c5-10 Structural Steelwork

NPQS C5-10 Structural SteelworkNational Productivity and Quality Specifications (NPQS) C5-10 Structural Steelwork 1 Version 1.0 NPQS C5-10 Structural Steelwork CONTENTS Page 1. 1.1 1.2 1.3 1.4 1.5 2. 2.1 2.2 3. 3.1 3.2 3.3 3.4 3.5 3.6 4. 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 5. 5.1 5.2 5.3 5.4 GENERAL Scope Related Sections Standards and Technical Reference Trade Preambles Definitions PERFORMANCE REQUIREMENTS Design Brief Loading During Construction MATERIALS Steel Sections/Elements Welding Consumables Fasteners Profiled Steel Decking Protective Finishes Grout WORKMANSHIP General Storage and Handling Fabrication Bolting Welding Permitted Deviations (PDs) of Fabrication Erection Permitted Deviations (PDs) in Erection VERIFICATION AND SUBMISSIONS Submission Procedural Trial and Trial Assemblies Inspection Non-Destructive Testing of Welds 3 3 3 3 5 6 8 8 8 9 9 10 10 11 11 11 13 13 13 13 15 17 20 27 28 34 34 36 36 36 2 Version 1.0 NPQS C5-10 Structural Steelwork 1. GENERAL Read with the General Requirements section, and all other contract documents. 1.1 Scope This section covers the requirements for the fabrication and erection of normal structural steelwork in buildings. It does not cover the use of stainless steel in special structures. 1.2 Related Sections Read this work section in conjunction with the relevant requirements of the other work sections as follows: C5-20 Protective Works for Structural Steelwork 1.3 Standards and Technical Reference 1.3.1 Standard Unless otherwise agreed by the SO, ensure all of the Works comply with the relevant requirements of the Standards and Codes listed below or referenced in the body of the Specification. Alternative Standards and Codes may be proposed for approval by the SO, provided it can be demonstrated that the alternative Standards and Codes comply with the requirements of the standards specified. All Standards and Codes quoted are the current version, unless specific year references are noted. Singapore Standards SS 470 Hot-finished structural hollow sections of non-alloy and fine grain structural steels Part 1: Technical delivery requirements Part 2: Tolerances, dimensions and sectional properties SS 503 Cold formed welded steel structural hollow sections Part 1 : Technical delivery requirements Part 2 : Tolerances, dimensions and sectional properties Other Standards ANSI/AWS D1.1-02 ASTM E165 ASTM E709 ASTM E747 BS EN ISO 8981 BS EN ISO 1461 BS EN 10024 BS EN 10025 Structural welding code. Steel Standard test method for liquid penetrant examination Standard guide for magnetic particle examination Controlling quality of radiographic testing using wire penetrameters Mechanical properties of fasteners made of carbon steel and alloy steel. Bolts, screws and studs Hot dip galvanised coatings on fabricated iron and steel articles. Specifications and test methods Hot rolled taper flange I sections. Tolerances on shape and dimensions Hot rolled products of non-alloy structural steels. Technical delivery conditions 3 Version 1.0 NPQS C5-10 Structural Steelwork BS EN 10029 BS EN 10051 BS EN 10113 Tolerances on dimensions.0 . wide flats and sections Part 1: General requirements Part 2: Plates and wide flats Part 3: Sections BS EN 10210 Hot finished structural hollow sections of non-alloy and fine grain structural steels Part 1: Technical delivery requirements Part 2: Tolerances. Structural steel equal and unequal leg angles. Tolerances on dimensions and shape Hot-rolled products in weldable fine grain structural steels Part 1: General delivery conditions Part 2: Delivery conditions for normalised/ normalised rolled steels Part 3: Delivery conditions for thermomechanical rolled steels BS EN 10137 Plates and wide flats made of high yield strength structural steel in the quenched and tempered or precipitation hardened conditions Part 1: General delivery conditions Part 2: Delivery conditions for quenched and tempered steels Part 3: Delivery condition for precipitation-hardened steels BS EN 10155 BS EN 10163 Structural steels with improved atmospheric corrosion resistance. sheet and strip of non-alloy and alloy steels. dimension and mass Structural steel I and H section. Specification for hot rolled sections Podger spanners ISO metric precision hexagon bolts. Technical delivery conditions Specification for delivery requirement for surface condition of hot rolled steel plates. screws and nuts – specification Metal washers for general engineering purposes High strength friction grip bolts and associated nuts and washers for structural engineering (metric series) Specification for rigging screws and turnbuckles for general engineering lifting purposes and pipe hanger applications 4 Version 1. dimensions and sectional properties BS EN 10219 BS EN 10279 BS EN 10034 BS EN 10055 BS EN 10056-1 BS EN 10056-2 BS 4-1 BS 2583 BS 3692: BS 4190 BS 4320 BS 4395 BS 4429 Cold formed welded structural hollow sections of non-alloy and fine grain steels Hot rolled steel channels. shape and mass for hot rolled steel plates 3mm thick or above Specification for continuously hot-rolled uncoated plate. screws and nuts – specification ISO metric black hexagon bolts. Tolerance on shape and dimensions Hot rolled steel equal flange tees with radiused root and toes. Dimensions and tolerances on shape and dimensions. Tolerances on shape. Dimensions Specification for structural steel equal and unequal leg angles. Tolerances on shape and dimensions Structural steel sections. 1. fabrication and erection. 1. 2002.4. Part 1: Specification for compressible washers Part 2: Specification for nut face and bolt face washers BS 7668 Weldable structural steels. 