View
684
Download
59
Category
Preview:
DESCRIPTION
This section covers requirements for the fabrication and erection of normal structural steelwork in buildings. It does not cover the use of stainless stell in special structures
Citation preview
NPQSC5-10 Structural Steelwork
Version 1.0
National Productivity and Quality Specifications (NPQS)
C5-10 Structural Steelwork
NPQSC5-10 Structural Steelwork
Version 1.0
CONTENTS
Page
1. GENERAL 11.1 Scope 11.2 Related Sections 11.3 Standards and Technical Reference 11.4 Trade Preambles 31.5 Definitions 6
2. PERFORMANCE REQUIREMENTS 72.1 Design Brief 72.2 Loading During Construction 7
3. MATERIALS 83.1 Steel Sections/Elements 83.2 Welding Consumables 93.3 Fasteners 93.4 Profiled Steel Decking 103.5 Protective Finishes 103.6 Grout 10
4. WORKMANSHIP 124.1 General 124.2 Storage and Handling 124.3 Fabrication 124.4 Bolting 144.5 Welding 164.6 Permitted Deviations (PDs) of Fabrication 194.7 Erection 264.8 Permitted Deviations (PDs) in Erection 27
5. VERIFICATION AND SUBMISSIONS 325.1 Submission 325.2 Procedural Trial and Trial Assemblies 345.3 Inspection 345.4 Non-Destructive Testing of Welds 34
NPQSC5-10 Structural Steelwork
Version 1.0Page 1
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 normalstructural steelwork in buildings. It does not cover the use of stainless steel in specialstructures.
This document specifies project specific data to be read in conjunction with sectionC5-10 of NPQS. All modification and additions noted in this document takeprecedence over clauses noted in NPQS. Clause references in this document tie withthose in C5-10 with the same clause title.
1.2 Related Sections
Read this work section in conjunction with the relevant requirements of the other worksections 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 relevantrequirements of the Standards and Codes listed below or referenced in the body ofthe Specification. Alternative Standards and Codes may be proposed for approval bythe SO, provided it can be demonstrated that the alternative Standards and Codescomply with the requirements of the standards specified. All Standards and Codesquoted 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 structuralsteels
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/AWSD1.1-02
Structural welding code. Steel
ASTM E165 Standard test method for liquid penetrant examination
ASTM E709 Standard guide for magnetic particle examination
ASTM E747 Controlling quality of radiographic testing using wire penetrameters
BS EN ISO 898-1
Mechanical properties of fasteners made of carbon steel and alloy steel.Bolts, screws and studs
BS EN ISO 1461 Hot dip galvanised coatings on fabricated iron and steel articles.Specifications and test methods
NPQSC5-10 Structural Steelwork
Version 1.0Page 2
BS EN 10024 Hot rolled taper flange I sections. Tolerances on shape and dimensions
BS EN 10025 Hot rolled products of non-alloy structural steels. Technical deliveryconditions
BS EN 10029 Tolerances on dimensions, shape and mass for hot rolled steel plates3mm thick or above
BS EN 10051 Specification for continuously hot-rolled uncoated plate, sheet and strip ofnon-alloy and alloy steels. Tolerances on dimensions and shape
BS EN 10113 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 thequenched 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 Structural steels with improved atmospheric corrosion resistance.Technical delivery conditions
BS EN 10163 Specification for delivery requirement for surface condition of hot rolledsteel plates, 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 structuralsteels
Part 1: Technical delivery requirements
Part 2: Tolerances, dimensions and sectional properties
BS EN 10219 Cold formed welded structural hollow sections of non-alloy and fine grainsteels
BS EN 10279 Hot rolled steel channels. Tolerances on shape, dimension and mass
BS EN 10034 Structural steel I and H section. Tolerance on shape and dimensions
BS EN 10055 Hot rolled steel equal flange tees with radiused root and toes. Dimensionsand tolerances on shape and dimensions.
BS EN 10056-1 Structural steel equal and unequal leg angles. Dimensions
BS EN 10056-2 Specification for structural steel equal and unequal leg angles. Toleranceson shape and dimensions
BS 4-1 Structural steel sections. Specification for hot rolled sections
BS 2583 Podger spanners
BS 3692: ISO metric precision hexagon bolts, screws and nuts – specification
BS 4190 ISO metric black hexagon bolts, screws and nuts – specification
BS 4320 Metal washers for general engineering purposes
NPQSC5-10 Structural Steelwork
Version 1.0Page 3
BS 4395 High strength friction grip bolts and associated nuts and washers forstructural engineering (metric series)
BS 4429 Specification for rigging screws and turnbuckles for general engineeringlifting purposes and pipe hanger applications
BS 4604 Use of high strength friction grip bolts in structural steelwork (metric series)
BS 4921 Specification for sherardised coatings on iron and steel
BS 4933 ISO metric black cup and countersunk head bolts and screws withhexagon nuts
BS 5531 Code of practice for safety in erecting structural frames
BS 5950 Structural use of steelwork in building
Part 1: Code of practice for design. Rolled and welded sections
Part 2: Specification for materials, fabrication and erection. Rolled andwelded 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 relatedproducts.
Part A1: Visual assessment of surface cleanliness
BS 7419 Specification for holding down bolts
BS 7644 Direct tension indicators.
Part 1: Specification for compressible washers
Part 2: Specification for nut face and bolt face washers
BS 7668 Weldable structural steels. Hot finished structural hollow sections inweather resistant steels
In the event that the Standards or Codes are partially superseded or becomeobsolete, refer to the latest edition or the approved substitution for the relevantclauses.
1.3.2 Technical Reference
When carrying out the works, take guidance from the following technical reference:
a. UK’s National Structural Steelwork Specification (NSSS), 4th Edition, 2002.
1.4 Trade Preambles
1.4.1 Contractor’s Submissions and Proposals
1.4.1.1 Connection Design
Develop the connection design when required as indicated in the PSD.
Development of the design of connections is *required / not required.
Engage a PE (civil) to develop the design of the connections based on the structuraldesign drawings.
1.4.1.2 Temporary Works
Engage a PE to plan, design and supervise any necessary temporary supports toensure the structural steelwork is stable throughout the construction, paying attentionto the safe erection of structural steelwork in accordance with BS 5531.
NPQSC5-10 Structural Steelwork
Version 1.0Page 4
1.4.2 Shop Drawings
Engage qualified and experienced personnel to prepare coordinated shop drawingsfor the fabrication and erection of the steelwork.
1.4.3 Qualifications
1.4.3.1 Steel Fabricators
Engage steel fabricators who are accredited under the Structural Steel FabricatorsAccreditation Scheme of the Singapore Structural Steel Society for the fabricationworks.
