051200 st structural steel framing

Work Package 4 Abu Dhabi Plaza, Astana, Kazakhstan

FOR TENDER

13.06.12

05 12 00 Structural Steel Framing R2

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Works Tender No. A560101/2011/T/014

Parts 2 Volume 2 Specifications

CONTENTS

1 GENERAL 41.1 SUMMARY 41.2 SUBMITTALS 81.3 CLOSEOUT SUBMITTALS 121.4 QUALITY ASSURANCE 121.5 DELIVERY, STORAGE, AND HANDLING 131.6 ENVIRONMENTAL CONDITIONS 152 PRODUCTS 152.1 STRUCTURAL STEEL MATERIALS 152.2 BOLTS, CONNECTORS, AND ANCHORS 192.3 PRIMER 222.4 GROUT 232.5 FABRICATION 242.6 SHOP CONNECTIONS 262.7 SHOP PRIMING 282.8 GALVANIZING 292.9 SOURCE QUALITY CONTROL 293 EXECUTION 303.1 EXAMINATION 303.2 PREPARATION 303.3 ERECTION 303.4 FIELD CONNECTIONS 333.5 PREFABRICATED BUILDING COLUMNS 383.6 FIELD QUALITY CONTROL 393.7 INSPECTION AND QUALITY CONTROL 433.8 REPAIRS AND PROTECTION 47

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SECTION 05 12 00 SRUCTURAL STEEL FRAMING

1 GENERAL 1.1 SUMMARY The Contractor shall provide structural steel as shown on the Contract Drawings, specified herein, and needed for a completed and proper installation. The Contract Drawings referred to in these Contract Documents and those subsequently provided are intended to indicate the outline of the structure, related elements and structural members to be employed and the standard of detail required. After consideration of all criteria and his own production arrangements, the Contractor may make proposals for changes in any of the details, sizes or materials shown or referred to in the Contract Documents. However such change shall be only limited to the extent that they do not change the stiffness and behaviour of the structure and may only be deemed acceptable if approved by the Engineer. If the changes suggested by the Contractor are of such nature that they affect the structural stiffness and behaviour significantly then the Contractor shall be responsible for carrying out the independent Wind Tunnel Test from the prior approved agency to arrive at the appropriate wind loads on the structure. All expenses towards such tests and all associated consultancy changes shall be borne by the Contractor. A. Section Includes: 1. Structural steel. 2. Prefabricated building columns. 3. Grout.

B. Related Sections:

1. 05 12 23 Structural Steel for Buildings 2. 05 21 00 Steel Joist Framing 3. 05 31 00 Steel Decking 4. 05 31 13 Steel Floor Decking 5. 05 42 00 Cold-Formed Metal Joist Framing 6. 03 00 00 Cast in-place concrete 7. 05 80 00 Corrosion Protection for Structural Steel

Note: With the exception of CSI Specifications 03 00 00 and 05 80 00 which are provided as separate documents. The information provided in the above sections is covered in this Specification but they CSI section listed have not been issued as separate documents as part of this tender submission. If the specified standards are withdrawn or superseded by new standards, with the prior approval of the Engineer, the Contractor may follow provisions of the new standard provided the quality of the works is not compromised.

C. REFERENCES

I. Contract Drawings and general provisions of the Contract, including General and Supplementary Conditions apply to this Section.

II. The British Standards referred to below, together with all appropriate references listed within

those Standards, shall be used with this Specification. The edition to be used shall be that current with all amendments as published at the date of this Specification, except that the latest editions of Standards may be used when no reduction in quality will result. Any differences between their requirements and this Specification shall be submitted to the

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Engineer for his ruling. Where a Standard has been specified an equivalent internationally recognized Standard, such as ASTM or DIN, may used subject to the Engineers approval.

BS 4 Structural steel sections

Part 1 : Specification for hot rolled sections

BS 449 The use of structural steel in buildings Part 2 : Metric units

BS 639 Covered carbon and carbon manganese steel electrodes for manual metal

BS 1133 Packaging Code Section 6 Temporary protection of metal surfaces against corrosion (during transport and storage)

BS 1449 Steel plate sheet and strip. Part 1: Section 1.12: Tolerances on dimensions and shape for hot-rolled narrow strip.

