AS 4997—2005AS 4997—2005 Australian Standard™ Accessed by CONNELL WAGNER on 05 Feb 2008 Guidelines for the design of maritime structures This Australian Standard was prepared by Committee CE-030, Maritime Structures. It was approved on behalf of the Council of Standards Australia on 29 March 2005. This Standard was published on 28 September 2005. The following are represented on Committee CE-030: Association of Australian Ports and Marine Authorities Association of Consulting Engineers Australia Australian Stainless Steel Development Association Boating Industry Association of Australia Cement Concrete & Aggregates Australia – Cement Civil Contractors Federation Engineers Australia Institute of Public Works Engineering Australia Marina Association of Australia Monash University Queensland Transport University of Wollongong Accessed by CONNELL WAGNER on 05 Feb 2008 Keeping Standards up-to-date Standards are living documents which reflect progress in science, technology and systems. To maintain their currency, all Standards are periodically reviewed, and new editions are published. Between editions, amendments may be issued. Standards may also be withdrawn. It is important that readers assure themselves they are using a current Standard, which should include any amendments which may have been published since the Standard was purchased. Detailed information about Standards can be found by visiting the Standards Web Shop at www.standards.com.au and looking up the relevant Standard in the on-line catalogue. Alternatively, the printed Catalogue provides information current at 1 January each year, and the monthly magazine, The Global Standard, has a full listing of revisions and amendments published each month. Australian StandardsTM and other products and services developed by Standards Australia are published and distributed under contract by SAI Global, which operates the Standards Web Shop. We also welcome suggestions for improvement in our Standards, and especially encourage readers to notify us immediately of any apparent inaccuracies or ambiguities. Contact us via email at
[email protected], or write to the Chief Executive, Standards Australia, GPO Box 476, Sydney, NSW 2001. This Standard was issued in draft form for comment as DR 02536. AS 4997—2005 Australian Standard™ Guidelines for the design of maritime structures Accessed by CONNELL WAGNER on 05 Feb 2008 First published as AS 4997—2005. COPYRIGHT © Standards Australia All rights are reserved. No part of this work may be reproduced or copied in any form or by any means, electronic or mechanical, including photocopying, without the written permission of the publisher. Published by Standards Australia, GPO Box 476, Sydney, NSW 2001, Australia ISBN 0 7337 6858 X AS 4997—2005 2 PREFACE This Standard was prepared by Standards Australia Committee CE-030, Maritime Structures. The objective of this Standard it to provide designers and regulatory authorities of structures located in the marine environment with a set of guidelines and recommendations for the design, preservation and practical applications of such structures. These structures can include fixed moorings for the berthing of vessels, piles and other parts of a substructure, wharf and jetty decks, building substructures over waters, etc. Accessed by CONNELL WAGNER on 05 Feb 2008 This Standard has been prepared as a guideline only, to provide advice and recommendations for maritime structures. Clauses in this document are written using informative terminology and should not be interpreted otherwise. The requirements of a maritime structure and its associated facilities should be determined for the individual application. This Standard should be used in conjunction with the relevant materials and design Standards. 3 AS 4997—2005 CONTENTS Page SECTION 1 SCOPE AND GENERAL 1.1 SCOPE ........................................................................................................................ 5 1.2 REFERENCED AND RELATED DOCUMENTS ...................................................... 6 1.3 NOTATION ................................................................................................................ 7 1.4 DEFINITIONS ............................................................................................................ 8 SECTION 2 SITE INVESTIGATION AND PLANNING 2.1 GENERAL ................................................................................................................ 10 2.2 SURVEY ................................................................................................................... 10 2.3 GEOTECHNICAL..................................................................................................... 11 2.4 ASSESSMENT OF LOADS...................................................................................... 11 SECTION 3 DIMENSIONAL CRITERIA 3.1 STRUCTURE HEIGHTS .......................................................................................... 12 3.2 FENDER HEIGHTS.................................................................................................. 12 3.3 LAYOUT OF BERTH STRUCTURES ..................................................................... 12 3.4 ACCESS AND SAFETY........................................................................................... 13 Accessed by CONNELL WAGNER on 05 Feb 2008 SECTION 4 DESIGN REQUIREMENTS 4.1 AIM ........................................................................................................................... 14 4.2 DESIGN REQUIREMENTS ..................................................................................... 14 4.3 FLOATING STRUCTURES ..................................................................................... 15 4.4 BREAKWATERS ..................................................................................................... 15 4.5 EFFECTS OF SCOUR AND SILTATION................................................................ 16 4.6 SEA LEVEL RISE (global warming) ........................................................................ 16 SECTION 5 DESIGN ACTIONS 5.1 GENERAL ................................................................................................................ 17 5.2 PERMANENT ACTIONS (DEAD LOADS)............................................................. 17 5.3 IMPOSED ACTIONS (LIVE LOADS) ..................................................................... 17 5.4 WIND ACTIONS ...................................................................................................... 21 5.5 CURRENT ACTIONS............................................................................................... 22 5.6 DEBRIS ACTIONS ................................................................................................... 23 5.7 NEGATIVE LIFT DUE TO CURRENTS ................................................................. 23 5.8 HYDROSTATIC ACTIONS ..................................................................................... 23 5.9 WAVE ACTIONS ..................................................................................................... 24 5.10 CONSTRUCTION AND MAINTENANCE ACTIONS ............................................ 26 5.11 LATERAL EARTH ACTIONS ................................................................................. 26 5.12 COMBINATIONS OF ACTIONS ............................................................................. 26 5.13 PROPELLER WASH ................................................................................................ 28 5.14 EARTHQUAKE ACTIONS ...................................................................................... 28 SECTION 6 DURABILITY 6.1 GENERAL ................................................................................................................ 30 6.2 DESIGN LIFE ........................................................................................................... 30 6.3 CONCRETE .............................................................................................................. 33 6.4 STEEL....................................................................................................................... 38 6.5 TIMBER.................................................................................................................... 41 ...................................... 43 B BERTHING ENERGIES AND LOADS ..................................................................................................................................................................................AS 4997—2005 4 Accessed by CONNELL WAGNER on 05 Feb 2008 APPENDICES A CONTAINER WHARF DECK LOADINGS. 50 ...... 46 C MOORING LOADS ..... . This Standard is intended to cover the design of near-shore coastal and estuarine structures. e. (b) wharves.com. (G) floating structures not permanently restrained. The superstructure above main deck level should be designed in accordance with the relevant Australian Standards and relevant building regulations.5 AS 4997—2005 STANDARDS AUSTRALIA Australian Standard Guidelines for the design of maritime structures SECT ION 1 SCOPE AND GENERA L 1. (C) offshore oil and gas structures. (D) dredging and reclamation.standards.au Standards Australia .1 SCOPE This Standard sets out guidelines for the design of structures in a marine environment. (h) laterally restrained floating structures. (e) seawalls. (E) coastal engineering structures such as rock armoured walls. such as— (a) jetties. construction pontoons. (d) floating berths. (f) breakwater structures. groynes. (B) marinas (see AS 3962). vessels. www. and (i) building substructures over water. (F) geometrical design of port and harbour infrastructure.g. barges. excluding rubble mound and floating types. (c) berthing dolphins. etc. (g) boat ramps. Accessed by CONNELL WAGNER on 05 Feb 2008 This Standard is not intended to cover the design of— (A) pipelines. It is to be used in conjunction with the relevant Standards and provides recommendations additional to the requirements of these Standards. these guidelines apply to the structure up to and including the main deck level. For buildings constructed over water. standards.au .1 1170.2.2.1 Referenced documents The following documents are referenced in this Standard: AS 1012 1012.13 Methods of testing concrete Method 13: Determination of the drying shrinkage of concrete for samples prepared in the field or in the laboratory. imposed and other actions Part 2: Wind actions 1554 1554.2 REFERENCED AND RELATED DOCUMENTS 1. construction and installation 3600 Concrete structures 3962 Guidelines for design of marinas 3972 Portland and blended cement 4100 Steel structures 5100 5100.4 Minimum design loads on structures Part 4: Earthquake design loads on structures 1604 Timber—Preservative-treated—Sawn and round 1657 Fixed platforms.2 Related documents AS/NZS 1664 Aluminium structures AS 5100 Bridge design (all parts) SA HB 84 Guide to Concrete Repair and Protection Standards Australia www.com.AS 4997—2005 6 1.6 Structural steel welding Part 6: Welding stainless steels for structural purposes 2312 Guide to the protection of iron and steel against exterior atmospheric corrosion 2832 Cathodic protection of metals (all parts) 4671 Steel reinforcing materials 4673 Cold formed stainless steel structures 4680 Hot-dip galvanized (zinc) coatings on fabricated ferrous articles BS 6349 Maritime structures (all parts) 6744 Stainless steel bars for the reinforcement and use in concrete – Requirements and test methods Disability Standards for Accessible Transport (Australian Government) PIANC Design of fender systems—2002 1. walkways. stairways and ladders—Design.2 Structural design actions General principles Part 1: Permanent. 1170 1170.0 1170.2 Bridge design Part 2: Design loads 5604 Timber—Natural durability ratings Accessed by CONNELL WAGNER on 05 Feb 2008 AS/NZS 1170 1170. standards.2)) LOA = Length Overall of a vessel.9.2 Symbols Accessed by CONNELL WAGNER on 05 Feb 2008 The following symbols are used in this Standard.com. crew and reserves with which a vessel is laden when submerged to the summer loading line. usually about the same level as AHD 1. HAT = Highest Astronomical Tide (see Clause 3. in kilonewtons (kN) Fe = earth pressure loads F env = combined environmental loads www.dsb = design action effects destabilizing structure E d. used for the preparation of navigation charts.1 Abbreviations The following abbreviations are used in this Standard.3.7 AS 4997—2005 1.u = berthing impact actions under abnormal conditions FD = action in the direction of wind.83 m 3 (100 ft 3)). AHD = Australian Height Datum CD = Chart Datum. stores. ship-to-shore crane) DWT = Dead Weight Tonnage (The total mass of cargo. MSL = Mean Sea Level.1) f′ c = characteristic compressive strength of concrete. fuels.stb = design action effects stabilizing structure Es = serviceability earthquake action Eu = ultimate earthquake action f = co-efficient of wave height (see Clause 5.2) ISLW = Indian Spring Low Water (Obsolete estimate of Lowest Astronomical Tide (LAT) formerly used as chart datum) LAT = Lowest Astronomical Tide (Now adopted as chart datum for all Australian Hydrographic Charts (see Clause 3.3 NOTATION 1. in Megapascals (MPa) fs = steel reinforcing stress. GRT = Gross Registered Tonnage (The gross internal volumetric capacity of the vessel as defined by the rules of the registering authority and measured in units of 2.) NOTE: Although this represents the load carrying capacity of the vessel it is not the exact measure of cargo load. measured to the extremities of fittings.3. in Megapascals Fb = berthing impact loads F b. and usually about the same level as LAT CQC = Container Quay Crane (Portainer crane.au Standards Australia . db = reinforcing bar diameter Ed = design action effect E d. standards. in metres per second 1. including debris loads F wave.4. 1. Standards Australia www.4. 1.3.4 DEFINITIONS For the purpose of this Standard. in the analysis of structures.5) P = pressure.au . 1.S = wave loads under serviceability conditions (1 in 1 year) F wave.1) F lp = liquid pressure load Fm = mooring loads Fs = stream flow loads. 1.5 Significant wave height (Hs ) The average height of the highest one-third of waves in any given time interval.2 Design life The period for which a structure or a structural element remains fit for use for its intended purpose with appropriate maintenance (see Clause 6. Used.4.4 Load The value of a force appropriate to an action. It approximates the wave height for this train of waves as estimated by an expert observer.3 Design wave (H1) The highest 1% of waves in any given time interval. in metres per second v = current velocity. 