Refer to the PSD for the required grade of the fabricator.
The required grade of steel fabricator is ____.
1.4.3.2 Supervisors
All structural steelwork and associated works are to be undertaken and supervised byappropriately experienced personnel. Provide evidence of personnel’s pastexperience and certificate to the SO for acceptance prior to commencement of theWorks.
1.4.3.3 Welder Qualification
Submit evidence of welders’ competence to the to undertake the specified work.
The welders are to be tested to meet the requirements of ANSI/AWS D1.1 Section 4Part C. The welder’s test is to be conducted and certificates are to be issued by theIndependent Inspection and Testing Agency.
1.4.4 Quality Control Plan
Submit and work to a quality control plan as agreed with the SO. Refer to the GeneralRequirements section, clause 1.4.10 for guidance.
1.4.5 Accredited Laboratory
Engage a laboratory accepted by the SO and accredited under the SingaporeLaboratory Accreditation Scheme (SINGLAS) to carry out tests and checks asrequired by this Specification, including all on site weld tests where applicable.
1.4.6 Independent Inspection and Testing Agency (ITA)
Appoint an independent Inspection and Testing Agency (ITA) when required asindicated in the PSD.
Appointment of an accredited inspection body is *required / not required.
When required, the scope of service of the ITA shall be as follows:
S/N Description Tick whereapplicable
1. Review the quality manuals, inspection & test plans
2. Review fabrication and erection procedures
3. Review of welding procedure specification, procedurequalification records, welder and welding operator qualificationrecords.
4. Pre-inspection meeting and audit of fabricator facilities/plants
NPQSC5-10 Structural Steelwork
Version 1.0Page 5
5. Review of material test certificates/records, verify or inspectmaterials and witness pre-treatment processes, if any
6. Witness cutting/edge joint preparations, verify joint geometryand inspect fit-up condition
7. Verify that welding processes are carried out in accordancewith the approved welding procedures, codes/standards andrelevant documents
8. Perform visual inspection and verify dimensional records
9. Select weld joints for testing & witness non-destructive testingand assess all results
10. Witness blasting & galvanising processes
11. Inspect painting and galvanising works
12. Identify & verify completed structural members and witness thehandling of these members onto lorry/truck for delivery to site
13. Inspect delivered structural members for damage due tohandling and transportation
14. Inspect the assembly of structural members at erection siteprior to welding
15. Verify all welding procedure and welder qualification records atsite
16. Witness procedure trial of stud welding process
17. Inspect all welds & bolt tightening
18. Select weld for testing and witness site NDT
19 Inspect all remaining site painting and witness repairing of allprotective treatment works
20. Witness fireproofing mock-up test as well as laboratory tests
21. Witness and inspect the application of fireproofing works
22. Final inspection of all structural members
23. Review all documents and records including but not limited tothe following:
- Dimensional
- Procedures
- Testing
Alternatively, the SO may engage the ITA separately.
In either of the above cases, make available to the ITA the following:
a. All requested documentation and a detailed programme to allow the ITA todischarge its duties and to witness significant stages in the fabrication anderection process.
b. Any instruments or other equipment required checking the accuracy and qualityof the works.
NPQSC5-10 Structural Steelwork
Version 1.0Page 6
1.5 Definitions
a. DesignDrawings
Drawings showing the dimensioned layout of the steelstructure with the size and material grades of all members,the forces to be developed in their connections and anycambers etc, from which shop drawings are made.
b. ShopDrawings
Drawings showing all necessary information to fabricate thestructural steelwork, including the piece markings with thelocation in the structure.
c. Reaming Forming, shaping, tapering, or enlarging a hole with a reamer.
d. FayingSurfaces
Surfaces which are tightly or closely fitted.
NPQSC5-10 Structural Steelwork
Version 1.0Page 7
2. PERFORMANCE REQUIREMENTS
2.1 Design Brief
When carrying out design as described in Clause 1.4.1, ensure the design conformsto the requirements of BS 5950 or other design codes as indicated in the PSD.Design the connections based on forces given in the design drawings.
When carrying out design as described in Clause 1.4.1, ensure the design conformsto the requirements of ____.
2.2 Loading During Construction
Ensure that the steelwork is adequately braced or restrained to withstand all loadingsliable to be encountered during construction without inducing excessive stresses,deflections or distortion in the structure.
NPQSC5-10 Structural Steelwork
Version 1.0Page 8
3. MATERIALS
3.1 Steel Sections/Elements
3.1.1 Material Qualities
Material qualities, dimensions and tolerances are to comply with the appropriatestandard as tabulated below:
MATERIAL, DIMENSION AND TOLERANCE STANDARDSMaterial Qualities
Form Non-alloysteels
Finegrainsteels
Q&Tsteels
Weatheringsteels
Dimensions Tolerances
UniversalBeams &Columns
BS 4 -1 BS EN10034
Joists BS 4 -1 BS EN10024
Channels BS 4 -1 BS EN10279
RolledAsymmetricBeams
(4) (4)
Angles BS EN 10056-1 BS EN10056-2
Rolled Tees BS EN 10055 BS EN10055
Split Tees BS 4 - 1 As UB & UCPlates(Reversing Mill)
- BS EN10029
Plates(Cut from Coil)
- BS EN10051
Bars and Rods - -Wide Flats(3)
BS EN10025 (1)
BS EN10113
BS EN10137-2(2)
BS EN10155
- -Hollow Sections(Hot-Finished)(5)
SS 470: Part 1(BS EN 10210-1)
- BS 7668 SS 470: Part 2(BS EN 10210-2)
Hollow Sections(Cold-Formed)(5)
SS 503: Part 1(BS EN 10219-1)
- - SS 503: Part 2(BS EN 10219-2 (4))
Turnbuckles BS 4429
3.1.2 Mill Certificates
All steel elements are to have the manufacturer’s mill test certificates indicatingcompliance with the specified codes.
3.1.3 Surface Condition
3.1.3.1 General Condition
Steel for fabrication is not to be more heavily pitted or rusted than Grade C of BS7079 Part A1.
3.1.3.2 Rectification of Surface Defects
For hot rolled plates and wide flats, if there are surface imperfections and defects asclassified in BS EN 10163-2 Clause 4 (Requirements) revealed during surfacepreparation, rectify the surface in accordance to BS EN 10163-2 Clause 5 (RepairProcedures).