BS 1763 Thin PVC Sheeting (calendared, flexible unsupported)

BS 2600 Method for radiographic examination of fusion welded butt joins in steel Part 1 : 2mm up to and including 50mm thick Part 2 : Over 50mm up to and including 200mm thick

BS 2853 The design and testing of steel overhead runway beams

BS 2910 Methods for radiographic examination of fusion welded circumferential butt joints in steel pipes

BS 2994 Specification for cold rolled steel sections

BS 3643 ISO Metric screw threads Part 1 Principles and basic data Part 2 Specification for selected limited of size

BS 3692 ISO Metric precision hexagon bolts, screws and nuts

BS 3923 Methods for ultrasonic examination of welds Part 1 : Manual examination of fusion welds in ferritic steels Part 2 : Automatic examination of fusion welded butt joints in ferritic steels

BS 4165 Electrode wires and fluxes for the submerged arc welding of carbon steel and medium tensile steel

BS 4190 ISO Metric black hexagon bolts, screws and nuts

BS 4320 Metal washers for general Engineering purposes

BS 4360 Weldable structural steels

BS 4395 High strength friction grip bolts and associated nuts and washers for structural Engineering Part 1 : General grade

BS 4604 The use of high strength friction grip bolts in structural steelwork Part 1 : General grade

BS 4848 Hot rolled structural steel sections Part 2 : Hollow sections

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BS 4872 Approval testing of welders when welding procedure approval is not required Part 1 : Fusion welding of steel

BS 4933 ISO Metric black cup and countersunk head bolts and screws with hexagon nuts

BS 5135 Arc welding of carbon and carbon manganese steels

BS 5289 Visual inspection of fusion welded joints

BS 5400 Steel, concrete and composite bridges Part 10: Code of practice for fatigue

BS 5531 Safety in erecting structural frames

BS 5950 Structural use of steelwork in buildings Part 1: Code of practice for design in simple and continuous construction: hot-rolled sections. Part 2: Specification for materials, fabrication and erection: hot-rolled sections.

BS 5996 Specification for acceptance levels for internal imperfections in steel plate, strip and wide flats, based on ultrasonic testing.

BS 6037 Permanently installed suspended access equipment.

BS 6072 Method for magnetic particle flaw detection

BS 6363 Welded cold formed steel structural hollow sections

BS 6443 Method for penetrant flaw detection

BS 6651 Code of Practice for protection of structures against lightning.

BS 6722 Recommendations for dimensions of metallic materials

BS 6780 Through thickness reduction of area of steel plates and wide flats.

BS 7079 Preparation of steel substrates before application of paints and related products

BS 7668 Weldable structural steels. Hot finished structural hollow sections in weather resistant steels.

BS EN 287 Approval testing of welders for fusion welding.

BS EN 288 Approval of welding procedures for metallic materials

BS EN 1011 Part 1 & 2

Welding Recommendations for welding of metallic materials

SCI Publication P161

Guide to Site Welding

BCSA Publication No 52/10

National Structural Steel work specification for Building Construction. (CE Marking Version)

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BS EN 1090-2 Part - 2

Execution of steel structures and Aluminium Structures.

BS EN ISO 5817 Welding Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding excluded)

BS EN 10021 General Technical delivery requirements for steel and iron products

BS EN 10025 Hot rolled products of non alloy structural steels. Technical delivery conditions

BS EN 10029 Tolerances on dimensions, shape and mass for hot rolled steel plates 3mm thick or above.

BS EN 10034 Structural steel I and H sections Tolerances on shape and dimensions.

BS EN 10045 Charpy impact test on metallic materials

BS EN 10051 Continuously hot rolled uncoated plate, sheet and strip of non-alloy and alloy steels - tolerances on dimensions and shape.

BS EN 10056 Structural steel equal and unequal leg angles

BS EN 10113 Hot rolled products in weldable fine grain structural steels

BS EN 10137 Plates and wide flats made of high yield strength structural steels in the quenched and tempered or precipitation hardened conditions.

BS EN 10147 Continuously hot dip zinc coated plate and strip

BS EN 10155 Structural steels with improved atmospheric corrosion resistance. Technical delivery conditions

BS EN 10160 Ultrasonic Testing of Steel Flat Product of Thickness Equal or Greater Than 6 mm (Reflection Method)

BS EN 10164 Steel products with improved deformation properties perpendicular to the surface of the product. Technical delivery conditions

BS EN 10204 Metallic products. Types of inspection documents.