5 Version 1.4 Trade Preambles 1.0 . refer to the latest edition or the approved substitution for the relevant clauses. paying attention to the safe erection of structural steelwork in accordance with BS 5531.3.2 Shop Drawings Engage qualified and experienced personnel to prepare coordinated shop drawings for the fabrication and erection of the steelwork. Part A1: Visual assessment of surface cleanliness BS 7419 BS 7644 Specification for holding down bolts Direct tension indicators. Engage a PE (civil) to develop the design of the connections based on the structural design drawings.NPQS C5-10 Structural Steelwork BS 4604 BS 4921 BS 4933 BS 5531 BS 5950 Use of high strength friction grip bolts in structural steelwork (metric series) Specification for sherardised coatings on iron and steel ISO metric black cup and countersunk head bolts and screws with hexagon nuts Code of practice for safety in erecting structural frames Structural use of steelwork in building Part 1: Code of practice for design.2 Temporary Works Engage a PE to plan.1. design and supervise any necessary temporary supports to ensure the structural steelwork is stable throughout the construction. UK’s National Structural Steelwork Specification (NSSS).1 Contractor’s Submissions and Proposals Connection Design Develop the connection design when required as indicated in the PSD. Rolled and welded sections Part 4: Code of practice for design of floors with profiled steel sheeting BS 7079 Preparation of steel substrates before application of paints and related products. Hot finished structural hollow sections in weather resistant steels In the event that the Standards or Codes are partially superseded or become obsolete.4.2 Technical Reference When carrying out the works.1.4. 4th Edition. take guidance from the following technical reference: a. 1. 1.1 1.4. Rolled and welded sections Part 2: Specification for materials. including all on site weld tests where applicable. Provide evidence of personnel’s past experience and certificate to the SO for acceptance prior to commencement of the Works.10 for guidance.3.4. Any instruments or other equipment required checking the accuracy and quality of the works.NPQS C5-10 Structural Steelwork 1.3 1.4. 1. make available to the ITA the following: a. Shop 6 Version 1. Design Drawings Drawings showing the dimensioned layout of the steel structure with the size and material grades of all members.1 Qualifications Steel Fabricators Engage steel fabricators who are accredited under the Structural Steel Fabricators Accreditation Scheme of the Singapore Structural Steel Society for the fabrication works. 1. 1.5 Accredited Laboratory Engage a laboratory accepted by the SO and accredited under the Singapore Laboratory Accreditation Scheme (SINGLAS) to carry out tests and checks as required by this Specification.6 Independent Inspection and Testing Agency (ITA) Appoint an independent Inspection and Testing Agency (ITA) when required as indicated in the PSD. 1.1 Section 4 Part C. clause 1.4. Alternatively.3. In either of the above cases.4. 1. 1. the forces to be developed in their connections and any cambers etc.0 . Drawings showing all necessary information to fabricate the structural steelwork. b. All requested documentation and a detailed programme to allow the ITA to discharge its duties and to witness significant stages in the fabrication and erection process.3.3 Welder Qualification Submit evidence of welders’ competence to the to undertake the specified work. Refer to the PSD for the required grade of the fabricator.4. The welder’s test is to be conducted and certificates are to be issued by the Independent Inspection and Testing Agency.4. the SO may engage the ITA separately.4 Quality Control Plan Submit and work to a quality control plan as agreed with the SO.4.5 Definitions a. including the piece markings with the b. from which shop drawings are made.2 Supervisors All structural steelwork and associated works are to be undertaken and supervised by appropriately experienced personnel. Refer to the General Requirements section.4. The welders are to be tested to meet the requirements of ANSI/AWS D1. shaping. tapering. d.0 .NPQS C5-10 Structural Steelwork Drawings c. Forming. Reaming Faying Surfaces location in the structure. or enlarging a hole with a reamer. Surfaces which are tightly or closely fitted. 7 Version 1. 2 Loading During Construction Ensure that the steelwork is adequately braced or restrained to withstand all loadings liable to be encountered during construction without inducing excessive stresses. deflections or distortion in the structure.0 .1. 2.1 PERFORMANCE REQUIREMENTS Design Brief When carrying out design as described in Clause 1. 8 Version 1.4. Design the connections based on forces given in the design drawings. 2.NPQS C5-10 Structural Steelwork 2. ensure the design conforms to the requirements of BS 5950 or other design codes as indicated in the PSD. 1. 3.1.1 Surface Condition General Condition Steel for fabrication is not to be more heavily pitted or rusted than Grade C of BS 7079 Part A1. 9 Version 1.NPQS C5-10 Structural Steelwork 3.2 Rectification of Surface Defects For hot rolled plates and wide flats.0 .1 MATERIALS Steel Sections/Elements 3.3. rectify the surface in accordance to BS EN 10163-2 Clause 5 (Repair Procedures).2 Mill Certificates All steel elements are to have the manufacturer’s mill test certificates indicating compliance with the specified codes.1.1 Material Qualities Material qualities. dimensions and tolerances are to comply with the appropriate standard as tabulated below: MATERIAL.3 3. 3.1 - SS 470: Part 1 (BS EN 10210-1) SS 503: Part 1 (BS EN 10219-1) BS 4429 - BS 7668 - SS 470: Part 2 (BS EN 10210-2) SS 503: Part 2 (BS EN 10219-2 (4)) BS EN 10056-2 BS EN 10055 As UB & UC BS EN 10029 BS EN 10051 - 3. 3.1.1.3. DIMENSION AND TOLERANCE STANDARDS Material Qualities Form Non-alloy Fine Q&T Weathering steels grain steels steels steels Universal Beams & Columns Joists Channels Rolled Asymmetric Beams Angles Rolled Tees Split Tees Plates (Reversing Mill) Plates (Cut from Coil) Bars and Rods Wide Flats(3) Hollow Sections (Hot-Finished)(5) Hollow Sections (5) (Cold-Formed) Turnbuckles Dimensions Tolerances BS 4 -1 BS EN 10034 BS EN 10024 BS EN 10279 (4) BS 4 -1 BS 4 -1 (4) BS EN (1) 10025 BS EN 10113 (2) BS EN 10137-2 BS EN 10155 BS EN 10056-1 BS EN 10055 BS 4 . if there are surface imperfections and defects as classified in BS EN 10163-2 Clause 4 (Requirements) revealed during surface preparation. 3 Washers Ordinary steel washers (normal diameter series) are to comply with BS 4320 Section 2. BS 4395-1 for general grade bolts b. Comply with BS 3692 (grade 8) for grade 8. rectify the surface imperfections and defects revealed during surface preparation in accordance to BS EN 10210-1 Clause 6.3. For galvanised or sherardised bolts use class 10 nuts for 8. 3. 