NPQSC5-10 Structural Steelwork
Version 1.0Page 9
For hot rolled sections, if there are surface imperfections and defects as classified inBS EN 10163-3 Clause 4 (Requirements) revealed during surface preparation, rectifythe surface in accordance to BS EN 10163-3 Clause 5 (Repair Procedures).
For hot rolled hollow sections, rectify the surface imperfections and defects revealedduring surface preparation in accordance to BS EN 10210-1 Clause 6.8 (SurfaceCondition).
3.2 Welding Consumables
Welding consumables for metal arc welding are to comply with ANSI/AWS D1.1Clause 5.3 (Welding Consumables and Electrode Requirements).
Ensure compatibility between welding consumables and parent materials used for thesteelwork.
3.3 Fasteners
3.3.1 Ordinary Bolt Assemblies
Ordinary bolts (full and part threaded length) are to comply with BS 4190 for allgrades.
Ordinary nuts are to comply with BS 4190 (grade 4 for grade 4.6, 8 for 8.8 and 10 for10.9).
For galvanised or sherardised bolts use class 10 nuts for 8.8 bolts and class 12 nutsfor 10.9 bolts.
Black steel washers are to comply with BS 4320 Section 2.
3.3.2 Countersunk Bolt Assemblies
3.3.2.1 Bolts
Comply with BS 4933 for grade 4.6 (cup headed bolts and 90° countersunk headbolts).
Comply with BS 4933 (dimensions) and BS EN ISO 898-1 (material) for grade 8.8bolts.
3.3.2.2 Nuts
Comply with BS 4190 (grade 4) for grade 4.6 bolts.
Comply with BS 3692 (grade 8) for grade 8.8 bolts.
3.3.2.3 Washers
Ordinary steel washers (normal diameter series) are to comply with BS 4320 Section2.
3.3.3 High Strength Friction Grip Fasteners
Bolts, nuts and washers are to comply with:
a. BS 4395-1 for general grade bolts
b. BS 4395-2 for higher grade bolts
NPQSC5-10 Structural Steelwork
Version 1.0Page 10
3.3.4 Lock Nuts for Bolt Assemblies
Comply with BS 3692 or BS 4190 as appropriate.
3.3.5 Holding Down Assemblies
3.3.5.1 Bolts
Comply with BS 7419 for grades 4.6 and 8.8.
3.3.5.2 Nuts
Comply with BS 4190:
Grade 4 for grade 4.6 bolts.
Grade 8 for grade 8.8 bolts.
Class 10 for galvanised or sherardised grade 8.8 bolts.
3.3.5.3 Washers
Comply with BS 4320 Section 2 (normal diameter series) for bolts grades 4.6 and 8.8.
3.3.6 Shear Studs
Proprietary headed studs are to have the following properties:
a. Minimum yield strength of 350 N/mm2
b. Minimum ultimate tensile strength of 450 N/mm2
c. Elongation of 15% on a gauge length of 5.65�A, where A = area of test specimen
d. Diameter and nominal length as noted on the drawings
3.4 Profiled Steel Decking
Comply with BS 5950-4 Clause 3.1 unless otherwise agreed.
3.5 Protective Finishes
3.5.1 Galvanising Materials
Comply with BS EN ISO 1461.
3.5.2 Sherardised Coatings
Comply with BS 4921.
3.5.3 Metallic Blast Cleaning Abrasives
Comply with BS 7079-E2 for chilled iron grit.
Comply with BS 7079-RE3 for cast steel grit.
3.5.4 Surface Coatings
Refer to Section C5-20, clause 3.0 for all paints and other coatings.
3.6 Grout
Grout is to comply with BS 5950-2 Section 2.5.
Grout around anchor bolts under base plates and between steel plates and concretesurface is to have a minimum compressive strength at 28 days of 40 N/mm2.
NPQSC5-10 Structural Steelwork
Version 1.0Page 11
Proprietary grouts are not to contain high alumina cement.
NPQSC5-10 Structural Steelwork
Version 1.0Page 12
4. WORKMANSHIP
4.1 General
4.1.1 Traceability
All steel elements are to be identified and traceable to the manufacturer’smaterial/mill test certificates.
4.1.2 Marking
Mark all pieces so that they can be identified at all stages of fabrication.
Mark completed components in locations that will not be covered up by other materialafter erection to avoid confusion.
Hard stamping may be used other than where specified in the PSD.
Hard stamping may be used other than at the following areas:
a. _____
b. _____
Keep areas of steelwork free of all markings where so required on the Drawings.
4.2 Storage and Handling
Prepare and comply with proper storage and handling procedures in approvedmethod statement to ensure achievement of the desired quality and to minimisedamage to the steelwork.
4.2.1 Holding Areas
Lay steel in separate holding areas and keep clean.
4.2.2 Storage
Adequately support steel clear of the ground. Keep clean and do not allow water toaccumulate on components. Protect steel against corrosion.
Ensure individual piece markings are visible when members are stacked.
4.2.3 Handling
Plan and carry out bundling, packing, handling and transport in a manner designed toprevent permanent distortion to the steelwork and minimise damage to any protectivecoating.
4.2.4 Storage and Drying of Welding Consumables
Store and protect welding consumables that have been removed from the originalpackage so that the welding properties are not affected.
Carry out drying or re-baking, where necessary, in accordance with themanufacturer’s recommendations.
4.3 Fabrication
Prepare and comply with proper fabrication procedures to SO’s acceptance, toensure achievement of the desired quality.
NPQSC5-10 Structural Steelwork
Version 1.0Page 13
4.3.1 Cutting
Comply with BS 5950-2 Clause 3.3 (Cutting).
Cut and shape steel by sawing, shearing, cropping, nibbling, plasma or laser cuttingand thermal or flame cutting.
Thermal cutting are not permitted at the areas indicated in the PSD.
Thermal cutting are not permitted at the following areas:
a. ____
b. ____
4.3.1.1 Hand Flame Cutting
Use only where it is impractical to use machine flame cutting.
4.3.1.2 Flame Cut Edges
Flame-cut edges that are free from significant irregularities require no furthertreatment other than dressing as specified in 4.3.3(Dressing).
4.3.2 Holing
Comply with BS 5950-2 Clause 3.4 (Holing).
4.3.2.1 Forming
Drill, punch, plasma or laser cut and thermal or flame cut round holes for fasteners.
Thermal holing or full size hole punching are not permitted at the areas indicated inthe PSD.
Thermal holing or full size hole punching are not permitted at the following areas:
a. ____
b. ____
4.3.2.2 Matching
Ensure all matching holes are formed such that fasteners can be inserted freelythrough the assembled members at right angles to the contact faces.
Drifting to align holes may be used provided it neither enlarges nor distorts the holes.
