainage systems.Section 700.  Assessment of existing and future conditions affecting drainage areas. and make geotechnical engineering recommendations using the field boring and lab test data. severity and extent of geotechnical design problems. prepared by the engineer for the project and included in the Appendix (refer also to Part 3 .  Proposed concepts for handling and disposing of storm water during construction. The Geotechnical Report will assemble the results of the subsurface exploration program. watershed boundary. and outfall locations. flow patterns. detention.  Bridge Location and Hydraulics Report for bridge or large box culvert waterway crossings.  Separate Flood Plain Study Report where the roadway encroaches on flood plains either longitudinally or transversely. the most suitable type(s) of foundations for structures and recommended pavement designs to be developed during the design phase. The results will be Version 2. the engineer will formulate a subsurface exploration and testing program.  Proposed concepts for on-site roadway drainage collection. procedures. analyze. horizontal and vertical alignment and structure requirements have been generally defined.ROADWAY DESIGN MANUAL waterway crossing studies. 312 SUBSURFACE INVESTIGATIONS Once the project location. the geotechnical program will serve to reveal the type.  Estimate of future development and its effect on flows and flood levels. The drainage design concepts section shall address the following items:  Planning consideration for the overall watershed considering the project and other existing and future development. and flood levels.  Analysis and preliminary recommendations for pavement structural section and foundations.  Preliminary and simplified analysis and computations – may need to be carried out to arrive at initial conclusions on selection of foundations and slope systems.  Physical and chemical soil stability testing and analysis.  The general description of the subsurface geological strata obtained from the soil borings. 313 BRIDGE TYPE SELECTION Selection of the most suitable type of structure involves investigating alternative superstructure. When performing the concept studies the following design objectives shall be considered as a minimum:  Safety  Serviceability - Version 2.  Preliminary assessment of safe slopes.  Selection of suitable foundation system alternatives.  Analysis and recommendations for embankment construction including settlement and surcharging.  Groundwater data.  A summary of the information obtained from and the location diagram of the soil borings.  Results of surface visual observations.ROADWAY DESIGN MANUAL summarized in the DCR. This is an iterative phase where assumptions must be made and later verified or modified during the design process. The report is to contain the following information:  Summary of previous geotechnical investigations.  Particle size analysis and potential for scour.  Description of the program undertaken to identify geotechnical and subsurface elements which affect project design. substructure and foundation types including variation of span length and structure depth to determine the best bridge type and arrangement for a particular site.0 Durability Part 1 – Section 300 Page 12 of 21 November 2014 .  Results of any material testing. Detailed design should not be performed at this stage unless it is necessary to confirm the adequacy of a concept.  Suggest ground improvement method and suitable alternatives. including any areas of unacceptable soil conditions. the following items should be investigated: Version 2. coordination with the project drainage requirements will be necessary. The geotechnical aspects of the site should be considered since the foundation type and associated cost may influence the type of bridge selected. vertical clearance. the channel width.Section 312.Section 321. Section 2.0 Part 1 – Section 300 Page 13 of 21 November 2014 . These requirements will be addressed in the discussion detailed in Part 1 . An initial (stage one) subsurface exploration and testing program will be performed in parallel as described in Part 1 . Construction Staging.3 – Design Process. The requirements for other stages are detailed in the ADM “Consultant Procedure Manual”.ROADWAY DESIGN MANUAL - Inspectability - Maintainability - Rideability - Utilities - Deformations - Consideration of Future Widening  Constructability  Economy  Bridge Aesthetics Plans and sketches should be made of the various alternatives investigated and included in the report. The above guidelines describe the process during the conceptual design stage. For navigable crossings. The designer should obtain the Initial Drainage Report and thoroughly review the contents before starting the analysis of alternatives. 313. which also includes the Project Submission Requirements Form (Table 2-1).01 BRIDGES OVER WATERWAYS For waterway crossings. Traffic requirements must be investigated including any detours or phasing requirements. Inadequate vertical clearance will necessitate a change in either profile grade or superstructure depth while inadequate horizontal clearance may necessitate a change in span length. and will be used to determine foundation type and costs. Both the vertical and horizontal clearances should be checked to ensure that adequate clearances are provided. Subsurface Investigations. pier protection and navigational aids should be investigated and agreed.02 WIDENINGS / REHABILITATION On projects involving widening. 313. in addition to the requirements for new bridges. approval by the Executive Council or higher authority will also be required. ecological and environmental demands of the project. Approximate costs based on preliminary quantities and unit costs associated with each solution will be required. and should thoroughly discuss the factors that influenced the selection of the preferred alternative. and also the requirements specified in the various sections of Part 3 – Structure Design. and sociological.  The condition of existing diaphragms on steel girder bridges.03 BRIDGES AND HIGHWAY STRUCTURES CONCEPT REPORT The Bridges and Highway Structures Concept Report is prepared in the concept design phase. For large or sensitive projects. vertical and horizontal clearances. location.  The existing waterway opening. A complete discussion of the costs and feasibility of alternate designs must be included. Ultimately. Through these discussions a structure with architectural features that are compatible with structural.  The condition of the existing deck joints  The condition of the existing bearings.  The adequacy of existing bridge rail.  The existing foundations. This should include the following structural considerations:  Foundation Type  Substructure Version 2.0 Part 1 – Section 300 Page 14 of 21 November 2014 . 313. Bridge Type Selection. These plans reflect the bridge geometrics. When the above items have been investigated. Possible alternatives include: widening to one side.  The need for adding approach slabs. Generally three or more alternative conceptual structural solutions should be assessed. safety and site requirements can be developed. based on the criteria listed in Part 1 .ROADWAY DESIGN MANUAL  The existing structure should be checked for structural adequacy. substructures and types of foundations.Section 313. The results of the bridge type selection process will be summarized in the DCR. concept design can proceed by studying alternatives. The completed Bridges and Highway Structures Concept Report shall include general conceptual plans of the bridges proposed on the project. These may be individual or joint discussions as dictated by the size. complexity. architectural themes. describing the structural design options considered and summarizing the findings of the geotechnical and initial drainage studies. widening symmetrically on both sides or replacing the bridge with a new structure. one of these options should be recommended for ADM approval. economical. This is especially important for unusual and major structures. The preliminary choice of tunnel type. The “Technical Manual for Design and Construction of Road Tunnels .02 below: Planning / Route Selection Water Immersed Tunnel Rock Tunnel Land Bored Tunnel Soft Ground Tunnel Difficult Ground Tunnel Cut and Cover Tunnel SEM Tunnel SEM : Sequential Excavation Method Figure 300.Civil Elements”. These are cut-andcover. The General Plan shall be included in the Drawings (A3 size) that will accompany the DCR. Publication No.ROADWAY DESIGN MANUAL  Superstructure  Architectural Features  Vertical and Horizontal Clearance  Other Key Factors (as specified in the relevant checklist in the ADM “Quality Control and Quality Assurance Procedures” manual). soft ground tunnels. US Department of Transportation Federal Highway Administration. rock tunnels. immersed tunnels and jacked box tunnels. bored or mined tunnels. 314 TUNNEL SELECTION CRITERIA There are a number of principal types and methods of tunnel construction. December 2009 provides details and uses of the different type of tunnels.02 Preliminary Road Tunnel Type Selection Process The final selection of a tunnel type depends on the geometrical configurations. as illustrated in Figure 300.0 Part 1 – Section 300 Page 15 of 21 November 2014 . the anticipated ground movements Version 2. the ground conditions. FHWA-NHI-10-034. the type of crossing. depth of cover to the tunnel. can be dictated by the general ground conditions. during the conceptual design stage. ROADWAY DESIGN MANUAL during construction and environmental requirements. Determining the suitable type of tunnel at selected locations will depend on. economical. profile and cross section. the following:  Defining the functional requirements. Tunnel alternatives shall also be included in the Bridges and Highway Structures Concept Report. risk and environmental assessments and recommendations. The DCR will include a thorough discussion of the utility impacts and a tabulation of the existing utility inventory as follows:  Item Number Version 2. it is important to perform the tunnel type study as early as possible in the planning process and select the most suitable tunnel type for the particular project requirements. Therefore. Design Concept Development. geotechnical and geohydrological data. the location of service reservations will affect the roadway geometrics including parking areas. For urban projects.Section 200. The choice of tunnel type requires the approval of ADM. results of geotechnical assessment.  Evaluation of available investigations including geological. available and additional investigations.  Outcome of risk analysis and associated mitigation measures to identify construction and long term risks. This should include information used to confirm tunnel options considered. The Consultant should take additional care to ensure that proposed tunnels do not impact negatively on existing structures in the vicinity of the project. including design life and durability requirements. complexity. green areas and the proposed pavement surfacing. but not be limited to. Utility corridors including proposed Service Reservations should be identified and indicated on the typical sections and roadway plans included in the DCR. The level of necessary approvals will be dictated by the size. sociological. The assessment should include conceptual structural arrangements. cultural and institutional studies.  Tunnel alignment. 315 UTILITY IMPACT ANALYSIS Utility impacts are a key project issue. Additional analysis should be conducted to ensure that any proximity or interface with such structures does not impart any detrimental effect. ecological and environmental demands of the project. especially within existing transportation corridors. location.  Evaluation of the environmental.0 Part 1 – Section 300 Page 16 of 21 November 2014 . The second phase of work includes analysis of the existing and proposed utilities with respect to each alternative in order to permit estimation of costs and evaluation within the alternatives matrix. Data collection and coordination with the various agencies/departments is discussed in Part 1 . Associated utility costs will be included in the concept cost estimate. as per the requirements described in Part 1 .0 Part 1 – Section 300 Page 17 of 21 November 2014 . sewer. if not relevant. Primarily. ADM shall make a determination as to the relevance of the topic based on this information. Environmental Factors Influencing Design. shall be included in the DCR. The Technical Memorandum and supporting documentation is to be included as a separate appendix in the DCR. The responsibility for design and construction of the facilities will be addressed. Each of the topics covered in the abovementioned section shall be included or. etc). 317 AGRICULTURE IMPACT Agricultural resources are important to man’s survival and therefore must be preserved to the greatest extent possible. The above information may also be obtained from the Environmental Impact Assessment Report.ECONOMIC ANALYSIS An analysis and discussion of the socio economic data. Recommendations will be given for general utility relocation schemes and for resolution of specific utility conflicts. The required information as to the reasons why topics are not relevant shall be summarized in a concise Technical Memorandum accompanied by supporting documentation as necessary. Reference shall also be made to the latest version of the UPC “Utility Corridors Design Manual” (UCDM) for further guidance. For any of the topics which are not relevant. The Consultant shall identify the potential impact that the proposed project alternatives may have on these resources within the study area. where applicable. prior approval from ADM is required to exclude the issue from the DCR.Section 202. For larger projects a separate Utility Report should be prepared and included as an Appendix to the DCR.ROADWAY DESIGN MANUAL  Owner  Description  Station  Location  Status  Remarks The DCR will summarize the impacts for each major utility (water. electrical. Schematic plans showing the major existing and proposed utilities should be prepared and included in the drawings section. this involves Version 2. irrigation. telephone. 316 SOCIO . it should be so stated including the reason why it is not relevant. These may include. workshops and consensus building sessions. 318 PUBLIC FEEDBACK Public involvement is an important aspect in the overall success of a project. The signing requirements shall be displayed on a reduced scale version of the project geometrics sufficient to show the required detail. the plan will also provide the public with the opportunity to comment at various stages of project development. and whether or not consensus has been reached. The signing and lighting concept plans will be included in the drawings section of the DCR. The above information may also be obtained from the Environmental Impact Assessment Report. In the description of impact. including the location and scheduling of public information meetings. A summary of the primary issues raised by the public should be presented along with a discussion of how these issues have been addressed during the development of the project. the Consultant shall identify whether the land is actively farmed or fallow as well as the types of crops that would be affected. Impacts will be quantified in hectares. In addition to keeping the public informed of the project. This section of the DCR should briefly describe the elements of the Public Information Plan. Version 2. Impacts associated with each project alternative will be compared and the alternative with least agricultural impact shall be identified if such an alternative exists. It may be necessary to include signing outside of the project limits. Indirect impacts will also be identified and described. Proposed guide signs should be illustrated graphically with arrows pointing to the sign location. 319 SIGNING AND PAVEMENT MARKINGS Signing concept plans will be developed to show the major guide signs required for the proposed facility in accordance with the ADM “Traffic Control Devices Manual”. Signing requirements associated with the construction staging/detour scheme should also be discussed. the consultant shall develop a Public Involvement Plan that will establish the approach to be used to coordinate project planning and details with the public. New signs or modifications required to existing signs shall be clearly identified. where applicable. the Consultant is more likely to produce a design that is economically feasible and acceptable to the public.ROADWAY DESIGN MANUAL determining whether or not the project will directly impact (i. By soliciting and actively considering public input. but are not limited to. A file should be maintained as backup for each public meeting that contains a list of participants and the issues raised.e. the potential disruption of the existing irrigation system or pollution of nearby agricultural lands from untreated stormwater runoff. At the onset of the project.0 Part 1 – Section 300 Page 18 of 21 November 2014 . irreversibly commit) land that is presently used for agricultural purposes. or any other forums aimed at soliciting public input. ROADWAY DESIGN MANUAL 320 LIGHTING CONCEPTS This section should begin with a discussion of the design criteria that governs the location of lighting. the type of lighting relevant to the roadway classification or route and the method of illumination analysis. consistent with the Standard Specifications. In accordance with the “Urban Work Zone Traffic Management Manual”. markings and signing are to be submitted at the relevant design stages and pre-construction stage to the Abu Dhabi Road Safety Unit (RSU) and Traffic Services Section (TSS) for review and approval. and the compatibility with adjacent or intersecting lighting system will be shown and illustrated on schematic plans. Similar forms must be developed for each bill section to back-up the summary. In some instances. The DCR shall include a discussion as to how construction of the project will be staged including:  Number of Stages  Erection of Falsework  Anticipated Detours  Duration of each Stage The final design plans will generally be prepared in conformance with staging described in the DCR. 321 CONSTRUCTION STAGING Maintenance of traffic during construction can have a significant effect on the surrounding traffic system. Applicability or conformance to existing Master Lighting Plans must be considered. cost and the duration of construction.0 Part 1 – Section 300 Page 19 of 21 November 2014 . not all of the items can be identified at this stage and an appropriate contingency factor should be applied to reflect possible increases such as modification of the project limits or adding decorative features. in terms of public convenience. Version 2. including the estimated quantities and unit prices. traffic management plans. 322 COST ESTIMATE The DCR concept cost estimate must be as realistic and accurate as possible. This is intended to standardize the format and type of items that need to be considered in the project.03) to summarize the individual bills. The degree of effort and detail for each project is expected to vary depending upon the complexity and sensitivity of the project-related issues. Alternative types of lighting such as high mast at major interchanges should also be addressed. design. work zone practices. The typical spacing between light sources. It is important that all known items of work be identified and estimated. The concept cost estimate should be prepared using the “Concept Project Cost Estimate” form (Figure 300. 03 Cost Estimate Worksheet Version 2. Figure 300.0 Part 1 – Section 300 Page 20 of 21 November 2014 . BILL DESCRIPTION Dh I GENERAL II EARTHWORKS III SUBBASE AND BASE COURSES IV ASPHALT WORKS V CONCRETE WORKS VI STORM WATER DRAINAGE SYSTEM VII WATER WORKS VIII PRESTRESSED CONCRETE WORKS IX TRAFFIC MARKINGS AND SIGNS X SITE LABORATORY XI CONCRETE PILE FOUNDATIONS XII METAL WORKS XIII POST-TENSIONED CONCRETE XIV EXPANSION AND FIXED JOINTS XV IRRIGATION WORKS XVI LIGHTING AND ELECTRICAL DISTRIBUTION WORKS XVII TRAFFIC CONTROL SYSTEM XVIII DAILY WORKS SCHEDULE XIX TELEPHONE WORKS XX SEWERAGE WORKS XXI STREET FURNITURE XXII SOFT LANDSCAPING XXIII HARD LANDSCAPING XXIV ARCHITECTURAL WORKS Fs TOTAL ESTIMATED COST Note: Enabling works to be included in Bill No.ROADWAY DESIGN MANUAL CONCEPT PROJECT COST ESTIMATE SUMMARY OF BILLS OF QUANTITIES AMOUNT IN FIGURES BILL NO. II – Earthworks. and their associated costs. 324 APPENDIX This section will be used for appending Technical Memorandums and the complete detailed studies or reports as directed by ADM.  Roadway Plan/Profile.  Pavement Design Report. recommendations.  Initial Drainage Report.  Parking Study. The drawings should include the following:  Typical Sections.  Architectural Renderings.  Lighting Report.  Structure/Bridge/Tunnel General Plans. Version 2.  Construction Staging Schematics.Design Exceptions.  Alternatives.  Bridges and Highway Structures Report.  Traffic Analysis Report.  Other project specific plans as require. Examples of these are as follows:  Utilities Report.  Signing and Lighting Concept Plans.0 Part 1 – Section 300 Page 21 of 21 November 2014 .  Geotechnical Report.ROADWAY DESIGN MANUAL 323 CONCLUSIONS / RECOMMENDATIONS This section will include conclusions. The name and title of the Project Engineer responsible for the preparation of the DCR as well as the Abu Dhabi City Municipality’s Engineer who served as the ADM Representative shall also be indicated.  Fact Sheet .  Utilities. 325 DRAWINGS The drawings prepared to illustrate and define the design concept should be presented in A3 format as Volume II of the written report which is bound separately in A4 format.  Drainage. ROADWAY DESIGN MANUAL PART 2 – ROADWAY DESIGN Version 2.0 Part 0 – Divider November 2014 . 0 Part 0 – Divider November 2014 .ROADWAY DESIGN MANUAL SECTION 100 : GENERAL DESIGN CRITERIA Version 2. retaining walls. Where a reason for limiting speed is obvious to approaching drivers or cyclists. Version 2. horizontal alignment and sight distance. Examples include partial or brief horizontal sight distance restrictions. environmental or other considerations make it impractical to provide the minimum elements established by the design speed. However. a roadway with a design speed of 120 kph would normally have a posted speed of 100 kph.GENERAL DESIGN CRITERIA 101 DESIGN SPEED Design speed establishes specific minimum roadway design criteria. The design speed for any section of roadway should be a constant value. economic considerations. In addition. as high a design speed as practical should be used.0 Part 2 – Section 100 Page 1 of 20 November 2014 . economic. Subject to the above considerations. during design. In addition. cut slopes and median barriers. The design elements influenced by design speed include vertical alignment. the driver crossing the open desert expects the operating speed (normal travel speed) to be similar for a divided road or a two-lane roadway. Design speed relates indirectly to other elements such as pavement and shoulder width. cycling and walking can be encouraged when cyclists and pedestrians perceive an increase in safety due to lower design speeds. roadway functional classification and adjacent land use.ROADWAY DESIGN MANUAL PART 2 .ROADWAY DESIGN SECTION 100 . and horizontal clearance. Drivers expect consistent design speeds for adjacent roadways or roadways with similar characteristics. However. particularly where the savings in vehicle operation and other costs are sufficient to offset the increased cost of right-of-way and construction. Normally. they are more apt to accept a lower operating speed than where there is no apparent reason for it. Drivers and cyclists adjust their speed based on their perception of the physical limitations of the highway and its vehicular and bicycle traffic. The posted speed limit (posted speed) is a function of the design speed and is usually specified as one step below the design speed. Design speed is influenced by terrain. situations may arise in which engineering. like those imposed by bridge rails. Hence. environmental factors. Further. bridge columns. a lower design speed should not be assumed for a secondary road where the topography is such that drivers are likely to travel at high speeds. A roadway carrying a large traffic volume may justify a higher design speed than a less important facility in similar topography. the selected design speed should be consistent with the operating speeds that are likely to be expected on a given roadway. type and volume of traffic. the design speed difference between adjacent segments should not exceed 10 kph. A driver in a mountainous area would expect to travel more slowly than a driver crossing the open desert. sound walls. 01 below. refer to Part 2 .ROADWAY DESIGN MANUAL The cost to correct such restrictions may not be justified. are shown in Table 100. Design speed may be lowered. For further information on the above design vehicles.01 DESIGN SPEEDS FOR URBAN ROADS Location Classification Typical Number of Lanes Posted Speed (kph) Design Speed (kph) Boulevard 3+3 60 80 Avenue 2+2 40 . Design vehicles applicable to the USDM street family descriptions are provided below in Table 100.02 DESIGN VEHICLE TYPES Roadway Classification Urban Roads Rural Roads Boulevard Freeway Avenue Expressway Street Collector Access Lane Access Road Primary Secondary Design Vehicle WB-12 Single Unit Bus/Truck (SUM) * Local Note: *City-Bus M for streets with designated public bus routes. Table 100.02. Desirable design speeds.50 60 Street 1+1 30 40 Access Lane 1+1 20 30 Freeway 4+4 120 140 Expressway 3+3 80 / 100 100 / 120 Collector 2+2 60 / 80 80 / 100 Access Road 1+1 40 / 60 60 / 80 Urban Rural 102 DESIGN VEHICLES Design vehicles represent the vehicles which must be regularly accommodated at junctions without encroachment into the opposing traffic lanes. Technically. Such technical reductions should be discussed and carefully considered before being accepted. Version 2. Table 100. especially in densely developed urban areas.0 Part 2 – Section 100 Page 2 of 20 November 2014 . this will result in a reduction in the effective design speed at the location in question. Design speeds applicable to special projects will be established by ADM. as related to roadway classifications.Section 405 of this manual. Character of the traffic. as a percentage of the DHV (excluding recreational vehicles). control vehicles and non-motorised vehicles.02 RELATION TO DESIGN The design designation is a simple. or (b) A decided change in topography dictates a change in design speed. 103. Refer to the USDM for further details. Within a project. rehabilitation and operational improvement projects should be designed using current traffic volumes. Two-way Design Hourly Volume (vehicles). with consideration for future growth. depending on specific project requirements. resurfacing. The following is an example of this expression: ADT (2015) ADT (2035) DHV where: ADT (2015) ADT (2035) DHV D T = = = = = V = = 9. one design designation should be used except when: (a) The design hourly traffic warrants a change in the number of lanes. Design speed (kph).000 = 3. 103 DESIGN TRAFFIC 103. Average Daily Traffic (vehicles) for the target future design year. Version 2. unless otherwise directed by ADM. restoration. Safety. including speed control vehicles. This is expressed by the truck increment (T).0 Part 2 – Section 100 Page 3 of 20 November 2014 .01 DESIGN PERIOD Geometric design of new facilities should be based on estimated traffic 20 years after completion of construction.800 = 20.000 D = 60% T = 12% V = 110 kph Average Daily Traffic (vehicles) for the construction year. Percentage of the DHV in the direction of the heavier flow. concise expression of the basic factors controlling the design of a given roadway.ROADWAY DESIGN MANUAL Other design vehicles may also need to be considered. The design designation should appear on the typical cross section for all new roadway construction projects.  Volumes of trucks. Broadly defined.01 Introduction Design capacity is the maximum volume of traffic for which a projected roadway can provide a selected level of service. LOS A. LOS B indicates reasonable free flow. The highest feasible LOS should be selected and used for design. LOS D is considered as the limit of acceptable urban area operation and remedial works would be needed if this is not met.  Side friction generated by parking.01 DESIGN CAPACITIES (VEHICLES) 104. Design capacity varies with a number of factors. except where unreasonable costs or environmental constraints would dictate a lower LOS. in terms of traffic flow. LOS E is unstable flow.  Weaving sections. LOS D is the lower range of stable flow. recreational vehicles. and LOS F indicates forced flow.  Percentage of trucks.03.  Lateral clearance.01. LOS C is stable operation. including:  Level of service selected. design year traffic and operation at a specified level of service (LOS). buses.  Shoulder width (if present). For operational analysis. intersections and interchanges. driveways. For planning applications.02 LOS Definitions for Urban Roads LOS definitions for urban roads are given in Table 100.ROADWAY DESIGN MANUAL 104 ROADWAY CAPACITY 104. 104. buses and recreational vehicles. The worst of the average speeds and volume/capacity (v/c) ratio should be used to determine the LOS.  Width and number of lanes.0 Part 2 – Section 100 Page 4 of 20 November 2014 . is desirable. LOS A is associated with free flow traffic.  Operating speed. based on posted speed limits.  Spacing and timing of traffic signals.01.  Horizontal alignment. Design levels of service for various conditions are shown in the following tables. Design capacity is based on the factors above. Version 2. bicycles and pedestrians.  Grades. 0.20 15 .23 E 35 .04 LOS Definitions for Freeway and Multi-Lane Rural Roads Level of Service (LOS) Measure of Performance Freeway Density (pcpkpl) Multi-Lane Rural Roads Density (pcpkpl) A 0-7 <8 B 7 .56 28 .9 .0 F < 26 < 17 < 14 > 1.18 0. although LOS D may be acceptable on recreational routes and where weekend peaks are the defining movements.25 F > 50 > 25 Source: Abu Dhabi TIA Guidelines.7 C 40 .06 below and are based on the link density as measured in terms of passenger cars per kilometre per lane (pcpkpl).0 Source: Abu Dhabi TIA Guidelines.ROADWAY DESIGN MANUAL Table 100.15 8 . Version 2.05 and 100.04 LOS Definitions for Merge / Diverge and Weaving Sections The LOS definitions for merge/diverge and weaving segments are given in Tables 100. DoT 104.6 B 56 .40 22 . This is based on link density as measured in terms of passenger cars per kilometre per lane (pcpkpl). LOS C is desirable. LOS D is acceptable for both planning and operational applications. In rural areas.03 LOS Definitions for Freeway and Multi-Lane Rural Roads The LOS definitions for links are given in Table 100.32 17 .0 .39 23 .01.41 0.15 C 15 .6 .8 D 32 . LOS D is acceptable for both planning and operational application in urban settings.0.20 D 20 .23 0.22 14 .32 0.9 E 26 .01.04.7 .72 39 .03 LOS Definitions for Urban Roads Measure of Performance Level of Service (LOS) Average Speed (kph) Arterial Collector Local Volume/Capacity (v/c) Ratio A > 72 > 50 > 41 0.50 32 .28 18 .1.0.0. Table 100.8 .50 23 . DoT 104.35 20 .0 Part 2 – Section 100 Page 5 of 20 November 2014 . an intersection LOS E is acceptable within the CBD with no individual movement operating worse than LOS E.0 Part 2 – Section 100 Page 6 of 20 November 2014 .ROADWAY DESIGN MANUAL Table 100.20 - D 20 .05 LOS Definitions for Merge / Diverge Sections Level of Service (LOS) Measure of Performance Density (pcpkpl) Number of Stops before Clearing A 0-7 - B 7 .22 E 22 . DoT 104.05 LOS Definitions for Signalised Intersections LOS definitions for signalised intersections are given in Table 100.07. The LOS is based on delay. intersection capacity utilisation and v/c ratio. DoT Table 100.27 F > 27 Source: Abu Dhabi TIA Guidelines.01.12 C 12 . However. At a planning level.15 - C 15 . LOS D is considered as the threshold in urban areas.50 3-4 F Demand exceeds capacity Source: Abu Dhabi TIA Guidelines.06 LOS Definitions for Weaving Sections Level of Service (LOS) Measure of Performance Density (pcpkpl) A 0-6 B 6 . Whichever parameter shows the worst conditions determines the LOS to be used.17 D 17 .35 1-2 E 35 . at an operational level. Version 2. 8 .20 0.0.0.73 . delay at intersections and percentage of hindrance.0. DoT 104.1.10 0.7 .91 .15 0. Table 100.0.6 .0.0 .55 B 10 .64 C 15 .01.00 – 0.9 E 55 .7 .01.00 Source: Abu Dhabi TIA Guidelines. DoT 104.64 .7 C 20 .0 F > 80 > 1.0.7 0.1.0.50 0.ROADWAY DESIGN MANUAL Table 100. LOS D is an acceptable threshold for priority intersections and roundabouts.0 Part 2 – Section 100 Page 7 of 20 November 2014 . The capacity of a cycle facility depends on the number of effective lanes used by cycles.6 B 10 .9 . LOS A should be considered acceptable for planning and operational analysis using any of the above measures of performance criteria.82 E 35 . The LOS is based on stopped delay and intersection capacity utilisation.8 D 35 .06 LOS Definitions for Priority Intersections and Roundabouts LOS definitions for priority intersections and roundabouts are given in Table 100.55 .55 0.0.8 .80 0.07 LOS Definitions for Signalised Intersections Measure of Performance Level of Service (LOS) Delay (seconds) Intersection Capacity Utilisation Volume/Capacity (v/c) Ratio A 0 .08. Version 2.73 D 20 .09.91 F > 50 0.07 LOS Definitions at Cycle Facilities LOS definitions at cycle facilities are given in Table 100.0 Source: Abu Dhabi TIA Guidelines.6 .0.20 0.6 0.82 .0 .1.9 0.35 0. The performance measuring criteria include speed.9 .35 0.0 > 1.10 0.8 0.0.0.0.0 0.08 LOS Definitions for Priority Intersections and Roundabouts Measure of Performance Level of Service (LOS) Stopped Delay (seconds) Intersection Capacity Utilisation A 0 . ROADWAY DESIGN MANUAL Table 100.09 LOS Definitions for Cycle Facilities Measure of Performance Level of Service (LOS) Delay at Intersections (seconds) Uninterrupted Flow (% of hindrance) Speed on Urban Street (kph) A < 10 < 10 22 B > 10 - 20 > 10 - 20 14 - 22 C > 20 - 30 > 20 - 40 11 - 14 D > 30 - 40 > 40 - 70 8 - 11 E > 40 - 60 > 70 - 100 6-8 F > 60 100 <6 Source: Abu Dhabi TIA Guidelines, DoT 104.01.08 LOS Definitions for Pedestrian Facilities LOS definitions for pedestrian facilities are given in Table 100.10. Pedestrian service standards are based on the freedom to select normal walking speeds, the ability to pass slow moving pedestrians and the relative ease of cross and reverse flow movements at areas of pedestrian concentration. The LOS criteria are based on delay experienced at intersections, density, speed and flow rate. LOS A is considered desirable for planning and operational analysis using any of the above measures of performance criteria. Table 100.10 LOS Definitions for Pedestrian Facilities Measure of Performance Level of Service (LOS) Delay at Intersections (seconds) Density (sqm/ped) Speed (m/s) Flow Rate (ped/m/minute) A < 10 > 3.3 1.33 23 B > 10 - 20 2.3 - 3.3 1.30 23 - 33 C > 20 - 30 1.4 - 2.3 1.20 33 - 49 D > 30 - 40 0.9 - 1.4 1.10 49 - 66 E > 40 - 60 0.5 - 0.9 1.00 66 - 82 F > 60 > 0.5 0.50 > 82 Source: Abu Dhabi TIA Guidelines, DoT Version 2.0 Part 2 – Section 100 Page 8 of 20 November 2014 ROADWAY DESIGN MANUAL 104.01.09 LOS Definitions and Standards for Public Transportation Services LOS definitions for public transport services are given in Table 100.11. The LOS is based on service frequency, headway and temporal coverage of the public transport services. LOS B should be considered acceptable for planning and operational analysis using any of the above measures of performance criteria. Table 100.11 LOS Definitions for Public Transportation Services Level of Service (LOS) Measure of Performance Frequency (vehicles/hour) Headway (minutes) Span of Service (hours) A > 6.0 < 10 19 - 24 B 4.0 - 6.0 10 - 14 17 - 18 C 3.0 - 4.0 15 - 20 14 - 16 D 2.0 - 3.0 21 - 30 12 - 13 E 1.0 - 2.0 31 - 60 4 - 11 F < 1.0 > 60 0-3 Source: Abu Dhabi TIA Guidelines, DoT 105 CONTROL OF ACCESS 105.01 GENERAL Control of access is achieved by limiting the number and location of roadway access points so that the through traffic capacity or safety of the facility will not be significantly impaired. There are three degrees of access control: Full Access Control - Gives preference to through traffic by providing access only through selected frontage/local roads and by prohibiting at-grade crossings or direct access from abutting property. Partial Access Control - Still gives preference to through traffic but permits some at-grade crossings and some private driveway connections. Approach Road and Driveway Regulations - Without access control, abutting properties are permitted access to the roadway, but the number, location and geometrics are regulated. Version 2.0 Part 2 – Section 100 Page 9 of 20 November 2014 ROADWAY DESIGN MANUAL Table 100.12 CONTROL OF ACCESS BY ROAD TYPE Location Road Classification Access Control Level Boulevard Partial Access Control Avenue Urban Avenue Approach Road and Driveway Regulations Access Lane Freeway Full Access Control Expressway Rural Full or Partial Access Control Partial Access Control Collector Access Road Approach Road and Driveway Regulations All roadways will have some degree of access control. The appropriate degree of access control by roadway type is given in Table 100.12. More detailed guidelines for establishing the control of access lines by roadway classification are presented in the following section. 105.02 105.02.01 ACCESS CONTROL DESIGN CRITERIA Primary Roadways The number of access openings on primary roads with access control should be kept to a minimum. Plots which have access to another frontage or local road as well as primary road frontage are not allowed primary road access. In some instances, plots fronting only on the primary road may be given access to another local road by constructing suitable connections, if such access can be reasonably provided. With the exception of extensive primary road frontages, access openings are limited to one opening per plot. Wherever possible, one opening should serve two or more plots. In the case of a large primary road frontage under one ownership, the feasibility of limiting access to one opening may be prohibitive, or the property may be divided by a natural physical barrier such as a wadi or ridge, making it necessary to provide an additional opening. However, in the latter case, it may be preferable to connect the physically separated portions with a low-cost structure or road rather than permit two openings. Access rights shall be acquired along interchange ramps to their junction with the nearest public road, and shall extend to the end of the ramp taper (or at least 50m beyond the end of the kerb return or ramp radius). Version 2.0 Part 2 – Section 100 Page 10 of 20 November 2014 ROADWAY DESIGN MANUAL In remote areas, infrequent access should be accommodated by providing locked gates. This will only be considered for areas that are remote, infrequently used and have no other means of access. Direct access must not be provided if it creates an unsafe condition. Turning movements will be limited to right turns only and written approval must be granted by ADM. 105.02.02 Secondary Roadways (ADT > 2,500) In general, the number of access openings shall be kept to a minimum for any facility. Additional access may be necessary to satisfy a range of design issues and access requirements. The following is a list of issues to consider when providing access points: (1) Emergency vehicles shall have a right to direct roadway access. (2) Private direct roadway access shall be permitted only when the property in question has no other reasonable access to the local road system. (3) If feasible, plots fronting only on the roadway shall be given access to another public road by constructing suitable connections. (4) Roadway access openings are limited to one per plot. Exceptions may be considered if they do not affect roadway safety or operation and they are necessary for safe and efficient property use. (5) In certain cases, a natural physical barrier such as a wadi or ridge may divide the plot. In this case additional access openings may be warranted. However, it may be preferable to connect the physically separated portions of the plot with a low cost structure or road rather than permit multiple access openings. (6) Wherever possible, one access opening should serve two plots. (7) When the number of required access openings on one side of a divided roadway exceeds three in 400m, a frontage/local road shall be provided. See Section 105.03, Use of Frontage Roads, for further information. (8) Access openings on divided roadways shall not be permitted within 100m of a median opening, unless the access opening is directly opposite the median opening. (9) Access approaches shall be limited to right turns only unless: (1) the approach has no signalization potential and allowing left turns would significantly reduce congestion and safety problems at a nearby intersection; or (2) there are no intersections, existing or planned, that allow a U-turn; and (3) left turns can be safely designed without signalization. (10) Access approaches with signalization potential and that require left turn movements must: (1) meet the signalization requirements of the concerned authority, and (2) shall not interfere with the location, planning, or operation of the general road system and nearby property access. 105.02.03 Secondary Roadways (ADT < 2,500) The primary function of these roadways is to provide reasonable and safe access to abutting property. Access needs generally take priority over through traffic as long as roadway safety is not compromised. Control of access is not obtained, but the location, number and geometric layout of Version 2.0 Part 2 – Section 100 Page 11 of 20 November 2014 ROADWAY DESIGN MANUAL access points must meet the following criteria: (a) The number of access approaches to a plot shall be controlled by safety and design considerations and shall be separated by at least the stopping sight distance. (b) For safety reasons, frontage roads or parallel service roads are not permitted along two-lane roadways because this results in the appearance of a divided roadway. (c) Left turns, if safety and design standards are met. (d) In urban areas with signalized intersections, the minimum spacing between access points shall be that which is necessary for the safe operation and proper design of intersections as specified in Section 400, At Grade Intersections (Junctions). 105.03 (1) USE OF FRONTAGE ROADS General Policy (a) Frontage roads are provided to:  Control access to the primary road, thus increasing safety.  Provide access to sectors.  Maintain continuity of the local road system.  Provide for non-motorized traffic that might otherwise desire to use the primary road. (b) Typically a frontage road is justified if the construction cost is less than the cost of providing other direct access. Right-of-way considerations are often the determining factor. Thus, a frontage road would be justified if the investment in construction and extra right-of-way is less than either the severance damages or the cost of acquiring the affected property. Frontage roads may be required to connect parts of a severed property or to serve a landlocked plot resulting from right-of-way acquisition. (c) Direct access to the primary roads. However, when the number of access openings on one side of the primary road exceeds three in 500m, a frontage road should be provided. (2) New Alignment - Local roads are generally not provided on new primary road alignments, since the abutting property owners never had legal right of access to the new facility. They may be provided, however, on the basis of considerations mentioned above. (3) Existing Alignment - Where a primary road is developed parallel to an existing roadway or local road, all or part of the existing roadway is often retained as a frontage or local road. Frontage roads must be constructed to serve landlocked remainders or the remainders must be purchased outright if other means of access cannot be provided. The decision whether to provide access or purchase should be based on considerations of cost, right-of-way impacts, road system continuity and similar factors to those discussed above. Version 2.0 Part 2 – Section 100 Page 12 of 20 November 2014 ROADWAY DESIGN MANUAL (4) National Railway or Abu Dhabi Metro Rail System Crossings - Frontage roads either side of a freeway or expressway on new alignment, owing to safety and costs factors, frequently are terminated at the railway right-of-way. When terminating a frontage road at the railway crossing, bicycle and pedestrian traffic still needs to have reasonable access through the community. New railway level crossings and grade separations, and any relocation, alterations of existing crossings must be cleared with the relevant authorities. (5) Frontage Roads Financed by Others - Frontage roads which are not an ADM responsibility under this policy may be built by the ADM upon request of a local political subdivision, a private agency, or an individual. Such a project must be covered by an agreement under which the ADM is reimbursed for all construction, right-of-way and engineering costs involved. 105.04 PROTECTION OF ACCESS RIGHTS Access Control lines/limits shall be shown on the project right-of-way plans. Where possible, the right-of-way line and control of access line should be coincident. For proper control of access, fencing or other approved barriers shall be installed on all controlled access roadways, located on the control or access line where appropriate. 105.04.01 Relation of Access Opening to a Median Opening Access openings should not be placed within 100m of a median opening, unless the access opening is directly opposite the median opening. 105.05 MAINTAINING LOCAL COMMUNITY ACCESS When planning and designing a new primary road, the designer needs to consider the impacts of an access controlled facility on the local community. Closing local road connections may negatively impact on access for pedestrians, cyclists and equestrians. A new facility may inadvertently sever local non-motorized access creating long, out of direction travel. Designers need to coordinate with local agencies for access needs across an access controlled facility. 105.06 PEDESTRIAN FACILITIES 105.06.01 General Policy Pedestrians, unless restricted by law, are allowed to use conventional highways and some primary roadways for transportation purposes. Connections between different modes of travel should be considered when designing highway facilities, as all people may need to walk to a transit-based facility. Design guidance associated with pedestrian facilities is as follows:  Ensure walkways are free from unnecessary obstacles and clutter. Version 2.0 Part 2 – Section 100 Page 13 of 20 November 2014 ROADWAY DESIGN MANUAL         Ensure no stepped changes in level. Wherever feasible, adopt walkway crossovers with pedestrian ramps and dropped kerbs at residential driveways to provide continuous walkways. Do not locate utility equipment at ground level – relocate wherever feasible. Use inset covers to integrate utility inspection covers/chambers with the pedestrian surface. Any building features (such as ventilation shafts, special lighting, sign boards, etc.) shall not obstruct pedestrian routes. Primary sidewalks/walkways should be 60% shaded. Rest areas should be located along primary sidewalks/walkways. Ensure appropriate lighting along the street. All paths should be suitably illuminated adopting pedestrian-scale lighting. Adhere to the principles of universal design. Refer to Part 2 – Section 208 for further details. 105.06.02 Sidewalks and Walkways The design of sidewalks and walkways varies depending on the setting, standards and requirements of local agencies. Further pedestrian facilities advice is given in the Abu Dhabi USDM. Traffic volume/pedestrian warrants for sidewalks or other types of walkways along highways have not been established. In general, whenever the roadside and land development conditions are such that pedestrians regularly move along a highway, those pedestrians should be furnished with a sidewalk or other walkway, as is suitable to the conditions. Sidewalks are typically within the public right-of-way and pedestrian facilities should be provided on the relevant roadways. (1) Replacement in Kind - Where existing sidewalks are to be disturbed by highway construction, the replacement applies only to the frontages except: (a) as part of a right-of-way agreement. (b) where the safety or capacity of the highway will be improved. (2) Conventional Highways - The roadway cross section usually provides areas for pedestrians. (3) Primary Roads and other Controlled Access Facilities - Sidewalks should be built across the primary road right-of-way on overpasses and through underpasses where necessary to connect with existing or planned sidewalks. (4) Overpass and Underpass Approaches - Where sidewalks are planned on overpass structures or under a structure, an area should be provided to accommodate future sidewalks. (5) School Pedestrian Walkways - School pedestrian walkways may be identified along a route used by school pedestrians that is not limited to crossing locations, but includes where Version 2.0 Part 2 – Section 100 Page 14 of 20 November 2014 Access should also be provided at bridge sidewalk approaches and at kerbs in the vicinity of pedestrian separation structures. (9) Vehicular Tunnels . Occasionally these departures are justified. Version 2. (8) Transit Stops – Sidewalks/walkways should be built to connect transit stops to local streets. Where a pedestrian grade separation is justified. a kerb ramp must be constructed.07 PEDESTRIAN GRADE SEPARATIONS Pedestrian grade separation takes the form of pedestrian overpasses or underpasses. 105. suburban roadways. Where a need is identified at an existing kerb on a conventional roadway. prior to planning acceptance. which provides more opportunities for vandalism and criminal activity.ADM is responsible for maintaining and replacing damaged sidewalks and walkways within the right-of-way.ROADWAY DESIGN MANUAL physical conditions require students to walk in. with reference to the “School Safety Project”. 105. (10) Maintenance . railways. (6) Frontage Roads . but it is important that each Departure from Standard is documented and approved in writing. Pedestrian patterns need to be determined. or along.08 GUIDELINES FOR THE LOCATION AND DESIGN OF KERB RAMPS Adequate and reasonable access for the safe and convenient movement of persons with disabilities is to be provided across kerbs that are constructed or replaced at pedestrian crosswalks. 106 DEPARTURES FROM STANDARDS A Departure from Standards relates to a design feature which does not meet the design standards presented in this Roadway Design Manual.Sidewalks may be built on separated cross streets where reconstruction of the cross street is made necessary by the primary road project and where the criteria of paragraph (3) above apply. These crossings are used for the traversing of primary roads. Underpasses tend to provide less visibility. (7) Separated Cross Streets .Sidewalks may be built along frontage roads connecting local streets that would otherwise dead end at the primary roads.0 Part 2 – Section 100 Page 15 of 20 November 2014 . Further information may be obtained from ADM. an overpass is preferred. light rail transit and any other physical obstacle.Sidewalks and pedestrian facilities may be built as part of vehicular tunnels which do not require ventilation as part of the tunnel structure. 2.  Incremental improvements. This may include the widths of lanes. Proposed Departure from Standards A. reconstruction. design speed.  Existing roadway description. cross slope. The request sheet shall include the following information:  Proposed project. Proposed Project Cost . B. roadway widening. Project Description – Brief description of the project. rehabilitation. If relevant. utility relocation.  Proposed Departure from Standards. shoulders. etc.0 Part 2 – Section 100 Page 16 of 20 November 2014 .  Additional cost required to comply with Standards. environmental mitigation. grades. structures. noting any existing non-standard features. This request sheet shall be presented to ADM and other relevant stakeholders for written approval. The geographical project limits and length will be provided. Describe the proposed Departure from Standards or the existing departure which is Version 2. This will include the type of project and/or major elements of work to be done. provide a similar brief description of adjacent existing roadway segments. superelevation. horizontal and vertical alignment and clearances. such as safety or operational improvement.ROADWAY DESIGN MANUAL The request for approval of these departures shall be in the form of a Departure from Standards Request. Existing Roadway Description Describe the existing roadway features relevant to the proposed Departure from Standards. etc. median. including roadway. sight distance. B. DEPARTURE FROM STANDARDS REQUEST 1. Proposed Project A. etc. State the specific design standard(s) which are not being met and refer to the relevant RDM section/clause number. clear zones and structures. 3. A detailed description of the items required in the Departure from Standards Request is included on the following pages. right-of-way.  Supportive data.Include an estimate of the proposed project cost segregated into the major elements. quoted for the proposed future design year. plus an evaluation of the effect of the requested departure on accident types and frequencies. drainage. Accident Analysis . If relevant.0 1. meeting minutes. Reasons for granting departures include a combination of excessive cost. guardrail upgrade. include an accident data analysis to identify prevalent accident types and causes. local opposition and consistency with adjacent roadway segments. 3. Additional Cost Required to Comply with Standards Provide a realistic estimate of the additional cost required to meet the design standard for which the proposed departure is requested. Provide enough information on costs versus benefits. street lighting.. For a proposed departure. 6. etc. Provide plan sheets. Traffic Data . eliminating roadside obstructions. state whether it is an improvement over the existing condition. Describe proposed improvements that would qualify as safety enhancements over the existing condition.Safety is of primary importance when considering design approval for Departures from Standards. Part 2 – Section 100 Page 17 of 20 November 2014 . These alternatives should normally be investigated prior to requesting a departure. standard solution. C. such as median barrier. Attachments - Version 2. profiles and/or special details to clearly illustrate the proposed departure. right-of-way and environmental impacts. 2. right-of-way impacts and/or environmental impacts. 4. resolutions. C. 5. B.ROADWAY DESIGN MANUAL proposed to be maintained. etc. Incremental Improvements Discuss other practical alternatives that are intermediate in scope and cost between the proposed project (requiring this Departure from Standards) and the full. studies. etc. Provide a location plan for the project. correcting superelevation. which further develop or clarify the proposed departure. Provide a thorough brief justification for the departure. Attach pertinent letters.Provide both ADT and DHV (design hourly volumes) traffic information. cross sections. to explain why none of the incremental alternatives are recommended. Supportive Data A. signage.. Supportive factors have included low accident frequency. flattening slopes. All city. and shoulders provide cyclists an opportunity to pull over to let faster traffic pass. Measures such as the following. except those highway segments where bicycle travel is prohibited. to ensure connectivity and network development. regional and other local agencies responsible for cycleways or roads. they need access to all destinations. most agencies do not allow bicycles on full-access controlled facilities. also greater sensitivity to out of direction travel and steep uphill grades. which are generally low cost. shall equal or exceed the minimum bicycle design criteria contained in this manual. if no shoulder is present.01 GENERAL Provision for bicycles has become an important factor requiring consideration in the highway design process. most of the mileage needed for bicycle travel is provided by the street and highway system. etc. cyclists generally have the same rights and duties that motor vehicle drivers do when using the highway system. designing for bicycle traffic and motor vehicle traffic are similar.  Wide outside traffic lane (4. While many highway agencies allow bicycles on partial-access controlled facilities. All transportation improvements are an opportunity to improve safety.ROADWAY DESIGN MANUAL 107 ROAD SAFETY AUDITS Road Safety Audits are to be undertaken in accordance with the procedures set out in the ADM “Emirate of Abu Dhabi Road Safety Audit Manual”. clean riding surface. The main differences between bicycle and motor vehicle operations are lower speed and acceleration capabilities. In Abu Dhabi. they need adequate sight distance. For example. Therefore.  Adjusting manhole covers to grade. since cyclists are required to ride as far to the right as possible. bicycle travel can be enhanced by cycleways or improvements to the right-hand portion of roadways.2m minimum). they make the same merging and turning movements. Guidance that addresses safety and mobility needs of cyclists is distributed throughout this manual and other stakeholder’s literature. Generally speaking. can considerably enhance safety and capacity for bicycle traffic on roadways:  Paved shoulders. access and mobility for the bicycle mode of travel. Fortunately. The decision to develop cycleways should be made in consultation and coordination with local stakeholders responsible for cycleway planning.  Maintaining a smooth. 108 BICYCLE FACILITIES 108.  Bicycle-safe drainage grates. Version 2. When feasible.0 Part 2 – Section 100 Page 18 of 20 November 2014 . a wider shoulder than the minimum standard should be considered. where bicycles are required to travel or independently constructed cycle routes separate to the roads.  Expansion joints. it is appropriate to supplement further the existing highway system by providing specifically designated cycleways (for exclusive or non-exclusive bicycle use).  Multiple-lane entrance/exit ramps. access lanes and sidewalks due to right-of-way constraints. Cycle tracks may be a shared lane with frontage lanes. Shared pedestrian and cycle track layouts are discussed in Part 2 – Section 208.  Utility access covers on shoulders. parks and housing developments are usually located to be readily accessible by car.0 Part 2 – Section 100 Page 19 of 20 November 2014 . Arterials are often the only direct connection between areas of population and locations to which the public wishes to travel. Schools. cyclists or non-motorised users. the designer should consider the effects on the safety and operation of the arterial. including but not limited to:  Shoulder widths.  Sight distance at entrance/exit ramps. 108.02 SPECIAL BICYCLE FACILITIES At certain locations or in certain corridors.  Frequency and spacing of entrance/exit ramps.  Drainage grates. However.  Longitudinal/transverse edges and joints.  Arterial to arterial interchanges. for primary walking. cycling routes and design standards. streets. Version 2. it is necessary to evaluate the road features for their compatibility with safe travel.  The presence and design of rumble strips. pedestrians and bicycle riders may also wish to travel to the same destination points. Reference should also be made to the latest version of the “Abu Dhabi Walking and Cycling Master Plan (WCMP)” produced by the DoT.  Traffic volumes on entrance/exit ramps and on lanes merging into exit ramps.ROADWAY DESIGN MANUAL For further information and guidelines on provision for bicycles. refer to the latest edition of AASHTO “Guide for Development of Bicycle Facilities”. A special effort should be made to provide the greatest degree of safety within the economic constraints that must always be considered. When such a situation exists. When a new road segment is to remain open or an existing road segment is to be reopened to pedestrians.  AASHTO Roadside Design Guide. This may mean special sight distance considerations. provisions for left turn bicycle movements.Section 2 Part 6 – TD42/95 Geometric Design of Major/Minor Priority Junctions. Roundabouts: An Informational Guide. special lane markings to channelize and separate bicycles from right turning vehicles.0 Part 2 – Section 100 Page 20 of 20 November 2014 . so that consideration of bicycles is an essential element in the design of the highway itself. wider roadways to accommodate on-street lanes. Transportation Research Board 2010.  Transportation Research Board (TRB): Highway Capacity Manual 2010  AASHTO MASH (Manual for Assessing Safety Hardware).04 BICYCLES AT INTERSECTIONS When on-street bicycle lanes and/or off-street bicycle paths enter an intersection. grades and sight distance. or special traffic signal designs (such as conveniently located push buttons at actuated signals or even separate signal indication for cyclists). operating characteristics and requirements. Version 2. GUIDELINES AND REFERENCES The Consultant shall comply with the latest versions (latest edition with interim revisions) of the following documents.Section 2. design features of separate bike facilities are controlled by the adjoining roadway. 109 ADDITIONAL STANDARDS. 2011.  Highways Agency. 2011.03 BICYCLE CHARACTERISTICS To provide for bicycle traffic. 2011.  AASHTO Guide for Development of Bicycle Facilities. UK: Design Manual for Road and Bridgeworks .  NCHRP Report 672. 2011.  Highways Agency. These factors determine acceptable turning radii.ROADWAY DESIGN MANUAL 108. the design of the intersection should be modified accordingly. it is necessary to become familiar with bicycle dimensions. In many instances. UK: Design Manual for Road and Bridgeworks . Part 3 – TD16/07 Geometric Design of Roundabouts. Second Edition. 2012. which is not considered to be exhaustive:  AASHTO “A Policy on Geometric Design of Highways and Streets”. (commonly referred to as the “Green Book”)  Caltrans Highway Design Manual. 