1.4.com.AS 4997—2005 8 F gw = ground water loads F lat = minimum lateral load (see Clause 5. or deformation imposed on a structure or constrained within it (indirect action).U = wave load under ultimate strength conditions g = acceleration due to gravity G = permanent action (dead load) H1 = wave height used for design of structures (see Clause 1.2). the definitions below apply.3) Hs = significant wave height (see Clause 1.1 Action Set of concentrated or distributed forces acting on a structure (direct action). Accessed by CONNELL WAGNER on 05 Feb 2008 NOTE: The term load is often used to describe direct actions.4.4.4) Ts = period of significant waves Ws = wind load for serviceability limit state Wu = wind load for strength limit state V = design wind speed.12. for example. in kilopascals (kPa) Q = imposed action (live load) Su = loading combination (see Clause 5.4. www.8 Vessel displacement The total mass of a vessel and its contents. 1. no longer under the influence of generating wind.7 Swell waves Waves generated some distance from the site.com.4.10 Wind wave Accessed by CONNELL WAGNER on 05 Feb 2008 Waves formed under the influence of local generating winds. 1. to strengthen and protect vessel from berthing impacts.9 AS 4997—2005 1.4.4. NOTE: This is equal to the volume of water displaced by the vessel multiplied by the density of the water. generally at main deck level.9 Vessel wash Waves formed by the passage of a vessel.6 Sponson Rubbing strip. 1. 1.standards.4.4. usually called seas.au Standards Australia . currents and other pertinent analysis and design parameters. The survey data should also contain sufficient detail to enable an assessment of the hydraulic and seabed processes affecting the proposed structure and adjacent foreshores. berthing and other actions that may be applicable to the structure should be considered in the site investigation. Such surveys and subsequent investigations (e. 2. Standards Australia www.2 SURVEY 2. which may be Chart Datum (CD) or Australian Height Datum (AHD). Maritime structures that have the potential to obstruct currents and waves are likely to affect the littoral processes and the effect of such structures on the adjacent natural features must be investigated. geotechnical) should adopt a uniform survey grid. The wind. Where a local survey grid is adopted.2. Height datum levels for hydrographic surveys should be to the relevant Chart Datum. current.2.standards.1 GENERAL In maritime structures. as it provides direct correlation to navigable water depths.au . wave.g. 2. e.1 Survey grid A uniform survey grid should be adopted for the project area. a detailed site investigation should be undertaken to provide sufficient information for the design and construction of the structure. International Survey Grid or Map Grid of Australia 1994 (MGA94).. 2.. Detailed site investigations are an essential part of the planning and design of maritime facilities. for projects in Australia. this should be clearly noted on the drawings and the correlation to GRS80 or WGS84 grid should be nominated on the drawings.2. The correlation between CD and AHD for the specific location should be clearly shown on all the drawings.2.3 Hydrographic survey The hydrographic survey should be undertaken to cover the proposed site of works and any adjacent near-shore water up to mean high water level.g. Consideration should be given to incorporating the survey grid for the project area into the regional coordinated survey grid. All terrestrial and hydrographic surveys should use this survey grid. 2. for any site on which it is proposed to install a maritime structure. Hydrographic and terrestrial surveys should be undertaken.g. Chart Datum is the preferred datum for surveys and mapping of maritime works and offshore topography.2 Survey datum Accessed by CONNELL WAGNER on 05 Feb 2008 All survey data should be reduced to a recognized datum.com.AS 4997—2005 SECT ION 10 2 S ITE I N V E ST IG AT I ON P L ANN I NG AND 2. including adjacent navigable waterways where there is insufficient existing survey data to make an appropriate assessment of design waves. the effect of the local environment and geographical configurations (including the new configuration after completion of the proposed maritime facility) has significant bearing on the performance of the structures.4 Terrestrial surveys Terrestrial surveys should be provided over any land areas that will be incorporated or impacted upon by the project site and should overlap with the hydrographic survey. by a note or a diagram. Thus.. e. or affecting. the ultimate (survival) loads that the facility may be expected to withstand. for the site of the works should be determined and appropriate design maximum and minimum tidal planes established. 2. If such records are not available. wave heights and periods may be determined from available wind data.3 GEOTECHNICAL The geotechnical properties and design parameters of seabed materials in the vicinity of a maritime structure should be assessed. Wind. where records of adequate duration. wave. to determine an appropriate long-term record. Such processes include tides. flood debris) should be considered during any investigation of loads applied to. tide. current and storm surge and other such natural loads and conditions (including sediment movement. current and wave actions and effects of propeller and boat wash.6). are available.2 and/or site-specific anemometer records. and effect on the prevailing natural coastal and estuarine processes. www. are available.au Standards Australia . These parameters should be used to evaluate foundation capacity. the performance of a maritime structure. to determine an appropriate long-term record. Accessed by CONNELL WAGNER on 05 Feb 2008 Changes in water levels due to global warming should be considered (see Clause 4.standards. Wind data should be determined from AS/NZS 1170. The determination of wave parameters used to derive the design wave height. stability and settlement characteristics of the structures and associated works and to determine the response to. Tidal information.4 ASSESSMENT OF LOADS Maritime structures should be designed to resist the loads applicable to the service performance requirements of the completed facility.11 AS 4997—2005 2.com. including tidal currents. as well as loads applicable at the various stages of construction. wave period and wave direction should be assessed using site-specific wave records where records of adequate duration. at the lowest level that can be predicted to occur under average meteorological conditions and any combination of astronomical conditions (LAT). (c) allowing safe navigation access to the berth to and from the waterway. (f) safe personnel and vehicle access.2 FENDER HEIGHTS Fender structures in tidal waters should extend to at least the height of the sponson or rubbing strake of the highest vessel likely to use the facility. which should be no lower than the highest level that can be predicted to occur under average meteorological conditions and any combination of astronomical conditions (HAT) plus an allowance for storm surge. the design may allow for periodic inundation during such events. Such structures should be able to withstand lateral loads and uplift from elevated water levels including flood effects from the design flood event.au .standards. (b) providing safe berthing and deberthing in extreme events (storms. Vessel load conditions and motion in response to waves and any other influencing effects should also be considered. For wharves and jetties in locations subject to local river flooding or storm surge situations.AS 4997—2005 12 SEC T I ON 3 D IM E N S I O N A L CR IT E R I A 3. plus a suitable freeboard depending on exposure to waves. The minimum height of deck of a wharf or jetty in tidal conditions should be determined as the 1/100 annual exceedance of probability elevated water level. (d) minimum intrusion into the navigable waterway. formation of bars at river entrances and seiche. during the design elevated water level. (e) ease of cargo handling. wave heights.com. (g) disabled access (where applicable). wind set-up. in keeping with their function to provide access to the waterway and to floating vessels.1 STRUCTURE HEIGHTS Deck levels should generally be kept as low as practicable. The fender system should also extend down to a level no lower than the sponson of the smallest craft likely to use the facility. floods). and (h) minimum impact on the hydrodynamic regime. Standards Australia www. means to prevent water damage to the property should be incorporated in the design.3 LAYOUT OF BERTH STRUCTURES Accessed by CONNELL WAGNER on 05 Feb 2008 The layout of the structures for a berth should be designed to take account of— (a) restraining the vessel against environmental loads (winds. waves and currents) and interaction effects between passing vessels. 3. 3. Where overtopping of deck structures by waves would result in disproportionate level of damage to the superstructure above main deck level. NOTE: The operation of some facilities may require that some vessels be removed in the event of a major storm. structures should comply with the requirements of the Disability Standards for Accessible Public Transport. safety ladders should be provided. access should be provided by way of a series of horizontally surfaced steps let into the slope. the structures should comply with the requirements of AS 1657.4.4. Appropriate non-slip surfacing should be provided.1 Application For maritime structures that may fall outside the provisions of relevant building codes or other regulations.13 AS 4997—2005 3.4 Safety fencing In general. suitable buffer rails. or steeper than 1 in 12 for more than 20% of the time.2.5 m to strike a hard surface or the seabed.5 Safety ladders Accessed by CONNELL WAGNER on 05 Feb 2008 Where persons who fall from a wharf or maritime facility would not be able to easily regain the shore. at least 250 mm proud of the ladder. 3. Where access to the water or vessels is not required and where a person falling from the structure is likely to fall more than 1. 3. 3. the guidelines in Clause 3. 3. wharf faces and the like are not provided with safety or other fencing to prevent persons or vehicles from falling off the edge of a public access structure. Where safety ladders are used to provide access to craft. Ramps or sloping surfaces should not be located in the tidal zone (where marine growth can make them slippery). Such ladders should be of durable material and extend from deck level down to below low water level—bottom rung should be 300 mm below LAT. Gradients of gangways (hinged ramps attached to floating structures. Where slopes are required below high water mark.4 and 3.4.4. maintenance and servicing personnel Where access to structures is required for operational.4.standards.5 should be followed.com. Edge kerbs may be considered in areas generally used by wheeled vehicles. 3. inspection. a guardrail (handrail) in accordance with AS 1657 should be provided. proud of the slope. Such ladders should be located at maximum 60 m intervals.au Standards Australia .4.3. www. or cleats fixed to the surface at maximum 300 mm centres.4. whose gradients varies with the tide) should not exceed 1 in 8 when the tide is at LAT. 3. inspection and maintenance personnel.4.3 Access to public transport facilities Where access is required to public transport facilities.4 ACCESS AND SAFETY 3.2 Access for operational. Such fencing would hinder the normal operation of the wharf or maritime facility.4. should be provided each side to prevent vessels crushing persons on the ladder. com. 4.au .12.2. Under the load combinations for serviceability design detailed in Clause 5.4. braking) on the structure. Designers should exercise care at the interface between flexible maritime structures and rigid shoreline structures. 4. 4.4 Serviceability The structure and its component members should be designed for serviceability by controlling or limiting settlement. uplift and sliding and dynamic stability in design conditions as given in Clause 5.AS 4997—2005 14 S E C T I O N 4 D E S IG N RE Q U I RE M E N T S 4.1g.12 to determine the design loads for strength. where l is the distance between underside of the deck structure to the level of the support in the seabed. have adequate strength against ultimate conditions and remain serviceable while being used for their intended function..12. strength. economy and ease of construction. The design should be in accordance with the relevant Australian Standards together with any additional recommendations in these guidelines. (d) Determine the design strength in accordance with the requirements of the appropriate Australian Standard(s). 4.1 AIM The aim of the design of maritime structures covered by this Standard is to provide structures that are stable. and which also satisfy requirements for robustness.2 DESIGN REQUIREMENTS 4.12. current and other actions under both normal and storm conditions should be considered. such that stability loads and other actions exceed the destabilizing loads and other actions. stability. wave.2.2 Stability The structure and its component members should be designed for static stability under overturning. (b) Combine and factor the loads in accordance with Clause 5. Standards Australia www. The loads and other actions will need to be combined as given in Clause 5.standards. as appropriate. vertical deflection should be limited in accordance with the requirements of the appropriate materials Standards.g. Horizontal deflection and acceleration limits for trafficable structures should be limited to a maximum deflection of l/150.3 Strength The structure and its component members should be designed for strength as follows: (a) Determine the appropriate loads and other actions in accordance with Section 5. and a maximum acceleration of 0. (c) Determine the design action effects for the structure and its components for each load case.1 General The design of the structure and its components should take into account.2. serviceability and durability. and are durable (low maintenance and low repair costs).2. Horizontal deflection limits in commercial structures subject to heavy vehicle loadings need to consider dynamic effects of the horizontal vehicle loads (e. horizontal displacement and cracking. Accessed by CONNELL WAGNER on 05 Feb 2008 The effects of fatigue from wind. the load cases of full load intensity on the whole deck as well as the case of the full load intensity on part of the deck (e. The design of floating structures for full live load as well as full environmental loads (storm conditions) is not usually necessary. For large flotation structures (e. www.15 AS 4997—2005 For maritime structures. ferry landings) consideration should be given to allowing access from hatches in the deck. Accessed by CONNELL WAGNER on 05 Feb 2008 Floating structures should be designed to have watertight sealed compartments to prevent sinking or overturning in the event of a leak in the outer skin. 4. For horizontal cylindrical flotation systems.com.6 Other relevant design requirements The design should take into account the effects of vessel berthing. 