8 for 8.6.3 (Welding Consumables and Electrode Requirements).3.8 and 10 for 10. BS 4395-2 for higher grade bolts 10 Version 1.NPQS C5-10 Structural Steelwork For hot rolled sections.2 3.6 bolts.9).3.1 Ordinary Bolt Assemblies Ordinary bolts (full and part threaded length) are to comply with BS 4190 for all grades.0 . rectify the surface in accordance to BS EN 10163-3 Clause 5 (Repair Procedures). nuts and washers are to comply with: a.9 bolts. if there are surface imperfections and defects as classified in BS EN 10163-3 Clause 4 (Requirements) revealed during surface preparation.3 Fasteners 3.2.2 Welding Consumables Welding consumables for metal arc welding are to comply with ANSI/AWS D1. 3. 3.8 bolts.8 (Surface Condition).1 Clause 5. 3.2 Nuts Comply with BS 4190 (grade 4) for grade 4.1 Countersunk Bolt Assemblies Bolts Comply with BS 4933 for grade 4.8 bolts.3.3. 3. Black steel washers are to comply with BS 4320 Section 2.8 bolts and class 12 nuts for 10.3 High Strength Friction Grip Fasteners Bolts. 3.3. Ensure compatibility between welding consumables and parent materials used for the steelwork. Ordinary nuts are to comply with BS 4190 (grade 4 for grade 4.2.2. For hot rolled hollow sections. Comply with BS 4933 (dimensions) and BS EN ISO 898-1 (material) for grade 8.6 (cup headed bolts and 90° countersunk head bolts). 8 bolts.5 3.5.6 Grout Grout is to comply with BS 5950-2 Section 2.5.6 bolts.8 bolts.6 and 8.65√A.8.6 Shear Studs Proprietary headed studs are to have the following properties: a.0 .4 Lock Nuts for Bolt Assemblies Comply with BS 3692 or BS 4190 as appropriate. Comply with BS 4190: Grade 4 for grade 4.2 Sherardised Coatings Comply with BS 4921. Minimum yield strength of 350 N/mm2 b.NPQS C5-10 Structural Steelwork 3.3. 3. Class 10 for galvanised or sherardised grade 8.5.1 Galvanising Materials Comply with BS EN ISO 1461.8. 3. 3.5. Diameter and nominal length as noted on the drawings 3.0 for all paints and other coatings. Minimum ultimate tensile strength of 450 N/mm2 c.3.3.1 unless otherwise agreed.3 Washers Comply with BS 4320 Section 2 (normal diameter series) for bolts grades 4.4 Surface Coatings Refer to Section C5-20.3 Metallic Blast Cleaning Abrasives Comply with BS 7079-E2 for chilled iron grit.3. Comply with BS 7079-RE3 for cast steel grit.5.5.5.2 Holding Down Assemblies Bolts Nuts Comply with BS 7419 for grades 4. 3. 3. 3. 3.1 3.3. clause 3.3.6 and 8.4 Profiled Steel Decking Comply with BS 5950-4 Clause 3. 3. where A = area of test specimen d.5. Grade 8 for grade 8. Elongation of 15% on a gauge length of 5. 11 Version 1.5 Protective Finishes 3. NPQS C5-10 Structural Steelwork Grout around anchor bolts under base plates and between steel plates and concrete surface is to have a minimum compressive strength at 28 days of 40 N/mm2. 12 Version 1. Proprietary grouts are not to contain high alumina cement.0 . Protect steel against corrosion. 4.2.2 Storage and Handling Prepare and comply with proper storage and handling procedures in approved method statement to ensure achievement of the desired quality and to minimise damage to the steelwork. packing. where necessary.1.2. 4. to ensure achievement of the desired quality.1 Traceability All steel elements are to be identified and traceable to the manufacturer’s material/mill test certificates.NPQS C5-10 Structural Steelwork 4. Mark completed components in locations that will not be covered up by other material after erection to avoid confusion. Carry out drying or re-baking.2. 4.2 Marking Mark all pieces so that they can be identified at all stages of fabrication. Ensure individual piece markings are visible when members are stacked. Hard stamping may be used other than where specified in the PSD. 4.1 WORKMANSHIP General 4. 4.3 Fabrication Prepare and comply with proper fabrication procedures to SO’s acceptance. 4.2.4 Storage and Drying of Welding Consumables Store and protect welding consumables that have been removed from the original package so that the welding properties are not affected. 4.3 Handling Plan and carry out bundling.1 Holding Areas Lay steel in separate holding areas and keep clean. Keep clean and do not allow water to accumulate on components. 13 Version 1. handling and transport in a manner designed to prevent permanent distortion to the steelwork and minimise damage to any protective coating. in accordance with the manufacturer’s recommendations.1. Keep areas of steelwork free of all markings where so required on the Drawings.0 . 4.2 Storage Adequately support steel clear of the ground. 3.2.2. Cut and shape steel by sawing.2 Matching Ensure all matching holes are formed such that fasteners can be inserted freely through the assembled members at right angles to the contact faces. 4. nibbling. The thickness of the material is not greater than 30mm.4 (Holing). 4. Drifting to align holes may be used provided it neither enlarges nor distorts the holes.2.3. shearing.3.1 Cutting Comply with BS 5950-2 Clause 3. punch.3 Drilling through Multiple Thickness Tightly clamp the separate parts before drilling and remove any burrs after separating the parts. Flame-cut edges that are free from significant irregularities require no further treatment other than dressing as specified in 4.1.2. 14 Version 1.NPQS C5-10 Structural Steelwork 4. The holes are free of burrs which would prevent solid seating of the parts when tightened.3.4 Punching Full Size Punching of full size holes is permitted when all the following conditions are satisfied: a. plasma or laser cut and thermal or flame cut round holes for fasteners.3.1 4. cropping.2. b. Thermal holing or full size hole punching are not permitted at the areas indicated in the PSD.3. 4. nor greater than the diameter of the hole being punched.0 . Drill. 4.2. In spliced connections when the holes in mating surfaces are punched in the same direction and the splice plates marked to show the assembly faces. The tolerance on distortion of the punched hole does not exceed that specified.5 Punching and Reaming When the conditions in 4.3.3. 4.2 4.1. plasma or laser cutting and thermal or flame cutting.2 Hand Flame Cutting Flame Cut Edges Use only where it is impractical to use machine flame cutting.3. 