4.3.2.3 Drilling through Multiple Thickness
Tightly clamp the separate parts before drilling and remove any burrs after separatingthe parts.
4.3.2.4 Punching Full Size
Punching of full size holes is permitted when all the following conditions are satisfied:
a. The tolerance on distortion of the punched hole does not exceed that specified;
b. The holes are free of burrs which would prevent solid seating of the parts whentightened;
c. The thickness of the material is not greater than 30mm, nor greater than thediameter of the hole being punched;
NPQSC5-10 Structural Steelwork
Version 1.0Page 14
d. In spliced connections when the holes in mating surfaces are punched in thesame direction and the splice plates marked to show the assembly faces, ifpacked separately.
4.3.2.5 Punching and Reaming
When the conditions in 4.3.2.4 is not satisfied, punching is still permitted provided thatthe holes are punched at least 2mm less in diameter than the required size and theholes are then reamed to the full diameter after assembly.
4.3.3 Dressing
4.3.3.1 Removal of Burrs
Dress cut edges or holes to remove dross, burrs, irregularities and protruding edges.
If holes are drilled through components that are clamped together not intended to beseparated after drilling, removal of burrs is not required.
4.3.3.2 Dressing of Sharp Edges
Dress all sharp edges.
A 90° rolled, sheared or machined cut edge requires no further treatment.
4.3.4 Curving and Straightening
Curve or straighten components during fabrication using mechanical means or thelocal application of heat.
4.3.4.1 Heating
Control the temperature carefully and do not let the temperature exceed 650°C.
4.3.4.2 Inspection
After the process is complete, visually inspect all welds within the area of curving orstraightening. Carry out non-destructive testing of welds, where directed.
4.4 Bolting
4.4.1 Hole Sizes for Bolting
4.4.1.1 Ordinary and HSFG Bolts
a. For bolts ≤ 24mm diameter, hole sizes are to be bolt diameter +2mm.
b. For bolts > 24mm diameter, hole sizes are to be bolt diameter +3mm.
4.4.1.2 Holding Down Bolts
Hole sizes are to be bolt diameter +6mm with sufficient clearance to ensure the boltcan be accommodated through the base plate when adjusted.
4.4.1.3 Fitted Bolts
Clearance of bolt in hole is not to exceed 0.3mm.
4.4.2 Ordinary Bolted Assemblies
4.4.2.1 Make-up of Bolt Assemblies
Refer to Clause 3.3.1(Ordinary Bolt Assemblies) for strength grade combination ofbolt/nuts/washers.
NPQSC5-10 Structural Steelwork
Version 1.0Page 15
4.4.2.2 Condition of Bolts
Bolt assemblies are to be in such condition immediately before installation that thenut turns freely on the bolt.
4.4.2.3 Differing Grades of Bolts
Unless otherwise agreed by the SO, do not use different bolt grades of the samediameter in the same structure.
4.4.2.4 Bolt Length
The length of bolt is to be such that at least one clear thread shows above the nutafter tightening, and at least one thread plus the thread run out is clear between thenut and the unthreaded shank of the bolt.
4.4.2.5 Washers
Use at least one washer placed under the nut or bolt head being rotated in each boltassembly where the rotation might damage the surface protective treatment on themembers being connected. Use a plate or heavy duty washer under the head and nutwhere the members being connected have oversize or slotted holes.
4.4.2.6 Taper Washers
Place under bolt heads and nuts bearing on surfaces sloping 3° or more from a planeat right angles to the bolt axis.
4.4.2.7 Galvanised Nuts
Check after galvanizing to ensure free running on the bolt. Re-tap nuts, if necessary,to ensure satisfactory tightening.
4.4.2.8 Tightening
Use power tools or by hand using appropriate spanners to BS 2583.
4.4.2.9 Locking of Nuts
Secure nuts used in connections subject to vibration or reversal of stresses to preventloosening. If not specified on the drawings, include the proposed method in theerection details.
4.4.2.10 Fit-up Using Ordinary Bolt Assemblies
Draw connected parts firmly together. If there is a remaining gap more than 2mm,which may affect the integrity of the joint, take the joint apart and insert a pack of thesame steel material.
4.4.2.11 Reaming
Reaming may be used where the connection design allows the use of larger diameterholes and bolts in cases where drifting would distort the steelwork.
4.4.3 High Strength Friction Grip Fasteners
4.4.3.1 Make-up of Bolt Assemblies
Refer to Clause 3.3.3(High Strength Friction Grip Fasteners) for strength gradecombination of bolt/nuts/washers.
Place the hardened washer under the nut or head being turned.
NPQSC5-10 Structural Steelwork
Version 1.0Page 16
4.4.3.2 Tightening
Use high strength friction grip bolts in compliance with BS 4604-1 or 2.
Use the torque control method, the part-turn method or direct tension indicators inaccordance with the manufacturer’s recommendations for tightening in compliancewith BS 4604-1.
4.4.3.3 Calibration of Torque Equipment
Calibrate torque devices at least once each shift.
Recalibrate where necessary in accordance with BS 4604.
4.4.3.4 Discarded Bolt Assemblies
If after tightening, a bolt or nut is slackened off for any reason, discard the completebolt assembly and do not re-use in the Works.
4.4.3.5 Fit-up Using High Strength Friction Grip Fasteners
Draw connected parts firmly together with all bolts partially tightened. If there is aremaining gap, take the joint apart and insert a pack of the same steel material beforecontinuing tightening.
4.4.3.6 Reaming
Reaming may be used where the connection design allows the use of larger bolts incases where drifting would distort the steelwork.
Demonstrate by calculation that the connection is adequate for the specified forces.
4.4.3.7 Faying Surfaces for HSFG Fasteners
Remove all mill-scale from the faying surfaces of friction grip joints.
Ensure the faying surfaces of friction grip joints are free of distortion, deformities orcontaminants, which may reduce the slip factor below the design value.
4.4.4 Slotted Holes Bolts
Where slotted holes are provided for movement connections ensure the joint is free tomove.
4.4.5 Holes in Hollow Sections
Seal bolt holes and vent holes in hollow sections to prevent the ingress of moisture.
If not specified on the design drawings, show the proposed method on the shopdrawings.
4.5 Welding
4.5.1 Welding Processes
Processes for Shielded metal arc welding (SMAW), submerged arc welding (SAW),gas metal arc welding (GMAW) except GMAW-S, short circuiting transfer and fluxcored arc welding (FCAW) which conform to all of the requirements of ANSI/AWSD1.1 Section 3 are deemed as pre-qualified and accepted for use without performingthe Welding Procedure Specifications (WPS) Qualification Tests.