4.. one side of the structure centre-line) should be investigated. under the most adverse design loading is 5% of the moulded depth (minimum 50 mm). Floating structures should be designed to maintain a safe freeboard under the most adverse combination of live load and environmental loads including consideration of dynamic effects.g. 4. restrained by piles or permanent moorings and generally in enclosed waters. When assessing stability of floating structures under live load. fatigue. once in one-year storm or wave) should be considered in analysis for stability and freeboard.standards.1). ignoring other operation constraints. scour. However live load under serviceability environmental conditions (e. Design considerations for breakwaters are that the structure should attenuate wave action without creating adverse conditions and be fit for purpose over their design life. which has dynamic effects as well as fatigue effects on those elements constructed from fatigue-prone materials.5 Durability The structure and its component members should be designed for durability in accordance with Section 6..g. NOTE: This Standard does not cover the design of rubble mound and floating breakwaters (see Clause 1. temperature effects and any other special performance requirements.au Standards Australia . freeboard should be at least 25% of the diameter of the cylindrical float. The minimum freeboard. cyclic loading.g.2. 4. Typically service conditions would include effects from waves with significant wave heights that occur once or more each year. measured from the top of the flotation unit for rectilinear flotation systems.4 BREAKWATERS The function of a breakwater is to reduce wave action either by attenuating the wave as it is transmitted or by reflecting part of the wave energy.. and may include for example wave action. measured from the top of the flotation system.2.3 FLOATING STRUCTURES Floating structures dealt with in this Standard include pontoons used for floating berths (ferry wharves and similar) that are stationary. serviceability conditions are those that may be experienced under normal conditions. flood. The structure should be capable of maintaining adequate freeboard (under dead load only) in the event of the external skin of any compartment being punctured and filling with water up to the external water level. 4. The allowance for sea level rise does not necessarily include the construction of the deck of the facility at a higher level.1.AS 4997—2005 16 4.6 SEA LEVEL RISE (global warming) Maritime facilities should be designed to cater for increase in water level due to promulgated sea level rises caused by global warming. and build-up of sediment in up-drift areas.5 EFFECTS OF SCOUR AND SILTATION Maritime structures and their component members should be designed to remain stable and of sufficient strength and not be overloaded in the event of temporary or permanent changes in the level of the seabed due to scour or silting. Wharves and jetties in river estuaries should be analysed with appropriate allowance for velocity-induced scour. Allowance for sea level rise may include options to raise the heights of restraining piles on floating structures at a later time. Wharves used by vessels should be designed to allow for this additional scour effect to the materials beneath the wharf from propeller wash or bow or stern thrusters.au . TABLE 4. Structures in coastal areas subject to littoral drift should be analysed with allowances for erosion of the seabed in down-drift areas.standards.com.1 50 years 0. or installing substructure of adequate strength to permit future topping slabs etc.2 100 years 0. which may be exacerbated at the peak of a flood event. The allowance for future sea level rise is provided in Table 4. These values are updated by IPCC from time to time. Standards Australia www. The amount of sea level rise to be considered depends on the design life of the structure. although in some cases this may be prudent.4 Accessed by CONNELL WAGNER on 05 Feb 2008 NOTE: Based on the mid-scenario from the International Panel on Climate Control (2001).1 ALLOWANCE FOR SEA LEVEL RISE Design life Sea level rise m 25 years 0. 1. www. etc. The loads indicated in Table 5.4). all deck wearing surfaces. (g) Thermal. or inside handrails. 5. as follows: (a) Permanent actions (dead loads) (see Clause 5. Concentrated loads should be applied at a critical location in one span in lieu of a distributed load. or as specified by the owner of the facility particularly for large port projects. superstructures. Piles and other elements immersed in the sea should include the influence of marine growth.3). Distributed loads should be applied over the whole of the deck between kerbs. and mooring fittings (bollards. 5. long-term loads such as cargo storage facilities. (d) Current and debris actions.2). serviceability. shrinkage and other movement induced actions. slewing/luffing loads from cranes. (h) Construction and maintenance actions.). or alternate spans to produce the worst design effect. (j) Propeller wash. For wharf decks that handle containers. (i) Lateral earth actions on waterfront structures (seawalls). (c) Wind actions (see Clause 5. Structures should be designed for directly related horizontal live load actions such as braking loads from vehicles.17 SE C T ION 5 DE S IG N AS 4997—2005 A C T IO NS 5.2 PERMANENT ACTIONS (DEAD LOADS) Dead loads include the self-weight of all structures.1 GENERAL The design for ultimate strength.1 Wharf deck loads Accessed by CONNELL WAGNER on 05 Feb 2008 Wharf surfaces should have a specified loading classification that will govern the design of all elements of the structure. quickrelease hooks. (b) Imposed actions (live loads) (see Clause 5.3. (f) Wave actions. (k) Earthquake actions. headstocks and piles. stability and other relevant limit states should take into account the appropriate design actions arising from those given in AS/NZS 1170.com. Loads should be applied to a single span.1 should apply as appropriate for the facility. in addition to the loads given in Table 5. or all spans. (e) Hydrostatic actions. etc. and other actions applicable to maritime structures. including deck. These loads need to be factored to obtain ultimate limit state (strength) design loadings.au Standards Australia . The design loads and classifications shown in Table 5.standards. the design of the wharf structure should be checked for the loads applicable for the particular arrangement of containers and container handling equipment as indicated in Appendix A.3 IMPOSED ACTIONS (LIVE LOADS) 5.1 and Appendix A are service loads. beams. 2 Vessel berthing and other imposed loads 5. T44 loading) Small mobile crane up to 20 t SWL Light-duty wharf and jetty for fishing industry.standards.0 NOTES: 1 The above loads do not include any component for dynamic effect (rolling ‘impact’. charter boat industry.3. mm) 20 kN (150 × 150) s = 1.au . ferry wharves. light commercial activities Bridge design code (SM1600 heavy platform loading) Mobile crane 50 t SWL Secondary port general cargo wharf Container forklift and other machinery for 40 ft containers Mobile crane 100 t SWL General cargo wharf or container wharf (For containers stacked 2 high ship-side. 3 The storage of containers on the wharf deck at ship-side is for temporary storage of containers while accessing containers within the vessel. see Note 3 & Appendix A) Mobile crane to 200 t SWL Heavy-duty maintenance wharf s = 1. international gateway container terminal (For containers stacked 2 high ship-side. Standards Australia www. applied at deck level. 2 s = spacing (metres) in any direction between concentrated loads. Passenger jetties Small emergency vehicles Public boardwalks and promenades with access for emergency vehicle and service vehicles Bridge design code (W7. Loadings in container yards are not covered by these guidelines.0 40 40 kPa 1000 kN (1000 × 1000) s = 7.8 15 15 kPa 200 kN (400 × 700) s = 4. This horizontal action should be applied in the lateral and longitudinal directions (not simultaneously) and should not be superimposed on any other applied horizontal actions.0 Accessed by CONNELL WAGNER on 05 Feb 2008 60 60 kPa Application s = spacing.1 MARITIME STRUCTURES —DECK LOAD CLASSIFICATIONS Class Uniformly distributed load (Q) (see Note 1) 5 5 kPa Concentrated load (area. Light motor vehicles up to 3 t tare Private and public boardwalks.AS 4997—2005 18 Any freestanding maritime structure (jetty.3.2. see Note 3 & Appendix A) Container forklift. Concentrated loads and uniformly distributed loads identified in the above table should not be superimposed. as such loads are terminal specific. reach stacker and other machinery for largest containers Mobile crane 150 t SWL Primary port. W8.5% of the maximum permanent and imposed vertical actions. etc. of at least 2.1 General The structure should be designed to withstand loads associated with the berthing of vessels within the design vessel range appropriate for its use. A160.) should be capable of withstanding a minimum horizontal load (F lat).8 10 10 kPa Anticipated load conditions 45 kN (300 × 150) Pedestrian crowd load.0 50 50 kPa 1500 kN (1000 × 1000) s = 8. 5. dolphin. or between concentrated loads and the edge of uniformly distributed loads.com. The impact and dynamic load factors should be applied as appropriate. TABLE 5.0 25 25 kPa 500 kN (700 × 700) s = 5. or heavy landings of cargo loads). m (see Note 2) 2000 kN (1000 × 1000) s = 9. mounted on the front of a rigid (or semi-rigid) wharf or dolphin structure.3. no deflection should be considered. to provide full restitution after loading.2.3.5 Determination of berthing energy and loads Where more accurate data is not available. (d) Through the action of a vessel forcing water between the vessel and the shore. should allow for absorption of the maximum (abnormal) berthing energy in elastic deflection of the structure and foundations. The loading in a flexible berthing structure may be reduced by providing an energy absorbing ‘soft’ fender system on the structure (see Clause 5.3 Energy absorbed through deflection of a berthing structure Some berthing structures may be designed to absorb berthing energy by deflection of the structure itself.2.3.au Standards Australia . (Accidental overload beyond abnormal berthing may result in permanent displacement of the structure). the berthing energy may be considered to be absorbed through deflection of the hull of a vessel as well as deflection of the berthing structure or berthing fender system. Design of flexible berthing structures. 5. (c) fender piles. berthing energy should be determined in accordance with Appendix B. in which case the berthing energy imparted to the structure will be reduced by the capacity of this fender system. (b) In deflection of the berthing structure. 5.3.com. (b) fender system restraint and reaction chains. hull deflections of up to 75 mm for quarter-point to mid-point berthing may be considered. in three axes of translation and in rotation.standards.) 5.4 Energy absorbing fender systems An energy absorbing fender system will usually comprise an elastomeric energy absorbing unit. and/or www. The berthing energy is dissipated and results in loads on the berthing structure that are either reaction loads induced during deflection of a flexible structure itself.2.19 AS 4997—2005 The energy of berthing vessels may be absorbed in one or a combination of the following ways: (a) In deflection of the vessel hull (usually only for small vessels <500 t). or reactions from the ‘soft’ fender system.2. For such vessels. such that the whole of the berthing energy is absorbed by the fender system.3.5). Accessed by CONNELL WAGNER on 05 Feb 2008 5.2. Reactions on a berthing fender system may be from any or all of— (a) elastomeric (‘soft’) fender unit. and associated contact faces. The structure should sustain the reaction loads from the fender system mountings. where it is specifically designed to flex under loading. (For end-impacts. to bring the vessel to a standstill. (c) Through an energy-absorbing berthing fender system mounted on a wharf or dolphin structure.2 Energy absorption through vessel hull In the case of small vessels up to 500 t displacement. The energy absorbed by the flexible structure is the integral of the reaction load from the structure over the displacement of the structure (at the point of contact with the vessel). such as flexible dolphins and berthing beams. jetty or dolphin structures by the mooring lines. For fender impacts exceeding the ultimate strength condition. they may be reduced with the use of low friction facing material on the fender frontal panel. malfunction or exceptionally adverse wind or current or a combination of these.3. particularly with passenger vessels.3 Mooring loads Mooring loads are loads generally applied to structures by mooring lines or ropes. The berthing energy calculated in accordance with Appendix B is the energy of the vessel approaching perpendicular to the wharf face. Shear loads are due to longitudinal and/or vertical friction on the face of the fender during vessel impacts. The ultimate strength design of the fender support structures should then consider the greater load of— (A) the rated fender reaction load. An abnormal berthing condition should also be considered in the fender design.standards. etc. care should be exercised to provide a soft fendering system for small craft. The fender system should be designed for the full range of design vessels for the facility. In abnormal berthing conditions. and thus represents the serviceability condition.au . considered as an ultimate Limit State load condition. the energy capacity of a fender system should be capable of absorbing 1. Loads applied to mooring bollards or similar fittings may be calculated using wind and current loads on the moored vessel. which should be applied to the fender support structure. Standards Australia www. This energy is based on normal operations. as well as friction loads that are longitudinal and vertical. For strategic installations. such as major single use facilities and oil or gas loading/unloading facilities. arising through mishandling. Mooring loads may also include loads resulting from vessels manoeuvring to or from the berth using engines and rudders while moored to bollards. with appropriate Limit State load factors applied. Where possible.. the designer should consider the ramifications of failure of the berthing structure.AS 4997—2005 (d) 20 loads may be normal to wharf (direct impact). transferred to the wharf. and (ii) abnormal berthing energy up to the maximum capacity of the fender unit.com. Accessed by CONNELL WAGNER on 05 Feb 2008 Shear and tension loads during fender impacts should be calculated for a range of possible berthing events. Where these loads are substantial. Such loads include wind and current loads on moored vessels. The corresponding fender unit reaction load should be applied as a lateral load into the berthing structure. These are transferred into the berthing structure through the body of the fender unit and/or restraint or reaction chains.25–2 times (or greater) the calculated normal berthing energy (refer to PIANC Guidelines). while still providing adequate capacity to absorb energy from the largest design vessel. 