4.3(Dressing). c.3. d. punching is still permitted provided that the holes are punched at least 2mm less in diameter than the required size and the holes are then reamed to the full diameter after assembly.3. if packed separately.3 (Cutting).4 is not satisfied. Thermal cutting are not permitted at the areas indicated in the PSD.1 Holing Forming Comply with BS 5950-2 Clause 3. hole sizes are to be bolt diameter +2mm. A 90° rolled.4.1(Ordinary Bolt Assemblies) for strength grade combination of bolt/nuts/washers.4 Bolting 4.2 Holding Down Bolts Hole sizes are to be bolt diameter +6mm with sufficient clearance to ensure the bolt can be accommodated through the base plate when adjusted. 4. 4.4. irregularities and protruding edges. where directed.2 Condition of Bolts Bolt assemblies are to be in such condition immediately before installation that the nut turns freely on the bolt.3. visually inspect all welds within the area of curving or straightening.3. 4.4.3.2 4.4.1.3 4.2 Dressing of Sharp Edges Dress all sharp edges. 4. 15 Version 1.NPQS C5-10 Structural Steelwork 4. burrs.1 Ordinary Bolted Assemblies Make-up of Bolt Assemblies Refer to Clause 3.4. 4.1 Dressing Removal of Burrs Dress cut edges or holes to remove dross.2. If holes are drilled through components that are clamped together not intended to be separated after drilling.4.1 Hole Sizes for Bolting Ordinary and HSFG Bolts a. removal of burrs is not required. 4.0 . After the process is complete.1 4.3.3.3mm.3. hole sizes are to be bolt diameter +3mm. Carry out non-destructive testing of welds. do not use different bolt grades of the same diameter in the same structure.3. 4.4.3 Fitted Bolts Clearance of bolt in hole is not to exceed 0.2. For bolts ≤ 24mm diameter.2 Heating Inspection Control the temperature carefully and do not let the temperature exceed 650°C.1.3. b.3 Differing Grades of Bolts Unless otherwise agreed by the SO. For bolts > 24mm diameter.1.4.4.2. 4.1 4.3. sheared or machined cut edge requires no further treatment.4 Curving and Straightening Curve or straighten components during fabrication using mechanical means or the local application of heat.4. 4. 0 .5 Washers Use at least one washer placed under the nut or bolt head being rotated in each bolt assembly where the rotation might damage the surface protective treatment on the members being connected.3. Place the hardened washer under the nut or head being turned.4.2.2.1 High Strength Friction Grip Fasteners Make-up of Bolt Assemblies Refer to Clause 3. take the joint apart and insert a pack of the same steel material.2.4.4. Re-tap nuts. 4. 4. if necessary.NPQS C5-10 Structural Steelwork 4.10 Fit-up Using Ordinary Bolt Assemblies Draw connected parts firmly together.4.3.3 4. include the proposed method in the erection details. If not specified on the drawings.4 Bolt Length The length of bolt is to be such that at least one clear thread shows above the nut after tightening.2. 4. Use the torque control method. the part-turn method or direct tension indicators in accordance with the manufacturer’s recommendations for tightening in compliance with BS 4604-1.11 Reaming Reaming may be used where the connection design allows the use of larger diameter holes and bolts in cases where drifting would distort the steelwork. 4.4.7 Galvanised Nuts Check after galvanizing to ensure free running on the bolt. 16 Version 1.2.4.4. 4.4. Use a plate or heavy duty washer under the head and nut where the members being connected have oversize or slotted holes. Secure nuts used in connections subject to vibration or reversal of stresses to prevent loosening.2.6 Taper Washers Place under bolt heads and nuts bearing on surfaces sloping 3° or more from a plane at right angles to the bolt axis.4.4.4.8 4.3.2. which may affect the integrity of the joint.3. to ensure satisfactory tightening. 4.3(High Strength Friction Grip Fasteners) for strength grade combination of bolt/nuts/washers. 4. and at least one thread plus the thread run out is clear between the nut and the unthreaded shank of the bolt. 4.3 Calibration of Torque Equipment Calibrate torque devices at least once each shift. If there is a remaining gap more than 2mm.2. 4.9 Tightening Locking of Nuts Use power tools or by hand using appropriate spanners to BS 2583.2 Tightening Use high strength friction grip bolts in compliance with BS 4604-1 or 2.4. short circuiting transfer (GMAW-S) are to conform to all of the requirements of ANSI/AWS D1. short circuiting transfer and flux cored arc welding (FCAW) which conform to all of the requirements of ANSI/AWS D1. deformities or contaminants.5. gas metal arc welding (GMAW) except GMAW-S.5 Holes in Hollow Sections Seal bolt holes and vent holes in hollow sections to prevent the ingress of moisture. Demonstrate by calculation that the connection is adequate for the specified forces. 4.0 . If there is a remaining gap.3.3. 4. which may reduce the slip factor below the design value. If not specified on the design drawings.4. take the joint apart and insert a pack of the same steel material before continuing tightening.1 Section 3 are deemed as pre-qualified and accepted for use without performing the Welding Procedure Specifications (WPS) Qualification Tests.2 Welding Supervisor Carry out welding under the direction of a welding supervisor with appropriate qualifications. discard the complete bolt assembly and do not re-use in the Works.1 Welding Processes Processes for Shielded metal arc welding (SMAW).4. 4. Gas tungsten arc welding (GTAW).1 Section 4. 4. 4.5 Fit-up Using High Strength Friction Grip Fasteners Draw connected parts firmly together with all bolts partially tightened.4. 4.6 Reaming Reaming may be used where the connection design allows the use of larger bolts in cases where drifting would distort the steelwork. a bolt or nut is slackened off for any reason.4. show the proposed method on the shop drawings. Ensure the faying surfaces of friction grip joints are free of distortion.NPQS C5-10 Structural Steelwork Recalibrate where necessary in accordance with BS 4604.3. 17 Version 1. electro-slag welding (ESW) or electro-gas welding (EGW) and gas metal arc welding .5 Welding 4.4.4.7 Faying Surfaces for HSFG Fasteners Remove all mill-scale from the faying surfaces of friction grip joints. 4.5.3. 4.4 Discarded Bolt Assemblies If after tightening.4 Slotted Holes Bolts Where slotted holes are provided for movement connections ensure the joint is free to move. submerged arc welding (SAW). 