BS EN 10210 Hot finished structural hollow sections in non-alloy and fine grain structural steels. Part 1: Technical delivery requirements Part 2: Dimensions, tolerances & sectional properties

BS EN 22553 Welded, brazed and soldered joints. Symbolic representation on drawings

SNiP Standards

SNIP 11-23-81 Standards for Design Works Part 11:Steel structures

SP 53-102-2004 General regulations for designing steel structures

SNiP 2.03.11-85 Corrosion protection of building structures

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1.2 SUBMITTALS A. Product Data:

Submit two (2) copies, to the Engineer on demand, of the manufacturers test certificates (including mill reports) verifying that the materials comply with the relevant British Standards for all structural steel, bolting materials and welding consumables. B. Shop Drawings:

1) The Engineer will supply the Contractor with information necessary for the preparation of his drawings and

documents. If the Contractor discovers any contradiction or ambiguity in the information supplied by the Engineer then written clarification shall be obtained from the Engineer.

2) The Contract Drawings referred to herein and those subsequently provided are intended to indicate the

outline of the structure, related elements and structural members to be employed and the standard of detail required. After consideration of all criteria and his own production arrangements, the Contractor may make proposals for changes in any of the details, sizes or materials shown or referred to in the Tender documents. The shop drawings must show fabrication of structural-steel components and include;

a) Include details of cuts, connections, splices, camber, holes, and other pertinent data. b) Include embedment drawings. c) Indicate welds by standard BS EN 22553 symbols, distinguishing between shop and field welds, and

show size, length, and type of each weld. Show backing bars that are to be removed and supplemental fillet welds where backing bars are to remain.

d) Indicate type, size, and length of bolts, distinguishing between shop and field bolts. Identify pre-

tensioned and slip-critical high-strength bolted connections. e) Indicate locations and dimensions of protected zones.

f) Identify demand critical welds.

g) For structural-steel connections indicated to comply with design loads, include structural design data.

3) The Contractor shall provide the following documents:

a) Two (2) copies of marking plans and details for holding-down bolts, cast-in ferrules and other embedded items.

b) Two (2) copies of Shop Drawings. c) All connection details including calculations fully describing the method of connection design. Two (2)

copies of each revision of his shop drawings and calculations to the Engineer for review allowing 10 working days for each review. Additional copies of the connection design calculations and the shop drawings are to be provided for the approvals from authorities.

d) The shop drawings and calculations shall be prepared by suitably qualified personnel and they shall also be deemed to have undergone an internal check and been updated as necessary prior to this release for review. The Contractor's drawing register indicating current revisions is to be kept on site along with a full set of current drawings.

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e) Welding procedure details (including testing agency qualification certificates as well as welding certificates)

f) Fabrication method statement

g) Erection marking plans

h) Erection method statement including calculations The Erection method statement to be submitted within two (2) weeks of the acceptance of the works contract tender, including details of (with drawings as appropriate): - Method and sequence of erection - Allocation of cranage time required - Calculation of erection stresses - Details for any temporary works including fixing details needed to maintain stability during erection and until permanent works stability is complete, including temporary guys and bracing proposed for use during erection.

i) Details of the Quality Assurance Plan for structural steelwork together with full details of the stage control and inspection documents

h) As Built Drawings indicating survey information

4) Two (2) copies of each document shall be submitted to the Engineer for his approval and fabrication shall not be commenced until such approval has been given in writing. The drawings shall be submitted in related batches sufficiently in advance of the scheduled fabrication date to ensure that the Engineer has sufficient time and information to give full consideration to the proposals on the documents and for any changes to be incorporated and re-submitted for approval. Unless otherwise specified or agreed in writing, a period of at least 30 days shall be allowed from receipt of the documents by the Engineer to their return. These approval copies shall be additional to the number of copies of final drawings to be supplied.

5) All documents submitted for approval shall have already been checked by the Steelwork Contractor and

certified accordingly. 6) The Engineer will verify the correct interpretation of his requirements but is not responsible for verifying the

dimensions or checking the strength or practicability of the details. 7) Approval of the documents by the Engineer shall not relieve the Contractor of his obligations. The

Contractor shall be entirely responsible for his drawings including their accuracy (relative to the Engineer's Contract Drawings) the correctness of detail and the proper design of connections and joints and shall be responsible for any additional work required as a result of defects in his drawings.