108. 0 Part 0 – Divider November 2014 .ROADWAY DESIGN MANUAL SECTION 200 : GEOMETRIC DESIGN STANDARDS Version 2. especially those routes with high volumes of trucks or recreational vehicles.25m. including motorists and cyclists. which represents the portion of the vehicle that needs to be visible for a driver to recognize that the object ahead is another vehicle. passing. whose eyes are 1. at interchanges and intersections. Passing on sag vertical curves can be accomplished both day and night because headlights can be seen through the entire curve.33m. including private road connections.01 GENERAL Sight distance is the continuous length of roadway ahead visible to the driver. Passing must be accomplished without reducing the speed of an oncoming vehicle travelling at the design speed. Passing sight distance is used where use of an opposing lane can provide passing opportunities. At critical locations. passing sight distance is provided at locations where combinations of alignment and profile do not require the use of crest vertical curves. stopping and decision. 201. less an allowance of 0. Generally. In general. Passing should be carried out on tangent horizontal alignments (straights) with constant grades or a slight sag vertical curve.02 PASSING SIGHT DISTANCE Passing sight distance is the minimum sight distance required by a driver to safely pass another vehicle. Version 2.01 lists sight distance standards. Economics should be weighed against providing passing sight distance or auxiliary passing lanes. Passing sight distance for crest vertical curves is 7 to 17 times longer than the stopping sight distance. Three types of sight distance are considered herein. The sight distance available for passing is the longest distance at which a driver of a passenger vehicle.GEOMETRIC DESIGN STANDARDS 201 SIGHT DISTANCE 201.08m on the road ahead. Stopping sight distance is the minimum sight distance for a given design speed to be provided on multi-lane highways and on 2lane roads when passing sight distance is not economically obtainable. Table 200. a stretch of 3-lane or 4-lane passing section with stopping sight distance is sometimes more economical than two lanes with passing sight distance. The object height is based on a vehicle height of 1. minimum passing sight distance should be provided for 60% of the route length in level terrain.0 Part 2 – Section 200 Page 1 of 32 November 2014 . but it is impracticable to design crest vertical curves to provide for passing sight distance because of the high cost where crest cuts are involved. Stopping sight distance is also is to be provided for all users. can see an object vehicle of height 1. 2lane highways should provide for passing where possible. 40-60% in rolling terrain and 20-60% in mountainous terrain.08m above the pavement.ROADWAY DESIGN MANUAL SECTION 200 . Drivers are reluctant to pass on a long crest vertical curve. Decision sight distance is used at major decision points. Passing sight distance is only considered on 2-lane roads and should be provided at frequent intervals. Ordinarily. at-grade intersections and private road connections.01 shows the standards for stopping and passing sight distances. related to design speed. Stopping sight distance is measured from the driver’s eyes. to a 0. Stopping sight distance is the minimum provided for interchanges.01 SIGHT DISTANCE STANDARDS Stopping Sight Distance (m) Design Speed (kph) Downgrades Level Minimum Passing Sight Distance (m) Upgrades 0% 3% 6% 9% 3% 6% 9% 30 35 32 35 35 31 30 29 120 40 50 50 50 53 45 44 43 140 50 65 66 70 74 61 59 58 160 60 85 87 92 97 80 77 75 180 70 105 110 116 124 100 97 93 210 80 130 136 144 154 123 118 114 245 90 160 164 174 187 148 141 136 280 100 185 194 207 223 174 167 160 320 110 220 227 243 262 203 194 186 355 120 250 263 281 304 234 223 214 395 130 285 302 323 350 267 254 243 440 Source : AASHTO “A Policy on Geometric Design of Highways and Streets”.ROADWAY DESIGN MANUAL 201.03 STOPPING SIGHT DISTANCE Stopping sight distance is the distance required by a driver. stopping sight distance is the minimum sight distance provided on multi-lane and 2-lane roads. to stop after sighting an object on the road. If providing passing sight distance is not economically feasible. Version 2. travelling at a given speed. 1. Table 200. 2011. Table 200. 2011 contains a thorough discussion of the derivation of stopping sight distance.08m above the road.0 Part 2 – Section 200 Page 2 of 32 November 2014 .6m high object on the road ahead. Chapter 3 of AASHTO “A Policy on Geometric Design of Highways and Streets”. buildings.6m high. roadside rest areas.02 (derived from AASHTO “A Policy on Geometric Design of Highways and Streets”. Widening is an economic tradeoff that must be evaluated along with other options. Crest vertical curves can cause additional reductions in sight distance. sight distance greater than stopping sight distance is desirable to allow drivers more time for making decisions. off-ramp noses to interchanges. Decision sight distance is based on a 1.05 DECISION SIGHT DISTANCE Decision sight distance is the distance required for a driver to detect an unexpected or difficult to perceive source of potential hazard in a roadway environment that may be visually cluttered. walls. Technical reductions in design speed are also caused by partial or momentary horizontal sight distance restrictions and glare screens. The clear distance is measured from the centre of the inside lane to the obstruction. The sight distance is a chord of the curve and the stopping sight distance is measured along the centreline of the inside lane around the curve. select an appropriate speed and path. and initiate and complete the required manoeuvre safely and efficiently. longitudinal barriers or trees).6m object height. 2011) provide appropriate decision sight distances rounded for design purposes.0 Part 2 – Section 200 Page 3 of 32 November 2014 . branch connections. The line of sight is assumed to intercept the view obstruction at the midpoint of the sight line. Version 2.08m above the centre of the inside lane (inside with respect to the curve) and the object is 0.08m eye height and a 0.04 STOPPING SIGHT DISTANCE ON HORIZONTAL CURVES Where an object adjacent to the roadway restricts sight distance (e. the minimum radius of curvature is determined by the stopping sight distance. The driver's eye is assumed to be at a height 1. 201. The decision sight distances in Table 200.g. Decision sight distance is used at major decision points such as lane drops. changes in cross section. At these locations. Cuts may be widened where vegetation restricting horizontal sight distance is expected to grow on finished slopes. vista points and inspection stations.ROADWAY DESIGN MANUAL 201. centrifugal force is resisted by the vehicle weight component parallel to the superelevated surface and the tyre side friction. However. it does not generally apply to streets having lower design and posted speeds.1 s to 12. Superelevation is the sloping of the roadway surface upwards towards the outside of the curve.0 Part 2 – Section 200 Page 4 of 32 November 2014 . However.0 s to 14. the vehicle is held on its curved path by side friction between the tyres and pavement.02 DECISION SIGHT DISTANCE Decision Sight Distance for Avoidance Manoeuvre (m) Design Speed (kph) A Stop on Urban Road B Speed/Path/Direction Change on Suburban Road C Speed/Path/Direction Change on Urban Road 50 155 170 195 60 195 205 235 70 235 235 275 80 280 270 315 90 325 315 360 100 370 355 400 110 420 380 430 120 470 415 470 130 525 450 510 Note: Values of t (pre-manoeuvre time in seconds) A : t = 3. As a vehicle travels a curved section of road. On a superelevated roadway. If the vehicle is not skidding. because for a given curve radius a certain superelevation rate is exactly correct at only one speed. such as access lanes in urban areas.01 GENERAL Superelevation applies to roads with higher operating speeds (such as freeways and expressways). 202 SUPERELEVATION 202.0 s B : t varies from 12. it is subjected to centrifugal force which tends to push it towards the outside of the curve. it is impractical to balance centrifugal force by superelevation alone.ROADWAY DESIGN MANUAL Table 200.9 s C : t varies from 14. side thrust will either be towards or away from the curve centre. Roadways are superelevated to further counter centrifugal force. all forces are in equilibrium and are governed by the following equation: Version 2. At all other speeds. This thrust must be offset by side friction. If the surface is flat. 2011.5 s Source : AASHTO “A Policy on Geometric Design of Highways and Streets”. 202.610 0.04 Curve Radius (m) e Curve Radius (m) e <180 0.150m (60-100kph) and R=1.03 MAXIMUM SUPERELEVATION RATES Design Speed (60kph .04 460 .05 - - 300 .ROADWAY DESIGN MANUAL Centrifugal Factor = e + f = 0.04 < 150 0. Table 200.460 0. 2. Version 2.06 - - 180 .0 Part 2 – Section 200 Page 5 of 32 November 2014 .0079V2 = V2 R 127R where: e emax f R V = = = = = Superelevation rate in m per m Maximum superelevation rate for a given condition Side friction factor Curve radius in m Velocity in kph This equation is used to design superelevated curves for comfortable operation.02 SUPERELEVATION STANDARDS Maximum superelevation rates for various roadway classifications are shown in Table 200.150 See note below > 1.500 0.03 610 – 2.300 0.100kph) Expressway / Boulevard / Avenue max for e =0.300 0.05 show values for design elements related to speed and horizontal curvature.1. Curves in excess of R=2.02 > 2.04 and 200. Streets and access lanes (including frontage lanes) do not require superelevation and can be crowned.500 See note below Notes: 1.03.03 150 .02 300 . Standard superelevation rates are designed to hold the portion of the centrifugal force that must be taken up by tyre friction within allowable limits.06 Design Speed (60kph and below) City Boulevard / Avenue max for e =0.150 0.500m (<60kph) require no superelevation and can be designed with normal crowns. Tables 200. 4 51 132 273 435 626 865 1110 1390 1730 2.0 24 64 137 236 356 516 690 893 1150 3.2 20 54 114 199 303 443 597 779 1010 3.6 38 99 209 345 508 720 944 1200 1510 2.6 14 38 81 144 222 329 448 591 767 3.04 MINIMUM RADII FOR DESIGN SUPERELEVATION RATE. 2011) Version 2.4 17 45 96 170 260 382 518 680 879 3.ROADWAY DESIGN MANUAL Table 200.2 75 187 363 534 749 1020 1290 1590 1980 2. DESIGN SPEEDS AND E MAX = 4% Vd= 20 kph Vd= 30 kph Vd= 40 kph Vd= 50 kph Vd= 60 kph Vd= 70 kph Vd= 80 kph Vd= 90 kph Vd= 100 kph R (m) R (m) R (m) R (m) R (m) R (m) R (m) R (m) R (m) NC 163 371 679 951 1310 1740 2170 2640 3250 RC 102 237 441 632 877 1180 1490 1830 2260 2.0 Part 2 – Section 200 Page 6 of 32 November 2014 .0 8 22 47 86 135 203 280 375 492 e (%) where: max e R Vd e NC RC = = = = = = 4% Radius of Curve Assumed Design Speed Rate of Superelevation Normal Crown Section Remove Adverse Camber vs Normal Camber (from AASHTO “A Policy on Geometric Design of Highways and Streets”.8 12 31 67 121 187 278 381 505 658 4.8 30 79 167 283 422 605 802 1030 1320 3. 2 17 40 79 142 214 315 421 549 701 871 1120 1330 5.4 27 63 121 210 311 446 584 746 938 1140 1410 1630 4.ROADWAY DESIGN MANUAL Table 200.0 78 170 300 443 615 831 1050 1290 1590 1870 2240 2510 3.0 8 21 43 79 123 184 252 336 437 560 756 951 e (%) where: max e R Vd e NC RC = = = = = = Vd= 60 kph MAX 6% Radius of Curve Assumed Design Speed Rate of Superelevation Normal Crown Section Remove Adverse Camber vs Normal Camber (from AASHTO “A Policy on Geometric Design of Highways and Streets”.2 70 152 269 402 561 761 959 1190 1470 1730 2080 2330 3.6 97 212 372 540 746 1000 1260 1540 1890 2210 2630 2930 2. DESIGN SPEEDS AND E Vd= 20 kph Vd= 30 kph Vd= 40 Vd= 50 kph kph R (m) R (m) R (m) R (m) NC 194 421 738 RC 138 299 2.4 61 133 239 364 511 697 882 1100 1360 1600 1940 2180 3.6 51 113 206 329 465 640 813 1020 1260 1490 1810 2050 3.0 36 82 155 261 380 535 690 870 1090 1300 1590 1820 4.6 24 56 108 190 283 408 538 692 873 1070 1330 1540 4.2 122 2.4 = 6% Vd= 70 kph Vd= 80 Vd= 90 kph kph Vd=100 kph Vd=110 kph Vd=120 kph Vd=130 kph R (m) R (m) R (m) R (m) R (m) R (m) R (m) R (m) 1050 1440 1910 2360 2880 3510 4060 4770 5240 525 750 1030 1380 1710 2090 2560 2970 3510 3880 265 465 668 919 1230 1530 1880 2300 2670 3160 3500 109 236 415 599 825 1110 1380 1700 2080 2420 2870 3190 2.8 87 190 334 488 676 910 1150 1410 1730 2020 2420 2700 3.8 42 96 177 294 422 586 749 939 1170 1390 1700 1930 4.8 11 28 56 102 156 232 315 416 537 679 900 1110 6.8 21 50 97 172 258 374 496 641 812 997 1260 1470 5.05 MINIMUM RADII FOR DESIGN SUPERELEVATION RATE.6 13 32 63 115 176 260 351 463 594 747 980 1190 5.4 15 36 71 128 195 287 386 506 648 810 1060 1260 5. 2011) Version 2.2 31 72 136 234 343 488 635 806 1010 1220 1500 1720 4.0 19 45 88 156 235 343 457 594 755 933 1190 1400 5.0 Part 2 – Section 200 Page 7 of 32 November 2014 . should be shifted to the centreline. and driver perception should be considered when selecting the axis of rotation. the axis of rotation. Where the initial median width is greater than 20m and the ultimate median width is 20m or less.04 SUPERELEVATION TRANSITION General . or improve curve perception for curves preceded by long relatively level tangents.Superelevation transitions should be designed in accordance with Figures 200.The axis of rotation shall be at the median edge of each travelled way. superelevation transitions.03 AXIS OF ROTATION Aesthetics.02 and 200. except where the resulting initial median slope would be steeper than 10:1.The axis of rotation should be considered on an individual project basis and the most appropriate case for the conditions should be selected. 202. grade distortion. Appearance and drainage considerations shall be considered when selecting the axis of rotation. Primary Roadway Connections and Ramps . for bridges with decked medians. The transition length should be based upon the combination of superelevation rate and width of rotation plane. the axis of rotation shall be at the centreline. Aesthetics.The axis of rotation shall be at the roadway centreline. if not already on centreline. Version 2. Divided Roadways .The axis of rotation may be about either edge of travelled way. the axis of rotation should be at the ultimate median edges of travelled way.01. drainage. Where the ultimate median width is greater than 20m. and driver perception should be considered when selecting the axis of rotation.03.ROADWAY DESIGN MANUAL 202. in special cases changing the axis of rotation to the inside travelled way edge can avoid drainage problems caused by superelevation. superelevation transitions. drainage. (a) Primary Roadways . the axis of rotation should be at the centreline. Edge of travelled way and shoulder profiles should be plotted and irregularities resulting from interactions between the superelevation transition and vertical alignment of the roadway should be eliminated by introducing smooth curves. the axis of rotation should be at the centreline. Edge of travelled way and shoulder profiles will also reveal flat areas which are undesirable from a drainage standpoint and must be avoided. In the latter case. Undivided Roadways . However. or centreline if multi-lane. (b) Conventional Highways .0 Part 2 – Section 200 Page 8 of 32 November 2014 . the axis of rotation should normally be at the ultimate median edges of travelled way. 200.Where the initial median width is 20m or less. To avoid saw tooth on bridges with decked medians. grade distortion. However. ROADWAY DESIGN MANUAL Figure 200.0 Part 2 – Section 200 Page 9 of 32 November 2014 .01 Elements of a Superelevation Transition – Isometric View Version 2. 02 Superelevation Transitions Version 2.0 Part 2 – Section 200 Page 10 of 32 November 2014 .ROADWAY DESIGN MANUAL Figure 200. 0 Part 2 – Section 200 Page 11 of 32 November 2014 .03 Superelevation Transitions for Compound Curve Version 2.ROADWAY DESIGN MANUAL Figure 200. An example of expressway superelevation development is shown on Figures 200. Shoulder Transitions . The remaining transition length will be on the tangent.0 Part 2 – Section 200 Page 12 of 32 November 2014 .Roadways separated by barrier or median will be superelevated at independent rates. 200. the transition will begin/end at the start of the curve determined by the inside roadway transition. When superelevation becomes greater than -3. The transition location will be adjusted to begin/end at a 10m chainage station. For roadways on the inside of the curve. Version 2.02 and 200.0 percent. the criteria in Section 202.04 and 200.ROADWAY DESIGN MANUAL Superelevation Transitions . the highest possible superelevation rate and transition length shall be used. Restrictive Areas . Where feasible.03. The minimum transition length for a two-lane roadway is shown on Tables 200.03. The transition length will be based on pavement width and superelevation change. The profile of the outside edge of through pavement cannot differ from the profile gradeline by more than the percentage shown on Tables 200.05 SUPERELEVATION OF COMPOUND CURVES Compound curve superelevation shall be per Figure 200. the pavement and shoulder will rotate in unison. where full superelevation cannot be achieved.04 shall apply.04 and 200. Superelevation Transitions on Bridges – Superelevation transitions on bridges should be avoided. The location of a superelevation transition. Shoulder superelevation transitions should be smooth and compatible with the transition of the adjacent pavements. and will be an unbroken line throughout the transition. For roadways on the outside of the curve.05.The shoulder plane rotates about the adjacent edge of travelled way as well as the rotational axis of the travelled way. An additional transition length is required to rotate the outside shoulder from -3.0 percent (normal shoulder slope). with respect to the point of curvature. This shoulder transition length must be added to the pavement transition length to get the total transition length.05.0 percent (normal shoulder slope) to -1. But. 202. will be determined using the inside roadway transition.5 percent (normal pavement slope). in no case shall the cross slope rate of change exceed 4% per 20m. Approximately one-third of the transition length will be placed on the curve. the outside shoulder will begin rotating when the inside roadway pavement has reached a superelevation of -3.01. For multiple lane roadways the minimum length shall increase proportionately.In restrictive areas. 01 GENERAL Horizontal alignment consists of a series of circular curves and tangent sections.Every effort should be made to exceed minimum values. Table 200. Introduction of curves with lower design speeds shall be avoided at the end of long tangents. for further guidance on alignment consistency. topography.0 Part 2 – Section 200 Page 13 of 32 November 2014 . and such minimum radii should only be used when the cost or other adverse effects of realizing a higher standard are inconsistent with the benefits. profile. The major factors influencing horizontal alignment design are safety.ROADWAY DESIGN MANUAL 203 HORIZONTAL ALIGNMENT 203. aesthetics and functionality. All of these factors must be balanced to produce the safest. and at the same time adequate for the design classification of the roadway. If a glare screen or median barrier is used.03 displays the maximum comfortable speed for various curve radii and superelevation rates. Above a 6.000m radius. design speed. the minimum curve length should be 240m to avoid a kinked appearance. cost. The horizontal alignment should provide safe continuous uniform operation for substantial roadway lengths. In design. and not more than 15 kph less than the measured or estimated running (85th percentile) speed of vehicles on the approach roadway. or at other locations where high approach speeds may be anticipated. The following standards apply to horizontal curvature on both 2-lane and multi-lane roadways.For central angles less than 10 degrees.Sudden reductions in alignment standards shall be avoided. In no case shall the design speed between successive curves change by more than 15 kph. type of facility.02 STANDARDS FOR HORIZONTAL CURVATURE Minimum Curvature . In no case shall sight distance or other safety considerations be sacrificed to meet the above requirements. On roadways in mountainous or rolling terrain where horizontal and vertical curves are superimposed at grade summit or sag. For central angles smaller than 30 minutes. As an aid to designers. most economical alignment. The horizontal alignment shall provide at least the minimum stopping sight distance for the chosen design speed at all points along the roadway. adjustments may be necessary to maintain the required sight distance on divided roadway curves. Curve Length and Central Angle . no curve is required. geotechnical constraints. Version 2. the design speed of the horizontal curve should at least be equal to that of the crest or sag. parabolic curves may be used. See “Combination of Horizontal and Vertical Alignment” in Chapter III of AASHTO. “A Policy on Geometric Design of Highways and Streets”. safety is always a major factor. except as noted. steep downgrades. Alignment Consistency . 203. which is in harmony with the natural contours of the land. spirals transitions should conform to the Clothoid definition. The length of spiral should be the same as the Superelevation Runoff Length shown previously. intersections should be on tangent sections or flat horizontal curves with very little superelevation. For a general discussion of spiral transitions. except where use of a simple curve results in excessive cost. In the typical design. alignment and safety considerations shall govern. The total arc length of a compound curve should not be less than 150m. with crown runoff being handled as per the previous notes. horizontal alignment. Broken Back Curves . If compound curves are used. the larger radius should follow the smaller radius. Broken back curves are unsightly. It is used to establish elevations for all roadway features. roadway class. When used.If possible. a bridge should be located entirely on a tangent or curve because superelevation transitions on bridges almost always result in unsightly bridge and bridge railing appearance.ROADWAY DESIGN MANUAL Lane curve lengths in excess of 800m on 2-lane roadways should be avoided in consideration of the safety aspects associated with driver attentiveness and oncoming headlight glare. the shorter radius should be at least two-thirds the longer radius.Compound curves shall be avoided.0 Part 2 – Section 200 Page 14 of 32 November 2014 . cultural development. see AASHTO “A Policy on the Geometric Design of Highways and Streets”. Intersections and Interchanges . Alignment at Bridges . sight distance. safety. 204 VERTICAL ALIGNMENT 204.If possible.02. undesirable and should be avoided.Used to transition from a tangent alignment to a circular curve and between circular curves of unequal radius. the connecting tangents shall be long enough to accommodate the standard superelevation runoffs given on Figure 200. In no case shall the cross slope rate of change exceed 4% per 20m. such as a typical diamond interchange. Interchanges.A broken back curve consists of two curves in the same direction joined by a short tangent section. A tangent alignment should be maintained between intersections for signal visibility and lane assignment determinations required by the motorist. Reverse Curves . when the shorter radius is 300m or less.30m and design speed is greater than 65 kph or the superelevation rate exceeds 4%.01 GENERAL Vertical alignment consists of a series of grades connected by parabolic vertical curves. and Version 2. drainage. It is controlled mainly by topography. Compound Curves .When horizontal curves reverse direction. On one-way roads. include two closely spaced at-grade intersections that function inter-dependently. Spiral Transitions . Their use is recommended whenever the vehicular lane width is less than 3. costs. full superelevation occurs where the spiral curve meets the circular curve. However. some undulation in the grade line is often advantageous for construction economy. 204. flatter minimum grades may be warranted in Version 2.The grade line may be positioned at either the median centreline or at the ultimate median edge of travelled way. the elevation of the grade line is often controlled by drainage considerations. or centreline if multi-lane.03 STANDARDS FOR GRADES Maximum Grades . economic comparisons involving earthwork quantities and/or retaining walls should be made. based on roadway type. 3. Divided Roadways . it is desirable to provide the flattest grades practicable. 2. In flat terrain.ROADWAY DESIGN MANUAL aesthetics. The vertical alignment should be selected taking into consideration final appearance of the roadway.3 percent for kerbed pavement sections and 0. In rolling terrain. economic comparisons should include vehicle operating costs. The median width is non-uniform. All portions of the vertical alignment shall meet minimum sight distance requirements. the grade line is usually more closely dependent upon physical controls. a grade line on a tangent alignment exhibiting a series of humps visible for some distance ahead should be avoided whenever possible. The former case is appropriate for paved medians 9m wide or less.06 lists the maximum grades for design of urban roadways. When long or steep grades are involved. The median edges of travelled way of the two roadways are at equal elevation. 204. Minimum Grades . however. For example.0 Part 2 – Section 200 Page 15 of 32 November 2014 .The desirable minimum grades should not be less than 0. Primary Roadway Connections and Ramps .The grade line may be positioned at either edge of the travelled way.02 VERTICAL ALIGNMENT POSITION WITH RESPECT TO CROSS SECTION The grade line (defined by the master string) should generally coincide with the axis of rotation for superelevation and should relate to the cross section as follows: Undivided Roadways . Steep grades affect truck speeds and overall capacity. Steep grades affect truck speeds and overall capacity and they also cause operational problems at intersections. For these reasons.Table 200.The grade line should coincide with the roadway centreline. In rolling hills or mountainous terrain. The roadways are at different elevations. The latter case is appropriate when: 1. A balanced earthwork design is most cost effective. Minimum grades can be maintained in very flat terrain by use of a rolling profile. In developed urban areas with extremely flat terrain. In considering alternative profiles.2 percent in very flat terrain. A profile with such curvature should normally be avoided. Adjusting the edge grade or shortening the vertical curve may be required. Version 2. Grade (%) Boulevard / Avenue 2 3 Street 2 3 Access Lane 2 3 Urban Road Type 204.04 VERTICAL CURVES Parabolic vertical curves used in roadway design are indicated in Figure 200. particularly in sags where the view of both curves is not pleasing. To recognize the distinction in design speed and to approximate the range of current practice. in kilometres per hour. Flat vertical curves may develop poor drainage in the level section.6 times the design speed.04. Table 200. minimum lengths of vertical curves are expressed as 0. Broken-back vertical curves consist of two vertical curves in the same direction separated by a short grade tangent. It may be more economical to construct passing lanes than to obtain passing sight distance by using a long vertical curve.ROADWAY DESIGN MANUAL consideration of adjacent building elevations and offsite drainage problems associated with rolling profiles. Figures 200. Design of long vertical curves should be avoided because many drivers will not pass on curves over 1 km long.0 Part 2 – Section 200 Page 16 of 32 November 2014 . The use of minimum grades flatter than those specified above will require case by case approval by ADM. Grade (%) Absolute Max. despite adequate sight distance.06 GRADE STANDARDS Desirable Max.06 are used to obtain vertical curve lengths for both sags and crests.05 and 200. ROADWAY DESIGN MANUAL Figure 200.0 Part 2 – Section 200 Page 17 of 32 November 2014 .04 Symmetric Parabolic Vertical Curve Version 2. Upper Range. “A Policy on Geometric Design of Highways and Streets”.ROADWAY DESIGN MANUAL Figure 200.0 Part 2 – Section 200 Page 18 of 32 November 2014 . “A Policy on Geometric Design of Highways and Streets”.Upper Range.06 Design Controls for Sag Vertical Curves .05 Design Controls for Crest Vertical Curves. 2011 Version 2. for Stopping Sight Distance . from AASHTO. 2011 Figure 200. from AASHTO. ROADWAY DESIGN MANUAL 204.07 shows the speed reduction (kph) for an assumed typical heavy truck of 180 kg/kW as a function of grade length and percentage upgrade. and contributes to heavy truck delays. Consideration should be given to adding lanes where the truck speed reduction is greater than 15 kph and there is a significant reduction in the Level of Service when moving from the approach segment to the grade. in addition to the above criteria. Figure 200. the upgrade traffic flow is in excess of 200 vehicles per hour and the truck factor is in excess of 10%. On two-lane roadways. Assumed Typical Heavy Truck of 180 kg/kW Entering Speed 90 kph from AASHTO. Figure 200. Generally. capacity. “A Policy on Geometric Design of Highways and Streets”.07 Critical Lengths of Grade for Design. a truck speed reduction of up to 15 kph does not significantly impact on roadway capacity. Decision sight distance should be provided at climbing lane drops on primary roads. level of service. The uphill grade length must be considered because it has a major effect on operational speed.05 LONG SUSTAINED GRADES The maximum grade guideline is not sufficient to ensure uniform roadway operation. a climbing lane should be considered when. 2011 Version 2.0 Part 2 – Section 200 Page 19 of 32 November 2014 . when superimposed the superelevation and profile grade Version 2.To establish the grade of a structure constructed with a falsework opening. This reduces the number of sight restrictions. confusion and wrong-way movements could result if the pavement of the far roadway is obscured because of excessive differential. The minimum desirable longitudinal slope for bridge deck drainage is 0. 2011. any appreciable grade differential between roads should be avoided in the vicinity of at-grade intersections. Bridge Deck Drainage – Vertical alignment design requires special consideration of structure drainage. Exceptions to this may be minor differences between opposing grade lines in special situations. The use of separate grade lines provides the opportunity to optimize the vertical alignment. For specific details refer to AASHTO “A Policy on Geometric Design of Highways and Streets”. makes profile changes less apparent and results in a pleasing appearance.ROADWAY DESIGN MANUAL 204. for either interim or ultimate primary roadways. In addition.  The minimum vertical falsework clearance over primary and secondary roadways shall be 6.06 STRUCTURE GRADE LINE Structure Depth . The following are guidelines to be used. However. allowance must be made for the falsework depth.0m.0 Part 2 – Section 200 Page 20 of 32 November 2014 . where possible:  Vertical curves should be superimposed on horizontal curves. 205 COORDINATION OF HORIZONTAL AND VERTICAL ALIGNMENTS The coordination of horizontal and vertical alignments is based on experience and engineering judgment. 204. drainage features.07 SEPARATE PROFILE GRADE LINES Separate grade lines should be considered for all divided roadways.040 to 0. They are not normally considered appropriate where medians are less than 18m wide. and not extend more than 15m either side of the sag or crest point. Falsework Allowance . Successful coordination is essential for a safe. Parapets collect large amounts of debris and smaller bridge deck drains or scuppers have a higher potential for clogging.The depth to span ratio for a structure is dependent on many factors.045 is usually used for preliminary design purposes. A structure depth to span ratio of 0.5%. Where vertical curves on bridges cannot be avoided.  The minimum vertical falsework clearance over local roadways will be as advised by ADM. Zero gradients and sag vertical curves should be avoided on bridges. well balanced design. the elevations should be checked to provide a minimum effective longitudinal grade of 0.2%. and provide a safer more economical design. For traffic entering from the crossroad. the horizontal curve should overlap the vertical curve. Version 2.  Avoid excessive curvature to obtain flat grades and tangent alignment or flat curves at the expense of steep or long grades.The minimum taper rate to add a lane should be 25:1. confusing drivers at night. In such situations edge of pavement profiles should be plotted and smooth curves introduced to eliminate distortion. where W = Dropped Lane Width (m).  Avoid sharp horizontal curvature at or near the top of a crest vertical curve.0 Part 2 – Section 200 Page 21 of 32 November 2014 .ROADWAY DESIGN MANUAL combination may distort the outer pavement edges.6WV. This condition makes it difficult for the driver to perceive the curve. Lane Addition . Decision sight distance shall be provided at all lane drops. and V = Design Speed (kph). especially at night when headlights do not illuminate the curved roadway. 206 PAVEMENT TRANSITIONS 206. Lane Drop .  Horizontal and vertical curvature at intersections should be as flat as physical conditions permit.A typical transition between 4 lanes and 2 lanes is shown in Figure 200. The alignment and the unspecified radius of curvature vary depending on median width and other site considerations. Transitions should not occur within at-grade intersections and should be avoided in locations with sight distance restrictions. The succession of humps is unattractive.02 TRANSITIONS FOR MULTI-LANE ROADWAYS Four Lanes to Two Lanes . especially at night.  Avoid successive changes in profile which are not associated with horizontal curves. alignments should be designed to take full advantage of scenic opportunities. but in no case shall the taper length be less than 50m. It is better to balance horizontal and vertical alignments.  For moderate changes in horizontal alignment at grade summits. The transition should be on the right so that traffic merges left.08. If feasible.01 GENERAL A pavement transition occurs when changing from one roadway cross section to another. 206. the transition should occur on a tangent section and be entirely visible to the driver.The minimum taper length for a lane drop should be equal to 0.  Avoid sharp horizontal curvature at or near the low point of a sag vertical curve. Foreshortening of the horizontal curve and high approach speeds may result in erratic operation.  In general. Version 2.01 CLEAR WIDTH The clear kerb to kerb width of all bridges or grade separation structures shall equal the sum of the full travelled way approach width.2m. paved shoulders and barrier offset (if any) with the following exceptions:  Bridges to be constructed as replacements on existing dual 2-lane divided roads shall not have less than a 10m wide roadbed for ADT less than 400 and not less than 12m wide roadbed for ADT greater than 400. the minimum offset on each side shall be 1.0 Part 2 – Section 200 Page 22 of 32 November 2014 .08 Typical Two-Lane to Four Lane Transitions 207 BRIDGES AND GRADE SEPARATION STRUCTURES 207.2m.ROADWAY DESIGN MANUAL Figure 200.  When the approach shoulder width is less than 1. Slip resistant finishes are expected on sloped surfaces (6% or greater). refer to both the Abu Dhabi “Public Realm Design Manual” (PRDM) and the Abu Dhabi “Urban Street Design Manual” (USDM). The crown is normally centered on the bridge except for one-way roadways where a straight cross slope in one direction should be used.3% (1 in 12) gradient.The minimum sidewalk cross slope should be 1.02 CROSS SLOPE The cross slope shall be the same as the approach pavement.ROADWAY DESIGN MANUAL The width should be measured normal to the centreline between faces of kerb or railing measured at the gutter line. For current standards and details with regards to Pedestrian Facilities.07 should be used to determine sidewalk width.5% towards the roadway. Sidewalk pavers should be made of high quality material with low water absorption and decorative stone chips. 208 PEDESTRIAN FACILITIES 208. Sidewalk Widths . rather than relying solely on pigmentation.The guidelines in Table 200.0 Part 2 – Section 200 Page 23 of 32 November 2014 . Figure 200. Cross Slope .09 Pedestrian Realm Zones Version 2. Pedestrian crosswalk ramps shall be located at all intersections and all other locations where main pedestrian traffic crosses kerblines.01 SIDEWALKS Refer to ADM tiling strategy for selection of sidewalk pavers. 207. Longitudinal ramps (pedestrian ramps) should not exceed a maximum of 8. 8 .0 Street 2.5 Boulevard 2. Surfaces should not be interrupted by steps or abrupt changes in level of more than 6mm.0 Access Lane 2.0 – 3. Changes in sidewalk level due to various building entrance levels (for the existing buildings) should be fixed or mitigated by engineering solutions.0 Access Lane 2.0 – 2.5 Avenue 2.4 – 3.5m if buses use kerb lane as part of a regular transit route.0 – 2.4 Access Lane 2.ROADWAY DESIGN MANUAL Table 200.0 – 2.0 – 3.07 SIDEWALK WIDTH GUIDELINES Area Vicinity Width Range (m) Boulevard 2.6 Avenue 2.5% and maximum cross slope to be 3%. installed and maintained to be smooth and level.0 Street 2.0 – 3.0 – 2.4.3% gradient.  Dimensions provided are assuming parallel parking.5 Avenue 2.0 – 3.  Paving should be designed.0 – 3.4 – 3. Further technical guidelines concerning the design of pedestrian facilities is given below:  Ensure sidewalks are a minimum 2m wide (obstacle free).0 – 3.4 Access Lane 2. Version 2.0 Street 2.  Longitudinal ramps (pedestrian ramps) should not exceed a maximum of 8.0 – 2.4 – 4.4 Street 2.5 Boulevard 2.0 – 3.5 City Context Town Context Commercial Context Residential Context Industrial Context Notes:  Use 3.4 Access Lane 2.0 – 3.0 – 3.0 Avenue 2.0 Street 2.0 – 2. desirable cross slope to be 1.4 Boulevard 2.4 – 3.0 Part 2 – Section 200 Page 24 of 32 November 2014 .5 Boulevard 2.5 Avenue 2. existing utilities. roadway classification. if pedestrian use is extensive. an overpass or underpass may be considered.0m.5m paved edge zone and 1.5m. Typical kerb height for Boulevards and Avenues to be 15cm and for Streets. current and future land use. but in no case shall the clearance be less than 2.  Pedestrian Crossings should be located at a maximum of 150m intervals along streets and should relate to areas where the pedestrians desire to cross. topography and the surrounding architecture. groundwater influence. If an underpass is used.  Vertical separation of pedestrian paths from vehicle travel ways should be maintained. sociological and cultural factors. mixed traffic facilities and shared cycle and pedestrian paths are shown below: Version 2. The minimum width shall be 2. crossing volumes. drainage. Established pedestrian patterns should be maintained across primary routes. 208. The choice between an overpass or underpass should be based on relative costs. If a circuitous route is involved. Justification for pedestrian grade separation structures derives from a detailed study of present and future community needs. a pedestrian separation may be justified. unobstructed visibility shall be provided through the structure and approaches. Each situation should be studied separately and the study should include pedestrian generating sources. travel patterns. 208.04 CYCLE TRACKS The key principles for shared lanes.0m. Where possible sidewalks along the travelled way edge should be eliminated and shifted to the building frontage while retrofitting streets as per the USDM.5m landscape zone.03 PEDESTRIAN UNDERPASSES Underpasses require special consideration due to visibility issues and the potential for criminal incidents and vandalism. location/circuitry of adjacent crossings. Special consideration should be given to school crossings. Separate pedestrian structures should be provided if vehicular crossings are inadequate for pedestrians.  Sidewalks should be separated from travelled ways by a minimum of 0. land uses.ROADWAY DESIGN MANUAL  Provide pedestrian ramps at access locations to underground parking facilities (if not provided by the building owner) in order to avoid steps for pedestrians. Access Lanes and Frontage Lanes to be 10cm. The desired vertical clearance is 3. and the predominant type and age of users. 208. However.02 PEDESTRIAN GRADE SEPARATIONS Pedestrian grade separations are not normally provided on roadways.0 Part 2 – Section 200 Page 25 of 32 November 2014 . visibility. ROADWAY DESIGN MANUAL Key principles for cycle lanes are as follows:  A Cycle lane is a one way cycle facility marked on a road surface. signs and road markings. with no demarcation between different modes.  Cyclists have exclusive use of the cycle lane. geometry. Key principles for shared cycle and pedestrian paths are as follows:  Separated from trafficked roads off the rightof-way.  Generally used on roads that have low traffic volumes and traffic speed (less than 45 kph 85th percentile speed). refer to the ADM Standard Drawings.  Presence of shared lane is reinforced with additional road markings showing a bicycle and direction of travel.  Separation buffer should be used where cycle lanes are located alongside on street parking. Key principles for shared and mixed traffic facilities are as follows:  Cyclists share the road with other users.  Shared use facility should be a minimum width of 3m with signage to designated shared use area. clear and legible design to promote consistent and considerate behaviour from all users at all times.  Corridor width should more than 11 metres with a minimum carriageway width of 6 metres.  Located on local roads which are not wide enough to accommodate cycle lanes.0 Part 2 – Section 200 Page 26 of 32 November 2014 .  Segregated paths should have a dimension of 2m (minimum 1.  Where the carriageway is less than the corridor allowance then cyclists should make use of the shared lane proposal shown below.8m for pedestrian footway. Version 2.5m) for cycle track and 1. Further details can also be found in the “Abu Dhabi Walking and Cycling Master Plan” published by the DoT.  Coherent. For key design applications.  Located on local roads with low volume and speed of traffic. Kerb Upstand .02 Standard kerbs. and regulate and control parking. The following colours are used: Grey : Blue/black stripe: Blue/white stripe: Yellow/grey stripe: Yellow: Red: Blue: 209.This kerb is used between pedestrian pavers and green areas. Kerb Type D .Typical kerb upstand to be 150mm for Boulevards and Avenues and 100mm for Streets.ROADWAY DESIGN MANUAL 209 KERBS 209. Kerb Types A and B . roundabouts and traffic separation islands. Access Lanes and Frontage Lanes. Kerb Painting – Kerb painting in Abu Dhabi varies dependent upon the area and denotes parking classifications and restrictions.  Protect the roadway fence on frontage roads. Visibility marking (junctions. delineation. The reasons for providing kerbs include the following:  Provide proper drainage.This kerb is used between the road pavement and pedestrian crossings.  Protect pedestrians and provide continuity at ramp connections with local roads. where required.0 Part 2 – Section 200 Page 27 of 32 November 2014 . or improving traffic flow and safety.  Replace existing kerbs. Parking for disabled persons. Kerb Type E .This kerb is flush with the pedestrian pavement and used as an interface between different types of pedestrian pavers. Intersections. Parking prohibited (adjacent to fire hydrants). TYPES AND USES Precast kerb types and uses are shown on the Standard Drawings and are discussed below. Parking area (standard parking charges apply). No parking (to be applied at sectors where paid parking is operated). entry/exits).  Channelization. Kerb Type C . control of access. control drainage. The choice of kerb is dictated by the road classification and application.01 GENERAL Kerbs will be provided along all edges of pavement in urban areas. New kerbing is not to be painted grey. Version 2. Parking area (premium parking charges apply).These kerbs are used to deter vehicles from using areas outside the travelled way. 0 Part 2 – Section 200 Page 28 of 32 November 2014 .These high-upstand kerbs were commonly used in Abu Dhabi prior to directives issued in 2007. Kerb Types G.  Bus bulb stop. All roadway width dimensions are measured to the front face of the kerb. This shall be connected to the nearest pedestrian route. 210 BUS STOPS AND TAXI STOPS In urban areas.8m.ROADWAY DESIGN MANUAL Kerb Type F . a sidewalk shall be provided in accordance with UPC street furnishing requirements.Kerbs should be positioned to provide the same unobstructed roadway width that is normally provided. H and I . Version 2. the kerb should transition from normal kerb height to zero in 3. To prevent ponding in bus and taxi stops on flat grades use either a reverse cross slope towards the main road pavement with slotted trench drains or continue the slope of the roadway and install an inlet along the loading/unloading kerb line.03 KERB PARAMETERS Placement . 209.01). bus stops and taxi stops will be provided on all main roads. Details are retained for information in the case of maintenance works involving existing kerbs.  Bus stop with layby. However. with a minimum 2m width provided for the safe passage of pedestrians (also refer to the notes below Table 200.A transition from one kerb type to another shall be done over a length of between 1.0m.This kerb is flush with the road pavement and used to separate asphalt roads and parking areas from interlocking vehicular pavement. At kerb termini. Typical layouts for bus stops are provided for both layby and kerbside types. under restrictive conditions these Standards may be reduced. 210.2m and 1. Tyre-Friendly Kerb . Transitions . but any such deviations require justification and subsequent approval from the DoT.This kerb is used at the interface between bus stop layby and the adjacent sidewalk.01 BUS STOPS Bus stops are to be installed as shown on the ADM Standard Drawings and to the requirements of the DoT. Note that public transport facilities are controlled by the DoT and reference should be made to the relevant DoT regulations. At all bus stops. which is derived from the DoT. Aisle widths for 2-way roads should be a minimum of 6. Parking areas located parallel to. Parallel bays should be a minimum of 6. See Table 200.0m (parallel and up to 45º angled parking).5m. diagonal parking is preferred.5m x 2.08 below. although a length of 6. 5. This dimension Version 2.ROADWAY DESIGN MANUAL  Kerbside bus stops. 4.0m for perpendicular parking. 4. Independent parking lots developed off local roads. but physically separated from the main road. based on the International Building Code (IBC). These should be located at an offset as shown on the ADM Standard Drawings. the moving lanes of the local road also serve as the aisle. from 4. A sufficient number of parking spaces for disabled persons should be provided. The following guidelines should be followed with regards to the design of parking facilities: 1.02 TAXI STOPS Refer to the ADM Standard Drawings and latest guidelines from DoT for specific layout details. with specific layout details provided in DoT Technical Circular DOT-PT-GEN-LET-12-0005. On-street parking spaces.0m may be used if the parking bay is not adjacent to a main circulatory route. Parking structures. sufficient off-street parking facilities should be provided to avoid the need for kerbline parking along primary roadways and main roads. In the case of onstreet parking. 6.0m. For one-way roads. 2. 2. 3.01 GENERAL Parking facilities are of four general types: 1. Minimum aisle widths for 1-way roads vary dependent upon associated parking provision. Minimum parking bay dimensions for perpendicular and angled parking is 5. Guidance on bus stops can be found in the USDM. 211 PARKING To maximize the effective capacity of roadway improvements. 4.7m. developed adjacent to the travelled lanes of local roads. 211. 210. Each facility consists of an “aisle” area and a “standing area” (parking stalls). Wheel stops (100mm upstand) should be used to avoid cars overhanging walkways.5m for 60º angled parking and 6. 3. Parking spaces for disabled persons should be located as close to building entrances and facilities as possible.0 Part 2 – Section 200 Page 29 of 32 November 2014 .5m x 2. 001 and over 20.g. Reference should also be made to Department of Transport guidelines. the volume of traffic using the parking area and any sight distance restrictions. Table 200. such as volume and speed of the traffic.100 4 101 – 150 5 151 – 200 6 201 – 300 7 301 – 400 8 401 – 500 9 501 – 1. walls. plus 1 No. Consider parking spaces for bicycles and motorcycles.02 PARKING AREAS The minimum safe distance from a main road intersection to a parking entrance or exit will be dependent on many factors. The parking area edge nearest buildings should be set parallel to the building line and at a sufficient offset distance to allow inclusion of a sidewalk adjacent to the building.0 Part 2 – Section 200 Page 30 of 32 November 2014 .000 Note: (1) Based on guidelines provided in the International Building Code (IBC). for each 100 or fraction thereof over 1. and/or prior to the start of the free right turn taper. 9. 211. substations. etc) or high kerbs are located close to the kerb edge. Version 2. Provide mid-block pedestrian crossing(s) for large parking areas.1m (reverse parking) where structures (e.000 2% of total 1. it is desirable to locate parking exits onto main roads about 50m prior to the start of the left turn storage lane. type of intersection. and parking entrances off main roads about 60m prior to the intersection. (2) Note the exceptions given in IBC Section 1106. width and number of lanes on the main road.ROADWAY DESIGN MANUAL should be increased to 0. Generally. Consider garbage bin locations (in consultation with the Abu Dhabi Waste Management Department) to avoid improper placement of garbage bins in parking areas. 7.50 2 51 – 75 3 76 . 8.25 1 26 .08 PARKING PROVISION REQUIREMENTS FOR DISABLED PERSONS Total Parking Bays Provided Required Minimum Number of Bays for Disabled Persons 1 .9m (forward parking) and to 1. Double entrance/exit. such as land use and proposed community developments. 211. 2. These roads are generally 2-way roads and the associated parking should be either parallel or perpendicular. Determine the need for additional parking facilities and establish approximate locations for such parking. The use of 45º parking should only be proposed on 1-way local roads. 3.0 Part 2 – Section 200 Page 31 of 32 November 2014 .05 PARKING DEMAND / SUPPLY ANALYSIS During the early stages of the Concept Design. Determine the location of all existing parking facilities in the vicinity of the project. Diagonal parking should only be used in conjunction with 1-way aisles/local roads. Table 200. Single entrance/exit. 211. the following layout rules should be applied: 1.03 ON STREET PARKING SPACES Parking spaces along local roads are provided immediately adjacent to the running lanes. published by the Abu Dhabi DoT. the designer should: 1.ROADWAY DESIGN MANUAL 211. Parking lots adjacent to each other (served from different aisles) should be separated by a raised sidewalk at least 1. Aisles and entrance/exit widths should be typically designed for two-way operation in conjunction with perpendicular parking. 3. refer to the “Trip Generation and Parking Rates Manual for the Emirate of Abu Dhabi”. which should therefore be replaced. Identify any facilities which will be displaced by the road improvements.04 PARKING LOTS Parking lots are of two general varieties: 1.0m wide. for full details of all categories. This provides a sample set of parking rates for a range of development types. 2. Version 2. 2. The required analysis regarding parking will thus vary from project to project since parking demand is sensitive to site-specific factors. However.09 below indicates the parking requirements associated with different types of development. Wherever practical. 252 per 100m of GFA. 0.ROADWAY DESIGN MANUAL Table 200. Version 2. (2) These requirements should be considered as minimums. 2 School/ Company Bus/Trucks. 2 Car – Visitors.714 per 100m of GFA. 2 School/Company Bus/Trucks. 2 Car – Visitors.281 per Bed.000 per Bedroom. 0. 0.115 per 100m of GFA. 2 Car – Visitors.818 per Unit.009 per 100m of GFA.392 per Student. 1. 510 Nursery and Schools 511 Nursery / Childcare 810 Hospitals 811 Government Hospital Residential Group Institutional Group Medical Group 2 2 Car – Employees/Resident.081 per Bedroom. Car – Visitors. Car – Visitors. Office Group 210 Government Offices 211-A Local Government / Administrative Building Car – Employees/Resident. 0. 0. School/Company Bus/Trucks. Car – Visitors. 0. 0. 330 Group Accommodation 332 Labour Accommodation Car – Employees/Resident.003 per Unit. 1.0 Part 2 – Section 200 Page 32 of 32 November 2014 . 0.022 per Bed. Notes: (1) Parking rates quoted above apply to Abu Dhabi City – CBD.066 per Bed.015 per 100m of GFA. 0.704 per 100m of GFA. 0. School/Company Bus/Trucks. Parking Rate) Commercial Group 110 Shopping Malls / Centres 113-A Superstore Car – Employees/Resident. 0.080 per Student.043 per Unit. where applicable. 1.017 per Student. School/Company Bus/Trucks. 2 Car – Employees/Resident.09 Parking Requirements Type of Development (Group Name) Category Number Category Name Class Number Class Name Example of Parking Information (Type of Vehicle. 0.730 per Bedroom. 310 Apartments 311-A Studio and One Bedroom Apartments 320 Villa 321-A Standalone Villa Car – Employees/Resident. 0. 0. School/Company Bus/Trucks. 2 School/Company Bus/Trucks.016 per 100m of GFA.178 per 100m of GFA. 0. Car – Visitors. 0. 0.211 per 100m of GFA. Car – Employees/Resident. 0. ROADWAY DESIGN MANUAL SECTION 300 : GEOMETRIC CROSS SECTIONS Version 2.0 Part 0 – Divider November 2014 . GEOMETRIC CROSS SECTIONS 301 TRAVELLED WAY STANDARDS 301. soil characteristics. sustainability. 301. improve sight distance. higher driver comfort levels.0 Part 2 – Section 300 Page 1 of 33 November 2014 . 301. 302 SHOULDER STANDARDS Shoulders provide pavement structural support. Unpaved travelled ways shall have a cross slope of 3. This reduces to a standard lane width of 3. drainage considerations. climate. consistent operation and lower accident rates. A wide two-lane two-way pavement provides higher capacity. Pavement superelevation on curves is discussed in Part 2 . performance of pavements in the area. cross slopes below 1.01 TRAVELLED WAY WIDTH Travelled way width is one of the most important safety factors in design. The standard lane width for Boulevards and Avenues is 3.3m and the width of the first (edge) lane (for buses and larger vehicles) is 3.5m.02 TRAVELLED WAY CROSS SLOPES Cross slopes on straight roads should provide adequate crossfall to facilitate drainage. provide emergency stopping areas and help provide required side clearance. Storage/deceleration lane requirements associated with free-right turns shall be determined as per the right turning traffic volumes. availability of materials. Generally.0%. Note that shoulders are not used on urban streets.ROADWAY DESIGN MANUAL SECTION 300 . initial cost.0m for Streets. and the overall annual maintenance and service-life cost.01 SHOULDER WIDTH STANDARDS Table 300. required skid resistance. 302. Access Lanes and Frontage Lanes.01 summarizes the minimum continuous usable width of paved shoulders for various roadway classifications: Version 2. Superelevation.Section 202.5m lane width should be maintained for designated bus routes. Width of left turn lanes is 3. although a 3.03 TRAVELLED WAY PAVEMENT TYPE Pavement type is determined based on the traffic volume and composition.0m (minimum).5% have little effect on vehicle steering.3m (desirable) and 3. whilst avoiding excessive gradients that may influence vehicle handling. 5 6 Lanes or more 2.0m wide.5 (2) 3. Bridge Structures . Version 2.Shoulders shall be sloped at 3% away from the travelled way.0 preferable 3.Freeway/Expressways 4 lanes (1) Rural . (2) Shoulders adjacent to abutment walls.5 (2) 3. the following shoulder slopes shall be adopted: 1.Multi-lane Collector Urban .5 Rural .01 PAVED SHOULDER WIDTH STANDARDS Inside Paved Shoulder (m) Roadway Class Rural .2 2. However.0 3. in depressed medians.5 (2) Single-lane Ramp 1.5 4 Lanes Rural .Freeway/Expressways 2 lanes - (1) Rural .02 SHOULDER CROSS SLOPES In normal straight (tangent) sections.0 preferable 2. Left Shoulders – In paved median sections.5 (2) Multi-lane undivided Notes: (1) Total number of lanes in both directions.5 (2) Multi-lane Ramp 1.Boulevards 2.0 3.2 2.0 1. the shoulders shall be in the same plane as the adjacent travelled way. shoulders shall be designed in the plane of the travelled way. Source: Modified from Caltrans “Highway Design Manual” (1). these shoulders shall be sloped at 2% away from the travelled way. 2.ROADWAY DESIGN MANUAL Table 300.Freeway/Expressways 6 lanes or more (1) (2) 3.Multi-lane Collector Urban . including separate roadways.Avenues Outside Paved Shoulder (m) 2. 2012 – Table 302.0 preferable - 2. 302.1. (3) Shoulders are not used on urban streets. Right Shoulders .5 1.0 Part 2 – Section 300 Page 2 of 33 November 2014 . 3.When a roadway crosses a bridge structure. retaining walls in cut locations and noise barriers shall not be less than 3. but in no case steeper than 1:2. 3. Chapter 300.0 Part 2 – Section 300 Page 3 of 33 November 2014 . Topic 304. Version 2. The following are minimum clearances recommended for cuts higher than 10m:  6m for cuts from 10m to 15m.  One third the cut height for cuts above 25m. slopes should be flattened to be consistent with the roadway classification and topography.  7. but not exceeding 15m. If slopes are steeper than 1:3. Further details can be found in Caltrans “Highway Design Manual” (1). Economics – reduction in cross-sectional fill and land acquisition costs may play a role in slope grade choice. Aesthetics – flatter.2 – Sideslopes.01 SIDE SLOPE VALUES Embankment side slopes should be 1:6 or flatter depending on soil type. barriers may be required. 2.0m is desirable. The standards above apply to all varieties of cross-sectional cuts including. but not limited to:  Slope benches and cut widening.ROADWAY DESIGN MANUAL 303 SIDE SLOPE STANDARDS Properly designed side slopes ensure roadway stability and provide a safe recovery area for errant vehicles.0m. Safety – flatter side slopes are better suited for the recovery of errant vehicles. gently rolling slopes are more pleasing aesthetically than steep side slopes.  Stepped slopes. Erosion control – flatter side slopes are preferable to steeper ones in terms of possible damage during rain. 303. Factors affecting side slope design are as follows: 1. The top and bottom of all slopes should be rounded.02 SLOPE CLEARANCE FROM RIGHT OF WAY The minimum clearance from the right-of-way line (edge of travelled way for the road concerned) to the top/bottom of slope should be 3. Where feasible.  Contour grading and slope rounding. Cut slopes should generally be 1:3 or flatter. 303. 4. although 5.5m for cuts from 15m to 25m. 2m. Median width is the dimension between inside edges of the travelled way. etc).01 HORIZONTAL CLEARANCES Unshielded Horizontal Clearance . tram. It may require modifications in the future to accommodate such expansions for:  Public Transport (bus. except that a minimum clearance of 1. On all roadway facilities.ROADWAY DESIGN MANUAL 304 MEDIAN STANDARDS A median is the portion of a divided roadway between the opposing travelled pavements. Fixed objects within the clear zone shall be eliminated.The minimum desired horizontal clearance between the travelled way edge and fixed objects shall be the clear zone width.02 below. moved or redesigned.  Future traffic needs. Paved medians. concrete barriers. Shielded Horizontal Clearance .2m shall be provided where the standard shoulder width is less than 1. including those bordered by kerbs. 305 HORIZONTAL AND VERTICAL CLEARANCES 305. Efforts should be made to avoid decreasing the existing vertical clearance wherever possible and Version 2. if necessary for drainage. Raised medians shall be used on urban roads to regulate left-turn movements. sloping towards the sides at the slope of the adjacent pavement. Allowance for working width requirements are to be considered. Refer also to the UPC “Urban Street Design Manual” (2). rail. Slopes as steep as 1:6 are acceptable.0 Part 2 – Section 300 Page 4 of 33 November 2014 . then lesser clearance is allowed if concrete barriers or guardrails are used to shield the object. Cross slopes should be 1:10 or flatter. retaining walls or noise barriers shall not be less than the standard roadway shoulder width stated in Table 300. landscaped medians between kerbs shall be graded flat. with 1:20 being preferred. the clearance to fixed objects such as bridge parapets. should be crowned at the centre. as discussed later in this section. 305.02 VERTICAL CLEARANCES Vertical clearances to structures and other features are indicated in Table 300. Chapter 5 for relevant median requirements and cross sections. Unpaved. say 20 years after completion of construction. Median width should generally be selected based on traffic volume and speed. Other unpaved medians should slope downward from the shoulders to form a shallow valley. abutments.01.If fixed objects cannot be eliminated. moved or redesigned. including the inside shoulder. see AASHTO “Roadside Design Manual” (3). roadway curvature and superelevation may impose restrictions on the application of clear zone values.A clear zone is an unobstructed.The desirable vertical clearance shall be 6. flat or gently sloping area beyond the travelled way edge. which gives drivers the opportunity to regain control of errant vehicles and to safely stop. application of the clear zone concept is straightforward.0 Part 2 – Section 300 Page 5 of 33 November 2014 . Version 2.0 Pedestrian Overpass 6. In an area where the roadside is relatively clear. flat and straight. factors such as roadside embankments. For specific updates relating to definitions on Clear Zones. Chapter 3 – Roadside Topography.0 Overhead Communication Lines Contact the concerned authority Power Lines Contact ADWEA TUNNEL CLEARANCES Horizontal Clearance – The minimum tunnel width should equal the full approach travelled way width plus paved shoulders. In one-way tunnels. Reductions below this will only be permitted in specific instances. Table 300. For two-way tunnels.02 VERTICAL CLEARANCES Structure / Feature Type 305. Vertical Clearance .0m measured at any point over the travelled way.03 Minimum Vertical Clearance (from pavement surface) (m) Bridges 6. the minimum side clearance from the edge of the travelled way (unless sight distance dictates otherwise) should be 1.0m on the right.ROADWAY DESIGN MANUAL consideration should be given to increasing vertical clearance on projects involving structural section removal and replacement.5m on the left and 2. Fixed objects should not be located within the clear zone. if approved by ADM. if possible. space restrictions. 