5. To cater for mooring loads from manoeuvring vessels bollard loads indicated in Appendix C should be considered. Thus a fender unit that is to be selected should be able to accommodate— (i) normal berthing energy for serviceability condition up to the rated capacity of the fender unit. and / or (B) the abnormal berthing case reaction (maximum fender reaction). to accommodate the characteristics of all vessels from smallest to largest. consideration should be given to separation of the berthing structure from the wharf facility so that accidental impact damage to the berthing structure does not necessarily prevent the continued use of the facility. 2(1) where qz = wind pressure. in kilopascals Accessed by CONNELL WAGNER on 05 Feb 2008 A www. Terrain category 2 (in AS/NZS 1170. Wind actions on vessels and floating structures may be designed using a wind pressure based on a 30 s gust rather than basic wind speeds due to 3 s gusts. 5.2) is generally appropriate for wind over exposed fetches. in square metres qz = wind pressure.4.2 Wind actions on a vessel or structure Wind pressure on a vessel or structure should be calculated from the following equation: q z = 0. in metres per second = V u for ultimate limit state = V s for serviceability limit state Wind loads on a vessel or structure should be calculated from the following equation: FD = CwD Aq z . 5. .87 times the relevant basic wind speed as specified in AS/NZS 1170.4. in kilonewtons Cw D = coefficient of wind drag (see Table 5.2. .0006 V 2 .4.1 Determination of wind actions Wind actions on wharves and wharf buildings and on stored materials or vehicles should be designed in accordance with AS/NZS 1170.4 WIND ACTIONS 5.2. .au Standards Australia .2(2) where F D = load in direction of wind.4.standards. 5.2(1). . 5.com. due to surface roughness of the water at design wind speeds.2) = projected area of element. These circumstances should be identified and appropriate design wind speeds determined. This is because floating structures have a delayed response to wind loads. The 30–second wind speed may be taken as 0.21 AS 4997—2005 There may be site-specific practices where large vessels may be directed to leave the berth during periods of high wind speeds.4. determined from Equation 5. in kilopascals V = design wind speed. 2.standards.2 Vessels (up to 10 000 t) Tubular piles 1.com.1 to 1. .au . in metres per second A = projected area of element.3 STREAM FLOW DRAG COEFFICIENTS Accessed by CONNELL WAGNER on 05 Feb 2008 Structure Drag coefficient (CsD ) Circular piles—Smooth 0. www.3) v = current velocity.5. .5 CURRENT ACTIONS 5.0 Piles—Heavy marine growth 1. the loads should be calculated from the following equation: Fs = 12 Cs D v 2 Aρ × 10 −3 .5–1.30 Vessels beam to current 0.2 TYPICAL WIND DRAG COEFFICIENTS Vessel or structure Coefficient of drag (Cw D) 1.2 Calculation For structures and vessels up to 10 000 t subject to currents.70 Circular piles—Rough 1.20 Square piles or beams with corners rounded 0.5.1 Design current The design strength of maritime structures should allow for the combined effects of tidal and/or river/estuarine flood currents.2 where Fs = current load.2 Rectangular members 2. 2 For vessels in excess of 10 000 t refer to BS 6349 for stream drag loads. 5.0 NOTE: For vessels in excess of 10 000 t refer to BS 6349 for calculation of wind loads. in kilonewtons CsD = stream flow drag coefficient (see Table 5.AS 4997—2005 22 TABLE 5.40 NOTES: Standards Australia 1 For more accurate assessment of the drag coefficient for the debris mat refer to AS 5100.00 1 Vessels bow to current 0.70–1.5.8 Debris mat 2. 5. in square metres ρ = 1026 kg/m 3 for sea water = 1000 kg/m 3 for freshwater TABLE 5.04 Square piles or beams with sharp corners 2. 5. sometimes resulting in overturning of the structure.8. or (ii) equal to top of structure.2.com. or (b) 500 mm. above which rising water levels will cause the structure to either submerge or fill. The negative lift is proportional to the flow velocity squared. a phenomenon known as negative lift should be considered. This phenomenon occurs as a result of currents passing under the floating structure and causing downward load on the leading edge of the structure. 5.6 DEBRIS ACTIONS For structures where a debris mat could form against the structure (most river estuarine situations).7 NEGATIVE LIFT DUE TO CURRENTS For floating structures in waterways subject to flood currents.5 m/s.2 m.23 AS 4997—2005 5.8 HYDROSTATIC ACTIONS Hydrostatic loads on structures result in lateral pressures and uplift on walls and floor slabs of maritime structures. This applies to both fixed and floating structures.standards. The load exerted by the debris mat may be calculated using Equation 5. All structures subject to flood debris should be designed for a minimum load of 10 kN per metre of structure. as appropriate. and not greater than 3 m. and can result in submersion of the leading edge of floating structures at moderate velocities. Negative lift phenomena should be examined where current velocities exceed 0.2 Tidal lag Hydrostatic effects on seawalls and other waterfront structures should consider tidal lag. In considering hydrostatic loads. the minimum water differential to be considered due to tidal fluctuations should be the larger of— (a) 1/3 of the spring tidal range. use of pressure relief systems cannot be relied on for preventing uplift. where the gross area of the mat (A) is measured normal to the direction of the stream flow.5. Ground anchors (passive or prestressed) may be included in stability calculations.1 Uplift stability Accessed by CONNELL WAGNER on 05 Feb 2008 Uplift stability of submerged or buried structures should be considered for the minimum weight for the structure and should be taken as the most severe of the following: (a) Structure empty In maritime conditions.8. 5. Tidal lag occurs when the level of ground water behind the wall lags behind the water level in front of the wall. www. due to the slower drainage characteristics of the wall backfill compared to tide level fluctuations in front of the wall. the highest design water level (flood level or storm elevated sea level) should be used. 5. the structure should be designed for a mat of thickness not less than 1. 5.au Standards Australia . (b) External water level is highest of— (i) maximum design water level plus half-wave height or more. In the absence of more detailed site-specific analysis on soil and wall permeability. joints. with corresponding significant wave heights (Hs) and wave periods (T s).1 General Waves can be classified as three types. Design storm events are generally described by the ‘significant wave height’ associated with the peak of the storm event.9 WAVE ACTIONS 5.standards.AS 4997—2005 24 5.3 Ground water Where rainwater run-off or other significant surface or subsurface flows could drain into the backfill of a seawall or other waterfront structures at a higher flow rate than could be expected to drain out through the subsoil or back-wall drainage system. resulting in high local differential hydrostatic pressures on the structure. Wave classifications are ‘swell-waves’.4. 5. (Such localized differential pressures have resulted in failures in seawalls.8. etc.9.4 Wave backpressure Backpressure on seawalls or other waterfront structures may result from the effects of waves on the wall penetrating the face of the wall through joints or cracks. (b) waves penetrating the fabric of the seawall (through cracks. The annual probability of exceedance of significant wave heights.au .2 Design wave heights Accessed by CONNELL WAGNER on 05 Feb 2008 The design strength of maritime structures should allow for the highest wave likely to occur on the structure over the selected design life and an annual probability of exceedance based on the function category of the facility. which may co-exist with the passage of a wave trough in front of the seawall. 5. resulting in a high water table behind the structure (up to the level of the top of the seawall or structure). Standards Australia www.8.) 5. for structures of various design lives and function categories.) which causes a locally high water table behind the wall. Consideration should be given to— (a) waves running up and overtopping the structure. are shown in Table 5. the design of the seawall or maritime structure should allow for a hydrostatic pressure based on a water table at the top of the wall or structure backfill.com.9. ‘wind-waves’ or ‘vesselwash’. The impact loads are of very short duration..2 For fully enclosed waters with maximum fetch lengths less than 10 km.standards. factored by 2. where slab soffit meets down-stand beam) can experience very high wave impact loads. Accessed by CONNELL WAGNER on 05 Feb 2008 5. normally calm waters—tropical Australian coastlines) to 2. taken to be the average of the highest 1% of all waves in the design storm event.9. 5. as follows: H 1 = fHs .0 (e. The design wave for structures should be equivalent to H 1.9.. structures containing re-entrant corners (e.4 should be taken as not below mean high water springs.4 ANNUAL PROBABILITY OF EXCEEDANCE OF DESIGN WAVE EVENTS Design working life (years) Function category Category description 1 50 100 or more 5 or less 25 (temporary works) (small craft facilities) (normal maritime structures) (special structures/ residential developments) Structures presenting a low degree of hazard to life or property 1/20 1/50 1/200 1/500 2 Normal structures 1/50 1/200 1/500 1/1000 3 High property value or high risk to people 1/100 1/500 1/1000 1/2000 NOTE: The design water levels used in combination with waves determined from Table 5. For open waters.) are subject to dynamic wave uplift loads. The uplift load may be approximated as the head of water corresponding to the wave crest as if the structure were not present. high energy waters—southern Australian coastlines). f should be taken as 1.50 (short narrow fetch) to 1. or from hydraulic modelling.g. . and extend over a limited area around the re-entrant corners.70 (longer wider fetch). with pressures several times the slowly varying pressure. where storm waves are likely to be superimposed on swells.0. .3 Design lateral wave loads The design of elements of structures should include design for the lateral loads of the waves impacting the structure.au Standards Australia .4 Wave uplift loads Structures where waves can travel under the soffit of the structure (jetty deck slabs under extreme wave conditions. In addition to this slowly varying dynamic pressure.70 (e.com. etc.g.25 AS 4997—2005 TABLE 5.. 5. This load may act upwards or downwards as the wave passes. www. low level landings. account should be taken of higher waves resulting from reflected waves interacting with incident waves.9. using recognized wave load formulae. Where the structures are close to reflective seawalls. for structures where the wave loads are a small part of the design loads. drainage out-falls.g. the following simplifications may be used: H 1 should be determined by applying a factor to the significant wave height for the design storm. The design wave conditions may be determined by more specific modelling or. f may be taken as 1. as well as loads applicable to the intermediate stages of construction.standards. a structure and its components should be designed to resist the loads applicable to the in-service performance requirements of the structure. but not superimposed.8. Where the area behind seawalls is subject to vehicle or other heavy loads. For seawalls with no associated wharf deck.12 COMBINATIONS OF ACTIONS 5. in accordance with Clause 5. Earth-retaining structures should be designed for a minimum surcharge load equal to the uniformly distributed load used for the design of the adjacent deck. designs should consider the details for resisting uplift loads (holding down bolts.stb = [0. (b) act simultaneously. etc.12. combinations of actions relating to maritime facilities should be considered. the following: (a) For combinations that produce net stabilising effects (E d. Where these impact loads are likely to occur. these high impact wave loads should be avoided by eliminating re-entrant corners (e. ultimate loads during storm or flood conditions.2 Stability The basic combinations used in checking stability should be as detailed in AS/NZS 1170. In addition. 