Gas tungsten arc welding (GTAW), electro-slag welding (ESW) or electro-gas welding(EGW) and gas metal arc welding - short circuiting transfer (GMAW-S) are to conformto all of the requirements of ANSI/AWS D1.1 Section 4.
NPQSC5-10 Structural Steelwork
Version 1.0Page 17
4.5.2 Welding Supervisor
Carry out welding under the direction of a welding supervisor with appropriatequalifications.
4.5.3 Welding Procedures Specifications
4.5.3.1 Preparation
Prepare Written Welding Procedure Specification (WPS) in accordance withANSI/AWS D1.1 Section 4 Part B for acceptance by the Independent Inspection andTesting Agency.
4.5.3.2 Procedure Tests
All procedure tests conducted are to be witnessed by the Independent Inspection andTesting Agency.
4.5.3.3 Availability of Welding Procedure Specifications
Make WPS available to the welder, the SO and the Independent Inspection andTesting Agency prior to the commencement of the works.
4.5.3.4 Inspection and test plans
Submit all inspection and test plans for SO’s acceptance prior to carrying out weldingworks.
4.5.4 Assembly
4.5.4.1 Fit-up
Fit up joints to the dimensional accuracy in accordance with the following:
a. ANSI/AWS D1.1 Clause 3.9 (Fillet Weld Requirement) for Fillet Welding
b. ANSI/AWS D1.1 Clause 3.11 (Common Requirements of Partial and CompleteJoint Penetration Groove Welds) and Clause 3.12 (Partial Joint PenetrationRequirements) for Partial Penetration Butt Welding.
c. ANSI/AWS D1.1 Clause 3.11 (Common Requirements of Partial and CompleteJoint Penetration Groove Welds and Clause 3.13 (Complete Joint PenetrationRequirements) for Partial Penetration Butt Welding.
4.5.4.2 Temporary Welds and Tack Welds
Temporary welds are subject to the same welding procedure requirements as thefinal welds. Remove the temporary welds unless otherwise agreed by the SO. Makeflush the surface with the original surface after the removal.
Tack welds are subject to the same quality requirements as the final welds, with thefollowing exceptions:
a. Preheat is not mandatory for single-pass tack welds which are re-melted andincorporated into continuous submerged arc welds.
b. Discontinuities, such as undercut, unfilled craters and porosity need not beremoved before the final submerged arc welding.
c. Tack welds, which are incorporated into the final weld, are to be made withelectrodes meeting the requirements of the final welds and are to be cleanedthoroughly. Multiple-pass tack welds are to have cascaded ends.
NPQSC5-10 Structural Steelwork
Version 1.0Page 18
Remove tack welds, which are not incorporated into the final weld, unless otherwiseagreed by the SO.
4.5.4.3 Control of Distortion and Shrinkage
Procedure and sequence of welding is to be in accordance with ANSI/AWS D1.1Clause 5.21 to minimise distortion and shrinkage.
4.5.4.4 Temporary Attachments
Welding of temporary attachments required for fabrication or erection is to be carriedout in accordance with the requirements for permanent welds.
Remove after use where required by flame cutting or gouging at a point not less than3mm from the surface of the parent metal.
Grind flush and inspect the area visually.
Where the parent metal is more than 20mm thick, check by magnetic particle testingmethod inspection using the acceptance criteria stipulated in Clause Error!Reference source not found.(Non-Destructive Testing of Welds).
Do not remove temporary attachments by hammering.
4.5.5 Shear Stud Welding
4.5.5.1 Method
Fix shear studs in accordance with the manufacturer’s recommendations formaterials, procedures and equipment.
4.5.5.2 Welding Procedure Trial
Where required, carry out welding procedure trial of studs to demonstrate thesuitability of the proposed welding system and equipment before commencement ofthe work.
The trial is to use the materials and procedures proposed for the works. Test aminimum of ten studs in the trial.
During the work, at the commencement of each shift, each welder is to undertake aminimum of two trial welds.
4.5.5.3 Visual Inspection
Visually inspect all studs. They are to exhibit full 360 degree ‘flash’ with no evidenceof undercut into the stud base.
4.5.5.4 Bend Test
Subject studs to bend tests at locations agreed with the SO.
Test at least 5% of studs and not less than two per beam.
Bend the head of the stud by striking the head of the stud to an angle ofapproximately 30° from their original axis with a hammer. Under this test the weld isto show no visible signs of cracking or lack of fusion.
Do not straighten any studs so tested.
4.5.5.5 Defective Studs
Replace any studs with defective welding and re-test as above.
Where defective studs are removed check the surface as specified in 4.5.5.3 above.
NPQSC5-10 Structural Steelwork
Version 1.0Page 19
4.5.6 Removal of Slag
Remove slag by light hammering, wire brushing or other means that do not deformthe surface of the weld.
4.6 Permitted Deviations (PDs) of Fabrication
4.6.1 PDs in Rolled Components After Fabrication
4.6.1.1 Cross Section After Fabrication
In accordance with the appropriate standards given in clause 3.1.1(Material Qualities)
4.6.1.2 Squareness of Ends not Prepared for Bearing
PD = D/300, where D is the depth of the section.
= D/300D
Plan or Elevation of End
4.6.1.3 Squareness of Ends Prepared for Bearing
PD = D/1000, where D is the depth of the section and the deviation is measuredrelative to the longitudinal axis of the member.
D
= D/1000
Plan or Elevation
90°
4.6.1.4 Straightness
PD of a member from a straight line drawn between adjacent points of subsequenteffective lateral restraint = 3mm or L/1000, whichever is greater, where L is thedistance between restraints.
L
= L/1000 or 3mmwhichever is the greater
4.6.1.5 Camber
PD from specified or proposed camber at mid-length = 6mm or L/1000, whichever isgreater, where L is the length of the member.
NPQSC5-10 Structural Steelwork
Version 1.0Page 20
L
whichever is the greaterDeviation = L/1000 or 6mm
Deviation
4.6.1.6 Length
PD after cutting, measured on the centre line of the section or on the corner of angles= 2mm.
= 2mm
L ±
4.6.2 PDs of Fabricated Components
4.6.2.1 Position of Fittings
PD from the intended position for fittings and components whose location is critical tothe force path = 3mm.
= 3mm
4.6.2.2 Position of Holes
PD from the intended position of hole or group of holes = 2mm.
= 2mm
4.6.2.3 Punched Holes
Distortion caused by a punched hole is not to exceed D/10 or 1mm, whichever isgreater, where D is the nominal hole diameter.