306 CLEAR ZONE CONCEPTS Clear Zone . along with horizontal curve adjustment factors and expanded examples of clear zone evaluation.0m on each side. The clear zone is measured horizontally from the travelled way edge to the nearest roadside obstacle.0 Sign Structures 6. However. this clearance shall be 2.0 Pedestrian Overpass with Overhead Guide Sign 6. Table 300. taking into account roadway curvature. Sharp curves significantly reduce the benefits of the clear zone values shown below due to higher roadway departure angles. These modifications should be used in locations with high accident rates and where increasing the clear zone distance is cost effective. traffic volumes and operating speeds.03.04 shows correction factors used to adjust the clear zone distances.The clear zone width required is based on side slope geometry. as shown in Table 300.0 Part 2 – Section 300 Page 6 of 33 November 2014 . Curvature Correction Factors . Version 2.ROADWAY DESIGN MANUAL Clear Zone Standard . 5 – 4.500 .0 – 3.5 – 5.  Where a site specific investigation indicates a high probability of crash continuance.0 5. All distances are measured from the edge of travelled way.0 Under 750 3.0* Over 6.5* ** 4.5 – 8.5 9.5 – 6.0 – 13.0 – 12.0 – 9.5 – 5.0 – 7.000 4.5 – 7.6. Traffic volumes will be based on a 20-year projection from the anticipated date of construction. ** Since recovery is less likely on unshielded.0 4.5 – 5.5 3.5 4.0 1.5 5.0 6.5* ** 9.5 8.0 Part 2 – Section 300 Page 7 of 33 Edition).0 2.0 – 11.0* 12.5 3.5 – 7.0 6. For clear zones.0 – 15.5* ** 4.0 – 5.0 – 16.0 – 5. 2012 (2 Version 2.0 – 15.0 – 10.500 10.5* Under 750 8.5 – 4.0m for practicality and to provide a consistent roadway template if previous experience with similar projects or designs indicates satisfactory performance.5* 100 120 140 Notes: 1. fixed objects should not be present in the vicinity of the toe of these slopes. The consultant may use a wider clear zone.5 – 4.0 ** 3.0 – 5.5 Under 750 5.0 7.0 – 3.5 – 7.0 – 6.0 – 3.5* 1.0 – 3.5 – 5.0* Over 6.1.5 – 12.5* 11.5 – 14.0 – 10.0 – 5.80 Cut Slopes 1:3 1:3 or steeper 1:4 to 1:5 1:6 or Flatter Under 750 2.5 – 4.0* 13. These are recommended clear zone distances.5 ** 4.5 750 .0* 14.5* 13.0 750 .5 1.0* ** 3.5 750 .5 ** 2.000 12.0m as indicated.0 7.5 – 8.5 – 17.0 – 3.0 3.5 – 5.0 – 3.0* ** 7.5 3.5 ** 3.500 .5 6.5 – 18.0 750 .0 Over 6.5 3.0 – 5.5 – 11.0 8.0 2.0 – 3.5 – 4. Clear zones may be limited to 9.5 7.5 7. 2.5 – 5.0 – 6.0 – 6.500 8.0 – 8.0 – 3.000 3. the “Design Year ADT” will be the total ADT for both directions of travel for the design year.5 – 5.5* 16.5 – 9.5 – 8.5 – 4.000 5.ROADWAY DESIGN MANUAL Table 300.0 8.5 – 4.000 8.0 – 10.5 – 4.0* ** 5. 3.5 Over 6.5 ** 4.0 – 3.0 8.0 – 3.5 3.500 .0 – 3.0 – 10.0 – 6.000 15.5 – 10.5 4.0 – 5.0* 18.500 3.0 6.5 – 5.5* ** 4.5 3.03 CLEAR ZONE DISTANCES (IN METRES FROM EDGE OF TRAVELLED WAY) Design Speed (kph) Fill Slopes Design Year ADT 1:6 or flatter 1:5 to 1:4 60 or less 70 .5 – 6.5 Over 6.000 13.0* ** 5.0 – 20.0 ** 2.0 – 12.0 4.5 9.0 – 12.0 – 6.5 1.0 5.5 – 4.1.0 2.5 – 5. as determined on a case-by-case basis.0* 11.0 – 7.5 6.0* 10.1.5 – 6. the designer may provide clear zone distances greater than 9.0 ** 3. nd Source: Modified from the Abu Dhabi DoT “Roadside Design Guide” (4).500 6. traversable 1:3 slopes.5 7.5 – 4.0 2.5 4.5 – 8.500 .0 ** 3.5 – 5.0 – 3.5 3.0 5.0 750 .5 4.0 – 9.0 – 7.0 – 13.5 4.1.5 6.0 10.6.5 ** 3.5 5. Table 2.000 10.0 5.0 1.500 4.5* ** 6.0 9.0 – 10.500 .5 – 6.0 – 3.5 – 8.0 10.0 – 9.5 3.0 – 10.5 5.000 6.0 – 8.0 – 5.0* 10. This applies to both divided and undivided facilities.6.0 – 3.0* 11.0 – 7.0 – 3.0 7.5 – 5.6. November 2014 .0* ** 4.000 9.5 5.5 – 5.1.5 – 8.0 – 9.5 Under 750 6.0* ** 7.0 – 10.5 – 8.6.2.0 – 12.0 – 7.0 – 12. 1 1.1 1.2 1.1 1.2 1.3 1.4 - 400 1.2 1.3 - - 300 1.ROADWAY DESIGN MANUAL Table 300.03 (m) The calculated CZc to be rounded up to the next highest increment of 0.4 800 1.2 1. 2012. Table 2.2 1. For intermediate curve radii not included in Table 300.2 1. The applicable clear zone distance on a horizontal curve is calculated by: CZc = (Kcz).2 1.4 650 1.2 1.1 1.2 1.4 1.4 700 1.1 1.5 - - - nd Source: Abu Dhabi DoT “Roadside Design Guide” (4).04 HORIZONTAL CURVE ADJUSTMENT FACTORS Design Speed (kph) Radius (m) 60 70 80 100 120 900 1.2 1.04.3 850 1.3 - 500 1.2 1.2 1.5 - - - 100 1. m Kcz = curve adjustment factor CZt = clear zone on a tangent section from Table 300.2 1.3 - 550 1.3 1.1 1. 4.1 1.2 1.3 - 600 1. No adjustments are warranted for curve radii greater than 900m.4 - - - 150 1.2 1.1 1.3 1.3 1.2 1. (2 Edition).1 1.1 1.1 1.1 1.4 - - 250 1.4 - 350 1.1 1. Version 2.2 1.4 750 1. Notes: 1. Adjustments apply to the outside of horizontal curves only.1 1.2 1.0 Part 2 – Section 300 Page 8 of 33 November 2014 .2 1.1 1.3.3 1.3 - 450 1.1 1. 3. 2. use linear interpolation.2 1.4 - - 200 1.1 1.5m.2 1.3 1.(CZt) where: CZc = clear zone on a curve.1 1. the curve correction factor (Kcz) = 1. The toe of slope is also rounded to enable the driver to negotiate and drive across it if the vehicle reaches the base of the embankment.0 Part 2 – Section 300 Page 9 of 33 November 2014 .4 The clear zone for the curve (CZc) = (12. use 17m 306. Non-Recoverable . Embankments with slopes between 1:3 and 1:4 generally fall under this category.ROADWAY DESIGN MANUAL Example Given the following parameters. but the vehicle may not be able to slow down or stop before reaching the base.0). the side slope is called a foreslope which can be recoverable. A smooth clear run-out area with a slope of 1:6 or flatter. The top of the slope is rounded. The difference is the width of the clear runout area. This available width is then subtracted from the clear zone distance obtained from Table 300.01 below. relatively smooth and clear of all fixed-object hazards.04.03. based on the steeper embankment slope.  Design ADT = 7.0m From Table 300. non-recoverable or critical. so wheels of vehicles remain in contact with the roadway when encountering the embankment. Recoverable slopes are 1:4 or flatter.8m. stop and return to the roadway.03.  Horizontal curve radius = 750m  Flat side slope Solution: From Table 300. The width of the runout area is determined according to the available width between the edge of travelled way and the breakpoint between the recoverable and non-recoverable slopes. the minimum clear zone on the tangent (CZt) = 12.A non-recoverable slope allows an errant vehicle to drive across it. Version 2.01 306.4) = 16. in addition to the recommended clear zone distance is recommended at the base of the slope.000.01 APPLICATION OF CLEAR ZONE Roadside Terrain: Foreslope When a roadway is constructed in a fill section.A recoverable slope allows an errant vehicle to drive across it. find the clear zone adjusted for horizontal curvature:  Design Speed = 120 kph. as defined below: Recoverable .01.(1. as indicated on Figure 300. slow down. Cross slopes can be more hazardous to motorists than foreslopes or backslopes because of the possibility of colliding with opposing traffic. If the recommended clear zone cannot be practically accommodated. 306.02 Roadside Terrain: Backslope When a roadway is located in a cut section. the base of the backslope will be outside the clear zone. 2013 Critical .ROADWAY DESIGN MANUAL Figure 300. intersecting driveways and roadways. relatively smooth and clear of fixed object hazards are recommended. rock-cut or rough-sided. 306. However. installing a barrier system may be necessary.03 Roadside Terrain: Cross Slope Cross slopes can be located along medians.04 Roadside Terrain: Ditch The primary function of ditches is to prevent roadways from flooding by directing and carrying water away from the roadway. They are especially hazardous because of fixed hazards such as Version 2.01. 306.01 Clear Runout Area Source: Michigan Road Design Manual (5). relatively smooth. clear of fixed object hazards and where a vehicle can be driven across without becoming stranded. the cut slope is called a backslope. particularly in medians immediately adjacent to opposing traffic. applicable where slopes are steeper than 1:3. such as urban areas. A traversable backslope is 1:3 or flatter. In roadside sections where 1:10 cannot be accommodated.01. If the available clear zone is narrower than the recommended width or it is not practical to adjust the roadside geometry.A critical slope is one where a vehicle has a high probability of overturning. Cross slopes of 1:10 or flatter.0 Part 2 – Section 300 Page 10 of 33 November 2014 . a barrier system may be required to prevent motorists from encroaching on the backslope. if the backslope is steeper than 1:3. traversable. This type of backslope can be included as part of the clear zone.01. a maximum slope of 1:6 should be used. 2011 (4th Edition). restoration or rehabilitation. Closed drainage systems or shielding with barrier systems should be considered in situations where a ditch located in a vulnerable location has a cross section that falls outside the shaded region. Preferred ditch cross sections are traversable and free of hazards.  Low volume or low speed roads.0 Part 2 – Section 300 Page 11 of 33 November 2014 . Figure 300.  Resurfacing.02 and 300. as shown in Figures 300.03. Figure 3-6. Cross sections that fall within the shaded area are considered traversable. Version 2. Cross sections that fall outside the shaded regions are considered less desirable and should only be used in specific conditions such as:  Restricted ROW.  Rugged terrain. The ditch cross section itself can also represent a serious hazard. headwalls and culverts.02 Preferred Cross Sections for Ditches with Abrupt Slope Changes Source: AASHTO “Roadside Design Guide” (3).ROADWAY DESIGN MANUAL exposed pipes. Trapezoidal ditch profiles are preferred. However.ROADWAY DESIGN MANUAL Figure 300. Version 2. This concluded that culvert extension and grating incurred the lowest cost.4m with rounded toes. As a result. whereas guardrail protection was not recommended for any of the scenarios considered.0 Part 2 – Section 300 Page 12 of 33 November 2014 . Figure 3-7. highway designers have commonly used three safety treatments to protect errant motorists from striking culvert openings. especially if wider than 2.03 Preferred Cross Sections for Ditches with Gradual Slope Changes Source: AASHTO “Roadside Design Guide” (3). modelled using the Roadside Safety Analysis Program (RSAP). a recent study (6) estimated accident costs for a number of scenarios to establish the treatment with the lowest accident cost. which are culvert extension. guardrail protection and the application of safety grating. 2011 (4th Edition). Roadside cross-drainage culverts have been found to affect vehicle accident injury levels. 0 Part 2 – Section 300 Page 13 of 33 November 2014 . luminaire supports. Embankments that fall outside the shaded region do not warrant shielding. the following factors must be considered:  Risks involved with hitting the hazard versus colliding with the barrier. refer to the AASHTO “Roadway Design Guide” (3).e.ROADWAY DESIGN MANUAL For further guidance on the use. All these factors must be considered together when evaluating the need for barriers. 2011. However.01 BARRIER NEED The primary function of a roadside barrier is to prevent errant vehicles from hitting roadside hazards. These considerations can include any of the following:  Reprofiling of roadside topography in the clear zone to a smooth and safe cross section. if hazards are located within the clear zone. based on height and fill slope of embankments associated with constructed roadways. installation and maintenance costs of a barrier system or accident costs involving barriers. Figure 300. prior to considering barrier installation. Figure 300. efforts must be made to eliminate the hazard first. Version 2.  Costs of accidents involving barriers versus not involving barriers.04 indicates when a barrier is warranted. However. signs. hazard lateral offset and side slope geometry) to barrier need. Barrier need is based on the premise that installing a barrier will reduce the severity of an accident at that location. 4th Edition.04 does not take into account other factors such as object hazards on the embankments within the clear zone.  Extend exposed pipes.g. culverts) used adjacent to roadways. As previously stated. trees and boulders outside the clear zone. When determining barrier requirements.  Evaluating costs of installing and maintaining a barrier system versus not installing a barrier system. efforts to eliminate hazards within the clear zone should be investigated prior to considering the installation of barriers.  Remove or relocate all manmade or natural fixed obstacles such as utility poles.  Install drop inlets for roadside drainage systems. rather than exposed pipes and culverts. 307 BARRIERS 307. placement and safety requirements of cross-drainage structures (i.  Evaluating roadway design (speed and traffic volumes) and roadside design (e. Chapter 3 – Roadside Topography and Drainage Features and Chapter 5 – Roadside Barriers. culverts and install headwalls outside the clear zone. 0 Part 2 – Section 300 Page 14 of 33 November 2014 . 307. installation costs associated with flexible barriers are lower than semi-rigid and rigid barriers.  Rigid Barrier.ROADWAY DESIGN MANUAL Figure 300. Vehicles will tend to be redirected along the barrier after impact and there is a lower injury risk to occupants compared to other barrier types.9. Version 2.02 BARRIER DESIGN Roadside barriers are categorized in terms of deflection characteristics in the case of vehicular impact. Figure 2. “Roadside Design Guide” (4).04 Risk Warrants for Embankments Source: Abu Dhabi DoT. Flexible Barrier – These dissipate the energy of a crash by providing a relatively high deflection upon impact. although the latter is not currently used in Abu Dhabi City. 2012 (2nd Edition). Furthermore. and are listed below:  Flexible Barrier.  Semi-Rigid Barrier. Examples of this type of barrier include Weak-Post W-Beam and Low-Tension/High-Tension Wire Rope Safety Barrier. Blocked-Out Thrie Beam (Strong-Post) and Modified Thrie Beam (Strong-Post). but to a lesser degree than flexible barriers. for ease of reference: Table 300. Source: AASHTO “Roadside Design Guide” (3). Examples of this type of system include Blocked-Out W-Beam (Strong-Post). However. Table 5-6.905 902 0. as a result of this the injury risk to vehicle occupants is higher than the other types. This is achieved by the support posts bending and the barrier rail deforming to absorb the force of the impact. Rigid Barrier – These are designed not to deflect upon impact and contain vehicles within the road corridor. 2011 (4th Edition).952 597 1.0 Part 2 – Section 300 Page 15 of 33 November 2014 . maximum deflection values for a selection of different TL-3 barrier systems is given in Table 300. 2011 (4th Edition).905 1094 0. Version 2. Deflection of TL-2 barriers may differ from the values given above and the Consultant shall verify the maximum values associated with the type of barrier selected during the design process.000 kg sedan at 97 kph and at an impact 0 angle of 25 .952 498 Notes: 1.05 below.476 447 1. However.03). The expected dynamic deflection of different barrier systems can be found in the AASHTO “Roadside Design Guide” (3).905 754 0. Table 5-6. Examples of this type include Concrete Barriers (F-Shape and Vertical Profile). This is important as sufficient clearance must be provided to ensure that the anticipated deflection of the barrier system is less than the distance to the hazard.ROADWAY DESIGN MANUAL Semi-Rigid Barrier – These deflect upon impact. The selection of the most appropriate type of barrier will depend not only on the test level required (see Testing in Clause 307. Rigid concrete barriers are assumed to exhibit no deflection on impact.05 DYNAMIC DEFLECTION OF TL-3 BARRIERS Beam Description Single W-Beam MGS Single W-Beam Double W-Beam Post Spacing (m) Maximum Deflection (mm) 1. but also on the available distance between the barrier and the hazard. Based on field tests conducted by the Kansas Department of Transportation using a 2. Vertical Profile).ROADWAY DESIGN MANUAL 307. but taller designs are available to counteract the overturning moments of trucks with higher centres of gravity.6. Version 2. The basic roadside barrier is designed to be 810mm high. Accordingly. vehicles have a higher probability of overturning or vaulting over these rigid barriers. Figure 300. 2012 (2nd Edition).05 Roadside Barrier . Modified Thrie Beam.  Semi-Rigid : Blocked-Out W-Beam.03 ROADSIDE BARRIER TYPES AND FEATURES Roadside barrier types considered for use in Abu Dhabi include the following:  Flexible : Weak-Post W-Beam. Blocked-Out Thrie Beam. Rigid Systems .3 and 3. “Roadside Design Guide” (4).Flexible and Semi-Rigid Systems (dimensions in millimetres) Source: Abu Dhabi DoT. Figures 3. Studies (7) have shown that vehicle stability after hitting a concrete barrier is highly dependent on the shape of the front face of the barrier.Concrete barriers are a rigid system designed to redirect vehicles with minimal or no deflection. except for locations that do not provide adequate lateral clearance for the anticipated barrier deflection.05 below provides examples of these types of barriers: Figure 300.06 below (see Types I and II). the profile of the front face of the lower portion of the barrier shall be as shown on Figure 300. Flexible and Semi-Rigid Systems – These may be installed in locations that warrant a barrier system.  Rigid : Concrete Barrier (F-Shape. However.0 Part 2 – Section 300 Page 16 of 33 November 2014 . which follow the F-shape profile. this study recommends a clear lateral distance of at least 35cm from the inner face of the concrete barrier to the nearest roadside object in order to prevent severe injuries associated with head impacts given the occupant’s head has been ejected out of the side window. as they have been shown to be safer (7). Version 2.0 Part 2 – Section 300 Page 17 of 33 November 2014 . it has been found that during a vehicular impact with rigid barriers. the use of at least 35cm clear lateral distance even when F-shape barriers are provided will ensure a safer design.ROADWAY DESIGN MANUAL However. It is believed that this required clear lateral distance could be smaller for crashes involving F-shape barriers. Type III) may also be considered as an alternative solution. since there is no strong evidence to validate this belief.06. As a result. However. the Consultant must take head ejection envelopes into consideration when determining the safe placement of fixed objects on top of or behind rigid concrete barriers. The recommended 35cm clear lateral distance was based on crash-tests using the vertical barrier profile. an occupant’s head is often ejected out of a side window. Based on its findings. which may result in contact with the barrier or an object attached to it. These types of impact event are often fatal. Research has been conducted to identify what would be the safe lateral distance from the inner face of the concrete barrier to the nearest object hazard in order to prevent contact between the vehicle occupant’s head and the barrier itself. Vertical profile concrete barriers (see Figure 300. as well as between the vehicle occupant’s head and the hazard placed near or on top of the barrier (8). Barrier testing shall be in accordance with the latest version of the AASHTO “Manual for Assessment of Safety Hardware” (9).0 Part 2 – Section 300 Page 18 of 33 November 2014 .06 below provides the basic testing parameters currently being used for barrier test levels TL-1 to TL-6: Version 2. (MASH).ROADWAY DESIGN MANUAL Figure 300. Table 300.06 Roadside Barrier – Rigid Systems (dimensions in millimetres) Testing . 270 50 25 Passenger Car 1.000 80 15 TL-1 TL-2 TL-3 TL-4 TL-5 TL-6 Source: AASHTO “Roadside Design Guide” (3).0 Part 2 – Section 300 Page 19 of 33 November 2014 .000 90 15 Passenger Car 1.270 70 25 Passenger Car 1.100 100 25 Pick-up Truck 2.100 100 25 Pick-up Truck 2.100 70 25 Pick-up Truck 2.100 100 25 Pick-up Truck 2. 2011 (4th Edition). Selection of the appropriate test level (TL-1 to TL-6) to be adopted for a particular site requiring barrier installation shall be made based on the anticipated traffic characteristics. For example.000 80 15 Passenger Car 1.100 50 25 Pick-up Truck 2. roads with a high proportion of Single Unit Trucks would require a barrier system which conforms to TL-4. The use of TL-5 or TL-6 would largely depend on the proportion of higher speeds and larger vehicle mass vehicles being present in the traffic composition.06 TEST LEVELS FOR BARRIERS MASH Test Level MASH Test Vehicle Designation and Type Test Conditions Vehicle Weight (kg) Speed (kph) Angle (degrees) Passenger Car 1.270 100 25 Tractor-Van Trailer 36.270 100 25 Passenger Car 1. Table 5-1(a).ROADWAY DESIGN MANUAL Table 300.270 100 25 Tractor-Tank Trailer 36. A road which displays higher speeds (say around 100 kph) but with a high proportion of small cars would be more suited to the provision of barriers at TL-3 than that of TL-1.100 100 25 Pick-up Truck 2. Version 2.270 100 25 Single Unit Truck 10. the potential vehicular impact angle also increases. which is dependent on operating speeds and traffic composition of the roadway. The working width area has to be free of any obstructions when the barrier is fully deflected under crash conditions. decreases accident frequency and minimizes injury severity. Controlled lateral deflection associated with a barrier system is generally acceptable. Consideration needs to be given to the amount of barrier deflection under test conditions with roadside hazards being located beyond the specified working width or maximum deflection zone. as the distance between the edge of travelled way and the barrier increases.0 Part 2 – Section 300 Page 20 of 33 November 2014 . Generally. All transitions between different barrier types and systems shall be tested and approved and have met the performance criteria of MASH. This allows drivers space to regain control of their vehicle and possibly avoid an accident. this deflection and additional vehicle rotation over the barrier must be considered when selecting a barrier system for a particular site.Transitions shall be properly designed to avoid situations where vehicles may pocket or snag on stiffer sections. providing larger or longer posts or strengthening the barrier (such as the use of nested rails). It is important to note. the length of the transition shall be 10 to 12 times the difference in the lateral deflections of the two adjoining systems. however.ROADWAY DESIGN MANUAL Transitions . For example. Barriers which expose motorists to high impact angles tend to produce unacceptably high injury levels. 2011. It is therefore a standard rule that the barrier system shall be placed as far from the edge of travelled way as possible. A barrier system shall shield the motorist from roadway hazards.07 below demonstrates the deflection of barriers and the working widths required: Version 2. due to deflection of a more flexible system. refer to Chapter 7 of the AASHTO “Roadside Design Guide” (3). which can be achieved by reducing post spacing. this is the case where a semi-rigid approach barrier joins a rigid barrier. Safety performance should meet the appropriate test level criteria. An example of a transition from a W-Beam to a concrete barrier is included in the ADM “Standard Drawings” and is based on reference (10).04 307.04.01 ROADSIDE BARRIER PLACEMENT Lateral Placement Placement of a barrier system shall be determined in a manner that increases motorist safety. Figure 300. For more information on transition designs. Placement of the barrier system should take into consideration working widths and deflection relative to the shielded hazard or protected work zone area. 307. The transition should be designed to provide a gradual stiffening of the overall approach protection system. However.  Design speed 70 kph to 80 kph. in situations where there are no feasible alternatives but to use roadside barriers offset laterally from kerbs. This holds true for all barrier systems.04. Face of barrier to be at least 2. TD 19/06. The wheels of an errant vehicle should remain in contact with the ground and its suspension system neither compressed nor suspended at the moment of impact with the barrier. Locations of roadside kerbs and slopes require particular attention when determining barrier design and placement. if installed flush with the face of the barrier for design speeds up to 80 kph (or 100mm upstand kerb height or less for design speeds in excess of 80 kph). A Strong-Post W-Beam guardrail system can be used with a 150mm upstand kerb or less. Kerbs .0m from face of kerb. August 2006.0 Part 2 – Section 300 Page 21 of 33 November 2014 .5m from face of kerb. 307.Guardrail/kerb combinations are highly discouraged in locations where high-speed and high-angle impacts are likely to occur. Kerbs have limited restraint capabilities and can cause a vehicle to vault over a barrier placed above or beyond it. Maximum kerb upstand height 100mm.02 Effects of Roadside Terrain The profile between the edge of travelled way and the barrier can have significant effects on the final placement of the barrier. Figure 1-1.ROADWAY DESIGN MANUAL W = Working Width D = Maximum Deflection Figure 300. Version 2. the following guidelines should be followed:  Design speed less than 70 kph. Maximum kerb upstand height 150mm.07 Demonstration of Deflection of Barriers and Working Widths Required Source: Based on the Highways Agency (UK) “Requirement for Road Restraint Systems” (11). Face of barrier to be at least 4. However. 000 1.As previously mentioned.04.03 Barrier Length Design Runout Lengths (LR) and Hazard Lateral Distance (LA) . 2011 (4th Edition). Table 4. guardrail performance is affected by the vehicle’s position at the moment of impact. Its distance is measured from the point the vehicle is assumed to leave the roadway to the hazard ahead.Runout Length  LA .10.000 .5. the two primary factors that must be considered are:  LR . Slopes .Hazard Lateral Distance The runout length (LR) is the distance.000 140 150 140 125 110 120 125 115 100 90 100 91 76 64 61 80 70 58 49 46 60 49 40 34 30 nd Source: Abu Dhabi DoT “Roadside Design Guide” (4). Runout length requirements vary according to the roadway design speed (see Table 300.07 RUNOUT LENGTHS Design Speed (kph) Runout Length (LR) for Given Traffic Volume (ADT) (m) > 10. Crash tests show that roadside W-Beam barriers perform most effectively when installed on slopes of 1:10 or less and are not to be used on steep slopes. Refer to the AASHTO “Roadside Design Guide” (3). November 2014 . Kerbs should only be used on higher speed roadways when concerns about drainage make them essential.000 < 1.ROADWAY DESIGN MANUAL For design speeds above 80 kph. For more detailed information on kerb-guardrail combinations.0 Part 2 – Section 300 Page 22 of 33 Edition).000 5. refer to NCHRP Report 537 (12).1. only use 100mm high or shorter sloping-faced kerbs flush with the face of the barrier. Table 300. 2012 (2 Version 2. parallel to the roadway.When designing the length of a barrier. prior to hitting a hazard (see Figure 300.000 . which a vehicle may require to stop after leaving the roadway.01).7). 307. If the hazard extends beyond the clear zone. In addition. such as an embankment.08 RUNOUT LENGTHS FOR DIVIDED FREEWAYS Runout Length ft (m) Speed Limit mph (kph) Left Side (Median) Right Side (Roadside) 80 (129) 375 (114) 315 (96) 75 (121) 314 (96) 279 (85) 70 (113) 253 (77) 242 (74) 65 (105) 176 (54) 206 (63) ≤ 60 (97) 100 (30) 170 (52) Source: “Phase 1 Assessment of Guardrail Length-of-Need” (13) Table 41. runout length and flare rate (if any).The barrier length-of-need (X) is the portion immediately ahead from the hazard and parallel to the roadway. river. Guardrails which are too long are more expensive to install and produce higher expenses associated with repair costs. The length-of-need is dependent on the hazard lateral distance. are excessively long. the lateral distance should be extended to the edge of the clear zone. However. guardrail lateral offset. the minimum lateral distance would only be to the edge of the clear zone.0 Part 2 – Section 300 Page 23 of 33 November 2014 . The hazard lateral distance (LA) is the distance between the edge of travelled way to the back of the hazard. findings of a recent study (13) into guardrail runout lengths carried out for the Wisconsin Department of Transportation suggests significantly shorter runout lengths should be used.ROADWAY DESIGN MANUAL However. if the hazard is a point obstacle. The recommended guardrail runout lengths for right and left sides of divided freeways are shown in Table 300. Barrier Length-of-Need (X) . It is of variable length. and shall be at least as long as the flared section of the barrier. calculated using the 2011 runout length values. excessively long guardrail installations tend to increase crash frequency which can oiutweigh the benefits of reduced injury levels produced by hazard shielding. slope or culvert.08. selected by the designer. if the hazard is continuous or spans larger distances. Version 2. The study suggests that guardrail length-of-need on divided freeways with relatively flat sideslopes. Table 300. 3. 1 6.e.09. LA = Distance from edge of through travelled way to lateral extent of obstruction. X = LA + (b/a). L2 = Barrier Lateral Offset. 1 becomes: X = LA + L2 LA/LR Version 2. 2.(L1) – L2 (b/a) + (LA/LR) Equation No.08 or 300. the maximum recommended flare rate should not be exceeded. 2011 (4th Edition). Calculation of Length-of-Need: 1. up to the design clear zone at each site. 2 November 2014 . Y = Distance from edge of through travelled way to end of barrier need. Select a runout length (LR) from Table 300. Select an appropriate LA as it is a critical part of the design process. If the barrier is flared away from the roadway. This distance should include all features or hazards that need to be shielded.08 Barrier – Layout Diagram and Calculations Source: AASHTO “Roadside Design Guide” (3). 4. Calculate the Length-of-Need (X) from Equation No. i. 5. For parallel installations. a:b = Flare Rate Figure 300. If a semi-rigid barrier is connected to a rigid barrier. L1 = Barrier Tangent Length.0 Part 2 – Section 300 Page 24 of 33 Equation No. Table 5-39. L3 = Obstruction Offset. the tangent length should be at least as long as the transition section. Equation No. LR = The theoretical Runout Length needed for a vehicle leaving the roadway to stop.ROADWAY DESIGN MANUAL X = Barrier Length-of-Need. Lc = Distance from edge of through travelled way to outside edge of the clear zone. no flare rate. Select tangent length (L1). 1. if needed.  Downstream length. The greater the flare rate. Flare Rate (a:b) . not separated by a median or a median barrier. especially on foreslopes and for procedures to follow for the calculation of the Length-of-Need on horizontal curves. the greater the vehicular impact angle.  Lower barrier implementation cost. The recommended flare rates are shown in Table 300. as this increases the potential angle of impact.  Reduce the perception that the barrier is a hazard  Minimizes the risk of vehicular impact due to the larger lateral offset. Therefore. This is particularly dangerous if the roadway has two-way traffic.ROADWAY DESIGN MANUAL Barrier Tangent Length (L1) – Barrier tangent length depends on the following factors:  Barrier length-of-need. This offset is also selected by the designer and shall be as far away from the edge of travelled way as possible.09. The main advantages of using flare are as follows:  Reduces the barrier length-of-need. 2011 (4th Edition).  Minimize a driver’s reaction to the introduction of an object near the travelled way.The barrier’s lateral offset (L2) is the distance between the edge of travelled way to the barrier.08 for a typical barrier layout diagram and the procedures used for the design of barrier installations. Sharp flares should not be used on the outside of curves.  Hazard width.0 Part 2 – Section 300 Page 25 of 33 November 2014 . Version 2. Barrier Lateral Offset (L2) . particularly in locations with two-way traffic. For further guidance on barrier placement. flatter flare rates should be used. increasing the magnitude of injuries particularly with rigid barriers. This provides an unobstructed recovery area to allow an errant vehicle to gain control without colliding with the barrier. Barrier flares can also increase the probability that an impacting vehicle will be redirected across the roadway and into oncoming traffic. See Figure 300. This may increase the severity of the crashes. Keeping flare rates as flat as practicable preserves the barrier’s redirectional performance and minimizes the angle of impact. refer to the AASHTO “Roadside Design Guide” (3). Flared barrier sections have their disadvantages.The flared portion of the barrier which is not parallel to the roadway. 3. including the following:  Flexible : Weak-Post W-Beam. 2012 (2 307. Tables 4.  Rigid : Concrete Barrier (F-Shape. beyond which a roadside object will not be perceived as an obstacle affecting driver behaviour. Blocked-Out Thrie Beam.02 Median Barrier Types and Features There are several types of barriers that can be used in medians.05. 2. especially where relatively short lengths of barrier are used.4 26:1 18:1 14:1 50:1 80 2.01 Median Barrier Warrants The primary function of a median barrier is to prevent cross-median collisions on a divided roadway and/or shield fixed object hazards within the median.4 16:1 10:1 8:1 50:1 Notes: 1. Roadways that have wide medians may not generally warrant the use of median barriers.2 and 4.0 21:1 14:1 11:1 50:1 60 1. but the median width required will depend on the posted speed limit and traffic volume. MEDIAN BARRIERS 307.  Semi-Rigid : Blocked-Out W-Beam. Modified Thrie Beam.05 Edition). Like all types of barriers.0 Part 2 – Section 300 Page 26 of 33 November 2014 . The shy line is the distance from the edge of travelled way. Roadside barriers should be located outside of the shy line where possible. median barriers shall only be installed if colliding with the barrier is less hazardous than not having a barrier installed at all. Vertical Profile).05.ROADWAY DESIGN MANUAL Table 300. 307.2 32:1 22:1 17:1 50:1 100 2. Median barriers are warranted in locations that have a history of cross-median accidents or contain fixed object hazards. Version 2.09 RECOMMENDED FLARE RATES Design Speed (kph) Shy Line Offset (m) (see Note 1) Flare Rate for Barrier at or Beyond Shy Line Flare Rate for Barrier Inside Shy Line Rigid System Semi-Rigid System Flexible System 140 4.2 38:1 26:1 21:1 50:1 120 3. Barrier installation shall only be considered if the fixed object hazards cannot be removed or relocated to outside of the clear zone area. nd Source: Based on the Abu Dhabi DoT “Roadside Design Guide” (4). Vertical profile barriers are shown in Figure 300. “Roadside Design Guide” (4).09 below shows examples of the standard metal beam guardrail and F-Shape concrete median barrier. Figure 300.ROADWAY DESIGN MANUAL Of these.0 Part 2 – Section 300 Page 27 of 33 November 2014 . the concrete barrier is currently the most common median barrier used in Abu Dhabi. 5.09 Median Barrier . 5.6 and 5. 2012 (2nd Edition).3.06.4.7. Figure 300. Figures 5. Version 2.Types and Features (dimensions in millimetres) Source: Abu Dhabi DoT. relatively smooth and clear of fixed obstacles is desirable. the location will depend on the geometry of the ditch (i. An example of the treatment of such fixed hazards is illustrated in Figures 300.e.9 Thrie Beam Bullnose Guardrail Detailed Plans Version 2. If the full width of the median is a foreslope embankment steeper than 1:10. A median that is flat (1:10 or less). depth and width).  Traffic volume and speed. Figure 300.ROADWAY DESIGN MANUAL 307. this type of barrier may be used on one side only. However.e. In some situations. steepness. barriers shall be installed at the edge of both shoulders. If a barrier is warranted under these conditions. If the median is wide enough to accommodate cable barrier deflections. the entire median does not require a barrier system.10 and 300.11. If the median is a v-shaped foreslope embankment or a ditch warranting a barrier. there may be hazards in the median or the roadside edge that require shielding (i. bridge piers or gantry sign post uprights).0 Part 2 – Section 300 Page 28 of 33 November 2014 . if the median is roughcut. warranting a barrier. it shall generally be installed at the centre of the median. the barrier shall be installed on the higher edge of the median.10 Layout of Bullnosed Guardrails Source : Alberta Infrastructure and Transportation Drawing RDG-B5. obstructed with hazards and non-traversable.06 MEDIAN BARRIER PLACEMENT The two primary factors to consider when placing median barriers are:  Median geometry. However. They are effective in gradually slowing down and stopping or safely redirecting errant vehicles in head-on and side-impact collisions.02 Crash Cushions The main function of a crash cushion is to decrease the severity of an accident by absorbing the vehicle’s kinetic energy at a controlled rate. 307.07. Note that on undivided roads.0 Part 2 – Section 300 Page 29 of 33 November 2014 . Allowance needs to be made in the latter case for dynamic deflection of the barrier to ensure adequate clearance is provided to the hazard. due to the probability of an impact from the opposing direction.11 Treatment of Isolated Fixed Hazards Alternative solutions for the protection of fixed hazards are the use of crash cushions to shield the object and a combination of semi-rigid or rigid barriers with crash cushions to shield the barrier ends. as determined by the ADM Road Safety Team or Independent Road Safety Audit Team. bringing the impacting vehicle to a stop in such a way that reduces the risk of severe injury.07 307. which is dependent on operating speeds and traffic composition of the roadway. The leading terminal is the approach end of a guardrail installation.Trailing terminals may be either crashworthy terminals or other suitably designed and approved terminal arrangement. both ends of a barrier installation shall be considered as being leading ends. The trailing terminal is the departure end of a guardrail installation.All leading approach end terminals shall be tested and approved and have met the performance criteria of MASH. (9).ROADWAY DESIGN MANUAL Figure 300.07. Version 2. shall have a crashworthy terminal installed at their upstream end. Trailing Terminals . Fishtail/spoon and turn-down terminals are not permitted. Crashworthy is defined as having been tested. approved and met the performance criteria of the AASHTO “Manual for Assessment of Safety Hardware” (MASH). 307. However. Safety performance should meet the appropriate test level criteria. see the paragraph above regarding terminals on undivided roads. Leading Terminals .01 END TREATMENTS AND CRASH CUSHIONS End Treatments All roadside and median barriers terminating within the clear zone and/or located where they have a high probability of being hit. Certain types require anchor blocks. a life-cycle costing should be undertaken. These include bridge rail blunt ends.  Crash Cushion Characteristics The structural and safety characteristics of the crash cushion options should be carefully evaluated.  Foundations Crash cushions may need to be placed on a concrete or asphalt pavement. a crash cushion system shall be designed to achieve the following characteristics:  Stop or redirect a colliding vehicle. Final selection of the appropriate cushion is based on the following criteria:  Dimensions of the Obstruction Crash cushions can be designed to shield obstructions of practically any width and the consultant should liaise closely with the supplier/manufacturer for selection of the appropriate solution. and debris produced by impact. Version 2.  Colliding vehicle to remain in an upright position and not be violently redirected into other traffic. installation.ROADWAY DESIGN MANUAL Crash cushions shall be used to shield relatively narrow fixed object hazards that cannot be removed or relocated. as follows:  Non-Gating. without any debris penetrating the passenger compartment. This assessment will be based on traffic volume. anchorage and back-up structure needs. Non-Redirective – these do not provide redirection capabilities. The Consultant must evaluate each hazard and select the most effective and appropriate crash cushion system for that particular situation. providing full redirection capabilities along its entire length. Initially. for example sacrificial. reusable or low maintenance/self restoring.0 Part 2 – Section 300 Page 30 of 33 November 2014 .  Gating. Crash cushions are also commonly used at the ends of roadside and median barriers. a decision should be made on the general type of crash cushion to be used. Redirective – these will contain a vehicle and keep it in the roadway after impact. This is especially important where limited space is available in advance of the obstruction. Selection Guidelines Crash cushions can be classified based on their expected impact performance. site preparation. To properly analyse these.  Costs These include costs for initial materials. impact decelerations. bridge piers. maintenance and repair/replacement. utility poles and sign structures. but some only require a smooth compacted surface. In general. including redirection capabilities. history or predicted incidents. The selection criteria for crash cushions differ in each individual case. repair time and location with respect to the travelled way. The study grouped crash cushions in three categories according to their repair costs. Version 2.0 Part 2 – Section 300 Page 31 of 33 November 2014 . These are primarily comprised of sand barrels. However. and hazard lateral offset (i. These systems may also be impractical when placed very close to the roadway edge of high-traffic-volume roads due to sand being spilled on the roadway.ROADWAY DESIGN MANUAL Crash cushion warrants should also be based on economic feasibility. ADT at least 20. These systems present the lowest installation costs. these higher costs are offset by their lower maintenance costs. as well as concerning which crash cushion type to be used) on cost-benefit analyses. because these systems can receive multiple hits before repairs are needed. concerning whether crash cushions should be installed on a certain site. even though these crash cushions present higher up-front costs. distance from hazard to roadway edge). highspeed roads. their repair costs are lower.e. These are redirecting crash cushions which have higher installation costs. Each array should be arranged such that the lighter barrels are hit first and the heavier barrels are struck as the vehicle continues through the crash cushion. These crash cushion warrants should be based on crash cushion type and cost. ADT greater than 50. The major recommendations regarding the selection guidelines for these three crash cushion categories according to the referenced study are: 1) Low Maintenance Crash Cushions: Preferred on busy (i. Crash cushions were grouped together according to repair costs obtained from crash test results provided by system manufacturers. as well as on highway scenario characteristics such as traffic volume.e. The objective of this study was to assist highway engineers select the most cost-effective crash cushion category based on a wide range of traffic. but they may require total replacement after a hit.000). 3) Non-Redirecting Sacrificial Crash Cushions. given the fact that these systems may be able to receive multiple hits before repair is required. especially in severe head-on crashes. roadway and roadside characteristics (14). However. as the likelihood of another crash before the cushion is repaired is significant. because these systems usually make use of permanent deformation or damage of parts to dissipate energy. As a consequence. A recent study performed a cost-benefit analysis on different types of crash cushions for various highway scenarios. Also. As a consequence. requiring cleaning and often total replacement. they require immediate repair after a hit.e. highway geometry. their repair costs may approach their initial installation costs. Therefore. as shown below: 1) Low Maintenance Crash Cushions. this is an attribute that should make them even more attractive for busy.000) freeways and divided rural arterial roads (i.e. As explained before. the engineer should base his/her recommendations (i. These systems may be used to shield obstacles of different shapes since they may be arranged in different array configurations. their repair costs are higher. 2) Reusable Crash Cushions. These are redirecting crash cushions which have lower installation costs. e. This is usually free of charge and the installer will propose a safe system applicable to the particular site under consideration.000) freeways and divided rural arterial roads (i. However.ROADWAY DESIGN MANUAL 2) Reusable Crash Cushions: Preferred on lower-traffic-volume (i. being carried out in line with the relevant standards.e. periodical checks of tensioned units are required at ADM specified intervals.0 Part 2 – Section 300 Page 32 of 33 November 2014 .e. 307. Ideally the vehicle’s suspension systems should not be collapsed or extended when it collides with the crash cushion. such as AASHTO MASH (Manual for Assessing Safety Hardware). such as concrete. The chosen solution should also facilitate repair of damaged sections and future maintenance. Chapters 8 and 2 respectively. less than 5. This means that if the hazard is located further than 6 metres from the edge of an undivided rural arterial. 3) Non-Redirecting Sacrificial Crash Cushions: Not found to be economically feasible in any scenario. these warrants are based on cost-benefit procedures. This allows the crash cushion system to compress uniformly throughout the impact.000). As a result.000 veh/day and hazard lateral offset lower than 6 metres. Further details on selection guidelines and economic considerations can also be found in the most recent edition of the AASHTO “Roadside Design Guide”.000) and/or obstacles located further than 6 metres from the roadway edge. These systems also appeared to be attractive for undivided rural arterial roads with traffic volumes higher than 5. Therefore they shall be installed on hard level surfaces.08 TESTING AND FUTURE MAINTENANCE Selection and design of barrier installations should take into consideration the requirements for testing (such as deflection and pull tests). Finally. it was found that no crash cushion was warranted for scenarios containing undivided rural arterials or local roads with very low traffic volumes (i. highway engineers are encouraged to make use of engineering judgement and/or site-specific analyses. it may not be economically feasible to provide these crash cushions. 2011 (3). Version 2. Coupled with the above tests. The path between the roadway and the crash cushion shall be relatively smooth and clear of obstructions. ADT less than 20. It is recommended that design installation services from the crash cushion supplier be requested. therefore. it is encouraged that the use of these crash cushion systems should be restricted to workzone areas or temporary layouts. ADT less than 50. Placement Recommendations Crash cushion systems perform best on relatively flat surfaces. 2006. Ray. Final Report to Wisconsin Department of Transportation. National Cooperative Highway Research Program (NCHRP).. Volume 137. Journal of Transportation Engineering.C. and Eccles. (12) Plaxico.. F. M.K. K. Washington D. 2012 (2nd Edition). “Head Ejection during Barrier Impacts”. M. Sicking. K. Transportation Research Record. McGee.D. (10) Lechtenberg. “Phase 1 Assessment of Guardrail Length-of-Need”. Supplement 40.H... TRB AFB20. C. 2005. F. Orengo.L. 2012.A.K. Supplement 16.ROADWAY DESIGN MANUAL 308 REFERENCES (1) Caltrans ..L. and Sicking. 2009.. Report 537. “Guidelines for Crash Cushion Selection”. Weir. and Reid J.A. (2) Abu Dhabi UPC – Urban Street Design Manual.A... American Society of Civil Engineering (ASCE). Tiso. R. Issue 12. Sicking. 2013. K.D. Voulme 138.... University of Nebraska-Lincoln. (13) Albuquerque. Lechtenberg.. 2012. Journal of Transportation Engineering. P.B.Highway Design Manual.K. June 2013. 2309. Bielenberg. Committee on Roadside Safety Design.W.. Issue 1. Pages 1-11.K. and Lechtenberg. R. Sicking. Faller. Pages 148-164.. Transportation Research Board.. American Society of Civil Engineering (ASCE)...D.D..A.A..B. 2011 (4th Edition). Issue 2.. D. S. Journal of the Transportation Research Board No. June 2013. (14) Schrum. Pages 81-93... “Evaluating the Cost-Effectiveness of Roadside Culvert Treatments”.K. “Recommended Guidelines for Curb and Curb-Barrier Installations”. K. F. F.. (11) Highways Agency (UK) – Requirement for Road Restraint Systems. Faller. J.L.D. Pages 918-925. February 2011.. “Development and Implementation of the Simplified MGS Stiffness Transition”. K.D... “In-Service Safety Performance Evaluation of Roadside Concrete Barriers”.. (7) Albuquerque. Stolle. F. (6) Albuquerque. University of Nebraska-Lincoln. Journal of Transportation Safety & Security.L. (8) Rosenbaugh. D. (5) Michigan Road Design Manual.B.L. C.B. and Lechtenberg. (3) American Association of State Highway and Transportation Officials (AASHTO) Roadside Design Guide.K.. K. Version 2.. TRP-03-252-12. and Sicking.0 Part 2 – Section 300 Page 33 of 33 November 2014 .D. R. January 2012. TD 19/06.. S. H. D. Midwest Roadside Safety Facility. July 2014.. (4) Abu Dhabi Department of Transport (DoT) – Roadside Design Guide. Midwest Roadside Safety Facility. Council. F.. (9) American Association of State Highway and Transportation Officials (AASHTO) .B. Midwest Research Report No. and Albuquerque. R. D. TRP-03-284-13.A. F. Midwest Research Report No. Faller. Mongiardini. D. R.. Faller. Volume 5..Manual of Assessing Safety Hardware (MASH). Final Report to Wisconsin Department of Transportation. Albuquerque. December 2011. Rosenbaugh.S. ROADWAY DESIGN MANUAL SECTION 400 : AT GRADE INTERSECTIONS (JUNCTIONS) Version 2.0 Part 0 – Divider November 2014 . departing. Channelized Three-Leg Intersections . It includes the roadway and roadside facilities available for traffic movement. Intersection design is very important to the overall roadway safety and level of service.e.Channelization is often desirable for a number of reasons described later. Intersection design is a cooperative effort between roadway and traffic engineers. as many accidents and safety problems occur at intersections.01. At Grade Intersections (Junctions) is to be read in conjunction with the USDM – Chapter 6. without ramps). Well designed intersections reduce the severity of user conflicts. and the multi-leg intersection. the four-leg intersection.ROADWAY DESIGN MANUAL SECTION 400 . Where channelization is provided. 403 AT GRADE INTERSECTION TYPES There are three basic types of at-grade intersections. physical elements and economics. Junction Design. 402 DESIGN CONSIDERATIONS Intersection design affects roadway efficiency. Intersections within a basic type vary greatly.0 Part 2 – Section 400 Page 1 of 33 November 2014 . based on human factors. Operationally three-leg and four-leg intersections are preferred and multi-directional "Y" intersections and intersections with more than four legs should be avoided. Grade separations (i. depending on the intersection type. operating cost and operating speed. however the general application of at-grade intersection design is common to all. Factors in determining the type of intersection include the number of intersecting legs. and interchanges are discussed in Section 500. These different types are shown on Figure 400. Vehicles arriving.The three-leg intersection has three intersecting legs which form a “T” or a “Y”. merging. islands and turning roadways should Version 2. Intersections handle a variety of conflicts among vehicles and pedestrians. the three-leg intersection. traffic considerations. Each roadway radiating from an intersection is called an intersection leg. This section deals with at-grade intersections. design speed and the roadway classification are the principal factors used to determine intersection type. Intersection type and spacing control roadway capacity and travel time. Three-Leg Intersection . capacity. topography. whilst accommodating their varied interests. traffic patterns and desired operation.AT GRADE INTERSECTIONS (JUNCTIONS) 401 GENERAL An intersection is the area where two or more roadways connect. safety. There are three categories of roadway intersections. These movements may be handled by various means. turning and crossing traffic have to be accommodated within a relatively small area. This Section 400. Traffic volume. Often the provision for a separate lane for left turns or for through movements to bypass left-turning traffic is appropriate on two-lane highways where right-turning roadways are justified. Channelized Four-Leg Intersections . Four-Leg Intersections . The roundabout intersection is a design that can be used in lieu of the traditional three or four leg intersections. All traffic turns right to merge with traffic in the roundabout. have poor visibility. This type of intersection should be avoided if possible. whilst providing optimum crossing paths and storage for pedestrians within the proposed intersection.These intersections have more than four legs and can have several configurations. mark and signalize. Roundabout Intersections . and vehicleturning angles. For further descriptions and types see Part 2. and is difficult to sign and signalize. The oblique crossing creates problems with visibility. and are difficult to sign. The offset intersection has low capacity. Version 2. Roundabout Design. The rightangled crossing is easily signed and signalized.0 Part 2 – Section 400 Page 2 of 33 November 2014 . The right-turning roadways should be designed to discourage wrong-way entry while providing sufficient width for anticipated turning trucks. is difficult to comprehend and negotiate.Roundabout designs generally have three or four legs joining a circular roadway. Traffic continues to turn right through the circle to eliminate through and left turn movements. pedestrian safety.ROADWAY DESIGN MANUAL be designed to accommodate the wheel tracks of each vehicle movement. Multi-leg intersections are confusing.The benefits of channelization in order to segregate left turning traffic streams and through traffic for vehicle movements which exist in each of the four quadrants can be designed to the varying layouts as found in:  Right Turn Channelization with Divisional Islands and Left Turn Lanes  Channelized Four Leg Intersection with Skew Multi-Leg Intersections . poor turning angles.Four-leg intersections may be right angled. oblique or offset. Section 407. provides good visibility and is the safest to negotiate. Roundabout designs are characterized by light traffic volumes and slow speeds through the intersection. ROADWAY DESIGN MANUAL Figure 400.0 Part 2 – Section 400 Page 3 of 33 November 2014 .01 Basic Intersection Types Sheet 1 Version 2. 0 Part 2 – Section 400 Page 4 of 33 November 2014 .ROADWAY DESIGN MANUAL Figure 400.01 Basic Intersection Types Sheet 2 Version 2. diverging.skew no more than 60°).01 Basic Intersection Types Sheet 3 404 CHANNELIZATION Channelization is the separation of traffic into definite travel paths using pavement markings or raised islands. traffic control devices. Channelization should be used to:  Give preference to major traffic movements.  Reduce areas of conflict. The above leads to separation of points of conflict. Predominant moves are given priority. Control is given for such things as merging. prohibited turns are controlled and vehicle speeds are controlled to some extent.  Provide speed-change lanes and separate turning lanes where appropriate.ROADWAY DESIGN MANUAL Figure 400. Vehicle paths are confined so that not more than two paths cross at any one point. Version 2.0 Part 2 – Section 400 Page 5 of 33 November 2014 .  Cross traffic at right angles (75°-90° desirable . Intersections – 9.63 Islands. Chapter 9.  Certain ideas should be used in the design of channelized intersection areas.01 PREFERENCE TO MAJOR MOVEMENTS Wherever possible. Controlling measures should conform to natural movement paths and be introduced gradually to promote smooth and efficient operation.ROADWAY DESIGN MANUAL  Restrict undesirable movements.03 INTERSECTION ANGLES A 90° intersection provides the shortest crossing for intersecting traffic and provides the most favourable conditions for drivers to judge the relative position and speed of approaching vehicles. The minimum desirable intersection angle is 75°. preference should be given to the major traffic movements. Version 2.0 Part 2 – Section 400 Page 6 of 33 November 2014 . but these will be implemented depending on the overall unique layout and can be used as follows:  Desirable distances for merging/weaving should be maintained to downstream intersections and where pedestrians are present yields. 404. Pavement reductions lead to non-wandering vehicles and errant moves. 404. 404.  Channelization islands must not interfere with bicycle lanes at intersections. funnelling or eliminating minor movements. The use of channelization within the confines of the intersection is beneficial due to:  Vehicle paths are confined so that not more than two points cross at any one point.  Control device locations are placed to become part of the channelization process. Channelization reduces these conflicts by separating traffic movements into definite travel paths. This usually requires stopping.  Provide adequate width to shadow turning traffic. The use of Channelizing Islands is a method which can be included in intersection design and it lends itself to the above.  Enhance signal control. separates points of conflict within the intersection and clearly defines vehicle pathways. Types and uses of islands vary from channelizing to divisional islands to pedestrian refuge and details of these can be found in AASHTO “A Policy on Geometric Design of Highways and Streets”. stop or signal control use is paramount. Intersection angles less than 60° should be realigned.02 AREAS OF CONFLICT Large multi-lane undivided intersection areas are undesirable because drivers cannot predict the movements of other vehicles. 07 REFUGE AREAS Properly sized traffic islands can provide refuge for vehicles and pedestrians.05 SPEED-CHANGE LANES Speed-change lanes improve intersection safety and efficiency. Channelization can also provide a safer crossing of two or more traffic streams by permitting drivers to select adequate gaps in one traffic stream at a time. Channelization separates and clearly defines points of conflict within the intersection. The highest number of conflicts occur at intersections. adding dedicated left turn lanes removes left turn traffic from the through lanes which also increases safety and capacity. Channelization should also provide ample storage for vehicles to make the turning or crossing movements. Speed change lanes for diverging traffic should permit vehicles to decelerate after leaving the through lanes. 404. channelization is required for effective signal Version 2.08 PROHIBITED TURNS Traffic islands may be used to divert traffic streams in desired directions and prevent specific undesirable movements.04 POINTS OF CONFLICT Points of conflict occur when the paths of drivers cross. Abrupt changes in alignment or sight distance should be avoided. For example. 404.0 Part 2 – Section 400 Page 7 of 33 November 2014 . traffic signals. points of conflict should be reduced so drivers are only exposed to one conflict or decision at a time. The shadowing effect of islands provides refuge for vehicles waiting to cross or enter an uncontrolled traffic stream. grade separations and channelization.ROADWAY DESIGN MANUAL 404. increasing safety and capacity. 404. 404. Furthermore. This can be done by using stop signs. Entering traffic merges most efficiently with through traffic when the merging angle is less than 15° and speed differentials are at a minimum.09 EFFECTIVE SIGNAL CONTROL At intersections with complex turning movements.06 TURNING MOVEMENTS A separate right turning lane removes turning movements from the intersection area. That single manoeuvre causes conflict with both directions of travel. a driver making a left turn on a roadway must cross right-bound traffic and merge into the left-bound traffic stream. 404. Wherever possible. 0 Part 2 – Section 400 Page 8 of 33 November 2014 .02 DESIGN VEHICLES Intersection geometric design depends on the dimensional and operational characteristics of the vehicles involved. Version 2. 405 DESIGN VEHICLES 405.  The ADM “Standard Drawings” include details for a channelized free-right turn and typical pavement markings at intersections.  Accident records provide a valuable guide to the type of channelization needed. Semitrailer Intermediate (WB-12 and WB-15). Channelization enables sorting and storing of approach traffic for orderly movement through the intersection during separate signal phases. 405.ROADWAY DESIGN MANUAL control.10 INSTALLATION OF TRAFFIC CONTROL DEVICES Traffic islands enhance the effectiveness of. The basic design vehicles used by ADM for design purposes are as follows:     Passenger Car (P). Channelization is particularly effective when used with traffic-actuated signal controls. especially adjacent to high-speed traffic where kerbing can be an obstruction to out-of-control vehicles. Barrier kerbs should only be used where pedestrian protection is a primary concern. The evaluation of this effect is called swept path analysis and can be done by hand with turning templates or by using modern computer software such as AutoTrack or AutoTURN.01 SWEPT PATH ANALYSIS A vehicle travelling around a circular curve sweeps a wider path than the width of the vehicle. AASHTO has adopted "design vehicles" representing the various classes of commonly used vehicles. traffic control devices such as signals and signs. consideration should first be given to mountable kerbs. Single Unit Truck (SU-9 and SU-12). and provide space for.  