5.11 LATERAL EARTH ACTIONS Lateral earth loads on waterfront structures and seawalls should be obtained by consideration of the soil parameters for the in situ soil and/or backfill against the structure. Consideration should be given to the effects of lateral water pressure in conjunction with lateral earth loads.com.AS 4997—2005 26 Structures where these loads are exerted can often accommodate such loads if other dynamic wave loads are adequately catered for and if the deck is structurally continuous over a larger area than the area exposed to impact pressures.1 General Unless otherwise specified. or (c) act simultaneously and are superimposed. the surcharge should be increased in accordance with Table 5. the minimum surcharge should be 5.12. Where possible.9G] Standards Australia permanent action only www..1.au .10 CONSTRUCTION AND MAINTENANCE ACTIONS Construction and maintenance actions on maritime facilities should take into consideration the probable use of cranes and other heavy loads required to construct and maintain maritime structures. Accessed by CONNELL WAGNER on 05 Feb 2008 Care should be exercised in defining combinations of actions to ensure the proper design action effect for actions that— (a) do not act simultaneously. reinforcement in the region of anchors.0 kPa.stb): E d. Sometimes construction and maintenance actions on over-water structures may exceed the service loads of the structure. Use of relieving slabs may be required to improve the stability of the earth-retaining structures. and as appropriate. Combinations specified in AS/NZS 1170 should be considered.) or the provision of pressure-relief systems or vents.g. 5. 5. use of flat plate concrete slabs on tubular piles) or by providing pressurerelief openings.0. 5. Fenv ] permanent and imposed actions and actions given in Clause 5.4 and/or Clause 5.com.standards.5 (c) E d = [0.12.4 and/or Clause 5. Fenv ] permanent actions and actions given in Clause 5.12.au Standards Australia .5 5.12. Fenv ] permanent and imposed actions.12.u .7W u .5Fb for normal berthing loads (b) S u = 1.12. water pressure. Q.12.12.5 Combinations of wind and wave loads The basic combinations should be modified for environmental loads due to wind and waves. ground water and earth pressures.5F gw for ground water (h) S u = 1.3.5F lp where the design water level could be exceeded (f) S u = 1.2G.12. S u .2F lp for static water pressure that is measured to the top of the structure (see Clause 5.1(b)) Su = 1.12. plus.u ultimate wave and wind www.12.dst = [1. S u .5 (b) E d = [1.1) Accessed by CONNELL WAGNER on 05 Feb 2008 (e) For submerged or partially submerged structures. Fenv ] permanent action and actions given Clause 5. S u .2G.u ultimate wave load (c) F env = W u .5Fe for earth pressures (g) S u = 1.6Q.7F wave.2G. where the design water height is at the top of the structure and cannot be exceeded: Su = 1.4 Combinations for berthing and stream loads.4 and/or Clause 5. 1.4 and/or Clause 5. water pressure.8. the following: (a) E d = [1.9G. S u .dst = [1. Fenv ] permanent actions and actions given in Clause 5.0.5 5.4 and/or Clause 5. Appropriate combinations may include one or a number of the following ultimate values: (a) F env = W u ultimate wind load (b) F env = F wave.5F lat for the minimum horizontal load (see Clause 5.2G.27 (b) AS 4997—2005 For combinations that produce net destabilising effects (E d. Appropriate combinations may include one or a number of the following factored values: (a) S u = 1.5Fs for ultimate stream flood flow and debris 5. as appropriate.dst): (i) E d.0. ground water and earth pressure The basic combinations should be modified for berthing and stream loads.3 Strength The basic combinations used in checking strength should be as detailed in AS/NZS 1170.5Fs ultimate wind and wave (d) F env = 0.12. F wave. 0.5 in (ii) E d.5F m for mooring loads (d) S u = 1.u for abnormal berthing loads (c) S u = 1.12.0Fb. S u .12. and actions given in Clause 5. adjacent to a tug vessel.s (l) Serviceability values of other actions.AS 4997—2005 28 5. That is. 5.) 5. or elements of structures.12. and from thrusters should be designed to cater for such loads. Standards Australia www. The magnitude of the repeated loadings when designing such structures. for fatigue performance should be determined from in-service cyclic actions. with a typical period of 2 s to 4 s.12. Appropriate combinations may include one or a number of the following using the short-term and long-term values as appropriate: (a) G (b) Q (c) Es (d) Fb (e) Fm (f) F lp (g) Fs (h) Fe (i) F gw (j) Ws (k) F wave. Design actions to be resisted are defined by AS 1170.com. in considering the application of AS 1170.4 it should be recognized that the Standard is particularly directed to the design of buildings and similar structures that are often significantly different to maritime applications. 5. as appropriate. as propeller wash from tugs can affect the safe operation of small craft.13 PROPELLER WASH Accessed by CONNELL WAGNER on 05 Feb 2008 The submerged elements of structures that are subject to propeller wash from passing vessels. NOTE: Structures in a waterway where waves constantly occur. Where tugs are likely to be operating routinely for assistance in manoeuvring large vessels. structures should be adequate to resist the ultimate wave loads as well as substantially smaller waves that result in constant cyclic loads leading to fatigue conditions. the siting of small craft facilities in such areas should be planned carefully. Nevertheless.7 Cyclic actions Structures that are subject to continuous wave action should be designed to cater for cyclic loadings.14 EARTHQUAKE ACTIONS 5. will experience 106 cycles per annum. (Propeller wash current speeds may be up to 8 m per second.6 Serviceability Combinations for the serviceability limit states should be those appropriate for the serviceability condition being considered.4.standards.1 General Design of structures for earthquake actions (E u ) have to ensure that adequate capacity exists for overall stability and member strengths and that the detailing of the structure will be sufficient for the expected movements of the structure.14.au . in particular tugs. Special consideration is. e. it should be easily accessible and. however. etc.) should be considered in the analysis (e. If suitable for the application. crane stability).2 Maritime structures Structures subjected to earthquake conditions often sustain less damage if the structure has a higher degree of shape regularity.. This slope stability effect may or may not occur during the peak earthquake accelerations. Specialist advice is recommended. Elements of a structure of high importance. buildings.au Standards Australia . if necessary.g. Accessed by CONNELL WAGNER on 05 Feb 2008 Adverse interactions between the structure and any supported structures (e.standards. The elements of lesser ductility need to be considered to ensure the displacements that would be expected to occur in the elements of higher ductility do not adversely affect the structure. (c) Response of adjacent structures and supported structures Consideration of the earthquake response of adjacent structures is required to ensure that conflict in responses does not result in the adverse contact. (e) Stability of reclamation and revetments The maritime structure being considered may be adversely affected by the failure of adjacent slopes due to an earthquake.. especially of sand layers.29 AS 4997—2005 5. If liquefaction is determined to occur. may be assigned a lower structural importance factor. e. (d) Structural importance factors Many significant maritime structures perform a postdisaster function or could be considered economically significant structures due to loss of function or cost of reinstatement. impact of wharf segments or loss of bridging elements to dolphins. www. then the effect of liquefaction on the structural analysis has to be included. limited ductility concrete deck supported on ductile steel piles.. The possibility of liquefaction. The structural ductility factor(s) selected needs to be able to be reliably achieved by the structure. cranes. simple load paths with multiple redundancies and simple connections.14. provided the elements will not compromise the remaining structure by its possible failure under a lesser effective design event.com. designed to absorb the earthquake energy while protecting the significant structure. or loss in contact. between the structures.. should be considered.g. These properties should be considered at the time of definition of the structural systems and carried through the design where at all possible. required for the possibly more adverse conditions where raking piles or squat members are founded on a stiff stratum. replaceable/repairable. Also of significant effect on maritime structures designed to withstand an earthquake are the following: (a) Structural ductility Often maritime structural design has elements with significant variation in member ductility. ductile response may be achieved by utilizing ‘fuse’ elements in the structure. (b) Soil conditions The soil conditions in the surface layers generally define the site’s dynamic stiffness and period regardless of the depth of actual founding stratum. which are not required for the general function of the structure. regardless of the depth. If a fuse element is used.g.g. In the latter case the initial capital cost is expected to be high. by design such that deterioration will not lead to failure. should be considered. the effect on concrete structures.2 DESIGN LIFE 6.com. where such cracking may then lead to accelerated corrosion of steel reinforcement. The design life of maritime structures will depend on the type of facility and its intended function (see Table 6. but may have reached a stage where further deterioration will result in inadequate structural capacity. and the design of maritime structures should include consideration of the requirements to withstand the aggressive environment while the structure remains serviceable.standards. Sections or components of the structure that have limited access or are inaccessible after construction should have a design life (with no maintenance) equal to the design life of the structure.1 GENERAL Maritime structures are generally sited in very aggressive environments for normal structural materials. the structure should have adequate strength to resist ultimate loads and be serviceable. This design life should be based on consideration of capital and maintenance expenditure.1). As well as determining loads for a facility. or. it is necessary to decide on a realistic design life for the structure. 6.2.au . At the end of the design life. Accessed by CONNELL WAGNER on 05 Feb 2008 TABLE 6. Particular care should be taken when considering design life and maintenance regimes for inaccessible members. This design life will depend on the owner’s requirements. The effect of extreme events on the structure’s durability should also be considered.AS 4997—2005 30 SECT ION 6 DURAB I L I T Y 6. in those cases when maintenance cannot (or is not expected to) be carried out.1 DESIGN LIFE OF STRUCTURES Standards Australia Design life Facility category Type of facility 1 Temporary works 5 or less 2 Small craft facility 25 3 Normal commercial structure 50 4 Special structure/residential 100 (years) www. For example. The designer should determine an appropriate maintenance regime consistent with the adopted design and materials that will achieve the design life.1 General Design life is defined as the period for which a structure or a structural element remains fit for use for its intended purpose with appropriate maintenance. Durability is to be realized either by a maintenance program. which may be heavily stressed and cracked in an extreme event early in the life of the structure. 2.31 AS 4997—2005 6.standards.1.au Standards Australia . (i) access the member with working scaffold for inspection and repair. Considerations include the ability to— service life of approximately 20 years.2. shapes and detail. and before (iii) prepare and apply protective coatings in situ to achieve required standard.2. (b) Reinforced concrete may not be a ‘lifetime’ maintenance-free material. (c) Improved performance of concrete structures will be achieved by a combination of the following: (i) Limiting design stresses in reinforcing steel.2 and 6. www. (iii) Improved performance concrete. (ii) Appropriate selection of member sizes. Whilst this Section deals with the use of concrete. and (iii) apply and maintain an adequate curing regime to the repair works. Considerations include the ability to— (i) access the member with working scaffold for inspection and repair.2.2.2.3. Reinforced concrete structures require regular condition inspection and maintenance of deteriorated sections. it does not preclude the use of other materials. (c) The maintenance strategy may allow the reinstatement of a protective coating/system before corrosion of steel begins.2. steel or timber are detailed in Clauses 6. (v) Closely controlled construction methods. (ii) remove and contain waste materials during repair works.2. steel and timber. (b) Paint coatings provide a repair/recoating is necessary. (ii) remove and contain waste materials during repair works. or for the deterioration of the steel member until replacement of the protective coating/system and/or the member is required. (d) (iv) Improved performance reinforcements. Accessed by CONNELL WAGNER on 05 Feb 2008 6.2. 6. Issues that should be considered when selecting concrete.2 Concrete The following items should be considered when selecting concrete as a material in the design of a maritime structure: (a) Concrete deterioration is usually a result of corrosion of reinforcing steel due to chloride ingress. 6.2.2 Material considerations 6.3 Steel The following items should be considered when selecting steel as a material in the design of a maritime structure: (a) Steel deterioration (corrosion) results from the breakdown of the protective coating or other protective system.com. Repairs may require the removal and replacement of deteriorated concrete and reinforcement.1 General The choice of materials to achieve the design life of a maritime structure should reflect the required design life and the agreed maintenance regime. Recent history has shown some maritime concrete structures experiencing significant premature deterioration as a result of an inappropriate selection of materials for the required design life.2.2.2. . Regular (annual or otherwise) inspection of the structure will permit early detection allowing the implementation of economic maintenance measures..au . forming an assembly of members within a structure. natural shrinkage due to drying timber will result in the need to tighten bolted connections during early years of the structure’s life.com. Early maintenance is generally recommended to prevent more significant damage.... (d) Where not in a continuously wet environment.10–30 years.2...5–10 years. Whilst a structure may have a prescribed design life of 25. without significant interruption to service operations. Maintenance will then be determined by the inspection results..... Members can usually be replaced easily within a structure to maintain the structural capacity.... as individual components deteriorate..4 Timber The following items should be considered when selecting timber as a material in the design of a maritime structure: (a) Individual timber members are relatively small.10–25 years. 