8) Where the steelwork connects to an existing structure, the Contractor shall verify all dimensions that may

affect fabrication and notify the Engineer in writing of any discrepancies before fabrication commences.

C. Qualification Data: For qualified installer, fabricator, professional engineer and testing agency.

D. LEED Submittals: Refer to section on LEED requirements in Tender Documentation.

E. Welding certificates.

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F. Paint Compatibility Certificates: From manufacturers of topcoats applied over shop primers, certifying that shop primers are compatible with topcoats.

G. Mill test reports for structural steel, including chemical and physical properties.

H. Product Test Reports: For the following (but not limited to):

I. Bolts, nuts, and washers including mechanical properties and chemical analysis.

II. Direct-tension indicators.

III. Tension-control, high-strength bolt-nut-washer assemblies.

IV. Shear stud connectors.

V. Shop primers.

VI. Non-shrink grout. I. Source quality-control reports.

J. Design

I. The structural steelwork shown on the Contract Drawings and described in this Specification has been designed to BS 5950 where applicable, unless stated otherwise.

II. Notwithstanding the details relating to the tender, the Contractor will be responsible for the complete design of member connections to BS 5950.

III. Steel grade(s) unless shown otherwise on the Contract Drawings:-

a) Sections other than hollow sections S355 to BS EN 10025;

b) Hollow sections S355 to BS EN 10210.

IV. The sub-grade of steelwork members shall be determined in accordance with the requirements of Cl 2.4.4, BS 5950.

V. Complete the design and detailing of connections to BS 5950 to satisfy loading requirements specified or otherwise calculable from the information given.

K. Connections and Joints

I. General

a) The Contractor shall design and detail all steel connections.

b) Where typical connections are shown on the Engineer's Drawings the Contractor shall satisfy himself

as to their practicability and he shall be at liberty to put forward alternative suggestions for their design.

c) All connections designed by the Contractor shall be submitted for the Engineer's review. The Contractor shall provide two (2) numbers of copies of each revision of calculations to demonstrate the adequacy of connections which he has designed. In addition to other loads, all connections shall be designed to resist construction loading.

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d) Connections shall be designed taking account of the effects of any eccentricity on the component parts of the connection, including welds and bolts.

e) The Contractor shall not introduce eccentricity into the layout of the members nor into the arrangement

of the connections except as agreed by the Engineer in writing.

f) Before commencing the workshop drawings the Contractor shall prepare and submit for the Engineer's approval drawings showing typical details proposed for the connections.

g) The Contractor shall meet the Engineer approximately 10 days after these drawings have been

submitted, at a time and place agreed by the Engineer, to review these drawings and co-ordinate the procedure for the approval of workshop drawings.

h) Simply supported end connections shall provide sufficient flexibility to accommodate the end rotation

of the beam. This flexibility may be provided by movement of bolts in clearance holes or by flexure of cleats or endplates. Care must be taken to ensure that the welds and bolts are strong enough to resist the forces necessary to produce such movement or flexure.

i) In cleated end connections of beams the cleats shall project 2mm beyond the end of the member

unless specified otherwise on the Contract Drawings. j) Load carrying connections shall have not less than two bolts of a size appropriate to the member or

else welds giving a similar capacity.

II. Welded Connections

a) In addition to meeting the requirements of BS 5950 Part 1, for the design of welds, the guidance given in Appendix A of BS 5135 shall be applied.

b) The dimensions of all welds shall be clearly specified on the working drawings using symbols in

accordance with BS 499, Part 2.

III. BOLTED CONNECTIONS

a) Unless specified otherwise preloaded high strength bearing type bolts shall be used for all connections to main structural members and trusses.

b) Unless specified otherwise, ordinary bolts in clearance holes tightened to the snug tight condition will

be acceptable for connections of such members as wind bracings, sheeting rails and purlins and for minor secondary members.

c) Nuts in connections subject to vibration shall be of the self-locking type or provided with lock-nuts,

except where high strength friction grip fasteners are used. d) Whenever bolted connections are used, the reduced sectional area of members shall be computed

and the members strengthened if required.