1 Section 4 Part B for acceptance by the Independent Inspection and Testing Agency. Temporary Welds and Tack Welds 4.5. the SO and the Independent Inspection and Testing Agency prior to the commencement of the works. 18 Version 1. Remove the temporary welds unless otherwise agreed by the SO.1 Clause 3.12 (Partial Joint Penetration Requirements) for Partial Penetration Butt Welding. ANSI/AWS D1. Discontinuities. Make flush the surface with the original surface after the removal.4 Inspection and test plans Submit all inspection and test plans for SO’s acceptance prior to carrying out welding works.11 (Common Requirements of Partial and Complete Joint Penetration Groove Welds) and Clause 3.13 (Complete Joint Penetration Requirements) for Partial Penetration Butt Welding.3 4.3 Availability of Welding Procedure Specifications Make WPS available to the welder. with the following exceptions: a. Remove tack welds. which are not incorporated into the final weld.3. are to be made with electrodes meeting the requirements of the final welds and are to be cleaned thoroughly.9 (Fillet Weld Requirement) for Fillet Welding b.0 .5.1 Clause 3.4. Tack welds are subject to the same quality requirements as the final welds.5.3.5. c. c. unfilled craters and porosity need not be removed before the final submerged arc welding. Preheat is not mandatory for single-pass tack welds which are re-melted and incorporated into continuous submerged arc welds.11 (Common Requirements of Partial and Complete Joint Penetration Groove Welds and Clause 3.3. 4. b. such as undercut. unless otherwise agreed by the SO.1 Welding Procedures Specifications Preparation Prepare Written Welding Procedure Specification (WPS) in accordance with ANSI/AWS D1. which are incorporated into the final weld.1 Assembly Fit-up Fit up joints to the dimensional accuracy in accordance with the following: a. 4. ANSI/AWS D1. 4.NPQS C5-10 Structural Steelwork 4. 4. ANSI/AWS D1.1 Clause 3.2 Procedure Tests All procedure tests conducted are to be witnessed by the Independent Inspection and Testing Agency.5.4 4.4. Tack welds. Multiple-pass tack welds are to have cascaded ends.2 Temporary welds are subject to the same welding procedure requirements as the final welds.5.3.5.5. 0 .5.4.3 Visual Inspection Visually inspect all studs.4 (NonDestructive Testing of Welds).5.4 Bend Test Subject studs to bend tests at locations agreed with the SO. procedures and equipment. 4.5. check by magnetic particle testing method inspection using the acceptance criteria stipulated in Clause 5. 4.5. Grind flush and inspect the area visually. Test a minimum of ten studs in the trial.4 Temporary Attachments Welding of temporary attachments required for fabrication or erection is to be carried out in accordance with the requirements for permanent welds. Remove after use where required by flame cutting or gouging at a point not less than 3mm from the surface of the parent metal.5. carry out welding procedure trial of studs to demonstrate the suitability of the proposed welding system and equipment before commencement of the work. Bend the head of the stud by striking the head of the stud to an angle of approximately 30° from their original axis with a hammer.3 above. 19 Version 1. 4. at the commencement of each shift. The trial is to use the materials and procedures proposed for the works.1 Shear Stud Welding Method Fix shear studs in accordance with the manufacturer’s recommendations for materials.5.5.5.5. During the work.5 Defective Studs Replace any studs with defective welding and re-test as above. 4.5 4.3 Control of Distortion and Shrinkage Procedure and sequence of welding is to be in accordance with ANSI/AWS D1.5.2 Welding Procedure Trial Where required.5. Where the parent metal is more than 20mm thick.1 Clause 5. Test at least 5% of studs and not less than two per beam.NPQS C5-10 Structural Steelwork 4.4. They are to exhibit full 360 degree ‘flash’ with no evidence of undercut into the stud base. 4. each welder is to undertake a minimum of two trial welds.5. 4.5.5. Do not straighten any studs so tested. Do not remove temporary attachments by hammering.5.21 to minimise distortion and shrinkage. Where defective studs are removed check the surface as specified in 4. Under this test the weld is to show no visible signs of cracking or lack of fusion. 6.1(Material Qualities) PD = D/300.0 .2 PDs in Rolled Components After Fabrication Cross Section After Fabrication Squareness of Ends not Prepared for Bearing In accordance with the appropriate standards given in clause 3. L = L/1000 or 3mm whichever is the greater 4. where D is the depth of the section and the deviation is measured relative to the longitudinal axis of the member.6 Removal of Slag Remove slag by light hammering.6. where D is the depth of the section.1 4. 20 Version 1.1.NPQS C5-10 Structural Steelwork 4.1. D = D/300 Plan or Elevation of End 4. where L is the length of the member.6.6. where L is the distance between restraints.3 Squareness of Ends Prepared for Bearing PD = D/1000. 4.1.6 Permitted Deviations (PDs) of Fabrication 4.1. = D/1000 90° D Plan or Elevation 4.4 Straightness PD of a member from a straight line drawn between adjacent points of subsequent effective lateral restraint = 3mm or L/1000.5 Camber PD from specified or proposed camber at mid-length = 6mm or L/1000. whichever is greater.5.6.1 4.1.1. whichever is greater. wire brushing or other means that do not deform the surface of the weld.6. where D is the nominal hole diameter.6. = 3mm 4.6.6 Length PD after cutting. whichever is greater.1 PDs of Fabricated Components Position of Fittings PD from the intended position for fittings and components whose location is critical to the force path = 3mm.6.2.2. measured on the centre line of the section or on the corner of angles = 2mm.6. = 2mm 4.2 Position of Holes PD from the intended position of hole or group of holes = 2mm.0 .2 4. 21 Version 1.2.6.1.3 Punched Holes Distortion caused by a punched hole is not to exceed D/10 or 1mm.NPQS C5-10 Structural Steelwork Deviation L Deviation = L/1000 or 6mm whichever is the greater 4. L± = 2mm 4. 2. PD = ±5mm.6.1 PDs in Plate Girder Sections Depth PD measured on centre line = ± 4mm.75mm 4.6. =0. 