6. species natural durability and preservative treatment. rot or attack by living organisms (decay fungi.. The following times to first maintenance can be expected: (i) Timber piles exposed to marine organisms . 50 or 100 years.................... operational conditions....AS 4997—2005 (d) 32 The preparation and recoating of steel in the marine environment is difficult and standards reached in the manufacturing process are not usually achievable in this environment. termites. (b) The service life of timber members will vary significantly depending on application..... local marine environments.. (b) a program of routine minor maintenance..... (iii) Timber decking exposed to weathering.... Considerations include— (i) the availability of skilled carpenters........ (ii) Timber piles not exposed to marine organisms ......2... (e) A maintenance strategy may allow for regular and frequent replacement of timber members throughout the design life..... and (c) a program of major maintenance... Standards Australia www.. and other factors will lead to maintenance requirements......... able to maintain the works over the structure’s design life. and (iv) the detailing and accessibility of bolted connections for ease of replacement during maintenance works. timber quality (grade)... (iii) the commitment of resources to regular inspection and maintenance of structures.. marine borers)....3 Maintenance All maritime structures deteriorate over time.... A typical maintenance program will include— (a) regular inspections.... Accessed by CONNELL WAGNER on 05 Feb 2008 6...2.. (ii) the future availability of suitable timber species and member sizes. (c) The deterioration of timber is usually by mechanical degradation..............standards. and the use of protective coatings to concrete members should be examined. Each concrete structure needs to be assessed individually to determine appropriate requirements for it to be durable. the encapsulation of prestressing tendons in watertight plastic conduits. concrete with a characteristic compressive strength above 50 MPa. e. as AS/NZS 4671 the design and performance requirements of recommendations made by these guidelines. Consideration should be given to the particular environment. However. The requirements for individual elements within a given structure will vary. at the outset. review all the alternative strategies available.3. The designer should. where stainless steel does not encompass this material type. Design of concrete maritime structures should focus on minimising the causes of premature corrosion of steel reinforcement as the repair of this deterioration may require major reconstruction of the affected elements and possibly pose restrictions on the use of the facility during repair/reconstruction. and normal criteria such as strength).standards. where a lower strength would satisfy design strength requirements. This is particularly evident in the splash zone.. The general advice given in this Standard regarding certain aspects of concrete maritime structures is offered to facilitate this individual assessment and should not be assumed to negate the necessity for carrying it out. as will the requirements for different structures. economical and slender structures.3 Structural concrete The following is recommended for structural concrete in a maritime structure: (a) Specifying special-class concrete. that is. in the use of AS 3600.3. particularly in compaction and curing. other problems including plastic shrinkage and thermal cracking may compromise durability.au Standards Australia .3 CONCRETE 6. unless proper construction techniques are adopted. There has been a trend for designers to specify high-strength concrete. (b) A minimum characteristic compressive strength (f′ c) of 40 MPa. The objective of the design for durable concrete structures is to reduce the opportunity for chlorides from sea water to cause the reinforcement to corrode. binder type and proportions as well as water-binder ratio. which can result from using the higher strength concretes. the detailing of the structure and the proposed maintenance regime. www.2 Structural design Accessed by CONNELL WAGNER on 05 Feb 2008 Structural concrete should comply with AS 3600. the use of stainless steel reinforcement.3. can lead to structures that are more highly stressed in flexure and are susceptible to chloride penetration through the wider crack widths. 6. the quality of the in situ concrete. the type and use of the structure. (The designer to specify particular requirements for the concrete. In addition. together with any applicable Engineering judgement will be required reinforcement is adopted. 6. For example. the use of plain concrete members.com.g. to reduce permeability and thus improve the durability of maritime structures.33 AS 4997—2005 6.1 General The predominant cause of deterioration of concrete maritime structures is corrosion of reinforcement and prestressing tendons. provided that the crack control provisions of AS 3600 for bar diameter and bar spacings. are satisfied. a drying shrinkage at 56 days not greater than 600 × 10 −6 mm/mm. 6.AS 4997—2005 (c) 34 General purpose Portland cement alone as the binder. either throughout the exposed section of the structure. the use of stainless steel reinforcement should be considered. over 500 mm deep 24 mm (28 mm preferred) Ties and ligatures 10 mm (12 mm preferred) In parts of concrete structures likely to be intermittently inundated. finishing and curing. to achieve the required strength and performance of concrete.2. (d) Cementitious content (Portland and blended cements) should be not less than 400 kg/m 3 . 2 When using blended cements particular attention needs to be paid to placement.4 Requirements for reinforcement Carbon steel reinforcement should comply with AS/NZS 4671 and be used and fabricated in accordance with AS 3600 and the following: (a) The total surface area of carbon steel reinforcement in maritime structures should be minimized to reduce the opportunity for corrosion by chloride-contaminated concrete. Curing should commence immediately after finishing horizontal surfaces.4429 Standards Australia www. NOTES: 1 It has been shown that for certain concrete mixes blended cements may improve the resistance to chloride penetration as well as slowing the rate of hydration of the binder. such as silanes. as appropriate. determined in accordance with AS 1012.standards. A smaller number of large diameter bars is preferable to a larger number of small bars.2 MINIMUM BAR DIAMETERS IN MARITIME CONCRETE STRUCTURES (CARBON STEEL) (b) Bar location Minimum diameter Slabs 16 mm Beams. siloxanes or other surface coatings.13. and be 16 mm diameter in slabs and 20 mm (preferably 24 mm) in beams. Accessed by CONNELL WAGNER on 05 Feb 2008 TABLE 6. reducing the potential for thermal cracking. then supplementary water curing should take place to 7 days.com. The use of penetrating chemicals for chloride inhibitors. or in combination with carbon steel reinforcement. (g) Concrete should be placed in watertight forms.au . If forms are stripped within 7 days. or a blended cement in accordance with AS 3972. (f) A maximum water to binder material ratio not more than 0.40. thoroughly compacted and protected from excessive temperature and wind evaporation. Minimum size bars for reinforcement should be in accordance with Table 6. to reduce water content whilst maintaining adequate workability. Small bars used for ties and ligatures should be not less than 10 mm diameter. up to 500 mm deep 20 mm (24 mm preferred) Beams.3. (h) All maritime concrete structures should be water-cured for at least 7 days and preferably 14 days under ambient conditions. splashed or sprayed with sea water. NOTE: The use of chemical curing compounds is not recommended on maritime concrete.4436 (316) or 1. Stainless steels equivalent to Grade 1. (e) For exposure classes C1 and C2. precludes the use of chemical curing compounds on maritime concrete. Super-plasticizers should be used. may be used in the more exposed locations. Stainless steel reinforcement should comply with BS 6744. (e) Cathodic protection of carbon steel reinforcement may be used to extend the design life of a maritime structure. provided the measures outlined below are taken. attachment plates). galvanized bolts. 6..35 AS 4997—2005 (316LN).5 Prestressing steel 6. For best performance. which can result in sudden tensile failures in concrete members.4301 (304) and Duplex 1. Stainless steel.3.4301 (304) is not recommended for use in areas in C2 exposure conditions). (In parts of maritime structures with exposure classification C2 (see Table 6.3). e. all steel within the member should be galvanized to prevent potential sacrificial corrosion of the galvanized coating.au Standards Australia . the corner bars in beam soffits.. bonding of all reinforcement cages by welding every bar intersection to facilitate the later introduction of cathodic protection of the reinforcement should be considered). fittings. although this should only be used when the designer is confident that the system will remain operational and will be routinely maintained. when used in combination with carbon steel reinforcement. bending and welding of reinforcement cages is complete. www. 1. the effect of chlorides on highly stressed strand and wire can produce unpredictable structural performance. (Grade 1. repairs to cut ends and breaks in the coating should be undertaken following the recommendations in AS/NZS 4680.4462 (2205) should be used. While the permanent compression in such concrete structures aids in reducing saltwater penetration through cracks. The ductility properties of stainless steel reinforcement should be ascertained when applying the structural design rules of AS 3600. In normal practice.g. it is important that the point of connection to normal steel reinforcement be deeply embedded. Galvanizing of reinforcement should be by the hot-dip process and an average minimum coating mass of 600 g/m 2 should be provided in accordance with AS/NZS 4680. (c) Galvanizing of carbon steel reinforcement may delay the onset of corrosion compared with normal (uncoated) carbon steel in a maritime environment.com. it is preferable for the galvanizing of reinforcement to be undertaken after all cutting.1 General The use of prestressed concrete in a marine environment requires additional consideration to be given to the protection of the highly stressed steel elements. Accessed by CONNELL WAGNER on 05 Feb 2008 If galvanized reinforcement is used. will provide the best overall result. and for thin reinforcing steel elements such as ties and stirrups. (unlike the staining and spalling behaviour of conventional steel reinforcement). When using galvanized reinforcement.g. If selective use is made of galvanized reinforcement or other components in concrete (e.standards. The use of galvanized reinforcement in conjunction with stainless steel is not recommended. The galvanizing provides corrosion protection to the base steel due to its resistance to the effects of reduction in the pH of the concrete mass (the carbonation effect) and its higher chloride tolerance compared to normal steel. Often these failures are unpredictable because the small cross-section of the high-strength steel will undergo substantial strength losses without any evidence on the concrete surface.3. the provision of an adequate cover of a good quality concrete. (d) Epoxy coating or other enveloping protection system for steel reinforcement is not recommended for concrete in a marine environment. as is necessary with normal carbon steel reinforcement. These effects include chloride corrosion and stress corrosion (embrittlement).5. with strand grouted within fully enclosed waterproof ducts of heavy-gauge inert materials (e.standards. non-prestressed carbon steel be used.. special consideration should be given to the effect of saltwater splash due to reflective waves off rear walls and rock revetments at the landward end of maritime structures. (i.7. These covers can vary within the deviation from specified position as prescribed in AS 3600 (that is. 3 mm–5 mm thick walled PVC or HDPE) can be expected to have substantial design life. together with the high availability of oxygen and presence of moisture in the concrete. Standards Australia www. where the concrete is alternately wet and dry.2 Post-tensioned members Post-tensioned members.g.5.au . but not in splash zone e.3. consideration should be given to minimizing the chloride ion content arising from aggregates and any admixtures used. However. surface sealants etc.3 of AS 3600.g. and all exposed soffits of structures over the sea C2 6. pore-blockers. It is recommended that in a marine environment where pre-tension wire or strand is used. from 1 m below water level up to 1 m above wave crest levels on vertical structures. in the splash (tidal) zone. TABLE 6. exposed to airborne salt spray. It is suggested that such non-prestressed reinforcement provide at least 40% of the total prestressed and non-prestressed reinforcement capacity.5.e. Reinforcement in concrete permanently submerged in sea water suffers only limited corrosion. and to the use of other preventative forms of future ingress of chloride ions (concrete additives for corrosion inhibitors.5 as appropriate.3 Pre-tensioned members When using pre-tensioned members stressed with unprotected carbon steel wires (protected only by concrete cover).6 Exposure classifications The exposure classifications given in Table 6.3. rapid corrosion is the consequence of chloride concentration and penetration.1 General The cover for low carbon steel bars should be not less than those shown in Tables 6.7 Cover to reinforcement 6.3 EXPOSURE CLASSIFICATIONS Exposure classification Accessed by CONNELL WAGNER on 05 Feb 2008 Exposure environment Reinforced or prestressed members Members permanently 500 mm below the seabed A2 Members permanently submerged 1 m below lowest sea water level to 500 mm below seabed level B2 Spray zone.). In this regard. the top side of deck slabs) C1 Splash zone.com. 6. This non-prestressed steel should be located in the most exposed section of the element to provide an early indication of chloride-induced corrosion.. within the appropriate tolerances).3..3. 