NPQSC5-10 Structural Steelwork
Version 1.0Page 21
whichever is the greater= D/10 or 1mm
D
4.6.2.4 Sheared or Cropped Edges of Plates or Angles
Deviation from a 90° edge is not to exceed t/10 where t = plate thickness.
= t/10
t
4.6.2.5 Flatness
Gaps in joints that depend on contact bearing when assembled during fabrication arenot to exceed 0.75mm and are to be less than 0.25mm over 50% of the length ofcontact of the section.
=0 75mm
4.6.3 PDs in Plate Girder Sections
4.6.3.1 Depth
PD measured on centre line = ± 4mm.
D ±
= 4mm
4.6.3.2 Flange Width
For flange width B < 300mm, PD = ±3mm.
For flange width B≥ 300mm, PD = ±5mm.
NPQSC5-10 Structural Steelwork
Version 1.0Page 22
B ±n
B ±w B or B <w n 300
= 3mm
B or B >w
= 5mm
300n _
4.6.3.3 Squareness of Sections
For flange width B, PD on out of squareness = B/100 or 3mm, whichever is greater.
B Flange width
= B / 100 or 3mmwhichever isthe greater
4.6.3.4 Web Eccentricity
PD on intended position of web from one edge of flange = ± 5mm.
= 5mmb
±
4.6.3.5 Flanges
For flange width B, PD on out of flatness = B/100 or 3mm, whichever is greater.
B Flange width
= B/100 or 3mmwhichever is the greater
4.6.3.6 Top Flange of Crane Girder
PD on out of flatness where rail seats = 1mm.
w = Rail width + 20mm
= 1mm
w w
4.6.3.7 Length
PD on length on centre line = ± 3mm.
NPQSC5-10 Structural Steelwork
Version 1.0Page 23
L ±
= 3mm
4.6.3.8 Flange Straightness
PD on straightness of individual flanges = L/1000 or 3mm, whichever is greater,where L is length.
L
whichever is the greater= L/1000 or 3mm
4.6.3.9 Curve or Camber
PD on intended curve or camber at mid-length of curved portion = L/1000 or 6mm,whichever is greater, where L is length and deviation is measured with webhorizontal.
Deviation
Deviation = L/1000 or 6mmwhichever is the greater
L
4.6.3.10 Web Distortion
PD on distortion on web depth (or gauge length) = d/150 or 3mm, whichever isgreater, where d is depth of web.
d
gauge length = web depth
= d/150 or 3mmwhichever is the greater
4.6.3.11 Cross Section at Bearings
PD on squareness of flanges to web = D/300 or 3mm, whichever is greater, where Dis depth of section.
D
= D/300 or 3mmwhichever is the greater
4.6.3.12 Web Stiffeners
PD on straightness of stiffener out of plane with web after welding = d/500 or 3mm,whichever is greater, where d is depth of stiffener.
NPQSC5-10 Structural Steelwork
Version 1.0Page 24
whichever is the greater= d/500 or 3mm
d
PD on straightness of stiffener in plane with web after welding = d/250 or 3mm,whichever is greater, where d is depth of stiffener.
= d/250 or 3mmwhichever is the greater
d
4.6.4 PDs in Box Sections
4.6.4.1 Plate Widths
For Bf or Bw < 300mm, PD = ±3mm, where Bf , Bw are flange width and web depthrespectively.
For Bf or Bw ≥ 300mm, PD = ± 5mm.
B ±w
B ±f
w B or B < 300f
= 3mm
= 5mm
B or B > 300f w
_
4.6.4.2 Squareness
PD on squareness measured at diaphragm positions = D/300, where D is sectiondepth.
D
= D/300
4.6.4.3 Plate Distortion
PD on distortion on width or gauge length = w/150 or 3mm, whichever is the greater,where w is depth of web.
NPQSC5-10 Structural Steelwork
Version 1.0Page 25
w
gauge length = width, w
= w/150 or 3mmwhichever is the greater
4.6.4.4 Web or Flange Straightness
PD on straightness of individual web or flanges = L/1000 or 3mm, whichever is thegreater, where L is full length.
whichever is the greater= L / 1000 or 3mm
L
4.6.4.5 Web Stiffeners
PD on straightness in plane with plate after welding = d/500 or 3mm, whichever is thegreater, where d is depth of web.
whichever is the greater= d / 500 or 3mm
d
PD on straightness out of plane to plate after welding = d/250 or 3mm, whichever isthe greater, where d is depth of web.
whichever is the greater
d
= d / 250 or 3mm
4.6.4.6 Length
PD on length measured on centre line = ± 3mm.
L ±
= 3mm
NPQSC5-10 Structural Steelwork
Version 1.0Page 26
4.6.4.7 Curve or Camber
PD on deviation from intended curve or camber at mid-length of curved portion whenmeasured with the un-cambered side horizontal = L/1000 or 6mm, whichever is thegreater, where L is length of the curved portion.
Deviation = L / 1000 or 6mmwhichever is the greater
L
Deviation
4.7 Erection
4.7.1 General
Prepare and comply with proper erection procedures to SO’s acceptance, to ensureachievement of the desired quality and safety, paying attention to site conditions,constraints and restrictions.
4.7.2 Erection Loads
Ensure that the structure is not overloaded by stacking of materials.
4.7.3 Temporary Supports
Any temporary supports used may be removed after the structure has been lined,levelled and plumbed, provided sufficient components have been erected andsecured to ensure the overall structure remains stable under the worst anticipatedconditions of loading.
4.7.4 Alignment
Align each part of the structure as soon as practicable after erection. Do not makepermanent connections between members until the structure has been sufficientlyaligned, levelled, plumbed and temporarily connected so that members will not bedisplaced during subsequent erection or alignment of the remainder of the structure.
4.7.5 Temperature Adjustment
Take due account of the effects of temperature on the structure and measuringequipment when measurements are made for setting-out and erection, and fordimensional checks carried out subsequently.
Adopt 30°C as the reference temperature unless otherwise agreed.
4.7.6 Site Welding
Carry out site welding only by agreement with the SO or as shown on the designdrawings.
Carry out all site welding in accordance with clause 4.5(Welding) above.
Do not carry out site welding in inclement weather unless adequate weatherprotection is provided for welders and materials.
NPQSC5-10 Structural Steelwork
Version 1.0Page 27
4.7.7 Foundation Bolts
Hold foundation bolts firmly in position during all setting-in operations.
Protect bolts, threads and nuts against damage, corrosion and contamination at allstages of construction.
Keep pockets formed around foundation bolts clean and free from all extraneousmatter.