Avoid complex intersections that present multiple movement options or decisions. The swept path for large trucks and buses can be significant and must be adequately considered in design. Dimensions and clearances for traffic control devices should be considered when sizing traffic islands. City Transit Bus (CITY-BUS).11 GUIDELINES  Hatching using pavement markings is preferable to kerbed islands. 404. 404.  Where kerbing must be used. ROADWAY DESIGN MANUAL Refer to Table 100.02: Table 400.16 10.97 5.30 ** WB-12 12.20 Notes: * The turning radius assumed by a designer when investigating possible turning paths and is set at the centreline of the front axle of a vehicle.58 8.60 14. ** Based on dimensions provided by DoT.02 entitled “Design Vehicle Types”.01 and 400.64 SU-12 15. The minimum turning radii and dimensions for these vehicles are given below in Tables 400.66 12.73 11.26 6.0 Part 2 – Section 400 Page 9 of 33 November 2014 .52 5. the CTR approximately equals the minimum design radius minus one-half the front width of the vehicle. Version 2.50 5. included in Section 102 – Design Vehicles for application guidelines dependent upon roadway classification.50 ** 11.40 4. If the minimum turning path is assumed.01 MINIMUM TURNING RADII OF DESIGN VEHICLES Design Vehicle Type Passenger Car Single Unit Truck City Transit Bus Intermediate Semitrailer Symbol Minimum Centreline * Minimum Design Turning Turning Radius Inside Radius Radius (m) (CTR) (m) (m) P 7.88 WB-15 13.39 SU-9 12.46 11.09 CITY-BUS 12. 59 16.35 – 4.02 DESIGN VEHICLE DIMENSIONS Dimensions (m) Design Vehicle Type Overall Symbol Height Passenger Car Single Unit Truck City Transit Bus Intermediate Semitrailer Overhang Width Length Front Wheelbases Rear WB1 Typical Kingpin to Centre of Rear Axle WB2 P 1.83 6.80 11.13 5.44 7.20 7.22 3.22 1.62 - - CITY-BUS 3.44 12.50 10.14 1.77 WB-15 4.80 0.35 – 4.91 0.35 - - SU-9 3.20 2.11 2.91 0.44 9.50 13.00 - - WB-12 4.44 13.91 1.87 2.04 1.60 4.0 Part 2 – Section 400 Page 10 of 33 November 2014 .79 0.81 8.76 3.70 2.38 7.87 0.ROADWAY DESIGN MANUAL Table 400.02 Basic Dimensions of Intermediate Semitrailer Vehicle Version 2.40 Figure 400.30 2.11 2.52 3.10 - - SU-12 3.11 2.11 2. Steering Angle . Off-tracking .The maximum angle of turn built into the steering mechanism of the front wheels of a vehicle. It is set at the centre of the front axle of a vehicle.” CTR . The most significant dimension affecting the swept path width of a tractor/semitrailer is the distance from the kingpin to the rear trailer axle or axles.03 Turning Characteristics of a Typical Intermediate Semitrailer Design Vehicle Definitions: Turning Radius . This phenomenon is shown in the drawing above. This angle is measured between the longitudinal axes of the Version 2. as it negotiates a turn. This maximum angle controls the minimum turning radius of the vehicle. the greater the swept path width. when the combination unit is placed into a turn. The greater this distance. Tractor/Trailer Angle .The angle between adjoining units of a tractor/semitrailer.0 Part 2 – Section 400 Page 11 of 33 November 2014 . This radius is also described by vehicular manufacturers as the “turning kerb radius.The amount of roadway width that a vehicle covers in negotiating a turn equal to the amount of off-tracking. plus the width of the vehicle.The circular arc formed by the path radius of the front outside tyre of a vehicle.ROADWAY DESIGN MANUAL Figure 400. Swept Path Width .The difference in the paths of the front and rear wheels of a vehicle. The path of each rear-ward tyre of a turning vehicle does not coincide with that of the corresponding forward tyre.The turning radius assumed by a designer when investigating possible turning paths. and the correct use and placement of traffic control devices. judgments and abilities to read oncoming conflicts. If all corners of the intersection cannot be cleared and maintained to provide unobstructed views in the approach sight triangle.ROADWAY DESIGN MANUAL tractor and trailer as the vehicle turns. the intersection shall have stop control imposed.04 (for 2-way 2-lane undivided uncontrolled roadways) and Figure 400. The maximum tractor/trailer angle occurs when a vehicle makes a 180o turn at the minimum turning radius and is reached slightly beyond the point where a maximum swept path width is achieved. Approach Sight Triangle . Further design vehicles can be found in AASHTO “A Policy on Geometric Design of Highways and Streets”. Stopping sight distances are provided at a constant value along each leg of any highway/ intersection and it enables the driver to stop in a safe manner before any conflict and subsequent accident occurs. Stopping sight distance shall be the minimum provided throughout all parts of intersections. 2011. Two types of clear sight triangles are considered in intersection design – Approach Sight Triangles and Departure Sight Triangles.. 406 INTERSECTION DESIGN STANDARDS 406.The area bound by the required sight distances along the intersection legs and the sight line connecting their ends is known as the "sight triangle". slowing or stopping manoeuvre.The driver of a vehicle should have an unobstructed view of the entire intersection.01 SIGHT DISTANCE General . Urban streets shall be designed to accommodate the occasional use of emergency vehicles (such as a fire truck). although this is not considered the general design vehicle. Version 2. Vehicular conflicts at designed intersections exist and these can be greatly reduced with the use of adequate stopping distances to points of conflict such as turning points or stop lines. Adequate sight distance should also be provided at junctions to enable stopped drivers sufficient view of the adjoining highway to make the safe decision when to cross or enter.05. Bus routes need to be discussed and agreed with the DoT. etc. and their requirements incorporated into the design. The adequate design and efficient use of control devices still relies heavily on the driver’s capabilities. See Figure 400. Unobstructed sight distance along all intersection approaches and across the included corners must be sufficient to permit drivers of approaching vehicles to perceive each other. react and complete an appropriate accelerating.0 Part 2 – Section 400 Page 12 of 33 November 2014 . Note that ‘b’ is the appropriate stopping sight distance. This point represents the point where the driver needs to take the decision to brake and stop.ROADWAY DESIGN MANUAL The vertex of the triangle on a minor road approach (or uncontrolled approach) represents the decision point for the minor road driver. This is illustrated in Figure 400. Version 2.0 Part 2 – Section 400 Page 13 of 33 November 2014 . distances ‘a1’ and ‘a2’ need to include such distances as lane widths and median widths for approaching drivers considering traffic to the left and right on the major road.05 below and as can be seen. should be such that the drivers can see any potentially conflicting vehicles in sufficient time to slow or stop before Version 2.ROADWAY DESIGN MANUAL FOR APPROACHING VEHICLE & FOR DEPARTING VEHICLE Figure 400.04 Intersection Sight Triangles (based on AASHTO “A Policy on Geometric Design of Highways and Streets”. 2011 The length of the legs of the triangular area along both intersecting roadways.0 Part 2 – Section 400 Page 14 of 33 November 2014 . the driver’s eye relative to the Stop Line can be measured as being 4. Version 2.04 and 400.5m from the edge of the major road. Departure Sight Triangle .06. enabling suitable major road stopping sight distances for the departure sight triangle to be plotted. the approach sight triangles are not needed where intersection approaches are controlled by STOP lines or Traffic Signals and in the main due to concentration of features within Abu Dhabi.0 Part 2 – Section 400 Page 15 of 33 November 2014 .05 Approach Sight Triangles (Uncontrolled or Yield-Controlled) Although desirable at high volume intersections. All corners of the intersection shall be constructed to provide a clear line of sight throughout the departing sight triangle. the appropriate sight distance along the intersecting road.The departure sight triangle is bound by the location of the stopped driver. and the connecting sight line. full approach sight triangles will be extremely hard to achieve. See Figures 400.ROADWAY DESIGN MANUAL colliding within the intersection. The driver must have sufficient sight distance along the intersecting legs to make a safe departure movement. Figure 400. To enable the Departure Sight triangle at the minor road junction. To travel across the intersecting roadway. To turn left onto the intersecting roadway.  Left-Turn Control .03.Vehicles need sufficient sight distance to adjust their speed. the driver must have adequate sight distance on the major road to permit safe departure movements.06 Departure Sight Triangles (Stop-Controlled) Intersection Controls . clearing oncoming traffic in both directions. To turn right onto the intersecting roadway by entering the traffic stream coming from the left.  Traffic Signal Control .Stopped left-turning vehicles on minor roadway must yield to opposing vehicles on major roadway.For a given speed.Vehicles on minor roadway yield to vehicles on major roadway. The three basic departure movements are: 1.The following controls apply to at-grade intersections:  No Control . 2. Stop Control . Minimum sight distances provided along the legs should be at least stopping sight distance. Departure sight triangles should be commensurate with those provided at stop controlled intersections. Version 2.All legs are controlled by either stop signs or traffic signals. Once stopped.  All Way Stop Control No Control .  Yield Control . clearing oncoming traffic from the left and entering the traffic stream coming from the right.ROADWAY DESIGN MANUAL Figure 400.Approach sight triangles should be provided at all intersection corners.0 Part 2 – Section 400 Page 16 of 33 November 2014 . Yield Control .Vehicles on minor roadway stop at major roadway.  Stop Control . the approach sight triangle is determined from Figure 400. 3.Adequate sight distance must be provided so that a driver travelling at the design speed can perceive and safely stop at the stop sign. For departure sight triangles see “Stop Control”.04 and Table 400. Right turn from the minor road Case B3 . Departure sight triangles should be used that follow the values as given in Table 400.  These distances are based on level roadways.02 INTERSECTION CONTROL The recommended dimensions of the sight triangles vary with the type of traffic control used at an intersection. with slightly different assumptions.Left turn from the minor road Case B2 . because different types of control impose different legal constraints on drivers and therefore result in different driver behaviour.0 Part 2 – Section 400 Page 17 of 33 November 2014 . stop signs or traffic signals.NO INTERSECTION CONTROL Vehicle Speed (kph) Distance (m) 20 20 30 25 40 35 50 40 60 50 70 60 80 65 90 75 100 85 110 90 120 100 Notes:  The sight triangle dimensions are determined using these distances as per Figure 400. Procedures to determine sight distances at intersections are presented below. Version 2.04 for No Control.ROADWAY DESIGN MANUAL Table 400.Intersections with no control  Case B . according to the different types of traffic control:  Case A .Intersections with No Control For intersections not controlled by yield signs.Crossing manoeuvre from the minor road Case A . the driver of a vehicle approaching an intersection should be able to see potentially conflicting vehicles in sufficient time to stop before reaching the intersection. The location of the driver's eye of the sight triangles on each approach is determined from a method the same as the stopping sight distance procedure.03 SIGHT TRIANGLE DISTANCES .Intersections with stop control on the minor road Case B1 . 406.04. ROADWAY DESIGN MANUAL Table 400.04 CASE A - SIGHT TRIANGLE LEGS Design Speed (kph) Length of Leg (m) 20 20 30 25 40 35 50 45 60 55 70 65 80 75 90 90 100 105 110 120 120 135 130 150 Notes:  Distances assume level ground.  Where the grade along an intersection exceeds 3%, the leg of the clear sight triangle along the approach should be adjusted by the multiplying sight distance factors for the values given in the following table. Figure 400.07 Length of Sight Triangle Leg – No Traffic Control Version 2.0 Part 2 – Section 400 Page 18 of 33 November 2014 ROADWAY DESIGN MANUAL Table 400.05 CASE A – ADJUSTMENT FACTORS (APPROACH GRADES) Design Speed (kph) Approach Grade (%) 20 30 40 50 60 70 80 90 100 110 120 130 -6 1.1 1.1 1.1 1.1 1.1 1.1 1.2 1.2 1.2 1.2 1.2 1.2 -5 1.0 1.0 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.2 1.2 1.2 -4 1.0 1.0 1.0 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 -3 to +3 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 +4 1.0 1.0 1.0 1.0 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 +5 1.0 1.0 1.0 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 +6 1.0 1.0 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 Turning Left on to a Major Roadway (Case B1 from AASHTO “A Policy on Geometric Design of Highways and Streets”, Section 9, Cl. 9.5.3) As it takes longer to turn and accelerate to operating speed than to go straight across an intersecting roadway, the critical sight distances are those required for turning movements. The driver must have sufficient sight distance to the left to cross the near lanes(s) without interfering with oncoming traffic. The driver must also have sufficient sight distance to the right to turn left and accelerate to a speed where oncoming traffic is not significantly impaired. Version 2.0 Part 2 – Section 400 Page 19 of 33 November 2014 ROADWAY DESIGN MANUAL Table 400.06 CASE B1 – LEFT TURN FROM MINOR TO MAJOR ROAD Design Vehicle Time Gap (tg)(s) at Design Speed of Major Road Passenger Car 7.5 Single-unit truck 9.5 Combination truck 11.5 Note: Time gaps are for a stopped vehicle to turn left onto a two-lane highway with no median and with grades of 3% or less. The table values should be adjusted as follows:  For multi-lane highways – For left turns onto two-way highways with more than two lanes, add 0.5s for passenger cars or 0.7s for trucks for each additional lane, from the left, in excess of one, to be crossed by the turning vehicle.  For minor road approach grades – If the approach grade is an upgrade that exceeds 3%, add 0.2s for each percent grade for left turns. ISD = 0.278 Vmajor tg where: ISD = intersection sight distance (length of the leg of sight triangle along the major road) (m) Vmajor = design speed of major road (kph) Tg = time gap for minor road vehicle to enter the major road (s). For the equation given above in Table 400.06 (Case B1), the associated value of tg can be taken from the time gap table and using the major road design speed, the resultant ISD can be calculated and compared to the required Intersection Sight Distance given for passenger cars in the following table. The value derived dictates the Intersection Sight Distance along the major road for a car turning left from stop. Further modifications can be made to intersection sight distances (dependent upon vehicle type) by using the curves given below for a single unit (SU) truck or combination (COMB) truck. Consideration for sight triangles needs to be given for medians of sufficient width enabling storage of larger vehicles when attempting left turns from stop across a multi-lane road. A full explanation is given in AASHTO “A Policy on Geometric Design of Highways and Streets”, Section 9, Part 9.5.3. Version 2.0 Part 2 – Section 400 Page 20 of 33 November 2014 ROADWAY DESIGN MANUAL Table 400.07 DESIGN INTERSECTION SIGHT DISTANCE – CASE B1, LEFT TURN FROM STOP Design Speed (kph) Stopping Sight Distance (m) Intersection Sight Distance for Passenger Cars Calculated (m) Design (m) 20 20 41.7 45 30 35 62.6 65 40 50 83.4 85 50 65 104.3 105 60 85 125.1 130 70 105 146.0 150 80 130 166.8 170 90 160 187.7 190 100 185 208.5 210 110 220 229.4 230 120 250 250.2 255 130 285 271.1 275 Note: Intersection sight distance shown is for a stopped passenger car to turn left on to a two-lane highway with no median and grades 3% or less. For other conditions, the time gap should be adjusted and the sight distance re-calculated. Figure 400.08 Intersection Sight Distance – Case B1, Left Turn from Stop Version 2.0 Part 2 – Section 400 Page 21 of 33 November 2014 ROADWAY DESIGN MANUAL Turning Right on to a Major Roadway (Case B2 from AASHTO, “A Policy on Geometric Design of Highways and Streets”, Section 9, Cl. 9.5.3) The right-turning vehicle must have sufficient sight distance to the left to complete its turn and accelerate to a predetermined speed before being overtaken by approaching traffic travelling at the same predetermined speed. The sight distance requirement for the right-turn manoeuvre is approximately 1.0m less than that required for the left-turn manoeuvre in “Turning Left on to a Major Roadway”. See Tables below for the required sight distance for a vehicle turning right and accelerating to 85% of the design speed before being overtaken by vehicles slowing to 85% of the design speed. Trucks will take considerably longer than passenger vehicles. Table 400.08 CASE B2 – RIGHT TURN FROM MINOR TO MAJOR ROAD AND CASE B3 – CROSSING MOVE Design Vehicle Time Gap (tg)(s) at Design Speed of Major Road Passenger Car 6.5 Single-unit truck 8.5 Combination truck 10.5 Note: Time gaps are for a stopped vehicle to turn right onto or to crossa two-lane highway with no median and with grades of 3% or less. The table values should be adjusted as follows:  For multi-lane highways – For crossing a major road with more than two lanes, add 0.5s for passenger cars or 0.7s for trucks for each additional lane, and for narrow medians that cannot store the design vehicle.  For minor road approach grades – If the approach grade is an upgrade that exceeds 3%, add 0.1s for each percent grade. ISD = 0.278 Vmajor tg where: ISD = intersection sight distance (length of the leg of sight triangle along the major road) (m) Vmajor = design speed of major road (kph) Tg Version 2.0 = time gap for minor road vehicle to enter the major road (s). Part 2 – Section 400 Page 22 of 33 November 2014 ROADWAY DESIGN MANUAL Table 400.09 DESIGN INTERSECTION SIGHT DISTANCE – CASE B2, RIGHT TURN FROM STOP AND CASE B3, CROSSING MANOUVRE Design Speed (kph) Stopping Sight Distance (m) Intersection Sight Distance for Passenger Cars Calculated (m) Design (m) 20 20 36.1 40 30 35 54.2 55 40 50 72.3 75 50 65 90.4 95 60 85 108.4 110 70 105 126.5 130 80 130 144.6 145 90 160 162.6 165 100 185 180.7 185 110 220 198.8 200 120 250 216.8 220 130 285 234.9 235 Note: Intersection sight distance shown is for a stopped passenger car to turn right onto or to cross a two-lane highway with no median and grades 3% or less. For other conditions, the time gap should be adjusted and the sight distance re-calculated. Figure 400.09 Intersection Sight Distance – Case B2. Version 2.0 Part 2 – Section 400 Page 23 of 33 November 2014 ROADWAY DESIGN MANUAL Crossing Manoeuvre from the Minor Roadway (Case B3 from AASHTO “A Policy on Geometric Design of Highways and Streets”, Section 9, Cl. 9.5.3) In most cases, the departure sight triangles for left and right turns onto the major road as described by Cases B1 and B2, will also provide more than adequate sight distance for minor road vehicles to cross the major road. However in the following situations it is advisable to check the availability of sight distance for crossing manoeuvres:  Where left or right turns or both are not permitted from a particular approach and the crossing manoeuvre is the only legal move.  Where the crossing vehicle would cross the equivalent width of more than six lanes.  Where substantial volumes of heavy vehicles cross the highway and steep grades are present on the far side of the intersection. The equation for intersection sight distance in case B1 is used once again for the crossing manoeuvre except that time gaps (tg) for B2 is taken from Table 400.08. At divided highway intersections, depending on the relative magnitudes of the median width and the length of the Design Vehicle, intersection sight distances may need to be considered for crossing both roadways of the divided road or for crossing the near roadway only and stopping in the median before proceeding. The application of adjustment factors for median width and grade is as in Case B1 For full details of resulting calculations, refer to AASHTO “A Policy on Geometric Design of Highways and Streets”, Section 9 – Intersections, Part 9.5.3 - Intersection Control. 406.03 EFFECT OF SKEW Intersection skew has no effect on sight distance requirements since they are measured along the intersecting legs. However, the sight triangle configuration is affected by skew. Care should be taken to verify that the area within the sight triangles can be constructed and maintained to provide an unobstructed view throughout the sight triangle with a 1.08m eye height on the minor road to a 1.08m object height on the major road. Skew also affects the distance a vehicle travels to cross the intersection. Heavily skewed intersections should be controlled. Highways which intersect at an angle of 60º or less, coupled with unjustified realignment for increase of intersection alignment, can lead to adjustment of the factors involved in the determination of sight distance. Each of the methods described previously are applicable to oblique angle intersections. The sight triangle exists along intersection approaches and each triangle will vary, either more or less than its associated counterparts for the right angled intersection. It still remains a necessity to ensure that each triangle is kept clear of obstructions and sight lines are maintained to ensure safe operation of the intersection under analysis. Version 2.0 Part 2 – Section 400 Page 24 of 33 November 2014 However.A left-turn lane expedites through traffic flow. Adequate sight distances need to be displayed at all sections of the intersection and this is mainly a result of horizontal and vertical design being sympathetic to the need of road users in and around the intersection.To improve left-turn visibility. It is advised that sight distance criteria for Intersections with No Control are not considered.05 LEFT-TURN CHANNELIZATION General . then consideration for extra lane widths is needed. the sight distance should be increased. The desirable length of the left-turn lane is the sum of the required storage length and deceleration length. Medians . Width . Conversely.0m should remain for pedestrian refuge and traffic control devices. If the grade is significant.0 Part 2 – Section 400 Page 25 of 33 November 2014 . Version 2. Approach Tapers . controls turning traffic movement. excluding shy distance. It is accepted that provision of traffic lanes need to be clearly visible to drivers at all times. The width is measured from the adjacent edge of travelled way. including the bay taper length.Desirable taper lengths for left or right turn lane opening on Boulevards and Avenues is 40m (minimum 30m). at-grade intersections (junctions). the time required to cross a roadway is affected by the crossing grade. The left-turn lane should be laid out such that the turning vehicle must make a definite move to enter the lane. free from any sudden appearance of conflicts and consistent in design to the surrounding road previously travelled. For stop controlled intersections. Horizontal and vertical alignments need to be considered in more detail at. and improves the intersection safety and capacity. a minimum nose width of 2. Excess width between the left-turn lane and the adjacent same-direction through lane should be treated as a painted island. If the actual path length exceeds the actual width by 3.The desirable left-turn lane width is 3.0m minimum). 406.6m or more. or near to.04 EFFECT OF VERTICAL PROFILES A vehicle descending a grade requires a greater stopping distance than one on level ground.ROADWAY DESIGN MANUAL Travel paths for certain movements within an oblique intersection will need to be modified and this is done by dividing the total widths of lanes (plus median if applicable) to be crossed by the sine of the intersection angle. a vehicle ascending a grade requires less distance to stop. understandable in terms of destination/direction of travel. When left-turn lanes are placed in raised (kerbed) medians.3m (3. grades up to 3% have little effect on stopping sight distances. 406. the left-turn lane should be placed as far to the left as possible in the median leaving only the painted or kerbed nose. Channelization of intersections can be considered for a number of reasons.The storage length should be sufficient to:  Store the number of vehicles during critical periods. Right-turn lanes improve intersection capacity and safety. including bay taper.06 RIGHT-TURN CHANNELIZATION General – Channelization can be considered for both left and right turn movements as the separation or regulation of conflicting traffic movements into definite paths of travel by traffic islands or pavement marking. Storage Length . 406. right-turn lanes should be laid out such that a right-turning vehicle must make a definite move to enter the lane. The following paragraphs describe channelizing methods and the service they provide.0 Part 2 – Section 400 Page 26 of 33 November 2014 . Generally the taper length should be 10:1. The desirable length of the right-turn lane is the sum of storage requirements and deceleration length.ROADWAY DESIGN MANUAL Bay Tapers .Storage requirements and goals are the same as for left-turns. Free Right-Turns .  Ensure the lane entrance is not blocked by standing through traffic. Special Report No 209”.0m minimum).  Storage lanes are given and pedestrian areas can be provided.3m (3.The bay taper length should be short to clearly identify the additional lane.The desirable right-turn lane width is 3. As for left-turn lanes.  Prohibited moves are controlled. Storage Length .  Avoid left-turning vehicles stopping in the through lanes. excluding shy distance.  Clearer indications of driven routes are given.Desirable taper lengths for left or right turn lane opening on Boulevards and Avenues is 40m (minimum 30m). Approach Tapers . Refer to the “Highway Capacity Manual.Uncontrolled “free-right” turns improve capacity of an intersection with a heavy right-turn demand. Transportation Research Board. The right-turn is made "free" by channelizing the turning movement outside of Version 2.The bay taper which guides the motorist into the right-turn lane is a straight line along the right edge of the travelled way. The width is measured from the adjacent edge of travelled way. Generally the taper length should be 10:1. including:  Angle and location of vehicle paths are controlled. 2010 for further discussion. Width . Bay Tapers . to ease the movements of both vehicles and pedestrians. 0 Part 2 – Section 400 Page 27 of 33 November 2014 .  Aid and protect pedestrians crossing the intersection. 407 ROUNDABOUT DESIGN 407. Kerbed islands for separating traffic streams should not be less than 1. If pedestrian refuge is required. These include Ring Junctions.ROADWAY DESIGN MANUAL the intersection controls. Storage requirements need to be considered as vehicle flow will be interrupted due to the pedestrian crossings. along with current updated ADM “Standard Drawings”.  Discourage or prohibit undesirable movements.01 GENERAL There are three main types of roundabouts.Traffic islands must be large enough to be seen and to command the attention of the driver. 406.Traffic islands are located between traffic lanes and are commonly designated using paint.6m wide and 8.8m long ramp for vehicles (max 6. They serve to:  Confine specific traffic movements into definite channels. from right-in/right-out lanes by a minimum shy distance of 0. The approach end of a kerbed island should be rounded at 0.0m radius and tapered at 15:1 to guide the driver into the channelization.0m2. Design . 2010 and UPC “Urban Street Design Manual”.07 TRAFFIC ISLANDS General . 209” Transportation Research Board.  Separate traffic moving in the same or opposite direction. Mini and Double.66%). The roundabout is used at intersecting streets with low capacity and low design speed. and from free-right turn lanes by a minimum shy distance of 0.5m.5m. Kerbed islands should be offset from through traffic lanes on Boulevards and Avenues by a minimum shy distance of 0.5m to 1. Raised pedestrian crossings at free-right turns should be 10cm high with a 1.0m long. Islands for channelizing should preferably be at least 9. Normal. Grade Separated and Signalized Roundabouts. There are other forms of roundabouts but these are variations of the basic types. Note that roundabout designs are to be checked and approved by the Version 2. raised pavement markers or kerbs. provide a minimum 2m wide island between through lanes and left turn lanes. Roundabouts should be considered when they are cost effective or increase safety over standard intersection designs. Special Report No. Refer to the “Highway Capacity Manual.5 to 1. and to accommodate anticipated volumes of pedestrians as per the required pedestrian level of service (LOS).25m. htm Note that when reading the abovementioned document. This allows two or three vehicles to enter or leave the roundabout on any arm at the same time.A normal roundabout has a kerbed island of at least 4.Geometric Design of Roundabouts”.  Roundabouts can reduce traffic speeds in existing intersections. The circulatory carriageway should be wide enough to enable two to three vehicles to travel around the roundabout whilst running adjacently. For these reasons roundabouts tend to be removed and replaced with conventional signalized intersections instead of being modified. This can be viewed from the following website: http://www. including Traffic Services Section. Section 2.0m central diameter. Normal Roundabouts . Part 3 “TD 16/07 . A normal roundabout has flared entries/exits.  It is difficult to redesign an existing roundabout to increase its capacity. the Consultant should adjust for the fact that roundabout design in the UK is based on vehicles running clockwise around the circulatory carriageway.  Roundabouts require more land than conventional intersections. In areas of high pedestrian traffic. Disadvantages . Highways Agency in the United Kingdom (UK). pedestrians can cause major problems with illegal crossings. More information about the use and design of these and other roundabouts can be found in the Design Manual for Roads and Bridges.0 Part 2 – Section 400 Page 28 of 33 November 2014 . Volume 6.  Roundabouts allow for continuous traffic flow.There are several disadvantages to roundabouts that make them less favourable than conventional designs:  Driver comprehension to right-of-way with respect to yielding to traffic flow. All approach arms can be single or dual carriageway.gov. Redesign requires adding more lanes which greatly increases the land required for the intersection.There are several advantages to roundabout design versus conventional three and four leg intersections:  Roundabouts are more efficient than signals on balanced traffic demand intersections. Road Geometry.  Roundabouts are prone to large congestion problems when traffic exceeds design capacity.uk/ha/standards/dmrb/vol6/section2. rather than anti-clockwise as is the case in the United Arab Emirates. because pedestrians are not able to walk in a clear path through the intersection. Version 2. Junctions.dft. Advantages .  Roundabouts are not well suited to pedestrian traffic. This increase in diameter also increases the design speed through the roundabout.ROADWAY DESIGN MANUAL concerned ADM Departments. 10 Normal Roundabout Typical Single Lane Roundabout Figure 400.11 below: Figure 400.0m to 4. This feature is Version 2. a double roundabout or a signalized roundabout may be a better option. encouraging higher circulation speeds. See Figures 400.0m in diameter.11 Normal Roundabout Typical Multi-Lane Roundabout Mini Roundabouts – Mini roundabouts lack a kerbed central island. This is replaced with a flush or domed circular white central island marking between 1. When this occurs.ROADWAY DESIGN MANUAL When a normal roundabout has over four arms it becomes overly large.0 Part 2 – Section 400 Page 29 of 33 November 2014 .10 and 400. Road markings are absolutely necessary and should always be applied to direct the pattern of movement.ROADWAY DESIGN MANUAL capable of being run over if the movement is unavoidable.  In areas where more than four arms are entering the intersection. compact or normal roundabouts and used in areas with unique traffic requirements such as:  Where intersection improvements are done and the roundabout eliminates the need to realign an approach road.  At intersections with unusual or asymmetrical configurations.A double roundabout is a junction comprising two roundabouts separated by a short length of link road.12 Mini Roundabout Double Roundabouts . See Figure 400.  Where single island configurations do not have enough capacity. as shown diagrammatically in Figure 400. Version 2.12 below: Figure 400. This type of junction can be designed using mini. They should only be used to improve the performance of existing junctions where limited space is available and may be applied to junctions having approach speeds of 50 kph or less.13.0 Part 2 – Section 400 Page 30 of 33 November 2014 .  The joining of parallel roads separated by an existing feature. This alternative should always be investigated using appropriate software before providing signals. can be appropriate where a roundabout cannot. for some reason.13 Double Roundabout (with short central link) A double roundabout should be designated as a single system. at all or some of the entry points. In some cases. These unique circumstances should be evaluated by an experienced traffic engineer and ADM must be informed on the decision to consider a double roundabout. The double roundabout should only be used after proper consideration and is contingent only with the approval of experienced personnel and ADM. rather than install traffic signals to particular problems. Installation of traffic signals on a part time or continuous basis. self-regulate. This should receive early attention in the design process to ensure that a lane balance on the link road exists and will require assessments of likely turning movements for the twin roundabout system. Signalized Roundabouts .  Significantly different levels of flow during peak and off-peak periods. Version 2. Reduction in the capacity of the approaches feeding the link road can limit blocking back onto the roundabouts. The link connecting the two roundabouts can in some cases be quite short and not provide enough length for lane changing or storage. it may be possible to improve the geometry of the roundabout.ROADWAY DESIGN MANUAL Figure 400.These roundabouts have traffic signals on one or more of the approach arms and at corresponding points on the circulating carriageway.  An overloading on one or more entries or imbalance of traffic flow on approach arms. since it could be both less expensive and more effective. This may be due to factors such as:  A growth in traffic flow.0 Part 2 – Section 400 Page 31 of 33 November 2014 . rather than treated as two individual roundabouts.  High circulatory speeds. where a new or improved roundabout provision is being designed. Restricting left turns at major/minor priority junctions (the manoeuvre most responsible for serious accidents) can lead to considerable inconvenience to drivers. In this case. They can also be used to provide an overtaking opportunity by having a short section of two lanes in the exit arms of the roundabout. they also have other useful purposes:  To mark a significant change in road standards.02 LOCATION OF ROUNDABOUTS In addition to the natural function of a roundabout as a junction for roads. In cases where it is necessary to provide a series of roundabouts on the same route. signing and road markings are provided correctly. however. Roundabouts should ideally be located on level ground.  They allow u-turn manoeuvres to be carried out safely (compared with major/minor priority u-turns) and can handle heavy left-turning movements. Roundabouts can be sited to facilitate lengths of straight road overtaking sections along the routes. or in sag curves rather than near crests of curves where it is sometimes difficult for the driver on an up-gradient to appreciate junction layouts to the full. for example. such a junction should operate satisfactorily. although supplementary information in terms of signing and road markings should be used to enhance the message.ROADWAY DESIGN MANUAL 407. from national to arterial or from arterial to secondary route. wherever possible. Provision of a roundabout reasonably close to the turning demand will mitigate this effect. provided that all the necessary sight distances. Version 2. particularly in respect of queue formation. This always adds to the safety of the network by advanced warning.0 Part 2 – Section 400 Page 32 of 33 November 2014 . roundabouts can be used to provide overtaking opportunities in two ways. checks should be made of the effect of the roundabout operation on adjacent junctions. In all cases.  To accentuate the transition from rural to urban or suburban environments. This does not mean that a roundabout cannot be designed on crest curves or are unsafe in such situations. Roundabouts are not recommended along routes which are subjected to Urban Traffic Control Systems unless interaction is limited. It can also be used to mark the separation from gradeseparated roads to at-grade roads. should not be extended to provision of roundabouts where there are no connecting side roads. On single carriageway roads. The lengths of the two lane sections will depend on traffic demand predictions. to the extent that this is possible given the associated traffic predictions. they should be of similar designs for reasons of consistency and hence safety. This use. Table 400.50 kph 1 1 2+ Typical Inscribed Circle Diameter (ICD) 13 . including the following:  Whether the approach roads are single or dual carriageway.  The speed limits on the approach.0 Part 2 – Section 400 Page 33 of 33 November 2014 .40 kph 40 .  The level of non-motorized user flow.03 ROUNDABOUT SELECTION Roundabout type selection is dictated by a combination of many factors.ROADWAY DESIGN MANUAL 407.000 20.46 m 40 . but does not indicate the standard provision for pedestrians.76 m Central island treatment Mountable Raised Raised Typical daily volumes on 4-leg roundabout (veh/day) 0 .20.27 m 27 .  Environmental constraints such as topography and land-take.15.000+ Version 2.10 provides parameters for different roundabout types.000 0 . Table 400.10 COMPARISON OF ROUNDABOUT TYPES AND SELECTION CRITERIA Mini Roundabout Design Element Recommended maximum entry design speed Maximum number of entering lanes per approach Single Lane Roundabout Multi-Lane Roundabout 25 .  The level of traffic flow. This is needed on a site-by-site basis from information gained from existing/predicted pedestrian movements.30 kph 30 . ROADWAY DESIGN MANUAL SECTION 500 : GRADE SEPARATED INTERCHANGES Version 2.0 Part 0 – Divider November 2014 . right-of-way.0 Part 2 – Section 500 Page 1 of 33 November 2014 . traffic composition. 502 INTERCHANGE WARRANTS Interchanges are very costly and should be used only where necessary. terrain. Listed below are features which should be considered during the interchange design process:  Provide consistent design features.  Ramp entrances shall be on the right. Version 2. economics.GRADE SEPARATED INTERCHANGES 501 GENERAL The ability to accommodate high traffic volumes safely and efficiently through intersections depends on how intersecting traffic is handled.  When road-user benefits are substantial. The selection and design of grade separations and interchanges is influenced by roadway classification.  To eliminate a hazardous at-grade intersection.  Where topography does not lend itself to the construction of an intersection. access control. design speed.  To eliminate a traffic bottleneck. so each site should be studied and alternative concepts prepared to determine the appropriate layout. 503 DESIGN CONSIDERATIONS Due to the complex nature of interchange design it is important to establish a set of consistent design parameters.  When making a connection to a freeway. An interchange does this with a combination of ramps and grade separations at the junction of two or more roadways. traffic volume. Interchange types vary widely. improves safety and increases traffic capacity.  Ramp exits shall be from the right. capacity and safety.ROADWAY DESIGN MANUAL SECTION 500 .  For a roadway with access control between selected terminals. Interchanges should be considered based on the following warrants:  Where intersecting traffic volumes are heavy. The greatest efficiency. This reduces or eliminates traffic conflicts. safety and capacity are attained when intersecting through traffic lanes are physically separated. signing requirements.  One exit per direction from main roadway. Crossing conflicts are eliminated by grade separations and turning conflicts are eliminated or minimized depending on the interchange configuration. Heavy traffic volume should be favoured with more direct alignments. Because future expansion is difficult.01 THREE-LEG INTERCHANGES Three-leg interchanges have three intersecting legs. the turning radius is flatter for the heavier left-turning volume and there is less angle of turn for both left turns.  Operation of and type of traffic utilizing interchange. be it high speed rural freeways (DoT) or urban boulevards (ADM).  Choice of grade separation structure. 2011.  Intersecting facility and type of network it serves.  Access control on the interchanges and access ramps need careful consideration so as to avoid queuing and congestion back on to the main service highways.  Costs of chosen interchange ranging from initial construction.01 illustrates several types of three leg interchanges: Version 2. They usually consist of one or more roadway grade separations and one-way roadways for all traffic movements.  Use grades and slopes as flat as possible. for additional examples. three-leg interchanges should only be used when one of the three legs is permanently terminated. 504.0 Part 2 – Section 500 Page 2 of 33 November 2014 .  Consider signing during geometric design. maintenance and vehicle operating costs. and lesser volumes can be looped. See Chapter 10 of AASHTO "A Policy on Geometric Design of Highways and Streets". 504 INTERCHANGE TYPES This section includes examples of commonly used interchange configurations.  Provide ramps for return or complementary traffic movements at same interchange. Skewed crossings are desirable because travel distance is less. Figure 500.ROADWAY DESIGN MANUAL  Ramp design speed beyond exit should preferably be one-half to two-thirds that of the roadway. 01 Three-Leg Interchanges from AASHTO. 2011. Version 2.0 Part 2 – Section 500 Page 3 of 33 November 2014 . “A Policy on Geometric Design of Highways and Streets”.ROADWAY DESIGN MANUAL Figure 500. Typical areas chosen would be at the intersection of scenic areas and a two-lane highway where traffic volumes are low and preservation of the environment takes priority. and interchanges with direct and semi-direct connections. It is adaptable to a wide range of traffic volumes.13 to 500. partial cloverleaves (parclo). Version 2.  High design standard single entrances beyond the structure. Ramps in One Quadrant These varieties of intersection have a role when considering roadways with low traffic volumes. two-lane left turns. Advantages –  High design standard single exits in advance of the structure.02 FOUR-LEG INTERCHANGES Four-leg interchanges include diamond interchanges. and capacity may be increased by widening the ramps and cross road in the intersection area by providing storage lanes. Diamond Interchange Diamond interchanges are the most commonly used interchange (Figure 500. full cloverleaves.02 below. These intersections are chosen on the basis of topography as opposed to volumes and for this reason locations are limited. Initial stages of a more complex interchange use this variety in the early stages.15 inclusive).  Requires relatively little right-of-way. They consist of four ramps which run parallel to the main roadway.ROADWAY DESIGN MANUAL 504. channelization and traffic signals at the ramp cross road intersections. Figure 500.The diamond is used at major/minor roadway crossings with direct high speed exit/entrance ramps on the major roadway and at-grade intersections on the minor roadway.02 Simple Diamond Application . and Figures 500. Each basic interchange type is described and discussed in the following sections.0 Part 2 – Section 500 Page 4 of 33 November 2014 . providing all eight turning movements. Figure 500.ROADWAY DESIGN MANUAL  Comparatively low construction cost.Best suited for areas where right-of-way is restricted.  No need for speed change lanes on or under the structure. Disadvantages –  Overall capacity is limited by ramp intersection capacity.0 Part 2 – Section 500 Page 5 of 33 November 2014 .  Little possibility for future expansion.  Possibility of wrong-way movements. Version 2. All four turning movements are controlled by a single traffic signal and opposing left turns cross to the left of each other.  Turning traffic from the primary roadway is obliged to stop at the minor road.  Single exit feature simplifies primary roadway signing. Single Point Diamond Interchange The Single Point Interchange (SPI) is also known as an urban interchange or a single point diamond interchange (Figure 500.  Increased accident potential unless signalized.  Direct cross road turning manoeuvres. Storage lane treatment may be required.03 Single Point Diamond Interchange Application .03).  No weaving on the primary roadway. Advantages –  Relatively narrow right-of-way.  Capacity is lowered on the minor road due to left turning movements. a painted guidance stripe. and therefore the left turns move at higher speeds.  Adding pedestrian movement to the interchange adds a signal phase and reduces efficiency.  Operates with a single traffic signal reducing delay through the ramp intersection. An interchange with loops in all quadrants is referred to as a "full cloverleaf" and all others as a "partial cloverleaf” (parclo)". Application . at a minimum.0 Part 2 – Section 500 Page 6 of 33 November 2014 .  Higher capacity than a conventional tight diamond interchange.  Not suitable for skewed interchanges.04).  Curve radii for left-turn movements through the intersection are significantly flatter than at conventional intersections.  Extensive retaining walls required where right-of-way is restricted.  Traffic signal is three-phase rather than four.  Handles high volume left-turns on the cross road more efficiently than a diamond.  Vehicle path through the intersection requires.04 Cloverleaf Version 2.Where there is a need to avoid restrictive at-grade left turns and adequate right-ofway is available. Disadvantages –  Higher construction cost than a conventional tight diamond interchange. Figure 500. Cloverleaf The cloverleaf is a four-leg interchange that uses loop ramps to eliminate the four left-turn movements and uses outer ramps for the four right-turn movements (Figure 500.ROADWAY DESIGN MANUAL  Opposing left turns pass to the left of each other.  Lends itself to phased construction.Same as for a basic cloverleaf.05).  Extra travel distance/time required for left turns.  Insufficient deceleration length from primary roadway speed to control speed of inner loop.  Traffic signals are unnecessary.0 Part 2 – Section 500 Page 7 of 33 November 2014 .  Weaving may severely limit capacity.  Double exit on the primary roadway complicates signing.05 Cloverleaf with Collector Distributor Road Application .  Adding weaving lanes on and under the structure increases cost.  Poor safety features. Cloverleaf with Collector Distributor Road A collector distributor road in conjunction with a cloverleaf removes the weaving ramp traffic from the main roadway (Figure 500.  Single structure design. Figure 500.  High weave volumes require collector distributor roads. Disadvantages –  Large right-of-way requirements.ROADWAY DESIGN MANUAL Advantages –  Left-turn conflicts eliminated.  Large trucks may experience problems with tight curves. Version 2. except more suitable for areas with high weaving volumes.  Reduce merging and diverging points on primary roadway.  Signing is more complicated than basic cloverleaf. Application .16 show several parclo arrangements and lists their relative advantages and disadvantages. Partial Cloverleaf (Parclo) A partial cloverleaf is a portion of the full cloverleaf design.  Higher structure costs than basic cloverleaf due to greater span. Ramps should be arranged so that the entrance and exit turning movements create the least impediment to major roadway traffic flows.  Single exit simplifies signing. The general parclo interchange applications.  Weaving eliminated.  Provides a single exit and entrance from primary roadway.  Higher volume than basic cloverleaf design. advantages and disadvantages are given below. Version 2. Figures 500.0 Part 2 – Section 500 Page 8 of 33 November 2014 . General Disadvantages –  Minor road has stop condition for left-turn.This interchange is suitable for locations where by removing two left-turn movements from the intersections.  Can be configured to optimize traffic volume/capacity.  Points of conflict on the minor roadway at the ramp terminals limit capacity and safety.06 to 500.  Future expansion if structure opening wide enough.  Right-turn primary roadway traffic stops at the minor roadway.10 inclusive and 500.ROADWAY DESIGN MANUAL Advantages –  Minimizes weaving conflicts by placing weave on collector distributor road.  Minor road may require left-turn storage.  Expandable if structure opening is wide enough. General Advantages –  Suitable for phased construction. Disadvantages –  May require more right-of-way than basic cloverleaf. the remaining left-turn conflicts can be tolerated.  Minimizes signing difficulties.  Exit terminals in advance of structure. 06 Partial Cloverleaf Specific Advantages –  Entrance ramp loops. Figure 500.0 Part 2 – Section 500 Page 9 of 33 November 2014 . Specific Disadvantages –  Stop condition on minor road and ramps for left turns. Version 2.ROADWAY DESIGN MANUAL Figure 500.  Entrance ramp loops. Specific Disadvantages –  None.07 Partial Cloverleaf Specific Advantages –  Stop for left-turns confined to movements from ramps only. 09 Partial Cloverleaf Specific Advantages –  None.ROADWAY DESIGN MANUAL Figure 500. Version 2. Specific Disadvantages –  Stop condition on minor road and ramps for left turns.  Entrance/exit loops.0 Part 2 – Section 500 Page 10 of 33 November 2014 .  Primary roadway traffic exits on to small radius loop.  Primary roadway traffic exits on to small radius loop. Specific Disadvantages –  Stop condition on minor road and ramps for left turns.08 Partial Cloverleaf Specific Advantages –  None. Figure 500. Semi-direct or direct connections for one or more left-turning movements are often required at major interchanges in urban areas. Directional Interchanges A direct connection is defined as a one-way roadway that does not deviate greatly from the intended direction of travel. Application . even if the minor left turn movements are accommodated on loops. In such cases.11). Free flow is provided for high turning traffic volumes in one or two quadrants. All left-turn connections or only those that accommodate major left-turn movements may be semi-directional in alignment. yet more direct than loops. Specific Disadvantages –  Primary roadway traffic exits on to small radius loop. Directional interchanges have one or more grade separations with direct or semi-direct ramp connections for one or more left turning movements. Interchanges involving two primary roadways nearly always call for directional layouts.0 Part 2 – Section 500 Page 11 of 33 November 2014 . turning movements in one or two quadrants are often comparable in volume to the through movements. Direct connections for one or all left-turn movements would qualify an interchange to be termed directional.  Not conducive to wrong-way movements. the interchange is described as semi-directional. When one or more interchange connections are indirect in alignment. comparable in volume to the through traffic.ROADWAY DESIGN MANUAL Specific Advantages – Figure 500. Interchanges that use direct connections for the major left-turn movements are termed directional interchanges (see Figure 500. Version 2.10 Partial Cloverleaf  Stop condition for left turns confined to movements from minor roadway only. 11 Directional Interchanges Version 2.ROADWAY DESIGN MANUAL Figure 500.0 Part 2 – Section 500 Page 12 of 33 November 2014 . Disadvantages –  High construction costs.  Increased speed and capacity.ROADWAY DESIGN MANUAL Advantages  Reduced travel distance.12 below shows an offset interchange between two primary roadways in close proximity to major buildings or developments.  Require a detailed.12 Offset Interchange via Ramp Highway Advantages  Ramped highway can be located to favour predominant moves within the interchange area.  Higher levels of service. Version 2.  Weaving eliminated.  Require little right-of-way. This particular example shows two trumpet interchanges served by a connecting ramped highway which also serves local service connections via the inclusion of a diamond interchange.  Avoids the indirection in driving on a loop. Figure 500.0 Part 2 – Section 500 Page 13 of 33 November 2014 . time-consuming study Offset Interchanges Figure 500. ROADWAY DESIGN MANUAL Disadvantages –  Substantial out-of-direction travel for 6 out of the 8 turning movements between primary roadways. with less of an emphasis on other ramps. Combination Interchanges Where the analysis or existing surveys show that there is a predominantly high volume of motorists carrying out certain turning movements with respect to other moves. The main movements will shape the interchange.0 Part 2 – Section 500 Page 14 of 33 November 2014 . then an option would be to use a combination of several of the previous interchanges described. Version 2.  Possible confusion to unfamiliar drivers. 0 Part 2 – Section 500 Page 15 of 33 November 2014 .15 Diamond Interchanges with Additional Structures Version 2.14 Diamond Interchanges – Arrangements to Reduce Traffic Conflicts Figure 500.Conventional Arrangements Figure 500.13 Diamond Interchanges .ROADWAY DESIGN MANUAL Figure 500. Exit and Entrance Ramps Version 2.16 Schematic of Partial Cloverleaf Ramp Arrangements.ROADWAY DESIGN MANUAL Figure 500.0 Part 2 – Section 500 Page 16 of 33 November 2014 . capacity. including costs for right-of-way. Once this data has been prepared. construction. Factors such as reduced visibility should be countered by improved overall design. suitability to phased construction. 506 INTERCHANGE DESIGN STANDARDS An interchange consists of the primary through road. the clearances should be increased to obtain the proper sight distance. Version 2. overall adaptability. maintaining traffic during construction. even though it is necessary to increase structure spans or widths. route continuity. preliminary plans. profile.ROADWAY DESIGN MANUAL 505 INTERCHANGE DESIGN PROCEDURES General . to that of the surrounding road network. In general. Spacing . Section 300. ability to sign. aesthetics. Interchange spacing has a pronounced effect on primary roadway operation. speeds and cross section of the intersection should be matched. signing. Gradients that slow down larger vehicles may be substantially more difficult to negotiate in wet conditions and slow moving large vehicles encourage cutting-in from vehicles leaving and entering the highway.In the design of interchanges it is important to provide vertical and horizontal alignment standards which are consistent with the design speed for the roadways and driving conditions expected. Sight Distance . the normal lateral clearance may not provide minimum stopping sight distance because piers. This section deals primarily with the interchange as a whole. it is important that a well functioning. Specific designs for ramps are discussed in the sections that follow. ramps and cross road. the best interchange design concept can be selected. profiles and cost estimates should be prepared. and other appropriate items. Alignment. Sight distance requirements are discussed in Part 2. and highway alignments need to be relatively flat where possible. right-of-way requirements and the effect on the local road network. abutments and bridge rail limit the horizontal sight distance. economic design is conceived.0 Part 2 – Section 500 Page 17 of 33 November 2014 . Decision sight distance shall be provided at exits. route uniformity. where possible. environmental compatibility. signal progression and required lengths of speed change lanes. Design Speed Considerations . If a flatter curve cannot be used. Geometric Cross Sections. For minimum radius curves. From these preferred alternatives. maintenance.Stopping sight distance shall be the minimum sight distance provided on the respective roadways through an interchange and preferably longer. alternative interchange schemes should be analyzed and several preferred alternatives should be selected based on geometry.Minimum interchange spacing is determined by weaving volumes.Since interchanges are expensive and are a vital element of primary roadway capacity. The overriding factors to be considered are those of priority. lane capacity and lane balance issues in urban areas.0 Part 2 – Section 500 Page 18 of 33 November 2014 . residential built-up areas. Uniformity . Even when this principle is satisfied. as decision making lengths and signing become complicated. Coordination of Lane Balance and Basic Number of Lanes . Interchange designs that adhere to route continuity make the driving task simpler by reducing the need for through drivers to change lanes and typically result in simpler signing and improved traffic operations. which should be assigned dependent upon which route handles the highest volume of through traffic. Basic Number of Lanes . such as sudden lane changes and abrupt braking. it is preferable not to have overlapping routes. the overall composition can influence the frequency of errant driver behaviour. the minimum interchange spacing of an urban primary road is 1. This may require consideration of complex weaving. including consideration of basic lanes. lane balance. The basic number of lanes should be established for a substantial length of primary roadway and should not be changed through pairs of interchanges. etc. Consultants should not rely on guide signing alone but should strive for a geometric design that is consistent with route continuity principles. it is desirable for the through route to have at least as many lanes as the route exiting on the right. Furthermore. Route Continuity . However. including shopping areas.Design traffic volumes and a capacity analysis should be used to determine the basic number of roadway lanes and the minimum number of ramp lanes. Signing and Marking .This concept is defined as providing a route on which changing lanes is not necessary to continue on the through route.In some situations. but strategies for providing appropriate route continuity are less defined for complex interchanges. To allow the through route to "maintain its character". leisure and entertainment hubs. all interchanges along a primary roadway should be uniform in terms of geometric layout and general appearance. delineators and other markings should conform to the ADM “Traffic Control Devices Manual” (TCDM).As far as practical. two or more routes share a single roadway within a given corridor. minimum spacing standards are difficult to achieve due to the need for traffic access to various areas of desire. pavement hatching. Overlapping Routes . it is often difficult to construct additional lanes. In a constrained urban setting.ROADWAY DESIGN MANUAL In general.Lane balance and number of lanes are issues which are addressed at the initial planning stages of design and once finalized Version 2. etc. in areas of concentrated urban development. Weaving is a problem which exists on overlapping highways and careful consideration of this is required on shorter sections between successive interchanges. Guidance for route continuity is well documented in the AASHTO “A Policy on Geometric Design of Highways and Streets”. Adhering to the principle of route continuity becomes particularly challenging when the through route carries substantially less traffic than the exiting movement. principles of interchange design can follow. When priority has been established.Signs.5 km. At entrances (to main highway from intersection or merges) – rules typically follow examples like number of lanes beyond merge point X should not be less than number of merging lanes minus 1. truck climbing. where required.0 Part 2 – Section 500 Page 19 of 33 November 2014 . The lane reduction shall be made on the right using a desirable taper rate of 70:1 (minimum taper rate of 50:1). The travelled way of the highway should be reduced by not more than one lane at a time. 3. Plus the number of lanes on the exit minus 1. turning storage. Lane Reduction .  necessary for weaving.The basic number of roadway lanes may be reduced if the exit volume is large enough to change the basic number of lanes required beyond the reduction point for the primary roadway as a whole. Exceptions to the rule exist. Version 2. but may be equal to the sum of merging lanes. the basic numbers of lanes are considered through the interchange area and lane balance is dealt with as follows: 1. turning. Auxiliary Lanes .  local frontage roads do not exist. otherwise design traffic volumes and capacity calculations are rendered useless.  necessary for lane balance. There needs to be continuity in the basic number of lanes and any future variation in traffic demands should be accommodated with auxiliary lanes. An auxiliary lane may be needed when:  Interchanges are closely spaced.  