22 Version 1.25mm over 50% of the length of contact of the section.6.6. t = t/10 4.6.75mm and are to be less than 0.3.NPQS C5-10 Structural Steelwork D = D/10 or 1mm whichever is the greater 4.2 Flange Width For flange width B < 300mm. For flange width B≥ 300mm.5 Flatness Gaps in joints that depend on contact bearing when assembled during fabrication are not to exceed 0.3.3 4.2. D± = 4mm 4.0 . PD = ±3mm.4 Sheared or Cropped Edges of Plates or Angles Deviation from a 90° edge is not to exceed t/10 where t = plate thickness. 3.6.3. PD on out of flatness = B/100 or 3mm. whichever is greater.0 .6 Top Flange of Crane Girder PD on out of flatness where rail seats = 1mm. PD on out of squareness = B/100 or 3mm. B Flange width = B / 100 or 3mm whichever is the greater 4. 23 Version 1.NPQS C5-10 Structural Steelwork Bw ± B w or B n < 300 = 3mm _ B w or B n > 300 Bn ± = 5mm 4. whichever is greater.3 Squareness of Sections For flange width B. b ± = 5mm 4. B Flange width = B/100 or 3mm whichever is the greater 4.6.6.7 Length PD on length on centre line = ± 3mm.3.4 Web Eccentricity PD on intended position of web from one edge of flange = ± 5mm.6.5 Flanges For flange width B.3. w = Rail width + 20mm w w = 1mm 4.6.3. whichever is greater.6.10 Web Distortion PD on distortion on web depth (or gauge length) = d/150 or 3mm.3. Deviation L Deviation = L/1000 or 6mm whichever is the greater 4. L = L/1000 or 3mm whichever is the greater 4. whichever is greater. where d is depth of stiffener.3.6. where L is length.9 Curve or Camber PD on intended curve or camber at mid-length of curved portion = L/1000 or 6mm.6.12 Web Stiffeners PD on straightness of stiffener out of plane with web after welding = d/500 or 3mm. where L is length and deviation is measured with web horizontal. where d is depth of web.6.3. whichever is greater.11 Cross Section at Bearings PD on squareness of flanges to web = D/300 or 3mm. gauge length = web depth d = d/150 or 3mm whichever is the greater 4. whichever is greater.6.3. D = D/300 or 3mm whichever is the greater 4. 24 Version 1. whichever is greater.NPQS C5-10 Structural Steelwork L± = 3mm 4.0 .3. where D is depth of section.8 Flange Straightness PD on straightness of individual flanges = L/1000 or 3mm. 6. whichever is greater.1 PDs in Box Sections Plate Widths For Bf or Bw < 300mm.NPQS C5-10 Structural Steelwork d = d/500 or 3mm whichever is the greater PD on straightness of stiffener in plane with web after welding = d/250 or 3mm. d = d/250 or 3mm whichever is the greater 4.6.4. where D is section depth.3 Plate Distortion PD on distortion on width or gauge length = w/150 or 3mm. whichever is the greater. where Bf . where w is depth of web. 25 Version 1.4 4.6.0 . PD = ±3mm. For Bf or Bw ≥ 300mm.6. PD = ± 5mm. where d is depth of stiffener.4. Bw are flange width and web depth respectively.4. = D/300 D 4. B ± f B ± w B or B w < 300 f = 3mm _ B or B w > 300 f = 5mm 4.2 Squareness PD on squareness measured at diaphragm positions = D/300. NPQS C5-10 Structural Steelwork gauge length = width.6 Length PD on length measured on centre line = ± 3mm. L± = 3mm 26 Version 1. where L is full length. L = L / 1000 or 3mm whichever is the greater 4.4. w w = w/150 or 3mm whichever is the greater 4. d = d / 500 or 3mm whichever is the greater PD on straightness out of plane to plate after welding = d/250 or 3mm. d = d / 250 or 3mm whichever is the greater 4.6.5 Web Stiffeners PD on straightness in plane with plate after welding = d/500 or 3mm.0 . where d is depth of web.4. whichever is the greater.6. where d is depth of web. whichever is the greater. whichever is the greater.6.4.4 Web or Flange Straightness PD on straightness of individual web or flanges = L/1000 or 3mm. 7.6.4 Alignment Align each part of the structure as soon as practicable after erection.7 Erection 4. whichever is the greater.4.1 General Prepare and comply with proper erection procedures to SO’s acceptance. plumbed and temporarily connected so that members will not be displaced during subsequent erection or alignment of the remainder of the structure.NPQS C5-10 Structural Steelwork 4.7 Curve or Camber PD on deviation from intended curve or camber at mid-length of curved portion when measured with the un-cambered side horizontal = L/1000 or 6mm. 4.2 Erection Loads Ensure that the structure is not overloaded by stacking of materials.5(Welding) above. 4. and for dimensional checks carried out subsequently.0 . paying attention to site conditions.7.7. Deviation L Deviation = L / 1000 or 6mm whichever is the greater 4. where L is length of the curved portion. to ensure achievement of the desired quality and safety.3 Temporary Supports Any temporary supports used may be removed after the structure has been lined. 27 Version 1. levelled and plumbed. 4. Do not carry out site welding in inclement weather unless adequate weather protection is provided for welders and materials. constraints and restrictions. Carry out all site welding in accordance with clause 4. 4.6 Site Welding Carry out site welding only by agreement with the SO or as shown on the design drawings. 4.5 Temperature Adjustment Take due account of the effects of temperature on the structure and measuring equipment when measurements are made for setting-out and erection. provided sufficient components have been erected and secured to ensure the overall structure remains stable under the worst anticipated conditions of loading. Adopt 30°C as the reference temperature unless otherwise agreed. Do not make permanent connections between members until the structure has been sufficiently aligned. levelled.7.7.7. 8.8. Inspect for position and level in good time before the planned start of steelwork erection.7. In the event of any discrepancies found. mix and place proprietary grout in accordance with the manufacturer’s recommendations. Where components and fixings are cast in by others ensure that they are also within the anticipated PDs before commencing steel erection.8 Packs and Wedges Plumb and level columns using steel packs and wedges of adequate strength and stiffness. 4.1 Receiving Structures and Connections Ensure that structures by others to which the steelwork attaches is constructed within the anticipated PDs before commencing steel erection.NPQS C5-10 Structural Steelwork 4. 