Use templates to set in the holding-down bolts.
4.7.8 Packs and Wedges
Plumb and level columns using steel packs and wedges of adequate strength andstiffness, and not larger than necessary for the purpose.
Where packings are to be left in position and subsequently grouted, place them suchthat they are totally enclosed by the grout.
4.7.9 Grouting
Carry out grouting in accordance with BS 5950-2 Clause 6.3.
Do not carry out grouting under column base plates until a sufficient portion of thestructure has been aligned, levelled, plumbed and adequately braced.
Immediately before grouting, clean the space under the column base plates to be freeof all extraneous matter.
Prepare, mix and place proprietary grout in accordance with the manufacturer’srecommendations.
4.7.10 Profiled Steel Decking
Install in accordance with manufacturer’s recommendations, including the provision ofedge trims, temporary supports, lapping, etc.
4.8 Permitted Deviations (PDs) in Erection
Erect steelwork within the PDs in the following clauses.
4.8.1 Receiving Structures and Connections
Ensure that structures by others to which the steelwork attaches is constructed withinthe anticipated PDs before commencing steel erection.
Where components and fixings are cast in by others ensure that they are also withinthe anticipated PDs before commencing steel erection.
Inspect for position and level in good time before the planned start of steelworkerection.
In the event of any discrepancies found, notify the SO, propose and correct thediscrepancies.
4.8.2 PDs of Holding Down Bolts
4.8.2.1 Bolts or Bolt Groups with Allowance for Adjustment
a. Bolt level: +25/-5mm.
b. Minimum clearance: 25mm at top of concrete
NPQSC5-10 Structural Steelwork
Version 1.0Page 28
c. Bolt centroid: ±10mm from specified position at top of concrete.
of concreteclearance at top25 mm minimum
at top of concrete= ± 10 mm from specified position
bolt level- 5 mm+ 25 mm
=
4.8.2.2 Bolts or Bolt Groups with No Allowance for Adjustment
a. Bolt level: +45/-5mm.
b. Bolt centroid: ±3mm from specified position at top of concrete.
= ± 3 mm from specified position
bolt level= + 45 mm
- 5 mm
at top of concrete
4.8.2.3 Bolts or Bolt Groups Cast into Walls (No Allowance for Adjustment)
a. End of bolt: +45/-5mm.
b. Bolt centroid: ±3mm position in plan and elevation.
and elevationposition in plan= ± 3 mm
= bolt level+ 45 mm
- 5 mm
4.8.3 PD of Level of Base Plate
PD of level of column base plate = 5mm.
4.8.4 PDs of Erected Components
4.8.4.1 Position of Columns at Base
PD of section centreline from the specified position = 10mm.
= 10mm
4.8.4.2 Overall Plan Dimension
PD on length or width = 20mm for L < 30m and [20 + 0.25 (L-30)] mm for L ≥ 30m,where L is the specified overall dimension in metres.
NPQSC5-10 Structural Steelwork
Version 1.0Page 29
4.8.4.3 Plumb of Single Storey Columns
PD of top relative to base = ± h/600 or 5mm, whichever is greater, on main axes,excluding portal frame columns, where h is the storey height.
HH
= ± H/600 or 5 mm
Max = ± 25mm
whichever is greater
4.8.4.4 Plumb in Multi Storey Columns
PD in each storey of column = h/600 or 5mm, whichever is greater, where h is thestorey height.
PD of column at top storey relative to specified position at base plate = 50mmmaximum.
H = 50mm maximum
h = ± h/600 or 5 mm
h
h = storey height
H
whichever is greater
4.8.4.5 Alignment of Adjacent Perimeter Columns
PD of one column relative to the next on a line parallel to the grid line = 10mm whenmeasured at the base or splice level.
= 10 mm
critical face of columns
4.8.4.6 Gap Between Bearing Surfaces
PD = (D/1000 +1) mm where D is the dimension along the bearing surface.
= (D / 1000) + 1 mm
D
D
4.8.4.7 Level of Beams
a. PD of two or more beams meeting at a column = ± 5mm.
NPQSC5-10 Structural Steelwork
Version 1.0Page 30
= ± 10mm
SpecifiedLevel
b. PD on level of beam at its ends = 5mm.
= ± 5mm
c. PD on level of adjacent beams within a distance of 5m = ± 5mm.
= ± 5mm
d. PD from specified level of beam at supporting column = ± 10mm.
LevelFloor
h<3m, = 5mm
h<3m, = h/600
h
FloorLevel
e. PD of beam relative to adjacent beam above or below = 5mm for h < 3m andh/600 for h ≥ 3m, where h = storey height in m.
4.8.4.8 Plumb of Crane Gantry Columns
PD = ± Hc/1000 or 5mm, whichever is greater to a maximum of ± 25mm.
Hc
= ± H /1000 or 5mmcwhichever is greater
Max = ± 25mm
4.8.4.9 Crane Gantries Gauge of Rail Tracks
PD from true gauge = ± 10mm.
NPQSC5-10 Structural Steelwork
Version 1.0Page 31
= ± 10mm
G + H
4.8.4.10 Joints in Gantry Crane Rails
a. PD on rail surface across joint = 0.5mm.
= 0.5mm
b. PD on rail edge alignment across joint = 1mm.
= 1mm
4.8.4.11 Profile Steel Floor Decking
PD of dimension between deck edge trim and perimeter beam = ± 10mm for deckspan in either direction.
x ±
either directiondeck may spanGeneric profile
= ± 10mm
LCActual beam
lineGrid
4.8.5 Deviations Exceeding PDs
Inform the SO as soon as possible if checks show that the deviation in position of thesteelwork as erected exceeds the PDs given above. Propose and carry out remedialmeasures as required.
NPQSC5-10 Structural Steelwork
Version 1.0Page 32
5. VERIFICATION AND SUBMISSIONS
5.1 Submission
5.1.1 Design Submission
When required in Clause 1.4.1, submit to the SO for acceptance calculations anddrawings for the connection details within time as directed by the SO prior tocommencement of the Works.