6.AS 4997—2005 36 Exposed ends of prestressing steel should be cut back and protected with a suitable impermeable mortar to prevent ingress of water.4 and 6. 6.3.3 amplify those given in Table 4. especially designed concrete mixes. chemical corrosion inhibitor admixtures.5: 1 A design life of 25 years can be expected where the above tables are adopted for cover to reinforcement.2 Crack control Cracking in concrete maritime structures can lead to reinforcement corrosion as well as aesthetically unattractive structures.4 (except that minimum cover to steel should be 30 mm). 6. Table 6. the minimum cover given in the Tables above should apply.37 AS 4997—2005 TABLE 6. These may be combined in appropriate circumstances with cathodic protection systems. cover may be reduced by 25% from the values in Table 6. hydrophobic surface sealants (silanes) or other proven systems.3.com. with a design life of less than 5 years. limiting the widths of cracks under serviceability conditions can be achieved by designing structures with low stresses in the steel reinforcement.standards. 4 For temporary structures. 3 Where stainless steel AISI 1.4 MINIMUM COVER TO REINFORCING STEEL—STANDARD COMPACTION CONCRETE Minimum cover (mm) Exposure classification f′c = 40 MPa f′c = 50 MPa A2 40 30 B2 50 40 C1 70 50 C2 75 65 TABLE 6. 2 Where galvanized reinforcement is used. www. Additional measures that may be considered include the use of low corrosion rate reinforcement (stainless steel). or higher grade stainless steel reinforcement is used.4436 (316). To enhance durability.4 AND 6.5 MINIMUM COVER TO REINFORCING STEEL—INTENSE COMPACTION CONCRETE Minimum cover (mm) Exposure classification f′c = 40 MPa f′c = 50 MPa A2 35 30 B2 40 30 C1 60 45 C2 65 60 Accessed by CONNELL WAGNER on 05 Feb 2008 NOTES TO TABLES 6.au Standards Australia . Engineering judgement is required where a longer design life is required. Where stainless steel and carbon steel are used together in a member. The structures have to be also designed for other relevant limit states including both stability and strength.6 provides maximum recommended stress in carbon steel reinforcement for maritime structures in exposure classification C1 and C2. cover to steel may be reduced to 30 mm. cover to steel should not be reduced. use of additives or coatings such as organic or inorganic pore blocker concrete admixtures.7. galvanized reinforcement (in combination with other measures). The selection of the shape of steel members may not always be based on the most efficient system with regard to strength. Plastic or mild steel bar chairs should not be used. consideration needs to be given to grade selection. 6.au . surface finish and proper welding procedures.4. Metal items that protrude from the concrete surface should be insulated from steel reinforcement. or may be wrapped in purpose-designed materials applied after installation. Bar chairs comprising stainless steel or precast concrete blocks of high density and strength (preferably stronger than the concrete to be placed) are an acceptable method of supporting reinforcing steel.3. should be electrically isolated from the reinforcement cage. For example. Corrosion resistance of stainless steel increases with finer surface finishes. Grade 1. 6. as well as methods of installation and connection of steel members to prevent damage to pre-applied protective systems.3 Embedded Items Items that may be corroded by the saltwater environment should not be embedded in the cover zone. the decrease in steel durability after exposure to sea water should be considered when using carbon steel in the marine environment. etc.com. which if corroded. Prestressed concrete structures should be designed to remain uncracked throughout the service load range. exposed stainless steel fitments or bolts. but should be selected to allow the easy application and maintenance of protective coatings to allow improved durability. however. Tubular members can be protected with thick inert applied coatings in factory conditions. designers should consider methods that protect and maintain the steel members.standards.4 STEEL 6. During design.4. the tensile stress in steel reinforcement may be increased to the limits provided in AS 3600 for crack control. tubular members are easier to coat and wrap than flanged or angle sections.7. Corrosion of stainless steel in the form of surface discolouration (tea-staining) may be reduced by specifying high quality surface finish. so that galvanic cells between the reinforcing steel and the exposed metal cannot occur.4436 (316) or Grade 1.6 MAXIMUM ALLOWABLE REINFORCEMENT STEEL STRESS AT SERVICEABILITY LIMIT STATE db (mm) ≤12 16 20 ≥24 f s (MPa) 185 175 160 150 In elements with exposure classification A2 and B2. No potential corrosion path should be created by any material such as conduits or bar chairs.AS 4997—2005 38 TABLE 6. would compromise the concrete cover to the reinforcement. 6.1 General Accessed by CONNELL WAGNER on 05 Feb 2008 Steel is a suitable material for the construction of maritime structures.. Standards Australia www. For example.2 Stainless steel Where stainless steel is used in fabricated maritime structures.4462 (2205) should be selected for additional strength and corrosion resistance for maritime applications. . taking into account any future scour. However. exacerbated by wave action and seabed abrasion. If scratching or abrasion does not damage the protective surface oxide during installation or service then stainless steel can perform well.4 Wrapping systems The use of corrosion inhibiting fabrics (e. if the surface oxide is damaged then some air/oxygen should be available to allow the protective film to repair.. and the implementation of a suitable inspection and test procedure to assess the effectiveness of the applied system. 6. and site drilling and bolting can cause damage to the protection system.4.4.4. petrolatum-tape) to wrap piles or substructure members is a suitable method for protecting members exposed to an aggressive environment (splash and spray zone).5 Painting systems The use of inert. 6.4 Steel protection systems 6. Stagnant conditions may also be a source of microbiologically influenced corrosion.4. which may result from propeller wash. concrete jackets) is a suitable method of providing long-term protection to members such as steel piles. salt.3 Applied coatings The application of thick (1 to 5 mm thick) inert materials (e.. Paint systems should be able to be reapplied to old surfaces. the thickness of the coating system. 6. AS/NZS 2312 and AS/NZS 4673. must be repairable. at the time of construction and erection. is a suitable method for protecting piles or substructure members in aggressive environments. are suitable for the protection of steel structures in the splash zone.39 AS 4997—2005 Stainless steel should be used cautiously in anaerobic conditions. Consideration should be given to the type of coating selected. Elements permanently buried in the seabed or permanently immersed in sea water.6. 6. urethane. 6. the protective systems should be capable of repair/replacement during scheduled maintenance.4. high build paint systems. and the relevant standards relating to manufacture and rolling and milling of steel products as listed in AS 4100.3 Material requirements Steel structures should comply with AS 4100.g.7).4.4. under factory conditions. Damage caused by corrosion in the various marine environments can be attributed to varying physical processes such as rapid oxidation in the wet. polyethylene etc). surface preparation.4. to allow for repair and maintenance. as well as wear and tear from maritime operations (chafing.4. cutting and welding steel members. such as epoxy paints. For further information refer to AS/NZS 1554. HDPE pipe.standards. at the end of the specified maintenance-free period.g. flexing). generally have low corrosion rates and an annual corrosion allowance can account for the corrosion of the element (see Clause 6. Damage caused to steel protection systems. www.4.4. surface conditions. Normal activities such as installing piles. stream flow or similar.2 Jacket systems Accessed by CONNELL WAGNER on 05 Feb 2008 The encapsulation of steel members inside protective jackets (e. These various forms of corrosion and damage require different protection systems. In addition.1 General Steel surface protection systems have been developed for various structural steel elements and corrosion environments. the method of application. such as mud. The jackets must extend a safe distance below seabed level. which can attack many metals including stainless steels.4.au Standards Australia .com. 6.4.g.4. 7. Where a corrosion allowance is to be used to protect submerged steel members.10 NOTE: The influence of ‘microbiologically induced corrosion’ (in anaerobic conditions below seabed) or ‘accelerated low water corrosion’ (about low water level) should be examined.4. but exposed decks should have minimum thickness of 6 mm.6 Metallic coatings Thin metal coatings and hot dip galvanizing are suitable methods for protecting steel in some environments.4.com. protected on the inside face by a suitable paint coating system may be reduced to 4 mm. (d) Hollow members (tubular piles. Sealed tubular members may have a wall thickness of 4 mm.AS 4997—2005 40 6. (c) All steelwork should be designed to be free-draining. (b) The minimum bolt size for structural connections should be 20 mm for carbon steel and 12 mm for stainless steel. 6.4. however.6 Cathodic protection Cathodic protection for steel structures is only applicable for parts of the structure permanently immersed in water. Standards Australia www.4. Tie rods should be of similar diameters. unless test data extending over an acceptable duration validates a lower rate for a particular location. Accessed by CONNELL WAGNER on 05 Feb 2008 Designers should consider the following: (a) Structural members exposed on both faces should not have a web or flange thickness less than 8 mm. corrosion rates should not be less than those tabulated in Table 6. such systems are not suitable where the surfaces will be subject to immersion or driven spray. Cathodic protection should be installed in accordance with AS/NZS 2832. 6.5 Member sizes Steel members should be selected to be robust and have adequate reserve of strength to allow for corrosion and unpredicted loads for structures with a design life in excess of 5 years.7 CORROSION ALLOWANCE FOR STEEL SECTIONS (PERMANENTLY SUBMERGED IN SEA WATER) Exposure classification Condition Annual corrosion rate (mm) Mild Permanently buried in seabed (see Note) 0. due to the solubility of most metal corrosion products.05 Strong Tropical/Subtropical water (north of 30°S) 0. 6.7 Corrosion allowance for permanently submerged steel Where no protection systems are to be applied. These influences may produce corrosion rates significantly higher than those above.au . TABLE 6. rolled hollow sections) should be sealed to prevent corrosion on the inside face.g. e.. with no pockets that may trap water or sediment. Plate thickness on pontoons. protection of the steel may be provided by providing an allowance for corrosion and subsequent loss of steel cross-sectional area. in a steel section buried below the seabed or a section permanently submerged.4.standards.01 Moderate Cold water (south of 30°S) and near the mud line 0.4. Timber for maritime structures should generally be hardwood timber of Natural Durability Class 1 or 2.1).. 6. small craft facilities. stringers. www. it is desirable to have the section of pile in the water column free of interruptions to the bark (e.5.3 Timbers above water level Timber members located above the level of high tide are not at risk of marine borer attack. Caution should be exercised to avoid stray currents from cathodic protection systems affecting moored vessels and unprotected structures. or timber can be effectively used in conjunction with other materials to provide economic. in accordance with AS 5604. or where currents from vessels will not negate the effect of the system.1).standards. where branches may have been trimmed) as these areas provide a flaw in the pile’s natural protection to marine organisms.au Standards Australia .com. Impressed current cathodic protection may be used where the system is likely to be well maintained and where stray currents do not interfere with the protection system. they should be of a species resistant to fungal attack due to standing fresh water and termite attack.. Generally timber would not be used as the principal structural medium for a facility with a design life greater than 25 years and decks classed above Class 10 (see Table 5. jetties and similar). sacrificial anodes should be used with or without a protective paint system.41 AS 4997—2005 Where cathodic protection is used and regular maintenance of the structure is unlikely.5.5 TIMBER 6. Timber may be used for fendering systems and other wearing surfaces. 6. Syncarpia glomulifera (Turpentine) or alternatively may be treated with preservative impregnation and/or coatings/sheathing/jacketing (impermeable).g. 6.2 Immersed timber Accessed by CONNELL WAGNER on 05 Feb 2008 Timbers in contact with tidal saltwater should be selected for their natural resistance to marine borer attack e. turned down at each side (see Figure 6. headstocks. and durable structures. Similarly. Where paint systems are used. piers. Such preserved timber should not be cut or drilled where it will be immersed. as well as for fender piles on structures predominantly constructed from concrete and/or steel. Where Turpentine timber piles are used. however. To minimize the risk of marine organisms attacking the exposed inner wood of cut or drilled timber. To alleviate the normal problems of fungal attack caused by rainwater or other sources of moisture on timber. Substructure timbers should be protected from standing fresh water by a layer of aluminium sarking spiked to the top face of the timber.g. a suitable barrier material should be applied. timber piles below high water level should not be cut or drilled.1 General Timber has many applications in maritime structures. bearers and decking. Timber may be used for the construction of the total structure including piles. particularly in lighter duty recreational facilities (waterfront boardwalks. Preservation of timber for use in piles or other structures below water level should be in accordance with AS 1604. to resist marine organisms. the cathodic protection should be designed to provide protection as the paint system deteriorates. concrete decks may be used on timber resulting in durable and economic structures.5. To reduce trip hazards. sheathing. A steel ring should be fitted around the top of the pile to minimise splitting after installation. Piles in such situations should employ coatings.5 Finishes Increased protection from environmental deterioration may be achieved by the application of coatings to timber.1 SARKING DETAILS Exposed timber pile tops should have waterproof caps moulded to the top of the trimmed pile. The topside of the timber should be rough sawn to reduce slip hazard when wet. are effective as decay inhibitors. including paint finishes. etc.au . along with timber end-grain should be protected by application of moisture repellent and decay inhibiting preservatives. Accessed by CONNELL WAGNER on 05 Feb 2008 Interfaces of joints and drilled holes. it is necessary to ensure that trip hazards will not be caused by differences in plank thickness or warping due to drying. epoxy coatings. Standards Australia www. decking timbers should generally be machined on the underside to ensure uniform thickness. Deck planks should be ‘back sawn’ sections and laid with the timber’s ‘heart’ side as the underside of the deck.5. NOTE: Where a structure is installed adjacent to oyster leases or sensitive fishing grounds. which may contain diffusing properties to penetrate below the wood’s surface.standards. 