necessary for capacity requirements. 4. Auxiliary lanes may be dropped in a single or two-lane exit or carried to the physical gore nose before tapering into the through roadway. The lane-drop taper should be on a horizontal tangent on the approach side of a crest vertical curve. Auxiliary lanes may be tapered or parallel and shall be a minimum of 3.30m wide. An auxiliary lane may be introduced as a single exclusive lane or in conjunction with a two-lane entrance. Once determined. weaving.ROADWAY DESIGN MANUAL should not be changed through a series of interchanges.  The distance between the end of the taper on the entrance terminal and the beginning of the taper on the exit terminal is short. and other purposes supplementary to through-traffic movement. or on a sag vertical curve. At exits (from main highway to intersection or diverges) – rules typically follow examples like number of lanes beyond diverge point X should be equal to the number of lanes on the highway. speed change. The reduction may be made at a two-lane exit ramp or between interchanges.An auxiliary lane is defined as the portion of the roadway adjoining the travelled way for emergency stopping. 2. but it should not be 20 kph below the main line design speed.  Ramps which connect to two way frontages of roads are commonly accessed incorrectly or the wrong way – channelizing is required. Weaving sections reduce interchange capacity and should be eliminated from the main facility where feasible. The reasons for developing single exits where applicable are:  Transfer the weaving from the main road to the slower road. Collector-Distributor (CD) Roads within Interchanges . The design speed usually ranges from 60-80 kph. They should be analyzed for suitability. but should be given special consideration in order to discourage wrong way movements.  Simplify signing and the decision process. single entrances/exits are developed. Factors contributing are mainly interchange configuration and the exit ramp terminal features in relation to the main road which it interfaces with. but at the minimum they may be one or two lanes width depending on capacity needs and lane balance should be maintained at entry/exits to the mainline. Lack of provision of any one or more of the movements at an interchange can result in wrong way entry.  Provide a high speed exit from the main roadway for all exiting traffic.  Satisfy driver expectancy. Wrong-Way Entry . Version 2. Two-Exit Versus Single-Exit Interchange Design .Incorrect entry on to primary roadways is not a common occurrence.  One way ramps that connect as an un-channelized T-junction may lead to incorrect entry.An example of where this occurs can be found in a full cloverleaf in an urban or suburban area. the single exit design may improve operational efficiency of the entire facility. Refer to the TRB “Highway Capacity Manual” for further discussion on weaving sections. Correct signage benefits the arrangement as far as traffic conflicts are concerned.  Provide decision sight distances for all traffic exiting from the main roadway.In general. Advantages include that weaving is transferred from the main roadway.  Supplying uniformity of exit patterns. These are outlined as follows:  Partial interchanges are the most common susceptible to wrong way entry. Widths should allow for shoulder widths comparable to the mainline to be used to enable barrier erection to discourage indiscriminate crossovers.0 Part 2 – Section 500 Page 20 of 33 November 2014 . single exit interchanges are superior to those with two exits. along with a uniform pattern of exits can be maintained.ROADWAY DESIGN MANUAL Weaving Sections – Weaving sections are roadway segments where vehicles entering and leaving at adjacent access points cross each other’s paths. especially if one of the exits has long ramps. Outer separations between mainline and CD roads should be as wide as practicable but minimum widths are tolerable. by having the exit in advance of the separation structure. Whether used in conjunction with a full or partial cloverleaf. 01 RAMP ENTRANCE / EXIT DESIGN SPEED Main Road Design Speed (kph) Ramp Design Speed (kph) Upper Range (85%) Middle Range (70%) Lower Range (50%) 60 50 40 30 80 70 60 40 100 90 70 50 Source: AASHTO.0 Part 2 – Section 500 Page 21 of 33 November 2014 . Ramps. Downgrades should be limited to 3 or 4% on ramps with sharp horizontal curvature and significant heavy truck or bus traffic. in some cases this is not practical and lower design speeds may be selected.Ideally. However. Profile . Section 10. Ramp grades should be as flat as feasible.9. between vertical curves that connect to the intersection legs. However. Where ramps terminate at grade crossings. but not less than the lower range shown in Table 500. However. ramp design speeds should be selected to match the low-volume running speed on the intersecting roadways.6.ROADWAY DESIGN MANUAL  Unusual or odd arrangements of exit ramps are confusing and lead to wrong way entry. it is desirable that ascending gradients on ramps be limited to: Version 2. General . ramp terminals should be properly transitioned to the intersecting leg. The geometry of the connecting road usually involves curvature and a grade. 2011. “A Policy on Geometric Design of Highways and Streets”.9. Design Speed . the most overriding factor on land adjacent to the intersection is that of providing safe conditions for pedestrians and bicycle users. As a general criterion. Interchanges. design speed choice is not applicable due to the control of the intersection by signals or stop signs. 2011. Profiles at the terminals are largely determined by through-road profiles and are seldom tangent grades. sight distance is more important than a specific gradient control and should be favoured in design. for more details refer to AASHTO “A Policy on Geometric Design of Highways and Streets”. etc. The above speeds apply to the controlling ramp curve.01 below: Table 500. and in particular Section 10. 507 RAMP DESIGN STANDARDS This section includes general guidance on ramp design standards. However.A typical ramp profile consists of a connecting road on an appreciable grade. In urban areas.A ramp is typically a one-way roadway connecting interchange legs and consists of a terminal at each leg and a connecting road. The minimum sight distance provided anywhere along the ramp shall be the stopping sight distance. Shoulder Width .0 Part 2 – Section 500 Page 22 of 33 November 2014 .0m.17. Geometric Design Standards. or the combination of profile and cross slope. Profile grade considerations are of particular concern through entrance and exit gore areas. street lights and roadway structure supports shall be kept out of the graded gore area.The factors and assumptions of minimum-turning roadway curves for various speeds apply to ramps and are discussed in Part 2 . In some instances the ramp profile.Section 300. the algebraic difference in pavement cross slope shall not exceed 5%. The gore nose is defined as the point where the distance measured between the main line and ramp travelled ways is 7.02 RAMP GRADES Ramp Design Speed (kph) Ramp Gradient (%) 70 . Heavy sign supports. Where adjacent lanes or lanes and gore areas at primary roadway entrances and exits are not in the same plane. Gores . Sight Distance . the unpaved area beyond the nose should be graded level with the roadways.Section 200. If feasible.80 3-5 60 4-6 40 . Refer to the section on entrance/exit ramp and ramp terminals for specific requirements at those areas.The term "gore" indicates an area downstream from the shoulder intersection points as illustrated in Figure 500. Geometric Cross Sections.ROADWAY DESIGN MANUAL Table 500.50 5-7 30 . Version 2. is sufficiently different from the roadway through lanes that grade breaks across the gore become necessary.40 6-8 Curvature .Shoulder widths for ramps shall be as indicated in Part 2 . Typically the ramp lane reduction shall be made using a desirable taper rate of 70:1.05. also apply to ramps. Lane Additions – Lane additions to ramps shall use a taper rate of 10:1. 50:1 maximum.04 and 200.0 Part 2 – Section 500 Page 23 of 33 November 2014 . the curve radius should be increased to reduce the required standard superelevation rate.ROADWAY DESIGN MANUAL Figure 500. Geometric Design Standards. Superelevation and Cross Slope . with a central angle greater than 60º. the lane furthest to the right of the ramp shall be widened in accordance with Table 500. 2011 Lane Drops .17 Typical Gore Area from AASHTO.03 in order to accommodate large truck wheel paths. Lane drop tapers should not extend beyond the 2. Both the edge of travelled way and the edge of shoulder should be examined at ramp junctions to assure a smooth transition. More than one lane may be widened if warranted by truck and bus usage. “A Policy on Geometric Design of Highways and Streets”.0m point (the beginning of the weaving length) without the provision of an auxiliary lane. Ramp superelevation rates shall be as per Tables 200.Section 200. Where feasible. Widening .The factors controlling superelevation rates discussed previously in Part 2 . Version 2.When ramps have curve radii of 90m or less. 0 > 90 0 3. Increasing the radii beyond 60m is typically not cost effective as the slight increase in design speed is usually outweighed by the increased right-of-way requirements and the increased travel distance.5 65 . To enable safe weaving distances along with a safe distance for say sign locations. Consideration should be given to providing a directional ramp when loop volumes exceed 1. Version 2. loop ramps are one lane unless capacity warrants additional lanes. Table 200.0 4. For roadway design speeds greater than 80 kph. On loop entrance ramps this can often be facilitated by beginning the ramp with a short tangent (20m to 30m) that diverges from the cross street at an angle of 4º to 9º.0 45 .0 6. If multiple lanes are provided.Normally.0 Part 2 – Section 500 Page 24 of 33 November 2014 .85 55 .90 0. normally only the right lane needs to be widened. a reasonable distance is required between successive ramp terminals. Extremely tight curves (less than 35m radii) should be avoided because they lead to increased swept path curvature and increase the potential for vehicles to enter the curve with excessive speed.3 4. the loop design speed should not be less than 40 kph (45m radius). Exit (EX) : Exit (EX). This spacing is wholly dependent on several factors which range from weaving lengths to interchange type and class of the following ramps: 1. it is important to develop the standard two-thirds of full superelevation rate by the beginning of the curve.65 Note: For ramps having curve radii of 90m or less with a central angle 0 greater than 60 .25 75 . See Part 2. Loop Ramps . Distance between Successive Ramp Terminals . either due to inadequate deceleration on exit ramps or due to driver efforts to maintain speed on entrance ramps to facilitate acceleration and merging.06 for further guidelines on radius versus speed limit.55 1.500 vehicles per hour. Ramp Radius Widening Lane .03 RAMP WIDENING FOR TRUCKS Ramp Radius (m) Widening (m) Lane Width (m) < 45 2. Where the loop ramp has a small radius on a steep descent (over 6%). several ramp terminals are often located in succession in relative close proximity.65 1.When considering urban primary roadways.ROADWAY DESIGN MANUAL Table 500. Section 200.2 4.75 0.6 4. Research indicates that trucks often enter loops with excessive speed. Longer tangents are desirable.Radii for loop ramps should normally range from 45m to 60m. Other considerations should include such variables as grade and profile Version 2. Passing sight distance is not needed.04 below for details. Entrance : Exit (Weaving). 3.ROADWAY DESIGN MANUAL 2.0 Part 2 – Section 500 Page 25 of 33 November 2014 .Decision sight distance is desirable along the primary roadway prior to an exit nose and the entire exit terminal should be visible. Sight Distances on a ramp should be at least as great as the Design Stopping Sight Distance. Exit : Entrance. Table 500. All primary roadway entrances and exits shall connect to the right of through traffic. tapers and islands. See Table 500. There should be a clear view of the entire end terminal including exit nosing. Entrance (EN) : Entrance (EN). 4. 5.The ramp entrance/exit is that ramp portion adjacent to the through travelled way. including speed-change lanes. Turning Roadways.04 RECOMMENDED MINIMUM RAMP TERMINAL SPACING EN-EN or EX-EX EX-EN Turning Roadways EN-EX (Weaving) *Not applicable to cloverleaf loop ramps Full Freeway CDR or FDR Full Freeway CDR or FDR System Service Interchange Interchange System to Service Interchange Service to Service Interchange Full Freeway Full Freeway CDR or FDR 480m 300m CDR or FDR Minimum Lengths Measured between Successive Ramp Terminals 300m 240m 150m Notes: FDR = Freeway Distributor Road CDR = Collector Distributor Road 508 120m 240m 180m 600m 480m EN = Entrance EX = Exit ENTRANCE / EXIT RAMP DESIGN STANDARDS General . Entrance/Exit Sight Distance . The following paragraphs discuss various design elements of ramp entrances/exits. The sight distance on a freeway preceding the approach nose of an exit ramp should exceed the minimum stopping sight distance for the through traffic design speed by a desirable 25% or more. The design speed at the nose should be consistent with approach alignment standards. cross slopes and gore layout and design.19 and 500. The minimum deceleration length shown on Figure 500.20 for single lane.The minimum design speed at the exit nose should be 80 kph or greater for both ramps and branch connections.18.0 Part 2 – Section 500 Page 26 of 33 November 2014 . Ideally ramp design speeds should always match that of the low-volume running speed of the intersecting highways. When an exit must be located where visibility is limited by physical restrictions. When the subsequent curve is a descending loop or hook ramp. Exit Design Speed . If the approach is a branch connection or diamond ramp with high alignment standards. The minimum length of auxiliary lane shall be 300m desirable (180m minimum). Parallel Type Entrance . A branch connection is defined as a multi-lane connection between two primary roadways. vertical curvature and superelevation. an auxiliary lane in advance of the exit should be provided.18 shall be provided prior to the first curve beyond the exit nose.ROADWAY DESIGN MANUAL design.A parallel entrance gives an extra length of acceleration to merge with the main highway as well as in some instances providing additional storage which aids through flow traffic on the mainline. 500. or if the upstream condition is a sustained downgrade. two lane entrances and exits. the minimum design speed should be 80 kph. and diverging branch connections respectively. Version 2. Entrance Design Speed . deceleration length should be increased. which cannot be corrected by cut widening or object removal. Entrance/Exit Designs . Decision sight distance should be provided at primary roadway exits and branch connectors.Design of freeway entrances and exits should conform to the standard designs in Figures 500. This provides for adequate deceleration before entering the curve. 2006 Version 2.18 Single Lane Freeway Entrances and Exits from Caltrans “Highway Design Manual”.ROADWAY DESIGN MANUAL Figure 500.0 Part 2 – Section 500 Page 27 of 33 November 2014 . 2006 Version 2.ROADWAY DESIGN MANUAL Figure 500.0 Part 2 – Section 500 Page 28 of 33 November 2014 .19 Two-Lane Entrance and Exit Ramps from Caltrans “Highway Design Manual”. 2006 Version 2.0 Part 2 – Section 500 Page 29 of 33 November 2014 .ROADWAY DESIGN MANUAL Figure 500.20 Diverging Branch Connections from Caltrans “Highway Design Manual”. This design may be utilized in situations where the estimated design year volume exceeds 1500 equivalent passenger cars per hour.The lane drop taper on a freeway-to-freeway connector shall not be less than 70:1. For diverging connections where less than capacity conditions beyond the design year are anticipated.18 for ramps. except where it does not appear that capacity on the primary roadway will be reached until five or more years after the 20 year design period. In this case the length of auxiliary lane should be a minimum of 300m.19.19 includes a minimum 300m auxiliary lane parallel to the roadway.20. Two-Lane Exit Ramps – Where design year estimated volumes exceed 1.A standard two lane entrance ramp is illustrated in Figure 500.A branch connection should be provided when the design year volume exceeds 1500 equivalent passenger cars per hour. but utilizing the flatter diverge angle shown in Figure 500. Diverging branch connections should be designed as shown in Figure 500.18. At a branch merge. To satisfy lane-balance needs. a one-lane width exit ramp should be provided with provision for adding an auxiliary lane and an additional lane on the ramp. which is only used where adequate design year capacity exists on the through facility.500 but more than 900.2-lane entrances are warranted for two situations.20.500 equivalent passenger cars per hour. an 800m length of auxiliary lane should be provided beyond the merge of one lane of the inlet. Merging branch connections should be designed as shown in Figure 500. The standard ramp exit connects to a local street.Freeway-to-freeway connectors may be single lane or multi-lane. the length of auxiliary lane in advance of the exit should be 400m. Two-Lane Entrance Ramps .ROADWAY DESIGN MANUAL Single-lane Freeway to Freeway Connections .0 Part 2 – Section 500 Page 30 of 33 November 2014 .19 should be used. If capacity is inadequate. at least one additional lane should be provided downstream. either as branch connections or because of capacity needs for the on-ramp. Single lane loop connectors may use a diverge angle of as much as that shown on Figure 500. consideration should be given to extending the auxiliary Version 2. Where design year volume is between 900 and 1.500 equivalent passenger cars per hour. initial construction should provide a single lane connection with the capability of adding an additional lane. Branch Connections . Single-lane connectors in excess of 300m in length should be widened to two lanes to provide for passing manoeuvres. Single lane directional connectors should be designed using the general configurations shown on Figure 500.19. Provisions should also be made for widening to three or more lanes at the cross road intersection. Branch Lane Drops . For volumes less than 1. if necessary. The diverging branch connection connects to another primary roadway and has a flatter angle that allows a higher departure speed. A minimum 400m auxiliary lane should be provided in advance of a two-lane exit. Figure 500. Two-Lane Entrance Ramps . a 2-lane exit as per Figure 500. The choice will depend upon interchange configuration and driver expectancy. Vertical curves located just beyond the exit nose should be designed with a minimum 80 kph stopping sight distance. Where it is necessary to locate entrances/exits on a curve. Exit Profiles . 2006 On curved entrance ramps.Entrance profiles should approximately parallel the roadway profile for at least 30m prior to the inlet nose to provide inter-visibility in merging situations. The vertical curve at the inlet nose should be consistent with approach alignment standards. it is recommended that multiple ramp lanes taper to a single lane prior to the 2m separation point (where merging is considered to begin).25m point) to the end of the acceleration lane taper should equal the sum of the distances shown on Figure 500. Entrance/Exit Grades . the ramp entrances and exit tapers should also be curved.18. “Highway Design Manual “. The exit taper radius should approximate the roadway edge of travelled way in order to develop the standard degree of divergence (Figure 500. Beyond this point. a minimum 450m long auxiliary lane should be provided to Version 2.0 Part 2 – Section 500 Page 31 of 33 November 2014 . The 50:1 taper may be curved to fit the conditions. the distance from the inlet nose (4. and the 1. progressively lower design speeds may be used to accommodate loop ramps and other geometric features.21 Curved Entrance/Exit Locations from Caltrans. This provides maximum sight distance and optimum traffic operation. Figure 500.ROADWAY DESIGN MANUAL lane to the next interchange or adding additional roadway through lanes. Entrance Profiles .000m radius curve may be adjusted. For most urban situations. Ramp profile grades should not exceed 6%.Grades for primary roadway entrances and exits are controlled primarily by sight distance requirements. Entrance/Exit Locations – Primary roadway entrances and exits should be located on tangent sections wherever possible. Where large-truck volumes exceed 20 vehicles per hour on ascending entrance ramps with sustained upgrades exceeding 2%.21). Sight distances on entrance terminals need to be maximized in order for motorists to choose an acceptable gap to merge. Exit Ramp Transitions .Factors which influence the location of ramp terminals include sight distance. based on near-minimum turning conditions. in certain instances. have ramps that are located beyond the structure and the designs are explained further in Section 10. of AASHTO “A Policy on Geometric Design of Highways and Streets”. It is normally expected by the motorist to exit in advance of the separation structure and exits which are concealed by such things as vertical curves should be avoided.5. right-of-way costs.Exit ramps in urban areas may require additional lanes at the cross road intersection to provide storage and increase capacity.Section 400.Ramp terminals should be treated as at-grade intersections.Shoulders should be provided on ramps and terminals on interchange areas to provide emergency vehicle stopping beyond travelled ways. When this is the case. vertical kerbs with sidewalks are to be used. 509 RAMP TERMINAL DESIGN Terminals . Ramps at interchanges should be designed without kerbs. Ramp terminals should connect where the grade of the over crossing is 4% or less to avoid potential overturning of trucks. and the proximity of other local road intersections. Version 2.ROADWAY DESIGN MANUAL ensure satisfactory separating conditions. an additional lane should be provided on the ramp to permit passing manoeuvres. Where pedestrian protection is required. these should be located on downward gradients to aid truck acceleration when merging with high speed main traffic. General Design Consdierations.Ascending off-ramps should join the cross roads on a reasonably flat grade to expedite truck starts from a stopped condition. Loop ramps. If the length of a single lane ramp exceeds 300m. crossroads gradient at ramp intersections. 2011. On low speed areas. Kerbs are only required at areas of particularly difficult drainage as needed in urban areas. Terminal Locations . construction costs. The terminal design shall be in accordance with Part 2 .9. Terminal Location Sight Distance . kerbs may be placed at the roadway edge. In the example of high speed entrance ramp terminals.Certain interchange arrangements dictate that ramps intersect the crossroads at-grade (diamond and partial cloverleaf). This intersection should be placed at an adequate sight distance from the separation structure to enable adequate sight distances for all approaches. Terminal Grades . circuitry of travel for left-turn movements. kerbs are laid on terminals near road merge and omitted in central ramp portions. Shoulders and Kerbs . At Grade Intersections. storage requirements for left-turn movements off the crossroads.0 Part 2 – Section 500 Page 32 of 33 November 2014 . 0 Part 2 – Section 500 Page 33 of 33 November 2014 . Where ramp set back is unobtainable. Figure 500.22 illustrates ramp setback from an over crossing structure.ROADWAY DESIGN MANUAL Where a separate right turn lane is provided at ramp terminals the turn lane should not continue as a "free" right unless pedestrian volumes are low. the right turn lane continues as a separate full width lane for at least 60m prior to merging. Sight distance is measured between the centre of the outside lane approaching the ramp and the eye of the driver.Horizontal sight restrictions may be caused by bridge railings.22 Location of Ramp Intersections on the Crossroads/Setback Version 2. bridge piers or slopes. but the same relationship exists for sight distance controlled by piers or slopes. with the ramp vehicle assumed to be 3. sight distance shall be provided by flaring the end of the overcrossing structures or setting back the piers or end slopes of the undercrossing structures.0m back from the edge of the shoulder at the crossroads. Figure 500. Terminal Sight Distances . This figure is based on sight distance being controlled by the bridge rail. Provision of the "free" right should also be precluded if left turn movements are allowed within 125m of the ramp intersection. and access control is maintained for at least 60m past the ramp intersection. 0 Part 0 – Divider November 2014 .ROADWAY DESIGN MANUAL SECTION 600 : STRUCTURAL PAVEMENT DESIGN Version 2. 02 DESIGN REQUIREMENTS As AASHTO has shifted from the Empirical to Mechanistic-Empirical design approach.  Asphalt material details. in conjunction with the DoT for Abu Dhabi City roads and highways.  Validation of input design parameters. characterized by Version 2.0 Part 2 – Section 600 Page 1 of 23 November 2014 . Consultants in the interim shall also take into consideration the latest edition (with interim revisions) of the “Sustainability Guideline for ADM.01 GENERAL Pavement design shall be carried out during the Preliminary Design Phase. However. It should be noted that at the time of issuance of this revised document. 602 STRUCTURAL PAVEMENT SECTION DESIGN 602. the proposed design reference standards to be adopted shall be reviewed. discussed and agreed with the ADM Pavement Design Reviewer in advance. In situations where existing pavements are considered in pavement design. implementing both the Empirical and Mechanistic-Empirical approaches of design. This is being based on the latest version of the AASHTO MechanisticEmpirical Pavement Design Guidelines and Australian Pavement Design Guidelines “Austroad2009”. This will be used to recommend the required actions to be taken to ensure proper utilization of the existing asphalt pavement during the expected project service life. until these new guidelines are issued to consultants. considering the following in addition to current design requirements and considerations:  Incorporation of the latest design technologies. The Consultant should evaluate causes of distress in existing road pavements. ADM is currently working on the preparation of the Updated Pavement Design Procedure. IRI Employees and Consultants 2010”. Unified Pavement Design Guidelines were being prepared by the ADM.  Regional materials and climate factors.  Traffic movement studies (truck factors). a full pavement condition evaluation is required to assess the current pavement condition and estimate the residual life. 602.ROADWAY DESIGN MANUAL SECTION 600 – STRUCTURAL PAVEMENT DESIGN 601 INTRODUCTION This section outlines the pavement design procedure to be followed.  Lessen pavement distress. and establish the pavement condition index. W18 Traffic is represented in the AASHTO “Guide for Design of Pavement Structures” method by the equivalent single axle load (ESAL). water and energy consumption. Several pavement design options should be studied and optimized in value engineering terms (technically.03 PAVEMENT DESIGN METHOD .  Increase savings in raw materials. To estimate the total number of vehicles utilizing a pavement during its design life. severity and distribution area. To determine the total number of vehicles. financially and environmentally) and the following sustainability criteria should be considered:  Maximize service life. To calculate this value.0 Part 2 – Section 600 Page 2 of 23 November 2014 .  Simplify and adopt more sustainable maintenance activities. The second component. the number of vehicles in certain weight classifications derives from detailed counts of vehicle types in the traffic mix at a variety of times and places within each Version 2.  Recycled materials (concrete aggregates and pavement recycling). or the number of 18-kip equivalent single axle loads that will pass over the pavement during its initial service lifetime (typically 20 years). calculate the average rate between the existing traffic volume and the traffic volume in the design year. That average rate is then multiplied by the projected design life of the pavement. three components are required: 1.  Minimize overall life-cycle cost. Examples include geo-synthetics (which are detailed in Section 702. the breakdown of those vehicles by weight classification.  Improve road constructability. For existing pavement studies. the number of vehicles would be estimated using the design period. detailed within the Standard Specifications. use a straight line interpolation between the existing traffic volumes and traffic volumes in the design year.ROADWAY DESIGN MANUAL distress type. For new pavements.EMPIRICAL Step 1: Develop Equivalent Single Axle Load. and 2.  Use of state-of-the-art technologies and new materials to achieve more sustainable pavement designs. existing and projected traffic volumes are needed.06) and asphalt mix (polymer modified) additives. and  Consideration of use of soil improvements to deal with in-situ problematic soils. a means of converting the number of vehicles in each class to an 18-kip equivalent single axle load. the number of vehicles which will pass over the pavement during its lifetime. and 3. 602. For a simplified approach. information which would be even harder to come by than the traffic counts.01 form an acceptable interim approach: Table 600.  most other methods require very detailed information about tire pressures. detailed weight and composition data can be obtained to allow the development of system-specific truck equivalency and tire correction factors. and  the equivalency factors can be easily and directly incorporated within the method. broken down by vehicle class. the AASHTO correlation should be used. and the pavement thickness.0 Part 2 – Section 600 Page 3 of 23 November 2014 . Unless site specific investigations determine different resilient modulus-CBR correlation factors. It should be noted that these tables do not reflect the higher tyre pressures that are often used in ADM. the type of vehicle. the tabulated values still form a good starting place for equivalency factors. See the AASHTO Pavement Design Guidelines for a complete set of tables.01 GENERIC EQUIVALENCY FACTORS Vehicle Type Equivalency Factor Heavy Truck 6. wheel configurations. the values in Table 600. Step 2: Develop Soil Resilient Modulus. the overall 18-kip equivalent single axle loading can be estimated. to the 18-kip equivalent single axle load is needed. The axle load equivalency factors used in the design method vary with the load on the axle. but the AASHTO factors can be used in the empirical design methodology.500 x CBR Version 2.5 Medium Truck 1. The AASHTO correlation below gives reasonable agreement between the California Bearing Ratio (CBR) and the soil resilient modulus. or with very detailed traffic counts. Finally. However. MR The resilient modulus of the soil subgrade is required for design and must be measured or estimated.0008 Using these values and counts or estimations of traffic loading within the classifications.25 Automobile 0. Ideally. and load layouts. a means of converting the rough traffic numbers. The advantages of the AASHTO equivalency factor approach outlined above are that:  the method can be used with very little data about the traffic composition.0 Light Truck 0.ROADWAY DESIGN MANUAL roadway class. unless project specified by the ADM. CBR value ≤10% MR = 1. 64 where: MR = Resilient Modulus (psi) CBR = California Bearing Ratio Step 3: Determine the Overall Standard Deviation.090 Main Road 99. So The overall standard deviation is a dimensionless parameter that accounts for random variation in the traffic projections and normal variation in the pavement parameters.645 Roadway Classification Step 5: Select Design Serviceability Loss. and so describes the amount Version 2.0 Part 2 – Section 600 Page 4 of 23 November 2014 . and represents a quantification of subjective impressions about the roadway quality.02 RELIABILITY PARAMETERS Level of Reliability R Standard Normal Deviate. other factors being equal. Table 600.02 contains recommended values for the roadway classifications. The level of reliability is represented in the AASHTO equation by the standard normal deviate.45 for So is commonly used for flexible pavement materials. rutting. Z R. Simply put.9 -3.ROADWAY DESIGN MANUAL CBR value >10% MR = 2. ZR Truck Route 99. The design serviceability loss (ΔPSI) is the allowable change from the initial serviceability (po) to the terminal serviceability at the end of the design period (pt).9 -3. the thicker the pavement section the higher the likelihood that the pavement will last throughout its intended service life. A value of 0. and provides no information about the failure mode (e. Table 600. stripping.9 -3. low maintenance management mode. The design serviceability loss is obtained by simply subtracting the final value from the initial value. Note that a low serviceability implies only that the road has become difficult to travel over.090 Rural/Urban 99. cracking) that has created the low serviceability.555 x CBR0.g.327 Sector Road 95.0 -1. Serviceability ranges from 0 (impassable) to 5 (ideal). Step 4: Select the Level of Reliability.0 -2. Statistically. it provides a means of accounting for areas of weaker than average pavement receiving higher than expected traffic. R The level of reliability describes the degree of certainty that the pavement will last as long as the design service period.090 Expressway 99. and in the design nomograph by R. PSI The pavement serviceability is a general measure of the pavement’s ability to service the traffic which must pass over it. The table contains very conservative values to reflect the need for high performing pavements in a high-growth. Step 1 = Soil Resilient Modulus (psi). ΔPSI Truck Route 4.2 3.03 SERVICEABILITY PARAMETERS Roadway Classification Initial po Terminal pt Design Serviceability Loss. However.20 + 2. Step 2 = Overall Standard Deviation.0 1.2 – 1. the structural number is used to determine the thickness of each pavement material layer using the appropriate material coefficients from Table 600.0 Part 2 – Section 600 Page 5 of 23 November 2014 .0 1.04.03.2 Expressway 4. The structural number can be solved using the equation below.19) Where: W18 MR So = Equivalent Single Axle Load (ESAL). which is a trial-and-error procedure. log10 .0 1.07 + log10 (ΔPSI / (4.5 Sector Road 4. Step 3 ZR = Standard Normal Deviate. SN The preceding steps 1-5 are independent.2 Freeway 4.6 1.36 x log10 (SN+1) – 0.ROADWAY DESIGN MANUAL of degradation of service which is acceptable during the design lifetime. Step 7: Determine Pavement and Base Thickness Once SN is determined from Step 6 and after review and coordination with the geometrical design.2 Main Road 4.6 Step 6: Solve for the Structural Number.2 3.2 3. Step 5 SN = Structural Number.W 18 = (ZR) x (So) + 9. Version 2.0 2.32 x log10MR – 8.4 1. Recommended values for the different roadway classifications are shown in Table 600. Step 6 or the solution may be obtained by using the nomograph in Figure 600. Step 4 ΔPSI = Design Serviceability Loss.01.1 2. a value must be obtained for each one in order to complete Step 6.5)) 0. Table 600.4 + (1094 / (SN+1)5. 05 Soil Subbase 0. For base or sub-base layers which do drain. consultation is required with the ADM reviewer for selection of the appropriate drainage coefficient value. Notes to Table 600. and finally using MR of subgrade soil to achieve the minimum required road sub-base thickness. The use of recycled materials is encouraged within all pavement material layers. SN = Structural Number desired for the pavement section (Step 6).04 PAVEMENT MATERIAL COEFFICIENTS Pavement Material Coefficient.tn where: ai = Material coefficient for each material in the pavement section (Table 600.17 Aggregate Base 0. ti = Thickness of each material in the pavement section (cm). specifically material design recycled product material characteristic properties and quality control and quality assurance procedures for materials containing recycled products.04 The structural number is related to the material coefficients and thicknesses as follows: SN = a1.04.04). c) Layer Design Analysis Layered design analysis shall be undertaken to determine the thickness of each layer in accordance with the “AASHTO Guide for Design of Pavement Structures”.t2 + … + an. ai (per cm) Asphaltic Concrete 0. will be required to be validated by the Consultant.0 for Abu Dhabi and have been excluded from the equation. b) Material / Layer Coefficients The designer may propose material/layer coefficients as alternatives to those detailed in Table 600.t1 + a2. These shall be agreed and approved with the ADM reviewer after validation before incorporation into any layer thickness calculation and layer design analysis. Conformance with the Roadway Design Manual and Standard Specifications. then using MR of road sub-base to determine the minimum required road base course thickness. This shall be reported in full to the ADM reviewer within the Pavement Design Report.04: a) Drainage Coefficients The drainage coefficients are assumed to be 1. Version 2. This may be achieved by starting with MR of the road base course to obtain the minimum required asphalt thickness.ROADWAY DESIGN MANUAL Table 600.0 Part 2 – Section 600 Page 6 of 23 November 2014 . waterproofing system and associated protection. the combination and thickness of the individual pavement material sections is based on such factors as aggregate availability. These factors are discussed in more detail below: Material Availability . This is assuming that the existing pavements are satisfactory. etc. Consideration should also be given to maintenance cost. Continuity of Pavement Type .Comparative costs provided in the pavement design procedure should be given consideration in the selection of the pavement design.Conservation of natural resources should be given consideration in the evaluation of the pavement design.0 Part 2 – Section 600 Page 7 of 23 November 2014 . poor drainage. flooding. restrictions on overall thickness and number of lifts required. The use of sand-asphalt for this purpose is not recommended. cost of various pavement materials. An example of the Flexible Pavement Structural Design is provided in the following pages.Consideration should also be given to the feasibility of the proposed design with regards to standard construction methods. there are situations when local conditions. Any resurfacing of the wearing course over bridges will be carried out by milling the existing material and reinstating new asphalt to the same level prior to maintenance. consideration should be given to continuing the same type of existing pavements. Anticipated Construction Problems . Once the structural requirements are met. Past experience and judgment should be used in the final selection of the pavement design. Variations in the total surfacing thickness over bridges should be accommodated in the upper layers.ROADWAY DESIGN MANUAL Various combinations of pavement materials of various thickness are possible to meet or exceed a given structural number. Note that there is no requirement to allow for future overlays. Location and Local Conditions . minimum recommended thickness. Layers of asphaltic wearing course will be of uniform thickness of not less than 45mm. aggregate size. Costs . if any.Although there are many pavement designs that will meet the requirements of the design equation. Tunnels Road surfacing associated with bridges and tunnels shall not exceed 110mm in thickness. Version 2. An additional protective layer (APL) should only be used when required by the specific waterproofing system proposed.To maintain uniform driving conditions. Availability of suitable materials should be investigated in the vicinity of the project. where one design might function more efficiently than another.. especially if a new project is relatively short. such as underground utilities close to the surface. Where there is no APL. the asphalt directly overlaying the waterproofing system should have a design air void content of no more than 4%. which includes road pavement layers. Paving of Bridges. 502. determine the pavement materials and thickness required for a truck route. The pavement design will then be carried out as follows:  Calculate required Structural Number.756 Vehicle Split Table 600. leaving the existing HMA. Steps 1-6 for Flexible Pavement Design  Identify desired material(s) and required depth(s) to meet SN through iterative process Step 7.182 W18 = 131. W18 Table 600.138 5% Light Truck 0.5 110. MR (CBR ≤ 10%) MR = 1. Step 1 .01 Generic Equivalency Factors W18 5% Heavy Truck 6.925.013.Develop Soil Resilient Modulus.FLEXIBLE PAVEMENT STRUCTURAL DESIGN Given the vehicles per lifetime and the vehicle split. Recycle and Overlay.Determine the Overall Standard Deviation.500 x 10 = 15.0 Part 2 – Section 600 Page 8 of 23 November 2014 .396 5% Medium Truck 1. Mill and Overlay. a) The age and condition of existing underlying materials must be taken into consideration when assigning material/layer coefficients.0008 230.500 x CBR = 1.400.45 typical Version 2.000 Step 2 . Pavement Rehabilitation will typically involve the HMA surface only. A Pavement Condition Evaluation Report shall be undertaken and reported to the ADM reviewer. b) Layer coefficients for the existing layers shall be agreed with the ADM reviewer along with any adjustment to the design period required.25 4.05 EQUIVALENT SINGLE AXLE LOAD CALCULATION Vehicles per Lifetime 338. EXAMPLE .0 16.000 psi Step 3 . So So = 0. sub-base and subgrade in place.231.Develop Equivalent Single Axle Load.284 85% Automobile 0.ROADWAY DESIGN MANUAL Rehabilitation of Flexible Pavement – Pavement Condition Evaluation Method: Hot Mix Asphalt (HMA) Overlay. 0 Step 7 .2 .Determine Material Thickness Table 600.04 45 1. R Truck Route. ΔPSI = 1.17 30 5.2 Step 6 .0 . SN SN = 8.0 Part 2 – Section 600 Page 9 of 23 November 2014 .03 : po = 4. ΔPSI Table 600.02 : R = 99.Solve for Structural Number.05 22 1.0 Note: Various material combinations can be compared economically to determine the optimum design.8 Actual SN = 8. ZR = -3. pt = 3.06 MATERIAL THICKNESS CALCULATION Pavement Material Coefficient (per cm) Trial Thickness (per cm) SN Contribution Asphaltic Concrete 0.9 .ROADWAY DESIGN MANUAL Step 4 .Select the Level of Reliability. Version 2.1 Aggregate Base 0.Select Design Serviceability Loss. Table 600.090 Step 5 .1 Soil Subbase 0. 01 Design Chart for Flexible Pavements based on using Mean Values for each Input Version 2.0 Part 2 – Section 600 Page 10 of 23 November 2014 .ROADWAY DESIGN MANUAL Figure 600.  MR value of pavement layer materials.).  Skid Number.  Drainage factor of granular base course and sub-base layer.  Road hierarchy of roads included in project scope.  Water table condition and concerned recommendations of geotechnical study. scope. according to road hierarchy:  Reliability (R). 4) Design Geotechnical Data The following geotechnical data is considered as a minimum requirement for pavement design purposes.  Land use of project and adjacent areas.04 PAVEMENT DESIGN REPORT A Pavement Design Report should be compiled for submission and approval of ADM. objective. etc.0 Part 2 – Section 600 Page 11 of 23 November 2014 .  Standard Deviation (So). 5) Pavement Layer Material Properties  MR value of supporting soil. Texture Level and Aggregate Properties.  Geotechnical study recommendations that will be adopted in pavement design (if any). area.  Selected value of soil CBR.  Standard Normal Deviate (ZR).  Soil MR value and method of MR calculation. Further testing and geo-physical/geotechnical requirements that may be required by the ADM Geotechnical Specialist to fulfill the geo-physical/geotechnical viewpoint should be fulfilled by the consultant.  Layer coefficient (ai) for different pavement layers. Version 2. The contents of this report will as a minimum include the following: 1) Introduction  Project information (location.ROADWAY DESIGN MANUAL 602.  Summary of approved project Geotechnical Report results. 2) Reference Standards of Pavement Design 3) Pavement Design Parameters Selected values of the following.  Pavement structure details for all types of pavement. etc. 7) Pavement Design Calculations  Calculation of SN for each pavement layer.  Land use plan (for different land uses within project area). 9) Appendices Appendix A – General  Project location map.  Selected pavement layer thicknesses for different design options in the project. 8) Recommendations  Recommended pavement section(s). including tie–ins.  Construction details.  Calculated Average Daily Traffic (ADT). widening. connection details for different Part 2 – Section 600 Page 12 of 23 November 2014 .0  Plan showing different pavement types.  Traffic growth factor for pavement design life.  Road hierarchy plan. Directional Distribution Factor (Dd).  Connecting pavement layers with construction specifications. showing the basis of selection. and Lane Distribution Factor (Ld).  Calculation of predicted number of ESALs equivalent single axle load W 18. Appendix B – Pavement Design Drawings Version 2.  Truck factor for different types of traffic vehicles.  Traffic classification percentage of different traffic vehicle types utilizing the project area.  Selected peak hour traffic volume.ROADWAY DESIGN MANUAL 6) Design Traffic Data The traffic study is to be in accordance with the requirements of the ADM Traffic Specialist and shall include as a minimum:  Summary of approved traffic study results.  Selected traffic parameters.  Calculation of pavement layer thickness design options. the consultant is required to submit the project pavement design data in GIS format.  Recommendations regarding ground water or road pavement structure. Note: Further to receipt of the No-Objection to the Final Pavement Design.ROADWAY DESIGN MANUAL types of pavements and connections between old and new pavements. ground water level and soil layers along project roads. Appendix C – Geotechnical Study Data  Plan of borehole and test pit locations. The GIS format is to be discussed and agreed with the ADM’s Pavement Design Reviewer and GIS Specialist.  Soil profile including proposed design level.0 Part 2 – Section 600 Page 13 of 23 November 2014 . and is to be included in the Pavement Design Report submitted to ADM – Design Section for review and approval: Version 2.  Test results of boreholes and test pits.05 QUALITY ASSURANCE .PAVEMENT DESIGN The following checklist should be followed by the consultant during the pavement design of road projects as part of the pavement design quality assurance process. 602. Appendix D – Pavement Design Calculations  Detailed calculations of different designed pavement sections. soil replacement or road construction 6 Input Pavement Layers Material Coefficients  Layer coefficient (ai) for different pavement layers  Drainage factor of granular base course and sub-base layer 7 Pavement Design Calculations  Calculation of required SN for each pavement layer  Several Design Options  Pavement Type Selection is justified  Asphalt Layer(s) Thickness has been minimized  Pavement Design is Value-Engineering Optimized  Pavement Maintenance Type and Cost considered  Consistency of Pavement Design with Adjacent area  Longer Design Life or less pavement thickness  Less Pavement Distresses are considered in Pavement Design  Pavement Wearing Surface Friction considered  Cost saving is considered  Constructability of selected design considered  Saving in Raw Material. objective.)  Land use of project and adjacent areas  Road hierarchy of roads included in project scope 2 Clear Reference Standards of Pavement Design 3 Basic Input Design Data for each road class  Reliability (R)  Standard Deviation (So)  Standard Normal Deviate (ZR)  Skid Number. Ld. water and energy consumption  Studying the utilization of un-traditional solutions. such as pavement recycling. etc. including tie–in details for different types of pavements Geotechnical Study Data  Plan of boreholes and test pits locations  Soil profile including proposed design level. etc.  Calculation of W 18  Construction Traffic Volume and Truck Loading is considered 5 Input Design Geotechnical Data  Project Geotechnical Report Results  Selected value of soil CBR  Water table condition and concerned recommendations of Geotechnical Study  Soil MR value and method of MR calculation  Geotechnical recommendations to be adopted in Pavement Design. ground water level and soil layers along project roads  Test results of boreholes and test pits  Recommendations regarding ground water or road pavement structure  Detailed calculations of Pavement Design options Part 2 – Section 600 Page 14 of 23 November 2014 .0 General  Project Location Map  Land Use Plan (for different land use inside the project)  Road Hierarchy Plan Pavement Design Drawings  Plan of different pavement types  Pavement structure details for all types. Texture Depth and Aggregate Properties 4 Input Design Traffic Data  Summary of Traffic Study results  Selected peak hour volume(s)  Traffic Classification Percentages  Calculated Average Daily Traffic ADT  Traffic growth factor along pavement design life  Truck factor for different types of traffic vehicles  Selected Traffic Parameters. scope. Dd.ROADWAY DESIGN MANUAL PAVEMENT DESIGN CHECKLIST No. area. including details of soft soil and high water table conditions  Construction details. 1 Item Yes No N/A Remarks Existence of Basic Project Information  Project information (location. asphalt mix additives and recycled materials to achieve more sustainable pavement designs 8 Attached Drawings and Related Reports 1) 2) 3) Version 2. reduce life cycle cost.  Reduction in construction time for pavement works.  Savings in raw materials and energy during construction. Combining a stabilization Geogrid with a granular material results in a composite layer known as a “mechanically stabilized layer”. The major objective of the application of Geogrids in mechanical stabilization of granular pavement layers is to add structural value to the overall pavement structure.ROADWAY DESIGN MANUAL 603 ADM ACCEPTANCE CRITERIA FOR MECHANICALLY STABILIZED FLEXIBLE PAVEMENTS USING GEOGRIDS 603. raw material and energy consumption during construction and minimize carbon emissions.01 INTRODUCTION Implementation of sustainability concepts is a major objective for roads and infrastructure projects under the jurisdiction of ADM.e. life cycle cost. The following provides information for pavement designers who wish to use Geogrid products Version 2. increasing the modulus of the aggregate layer. the application of these benefits is not simply based on the product characteristics of the Geogrid product alone. It has become clear that these performance properties can be quantified from laboratory testing but must be verified by full scale trafficking trials carried out by an internationally recognized testing facility. safety.  Reduction of pavement construction costs and life cycle cost. However. Project function. performance. It is more than just employing the right designs and construction techniques.  Reduced carbon emissions. The primary mechanism of the Geogrid contribution in a full depth pavement structure can be summarized as lateral confinement of aggregate particles. quality. must be correctly identified and quantified for inclusion in pavement calculations. optimized energy and raw material consumption as well as minimized impacts on the natural environment and public health are all major considerations of aimed sustainable projects. granular base or sub-base material). ADM experience from actual projects has shown that the use of Geogrid in sustainable pavement design has provided:  Longer service life and/or reduced required pavement thickness for the same pavement design life. which in turn increases the load-carrying capacity and improves pavement structural performance. technological advancement.0 Part 2 – Section 600 Page 15 of 23 November 2014 .  Reduced risk related to construction quality of pavements. which will have improved performance properties. The effect of the Geogrid on the individual pavement layer in which it is included (i. in order to safeguard the environment and public health. 603. Version 2. laboratory derived methods shall be verified with evidence from field trials where the Geogrid product line proposed has been used to form a MSL and has had standard cyclic plate loading tests (as per AASHTO T294) carried out to evaluate surface modulus values. as well as guidance on the criteria ADM will use to determine suitability of the Geogrid products selected. These should be made available for submission to ADM. the aggregate particles partially penetrate into the apertures and abut against the ribs of the Geogrid.g.The class of manufactured products that vary by no more than one product parameter (e. All other parameters remain the same with respect to the manner in which the elements associated with the final product are assembled into a stable geometry. Geogrid Product Line .ROADWAY DESIGN MANUAL within ADM pavement projects.02 DEFINITIONS AND TERMINOLOGY Geogrid – An open grid-like mesh formed of polymer materials with stiff integral junctions or ribs and apertures. Stabilization Geogrid .The mechanism by which the stabilization Geogrid and the aggregate interact under applied load. During the placement and compaction of a granular layer over a Geogrid. This is the result of the mechanical effect of confinement on an aggregate layer. the MSL provides structural benefits to the whole pavement to allow increased pavement life or reduced pavement thickness. Consistent laboratory based methods (such as triaxial testing as per AASHTO T307) for measuring modulus enhancement of the stabilized layer are yet to be finalized.0 Part 2 – Section 600 Page 16 of 23 November 2014 .A composite layer comprising stabilization Geogrids and a defined thickness of granular fill (base or sub-base) having greater serviceability and increased modulus when compared to the equivalent thickness of non-stabilized granular fill. Modulus Enhancement . Therefore. used to reinforce or stabilize soils. When incorporated into a pavement structure.A Geogrid where the specific function of stabilization has been identified and associated with a product line by an independent approvals authority as being distinct from the reinforcement function. Mechanically Stabilized Layer (MSL) . sufficiently large to allow strikethrough of soil particles. sheet thickness in the case of punched and drawn Geogrids or number of filaments in the case of woven or knitted Geogrids). Interlock .Stabilization is defined as the beneficial consequence on the serviceability of an unbound granular layer via the inhibition of the movement of the particles of that layer under applied load. The stabilization Geogrid will be defined by specific stabilizationbased product characteristics. resulting from the mechanism of interlock provided by a stiff Geogrid structure.The increase in modulus of a MSL.The effect of the mechanism of interlock by which the structure of the stabilization geogrid restrains the aggregate particles. Confinement . compared to an equivalent nonstabilized layer of equal thickness. Stabilization . according to continuous research studies and communications with material suppliers and pavement Version 2. TBR values are only relevant to the specific pavement section tested. asphalt layer(s) strength and thickness. Utilized in Stabilization/Reinforcement of Base Course (and/or) Sub-base Layers of Flexible Pavements” in June 2012.The contribution of a Geogrid in a pavement structure is variable and influenced by a change of subgrade soil strength. The TBR concept can be helpful in quantifying and comparing results of trafficking trials. Base Course Reduction Factor (BCR) . aggregate type and subgrade strength. Traffic Benefit Ratio (TBR) . This included material and design requirements that should be fulfilled by supplier.03 ACCEPTANCE CRITERIA In order to standardize material and design requirements for utilizing Geogrids in the mechanical stabilization of granular pavement layers of Abu Dhabi roads. sometimes referred to as the Traffic Improvement Factor (TIF). 603. designer and contractor. This document is under continuous update and development.The ratio of the number of load cycles on a stabilized pavement section to reach a defined trafficking load to the number of load cycles on a nonstabilized pavement section with the same material properties and geometry (layer thicknesses). design parameters expressing the Geogrid contribution in the pavement structure should be derived from performance-based evaluation. Evaluation of Geogrid Benefits . Characterization of layer enhancement is subject to continuous review and update to include international recognized studies addressing different material characterization methods. the ADM Technical Team developed the first revision of “ADM Approval Process of Geogrid Materials. resulting in a MSL whose effect is evaluated and defined by various combinations of pavement layer thickness. Therefore. The LCR can then applied to directly affect the “Structural Number” of the base or sub-base material component of any pavement design case. If TBR values are to be used in the evaluation of an ADM pavement. geometry and subgrade condition that apply to the project.The percentage reduction in stabilized base or sub-base thickness from the non-stabilized thickness with the same material constituents for the same defined trafficking load. base (or sub-base) strength and thickness. The improvement offered to the pavement performance by Geogrid materials can be expressed in different ways: Layer Coefficient Ratio (LCR) .The effect of the stabilization Geogrid on a granular layer. The LCR is dependent on evaluation of a variety of full-scale trafficking trials to allow predicted trafficking performance to be verified with actual trafficking trial data. TBR values derived for one pavement section cannot be applied to a pavement section with differing material properties or geometry.0 Part 2 – Section 600 Page 17 of 23 November 2014 .ROADWAY DESIGN MANUAL Note: International studies are currently seeking to characterize the stabilized layer enhancement utilizing Resilient Modulus. they must be derived from full-scale trials based upon the specific pavement materials. : R50-09) provides the most recent advice to pavement designers interested in incorporating Geogrids in their pavements. and fulfilling all ADM regulations and requirements related to Geogrid material properties and performance.03. In order to be accepted by ADM.ROADWAY DESIGN MANUAL specialists.01 Verification of Material Characteristics Technical characteristics of Geogrid materials should be verified and certified by an independent Third Party Laboratory (to be approved by the ADM Material Quality Section). US Corps of Version 2.03. AASHTO document (Ref. engineers are encouraged to affirm their designs with field verification of the pavement performance. Material and design requirements are summarized in the following sections: It is essential to confirm that a Geogrid material is accepted by ADM and has “Approval for Application” for utilization in the mechanical stabilization of paved roads. Previous Geogrid material approvals for similar applications in previous projects are required to be included in a comprehensive material submittal to ADM Material Quality Section for review and approval (previous case studies in the UAE and GCC are preferred). There is recognition that as pavement design procedures used experimentally derived input parameters which are Geogrid specific. the material is not considered suitable for ADM “Approval for Application”. 603. the primary source to quantify the effect of the stabilization Geogrid to be used within the ADM pavement design process should be full-scale accelerated pavement testing. it should comply with both the Material Criteria and Design Procedures. The APT testing should be carried out by an internationally recognized independent pavement test facility (to be approved by ADM) in compliance with NCHRP Report 512 and Synthesis 325. For practical purposes.0 Part 2 – Section 600 Page 18 of 23 November 2014 . The proposed supplier shall present evidence of at least two full-scale APT trials. located at a number internationally recognized testing laboratories around the world. In cases where a material meets only the Material Criteria or Design Procedures but not both.02 Full-Scale Accelerated Pavement Testing The ability for engineers to assess the performance of Geogrids in flexible pavements has been facilitated in recent years with the availability of full-scale accelerated pavement test (APT) facilities.03 Full-Scale Independent Accelerated Pavement Testing (FS/APT) These tests are required to evaluate performance of a pavement incorporating the MSL under moving wheel loads and develop design parameters for use in a pavement design. full-scale accelerated pavement testing is considered acceptable as “Field Verification”. Examples of such facilities are the UK Transportation Research Laboratory. 603. Therefore. 603.03. The independent third party certificates verifying the technical properties shall be recent (within two years of the date of the Material Submittal). Design procedures which incorporate the benefit of a particular geogrid line shall require the supplier and/or manufacturer to demonstrate to the design engineer of record that FS/APT results for one or more products within that product line meet or exceed results generated by the design procedure.ROADWAY DESIGN MANUAL Engineers.03. 4. The design process should assess several options. The test must extend to sufficient ESAL’s to provide a realistic indication of whole-life performance. the following should be followed: 1. 3.04 Large-Scale Laboratory Testing Whilst the primary source of performance data for Geogrids must be full-scale accelerated pavement testing. in order to optimize the most suitable design option for each particular project (case by case basis). Reference should be made to the accepted facilities detailed in NCHRP Report 512. 