5.1.2 Shop Drawings
Submit to the SO for acceptance complete and coordinated shop drawings withintime as directed by the SO prior to commencement of any works. Include all details ofthe steel structures incorporating at least the following information:
a. Number of pieces of steel sections
b. Dimensions
c. Tolerances
d. Connection details
e. Bearing locations and details
f. All other fabrication and erection details
5.1.3 Method Statement
Provide a detailed method statement to the SO for acceptance within directed timeprior to commencement of any works. Include at least the following information:
a. A site plan showing the work layout area, position and type of cranes, accessroutes, datum level, setting-out lines, storage area, etc.
b. Fabrication procedure/manual, locations (local and/or overseas), list ofsubcontractors/suppliers and their scope of works, quality assurance system, etc.
c. Storage and handling.
d. Maximum size of structural steel components that can be delivered to the site.
e. Assembly of structural members on the ground level before erection, wherepartial or complete fabrication work is required on site.
f. Sequence and method of erection and assembly of structural members takinginto account the site conditions, site constraints, site restriction and interface withother trades.
g. Detailed drawings and calculations for temporary works.
h. Details of proposed site inspection systems by the Accredited Inspection Body.
i. Details of staging, platforms and weather protection where site welding is to takeplace.
j. Remedial procedures for damaged steelwork during fabrication, transportation,storage, handling and erection.
k. Safety procedures for handling and erection of steelwork on site.
NPQSC5-10 Structural Steelwork
Version 1.0Page 33
5.1.4 Construction Information
Provide the following information within time as directed by the SO prior tocommencement of the Works:
a. Welder qualification records, welding procedure records, stud welding procedurerecords.
b. Details of welding procedures in accordance with ANSI/AWS D1.1 for all welds,including tack and sealing welds.
c. Details of proposed shop inspection system by the Independent Inspection andTesting Agency.
5.1.5 Programme
Provide a detailed programme to show the planned timing of the various items ofwork to be done within time as directed by the SO, including:
a. Preparation and submission of construction information
b. Order and delivery of materials
c. Fabrication
d. Application of protective coatings
e. Transportation to site
f. Erection
Include in the programme, the time required for all procedural trials, inspection andtesting, and trial assemblies.
5.1.6 Material Certificates
Submit to the SO for acceptance, material certificates duly verified by theIndependent Inspection and Testing Agency within time as directed by the SO prior tocommencement of any work.
5.1.6.1 Mill Certificates
Provide mill certificates for every batch of supply confirming compliance with thespecified standards before the supply of material to the works.
5.1.6.2 Test Certificates/Reports for Bolts and Inserts
Provide test certificates/reports and demonstrate by testing on 2% of actual materialsused that bolts and inserts used in the Works conform to the specified requirements.
5.1.7 Inspection by ITA
Submit all reports from the Independent Inspection and Testing Agency to SOperiodically as agreed with the SO.
5.1.8 As-built Drawings
Submit as-built drawings to the SO for record upon completion of the Works. Includeinformation on all element type, sizes, position including deviation exceeding thepermitted PD if any, connection and assembly details, and protective works applied ifany.
NPQSC5-10 Structural Steelwork
Version 1.0Page 34
5.1.9 Quality Control Manual
Submit a Quality Manual containing a QA/QC programme for the Works to the SO foracceptance within directed time frame.
The Quality Manual is to include at least information on the following:
a. Quality policy
b. Organisation charts and responsibilities
c. Internal quality control and audits
d. Facilities and equipment
e. Calibration and testing of equipment
f. Testing and inspection procedures
Subcontractors and suppliers
5.2 Procedural Trial and Trial Assemblies
Carry out procedural trial and trial assemblies as agreed with the SO, including testson material and workmanship in accordance with the Specification, prior tocommencement of the Works. Give adequate period of notice as agreed with the SO.
Keep records of all tests and make them available to the SO and the IndependentInspection and Testing Agency for examination throughout the duration of the Works.
5.3 Inspection
5.3.1 Inspection of Accuracy of Fabrication and Erection
Provide inspection reports in agreed batches endorsed by the IndependentInspection and Testing Agency, verifying that the fabrication and erection of the workscomply with the specified requirements.
5.3.2 Visual Inspection of Welds
Carry out visual inspection over the full lengths of all welds prior to any Non-Destructive Testing (NDT).
Immediately examine any welds that will be covered up before loss of access.
The acceptance criteria for visual inspection are to be in accordance with ANSI/AWSD1.1 Table 6.1.
5.4 Non-Destructive Testing of Welds
5.4.1 Scope of Inspection
Carry out Non-Destructive Testing as tabulated below unless otherwise agreed.
Inspection requirements may be reduced by agreement with the SO based onsatisfactory performance in the initial tests.
Full Penetration Butt Welds Partial Penetration Butt Welds
NPQSC5-10 Structural Steelwork
Version 1.0Page 35
Examples:
Examples:
Thickness All thicknesses All thicknessesMT /PT
Frequency 50% (site welds 100%) 50% (site welds 100%)
Thickness tmax ≥ 3 mm tmax ≥ 3 mmUT /RT
Frequency 50% (site welds 100%) 50% (site welds 100%)
Fillet Welds
Examples:
Thickness Fillet weld size ≥ 3 mm
Frequency 10% (site welds 100% but longitudinal welds 0.5m in each 10m or partthereof)
Thickness Fillet weld size ≥ 20 mm
MT / PT
Frequency 20% (site welds 100% but longitudinal welds 1.0m in each 10m or partthereof)
UT / RT As directed by SO
5.4.2 Hold Time Prior to NDT
For welds subject to NDT, carry out the testing at least 24 hours after the completionof the welds. For quenched and tempered steel, carry out NDT not less than 48 hoursafter the completion of the welds.
5.4.3 Magnetic Particle Testing (MT) and Penetrant Testing (PT)
Where magnetic particle testing (MT) is required in accordance with Clause5.4.1(Scope of Inspection), the procedure and technique are to be in accordance withASTM E709.
If Magnetic Particle testing is impractical, use Penetrant testing in accordance withthe procedure and technique given in ASTM E165.
5.4.4 Ultrasonic Examination (UT)
Where ultrasonic testing is required in accordance with Clause 5.4.1(Scope ofInspection), the procedure and technique are to be made in accordance withANSI/AWS D1.1 Section 6 Part F.
If ultrasonic testing is impractical, for example when the plate thickness is less than8mm, use radiographic testing in accordance with the procedure and technique givenin ANSI/AWS D1.1 Section 6 Part E.
NPQSC5-10 Structural Steelwork
Version 1.0Page 36
5.4.5 Radiographic Examination (RT)
Where radiographic testing is required in accordance with Clause 5.4.1(Scope ofInspection), the procedure and technique are to be in accordance with ASTM E94and ASTM E747.
5.4.6 Acceptance Criteria and Corrective Actions
Acceptance criteria are to be in accordance with ANSI/AWS D1.1 Section 6 Part C.Propose corrective actions to the SO for acceptance if the welds do not conform tothe acceptance criteria.
5.4.7 Weld Test Records
Record the results of all visual inspections and non-destructive testing and make allrecords available for inspection.
Recommended