4. temporary supports. levelled. Use templates to set in the holding-down bolts. clean the space under the column base plates to be free of all extraneous matter.10 Profiled Steel Decking Install in accordance with manufacturer’s recommendations. Prepare.9 Grouting Carry out grouting in accordance with BS 5950-2 Clause 6. Immediately before grouting.7 Foundation Bolts Hold foundation bolts firmly in position during all setting-in operations. Where packings are to be left in position and subsequently grouted. and not larger than necessary for the purpose. 4. Bolt level: 28 Version 1. threads and nuts against damage. etc. a.3. place them such that they are totally enclosed by the grout. lapping. including the provision of edge trims.1 PDs of Holding Down Bolts Bolts or Bolt Groups with Allowance for Adjustment +25/-5mm.8 Permitted Deviations (PDs) in Erection Erect steelwork within the PDs in the following clauses. corrosion and contamination at all stages of construction.7. 4.2 4.7. propose and correct the discrepancies. Keep pockets formed around foundation bolts clean and free from all extraneous matter. Do not carry out grouting under column base plates until a sufficient portion of the structure has been aligned. 4.0 .7.8.2. notify the SO. 4. Protect bolts. plumbed and adequately braced. 4.2.5 mm bolt level = ± 3 mm position in plan and elevation 4. a.8. End of bolt: b.1 PDs of Erected Components Position of Columns at Base PD of section centreline from the specified position = 10mm.8. = 10mm 29 Version 1. Bolt level: b.8.8. = ± 10 mm from specified position at top of concrete = + 25 mm . a. ±3mm from specified position at top of concrete. Bolt centroid: 25mm at top of concrete ±10mm from specified position at top of concrete. Bolt centroid: = + 45 mm . 4. Minimum clearance: c.4 4.5 mm bolt level 4. Bolt centroid: = ± 3 mm from specified position at top of concrete = + 45 mm . ±3mm position in plan and elevation.2.3 PD of Level of Base Plate PD of level of column base plate = 5mm.0 .3 Bolts or Bolt Groups Cast into Walls (No Allowance for Adjustment) +45/-5mm.5 mm bolt level 25 mm minimum clearance at top of concrete 4.8.2 Bolts or Bolt Groups with No Allowance for Adjustment +45/-5mm.NPQS C5-10 Structural Steelwork b. H h = storey height h h = ± h/600 or 5 mm whichever is greater H = 50mm maximum 4. where h is the storey height.6 Gap Between Bearing Surfaces PD = (D/1000 +1) mm where D is the dimension along the bearing surface. where L is the specified overall dimension in metres. PD of column at top storey relative to specified position at base plate = 50mm maximum.5 Alignment of Adjacent Perimeter Columns PD of one column relative to the next on a line parallel to the grid line = 10mm when measured at the base or splice level. on main axes. 4.8.4. whichever is greater.8.8.8.4.4.NPQS C5-10 Structural Steelwork 4. where h is the storey height.0 . 30 Version 1. excluding portal frame columns. whichever is greater.4.4.8.3 Plumb of Single Storey Columns PD of top relative to base = ± h/600 or 5mm. H H = ± H/600 or 5 mm whichever is greater Max = ± 25mm 4.4 Plumb in Multi Storey Columns PD in each storey of column = h/600 or 5mm. critical face of columns = 10 mm 4.2 Overall Plan Dimension PD on length or width = 20mm for L < 30m and [20 + 0.25 (L-30)] mm for L ≥ 30m. PD of two or more beams meeting at a column = ± 5mm. = ± 5mm c.0 .4. Floor Level h Floor Level h<3m. PD on level of adjacent beams within a distance of 5m = ± 5mm.NPQS C5-10 Structural Steelwork D = (D / 1000) + 1 mm D 4. = ± 5mm d. h<3m. = 5mm = h/600 e.7 Level of Beams a. PD of beam relative to adjacent beam above or below = 5mm for h < 3m and h/600 for h ≥ 3m. 31 Version 1. PD on level of beam at its ends = 5mm. Specified Level = ± 10mm b.8. PD from specified level of beam at supporting column = ± 10mm. where h = storey height in m. 5mm.8. x± Actual beam C L Grid line Generic profile deck may span either direction = ± 10mm 32 Version 1.4.4.10 Joints in Gantry Crane Rails a. PD on rail surface across joint = 0. = 0.8.NPQS C5-10 Structural Steelwork 4.0 .4.5mm b.4. PD on rail edge alignment across joint = 1mm. = 1mm 4.9 Crane Gantries Gauge of Rail Tracks PD from true gauge = ± 10mm. H c = ± Hc /1000 or 5mm whichever is greater Max = ± 25mm 4. whichever is greater to a maximum of ± 25mm.8 Plumb of Crane Gantry Columns PD = ± Hc/1000 or 5mm.11 Profile Steel Floor Decking PD of dimension between deck edge trim and perimeter beam = ± 10mm for deck span in either direction. G+H = ± 10mm 4.8.8. Propose and carry out remedial measures as required.8. 33 Version 1.5 Deviations Exceeding PDs Inform the SO as soon as possible if checks show that the deviation in position of the steelwork as erected exceeds the PDs given above.0 .NPQS C5-10 Structural Steelwork 4. i.1. Number of pieces of steel sections b. Tolerances d. Fabrication procedure/manual. j.4. Detailed drawings and calculations for temporary works. 34 Version 1. k. f. Safety procedures for handling and erection of steelwork on site. All other fabrication and erection details 5. site constraints. Sequence and method of erection and assembly of structural members taking into account the site conditions. where partial or complete fabrication work is required on site. list of subcontractors/suppliers and their scope of works. storage area. etc. A site plan showing the work layout area. g. datum level. Include at least the following information: a. site restriction and interface with other trades. c. locations (local and/or overseas). submit to the SO for acceptance calculations and drawings for the connection details within time as directed by the SO prior to commencement of the Works. platforms and weather protection where site welding is to take place. Assembly of structural members on the ground level before erection. Maximum size of structural steel components that can be delivered to the site. d.1. storage.1.1.1 VERIFICATION AND SUBMISSIONS Submission 5. access routes.1 Design Submission When required in Clause 1. 5. Remedial procedures for damaged steelwork during fabrication. Connection details e.0 . h. Include all details of the steel structures incorporating at least the following information: a. Bearing locations and details f.3 Method Statement Provide a detailed method statement to the SO for acceptance within directed time prior to commencement of any works. b.2 Shop Drawings Submit to the SO for acceptance complete and coordinated shop drawings within time as directed by the SO prior to commencement of any works. e.NPQS C5-10 Structural Steelwork 5. position and type of cranes. Storage and handling. transportation. Details of staging. etc. quality assurance system. Details of proposed site inspection systems by the Accredited Inspection Body. handling and erection. Dimensions c. setting-out lines. 