6. jacketing.AS 4997—2005 42 FIGURE 6. in situ preservative applications or by wrapping the member with protective wrapping materials.com. Other vertical timber sections should where possible be cut at an angle to facilitate shedding of moisture.4 Decking In the design of timber decks used for pedestrian access.5. chemically treated piles should not be used. Products containing copper naphthenate chemical. 6. 43 AS 4997—2005 APPENDIX A CONTAINER WHARF DECK LOADINGS A1 GENERAL Container wharf deck loadings relate to the wharf-side loads from transporting and stacking containers for loading/unloading container ships.standards. which represent typical loads and dimensions. In the absence of more specific equipment specifications.com.4 m wide. A2 CONTAINER STACKING Containers may be stacked on the apron beside a vessel while awaiting transport or loading. loads and dimensions given in Table A1. stacked 2 high. Concentrated corner loads are as given in Table A1. A3 CONTAINER TRANSPORT Forklift trucks and reach-stackers to transport 40 ft containers have the following wheel loads: Accessed by CONNELL WAGNER on 05 Feb 2008 LADEN Maximum front wheel load 300 kN (4 No) Maximum rear wheel load 100 kN (2 No) (Tyre pressure of 750 kPa) UNLADEN Maximum front wheel load 100 kN (4 No) Maximum rear wheel load 200 kN (2 No) The arrangement of such loads is shown in Figure A1.2 m long and 2. Adequate provision for these effects should be allowed. Straddle carriers have a maximum wheel load of 150 kN and an arrangement as shown in Figure A2. TABLE A1 STACKING LOADS FROM CONTAINERS ON WHARF APRONS Storage method Load (kN) Dimensions of loaded area (mm) Single container 230 150 × 150 Line of containers 380 150 × 400 Block of containers 750 400 × 400 NOTE: This is for 40 ft containers that are 12.au Standards Australia . which may be stacked several containers high. supported at each corner. www. The loads do not reflect loads from storage of containers in container yards. as such storage is specific to each port. should be applied to design in order to reasonably accommodate container operations. These loads do not include dynamic effects. longitudinal loads into tie-down anchors and transverse loads into the rails). Crane weights and corner loads vary with crane capacity. however. Bogie arrangements with up to 12 wheels per corner. The length of applied load will depend on the crane design and conditions. operational and extreme wind conditions. The CQC loading on the crane rail (and so to the wharf structure) varies widely with each specific crane installation. a nominal loaded length of 8 m for one leg of the CQC will accommodate the typical corner loads shown in Figure A3 under most conditions. Travel stop buffer loads should also be considered. Special attention should be given to CQC loads in cyclone areas.com.1 m centres) can reduce the design load to 500 kN/m. rail gauge. with a rail gauge commonly ranging between 15m and 30m (see Figure A3). these loads will have to be assessed for each installation.standards. with a maximum length of 12 m (12 wheels at 1.au .AS 4997—2005 44 FIGURE A1 FORKLIFT TRUCK AND REACH STACKER WHEEL ARRANGEMENT FIGURE A2 STRADDLE CARRIER WHEEL ARRANGEMENT A4 CRANE RAILS Accessed by CONNELL WAGNER on 05 Feb 2008 Container quay cranes (CQCs) operate on crane rails set into the wharf deck. with provision for higher loads in tie-down zones (increased wheel loads. Application of this load into the wharf (rail) may be regulated by the number and spacing of the wheels at each corner. uplift loads. parallel to the wharf quayline. A general design load of 750 kN/m will accommodate most CQC loadings. Standards Australia www. standards.45 AS 4997—2005 DIMENSIONS IN METRES Accessed by CONNELL WAGNER on 05 Feb 2008 FIGURE A3 TYPICAL CONTAINER QUAY CRANE CONFIGURATION FOR POST-PANAMAX VESSELS www.com.au Standards Australia . (j) vessel dimensions. it is recommended to follow these guidelines for design of fender systems for vessels over 10 000 DWT. Unless more specific design practices apply for a particular port facility. accommodation for bulbous bows. one of which is presented in this Appendix (see Figure B1). (i) procedure to determine and report the performance of pneumatic fenders. Accessed by CONNELL WAGNER on 05 Feb 2008 The PIANC Guidelines provide a comprehensive coverage of all aspects of fender design. ‘Guidelines for the Design of Fender Systems: 2002’. B2 GENERAL A widely accepted guideline for design of fender systems for commercial shipping is provided by PIANC International Navigation Association.au . (e) fender selection.com.AS 4997—2005 46 APPENDIX B BERTHING ENERGIES AND LOADS B1 SCOPE This Appendix provides a commentary on methods for determining berthing energies and corresponding reaction loads due to vessels berthing at a wharf or structure and for the design of fender systems. (f) whole of life considerations. (d) detailed fender design. flexible dolphins and berthing beams. (b) fender geometry: spacing. B3 APPROACH VELOCITY The PIANC Guidelines presents two methods for determining design approach velocity. including— (a) development of the berthing model (contact with single/multiple fenders). (h) procedure to determine and report the performance of marine fenders. Standards Australia www. Report of Working Group 33 of the Maritime Navigation Commission. and (l) guidelines for specification writing. (c) description of fender systems. (k) selection of fender size—case studies. (g) special cases—vessel class.standards. vessel to vessel. com. and it is considered that maximum velocity for berthing may be taken as 0. (e) Difficult berthing—exposed. Accessed by CONNELL WAGNER on 05 Feb 2008 The impact data shows low approach values for large vessels. which may be exceeded in adverse conditions. For approach velocities for vessels below 1 000 t. The velocities assumed in Figure B1 assume that all berthings are tug-assisted. (b) Difficult berthing—sheltered. the velocity indicated for vessels below 10 000 t are high.6 m/sec. Caution is required when applying the velocity values at these extremes of Figure B1. (d) Good berthing—exposed. (1977) Design berthing velocity (mean value) as a function of navigation conditions and size of vessel) Figure B1 distinguishes five navigation conditions.standards. (c) Easy berthing—exposed. www. as follows: (a) Good berthing—sheltered. guidance in this range is presented in Table B1.47 AS 4997—2005 FIGURE B1 BERTHING VELOCITIES—VESSELS > 1000 t (Source: Brolsma et al. Similarly.au Standards Australia . 0 knot.20 Moderate 0.35 NOTES: 1 ‘Mild’ exposure has current speeds less than 0.30 Moderate 0.25 Mild 0. This load should be factored to account for— (a) manufacturing tolerance (5–10%).AS 4997—2005 48 TABLE B1 BERTHING VELOCITIES—VESSELS < 1000 t Vessel class Tonnage range Exposure conditions1. Standards Australia www. and (d) temperature.5 knots and 1.2.15 Moderate 0. and wave heights less than 10% of the moulded draft of the design vessel.30 Mild 0.au . or fair weather wind speeds between 10 knots and 15 knots.25 Severe 0. or fair weather wave heights between 10% and 20% of moulded depth of vessel. 2 ‘Moderate’ exposure has current speeds between 0. fair weather prevailing wind speeds less than 10 knots.30 Mild 0. Fenders should be specified to be pre-conditioned before installation to avoid higher than expected reactions on the first maximum compression by a vessel.20 Severe 0.standards. (c) angular compression. B4 FENDER REACTION LOADS Accessed by CONNELL WAGNER on 05 Feb 2008 The reaction load from fenders should be determined from the manufacturer’s performance charts.5 knots.3 Vn (m/sec) Private vessels Private vessels Commercial charter/ cruise vessel Ferries Ferries Up to 10 t Over 10 t Up to 1000 t Up to 100 t Over 100 t Mild 0.40 Mild 0.30 Severe 0. Performance figures are usually valid for fenders that have been pre-conditioned by compression to the rated values.com.20 Moderate 0.25 Moderate 0.35 Severe 0. (b) berthing/compression speed. 3 ‘Severe’ exposure is when the environmental conditions exceed any of the current wind or wave conditions for a moderate exposure. The PIANC Guidelines discuss all these aspects of fender reaction forces.25 Severe 0. au Standards Australia . these can vary from 20% for UHMWPE to 40% for timber. depend on fender face material. vertical and horizontal.49 AS 4997—2005 B5 LOADS ASSOCIATED WITH BERTHING IMPACTS Associated with berthing impact loads are longitudinal and vertical loads as the vessel slides along the face of the fender and heaves or rolls under the reaction of the impact.standards. These lateral loads are calculated as the maximum impact reaction load (on the fender system or structure).com. www. Accessed by CONNELL WAGNER on 05 Feb 2008 Typical friction factors. factored by the coefficient of friction between the sliding surfaces. in any direction from the forward arc from the wharf. These forces are a result of vessels using bollards to slow vessels down or to assist in turning vessels while using rudders and propulsion systems. Mooring forces should consider loads applied +45° and −15° to the horizontal plane. as determined by Table C1. Refer also to OCIMF papers or BS 6349 for calculation of wind and current loads on moored vessels. Where vessels may be exposed to conditions other than mild. the bollard capacity should by 25%.AS 4997—2005 50 APPENDIX C MOORING LOADS Vessels berthed at structures will exert loads through fenders reactions and through mooring lines. as well as manoeuvring forces when vessels are berthing and departing berths. resulting from loads acting on the vessels. current and wave forces on the vessel.com. These loads include wind. Mooring forces from vessel manoeuvring loads should be considered. The design action used in the structural design should be equal to the rated capacity of the bollard or mooring cleat. TABLE C1 Accessed by CONNELL WAGNER on 05 Feb 2008 MOORING FORCES FOR SHELTERED CONDITIONS Standards Australia Vessel displacement (tonnes) Bollard capacity kN Up to 50 50 50 to 200 100 200 to 1000 200 1000 to 10 000 300 10 000 to 20 000 500 20 000 to 50 000 800 50 000 to 100 000 1 000 100 000 to 200 000 1 500 Above 200 000 2 000 www. Refer to Section 5 for calculation of wind actions on a vessel.au . The design lateral load on an individual mooring point should be 20% more than the evenly distributed component of load established from the geometry of the moored vessel. recognition should be given to the variability of stiffness of the lines connecting the vessel to the several mooring points.standards. In determining the wind load from a vessel on any individual structure. Accessed by CONNELL WAGNER on 05 Feb 2008 51 NOTES AS 4997—2005 . Accessed by CONNELL WAGNER on 05 Feb 2008 AS 4997—2005 52 NOTES . The requirements or recommendations contained in published Standards are a consensus of the views of representative interests and also take account of comments received from other sources. limited by guarantee. This role is vital in assisting local industry to compete in international markets.Standards Australia Standards Australia is an independent company. Australian Standards are kept under continuous review after publication and are updated regularly to take account of changing technology. either downloaded individually from our web site. For more information phone 1300 65 46 46 or visit Standards Web Shop at www. which prepares and publishes most of the voluntary technical and commercial standards used in Australia. International Involvement Standards Australia is responsible for ensuring that the Australian viewpoint is considered in the formulation of international Standards and that the latest international experience is incorporated in national Standards. Electronic Standards All Australian Standards are available in electronic editions.standards. For further information on Standards Australia visit us at www.com. governments. Standards Australia is recognized as Australia’s peak national standards body. These standards are developed through an open process of consultation and consensus. or via On-Line and DVD subscription services.au Australian Standards Australian Standards are prepared by committees of experts from industry. Through a Memorandum of Understanding with the Commonwealth government. in which all interested parties are invited to participate. They reflect the latest scientific and industry experience. Accessed by CONNELL WAGNER on 05 Feb 2008 Standards Australia represents Australia at both ISO (The International Organization for Standardization) and the International Electrotechnical Commission (IEC).standards. consumers and other relevant sectors.au .org. au Internet www.standards.com.au ISBN 0 7337 6858 X Printed in Australia .au Customer Service Phone 1300 65 46 46 Fax 1300 65 49 49 Email
[email protected] by CONNELL WAGNER on 05 Feb 2008 GPO Box 476 Sydney NSW 2001 Administration Phone (02) 8206 6000 Fax (02) 8206 6001 Email mail@standards. Accessed by CONNELL WAGNER on 05 Feb 2008 This page has been left intentionally blank. .