IV. Connections of Runway Beams and Trolley Beams:

a) Connections of runway beams shall comply with BS 2853. Special attention is drawn to the provisions of Appendix G of BS 2853 - see Amendment No. 3 (PD 6225). Connections of trolley beams for window cleaning trolleys and the like shall be designed as for runway beams.

L. Design Constraints

1. Unless required or permitted otherwise, comply with the following when completing the design and detailing

of the work:

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a) Position members forming bracing systems or girders of lattice construction so that their lines of action

intersect at a point. b) Bolts to be grade 8.8 and not less than 16 mm diameter. c) Not less than two bolts to be used in any connection. d) Weld leg length to be 6mm fillet weld minimum unless notes otherwise.

M. In order to meet the requirements for erection tolerances under final dead load, and the criteria of BS

5950 for deflections due to live loads, it will be necessary to pre-camber those members or pre-set those elements that would not otherwise comply. The amount of camber or pre-setting necessary to meet the requirements of this Specification shall be agreed with the Engineer and shall be shown on the shop drawings.

1.3 CLOSEOUT SUBMITTALS A. Section 01 78 00 - Execution and Closeout Requirements: Closeout procedures. 1.4 QUALITY ASSURANCE A. The Contractor shall operate a Quality Assurance System for all stages of the work and all work shall be

in accordance with that system. The Contractor shall have internationally acceptable accreditation to the approval of the Engineer.

B. The Contractor shall operate a Quality Assurance System for all stages of the work to the approval of the

Engineer and all work shall be in accordance with the requirements set out in Division 01 Section 01 40 00.

C. All workmanship, material and tests (where required) shall comply with the appropriate British Standard

and be in accordance with the Contract Drawings all to the satisfaction of the Engineer. D. Pre-installation Meeting: Conduct meeting at Project site. E. Any Approval by the Engineer does not relieve the Contractor of his responsibilities. F. COORDINATION

I. Coordinate selection of shop primers with topcoats to be applied over them. Comply with paint and coating manufacturers' recommendations to ensure that shop primers and topcoats are compatible with one another.

II. Coordinate installation of anchorage items to be embedded in or attached to other construction without

delaying the Work. Provide setting diagrams, sheet metal templates, instructions, and directions for installation.

G. INSPECTION AND TESTING

I. Carry out all inspection and testing in accordance with this section and the relevant standards.

II. In the event that materials or workmanship fail to comply with the requirements specified herein, carry out further inspection and testing to satisfy the Engineer. Testing laboratories shall be to the approval of the Engineer.

III. Carry out any additional inspection and testing required by the Engineer at Contractor cost.

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IV. Demonstrate to the Engineer that full records are maintained through all stages of the work. Make

these records freely available for inspection by the Engineer at any time.

V. For inspection timings refer to Appendices to Tender for normal working hours H. ACCEPTANCE OF THE ENGINEER

I. Obtain acceptance of the Engineer wherever required, in writing before the work is undertaken.

II. If any deviation is required from any part of this Specification, obtain such approvals in writing before proceeding with any such deviation.

I. PERFORMANCE REQUIREMENTS

I. Connections: Provide details of simple shear required by the Contract Documents to be selected or completed by structural-steel fabricator, including comprehensive engineering design by a qualified professional engineer, to withstand loads indicated and comply with other information and restrictions indicated.

II. Select and complete connections using schematic details indicated and BS 5950.

III. Moment Connections: Type PR, partially restrained and FR, fully restrained as applicable and as

indicated on the Contract Drawings.

IV. Construction: All frame types as applicable and as indicated on the Contract Drawings. J. DEFINITIONS

Structural Steel: Elements of structural-steel frame, as classified by BS 5950, "Code of Standard Practice for Steel Buildings" Part 1 and 2

I. Heavy Sections: Rolled and built-up sections as follows:

1. Shapes included in BS 4848 Part 4 and 5 with flanges thicker than 38 mm. 2. Welded built-up members with plates thicker than 50 mm. 3. Column base plates thicker than 50 mm.

II. Protected Zone: Structural members or portions of structural members indicated as "Protected Zone" on Contract Drawings. Connections of structural and non-structural elements to protected zones are limited.

1.5 DELIVERY, STORAGE, AND HANDLING A. Store materials to permit easy access for inspection and identification. Keep steel members off ground

and spaced by using pallets, dunnage, or other supports and spacers. Protect steel members and packaged materials from corrosion and deterioration.