2. and other products within the same product line. in order to seek ADM approval for these additional products. Geogrid stabilized sections must be compared with a non-stabilized paved control section. large-scale laboratory performance testing can be conducted to demonstrate performance differences between the behaviour of an ADM-approved Geogrid evaluated in fullscale testing. including conventional design (without Geogrid material) and other options. Pavement design utilizing Geogrid mechanically stabilized aggregate layers should be based on full and detailed design calculations. 603. accepted by ADM. geosynthetic benefit verifications and justification including supporting testing results provided by the Geogrid Material Supplier or Manufacturer and fulfilling all required material and design procedures summarized in this document.03.05 Acceptance Criteria of Pavement Design A .0 Part 2 – Section 600 Page 19 of 23 November 2014 . The wheel loads shall be equivalent to or exceed an 80kN (18 kip) single axle. 603.General Design Requirements For an acceptable design of a mechanically-stabilized flexible pavement with Geogrid. The rutting performance of the sections must be assessed by trenching. Optimization of the most suitable design option should be based on: Version 2. ARRB Transport Research (Australia) and CSIR Transportek. This information can be used to develop design parameters for additional members of a product line from those included in APT and it must be recorded within the independent review and validation report. South Africa. conducted by a pavement design specialist. The design submission shall include all design steps. All performance-based evaluations. then reviewed and approved by the pavement design specialist. ADM encourages the use of this proprietary software. shall contain information that at a minimum must include the specific Geogrid material designation or be properly correlated to other materials within the same product line. in addition to any other reference that may be directed by ADM Technical Staff: 1. with testing as per the reference standards. B .  Less expected pavement distresses and better serviceability. TRB (2003). ADM Pavement Design Guideline Requirements (January 2012). GMA White Paper: “Geo-synthetic Reinforcement of the Aggregate Base/Sub-base Courses of Pavement Structures” (2000).  Saving in construction raw materials.The Use of Proprietary Design Software Design software is ideally suited for pavement analysis with a variety of programs available from Geogrid manufacturers. NCHRP. No proposed equal Geogrid will be accepted based on material index properties or explanations of performance based on these properties. 7. Report 512: “Accelerated Pavement Testing: Data Guidelines”. Approval will be granted for proprietary software that has been independently evaluated and validated by an internationally recognized pavement design specialist with software development expertise recognized and accepted by ADM. 5.Design Reference Standards Design of Mechanically Stabilized Asphalt Pavement with Geogrids shall refer to the following references.  Less overall life cycle cost. Version 2. 6. water and energy consumption. but any software package incorporating design parameters representing the Geogrid performance must be approved by ADM.  Other design considerations defined by ADM Pavement Design Reviewer.  Easier and more sustainable maintenance activities.  Less carbon footprint. 4. The items described below must be performed either by. or on behalf of. Validation shall include the design methodology. C .  Easier and faster construction process.0 Part 2 – Section 600 Page 20 of 23 November 2014 . required to verify Geogrid material contribution in pavement structure. the Geogrid Material Supplier or Manufacturer. AASHTO R-50: “Geogrid Reinforcement of the Aggregate Base Course of Flexible Pavement Structures” (2009). design parameters and software functionality.ROADWAY DESIGN MANUAL  Longer service life. 2. 3. See Independent Review and Validation in Section 603.see definition of TBR in Section 603. hand calculations or ADM approved proprietary design software is to be used to carry out the design of the flexible pavement incorporating the stabilization Geogrid benefit. Step 2 With the same input parameters for pavement performance and material properties used in Step 1.Technical Report TR41. the design steps below should be followed and must be performed either by or on behalf of the geogrid manufacturer/supplier and then reviewed and approved by the ADM project design consultant: Step 1 Design a non-stabilized pavement section using the latest ADM method for the design of flexible pavements. Synthesis 325: “Significant Findings from Full-Scale Accelerated Pavement Testing”.General Design Steps To properly design a mechanically stabilized flexible pavement with stabilization Geogrid. 6. Step 5 Evaluate the carbon footprints of non-stabilized and stabilized pavement sections. Step 3 Carry out layered analysis as defined in the AASHTO 1993 method to ensure adequate layer thickness for each pavement component. Step 4 Conduct life cycle cost analyses of non-stabilized and stabilized pavement sections. the types of construction materials and associated design properties and layer thicknesses for the pavement section. European Organization for Technical Approvals . considering the modified Resilient Modulus of the stabilized road base course to determine the minimum required layer thickness for the stabilized pavement section.0 Part 2 – Section 600 Page 21 of 23 November 2014 . TRB (2004).02.06. appropriate to increase life and/or reduce pavement thickness resulting from the enhanced modulus of the resulting MSL.ROADWAY DESIGN MANUAL 5.03. NCHRP. Calculations should be based on defined performance criteria as well as the structural layer parameters. All design parameters reflecting the performance and contribution of the MSL in a pavement shall be reviewed and validated by an independent internationally recognized pavement design specialist recognized and accepted by ADM. D . Note: TBR values are only relevant to the specific pavement section tested . Version 2.  Construction cost savings. Refer to NCHRP Report 512. 603. This should include:  Project performance criteria.  Conforming design. to assess the overall benefits to the project. financial and environmental viewpoints.03.0 Part 2 – Section 600 Page 22 of 23 November 2014 . Note: Submission of alternative proposals incorporating a Geogrid must follow all of the criteria included in this document.  Guidelines for alternative proposals (see note below). Proposals shall be accompanied by documented independently reviewed evidence of the associated design along with pavement design calculations by hand or using ADM approved proprietary software demonstrating performance equivalent or superior to that stated in the performance based specification (from Step 7 above). This should include:  Expected pavement service life. No proposal for an alternative Geogrid will be accepted based on product characteristics (material index properties) or explanations of performance based on product characteristics.  Stabilization Geogrid product identification characteristics (for on-site verification purposes).  Stabilization Geogrid performance-related product characteristics.ROADWAY DESIGN MANUAL Step 6 Conduct a study comparing the non-stabilized and stabilized pavement designs described in Steps 1 to 5 above from technical. Step 7 Prepare a performance-based specification detailing the requirements of the selected flexible pavement design.06 Independent Review and Validation An independent review by an internationally recognized pavement engineering services company (approved by ADM before review) is required before a Geogrid product can be considered as a qualified product by ADM or utilized in a design procedure.  Stabilization Geogrid durability requirements.  Evaluation of the effect on carbon footprint of pavement construction. The third party shall be able to demonstrate familiarity with both the role of Geogrids and Version 2.  Life cycle cost analysis.  Pavement analysis and evaluation. Sarah R. 7. Derivation of traffic improvement and equivalent performance factors for Tensar TriAx™. ARA “Independent Review and Validation of Tensar’s Modified AASHTO 1993 Pavement Design Procedure and Verification of Spectrapave 4™ Software”.whrp. Synthesis 325: “Significant Findings from Full-Scale Accelerated Pavement Testing”. product characteristics. No.0 Part 2 – Section 600 Page 23 of 23 November 2014 .D. 0092-07-05 (July 2009). S.11: “The Method of Derivation of Traffic Improvement and Equivalent Performance Factors for Tensar TriAx™ Geogrids from Full-Scale Trafficking Trials at TRL”.01. Applied Research Association. S. as well as performance evaluation of pavements. Vol. NCHRP. quality assurance procedures and documentation. The review document shall accompany all final design proposals once complete. Sarika B. Sarkate. Dhule. 3. GMA White Paper: “Geogrid Reinforcement of the Aggregate Base/Subbase Courses of Pavement Structures”. In a written report. supporting performance testing and field experience documentation. Korrane: “Improvement of Flexible Pavement with Use of Geogrid. NCHRP. Geogrid Reinforcement of Thin Asphalt Pavements. IB / Derivation Trafficking / 29. TRB (2003). Valunjkar. Version 2. 6. 16” (2011). TRB (2004). that underlying calculations are supported by appropriate experimental procedures and that the manufacturer’s research supports the protocols and intent of AASHTO R-50. the reviewer shall validate that the design methodology proposed for use with the specific stabilization Geogrid product family is correct. 8. (2000). 603. Phase 1 Interim Report”.ROADWAY DESIGN MANUAL AASHTO pavement design principles.org): “Quantifying the Benefits of Geogrids for More Durable Pavements”.Tingle (2010). Report 512: “Accelerated Pavement Testing: Data Guidelines”.04 REFERENCES 1. US Army Corps of Engineers. 9.S. Jersey and Jeb S.S. 10. S. (April 2013). AASHTO Designation: R 50-091: “Geogrid Reinforcement of the Aggregate Base Course of Flexible Pavement Structures”. 2. Wisconsin Highway Research Program (www. 4. Independent review will examine the design methodology and proposed calculation of stabilization effect. 5. Engineer Research and Development Center: “Full Scale Accelerated Pavements Tests. 0 Part 0 – Divider November 2014 .ROADWAY DESIGN MANUAL SECTION 700 : DRAINAGE Version 2. The objective of roadway drainage design is to provide the necessary facilities which allow the public the appropriate use of the roadway during times of significant run-off and which minimize the potential for adverse effects on adjacent property and existing drainage patterns. Version 2.DRAINAGE 701 GENERAL Drainage is an important element of roadway design.0 Part 2 – Section 700 Page 1 of 1 November 2014 .ROADWAY DESIGN MANUAL SECTION 700 . refer to the separate ADM document entitled “Roadway Design Manual .Drainage”. For guidance on the design of the drainage components associated with roadway facilities. 0 Part 0 – Divider November 2014 .ROADWAY DESIGN MANUAL SECTION 800 : UTILITIES Version 2. Several Municipality Departments use designated consultants for the planning and design of their respective services.0 Part 2 – Section 800 Page 1 of 7 November 2014 . Relocated utilities will be replaced in-kind with the same size or capacity as the existing utility. which may extend beyond the limits of the proposed improvement depending on the connection requirements. Utility planning begins in the preliminary design phase and is a factor in the project scoping process that leads to identification of the final roadway geometrics. This provides for single-source responsibility for the procurement of materials and the scheduling of the proposed improvements. Such an upgrade or development work must be requested by the responsible utility agency and approved by ADM before the design of the upgraded utility can be included in the roadway project. A thorough investigation of existing utility location and condition is undertaken as an early final design activity. The ADM objective is that all road. The existing capacity may be undersized and require an increase in capacity or other utility expansions or improvements may be required.UTILITIES 801 GENERAL Utilities are an important element of roadway design. relocation and installation by the Contractor. This concept reduces Contractor delay claims and the time required for advance utility works.Existing utilities that are incompatible with the roadway geometrics will require relocation. especially in an urban environment. The Roadway/Bridge Consultant is responsible for the overall coordination and packaging of the documents into a complete and comprehensive set of tender documents. Utility Relocation . There are three categories of utility improvements: Utility Protection – Existing utilities within the project limits that have been determined to be geometrically compatible with the proposed improvements and are in good condition with an acceptable remaining service life may remain in place and shall be adequately protected from traffic loads and maintenance operations. specifications and Bills of Quantities. whilst minimizing disruption of services to the public. New Utilities . there are normally several consultants involved in the preparation of individual utility plans. as further described in Section 804.ROADWAY DESIGN MANUAL SECTION 800 .New service facilities may be required to support growth within the typical 20-year design life of the proposed roadway improvements. These may replace redundant or outdated facilities or alternatively be major trunk lines routed through the project corridor that serve a wider purpose. The actual timing and responsibility for construction of individual services will be determined on a project by project basis. infrastructure and bridge projects be developed to include all required construction of utility protection. Although contained in a single set of construction documents. The parallel development of plans and specifications by multiple consultants must be continuously monitored to avoid any conflict or contradiction. Version 2. The traffic loads consist of both construction loading and post-construction vehicular loading.01. The service authority may also have plans or projects for utility improvements in progress within the project limits. The Consultant will arrange coordination meetings with the Service Departments to identify utilities to be protected.Utilities Section. Utility data should be supplemented by field investigation of the existing facilities. Service corridors will be reserved within each project for utilities in accordance with the planning data obtained from the Utilities Section. Information on existing utilities shall be obtained from the UPD . Version 2. The agencies or municipality departments responsible for the individual services are as follows:  Water : ADWEA – ADDC and Transco (Water)  Telecommunications : Etisalat/Du  Electricity : ADWEA – ADDC and Transco (Power)  Irrigation : ADM – PRFD  Drainage : ADM .0 Part 2 – Section 800 Page 2 of 7 November 2014 . This information shall be compiled and analyzed to ascertain the status of each individual utility. including surveys to record structure locations and pipe invert elevations. The Utilities Section will provide details on the agency or department responsible for special services such as oil pipelines and national defense systems.  Distribution of services.  Proposed facility plans. relocated to the service reservations and new service requirements. The corridors are established based on the approved design concept and reflect the anticipated growth and overall needs of the individual utility agencies.ROADWAY DESIGN MANUAL 802 UTILITY PLANNING The Utilities Section of the Urban Planning Division (UPD) is responsible for master planning and coordination of utility services. Manual (by hand) excavation to locate services that are critical to the design should be performed as necessary.IRID  Sewer : ADSSC  Gas and Oil Lines : Abu Dhabi National Oil Company (ADNOC)  Fire Hydrants : Abu Dhabi Civil Defence  District Cooling : Tabreed  Road Traffic Control Infrastructure : DoT A full list of public service departments is provided in Part 1 – Section 200 of this Manual. This data will include:  Current service reservation locations.  As-built drawings. the individual service (utility) departments and/or the designated consultant at the beginning of design work. g. The reserves are generally located outside the roadway pavement in parking or pedestrian areas that are surfaced with removable materials.  Allow for constructability and/or maintenance of service facilities with excessive width. Project design drawings should show a section view of these special service reserves similar to that shown on the standard drawings. Further service reservation details for various road classifications and road corridor widths are provided in the Utility Corridor Design Manual (UCDM).  Suit the project geometrics. oil pipelines. The utility corridors are defined in close coordination with the project geometrics and UPD. 132 kV. diameter or depth. published by UPC.ROADWAY DESIGN MANUAL Once the scope of the utility works has been defined. 45º. Deviations from the standard distribution may be warranted to:  Accommodate existing utilities that would not otherwise require relocation. with the degree of deflection ideally corresponding to standard pipeline fittings (e. Special reserves for any utilities other than those shown on the standard drawings (e. The Standard Drawings show a sample of a typical service reservation corridor. This policy applies to all projects including new construction and roadway widening.g. The reserves are established within geometric criteria that are suited to the installation of pipelines and conduits. Service reserves are located for ease of construction and maintenance and to minimize disruption or damage to permanent works caused by future utility installations or maintenance operations.5º. etc) shall be provided in each project with specific approval from UPD. such as interlocking tiles and precast blocks.01. The final service reservation distribution and geometry requires the approval of UPD. The utility planning process is depicted in Figure 800. The design standards require construction of ducts for all existing. 803 SERVICE RESERVATIONS The ADM’s ultimate objective is to locate all utility services in designated utility corridors or service reservations. ADM will review and give final approval of the project utility scope of works. the Consultant will prepare separate cost estimates of the utility works that are required due to conflict with the proposed works and new facilities that are proposed for inclusion in the project by the utility agencies.0 Part 2 – Section 800 Page 3 of 7 November 2014 . and asphalt pavements of reduced thickness. Alignments are as straight as possible and angle points limited in severity. Version 2. Roadway crossings are perpendicular to the centreline and primarily concentrated at intersection locations. proposed and future services that cross roadway pavement. It is important to make a clear distinction between required works and facility upgrades. since this information will be used to determine the extent of the utility works to be included in the project and cost sharing responsibilities. CCTV. etc). 22. Refer to the Utilities Procedures Flow Chart. The tender documents are prepared based on the best available information and may be limited to the major components of a particular service. the Contractor will prepare detailed shop drawings that include refinements and adjustments to the tender drawings to reflect the conditions encountered in the field. this effort should be accomplished during the construction phase to enable preparation of detailed shop drawings that will fully define the requirements for each utility. incomplete as-built information and the harsh soil conditions make it difficult to determine the exact requirements for each service line. Final design plans. 2.0 Part 2 – Section 800 Page 4 of 7 November 2014 . Telecommunications providers normally prepare detailed plans and specifications for the work based on their record drawings of the existing telephone system and the need for relocation or protection of plant impacted by the improvement project. These drawings are normally included with the tender documents. without the benefit of an extensive manual excavation program to locate the utilities. especially minor branches and connections. The drawings will indicate the existing facilities anticipated to be protected. Based on the results of the manual excavation. specifications and BOQ are prepared as separate documents and included in the project tender document package. The drawings and BoQ are modified as necessary by the authority based on the results of the manual excavation and issued for construction. Separate Plans and Specifications Prepared by Agency Designated Consultant ADWEA/ADDC (Water) and ADSSC use a designated consultant for the design of facilities.01 GENERAL Utility design requirements will be defined after final determination of the scope of utility works by ADM. Version 2. This procedure varies with the different utilities and generally can be described under three categories: 1. relocated or abandoned as well as new pipeline requirements. The Contractor will then prepare fully detailed shop drawings for final approval by ADWEA/ADDC (Power). Figure 800. Any necessary adjustments based on manual excavation will be done through the shop drawing process in construction. The procedure and specifications for this work are outlined in the Standard Specifications. protection. The shop drawings require the approval of the designated Consultant and ADWEA/ADDC (Water) and ADSSC. ADWEA/ADDC (Power) develops schematic drawings and estimated quantities for relocation. As a result. salvage and supply of new cables for inclusion in the tender documents. Separate Plans and Specifications Prepared by Utility Authority ADWEA/ADDC (Power) and Telecommunications providers normally prepare design plans and specifications for their facilities in-house.01. In general. The final design of each utility will proceed based on the existing utility information and proposed facility requirements.ROADWAY DESIGN MANUAL 804 UTILITY DESIGN 804. rapid development. These lighting cables and irrigation lines shall be as close as possible to the kerb to avoid disturbance to the greenery. ADWEA/ADDC (Power) and the telecommunications provider will supply respective relocation quantities. Quantities.5m.02 UTILITY PROTECTION All utilities under the roadway must be protected. These methods are designed to protect the utility from induced traffic loading including construction equipment loads. All 132 kV cables required for the relocation work shall be new and shall be supplied under each contract. shall be calculated by the primary Consultant. The designs are prepared in consultation with the agency or department and the drawings are normally prepared as separate documents and included with the project tender document package. Removed and salvaged LV. except for relocation work designed by a designated utility consultant. traffic control and drainage/irrigation. These drawings will then be reviewed by ADM to obtain their approval prior to inclusion in the Tender Documents. This protection will continue under all pavements and extend beyond the back of kerb.03 UTILITY RELOCATION Utility relocation will generally be determined by the individual utility agency and is subject to approval by ADM. can be reused for the relocation works if approved by ADWEA/ADDC (Power). The utility agency standards and Specifications outline the type of protection to be used for the various utilities consisting of three types:  Concrete Slab (Precast or Cast-in-Situ). The Consultant should check that the depth of existing utilities is sufficiently below the subgrade level to accommodate the protection device.ROADWAY DESIGN MANUAL 3. No utilities other than lighting.0 Part 2 – Section 800 Page 5 of 7 November 2014 . 804. Version 2. 11 kV.  Concrete Encasement.  Split Duct . Any necessary adjustments based on manual excavation will be done through the shop drawing process in construction. 22 kV and 33 kV cables. Consultant Prepared Plans and Specifications The prime consultant for the project is required to prepare final design plans and specifications for surface drainage. Each agency will supply their relocation design drawings for inclusion in the project documents. Quantities for the supply and salvage items shall be as estimated by ADWEA/ADDC (Power) for each project. underground cables and irrigation pipes shall be installed along the central median parallel to the roadway.Concrete Encased. lighting. edge of shoulder or at the duct end wall constructed at the end of the duct by 0. excluding joints from site. Supply of all materials required for electrical relocation works shall be included in each contract. 804. ROADWAY DESIGN MANUAL 804. in the top of the duct end wall concrete. 804. Duct bank ends are terminated outside the permanent pavement in a reinforced concrete end wall structure that allows access to the duct ends without damaging the integrity of the structural pavement section. Existing facilities such as cables or conduits may be placed in split ducts and concrete encased. These are required at all multiple duct service reserve crossings. sewer lines.06 NON-DISRUPTIVE ROAD CROSSINGS Utility crossings of completed permanent works.0 Part 2 – Section 800 Page 6 of 7 November 2014 .05 UTILITY LOCATIONS With the exception of lighting cable and irrigation distribution lines. there shall be no construction of utility lines such as power distribution lines. Utility lines can be installed in service reserves under sector roads or parking areas where asphalt pavement is reduced in thickness. Ducts are installed where pavements with asphalt or non-removable pavers cross over the service reserve. Contingency ducts or alternative routes should be used to accommodate the service requirements wherever possible. the ADM policy requires the design to specify non-disruptive methods (pipe jacking) or tunnelling to cross the facility. Utilities of all kinds shall not be constructed under main roadway asphalt pavement. Version 2. water lines. These ducts may be designed to accommodate existing or proposed service facilities with spare or reserve capacity for future (contingency) installations. This should be a performance-based specification to offer the Contractor flexibility in selecting the equipment and methods. storm water lines or any other lines in the central median of primary roads. All duct crossing locations are to be marked in the field with permanent markers placed at the end of the duct or set. especially primary roadways are to be avoided. 804.04 CONTINGENCY DUCTS Contingency ducts are required at roadway crossings for future services to be located in service reserves and at other specific locations established by the utility authority. When the crossing of primary roadways is unavoidable. 0 Part 2 – Section 800 Page 7 of 7 November 2014 .ROADWAY DESIGN MANUAL Figure 800.01 Utility Procedures Flow Chart Version 2. 0 Part 0 – Divider November 2014 .ROADWAY DESIGN MANUAL SECTION 900 : TRAFFIC ENGINEERING Version 2. ROADWAY DESIGN MANUAL SECTION 900 . Version 2.0 Part 2 – Section 900 Page 1 of 1 November 2014 .TRAFFIC ENGINEERING 901 GENERAL Refer to the ADM “Traffic Control Devices Manual” for guidance relating to traffic engineering and the DoT for Road Traffic Control Infrastructure. 0 Part 0 – Divider November 2014 .ROADWAY DESIGN MANUAL SECTION 1000 : LIGHTING Version 2. At the time of issue of this Manual. Well designed lighting allows the driver to quickly recognize roadway features such as alignment.ROADWAY DESIGN MANUAL SECTION 1000 . delineation.  DMA Lighting Specification – Parks.  UPC . mounting types. New guidelines which include the use of LED lighting are now applicable and these will supersede the guidelines provided in this Manual in the case of any conflict. A well illuminated roadway increases safety by allowing drivers to identify potential hazards or conflicts.  DMA Abu Dhabi Public Realm & Street Lighting Handbook – (due for publication in 2014/2015). but the latest versions applicable at the time of project implementation should be followed. the last publication of the first four documents in the above list was in November 2011. Public Realm and Architectural Lighting.LIGHTING 1001 ROADWAY LIGHTING All new projects are to be designed using LED lighting systems (or equivalent alternative technology). Lighting Poles and Public Lighting Management System. These Guidelines and Specifications. Reference should also be made to other lighting guidelines and quality initiatives. including the following:  Department of Transport (DoT) – Roadway Lighting Manual. Guidelines included below relating to the use of high pressure sodium or metal halide lamps apply to the maintenance of existing lighting facilities and in situations where it is agreed that an area which currently uses these types of lamps is to be extended using the same lighting technology. Version 2. can be found in the following DMA published documents:  DMA Lighting Specification – Roadway/Parking. including light pollution). etc.  Estidama (sustainability issues.  ADM Project Compliance Checklist Tables for Tunnels and Underpasses.  ADM Project Compliance Checklist Tables for Roadway Lighting Projects to DMA Lighting Specifications. Tunnels/Underpasses.  ESMA (UAE lamp regulations).  Abu Dhabi Quality Control Council (ADQCC) – Regulations and Guidelines covering lighting materials. 1001.Guidelines. including the quality control and certification of LED luminaires and quality marking. which cover the choice of lighting and all other details such as power supply.01 GENERAL The main function of roadway lighting is to improve driver visibility.0 Part 2 – Section 1000 Page 1 of 10 November 2014 . The improved driving environment in turn improves traffic operations. As a result of increased access to commercial and private property. buses and LRT). Arterials and Frontage Roads .Arterials serve moderately high volumes of traffic at lower speeds than freeways and expressways.0 Part 2 – Section 1000 Page 2 of 10 November 2014 . at the time of concept planning. Adequate lighting for pedestrian movements and public transportation’s frequent stopping. However. Although their primary function is to move and maintain uninterrupted traffic flow. and pedestrian crossings.As freeways and expressways are wide and have higher traffic speeds. traffic volume can be heavy and frequently interrupted. Single-sided pole solutions must be used wherever possible. traffic signals. assists drivers identify roadway facilities and acts as a unifying design element. Interchanges . 1001. increased commercial development along arterials means increased pedestrian movements and possibly the need to accommodate public transportation (taxis. Lighting design responsibility generally encompasses entire roadways within the project limits. capacity and safety. However. the design responsibility may be reduced or expanded by the Municipality. especially in residential and commercially developed areas. Lighting considerations are much the same as for arterials. signs and the resulting crossing and turning conflicts. general street lighting requirements are inadequate for freeway and expressway lighting. Also.02 LIGHTING DESIGN CONSIDERATIONS Freeways and Expressways . Arterial lighting must also blend with commercial development lighting to avoid combinations which detract from the overall lighting or result in poor visibility. Version 2. unless there is a justification for road-side locations due to streetscape illumination requirements or median public transit systems. High lumen lamps in conjunction with high mast poles are used to illuminate large roadway areas only when conventional discharge lamps are used. they frequently have busy at-grade intersections requiring traffic control devices. the pole height is limited to 20m in the case of LED fixtures. Lighting continuity is recommended for aesthetic and functional reasons. Median pole locations must be used wherever possible. sector roads. must accommodate an even heavier volume of pedestrian movement.ROADWAY DESIGN MANUAL intersections. These at-grade intersections require greater visibility for traffic signals.Interchanges require lighting to provide an overall spread of light not confined to the basic driving lanes to enhance traffic safety through high visibility. The designer should consult ADM as to any variation in the design requirements. loading and unloading of passengers is vital to safety along arterials. compared to arterials. Although traffic speed is low. Sector Roads – The primary function of a sector road is to provide direct access to adjacent properties. ramps. The aim is to design with fewer poles and this requires a greater flexibility in their location. traffic signs. due to their directional optics designed to reduce glare and improve uniformity. Individual designs shall specify lighting levels as advised by ADM at the design phase. as well as meeting environmental objectives.ROADWAY DESIGN MANUAL Intersections and Pedestrian Crossings .0 to 4. Note on the Use of Table 1000. the illumination level at an intersection of two at-grade roadways is the sum of the illumination of the two roadways.5 Interchanges 22 2:1 HPS Cut-off Type V 20 or 30. Recommended illumination level indicates the minimum average allowable. pedestrian security or to enhance appearance. If necessary for traffic safety. Version 2. Areas of traffic conflict would have high levels of illumination equal to the sum of values recommended for each of the intersecting roads. Metal Halide and LED for sign lights will provide good contrast and easy differentiation from high pressure sodium roadway lighting.0 Part 2 – Section 1000 Page 3 of 10 November 2014 . Generally. 1.5 Main Roads/Arterials 22 2:1 HPS or MH Rectilinear Sharp Cut-off 14 3:1 HPS or MH Rectilinear Sharp Cut-off 10 2:1 HPS or MH Rectilinear Sharp Cut-off Sector Roads/Ramps Crosswalks Ramp Terminals and Traffic Conflict Areas Parking Areas Sidewalks away from road 15 a 33 40 b 15 10 a Light Source 2:1 Match Road 3:1 HPS or MH 3:1 HPS Pole Height (m) Lantern 14-20 or 30. the lighting locations should be selected to define the various elements more clearly.01 Illumination Requirements (See note above regarding use) Roadway Minimum Illumination (Lux) Uniformity Ratio Freeways and Expressways 22 2:1 HPS Cut-off Type III 20 or 30. lighting will be upgraded to suit conditions.Lighting intersection and pedestrian crossings is of particular concern and must be adequate for traffic and pedestrian security. a b On high volume roads.01 This table should only be used for the maintenance of existing lighting facilities and in situations where it is agreed that an area which currently uses these types of lamps is to be extended using the same lighting technology.6 Light sources:  HPS – High Pressure Sodium  MH – Metal Halide Notes: Lamps for sign lighting should be a different colour from the roadway.5 Cut-off Type Rectilinear Sharp Cut-off Decorative 10-14 10 4. Table 1000. Side roads and ramps shall have the same light source as the adjacent main roads. Light Source . Illumination criteria and calculations are based on the Illuminating Engineering Society’s (I. Metal halide gives a whiter light and improved colour rendering. Lanterns mounted on 14m poles shall be 400 or 1000 Watt high pressure sodium or metal halide. LED fixtures can be provided with different colour temperatures from 4000K to 6000K and high colour rendering. Where UL values are provided. They produce uniform illumination and minimum glare. this refers to the overall average maintained illumination of the roadway lanes along the centreline.ROADWAY DESIGN MANUAL 1001. It is also termed UO. as per Table 1000. These lanterns are designed to illuminate a relatively large area without spilling light into adjacent areas.01. or LED sized appropriately for the area and roadways.Light sources shall be as identified in Table 1000. Uniformity Ratio . divided by the lowest value at any point along the line. Illumination .) Standards modified to meet the requirements of ADM and DMA. Lighting Poles and Public Lighting Management System and as modified during the design phase if advised by ADM.A Uniformity Ratio (UR) is defined as the overall average maintained illumination of the roadway design area. metal halide or high pressure sodium shall be selected to blend with the surroundings on sector roads. LED. They shall be of adequate design to operate at mounting heights of up to 30. Tunnels/Underpasses.“Sharp cut-off” lanterns are proposed for roadway lighting.S. Roadways not identified in this manual will use a light source as directed by ADM. Lanterns mounted on 10m poles shall be 400 Watt high pressure sodium or metal halide.01 and the DMA Lighting Specification – Roadway/Parking. Lighting Poles and Public Lighting Management System summarize the illumination requirements for various roadways. divided by the lowest value at any point in the area. Tunnels/Underpasses. and provide efficient even illumination. or LED Version 2.E. The requirements of Estidama must also be adhered to.01 and the DMA Lighting Specification – Roadway/Parking. Lanterns shall be mechanically strong and easy to maintain. with full cut-off. High pressure sodium lamps provide a near monochromatic yellow/white colour.Illumination levels quoted represent the lowest average maintained levels considered appropriate for each kind of roadway or walkway in the various areas. It is important that the lighting design be compatible with the surrounding area.0 Part 2 – Section 1000 Page 4 of 10 November 2014 .03 ILLUMINATION REQUIREMENTS Table 1000.5m (20m maximum in the case of LED) and be able to withstand sustained wind speeds of 160 kph with 208 kph gusts. as per the area’s requirements and/or as agreed with ADM. Lantern and Lamp Selection . On other major thoroughfares.S. Tunnels/Underpasses. Lantern configuration and light distribution to be selected to suit the parking area geometry.0 Part 2 – Section 1000 Page 5 of 10 November 2014 . such as reversing.02 ILLUMINATION REQUIREMENTS Light source to be high pressure sodium. Lighting Poles and Public Lighting Management System. but where substantial lighting requirements remain. as applicable. and provide efficient even illumination.ROADWAY DESIGN MANUAL sized appropriately for the area and roadways. Lighting is also critical for vehicle manoeuvres. Lighting Poles and Public Lighting Management System as applicable.5m or 18-20m poles shall also be used at all interchanges.5m) or 18-20m poles are proposed for applicable interchanges and between closely spaced interchanges when conditions permit. metal halide or LED.High mast lighting (30. Lanterns shall have optical systems sealed against moisture. Standards and the requirements of the DMA Lighting Specification – Roadway/Parking. with full cut-off. 1002. On major thoroughfares not suitable for high mast lighting. Lighting Poles and Public Lighting Management System.03 LANTERN MOUNTING HEIGHT 10m high poles shall be used for all parking areas. and cut-off characteristics are to be designed based on I. High mast lighting should only be used on main roads when light height will not substantially interfere with nearby buildings. 1002.E.01 GENERAL The function of light sources in parking areas is to give an overall view of the parking area and provide a measure of security. and be mechanically strong and easy to maintain. Tunnels/Underpasses. dirt and insects. Glare control for the mounting height specified.5m poles) or 18-20m poles shall be used on urban freeways and expressways with wide medians where one row of 14m poles is not suitable. Tunnels/Underpasses. pole heights should be 14m. Version 2. The 30. 1002 PARKING AREA LIGHTING 1002. Single or multiple lanterns should be used to provide uniform illumination of the roadway. selected to blend with the surroundings as per Table 1000. poles should be 14m high and be placed at the side or primarily in the median of the roadway. The specific requirements for LED fixtures are contained within the DMA Lighting Specification – Roadway/Parking.01 or the DMA Lighting Specification – Roadway/Parking. High-mast lighting (30. Lantern Mounting Height . e. to buildings themselves and to the other pedestrian walkways.01 or the DMA Lighting Specifications.0 Part 2 – Section 1000 Page 6 of 10 November 2014 .04 LANTERN SELECTION Ornamental lighting of appropriate design and height for pedestrian needs should be proposed for sidewalks along buildings and in public realm and streetscape areas. Tunnels/Underpasses. 1004. all additional lighting control requirements are set out within the DMA Lighting Specification – Version 2.02 ILLUMINATION REQUIREMENTS As per Table 1000. telephone booths and sidewalk fixtures). 1004 LIGHTING CONTROLS 1004. as approved by ADM. For new projects. All sidewalk lighting levels are to be achieved. Table 1000.02 LIGHTING CONTROLLER REQUIREMENTS Lighting shall be controlled by a photocell or 24 hour timing switch. The Project Design Manager should consult with ADM as to the exact nature of the requirements at the time of concept planning.01 GENERAL These items provide required electrical connections and controls to all roadway lighting. 1003. Control cabinet requirements to be as specified in the Standard Specifications. unless otherwise directed by ADM.04 LANTERN SELECTION Lanterns shall be as detailed in the General Specifications.01 GENERAL Sidewalk lighting provides visually pleasant and decorative illumination to sidewalks adjacent to buildings. 1003. Separate sidewalk lights/poles will be provided only for areas specifically advised by ADM. Lighting Poles and Public Lighting Management System as applicable. with lamps and fixture heads selected to match the adjacent roadway and any existing sidewalk lighting. Special pole heights and lantern types may be required to meet special situations. 1003. 1003 SIDEWALK LIGHTING 1003. by the light from the roadway lighting fixtures.01 and the DMA Lighting Specification – Roadway/Parking.03 LANTERN MOUNTING HEIGHT Separate sidewalk light poles shall generally be 4-6m high. decorative lighting and street furniture lighting items (i.ROADWAY DESIGN MANUAL 1002. wherever possible. bus shelters. 03 DESIGN STANDARDS AND PROCEDURES Control cabinets should be located in the median where feasible. All new project work shall have utility corridors designed and provided as per the requirements of the UPC Abu Dhabi “Utility Corridor Design Manual” (UCDM) and as per ADM requirements. Underground distribution to the lighting units utilizes four conductor and steel wire armoured XPLE insulated cables. Conductor size will generally be 25 mm2 for all 30. Wherever the lighting cables are proposed outside the service reserve. will be allowed. Cables shall be direct buried under sidewalks and interlocking pavers used in parking areas except at the entry or exit of sector roads or parking areas where PVC ducts shall be provided.ROADWAY DESIGN MANUAL Roadway/Parking. Separate earthing is required only at the terminal pole of each circuit. Branching of underground cable circuits from all lighting units. except 4-6m poles. Tunnels/Underpasses. All new project work shall have utility corridors designed and provided as per the requirements of the UPC “Abu Dhabi Utility Corridor Design Manual” (UCDM) and as per ADM requirements. They should be installed between the foundation race way conduit and the electrical conduit.0 Part 2 – Section 1000 Page 7 of 10 November 2014 . 1004. There should be a minimum of one spare duct at each crossing. Lighting Poles and Public Lighting Management System. 1005 POWER DISTRIBUTION Electric service is 415/240 volts. There shall not be any intermediate joints in the lighting cable circuitry except the terminations in the lighting units or in the junction boxes. Version 2. the cable route shall be immediately adjacent to the kerbline. All PVC conduits and ducts for underground cable lighting circuitry shall be a minimum of 10cm diameter. Separate lighting road crossing ducts are not required at these locations. Type IV or polycarbonate pull boxes shall be used adjacent to light pole foundations in paved areas except where interlocking pavers are used. Cables under interlocking tiles at the entry or exit of sector roads and parking areas shall be through concrete encased PVC ducts. The underground lighting cables shall be installed along electrical service reserves in all possible cases. 50 Hz system furnished by ADWEA/ADDC (Power). The lanterns will be connected in phase sequence to provide a balanced three-phase load. All light poles and fixtures shall be earthed through the cable armouring. four-wire. three-phase. the available electrical ducts shall be used. The maximum voltage drop in the outgoing circuits beginning at the control cabinet shall be 4% (four percent). This service shall be provided at the lighting control cabinets. street furniture and decorative lighting units.5m and 18m to 20m light poles and 10 mm2 or 16 mm2 for all poles in the range 4m to 14 m. Where lighting cables are proposed along the service reserves at road crossings. ADM and ADWEA/ADDC (Power) are jointly responsible for the technical specifications of the control cabinets and both will review the contractor submittals covering this item during the construction period.01 CONCEPT DESIGN All design concepts are to be prepared in line with the principles of Estidama. ADWEA/ADDC (Power) may suggest/advise of criteria or improvements in lighting for ADM and its Consultant to consider in design and construction. pull boxes and conduits. 1007 DESIGN REQUIREMENTS The following provides a summary of the main requirements associated with lighting design at the various stages of project development: 1007. The Consultant shall prepare a lighting strategy plan in accordance with the principles of Estidama. how sustainability criteria and their necessary monitoring will be addressed and implemented to achieve which specific Estidama credits. including a simple visual representation and description of the overall lighting plan. UPC Public Realm Design Manual. ADM is responsible for the technical specifications and sizing for the electrical power supply for the lighting system from the control cabinet to the lighting poles inclusive. ADM (DMA) lighting standards and other relevant standards.0 Part 2 – Section 1000 Page 8 of 10 November 2014 . This information can be sourced from the following website: http://estidama. uniformity ratios and distribution and differences in brightness of the roadways.org. Power supply from the regional network to the control cabinets is the responsibility of ADWEA/ADDC (Power). This criterion covers illumination levels. and have the right to inspect such construction in the field. including underground cable circuits. ADWEA/ADDC (Power) responsibility is limited to advising of its requirements for maintenance and access to the control cabinets for inclusion in the Specifications. The Consultant shall propose which rating systems are being referenced.ROADWAY DESIGN MANUAL 1006 DESIGN AND SUPERVISION RESPONSIBILITIES ADM is responsible for the lighting criteria standards to light the roads. ADM and its Consultant are responsible for adherence to the lighting specifications. fuses. However. sections and elevations (based on the approved concept option). These shall include a narrative and graphics to illustrate the strategy. UPC Urban Street Design Manual. some typical fixture type images and narrative addressing light pollution issues and control strategy. Version 2. Pole height and spacing strategies shall be prepared and target luminance/illuminance levels agreed. with supporting demonstration/calculations. ROADWAY DESIGN MANUAL 1007. The aim of the Preliminary Lighting Strategy is to improve the quality.  Drawing Deliverables: 1.03 DETAILED DESIGN The Consultant shall provide fully detailed. consistency and efficiency of lighting in public spaces. full load calculations. sections. including:  An image of each fixture or element. The Lighting Strategy Plan shall also include a control strategy and lighting control cabinet locations. to be submitted to ADM for approval. 3. the Consultant shall carefully review the proposed street lighting layouts in terms of road safety. Preliminary Lighting Schedule. elevations. expected levels of light and associated lighting calculations and corresponding schedule of lighting fixtures to prove DMA Lighting Specification project compliance. full lighting calculations. annotated. for all designs having a speed limit in excess of 60 kph or in locations where a high traffic volume is predicted.  Estimated quantity of fixtures by type. the Consultant shall prepare a Preliminary Lighting Plan identifying fitting locations/spacings by type.  Envisaged lamp types.0 Part 2 – Section 1000 Page 9 of 10 November 2014 . specifically expected costs and energy saving calculations. 1007. referenced and circuited lighting layout plans. Version 2. whilst minimizing light spill. which describes each intended light fixture. Preliminary Lighting Plans. details and other graphics identifying all lighting and infrastructure elements to prove DMA Lighting Specification project compliance. The Consultant shall also produce a Lighting Schedule. Preliminary Lighting Details. plan enlargements.02 PRELIMINARY DESIGN Based on the preliminary design layout. glare and other potential light pollution issues. including poles and arms.  Any sustainable characteristics and/or Estidama minimum requirement characteristics. In addition. The Consultant shall also produce a Lighting Schedule that describes and specifies outright each intended light fixture including:  An image of each fixture or element. This review shall give careful consideration to the need of protective barriers and the findings shall be summarized by the Consultant in a Street Lighting Safety Review and Strategy Report. 2.  Dimensions and installation requirements as applicable. Version 2. Detailed Lighting Details.  Drawing Deliverables: 1. colour.ROADWAY DESIGN MANUAL  Actual lamp and gear specifications including colour. lamp life and any dimming capability. Detailed Lighting Schedule.  Any sustainable characteristics and/or Estidama minimum requirement characteristics. corrosion resistance. Detailed Lighting Plans. IP and IK rating.0 Part 2 – Section 1000 Page 10 of 10 November 2014 . 2.  Material.  General maintenance requirements. costs and energy saving calculations. finish.  Detailed specification with chosen manufacturer and product reference. 3. temperature. specifically expected.  Estimated quantity of fixtures by type. 0 Part 0 – Divider November 2014 .ROADWAY DESIGN MANUAL SECTION 1100 : ROADSIDE DEVELOPMENT Version 2. Mosques.0 Part 2 – Section 1100 Page 1 of 3 November 2014 . and will determine its location and size. Guidelines for providing irrigation ducts and appurtenances are as follows: 1. 1102. Embassies and/or other significant features within the sector often require special (nonstandard) treatment.01 IRRIGATION DUCTS All irrigation facility roadway crossings shall be accommodated within ducts. pump-house structure. Version 2. The Design Project Manager is responsible for liaising with the PRFD to ensure that the design is in accordance with their requirements. so that they can review the landscaping and irrigation system.ROADSIDE DEVELOPMENT 1101 LANDSCAPING Hard and soft landscaping and associated irrigation system for the roadside areas and medians is to be coordinated with the PRFD. Special permission from the Municipality is required for the removal of any green (planted) area. interior piping. as directed by ADM. Newly created areas suitable for planting along with remaining green areas must be identified and presented on the General Plans. PRFD will determine if a reservoir is required on a project.  Abu Dhabi Additional Irrigation Design Guidelines.  DMA – Subsurface Irrigation Systems Guideline Manual. 1102 IRRIGATION It may be required to design an irrigation reservoir with electrical and water services. Each sector must be considered individually. Guidance on the design and use of irrigation systems can be found in the following publications:  ADM Design Standards Manual for Irrigation & Treated Sewage Effluent Systems. wiring and pumping systems. incoming services.  Abu Dhabi Public Realm Design Manual (PRDM). Ducts for irrigation lines may be Glass Reinforced Plastic (GRP) or Polyvinylchloride (PVC) pipe conforming to the Standard Specifications. including reservoir. unless designed by PRFD. Close coordination with the PRFD is essential to ensure that the irrigation design is completed early enough to be incorporated into the Tender Documents of the roadway project.ROADWAY DESIGN MANUAL SECTION 1100 . noting that the requirements of local residents. The Design Project Manager must provide these plans to the PRFD. Duct crossings should be located within allocated service reservation corridors. The intent is to maintain the cover from the sideslope at 1.0m of cover.0 Part 2 – Section 1100 Page 2 of 3 November 2014 . Version 2. However. Ducts should normally have 1. The end of the ducts should extend into the verge area in un-kerbed conditions. Special treatment of slope paving may be applicable at specific locations. Ducts should be considered where maintenance roads and driveways cross irrigation lines. 1103 FENCING The Consultant and ADM will review fence requirements on a project-specific basis. 1106 STREET FURNITURE 1106. 5.5m (minimum) beyond the rear face of kerbs or sidewalks when in kerbed situations.01 GENERAL Street furniture may be provided as part of ADM projects.5m of cover is acceptable where positioning is due to conflicts with existing or proposed utilities. Specific contingency duct requirements for each project must be coordinated with the PRFD. Ducts under the roadway pavement must be aligned with each other in the median. the ducts should have approximately the same degree of cross slope as the highway. all proposed green areas shall be covered with a 300mm minimum depth of sweet sand to finished grade level. All ducts should have a nominal (1%) slope for drainage. 3. The Designer should coordinate slope paving treatments with ADM. Generally ducts will be provided under the roadway at intersection crossings. 0. The Consultant will show green areas on the General Plans and calculate the quantity of sweet sand required for the project. 1105 SWEET SAND COVERING In general. 4. In superelevated sections. both horizontally and vertically. 6.ROADWAY DESIGN MANUAL 2. The purpose is to provide pedestrian amenities and to enhance the urban environment with street furniture that has a uniform and visually pleasing design and appearance.0m (minimum) where the irrigation line comes out of sleeve. The end of ducts must extend 0. or as directed by PRFD. 1104 SLOPE PAVING Slope paving at bridge abutments shall conform to ADM standard slope paving details. Additional contingency ducts are to be located at spacings of approximately 250-300m between interchanges. during the Concept Phase. 1106. as shown on the Standard Drawings. On all types of projects.03 BUS SHELTERS Bus shelters are to be installed at bus stops. depressed roadways or noise abatement facilities may be required. any increase in the traffic noise. 1106. especially in residential neighbourhoods. installation of street furniture will be included as part of the proposed improvements. the Consultant is to mitigate. as much as possible. In special circumstances involving sensitive areas.ROADWAY DESIGN MANUAL In general. In general. For urban interchange projects. 1107 NOISE ABATEMENT The Consultant and ADM shall review any noise abatement requirements on a project-specific basis. providing shade and seating for bus passengers. Highway layouts shall be designed to accommodate bus stop locations.02 BENCHES Consultants should refer to the latest guidelines on street furniture published by PRFD. shelters and the design thereof.0 Part 2 – Section 1100 Page 3 of 3 November 2014 . Version 2. Consultants are to liaise with the DoT for bus stop locations. the Consultant should consult with PRFD to determine the types of street furniture that should be provided. street furniture will only be provided in roadway projects at the direction of ADM/PRFD. ROADWAY DESIGN MANUAL PART 3 – STRUCTURE DESIGN Version 2.0 Part 0 – Divider November 2014 . 0 Part 0 – Divider November 2014 .ROADWAY DESIGN MANUAL SECTION 100 : DESIGN CRITERIA Version 2. amendments and interim revisions.  AASHTO LRFD Bridge Construction Specifications. Version 2. Structures shall be designed and detailed in accordance with:  AASHTO LRFD Bridge Design Specifications. 2010. The AIP records the agreed basis and criteria for the design or assessment of a highway structure. in this document. but will not be adopted at this time unless specifically requested by ADM. For further details on project submission requirements (including AIP. All other codes and standards mentioned in Part 3 refer to the latest version/edition of such codes and standards.01 PURPOSE The purpose of this Part 3 – Structure Design is to provide structural design standards for bridges and other road structures in order to establish a uniform project design policy. unless otherwise directed by ADM. termed “AASHTO LRFD” in this document. The detailed design criteria defining all major design aspects shall be prepared by the Consultant and submitted as an “Approval in Principle (AIP)” Report for review and sign off by ADM. This will aid the Consultant in the preparation of drawings and specifications and ensure safe. 101. Sixth Edition. 2012 (including 2013 interim revisions). the main reference document has been changed to the AASHTO LRFD Bridge Design Specifications. The previous manual used the AASHTO Standard Specifications for Highway Bridges. termed “AASHTO LRFD Construction Specifications”. The Report shall be revised as necessary and completed as the project progresses during the Preliminary and Final Design stages. reference AASHTO LRFD US-6-M. 15th Edition (1992) as the base reference document. including associated published supplements.DESIGN CRITERIA 101 INTRODUCTION This document has been prepared to update the Roadway Design Manual first published in 1998 and subsequent interim revisions. Durability Report and Design Verification Report).0 Part 3 – Section 100 Page 1 of 13 November 2014 .ROADWAY DESIGN MANUAL PART 3 . This Part 3 of the manual provides structural engineers with a guide to the design criteria and methods of analysis applicable to bridges and other highway structures.STRUCTURE DESIGN SECTION 100 . Note that the latest 7th edition of this document was recently announced by AASHTO. refer to the ADM Consultant Procedure Manual.  The Structural Design Standards included in this document. sustainable and uniform designs. Sixth Edition. 2012 (includes 2013 interim revisions). published by AASHTO. As part of the current update. AASHTO LRFD Construction Specifications .Approval as obtained from ADM. Compliance with these structural design requirements does not in any way modify or reduce the contractual.AASHTO LRFD Bridge Design Specifications. published by AASHTO. AASHTO .American Association of State Highway and Transportation Officials. 6th Edition. the Consultant should refer to the relevant international design standards. Geotechnical Report . 2013.The Geotechnical Report including the Foundation Design Report. Particular Specifications . legal and statutory responsibilities of any party for the work carried out. The Consultant may propose more conservative criteria if it judges that such criteria are required. Luminaires and Traffic Signals”. Abu Dhabi City Municipality. However. all deviations from the criteria must be justified and are subject to prior approval from ADM. 2010.02 DEFINITIONS The following definitions and abbreviations are provided to clarify usage of terms and to avoid the need for excessive verbiage.ROADWAY DESIGN MANUAL  The latest ADM Manuals and advice notes that will be issued from time to time by ADM. consideration of local conditions shall be given in carrying out the design. published by AASHTO (reference AASHTO LRFD US-6-M). All structures shall satisfy the requirements of relevant statutory authorities. AASHTO Specifications for Structural Supports – The AASHTO “Standard Specifications for Structural Supports for Highway Signs. These requirements are for highways and bridges covered by AASHTO LRFD. 101.Load and Resistance Factor Design. 6th Edition. While adopting AASHTO LRFD.AASHTO LRFD Bridge Construction Specifications. These structural design requirements set forth minimum standards.0 Part 3 – Section 100 Page 2 of 13 November 2014 . For special structures or bridges carrying abnormal loads. LRFD . 2012 (includes 2013 interim revisions). Other technical codes shall be submitted to the ADM for review and acceptance prior to adoption in the design process. AASHTO LRFD . as produced by the Geotechnical Section or by the Consultant. Version 2. The Structural Design Standards presented hereunder shall govern over the AASHTO LRFD Design and Construction Specifications wherever these are “at variance with” or “in addition to” the AASHTO LRFD Specifications and relevant ADM Manuals. Approval .The special provisions specifically written for each individual project. wide valleys or railroads.A structure which provides for passage of a pedestrian walkway under a roadway. a highway or a railway and having a track or passageway for carrying traffic or other moving loads and having an opening measured along the centre of the roadway of more than 6. such as water.A structure of some length carrying a roadway over various features such as streets.ROADWAY DESIGN MANUAL to compliment the Standard Specifications. it is the point of intersection on the abutment wall or piling with the cap.0m between the under-copings (see note below for definition) of abutments or springlines of arches or extreme ends of openings for multiple boxes.An overpass or underpass is also called a Traffic Interchange if on and off ramps are provided to the intersecting roadway.A structure carrying a pedestrian walkway over a roadway. street or railroad. railroad or other feature. waterways.0 Part 3 – Section 100 Page 3 of 13 November 2014 . Pedestrian Underpass . All calculations and drawings should be provided in the metric (SI) system. Bridge .A structure which provides for passage of the principal route under a highway. 