5. material certificates duly verified by the Independent Inspection and Testing Agency within time as directed by the SO prior to commencement of any work.7 Inspection by ITA Submit all reports from the Independent Inspection and Testing Agency to SO periodically as agreed with the SO.6. b. Fabrication d.2 Test Certificates/Reports for Bolts and Inserts Provide test certificates/reports and demonstrate by testing on 2% of actual materials used that bolts and inserts used in the Works conform to the specified requirements. including tack and sealing welds. Welder qualification records. stud welding procedure records.NPQS C5-10 Structural Steelwork 5. Preparation and submission of construction information b. 5. 5. Erection Include in the programme. Application of protective coatings e.1.8 As-built Drawings Submit as-built drawings to the SO for record upon completion of the Works. Transportation to site f. Details of welding procedures in accordance with ANSI/AWS D1.1.1.1. c.0 . 5. Details of proposed shop inspection system by the Independent Inspection and Testing Agency. 5.1. and trial assemblies.1. welding procedure records.6.5 Programme Provide a detailed programme to show the planned timing of the various items of work to be done within time as directed by the SO. Include information on all element type. including: a. 5. Order and delivery of materials c. inspection and testing.1.6 Material Certificates Submit to the SO for acceptance.1 Mill Certificates Provide mill certificates for every batch of supply confirming compliance with the specified standards before the supply of material to the works. the time required for all procedural trials. 5.4 Construction Information Provide the following information within time as directed by the SO prior to commencement of the Works: a. position including deviation exceeding the 35 Version 1. sizes.1 for all welds. verifying that the fabrication and erection of the works comply with the specified requirements.4 Non-Destructive Testing of Welds 5. Keep records of all tests and make them available to the SO and the Independent Inspection and Testing Agency for examination throughout the duration of the Works. Calibration and testing of equipment f. 5. Inspection requirements may be reduced by agreement with the SO based on satisfactory performance in the initial tests.1 Inspection of Accuracy of Fabrication and Erection Provide inspection reports in agreed batches endorsed by the Independent Inspection and Testing Agency. 5.1 Scope of Inspection Carry out Non-Destructive Testing as tabulated below unless otherwise agreed. Immediately examine any welds that will be covered up before loss of access. connection and assembly details.2 Procedural Trial and Trial Assemblies Carry out procedural trial and trial assemblies as agreed with the SO. The acceptance criteria for visual inspection are to be in accordance with ANSI/AWS D1.3. Organisation charts and responsibilities c. Testing and inspection procedures Subcontractors and suppliers 5.1 Table 6.NPQS C5-10 Structural Steelwork permitted PD if any. including tests on material and workmanship in accordance with the Specification. The Quality Manual is to include at least information on the following: a. Quality policy b.4.1. 5. prior to commencement of the Works. and protective works applied if any.3.1.2 Visual Inspection of Welds Carry out visual inspection over the full lengths of all welds prior to any NonDestructive Testing (NDT).3 Inspection 5.0 . Give adequate period of notice as agreed with the SO. Facilities and equipment e. Internal quality control and audits d. Full Penetration Butt Welds Partial Penetration Butt Welds 36 Version 1.9 Quality Control Manual Submit a Quality Manual containing a QA/QC programme for the Works to the SO for acceptance within directed time frame. 5. 1(Scope of Inspection). the procedure and technique are to be in accordance with ASTM E709. carry out NDT not less than 48 hours after the completion of the welds.4.1(Scope of Inspection). 5.3 Magnetic Particle Testing (MT) and Penetrant Testing (PT) Where magnetic particle testing (MT) is required in accordance with Clause 5.NPQS C5-10 Structural Steelwork Examples: Examples: MT / PT Thickness Frequency Thickness Frequency All thicknesses 50% (site welds 100%) tmax ≥ 3 mm 50% (site welds 100%) Fillet Welds All thicknesses 50% (site welds 100%) tmax ≥ 3 mm 50% (site welds 100%) UT / RT Examples: MT / PT Thickness Frequency Thickness Frequency Fillet weld size ≥ 3 mm 10% (site welds 100% but longitudinal welds 0. carry out the testing at least 24 hours after the completion of the welds.4.2 Hold Time Prior to NDT For welds subject to NDT.0 . use Penetrant testing in accordance with the procedure and technique given in ASTM E165. For quenched and tempered steel. If Magnetic Particle testing is impractical.4.4.5m in each 10m or part thereof) Fillet weld size ≥ 20 mm 20% (site welds 100% but longitudinal welds 1.1 Section 6 Part F. 5.0m in each 10m or part thereof) UT / RT As directed by SO 5. the procedure and technique are to be made in accordance with ANSI/AWS D1.4 Ultrasonic Examination (UT) Where ultrasonic testing is required in accordance with Clause 5.4. 37 Version 1. 4.1 Section 6 Part E.4. for example when the plate thickness is less than 8mm.0 .4.1 Section 6 Part C.6 Acceptance Criteria and Corrective Actions Acceptance criteria are to be in accordance with ANSI/AWS D1. use radiographic testing in accordance with the procedure and technique given in ANSI/AWS D1. 5. 5.NPQS C5-10 Structural Steelwork If ultrasonic testing is impractical. the procedure and technique are to be in accordance with ASTM E94 and ASTM E747.7 Weld Test Records Record the results of all visual inspections and non-destructive testing and make all records available for inspection. Propose corrective actions to the SO for acceptance if the welds do not conform to the acceptance criteria. 5.5 Radiographic Examination (RT) Where radiographic testing is required in accordance with Clause 5. 38 Version 1.1(Scope of Inspection).4.