101. where the clear distance between openings is less than half of the smaller contiguous opening. Traffic Interchange . the Consultant may refer to AASHTO LRFD (2007) for the conversion of formulae Version 2. However. Viaduct .04 QUALITY ASSURANCE The Consultant’s Quality Management Plan shall include the requirements specified in the latest “ADM Quality Control and Quality Assurance Procedures”. The latter document provides design checklists to serve as guidance for design Consultants during the design and review processes. Pedestrian Overpass . street.” Note: The under-coping of an abutment is the point where the bridge bearing seat intersects the front face (usually near-vertical) of the abutment.A structure carrying a roadway through a hill or mountain. including supports.A structure carrying the principal route over a highway. Where there is a distinct abutment pile cap. It may include multiple pipes. Underpass .03 BRIDGE TYPES Bridge Definition . erected over a depression or an obstruction. 101. Overpass . Standard Specifications .The term “bridge” is usually reserved for structures over water courses or canyons. Tunnel .A “Bridge” is defined as a structure. as far as possible.The ADM Standard Specifications. where the cumulative span is less than 5m. checked and certified. Category 0: Structures which conform in all aspects of design. The category is to be proposed by the Designer or Assessor and outline details submitted to ADM in accordance with the latest “ADM Quality Control and Quality Assurance Procedures”. All designs shall be designed. clear. 2 or 3. such as spreadsheets. assessment and execution as stated in the ADM Roadway Design Manual and associated specifications and contain no Departures. design complexity and whole-life costs.  Multi-cell buried structures. All structures must be placed in one of four categories: 0. 1. US customary units may be used if conversion is not possible. according to the criteria described below. well organized. which may be from the same organization. It is critical that the design calculations be user-friendly.0 Part 3 – Section 100 Page 4 of 13 November 2014 . who may be from the Design/Assessment Team. The design criteria and assumptions should be clearly included in the front after the index. proposed by the Designer or Assessor and agreed by ADM.  Minor structures not situated at a very exposed site. The category boundaries are not rigid and the category selected for each proposal will be decided on a project-by-project basis. having regard to potential consequences of failure. properly referenced and include numbered pages along with a table of contents. provided they also conform to one of the following:  Single span simply supported structures with a span of less than 5m. and a proposal subsequently arises requiring a Departure. but must be independent of.  Category 3: requires verification from a Check Team from a completely separate organization. the Design Consultant must contact ADM requesting a review of the selected Category. buried rigid pipes and corrugated steel buried structures of less than 3m clear span/diameter and having more than 1m cover. the Consultant shall be responsible for thoroughly checking these tools to ensure the integrity of the structural analysis and design.  Category 2: Requires an independent verification from a Check Team. and having more than 1m cover.  Earth retaining structures with an effective retained height of less than 2m.  Categories 0 and 1: Require an independent check by another engineer. Where a structure has been placed in Category 0 or 1. etc. The summary of the analysis results and associated outcome should be included.  Buried concrete boxes. When using personal design tools created by others. if loss of accuracy would result.ROADWAY DESIGN MANUAL where applicable.. Version 2. the Design/Assessment Team. but less than 20m and having a skew of less than 25°.  Bridges with suspension systems.  Steel orthotropic decks. which require sophisticated analysis or with any one of the following features:  High structural redundancy. assessment and execution as stated in the ADM Roadway Design Manual and associated specifications and contain no Departures.  Skew exceeding 45°.  Earth retaining structures with an effective retained height of 2m or greater.  High masts exceeding 20m in height or situated at a very exposed site. Category 3: Complex structures. 1 or 3. gantry rail and gantry support systems. Version 2. novel or esoteric design aspects.  Moveable bridges.  Masonry arches with a span of less than 6.  Environmental barriers less than 3m high and without overhangs.  Buried concrete boxes.  Any span exceeding 60m. Category 2: Category 2 structures are those which are not within the parameters of Categories 0.  Unconventional. buried rigid pipes and corrugated steel buried structures with a clear span/diameter of 8m or less.  Moveable inspection access gantries. other than those in Category 0.0 Part 3 – Section 100 Page 5 of 13 November 2014 .ROADWAY DESIGN MANUAL  High masts not exceeding 20m in height and not situated at a very exposed site.5m.  Difficult foundation problems. Category 1: Structures.  Environmental barriers 3m or more in height or with overhangs.  Portal and cantilever sign and/or signal gantries with a span of less than 20m. which conform in all aspects of design. provided they also conform to one of the following:  Structures with a single simply supported span of 5m or greater. but less than 7m.  Minor structures situated at a very exposed site.  Refurbishment and strengthening of existing road tunnels. In determining a design solution.  Assessment of existing tunnels that are subject to the effects of new. Assessment and Related Construction Work In general. renewal. Design. the Consultant will be required to demonstrate to ADM that the principles of value engineering and sustainability have been considered.05 VALUE ENGINEERING AND SUSTAINABILITY As part of ongoing analysis of cost effectiveness.BD 36/92: Evaluation of maintenance costs in comparing alternative designs for highway structures. Materials. 101. repair. tunnel service buildings and service tunnels. Guidance on whole-life costing can be found in Design Manual for Roads and Bridges Volume 1 section 2:  Part 1 .  New road tunnels. the assessment of the load carrying capacity of existing structures and related construction work such as demolition.  Rock anchorages. In demonstrating the development of a sustainable solution the following should be considered: 1.  Bridges being designed in a Design and Build Contract.ROADWAY DESIGN MANUAL  Earth retaining structures with an effective retained height of 14m or greater.  Structures which are considered high risk based on consequences of failure. Version 2. refer to the requirements of the ADM “Sustainability Guidelines”.  Responsible sourcing of materials. temporary or permanent construction above or adjacent to the tunnel structure. Part 3 – Section 100 Page 6 of 13 November 2014 .BA 28/92: Evaluation of Maintenance Costs in Comparing Alternative Designs for Highway Structures. 2. the consultant is expected to consider Value Engineering in the design of all elements of a project.0  Efficiency.  Part 2 . Refer to the ADM “Consultant Procedure Manual” for more details about Value Engineering requirements. refurbishment and strengthening work that affects structural integrity must be categorized on the same basis that the original structure would have warranted. For general sustainability and environmental requirements. ROADWAY DESIGN MANUAL  Design to minimize impacts - evaluate materials against design constraints including cost, environmental impact and durability. Design for the full life-cycle and health. 3. Construction. 4. Maintenance and use. 5. Demolition. 101.06 GENERAL PROVISIONS Structures subjected to ground water table shall be checked for floatation. For underground structures and underpasses, design and construction shall be such to preclude water leakage. Design for water tightness shall include, but not be limited to, the following items:  Water stops between slabs, walls and joints.  Adequate drainage provisions.  Waterproofing system.  Control of the distribution and width of cracking.  The consideration of water tightness in the design of concrete.  Construction sequence.  Minimizing number of joints. The design shall take into consideration that the disturbance to traffic flow on the existing roads be minimized during construction. The Consultant shall design the detours, which will be approved by ADM and other relevant authorities. The design shall try not to affect, and take consideration of, the adjacent existing buildings and structures (if any) or any planned construction in the area. Where practical, the design shall include provisions to allow access to different parts of the completed structures for inspection and maintenance. Access hatches with doors, where necessary, should be placed and must be at a minimum 800mm diameter or 800mm square. The design shall ensure ease of maintenance. Structural systems whose maintenance is expected to be difficult should be avoided. Number of deck joints shall be kept to a practical minimum. Deck joints and bearings shall be replaceable. The location of jacking points and area of jack for replacing the bearings shall be provided. The design shall consider a value of 10mm (minimum) for lifting of deck due to replacement of bearings. At the time of bearing replacement, the live load condition shall be specified and considered in the design. Bearing cover where necessary shall be provided. Materials and execution of works shall be according to the latest ADM Standard Specifications. Version 2.0 Part 3 – Section 100 Page 7 of 13 November 2014 ROADWAY DESIGN MANUAL For Road Safety requirements, refer to the latest version of the ADM “Road Safety Guidelines”. For any items not covered in these standards, the consultant shall provide the ADM with his own proposal based on relevant international codes and standards for acceptance. 102 DESIGN FEATURES 102.01 GENERAL The general features of design shall be as specified in AASHTO LRFD, except as clarified or modified in this document. 102.02 ROADWAY DETAILS The cross sectional elements such as road details, maximum gradients, shoulders, sidewalks, kerbs, median widths, road markings, road signs, studs, etc., shall be in accordance Part 2 – Roadway Design of this Manual, AASHTO LRFD (Clause 2.3.2.2.3) and the Urban Street Design Manual (USDM) published by the Abu Dhabi Urban Planning Council (UPC). 102.03 CLEARANCE TO STRUCTURES The vertical clearance to structures shall be in accordance with Part 2 – Section 305, Horizontal and Vertical Clearances. The minimum design vertical clearance shall be 6.0m for all structures associated with roadways, except for pedestrian underpasses which require a clearance of 3.5m. Certain routes may require larger vertical clearances and these will be identified by ADM during the Concept Design stage. In the case of channel crossings, the Consultant shall propose the minimum overhead clearance and navigable width for structures, taking into account the requirements of the relevant agencies. Lesser vertical clearances are permissible only under very restrictive conditions, upon individual analysis and with the approval of ADM. Warning signs and height restriction gantries are required to divert vehicles with loads higher than the minimum vertical clearance of the structure. 102.04 WIDTH AND SPAN The horizontal clear width of the structure should consider the number of lanes, shoulder, sidewalk and visibility requirements of the project. The number of lanes on bridges and underpasses are generally based on planning studies, taking into consideration the future traffic forecasts, plus any planned public transportation routes such as bus rapid transit, LRT or rail lines, etc. The bridge span for road crossings is generally determined by taking into consideration the future additional lane requirements, as per the appropriate regional planning model. Version 2.0 Part 3 – Section 100 Page 8 of 13 November 2014 ROADWAY DESIGN MANUAL 102.05 TRAFFIC BARRIERS, PARAPETS AND RAILINGS Traffic barriers, parapets and railings shall comply with the requirements of Section 13 of AASHTO LRFD, and be subject to the findings of ADM Road Safety Audits. In general, concrete barriers should be used for vehicular containment. For situations requiring a different type, only FHWA crash test approved bridge rails are allowable alternatives. The design shall consider the structural and aesthetical aspects of such barriers and require approval from ADM at the Concept Design stage. Traffic barriers for new structures shall generally be as per Test Level 4 (TL-4) design criteria. For roadways with large volumes of truck traffic, TL-5 or TL-6 guard rails may be required. Selection of the appropriate test level shall be agreed with ADM. See Part 2 – Section 300, Geometric Cross Sections, for further information on barrier test levels. The design of barriers on bridges crossing over railways, waterways, etc., shall comply with the requirements of the relevant authorities. Bicycle railings on a bridge or bridge approach, where high-speed high-angle impacts with a railing or barrier are more likely to occur (such as short radius curves with restricted sight distance or at the end of a long descending grade) or in locations with site-specific safety concerns, shall be 1.4m high. Otherwise, 1.2m may be considered. 102.06 CONCRETE BARRIER TRANSITIONS Transitions from bridge barrier to approach guardrail should, when practical, not be located on the bridge, approach slab or wing walls. 102.07 APPROACH SLABS The purpose of approach slabs is to minimize settlement by providing a transition between the roadway and the concrete deck. Approach slabs are required between the approach roadway and the abutment of the bridge for all new and widened bridges, unless otherwise specified, covering the entire roadway width including the shoulders, from wing wall to wing wall. The design of an approach slab is dependent on numerous factors which can affect the amount and rate of settlement that occurs. The length of the approach slab of a typical bridge should be 8.0m, supported at one end on the bridge abutment and at the other by a sleeper beam resting on the embankment. The exact length of approach slab shall be determined by the consultant on a case by case basis. The end support is assumed to be a uniform soil reaction with a bearing length that is approximately 0.4 times the length of the approach slab. The structural slab shall be designed in accordance with AASHTO LRFD. Appropriate joint details should be provided on the drawings. Version 2.0 Part 3 – Section 100 Page 9 of 13 November 2014 ROADWAY DESIGN MANUAL 102.08 ANCHOR SLABS When approach roadways are paved with concrete pavement, adequate means should be provided to prevent pavement growth from causing damage to the bridge. Use of a properly designed anchor slab is one method of providing this protection. 102.09 DECK DRAINAGE On grade separated structures, roadway drains should not discharge water on to unprotected embankment slopes or within 5m of the travelled roadway below, nor should drains be located less than 1.5m from the centrelines of abutments or piers. In urban areas, collection of deck drainage in a pipe system may be required, with down drains in or on pier columns discharging into storm water drainage collector systems. Provision of collector drains and associated discharge systems on the approach roadways is preferred to installation on the bridge itself. For bridges with sidewalks, expansion joints shall be turned up at the kerb line to prevent roadway water from entering sidewalk areas. Appropriate means should be taken to ensure that sidewalk drainage does not pond and that the water does not escape around the wing walls and erode embankments. For deck drainage design criteria, refer to the “Roadway Design Manual – Drainage”. 102.10 WING WALLS Wing walls shall extend 1.5m beyond the catch point, where the catch point is defined as the intersection of the fill slope in front of the abutment with the finished approach grade at the outside face of the wing wall. The bottom of the wing walls shall be embedded a minimum of 1.0m into the approach fill at the end of the wing walls. 102.11 LIGHTING Consideration shall be given to special lighting above and below the structure. This lighting shall serve as ornamental lighting for aesthetic purposes, but also to enhance safety. This lighting is in addition to the normal roadway lighting. However, locating highway lighting columns on bridges and structures is to be avoided wherever possible. When located on structures, lighting columns shall have anchorage systems designed in accordance with the AASHTO LRFD. Refer also to the Part 2 - Section 1000, Lighting, of this manual, for roadway lighting criteria. Coordination of all structure lighting with existing and/or planned lighting of connecting and adjacent roads must be considered. Version 2.0 Part 3 – Section 100 Page 10 of 13 November 2014 ROADWAY DESIGN MANUAL Roads and bridges lighting systems, connections, poles, etc., shall be in accordance with ADM Lighting Specifications for Roadway/Parking, Tunnels/Underpasses, Lighting Poles and Public Lighting and coordinated with the concerned authorities. 102.12 BRIDGE DECK ELEVATIONS The Consultant should prepare computer plotted contours at 0.1m intervals at a 1:50 scale and tabulate elevations at 3.0m intervals along the profile grade line, with additional elevation points on each perpendicular (radial), such that the bridge can be completely covered with 0.1m contours. The number of elevation points on each perpendicular must be such that the lowest, or the highest, point is outside the bridge for use by the construction supervision staff to help check the contractor’s geometric layout. 102.13 CONCRETE CRACK CONTROL The cracking of a reinforced concrete member shall be limited so that the durability, serviceability or appearance, are not impaired. Reinforcement shall be provided and spaced to meet the requirement in AASHTO LRFD - Clause 5.7.3.4. Table 100.02 CONCRETE CRACK CONTROL Max Crack Width (mm) ɣe Factor Non-buried structural elements (structures remote from marine environments) 0.30 0.75 Structures in contact with soil Structures in marine environments or over the sea 0.25 0.60 Buried structural elements below water level and for concrete in the water tidal zone 0.21 0.50 Exposure Conditions Consideration needs to be given to the location, environment and workmanship of a given structure. A structure is likely to deteriorate quickly if constructed or designed to lower tolerances and exposed to harsh marine environment. 102.14 EARLY THERMAL CRACKING Cracking can occur during the curing process (early thermal cracking) and after the curing process (surface/structural cracking). Additional considerations should be given in the design to limiting the cracks due to these intrinsic effects, such as early thermal. Structures should be checked for early thermal cracking in accordance with the requirements of the Design Manual for Roads and Bridges BA 24/87 and BD 28/87, Early Thermal Cracking of Concrete. Version 2.0 Part 3 – Section 100 Page 11 of 13 November 2014 ROADWAY DESIGN MANUAL 102.15 CORROSION PROTECTION Due to the adverse corrosive environment, reinforced concrete structures shall use epoxy coated rebar, unless otherwise directed by ADM. Rebar shall be epoxy coated according to the relevant ASTM specifications. However, it should be noted that the performance of epoxy coated steel must be ensured by adopting high quality site controls, as detailed further in the ADM Standard Specifications. 102.16 SPECIAL PROTECTIVE COATING All exposed concrete surfaces and the inside surface of box cells shall be protected by a special protective coating in accordance with the Standard Specifications. The coating shall have the ability to provide in-depth protection of reinforced concrete structures against corrosion associated with the ingress of chloride and sulphate ions, carbon dioxide and other air-borne acid gases. 103 ARCHITECTURAL CONSIDERATIONS Structural elements such as bridge deck, piers, barriers, walls, etc. and their surface treatment have a strong visual impact in any landscape. The size, shape and spacing of the structural components must be visually well proportioned and shaped to enhance the aesthetics of the structure. In urban areas, underpasses spanning a given roadway should have similar treatment to establish continuity. Constructability and maintainability considerations should also be taken into account in the architectural treatment concepts. Decorative and median lighting should be similar on bridges along a given route unless otherwise specified. The Consultant will coordinate with Structural, Architectural and Graphic Designers during the development of basic architectural design parameters. The agreed displays shall be submitted to ADM for review and selection of the desired alternative during the conceptual design phase. The accepted scheme will progress to the preliminary and detailed design phases. 104 SERVICE LIFE The design service life for bridges and underpasses shall not be less than 100 years. A Durability Report is to be submitted as per the submission requirements given in the ADM Consultant Procedure Manual. 105 DEFORMATION Flexural members are designed to have adequate stiffness to limit deflection or any deformations which may adversely affect the strength or serviceability of the structure at service load plus impact. Version 2.0 Part 3 – Section 100 Page 12 of 13 November 2014 ROADWAY DESIGN MANUAL For details of deformation criteria, refer to Clause 2.5.2.6 of AASHTO LRFD. The minimum superstructure depths are specified in Table 2.5.2.6.3-1. For rail structures, the service live load deflection plus deflection due to dynamic effects shall comply with the requirements of the relevant agencies. Camber and profile vertical curvature shall be considered when calculating bridge seat elevations for pre-stressed concrete beam bridges, so that the top of roadway will match the design roadway profile. Version 2.0 Part 3 – Section 100 Page 13 of 13 November 2014 0 Part 0 – Divider November 2014 .ROADWAY DESIGN MANUAL SECTION 200 : DESIGN LOADS Version 2. may be used for dead loads. Refer to Part 2: Section 600 – Structural Pavement Design.1. Clause 3. a density of 25 kN/m3 shall be adopted for the dead load. Clause 3.1. For pre-stressed concrete. All bridges and underpass structures shall be designed to carry an additional dead load (kerb to kerb) of 0.5. 201. Version 2.01 GENERAL Load factors.DESIGN LOADS 201 LOAD TYPES 201. A thickness of 110mm of asphaltic wearing course should be considered on the concrete deck for the purposes of the load calculations.5. appurtenances and actual weight of utilities attached thereto. if present) shall be included in the dead load. In the absence of more precise information. the densities specified in Table 3. resistance factors and load combinations shall be as specified in AASHTO LRFD. Refer to AASHTO LRFD. Refer to AASHTO LRFD. load modifiers.02 DEAD LOADS Dead load shall include the weight of all components of the structure.03 WEARING SURFACE The weight of the wearing surface (and waterproofing and additional protective layer.5. clause 602.ROADWAY DESIGN MANUAL SECTION 200 . 201. except as clarified or modified in this manual.1-1 (AASHTO LRFD).75 kN/m2. The density of concrete is primarily affected by the density of the aggregate. which varies by geological location and increases with concrete compressive strength.02 for further details. and any planned widenings.0 Part 3 – Section 200 Page 1 of 5 November 2014 . 04 VEHICULAR LIVE LOADS The normal design vehicular live load will be AASHTO LRFD HL-93 loading times 1.1 (factored by 1.0 Part 3 – Section 200 Page 2 of 5 November 2014 .ROADWAY DESIGN MANUAL 201. total weight 1.400 KN. and at the direction of ADM.01 HL-93 Vehicle Live Loading AASHTO LRFD 3. Refer to Figure 200. shall be applied without dynamic allowance for the Strength II limit state. lane load and tandem load. Refer to Figure 200. This factor shall be applied to truck. Version 2.6.1.01.2.5) P Loads (permit design live loads) are special vehicular loads that will be applied only to specific structures. type Caltrans P13. A single Permit Vehicle.02. Figure 200. such as interchange ramps.5 (for all limit states including fatigue). 05 FOOTWAY OR PEDESTRIAN LIVE LOAD Sidewalk and pedestrian areas (simultaneously with the vehicular design live load) shall be as per AASHTO LRFD (refer to Clause 3.1.6.1.6.06 WIND LOAD A basic wind speed of 160 kph with a gust factor of 1.ROADWAY DESIGN MANUAL Note: K in the above P13 schematic layout stands for Kip. 1 Kip is approximately equivalent to 4.3 of AASHTO LRFD.448 kN. the ADM may require a wind climate study to define the site specific design Version 2.1 to 3. a non-SI unit of force.14 shall be considered during the design of bridges for service conditions. Figure 200. Where necessary.02 Permit Vehicle (Caltrans P13) The application of design Vehicular Live Loads shall be according to Clauses 3. 201. 201. A wind speed value of 130 kph should be used for temporary conditions during construction periods of up to 1 year.6). although higher values may need to be considered for longer construction programmes.6.0 Part 3 – Section 200 Page 3 of 5 November 2014 .1. in accordance with AASHTO LRFD (Clause 3. 201.11. Clause 3. Refer to AASHTO LRFD.2.3. Clause 3. 201. 201. Lateral earth pressure and a live load surcharge will be considered as per AASHTO LRFD. Version 2. +30ºC and -30ºC) and for steel bridges 70ºC (i.7. Clause 3.04 shall be used in accordance with AASHTO LRFD. 201.e. load surcharges resting on the retained soil and hydrostatic pressure below the ground water table. +40ºC and -30ºC). unless recommended otherwise in the Geotechnical Report. active pressure for unrestrained walls should be calculated using an internal angle of friction of 30ºC. The design temperature range for concrete bridges and other structures shall be 60ºC (i. Clause 3.08 THERMAL FORCES The reference construction temperature shall be considered as +30ºC. Refer to AASHTO LRFD. For backfill compacted in accordance with the Standard Specifications.12. During construction. The applicable temperature gradient is for Zone 1.8. For initial design calculations for metallic bearings. Wind tunnel tests may be used to provide more precise estimates of wind pressures and stability.7. Refer to AASHTO LRFD.12. a frictional coefficient value of 0.10 LATERAL EARTH PRESSURE Structures retaining soil shall be designed for lateral pressure caused by the retained soil.3).13 and 14. Clause 3.0 Part 3 – Section 200 Page 4 of 5 November 2014 .07 FRICTION FORCES Friction forces due to elastomeric bearing pads or TFE surfaces shall be based on the manufacturer’s data for the bearings used. Refer to AASHTO LRFD. The Consultant will provide all available soil information for calculating the lateral soil pressure. the value of the frictional coefficient shall be verified as per the manufacturer’s data.ROADWAY DESIGN MANUAL wind speeds and wind direction based on long-term wind statistics for Abu Dhabi.09 STREAM FORCES Stream forces shall be in accordance with AASHTO LRFD.e. Refer to AASHTO LRFD.6. A minimum differential settlement of 10mm may be used in the design.1.0 Part 3 – Section 200 Page 5 of 5 November 2014 . Clause 3. Version 2.1 should only be used where the maximum groundwater level can be assessed accurately. 201. Acceptance of this approach is subject to the approval of ADM. Clause 3. During construction and backfill operations. The Consultant shall establish design water levels for the design of structures for buoyancy. unless otherwise specified. For the earthquake event. probability. shall be considered in determining the design water level. the coincident traffic load shall be 50% of the design traffic load (i. etc). after converting to AASHTO requirements (return period. If Consultants wish to calculate the seismic force precisely. if the report indicates a predicted value less than this. the ground water elevation may be considered at 1.e. adjacent structures. 201. during construction and in service.14 OTHER LOADS Other loads shall be considered as per AASHTO LRFD.5m over the roof or on the sides of underpasses due to future construction works. otherwise the factor should be assessed by the Consultant An allowance shall be made for possible reduction in average depth of backfill of 0. For preliminary assessment.ROADWAY DESIGN MANUAL 201.12 EARTHQUAKES Seismic design shall be carried out following the general principles set out in AASHTO LRFD for Zone 1. The stability calculations for floatation shall consider all temporary and permanent loading conditions.11 DIFFERENTIAL SETTLEMENT Differential settlement shall be considered in the design when indicated in the Geotechnical Report. Refer to AASHTO LRFD. 201. the elevation of groundwater shall be observed and controlled. The Geotechnical Report shall provide the magnitude of differential settlement to be used in the design.7. in this case the earthquake zone adopted in the analysis shall be as per IBC. However.12.0m below the existing ground level. excluding any benefits from skin friction. 75% standard AASHTO-LRFD).13 BUOYANCY AND HYDROSTATIC PRESSURE A structure subjected to groundwater pressure should be designed to resist floatation. A factor of 1. but not limited to. The calculated total deadweight of the structure and backfill on it shall always exceed the calculated uplift due to buoyancy by a factor of not less than 1. seasonal variations. The effect of factors such as. reference may be made to the seismic charts in the Abu Dhabi International Building Code (IBC). etc. ROADWAY DESIGN MANUAL SECTION 300 : REINFORCED CONCRETE Version 2.0 Part 0 – Divider November 2014 . 5%.ROADWAY DESIGN MANUAL SECTION 300 .  Material Properties Reinforced concrete design criteria should be based on the material properties specified in AASHTO LRFD. unless otherwise directed by ADM: Version 2. The durability parameters shall meet the following minimum requirements: Rapid Chloride Permeability (ASTM C1202 or equivalent) Water Absorption (BS 1881 or equivalent) < 700 Coulombs. Design of structural components shall satisfy the requirements at all appropriate service. pulverized fly ash to BS 3892 or equivalent. except as clarified or modified in this document. 301. strength and extreme event limit states specified in AASHTO LRFD. For use of other types of materials. Where conventional methods of strength of materials are not applicable because of nonlinear strain distribution. This may be achieved by incorporating into the concrete mix appropriate percentages of mineral admixtures such as ground granulated blast furnace slag (ggbs) to ASTM C989 (or equivalent). except where specified otherwise in this document.REINFORCED CONCRETE 301  GENERAL Design Reinforced concrete design criteria shall be as specified in Section 5 of AASHTO LRFD. or silica fume to ASTM C1240 or equivalent in combination with applicable type of cement to ASTM C150 (or equivalent). prior ADM approval is required at the Concept Design Stage. < 1.0 Part 3 – Section 300 Page 1 of 4 November 2014 . and using materials that conform to the ADM Standard Specifications.01 CONCRETE All structural concrete mixes shall be designed for low heat of hydration and high durability. fatigue. Concrete for all structures shall have the following minimum specified compressive cylindrical strength. strut-and-tie models may be used to determine the internal force effects near supports and the points of application of concentrated loads at strength and extreme event limit states. ROADWAY DESIGN MANUAL Table 300. walls. bored piles. Version 2.0 Part 3 – Section 300 Page 2 of 4 November 2014 .02 with earth& ground water 100 mm CONCRETE COVER Structural Element Minimum Concrete Cover (mm) Cast-in-place concrete piles 100 Concrete exposed to sea water and splash zone 100 Concrete of all substructure elements in contact with earth and ground water 100 Concrete of all substructure elements exposed to weather 80 Superstructure cast-in-place concrete exposed to weather 60 Inside faces of post-tensioned concrete boxes 50 Prefabricated superstructure elements. barriers and precast panels 35 455 Cast-in-place reinforced concrete in pier shafts. pre-cast superstructure 301. abutments. inside faces 40 Note: Minimum concrete covers shown above may only be reduced if agreed specifically with ADM.02 concrete in bridge MINIMUM CONCRETE COVERS The following minimum concrete clear cover shall be provided:  Concrete of all substructureTable elements in contact 300.01 CONCRETE COMPRESSIVE STRENGTH Minimum Compressive Cylindrical Strength (MPa) Minimum Compressive Cube Strength 2 (kg/cm ) 45 550 Cast-in-place post-tensioned concrete 40 500 Cast-in-place reinforced concrete in bridge superstructure. outside faces 50 Prefabricated superstructure elements. pile-caps and approach slabs 35 455 Non-reinforced concrete 20 250 Structural Element Pre-stressed. All reinforcing bars shall be straight bars top and bottom. are located on the slab. For the purposes of clarity in principle. as the former does not significantly affect load distribution. simple structures are limited to those defined as Category 0 or 1 structures. the Consultant shall comply with any yield strength limitations specified in AASHTO LRFD.0 Part 3 – Section 300 Page 3 of 4 November 2014 .4 and the ADM “Standard Specifications”. railings and any other attachments such as street lighting poles. unless approved otherwise by ADM. Version 2. alternatives including Type 316L. traffic parapets. Grade 60 (minimum yield strength of 420 MPa) and be fusion bonded epoxy coated conforming to ASTM A775. Grade B500B (minimum yield strength of 500 MPa) or ASTM A615. except as clarified or modified in this document. Refer to AASHTO LRFD. the use of uncoated corrosion-resistant reinforcement may also be proposed for use in aggressive environments.04. etc. Section V-1. Fabrication and handling of epoxy-coated reinforcing steel shall comply with ASTM D3963. the design shall consider the critical loading conditions and force effects transferred from these elements to the slab.03 DESIGN METHODS Structures shall be designed according to the requirements of AASHTO LRFD and shall be analyzed as grillage or Finite Element models. such as buried structural elements exposed to ground water and those in proximity to seawater. Clause 5. paragraph 101. However. subject to the approval of ADM. When traffic barriers. The final selection of steel to be used for reinforced concrete structures is subject to the approval of ADM. In these circumstances. The superstructure of simple bridges may be idealized as a single-spine beam where transverse distortion of a superstructure is small in comparison with the longitudinal deformation.04  REINFORCEMENT Reinforced Concrete Reinforcement for concrete shall be steel complying with BS 4449. in accordance with Part 3 : Section 100 – Design Criteria.ROADWAY DESIGN MANUAL 301. 302 SLAB DESIGN Slabs shall be designed in accordance with the criteria specified in AASHTO LRFD. Grade 60 (minimum yield strength of 420 MPa) or Grade 75 (minimum yield strength of 520 MPa) stainless steel to ASTM A955 and corrosion-resistant steel to ASTM A1035 Grade 100 (690 MPa) (AASHTO MP 18) may be considered. Materials for Concrete Works for further details. However. 301. Version 2. All waterproofing systems are to be approved by ADM. 303 WATERPROOFING Concrete cast below ground level and concrete in contact with the soil is to be protected by a waterproofing system in accordance with the specifications.ROADWAY DESIGN MANUAL Refer to AASHTO LRFD. a waterproofing system shall be considered and evaluated on a case-by-case basis.0 Part 3 – Section 300 Page 4 of 4 November 2014 . extending to within 100mm of the finished ground level. Section 13. For bridge decks. 304 SURFACE FINISH All classes of finish are as defined in the ADM Standard Specifications. ROADWAY DESIGN MANUAL SECTION 400 : PRE-STRESSED AND POST-TENSIONED CONCRETE Version 2.0 Part 0 – Divider November 2014 . Use of the transformed area of bonded reinforcement shall only be used for unusual structures and only when approved. For design purposes. prior approval at the Concept Design Stage is required from ADM. except as clarified or modified in this document. stressing. shall be considered.01 GENERAL  Design Pre-stressed and post-tensioned design criteria shall be as specified in Section 5 of AASHTO LRFD. and to restraints or imposed deformations.  Material Properties Pre-stressed and post-tensioned design should be based on material properties specified in AASHTO LRFD.02 ALLOWABLE STRESSES IN PRE-STRESSED CONCRETE MEMBERS The maximum allowable stresses in concrete shall be in accordance with AASHTO LRFD.02 of this Manual.0 Part 3 – Section 400 Page 1 of 7 November 2014 . Version 2. Expansion and Contraction. except as modified below. Use of 12. the relative humidity shall be taken as 60%. handling. Stress concentration due to pre-stressing or other loads. Pre-stressing steel for precast pre-stressed members and cast-in-place post-tensioned members shall be 15. Section properties shall be based on the gross area of members.24 mm diameter low relaxation seven wire strand to ASTM A416 Grade 270. 401. Clause 301.ROADWAY DESIGN MANUAL SECTION 400 PRE-STRESSED AND POST-TENSIONED CONCRETE 401 DESIGN CRITERIA 401. but also for stresses and deformations for each stage that may be critical during construction. tensile strength 1860 MPa. Web reinforcement for shear shall consist of rebar. except where otherwise specified in this document and on the use of materials that conform to the ADM Standard Specifications.70 mm diameter strand is allowed for precast pre-stressed members. not welded wire fabric. For use of other types of materials.9.4. Low relaxation properties shall comply with AASHTO M203 (ASTM A416 or E328). Structural elements shall not only be designed for the service life of the structure. Expansion and contraction design criteria shall be as specified in Part 3 – Section 600. with a minimum breaking load of 261 kN. yield strength 1670 MPa. The minimum cover for reinforcement shall be as specified in Part 3 – Section 300. transportation and erection. Reinforced Concrete. Clause 5. The effects of the future wearing surface shall be excluded from deflection calculations.125√f’c MPa elsewhere. overstressing the pre-stressing steel above the initial stressing limit for short periods of time to offset seating losses is not permitted. Deflections shall be shown in millimetres at the tenth points. diaphragms and barriers and the effects of long term creep on the composite girders.01 DEFLECTIONS The Release. The Initial Deflection equals the deflection the pre-stressed girder undergoes at the time of erection prior to the diaphragm or deck pours. where f'c is the specified compressive strength of concrete (final) used in design. The Release Deflection includes the dead load of the girder and the release prestressing force (including the effects of elastic shortening).03 ALLOWABLE STRESSES .02 ALLOWABLE STRESSES – PRE-STRESSING STEEL For pre-tensioned members. Refer to AASHTO LRFD. Tensile stress at transfer shall be limited to 0. The tops of the erected girders shall be surveyed in the field prior to placement of the deck forming. 402.ROADWAY DESIGN MANUAL Members that are designed as pre-stressed or post-tensioned shall have zero tension under the Service III limit state for structures in coastal areas and 0. Initial and Final Deflections shall be shown on the drawings. 402. 402 PRECAST PRE-STRESSED CONCRETE 402. Bridge camber profile showing the amount of camber required to counteract the dead load and any superimposed load deflection shall be included. the initial pre-stressing and the effects of creep and shrinkage up to the time of erection. The Release Deflection equals the deflection the pre-stressed girder undergoes at the time of strand release.25√f’c MPa. adjustments will have to be made in the roadway profile or in the girder seat elevations.CONCRETE In calculating the temporary stress in concrete before losses due to creep and shrinkage.3. The Initial Deflection includes the deflection due to the dead load of the girder.0 Part 3 – Section 400 Page 2 of 7 November 2014 . Encroachment into the slab of up to 15mm will be allowed for random occurrences. The time of erection should be assumed to be 60 days after release. If the tops of the erected girder elevations are higher than the finish grade plus camber elevations minus deck slab and buildup thickness.9. the steel relaxation prior to release and the elastic shortening should be included. Clause 5. The Final Deflection equals the deflection due to the dead load of the deck slab. Version 2. 01 GENERAL Pre-stressed I-Girder.9. The value of relative humidity to be used in calculating shrinkage losses. The minimum length of these should be 380mm and 450mm for voided slabs and box beams respectively. 402.9. In the absence of available information. VOIDED SLABS AND BOX BEAMS 403. a relative humidity of 60% should be assumed.04  INTERMEDIATE DIAPHRAGMS I-Girders: A single 300mm thick intermediate diaphragm shall be placed at the mid-span for all spans over 12m. Clause 5. Refer to AASHTO LRFD.ROADWAY DESIGN MANUAL Refer to AASHTO LRFD.section.02 The slab and diaphragm dead load is to be supported by the girders only.03 END BLOCKS End Blocks should be provided with sufficient steel to resist the tensile forces due to the prestressing loads. 403. shall be the value of relative humidity at the bridge site. the variable fcdp (concrete stress at the centre of gravity of the pre-stressing steel) should be calculated using all dead loads except the dead load present at the time the prestressing force is applied. 403. The Girders are to be designed as composite . Clause 5. For skews less than or equal to 10°. 403 PRE-STRESSED I – GIRDERS. A creep factor of 3 should be used when calculating long term deflections. simply-supported beams for Live Load and Impact and all superimposed dead loads. Negative moment reinforcement is to be designed over the intermediate supports considering span continuity and all loads.0 Part 3 – Section 400 Page 3 of 7 November 2014 . Differential shrinkage should be considered in the design when the effects become significant and when approved by ADM. place the diaphragms parallel to Version 2.4. Voided Slab and Box Beam Bridges shall be designed in accordance with Section 5 of AASHTO LRFD.5.04 LOSS OF PRE-STRESS For creep of concrete. I – GIRDER BRIDGES 403. For skews greater than 10º. two ties shall be provided. fluidifying and water reducing agents containing no calcium chloride.07 BARRIERS Barriers shall have a 6mm open joint at the midspan to prevent the barrier from acting as an edge beam and causing long term differential deflection of the exterior beam.0 Part 3 – Section 400 Page 4 of 7 November 2014 .  Voided Slabs: Diaphragms shall be cast within the slab at midspan for spans up to 12m and at third points for spans over 12m.  Box Beams: Diaphragms. located at the third points of the section depth.05 LATERAL TIES One lateral tie shall be provided through each diaphragm located at the mid-depth of the section. 403. However. at the third points for spans from 15m to 22m and at quarter points for spans over 22m. the diaphragms shall be staggered and placed normal to the girders.06 SHEAR KEYS After shear keys have been filled with an approved non-shrink. The 28 days compressive strength of grout shall not be less than the specified compressive strength of the adjacent concrete. 403. Version 2. for 990mm and 1. in lieu of continuous ties.065mm deep box beam sections. when adjacent units are tied in pairs for skewed bridges.02 GROUT For post-tensioned stand ducts. cast within the beam. low-slump mortar. nitrates or other chemicals causing steel corrosion. 403. grout used will be non–shrink grout with a minimum compressive strength of 30 MPa at 7 days and 50 Mpa at 28 days.ROADWAY DESIGN MANUAL the skew. shall be provided at the midspan for spans up to 15m. lateral ties shall be placed and tightened. Grout admixture will be a balanced blend of expanding. 404. 404 POST-TENSIONED BOX GIRDER BRIDGES 404.01 GENERAL Post-tensioned Box Girder Bridges shall be designed in accordance with Section 5 of AASHTO LRFD. 2.4. The ducts shall have grout openings at each end. corrugated galvanized steel or HDPE.3.5 times the initial shortening. The camber shown on the drawings shall be the final long term deflection and shall be parabolic. 404. the friction and anchor set losses Version 2.07 DEFLECTIONS Deflection shall be calculated using dead load including barriers. a shrinkage and creep coefficient of 1.5 shall be used for design of substructure elements with the total movement equal to 1. HDPE ducts for bending radii smaller than 9m is not recommended. Clause 5.3.2. Refer to AASHTO LRFD. Clause 5.05 FLANGE AND WEB THICKNESS .10. 404.6. gross section properties and calculated final losses. Minimum web thickness shall be 300mm (measured normal to girder for sloping exterior webs). 404. interlocked mortar and grout tight.ROADWAY DESIGN MANUAL 404.BOX GIRDERS Minimum top and bottom slab thicknesses shall be 200mm and 150 mm respectively.08 ALLOWABLE STRESSES – PRE-STRESSING STEEL In calculating the stress in the pre-stressing steel after seating. Galvanized steel ducts shall be fabricated of not lighter than 28-gauge steel.06 DIAPHRAGMS Consideration for additional diaphragms should be given to box girders with large skews.14. Refer to AASHTO LRFD. 404. and shall be vented at their high and low points. For superstructure elements. no creep factor should be applied except for long term deflection considerations. Ducts shall be at least 6mm larger than the nominal diameter of the strand or wire bundles and the cross sectional area shall be at least twice that of the net steel area. Diaphragms shall be cast integral with girder webs.04 CREEP AND SHRINKAGE For restrained members in continuous bridges where shortening due to post-tensioning induces moments and shears. Intermediate diaphragms are not necessary for straight cast-in-place concrete box girder bridges. Clause 5. curved boxes and boxes with large depths. Interior webs shall be constructed vertical.0 Part 3 – Section 400 Page 5 of 7 November 2014 .03 DUCTS Ducts for bonded post tensioning strands shall be flexible.3. 404. Refer to AASHTO LRFD. Diaphragms shall be placed parallel to abutments and piers for skews less than or equal to 20º and normal to girders and staggered for skews over 20º.7. 0002 shall therefore be used.9. 404. 404. anchor set and elastic shortening losses should be included. Special consideration shall be given to bridges supported on falsework with large openings where deflections could be harmful to the structure.9.CONCRETE In calculating the temporary stress in the concrete before losses due to creep and shrinkage. the variable fcdp (concrete stress at the centre of gravity of the pre-stressing steel) should be calculated using all dead loads except the dead load present at the time the prestressing force is applied. Clause 5. For post-tensioned members. 404. Refer to AASHTO LRFD. Refer to AASHTO LRFD.7. Refer to AASHTO LRFD. the maximum allowable tension in a pre-compressed tensile zone shall be limited to zero.ROADWAY DESIGN MANUAL only should be included.3. Unless falsework requirements are strengthened or other means taken to ensure the bridge does not form tension cracks prior to tensioning.2 and a friction wobble coefficient “K” of 0.4.30% of the flange area.9.2. Anchor set losses should be based on 6mm set and the humidity assumed as 60%. 404. Clause 5. but the maximum allowable jacking stress for low relaxation strand shall be limited to 0. Clause 5.10 LOSS OF PRE-STRESS Friction losses occurring during jacking and prior to anchoring depend on the system and material used and shall be verified as per the manufacturer’s data. the top layer of temperature and shrinkage and bottom layer of distribution reinforcing may be used.5.5.12 FLANGE REINFORCEMENT Reinforcing in the bottom slab of box girders shall conform to the provisions of AASHTO LRFD. In determining the positive ultimate moment capacity.09 ALLOWABLE STRESSES . based on Table 5.0 Part 3 – Section 400 Page 6 of 7 November 2014 . Clause 5. the longitudinal flange reinforcing may be used. where fpu is the tensile strength of the strand.11 FLEXURAL STRENGTH In determining the negative ultimate moment capacity. A friction coefficient “µ” of 0. the friction.2b-1 of AASHTO LRFD. except that the minimum distributed reinforcing in the bottom flanges parallel to the girders as specified in AASHTO LRFD shall be modified to be 0. overstressing for short periods of time to offset seating and friction losses is permitted.78fpu. Initial calculations during design should be based on the usage of galvanized rigid ducts.3.9. Refer to AASHTO LRFD. Version 2. For creep of concrete. 0 Part 3 – Section 400 Page 7 of 7 November 2014 . Version 2.ROADWAY DESIGN MANUAL Refer to AASHTO LRFD.14. Clause 5.2.5.1. 0 Part 0 – Divider November 2014 .ROADWAY DESIGN MANUAL SECTION 500 : STRUCTURAL STEEL Version 2. G12. Availability of specified steel plates or rolled beams. Version 2. which is not considered to be exhaustive:         Basic bridge geometry. 501. Aesthetic appearance. Detailing and fabrication requirements. including optimization of span arrangements and transverse beam spacing. Tension flanges thicker than 50mm shall be normalized. Durability.1-2003 may also be referred to where necessary. AASHTO/National Steel Bridge Alliance (NSBA) Steel Bridge Collaboration. except as clarified or modified in this document.4. unless otherwise approved by ADM.0 Part 3 – Section 500 Page 1 of 2 November 2014 . including transportation and erection constraints. Selection of the appropriate steel section and grade. Intermediate stiffeners shall be placed only on the inside face of exterior girders. The Consultant should consider the following factors for achieving an efficient and cost effective design.04 CHARPY V-NOTCH IMPACT REQUIREMENTS The Temperature Zone applicable to Abu Dhabi for Charpy V-Notch requirements shall be Zone 1. 501. 501. Cost. The preferred maximum thickness of tension flanges is 50mm.ROADWAY DESIGN MANUAL SECTION 500 .01 GENERAL Structural steel design criteria shall be as specified in Section 6 of AASHTO LRFD. Clause 6. subject to ADM approval.STRUCTURAL STEEL 501 DESIGN CRITERIA 501.02 DESIGN METHODS All design shall be in accordance with the AASHTO LRFD limit states. “Guidelines for Design for Constructability”.03 MATERIALS Materials shall conform to the requirements of AASHTO LRFD with the selection based on stress requirements and overall economy. Refer to AASHTO LRFD. Constructability. Clause 6. All connections except field connections shall be welded.ROADWAY DESIGN MANUAL The number and location of girder shop and field splices shall be determined so as to minimize fabricated and erected cost of the girders.13 for connections and splices. ASTM A325M high strength bolts shall be used for field connections. Version 2.0 Part 3 – Section 500 Page 2 of 2 November 2014 . Refer to AASHTO LRFD. ROADWAY DESIGN MANUAL SECTION 600 : EXPANSION AND CONTRACTION Version 2.0 Part 0 – Divider November 2014 . 0 Part 3 – Section 600 Page 1 of 11 November 2014 . Published movement ratings are usually based on the difference between the maximum and Version 2. horizontal and/or rotational movement. Movement ratings shall be based on temperature variations as measured from the assumed mean temperature. Accommodation of thermal and shortening movements will entail consideration of deck expansion joints. except as modified below: The reference construction temperature shall be considered as +30ºC. The design temperature range for concrete bridges and other structures shall be 60ºC (i.EXPANSION AND CONTRACTION 601 MOVEMENT CRITERIA 601. The joints shall be watertight. The required movement rating is equal to the total anticipated movement (i. Movements shall be calculated in accordance with Section 14 of AASHTO LRFD.01 MOVEMENT RATING The design of movement joints must allow the translation and rotation of the structure at the joint without compromising the riding quality of the pavement surface. The bearings are required to transmit the vertical and lateral loads from the superstructure to the substructure units and to allow for movement in the unrestrained directions. Provisions shall be made in the design of structures to resist induced stresses or to provide for movements resulting from variations in temperature and anticipated shortening due to creep. The calculated movements used in determining the required movement rating shall be as specified in AASHTO LRFD. where applicable. 0ºC to +60ºC) and for steel bridges 70ºC (i. while for concrete structures the effects of shortening due to creep and shrinkage (and pre-stressing where applicable) shall also be added.ROADWAY DESIGN MANUAL SECTION 600 . bearing systems.01 GENERAL The movement rating for joints for steel structures shall be based primarily on the thermal expansion and contraction characteristics of the superstructure. the difference between the widest and the narrowest opening of a joint). restraining devices and the interaction of these three items. 0ºC to +70ºC). maintain and replace.e.e.e. shrinkage and pre-stressing. Restraining devices are required to limit the displacement in the restrained directions. Improper design or construction of any of these devices could adversely affect the operation of the other devices. 602 DECK JOINTS 602. The main purpose of the deck joint is to seal the joint opening to obtain a watertight joint while allowing for vertical. and easy to install. The following features of joints should be shown on the drawings: 1. The type of anchorage system to be used.e. Available types of joints include strip seals. Where joints are generic. 3. 7. including enough detail or explanation to accommodate each of the proprietary systems selected (i. Other factors which should be considered in determining the required movement rating include consideration of the effects of any skew. The method of joint termination at the ends. consideration must be given to the installation width required to install the seal element. 5. In determining the movement rating. without consideration of the required minimum installation width. Possible interference with post-tensioning anchorages. 2. anticipated settlement and rotations due to live loads and dead loads. The following features of joints should be provided in the Particular Specifications: Version 2. Selection of appropriate modular proprietary systems that meet design requirements. 6. Susceptibility of joint to leakage. etc. silicone joint sealants and asphaltic plugs. where appropriate. Physical limitation on size of joints.ROADWAY DESIGN MANUAL minimum openings. they should be detailed on the drawings. Blockout details showing a second pour. Items requiring attention include: 1. Movement rating. 3. elastomeric expansion joints and modular joints. cover plates.0 Part 3 – Section 600 Page 2 of 11 November 2014 . However. Forces applied to the surrounding concrete by the joint. sidewalks and/or medians. Assumed temperature and opening at time of installation with temperature correction factors. Actual horizontal length of joint measured from inside of barrier face to inside of barrier face corrected for skew. The method of running joints through barriers. 4. including blockout dimensions and additional reinforcement required.). Information concerning specific design parameters and installation details of modular joints should be obtained from literature supplied by the manufacturer of the system. 2. by standards and/or covered in the special provisions. 5. Required end treatment in barriers or kerbs. in addition to steel finger joints. 4. 8. modular joints are proprietary and require that the designer specify allowable joint types and styles in the special provisions. It is the responsibility of the Consultant to review the proprietary joint literature and related manufacturer's specifications to ensure that the selected joint types are properly specified and compatible with the design requirements. gland type. the joint style. Bearings are to be provided with a steel base and external load plates to allow for simple exchange of the bearing. These joints are the preferred deck expansion joint system for new bridges.03 ELASTOMERIC EXPANSION JOINTS Elastomeric expansion joints comprise integrally moulded units of neoprene and bonded steel. 602. accommodating movements of up to 125mm. this type of joint is usually only specified for thermal movements in excess of 125mm when other types of joint cannot be used. For modular joints. so arranged as to provide for the movements of the bridge deck with one of the steel components bridging the joint gap and of sufficient strength to carry wheel loads across the joint. 602. bearings must be designed to be Version 2. and the name of a representative manufacturer. A general discussion of joint types follows. silicone joint sealants and asphaltic plugs. 602. where the opening can be adjusted if the ambient temperature at the time of construction is different than the assumed mean temperature. As a result. steel edge beam material. 602. However.0 Part 3 – Section 600 Page 3 of 11 November 2014 . 603 BEARINGS 603. for modular joints the actual selection of the specific alternatives should be made from the list of approved joint types which can be obtained from ADM. All bridge movements are taken entirely by deformation of the neoprene. are expensive and may require significant maintenance. Examples of these are steel finger joints. 2.01 GENERAL The bearings and their supports shall be designed and detailed according to Section 14 of AASHTO LRFD.02 STRIP SEALS Strip seals comprise a neoprene membrane which is rigidly attached to steel restrainers on both sides of the joint and are usually protected by a steel cover plate. Unlike joints. This type of joint can accommodate relatively large movements.05 OTHER JOINTS Other types of joint may be considered depending on the required application.04 MODULAR JOINTS Modular joints are very complex joint systems. Method of measurement (by linear metre from face to face of barrier).ROADWAY DESIGN MANUAL 1.  Durometer Hardness. sliding elastomeric bearings and high-load multi-rotational bearings (pot. both the elastic and long term pre-stress shortening effects shall be considered. steel bearings. In the case of cast-inplace post-tensioned concrete box girder bridges. 603. long term creep and shrinkage and temperature is greater than 40mm.03 ELASTOMERIC BEARING PADS Elastomeric bearing pads shall conform to the requirements of AASHTO LRFD. An initial offset of the top sliding surface from the centreline of bearing should be calculated and shown on the plans. Sliding elastomeric bearings are both generic and proprietary in that a generic bearing should be designed and detailed on the drawings with proprietary alternatives allowed.02 NEOPRENE STRIPS Neoprene strips consist of a sliding plate on a continuous neoprene pad. where initial shortening due to pre-stressing is greater than 25mm and where the movement rating including elastic shortening. creep and post-tensioning shortening has taken place in the superstructure.0 Part 3 – Section 600 Page 4 of 11 November 2014 . Movement ratings shall be calculated precisely. so that the top sliding surface will be centred over the bottom sliding surface and the centreline of bearing after all shrinkage. For this reason. Version 2. elastomeric bearing pads. Neoprene strips. the movement rating should be based on the full temperature range and not the rise or fall from a mean temperature. skews greater than 20º. The following data should be shown on the drawings:  Length. However. elastomeric bearing pads and steel bearings are generic and shall be detailed on the plans and/or covered in the Standard Specifications and special provisions. with the controlling case determining the size. High-load multirotational bearings are proprietary bearing types and require the Consultant to include a Bearing Schedule on the drawings. All bearings types except elastomeric bearing pads shall be designed for impact. disc or spherical). Width and Thickness of Pad. Bearing pads shall be designed to be constructed using either steel or fiberglass laminates.  Design Method (A or B). where applicable. It is the responsibility of the Consultant to review the Standard Specifications to ensure that the bearings are properly described and compatible with the design requirements. 603. shrinkage and pre-stressed shortening.ROADWAY DESIGN MANUAL installed at temperatures other than the mean temperature. Calculation of the movement rating shall include thermal movement and anticipated shortening due to creep. Permissible bearing types include neoprene strips. contributing spans greater than 50m. neoprene strips are not appropriate for the following applications: curved bridges. such as in older style sliding steel plate joints or widenings where existing steel bearings are to remain.05 SLIDING ELASTOMERIC BEARINGS Sliding elastomeric bearings consist of an upper steel bearing plate anchored to the superstructure. The bearing accommodates horizontal movement through the teflon sliding Version 2. a stainless steel undersurface and an elastomeric pad with a teflon coated upper surface.Elastomer with steel reinforcement. bearing pads shall be Durometer 60 . Section 14. When used with prestressed I-girders.04 STEEL BEARINGS Steel bearings may consist of rockers or fixed or expansion assemblies which conform to the requirements specified in AASHTO LRFD. However. The use of elastomeric bearing pads should generally be limited to a thickness not greater than 100mm. precast prestressed girders and post-tensioned box girder bridges where neoprene strips are not appropriate. based on Low Temperature Zone A as defined in AASHTO LRFD. Normally Design Method A will be used in design. 603. Pads shall have a minimum thickness of 25mm and be designated in 10mm increments.0 Part 3 – Section 600 Page 5 of 11 November 2014 . Note that the Elastomer Grade should be 0. Width and length dimensions shall be detailed in even 50mm increments. Generally.ROADWAY DESIGN MANUAL  Design Load. Steel bearings are not a preferred bearing type and their use should normally be limited to situations where new bearings are to match the existing bearing type on bridge widening projects. Where elastomeric bearing pads with greased sliding plates are used on post-tensioned box girder bridges to limit the required thickness of the pad. where only steel reinforced pads will work. with the initial and long term shortening assumed to be taken by the sliding surface. Elastomeric bearing pads are the preferred bearing type for new steel girders. The teflon surface shall be attached to a 10mm minimum thick plate which is vulcanized to the elastomeric pad. 603. Holes will not be allowed in the pads.  Shear Modulus. Design Method B may be used provided the special testing is performed. Elastomeric pads should not be used in cases where deck joints or bearings limit vertical movements. pads shall be sized a minimum width of 50mm less than the nominal width of the girder base to accommodate the 20mm side chamfer and shall be set back 50mm from the end of the girder to avoid spalling of the girder ends. the pad thickness should be determined based on temperature movements only. sliding surfaces to accommodate translation. Sliding elastomeric bearings should be considered for applications where regular elastomeric bearing pads would exceed 100mm in height or where special access details would be required for other proprietary bearings in such places as hinges.06.0 Part 3 – Section 600 Page 6 of 11 November 2014 . Rc = Rotation induced in the bearing by construction tolerances.06 HIGH-LOAD MULTI-ROTATIONAL BEARINGS 603. The special provisions should allow for proprietary alternatives. Therefore. with a flat upper surface. Vertical restraint may be provided by anchor bolts with slotted keeper plates or individual vertical restrainers as appropriate. in special cases where structural requirements fall outside the normal limits. and guide bars to limit movement in specified directions when required.ROADWAY DESIGN MANUAL surface and rotation through the elastomeric bearing. a bearing manufacturer should be consulted.06. are determined by: Rb = Rs + Rc where: Rb = Rotation capacity designed into the bearing. forces and movements. 0. Pot bearings consist of a rotational element comprised of an elastomeric disc totally confined within a steel cylinder. 603. The design and manufacture of multi-rotational bearings relies heavily on the principles of engineering mechanics and extensive practical experience in bearing design and manufacture. Rb. Keepers may be used for horizontal restraint of the pads. Spherical bearings consist of a rotational element comprised of a spherical bottom convex plate and mating spherical top concave plate. 603.02 Rotational Requirements The rotational requirements of the bearings.04). These design criteria were prepared for the broad range of normal applications and the specified limits of loads.01 Description High-load multi-rotational expansion bearings consist of a rotational element of the Pot-type.02 radians maximum (see Design Criteria Item 14 in Clause 603. Version 2. with the thickness of the elastomeric bearing determined by the rotational and friction force requirements. Disc bearings consist of a rotational element comprised of a polyetherurethane disc confined by upper and lower steel bearing plates and restricted from horizontal movement by limiting rings and a shear restriction mechanism. Rs = Anticipated rotation of the structure in service (includes live loads and rotations induced by construction/erection sequences).06. The pad dimensions and all details of the anchorage and restraint systems shall be shown on the drawings. Disc-type or Spherical-type. 03 Use Use of multi-rotational bearings is especially indicated where: 1. Where feasible. each able to resist all horizontal forces at each abutment. 5. Some press-fit guide bar details in common use have proven unsatisfactory in resisting horizontal loads. 4. repair or replacement of the bearings. Vertical and horizontal loads shall be assumed to occur simultaneously. long life or low maintenance bearings are desirable. column.0 Part 3 – Section 600 Page 7 of 11 November 2014 .04 Design Criteria Since special details are required to allow for access for inspection. The direction of rotation varies. Settlement of the substructure is anticipated. consideration should be given to the Version 2. Self aligning capabilities are required. Minimum vertical loads are dead loads and superimposed dead loads. 603. 5. 7.ROADWAY DESIGN MANUAL 603. Avoid specifying total spacing of more than 1. 10. live loads and impact. hinge or pier. Long span. 9. column. Low profile. 6. The direction of rotation cannot be precisely determined. provide at least two fixed or guided expansion bearings. 12. Economical.06.5mm between guides and guided components where possible. When analyzing these designs. 6. it is recommended only one fixed or guided expansion bearing shall be assumed to resist the sum of all the horizontal forces at each abutment. Some structural considerations in the use of multi-rotational bearings are listed below: 1. All loads are service loads. 3. high load bearings are required. the re-spacing of joints to eliminate the need for use of these bearing types should be considered. 8. Regular elastomeric bearing pads would exceed 100mm in height. The total recommended clearance between all guiding and guided sliding surfaces is 1. Large movements are anticipated.06. hinge or pier for design redundancy. Long slender columns or light frames and members exhibit minimum stiffness or rigidity. Maximum vertical loads are dead loads. in order to limit edge stress on guiding interfaces. 4. It is desirable to reduce the moment applied to truss or space frame panels.5mm. 2. curved or skewed bridges and other similar structures of complex design are required. Load and rotation eccentricity does not significantly alter the net distribution of stress through the bearing and into the substructure and superstructure. 3. 2. In specifying the horizontal force capacity of bearings. 11. Tender drawings and documents should contain a Bearing Schedule (see Clause 603.000 kg. Rs comprises live loads and rotations induced by construction/erection sequences. The differing deflection and rotation characteristics may result in damage to the bearings and/or structure. Some bearing tests are very costly to perform.07). The Consultant may elect to specify a smaller Rc than 0. The following test requirements should be carefully considered before specifying them: Version 2.08 The above coefficients of friction are based on the average stress and limits of edge stress of PTFE. 13. Part 3 – Section 600 Page 8 of 11 November 2014 .30) is anticipated. will require special assessment of the long term coefficient of friction. is 0. Bearings for less than 20% vertical capacity require special design. The substructure and superstructure should be designed so as to remain rigid under all service conditions in areas around and in contact with the bearings. Multi-rotational bearings should not be used at vertical loads less than 20% of their vertical capacity.02 radians but is cautioned to investigate the cost and practicality of the changes contemplated. where exceptional corrosion of the stainless steel mating surface may occur. paying particular attention to the use of stiffeners at extreme points of movements. 11. the rotation induced by construction tolerances. 18.ROADWAY DESIGN MANUAL possibility of rolling of the bar in the recess. Jacking points shall be provided in the structural design. Other bearing tests cannot be performed because of the unavailability of test equipment. 7. Special studies or designs may be required on curved or skewed structures to ensure correct installation. Service conditions.  Horizontal loads exceeding 225.04  Filled PTFE sheet/stainless steel : 0. out-of-level installations and normal in-service oxidation of the stainless steel mating surface. The installed alignment of bearing guiding systems relative to the anticipated movement direction of the structure should be carefully considered to avoid bearing guide system failure. 17. 15.000 kg. Frictional resistance of bearing slide surfaces should be neglected when calculating horizontal load capacity. The maximum Construction Rotation (Rc).01 radians. The minimum Structure Rotational (Rs) of bearings is 0. Pot.0  Vertical loads exceeding 2. 8. disc and spherical multi-rotational bearings should not be mixed at the same expansion joint. 10. The substructure and superstructure design should permit bearings to be removed for inspection or rehabilitation by minimum jacking of the structure. 16. Special consideration in bearing design shall be given where high horizontal to vertical load (above 0. 9.250. 14. Recommended coefficients of friction for structure design are as follows:  Unfilled sheet or woven fiber PTFE/stainless steel : 0. 12.02 radians. 2. Fixing or anchorage details and/or requirements. A schedule of all minimum and maximum vertical and horizontal service loads.  Triaxial test loading. 7.4. movement and other requirements in the Bearing Schedule should only refer to the requirements of the structure where the bearings are to be used. Grades. Design rotation. 11. Uplift details. Restraining devices shall be designed to resist the imposed loads including earthquake as specified in AASHTO Version 2. in accordance with the typical schedule provided in Figure C14. alignment direction of movement. restraining devices shall be designed and provided as specified in AASHTO LRFD. if any. Note that the following information should be provided. bevels and slopes of all bearings.ROADWAY DESIGN MANUAL 603. 604 RESTRAINING DEVICES 604. Magnitude and direction of movements at all bearing support points. if required. 13. 3. 9. 12. 4. as a minimum: 1. 10. 6.0 Part 3 – Section 600 Page 9 of 11 November 2014 . Allowable coefficient of friction of slide surfaces.07  The simultaneous application of horizontal and vertical loads. 8. Installation scheme. 5. Minimum structure and construction rotation requirements. Quantity. Seismic requirements. Restraining devices are meant to prohibit movement in a specified direction. Bearing preset details. point of zero movement and location of all bearing units. Plan view. where the horizontal loads exceed 75% of the vertical loads. BEARING SCHEDULE A bearing schedule shall be included on the tender drawings and documents. Allowable upper and lower bearing contact pressure. expansion or guided expansion). 14.01 GENERAL Where necessary.  The requirement for dynamic rotation of the test bearing while under vertical load. type (fixed. temporary attachments or other requirements. Surface coating requirements and the appropriate specifications.1-1 of the AASHTO LRFD. Allowable restraining devices include. Version 2.02 VERTICAL FIXED RESTRAINERS Vertical fixed restrainers consist of cable and appropriate hardware and are designed to allow rotation but no translation in either horizontal or vertical directions. Restraining devices could include concrete shear keys or end blocks. Restraining devices to prohibit vertical displacement at expansion ends shall be designed to allow for inspection and future replacement of bearings. 604.ROADWAY DESIGN MANUAL LRFD and as modified in Section 200 of this Manual. but are not limited to the following:  Vertical Fixed Restrainers  Vertical Expansion Restrainers  External Shear Keys  Internal Shear Keys  Keyed Hinges.05 INTERNAL SHEAR KEYS Internal shear keys are reinforced concrete blocks designed to limit transverse displacement while allowing longitudinal and rotational movements. horizontal or vertical cable restrainers or mechanical restraining devices which could be an integral part of a bearing or a separate system. 604. Some limited vertical displacement is allowed to permit replacement of bearings if required.0 Part 3 – Section 600 Page 10 of 11 November 2014 . 604. External shear keys are preferred to internal shear keys since they are more accessible for repairs and easier to construct.06 KEYED HINGES A keyed hinge is a restraining device which limits displacements in both horizontal directions while allowing rotation. 604.03 VERTICAL EXPANSION RESTRAINERS Vertical expansion restrainers consist of cable and appropriate hardware and are designed to allow rotation and longitudinal translation but no transverse translation.04 EXTERNAL SHEAR KEYS External shear keys are reinforced concrete blocks designed to limit transverse displacement while allowing longitudinal and rotational movements. Restraining devices for different typical applications are provided below: Expansion Seat Abutments Vertical expansion restrainers and external shear keys (if restraining devices are required). 604. Expansion Piers Vertical expansion restrainers and internal shear keys.ROADWAY DESIGN MANUAL Pinned Seat Abutments (Post-Tensioned Box Girder Bridges) Vertical fixed restrainers and external shear keys. Version 2. Pinned Seat Abutments (Prestressed Girder Bridges) Vertical fixed restrainers and external or internal shear keys.0 Part 3 – Section 600 Page 11 of 11 November 2014 . Pinned Piers Vertical fixed restrainers and internal shear keys or a keyed hinge. 0 Part 0 – Divider November 2014 .ROADWAY DESIGN MANUAL SECTION 700 : GEOTECHNICAL Version 2. The initial phase consists of preliminary drilling and testing to gather enough project-specific information to advance the roadway and structure design. if required. the Consultant prepares a preliminary subsurface exploration and testing program. the geotechnical investigation shall be performed to the satisfaction of ADM. as well as identifying the type.02 GEOTECHNICAL REPORTING Once the preliminary horizontal and vertical alignment and structure locations have been defined. Generally a geotechnical investigation is carried out in two phases. The Consultant shall obtain approval from ADM. The scope and format of the subsurface explorations and testing program is described in the ADM document entitled “Guidelines for Geotechnical Investigation”. The geotechnical report is to contain the information shown in Table 700.01 GENERAL ADM regulations require a geotechnical study to be prepared and submitted to the ADM’s Geotechnical Specialist for review and acceptance. such as foundation types. severity and extent of any geotechnical design problems. 701. Standard SI practices and the ADM “Guidelines for Geotechnical Investigation” (current revision) should be used for guidance. sampling or analysis required. safe slope angles and preliminary pavement design. Pavement design procedures are included in Part 2 – Section 600. The findings of this investigation will be used to provide design information. 701. due to the variability of ground conditions and the various risks involved. the Traffic Police and any other concerned Agencies prior to commencing a geotechnical investigation. The pavement design is the duty of the Consultant’s Pavement Engineer.0 Part 3 – Section 700 Page 1 of 7 November 2014 . Prior investigations and data may be obtained from the data base of the Spatial Data Directorate of UPD. as a minimum: Version 2. However. It does not cover the specific methods of testing. The road pavement design for the project will be based on the findings of this study. is performed for design features requiring specific geotechnical recommendations.01 below.ROADWAY DESIGN MANUAL SECTION 700 – GEOTECHNICAL 701 GROUND INVESTIGATION FOR GEOTECHNICAL WORKS This Section gives an overview of the requirements of a geotechnical report used for roadway and structural design. as well as any information from prior investigations. The final stage. The geotechnical report should consist of results and recommendations from the initial drilling and testing program. as well as their group behaviour in both vertical and lateral directions. their geotechnical capacity and their settlement computations. Part 3 – Section 700 Page 2 of 7 November 2014 . etc) Summary of the Geotechnical Engineering Report  Ground and groundwater conditions including possible groundwater flow problems  Climate  Significant geotechnical features  Regional geology and seismicity and the relevant maps  Risk Identification and History of Geotechnical Problems  Design and Recommendations  Earthworks structure a) Cutting slopes b) Embankment stability c) Re-use of material  Highways structures (details of each highway structure type)  Reinforced soil slopes and embankments  Drainage and groundwater control measures  Pavement design.0 Trial Pits and borehole location plan (historical and new) including in-situ testing locations (CPT. PLT.01 GEOTECHNICAL ENGINEERING REPORT TABLE OF CONTENTS  Introduction  Site Description and Site Location Plan  Proposed Construction  Previous Information and/or Investigations (source of information and desk study)  Field Study and Laboratory Testing   Version 2. subgrade and foundation (refer to pavement design requirements)  Assessment of potential contamination  Ground and groundwater chemistry for buried structures  Topsoil and planting requirements  Ground treatment and ground improvement  Selection of type of foundations.ROADWAY DESIGN MANUAL Table 700. 01 (Continued) GEOTECHNICAL ENGINEERING REPORT TABLE OF CONTENTS  Instrumentation and Monitoring (during construction)  Other Relevant Aspects  (any aspects affecting future performance of the Works) Appendices  Exploratory hole logs  Summary of test results  Geological sections  Other pertinent information Pertinent information should be included in the Appendices. The usual procedure for designing bridge foundation substructure units is as follows: The Bridge Design Team will develop a preliminary location plan. 702 GEOTECHNICAL DESIGN 702.01 FOUNDATIONS 702.01. The Geotechnical Report will include a Foundation Design Report which identifies the type of foundation recommended for each substructure unit including the allowable Version 2. drill and log borings. identify borehole locations. another purpose of this section is to define the role of the Geotechnical Engineer and the Bridge Engineer in design problems involving both fields. The Contractor should employ a Geotechnical Engineer to review.01 General The main purpose of this section is to document bridge design criteria as related to bridge foundation geotechnical issues. such as a major bridge design or other major structure. It is recommended that the Geotechnical Engineer has a minimum experience of 15 years in the field of geotechnical engineering design.0 Part 3 – Section 700 Page 3 of 7 November 2014 . plot the boring logs and summarize the results in a Geotechnical Report. The Geotechnical Engineer will conduct a site investigation. Since problems requiring geotechnical and structural expertise often result in confusion concerning the responsibilities of each.ROADWAY DESIGN MANUAL Table 700. In certain circumstances. approve and certify the geotechnical report prior to submitting it to the ADM’s Geotechnical Specialist for acceptance. perform soil testing as appropriate. an additional report may be required to define special geotechnical aspects of foundation design. These proposals are subject to the approval of ADM. required foundation depths. For foundation units situated in an Version 2. such as stages during construction and possible future repair works. ground water control and predicted ground movements. Allowable bearing pressure for soil or rock and other soil parameters for design shall be provided by the Geotechnical Investigation Report and adopted in the analysis and design in consultation with the Consultant’s Geotechnical Engineer. For foundations supported on groups of piles. In exceptional cases where spread (strip) footings may not be feasible. The simulation shall consider all feasible scenarios.02 Design of Foundations Foundation design shall be in accordance with the latest revision of AASHTO LRFD and the limit states of design specified in Section 10. However. The Bridge Design Team is responsible for producing the structural design and construction documents for the substructure and foundation as part of the bridge plans. piled foundations may be used subject to approval by ADM. pile settlement requirements. The Geotechnical Engineer is responsible for preparing the boring logs on construction plans and for preparing necessary special provisions for construction of the foundation elements. and drilled shaft construction. simplified methods such as those based on the Winkler model.01. The Consultant shall select an appropriate method of simulating soil-structure interaction. vertical and inclined underground structural walls.03 Spread (Strip) Footings Where good soil materials exist near the surface.ROADWAY DESIGN MANUAL loads. given the complexity of the system for all foundation designs. can be used. 702.5 of AASHTO LRFD.0 Part 3 – Section 700 Page 4 of 7 November 2014 . pile group analysis under different combinations of actions shall be performed. 702. the Geotechnical Engineer oversees geotechnical testing. shallow foundations in the form of spread (strip) footings will normally be the recommended foundation type.01. or its derivatives. spread footing excavations and piling. pile geotechnical capacity. including that for piled and shallow foundations. If deemed appropriate. including selection of a constitutive model suitable for the soil material on site. more complex situations may warrant the use of other methods such as continuum analysis. and combined systems of two or more of them. An experienced Geotechnical and Structural Engineer will need to propose and to justify the use of a particular type of analysis. They work closely with the Bridge Design Team to jointly resolve problems arising from unforeseen ground conditions. During construction of the foundations. Spread (strip) footings shall be used for all retaining walls. lighting columns. the use of vibrocompaction. differential settlement and time rate of settlement. immediate load carrying capacity. AASTHO LRFD does not provide design guidance for such piling techniques. If the possibility for differential settlement is identified. and a sustainable and environmentally friendly foundation. when settlement is a problem. including but not exclusive to.ROADWAY DESIGN MANUAL active stream where scour is a potential risk. gantries. minor highway structures and CCTV. The corrosion rate of 0. the minimum top cover over the top of footings shall be 500mm (refer to BS 8002:1994. the Consultant shall confirm the suitability of this method with respect to the particular conditions in Abu Dhabi. These piles may be suitable for a number of highway structures including road signs. Driven piles may be steel H piles. The Geotechnical Engineer may propose the use of ground treatment methods to enhance soil resistance to settlement. gantries and platform foundations. One type of deep foundation is a driven pile. Consideration should be given to ground and groundwater conditions to ensure durability of the piles during the design life of the structure. steel pipe piles or pre-stressed concrete piles. but it should follow up-to-date international design guidance on design of helical piles. 702. Spread (strip) footings are normally not placed on embankment material. material specifications and construction methodology shall be submitted to ADM for review and approval. but the Contractor should provide for approval his assessment and any proposed protection measures in relation to Version 2. such as climatic conditions and construction practices. vibro-stone columns and soil replacement. which specifies that this is the minimum depth for unplanned excavation). Such measures may include. It shall also contain the overall stability check. the elevation of the bottom of the footing and the estimated total settlement.04 Pile Foundations When good foundation material is not located near the surface. For a number of highways structures. the use of Helical Piles may be considered. If the use of this piling technique is proposed.075 mm/year given in BS EN 1993-5 for a splash zone within marine environment is provided for guidance. spread (strip) footings shall only be used when they can be placed on non-erodible rock. or for foundation units located in streams where scour is a problem. The Bridge Design Team shall size the footing to ensure that the allowable bearing pressure is not exceeded for applicable AASHTO LRFD load combinations and that the footing is properly sized and reinforced to resist the maximum applied moments and shears.0 Part 3 – Section 700 Page 5 of 7 November 2014 . and the requirements of the particular project being considered. Helical piles can offer speed of construction. the Consultant shall ensure that the entire structure is capable of structurally resisting the forces induced by the differential settlement.01. the Geotechnical Report shall contain the allowable bearing pressure. The other type of deep foundation is the bored pile. Details concerning the proposed design. The bottom elevations of spread (strip) footings shall be set at the recommended depth. if applicable. deep foundations will usually be recommended. For highways retaining structures. Bored piles are the most common type of concrete pile used in Abu Dhabi. When spread (strip) footings are the recommended foundation type. but not be limited to. Consideration should be given to the limitation on length of reinforcing cage that can be installed with this piling technique.0 Part 3 – Section 700 Page 6 of 7 November 2014 . The use of the Continuous Flight Augur (CFA) piling technique may eliminate the need for the use of casing.01. The construction drawings may specify the need for a permanent casing. The Contractor should demonstrate that his working methodology can ensure that reinforcing cage can be practically installed. most particular within the water fluctuation zone. The Geotechnical Engineer is responsible for recommending the minimum diameter of bored pile to be used.ROADWAY DESIGN MANUAL corrosion and methods of dealing with it. the estimated pile tip elevation and any special requirements necessary to drive the piles. The pile group analysis should be conducted by an experienced Geotechnical Engineer using appropriate soil-structure interaction methods to determine pile loading. The Geotechnical Engineer is also responsible for establishing the pile driving criterion using the FHWA Gates Formula and confirmed by running the GRL WEAP wave equation computer program to determine the drive-ability of the specified piles and to develop charts or other guidelines to be used by construction personnel to control the pile driving process. Version 2. The temporary casing will be advanced to a sufficient depth into soil or rock to provide a seal against water inflow during the construction process of the pile. typically up to 12m below pile cut-off level. as well as bending and shear capacity. The Bridge Design Team is responsible for ensuring that the allowable axial capacity is not exceeded for applicable AASHTO LRFD load combinations and that the pile can withstand the applied axial and lateral loads.06 Bored Piles A conventional bored pile foundation generally consists of excavating a round hole by machine. the type of driven pile to be used. When steel piles are used.01. the corrosive life of the pile will be reported in the Geotechnical Report. the allowable axial geotechnical capacity in compression and tension. The Geotechnical Engineer is also responsible for determining the soil properties in each layer to be used in analyzing lateral loads and whether slurry methods of construction may be utilized. This piling technique (CFA) is likely to be appropriate for most ground conditions including soft rock. conventional bored piles will require a temporary casing or liner intended to preclude the intrusion of earth into the hole during the boring operation.05 Driven Piles The Geotechnical Engineer is responsible for recommending when driven piles are to be used. 702. placing a reinforcing cage in the casing or liner and then filling the casing or liner with concrete. In unstable ground. installing a metal casing or liner. The Geotechnical Engineer shall check the geotechnical capacity under the combination of loadings provided by the Structural (Bridge) Engineer. for evaluating the geotechnical axial capacity of the pile and for determining the minimum required embedment below a specified elevation to develop the required axial load. 702. Methods of testing the pile after concreting will be specified in the Geotechnical Report and in the project specifications. this will be advanced inside the temporary casing prior to the installation of reinforcing cage and placement of concrete. The pile cap. Clause 10. 2. applicable concrete and surrounding soil pressures.ROADWAY DESIGN MANUAL The Bridge Design Team is responsible for ensuring that the allowable axial capacity is not exceeded for applicable AASHTO LRFD load combinations and that the pile can withstand the applied lateral loads. driving and retraction stresses. 3. Temporary and permanent casings or liners shall be designed to withstand handling. if applicable. and shall be watertight. the following minimum criteria should be used in designing bored pile foundations: 1. The bridge design team will provide details of the reinforcement requirements for each pile including cover to reinforcement. Version 2.0 Part 3 – Section 700 Page 7 of 7 November 2014 .9. shall be sized to extend a minimum of 200mm from the edge of a bored pile.1.07 Micropiles Micropiles are classified into a number of categories depending on the method of installation. Reinforcement shall have cover in accordance with the requirements of Clause 301. 702. Unless specified otherwise in the Geotechnical Report. Details of these categories and the typical areas where Micropiles should be considered are summarized in AASHTO LRFD.02.01. 0 Part 0 – Divider November 2014 .ROADWAY DESIGN MANUAL SECTION 800 : RETAINING WALLS Version 2. structural requirements and site constraints. Retaining walls may be gravity walls.RETAINING WALLS 801 DESIGN CRITERIA 801. The overall shear stability of the retaining wall shall be evaluated using the limiting equilibrium method of analysis. The wall selection process shall determine the appropriate type of wall for the site.0 should also be adopted for sliding.0 should be used in the design.0 Part 3 – Section 800 Page 1 of 4 November 2014 .5 against sliding and 2. cantilever walls. The safety factor for footing bearing capacity of 3. unless higher values are deemed appropriate by the Consultant. Version 2.01 GENERAL All design shall follow the procedures as outlined in Section 11 of AASHTO LRFD. the factor of safety of 2. Where soil geotechnical parameters are not well defined. etc. The following Factors of Safety are acceptable for short term conditions. Walls may be classified in the following classes: Gravity Walls:  Bin  Crib  Wire Basket  Mass Concrete Cantilever Walls:  Concrete Braced Walls:  Anchored Walls  Soldier Pile and Lagging  Tangent Cylinder Piles Mechanically Stabilized Walls:  Reinforced Earth  VSL Retained Earth  Hilfiker-Reinforced Soil Embankment Walls shall be checked for a minimum factor of safety of 1.0 against overturning.ROADWAY DESIGN MANUAL SECTION 800 . braced walls. except as clarified or modified in this document. Considerations should be given to in-situ ground and groundwater conditions. mechanically stabilized walls. ROADWAY DESIGN MANUAL  Factor of safety of 1. In calculating the relevant Factor of Safety. where the geotechnical parameters are based on limited information. The Roadway Design Team is also responsible for identifying the acceptable limit of excavation required to maintain traffic and to design any detours when required.02 TYPE OF STRUCTURE The Consultant should study alternative feasible options for the appropriate retaining wall type based on site conditions and include these in the Bridges and Highway Structures Concept Report. future use  Deflection tolerance  Ease of construction  Environmental/visual considerations  Special loading requirements  Settlement tolerance  Availability of space  Ground and groundwater conditions 801. Geotechnical and Bridge.0 Part 3 – Section 800 Page 2 of 4 November 2014 . maintenance. described in Part 1 – Section 300.3. In determining the types of retaining walls capable of fitting a particular site the following should be considered:  Availability of materials  Service life. 801. where the geotechnical parameters are well defined. Design Concept Report. or the slope supports or contains a structural element. the most adverse loading and groundwater conditions should be considered. or the slope does not support or contain a structural element.03 RESPONSIBILITIES The design of a retaining wall will usually involve the efforts of three design teams within the Consultant’s organization: Roadway. 801.5. Version 2. This applies for both temporary and permanent loading.01 Roadway Design Team The Roadway Design Team is responsible for identifying the need for and limits of the retaining walls.03.  Factor of safety of 1. They will be responsible for providing a profile adjacent to the top of the wall and the soil profile line along the front face of the wall. 04. However. Appurtenant traffic and/or pedestrian rails will also be designed and detailed by the Bridge Design Team. for any non-proprietary wall requiring structural analysis. Quality Assurance. The Geotechnical Team is also responsible for determining the type of foundation required to support the wall loads. 801.0 Part 3 – Section 800 Page 3 of 4 November 2014 .ROADWAY DESIGN MANUAL 801. the Contractor shall also be responsible for the design review of the retaining wall. determining the external stability of the site and determining the material properties of the existing soil and backfill. This Team works with the Geotechnical Team on required structural design changes during construction because of changed site conditions. Approvals from ADM for retaining walls with a retained height of 3m and greater will be required prior to implementation of such a system. The Bridge Design Team is also responsible for determining whether shoring will be required during construction based on the acceptable limits of excavation provided by the Roadway Design Team and the safe excavation slopes provided by the Geotechnical Engineers. The contractor will be required to identify the alternative in his tender. This Team determines the soil properties to be used in determining the lateral loads to be applied to the wall and determines the amount of settlement. with bid shopping after the award of the contract not allowed. Version 2.04 PROPRIETARY RETAINING WALLS The contractor may opt to use a proprietary retaining wall as an acceptable alternative where savings to cost and program are anticipated. The Team works closely with the Bridge Team on any structural design changes needed during construction because of changed site conditions. the allowable bearing pressure of the soil and the minimum required depths of the foundation units. The Bridge Design Team also selects walls which will handle differential settlement. and provides details for drainage on drawings. The Geotechnical Team will also recommend soil strength parameters and groundwater elevations for computing design lateral earth pressure. The special provisions will specify the pre-approved wall systems which are acceptable for the particular application and site and the proprietary wall type is to be chosen from a pre-approved list of wall types. 801.02 Geotechnical Team The Geotechnical Team is responsible for investigating the site. differential settlement and the time rate of settlement for walls on compressible foundation soils.03 Bridge Design Team The Bridge Design Team is responsible for the design of the structural elements of the wall. assisting the construction supervision team as requested concerning geotechnical issues. They are also responsible for determining the maximum safe slopes allowed during excavation. drilling exploratory holes as required.03. the length of the wall and for producing the required construction drawings. The contractor or the specialized sub-contractor who is employed directly by the contractor will be responsible for the design of the system. when requested by others.03. The Geotechnical Team prepares appropriate Special Provisions for construction of the retaining walls and monitors construction of the foundation elements. when present. including the checking and certifying of the design in accordance with the category of structure as defined in Part 3 – Section 100. Clause 101. Blockouts for lighting. Minimum design life. 5. 9. signing. 6. Maximum coefficient of friction against sliding. 3. Water table level. 7. Allowable bearing pressure. Elevation of footing bottom. 2. The minimum factor of safety against overturning. 4. As a minimum the following should be included: 1. Maximum tolerable deflection.0 Part 3 – Section 800 Page 4 of 4 November 2014 . Version 2. Phi angle and other backfill properties. handrail or other attachments. The Geotechnical Team will prepare special provisions containing the design criteria to be used in evaluating the proprietary wall. The minimum factor of safety against sliding. 8.ROADWAY DESIGN MANUAL The Roadway Design Team will prepare drawings showing the location and extent of the walls and the profile along the top of the wall and the soil profile along the front face of the wall. The drawings should also show any restrictions regarding excavation which may exist and requirements for appurtenant features such as traffic barrier. utilities and drainage structures will also be detailed on the drawings or identified to be included with the proprietary plan submittals. 0 Part 0 – Divider November 2014 .ROADWAY DESIGN MANUAL SECTION 900 : PEDESTRIAN BRIDGES Version 2. 6th Edition 2013. but the Consultant should check and verify the future requirements with the ADM Investment Section.ROADWAY DESIGN MANUAL SECTION 900 – PEDESTRIAN BRIDGES 901 DESIGN CRITERIA The general guidelines given in Part 3 – Structures of this document should be followed. In these cases. Pedestrian bridges should be designed. The design should allow for the future provision of mounting signs.0 KN/m2 should be considered. advertisement boards and banners on the structure. 902 LOAD TYPES 902. Version 2. Initially.0 Part 3 – Section 900 Page 1 of 4 November 2014 . Sixth Edition.03 WIND LOAD A basic wind speed of 160 kph with a gust factor of 1. fabricated and erected in accordance with the requirements of AASHTO LRFD “Guide Specifications for the Design of Pedestrian Bridges” (GSDPB). unless clarified or specified below.01 GENERAL Loads shall be considered as per the GSDPB. calculated as per the GSDPB. Wind pressure should be calculated assuming that a significant percentage of the exposed area of the bridge deck or frame is covered. unless specified otherwise.  AASHTO “LRFD Bridge Design Specifications”.  Other technical codes may be used in the design. Other relevant standards are as follows:  AASHTO “Standard Specifications for Structural Supports for Highways Signs. 2012 (includes 2013 interim revisions). except where stated otherwise in this Section 900 – Pedestrian Bridges.04 OTHER LOADS Vehicular loading should only be applied if maintenance vehicles can reach the superstructure. Luminaires and Traffic Signals”.02 PEDESTRIAN LIVE LOAD A uniform pedestrian live load of 5. reference AASHTO LRFD US-6-M. subject to prior approval from ADM. refer to the GSDPB for the vehicle configuration to be assumed. 902. 902. 902. 80% of the exposed area should be assumed to be covered by signage.14 is to be assumed for wind loading. Other loads shall be considered as per AASHTO LRFD. construction costs. etc. A minimum clear width of 2. 903. but also aesthetics.Section 100. Modular/prefabricated construction is the preferred option for the superstructure. substructure and approach structures (retaining walls. steel frames. 903.12 should be applied. 903. Examples of superstructure types are concrete slab. non-truss approach spans.ROADWAY DESIGN MANUAL Vibration control provisions should be considered. approach slabs. The AASHTO LRFD earthquake provisions for pedestrian bridges. steel girder and prefabricated truss. However. assuming in-situ or precast concrete. structural configuration and approach transitions should be selected taking into consideration not only geometrical aspects of the particular site. as specified in the GSDPB. Version 2.4m should be assumed.03 DESIGN LIFE All pedestrian bridges should be designed for a 75 year design life.02 METHOD OF CONSTRUCTION Foundations. pre-stressed concrete girder. constructability. This analysis should include an assessment of the future demands. the Contractor shall appoint a consultant to design the pedestrian bridge. Vibration frequency should also be checked for critical cases during the construction period. Clause 201. etc. ramps and stairs) are to be fully detailed by the Consultant on the Drawings.01 TYPE OF STRUCTURE The type of structure. which will also be designed by the Consultant.0 Part 3 – Section 900 Page 2 of 4 November 2014 .04 WIDTH The horizontal clear width of the bridge should allow the smooth flow of pedestrian traffic during peak hours. as modified in Part 3 – Section 200. 903 DESIGN CRITERIA 903. which is then subject to verification based on the appropriate category of structure as described in Part 3 . in the case of design and build contracts. based on existing movements and proposed developments that are predicted to attract pedestrian traffic in the vicinity of the structure. unless otherwise specified. pipes or other approved systems to convey water to ground level. Design and Operation of Pedestrian Facilities”. 903. should have a height of 1. 903. Clause 102. 903. or in locations with site-specific safety concerns.0 Part 3 – Section 900 Page 3 of 4 November 2014 . followed by a suitable paint system consisting of the following two-component items:  Polyamide adduct-cured epoxy primer (suitable for galvanized steel surfaces). Discharge directly on to roadways beneath the bridge is not permitted. Version 2. The first stage is hot-dip galvanization (minimum thickness 86 microns).06 DEFLECTION Flexural members are to be designed to have adequate stiffness to limit deflection or any deformations which may adversely affect the strength or serviceability of the structure at service load plus impact. Bicycle railing on a bridge or bridge approach.10 LIFTS AND STAIRS Access facilities such as lifts and stairs should be designed in accordance with the AASHTO “Guide for the Planning.07 TRAFFIC BARRIERS AND RAILINGS Concrete barriers should be used for protecting the bridge abutment/piers and columns. Such barriers should comply with the requirements of AASHTO LRFD and relevant ADM road safety requirements. if not designed for the vehicular collision condition.ROADWAY DESIGN MANUAL 903. 903.08 LIGHTING Refer to Part 3 – Section 100.09 DRAINAGE Drainage of the structure should be provided as required by the use of kerbs. Design Criteria.11 regarding lighting requirements. minimum thickness 50 microns. 903. navigation clearances shall comply with the requirements of the concerned authorities.11 PROTECTIVE COATING Steel structural elements should be treated with a dual corrosion protection system.05 VERTICAL CLEARANCE Clearances above the bridge deck should be based on the requirements of GSDPB. The maximum allowable deflection should be limited to [span/500] for pedestrian and any maintenance vehicle loading. For bridges over waterways.4m. 903. ROADWAY DESIGN MANUAL  Solvent-free, high build, polyamine cured epoxy, minimum thickness 400 microns (applied in two coats).  Acrylic polyurethane, minimum thickness 100 microns (applied in two coats). All components will require the approval of ADM. Welding should be avoided after galvanization where possible, but if this cannot be avoided (for example where the fabricated units are too large to fit in the galvanization baths), any required repairs shall be carried out in accordance with ASTM A780. 903.12 INSPECTION AND MAINTENANCE Access shall be provided to critical parts of the structure for the purposes of inspection and maintenance, including rehabilitation and replacement works when required. This will include, but not be limited to, bearings, expansion joints and jacking points. Version 2.0 Part 3 – Section 900 Page 4 of 4 November 2014 ROADWAY DESIGN MANUAL SECTION 1000 : MISCELLANEOUS Version 2.0 Part 0 – Divider November 2014 ROADWAY DESIGN MANUAL SECTION 1000 – MISCELLANEOUS 1001 TRAFFIC SIGN STRUCTURAL SUPPORTS All structural supports for Highway Signs, Luminaires and Traffic Signals shall be designed, fabricated, and erected in accordance with AASHTO “Standard Specifications for Structural Supports for Highways Signs, Luminaires and Traffic Signals”, 6th Edition 2013. The basic wind speed considered in design shall be 160 kph, with a gust factor of 1.14. When possible, the designer should avoid overhead sign structures on the bridge deck. In cases where sign structures are mounted on a bridge, the concrete around the anchor bolt group and connecting elements to the bridge structure shall be designed to AASHTO LRFD. 1002 UTILITIES IN STRUCTURES 1002.01 GENERAL Existing utilities such as water, power, telephone, cable TV and gas lines which conflict with the proposed construction works will be relocated as required. Where it is feasible and reasonable to locate utility lines elsewhere, attachment to structures will not be permitted. Trenching in the vicinity of existing piers or abutments shall be kept a sufficient distance from foundations, as agreed with ADM, to prevent undercutting of existing footings or disturbing soils for future foundations. Where other locations prove to be extremely difficult and very costly, utility lines may be allowed in structures, provided that this does not cause any adverse effect on the structure. The Consultant should coordinate with the relevant utility authorities and obtain approval for the proposed designs and future maintenance arrangements. The Consultant should take into consideration the effect of differential vertical/horizontal movement of the bridge deck on utilities installed through the structure. Provision for the accommodation of relocated and future utilities on structures should follow the following General Policy: 1002.02 GENERAL POLICY Service provisions shall be as required by the concerned authorities. Protection culverts for oil, water, sewer and electricity shall be designed according to both the requirements of ADM and those of the concerned authority. For services carried by the bridge, proper inspection and maintenance access shall be provided and agreed with the service provider. Support bracket details and attachments for all utilities should be carefully considered and designed by the Consultant. All approved utilities shall have individual sleeved casings, conduits or ducts as appropriate. All Version 2.0 Part 3 – Section 1000 Page 1 of 7 November 2014 ROADWAY DESIGN MANUAL utilities carrying liquids shall be placed inside casings through the entire length of the structure. The casings shall be designed to carry full service pressure, so as to provide a satisfactory containment in case the utility is damaged or leaks. Water lines, telephone conduits, power lines, cable TV lines, supports or other related items will not be permitted to be suspended below or attached to the exterior of any new or existing structure. The possibility of providing natural gas lines over structures will need to take into consideration all requirements and necessary precautions required by the concerned utility authority. However, even if this is approved by the service provider, the Consultant shall conduct risk analysis and consider any mitigation measures for such a provision and obtain ADM approval to proceed on this basis. Product lines for transmitting volatile fluids will not be permitted to be attached to or suspended from or placed within any new or existing structure. 1002.03 BRIDGE DESIGN TEAM RESPONSIBILITIES The Consultant’s Bridge Design Team shall be responsible for determining the following during the design: 1. The number and type of utilities, if any, the structure can accommodate. 2. Where these utilities should be located within the structure. 3. Size of access openings and design of the required reinforcement. 4. Potential problems related to project programming. Usually utilities will be accommodated by providing individual access openings for casings and sleeves to pass through. Access openings should be 50mm larger than the diameter of the casings or sleeves and spaced as required by structural considerations. For box girder bridges, access openings should be located as low as possible, but no lower than 250mm above the top of the bottom slab to allow for support brackets to be supported from the bottom slab. Where possible, all utilities should be supported from the bottom slab of box girder bridges and should not be placed in the exterior girder bay. 1003 FALSEWORK POLICY FOR BRIDGE CONSTRUCTION 1003.01 FALSEWORK REQUIREMENTS To ensure that traffic management is given proper consideration in the early design stages, it is necessary to identify traffic handling and falsework assumptions in the Bridges and Highway Version 2.0 Part 3 – Section 1000 Page 2 of 7 November 2014 ROADWAY DESIGN MANUAL Structures Concept Report. If falsework is to be used, the horizontal and vertical clearances shall be shown on the General Plan. Usually, one of the following listed conditions will prevail: 1. Traffic will be routed around the construction site. 2. Traffic will pass through the construction site. a. No falsework allowed over traffic. This restriction would require precast concrete or steel superstructure with field splices located clear of traffic. b. Staged construction required. Staged construction must be detailed on the plans. Construction joints or hinges would be required. c. Falsework openings required. The size and number of openings must be shown. A general discussion and a table of falsework openings are covered in Section 1003.03, Falsework Clearances. 1003.02 FALSEWORK USE When traffic must pass through the construction site, three possible conditions exist as mentioned above. Condition 2 (a) is limited to sites which can be spanned by precast members or where steel is competitive in cost and the staged construction option of Condition 2 (b) may alternatively be considered where feasible. Condition 2 (c) is used for all other cases when it is necessary to route traffic through the construction site. The elimination of permanent obstructions by using longer spans and eliminating shoulder piers will usually outweigh objections to the temporary inconvenience of falsework during construction. 1003.03 FALSEWORK CLEARANCES For cast-in-place structures, the preferred method of construction is to route traffic around the construction site and to use earth fills for falsework. This provides an economical solution, a safe working area and eliminates possible problems associated with the design, approval, construction and performance of falsework including the possible effect of excessive deflections of falsework on the structure. When the street or highway must be kept open and detours are not feasible, falsework shall be used with openings through which traffic may pass. As the width of traffic openings through falsework can significantly affect costs, special care should be given to minimizing opening widths consistent with traffic and safety considerations. The following should be considered: 1. Staging and traffic handling requirements. 2. The width of approach roadway that will exist at the time the bridge is constructed. 3. Traffic volumes and percentage of trucks. Version 2.0 Part 3 – Section 1000 Page 3 of 7 November 2014 ROADWAY DESIGN MANUAL 4. Vehicular design speed. 5. Requirements of local agencies. 6. Controls in the form of existing facilities. 7. The practical problems of falsework construction. 8. Consideration of pedestrian requirements. The minimum width of traffic openings through falsework for various lane and shoulder requirements shall be calculated based on the number and width of the detour lanes with any shoulders, in addition to the roadside barrier width and associated safety margin/deflection zone. The actual width of traffic openings through falsework and the resulting falsework span to be used in design shall be agreed with ADM and the Consultant should include this information in the Bridges and Highways Structure Concept Report. To establish the grade line of a structure spanning an existing street or highway, allowance must be made for depth of falsework, where used, to provide the clearance needed to permit traffic through the work area during construction. However, the depth of falsework shall be designed checked based on the actual superstructure dimensions and falsework openings, in accordance with ADM requirements and international practice. In situations where falsework is designed by the Contractor, this will also require an independent third party review. The minimum vertical clearance for falsework over primary roadways shall be 4.5m, and shall be checked with the concerned authorities. Where the vertical falsework clearance is less than 4.5m, advance warning devices shall be specified or shown on the drawings. Such devices may consist of flashing lights, overhead signs, over-height detectors or a combination of these or other devices. Note to bridge designer: Special consideration shall be given to limit the maximum allowable tension in a pre-compressed tensile zone of post-tensioned box girder bridges supported on falsework with large openings. 1004 CONSTRUCTION JOINT GUIDELINES FOR BRIDGE CONSTRUCTION 1004.01 GENERAL The type of structure and method of construction, combined with sound engineering judgment, should be used in determining the number and location of construction joints. The use of construction joints should be minimized for ease of construction and subsequent cost savings. Some items which should be considered are: 1. Method of construction - earthen fill falsework, conventional falsework or girder bridge without falsework. Version 2.0 Part 3 – Section 1000 Page 4 of 7 November 2014 ROADWAY DESIGN MANUAL 2. Phased construction because of physical constraints such as traffic handling. 3. Span length and estimated rotation and deflection. 4. Degree of fixity at abutments and piers. 5. Effects of locating a construction joint in a region of negative moment. 6. Volume of concrete to be poured without a joint. 7. Consequences of continuous pour, including adverse effects caused by a breakdown during the pour. Construction joints will generally be limited to the positions indicated on the Drawings and to the types specified. These shall be perpendicular to the principal lines of stress and in general located at points of minimum shear and moment. Construction joints in abutment walls, wingwalls and barrels of box culverts should generally be placed at intervals not exceeding 9m, with shear keys or steel dowels used as appropriate. Waterstops should be installed in all joints where the ingress or egress of water is detrimental to the structure. All construction joints should normally be designed as bonded, unless specified as unbonded by the Consultant. Definitions of these types of joint are found in the AASHTO LRFD. The Consultant should indicate the sequence of pouring concrete to major structural elements on the Drawings, where the order of placement is found to be critical. However, the Contractor shall also submit shop drawings confirming the sequence and direction of concrete placement, and all other pertinent information to the Engineer in advance of carrying out the works for review and approval. 1004.02 LONGITUDINAL CONSTRUCTION JOINTS Longitudinal construction joints in bridge decks and/or superstructures should be avoided where possible. In situations where longitudinal joints cannot be avoided, for example for widening schemes or phased construction, they should preferably be located outside the girder flange and in a shoulder or median area. Joints should not be positioned under a theoretical wheel line. All longitudinal construction joints should be keyed. 1004.03 PRECAST CONCRETE GIRDER BRIDGES Precast concrete girder bridges made continuous over supports shall have transverse construction joints placed so that the girders undergo their positive moment deflections prior to the final pour over the negative moment areas of the fixed piers or abutments. There shall be no horizontal construction joint between fixed pier diaphragm or abutment diaphragm and the deck. Girder bridges will usually require details on the drawings showing a plan view with joint locations, deck pour sequence and direction of pour, if required. There should be a minimum of 12 hours Version 2.0 Part 3 – Section 1000 Page 5 of 7 November 2014 ROADWAY DESIGN MANUAL between adjacent pours. should be parallel to the centreline of the pier (the line of the bearings). Version 2.05 CAST-IN-PLACE BOX GIRDER BRIDGES Box girder bridges made continuous over supports shall have transverse construction joints placed so that the webs undergo their positive moment falsework deflections prior to the final pour over the negative moment areas of the fixed piers or abutments. 1004. should be generally be parallel to the centreline of the pier (the line of the bearings). where required.01 CONSULTANT The Consultant is responsible for the design of the structures included on the Drawings and as detailed in the Specifications. deck pour sequence and direction of pour. where large structural components are proposed or where unusual site access conditions are encountered.04 STEEL GIRDER BRIDGES The effects of uplift and allowing a continuous pour should be considered when developing deck pour schedules for multi-span continuous steel girder bridges. where required. if the adjacent spans are approximately equal length. 1005 RESPONSIBILITIES 1005. if required. The webs and all diaphragms should be poured concurrently with the bottom slab. if the adjacent spans are of approximately equal length. Construction joints. 1004. The transverse construction joints may be omitted if the superstructure formwork is supported on earthen fill. Transverse construction joints. Consideration must be given to the potential for negative moment stresses in the deck due to placement of positive moment pours in adjacent spans. where required. This distance is generally one-quarter of the span length from the pier. Their location should be near the point of dead load counter-flexure. The required rate of pour should be compared to the quantity of concrete to be placed and the potential for poured sections to set up and develop tensile stresses from pours in adjacent spans shall be considered when determining the need for construction joints. Their location near the inflection point is generally one-quarter of the span length from the pier. should be parallel to the centreline of the pier (the line of the bearings). Except where otherwise required. The Consultant shall also conduct preliminary investigations relating to shipping and handling. Construction joints. Their location will be near the point of minimum dead load plus live load moment and shear. A continuous pour from abutment to abutment will not be allowed.0 Part 3 – Section 1000 Page 6 of 7 November 2014 . Girder bridges will usually require details on the drawings showing a plan view with joint locations. there should be a minimum of 12 hours between adjacent pours. if the superstructure formwork is supported on conventional falsework. 0 Part 3 – Section 1000 Page 7 of 7 November 2014 . The Contractor is also responsible for investigating the stresses in structural components during handling.ROADWAY DESIGN MANUAL 1005. If the Contractor proposes changes to the design. the Contractor must redesign the structural components satisfying all ADM project requirements and verify that the alternative design is satisfactory by arranging an independent design check by a professional qualified engineering consultant. Shop drawings and all necessary supporting calculations shall be provided prior to construction and as-built drawings shall be produced after construction. transportation and erection.02 CONTRACTOR The Contractor is responsible for implementing the designs shown on the Drawings and as detailed in the Specifications. subject to ADM approval. Version 2. 0 Part 0 – Divider November 2014 .ROADWAY DESIGN MANUAL SECTION 1100 : REFERENCES Version 2. 3) AASHTO LRFD Guide Specifications for the Design of Pedestrian Bridges. Early Thermal Cracking of Concrete. reference AASHTO LRFD US-6-M.BD 36/92 and BA 28/92: Evaluation of Maintenance Costs in Comparing Alternative Designs for Highway Structures. 12) ADM Traffic Control Devices Manual 13) ADM Guidelines for Geotechnical Investigation 14) ADM Lighting Specifications for Roadway/Parking. Luminaires and Traffic Signals. 11) ADM Standard Specifications. Design and Operation of Pedestrian Facilities. 10) ADM Standard Drawings. 17) ADM Quality Control & Quality Assurance Procedures. Design Manual for Roads and Bridges.ROADWAY DESIGN MANUAL SECTION 1100 . Tunnels/Underpasses. 18) ADM Roadway Design Manual – Drainage. 6) Highways Agency (UK). 4) AASHTO Guide for the Planning. 16) ADM Road Safety Guidelines. 15) ADM Sustainability Guidelines. 7) Highways Agency (UK). 2) AASHTO LRFD Bridge Construction Specifications. 5) AASHTO Standard Specifications for Structural Supports for Highway Signs. 6th Edition. 2013. BD 28/87 and BA 24/87.REFERENCES REFERENCES FOR PART 3 – STRUCTURE DESIGN 1101 The following is a list of reference documents applicable to Part 3 – Structure Design: 1) AASHTO LRFD Bridge Design Specifications. 2012 (includes 2013 interim revisions). 8) BS EN 1993-5. Eurocode 3 – Design of Steel Structures – Part 5 : Piling 9) ADM Consultant Procedure Manual.0 Part 3 – Section 1100 Page 1 of 1 November 2014 . Part 1 . Version 2. 2010. 19) UPC Urban Street Design Manual (USDM). Lighting Poles and Public Lighting. Sixth Edition.