I. Do not store materials on structure in a manner that might cause distortion, damage, or overload to members or supporting structures. Repair or replace damaged materials or structures as directed.

B. Store fasteners in a protected place in sealed containers with manufacturer's labels intact.

I. Fasteners may be repackaged provided Owner's testing and inspecting agency observes repackaging and seals containers.

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II. Clean and re-lubricate bolts and nuts that become dry or rusty before use.

III. Comply with manufacturers' written recommendations for cleaning and lubricating fasteners and for

retesting fasteners after lubrication.

C. Deliver materials to the job site properly marked to identify the location for which they are intended.

D. Use markings corresponding to markings shown on the approved Shop Drawings.

E. Store in a manner to maintain identification and to prevent damage. Each grade of steel shall be stored separately.

F. Particular care shall be taken when transporting, handling or storing parts which have been metal sprayed, galvanized or painted. If the coating is damaged it shall be restored to comply with the relevant requirements of Specification for Corrosion Protection for Steelwork.

G. Each type and grade of bolt and each type and grade of welding consumable shall be clearly identified and stored separately.

H. Each type of welding consumable shall be stored in environmental conditions suited to that type.

I. An assembly, which contains several loose parts, may be identified by a single tag or marking provided that the whole unit is put together before delivery in such a way that it will not accidentally fall apart.

J. Holding down bolts shall be delivered to site with the threads protected against corrosion with Type TP 4a Soft-film grease as specified in BS 1133: Section 6. Where specified metal sleeves shall be supplied in accordance with the Contract Drawings.

K. Fabricated parts shall be handled and stacked in such a way that permanent damage is not caused to the components. Means shall be provided to minimize damage to the protective treatment on the steelwork.

L. All work shall be protected from damage in transit. Particular care shall be taken to stiffen free ends, prevent permanent distortion, and adequately protect all machined surfaces. All bolts, nuts, washers, screws, small plates and articles generally shall be suitably packed and identified.

M. Do not allow components to swing freely. Use man-made fibre ropes, webbing or chains with clean,

undamaged heavy rubber sheathing to hold and guide the lift into place. N. The Contractor shall be responsible for the stability, adequacy, accuracy and correct assembly of the

structure during all stages of erection.

O. Throughout the erection of the structure, the steelwork shall be securely bolted or fastened in order to ensure that it can adequately withstand all loadings liable to be encountered during erection, including where necessary, those from erection plant and its operation.

P. Any temporary bracing or temporary restraint shall be left in position until such time as erection is sufficiently advanced so as to allow its safe removal.

Q. All connections for temporary bracing, bolts, members, etc, to be provided for erection purposes shall be made so that they do not weaken the permanent structure or impair serviceability.

R. Temporary bracing shall be positioned so as to cause the minimum of interference with other trades. Protection to temporary bracing shall conform to BS 5493.

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S. Temporary bracing shall be removed by the Contractor and the structure made good as deemed necessary by the Contract Administrator at the expense of the Contractor.

1.6 ENVIRONMENTAL CONDITIONS

Not Used.

2 PRODUCTS 2.1 STRUCTURAL STEEL MATERIALS A. Hot-rolled steel: All hot rolled sections must comply with the following BS.

I. BS-4: Structural steel sections, Part 1 : Specification for hot rolled sections

II. BS EN 10025: Hot rolled products of non alloy structural steels. Technical delivery conditions

III. BS5950 Part 1 Code of practice for design in simple and continuous construction: hot

rolled sections.

IV. Manufacturer:

V. Product reference:

VI. Material: As set forth in BS5950 Part-2.

VII. Thickness.

B. Cold-Formed Hollow Structural Sections: All cold formed section must comply with the following BS.

I. BS5950 Part 5 -Design of cold formed sections.

II. BS5950 Part 7- Specification for material and workmanship cold formed sections.

III. Manufacturer:

IV. Product reference:

V. Material: Galvanized steel sheet to BS EN 10147.

VI. Thickness.

VII. They shall be produced by a reputed manufacturer such as Metsec or equal approved.

They shall be designed and detailed by the Contractor.

C. Welding Electrodes:

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I. All electrodes shall have a yield strength, tensile strength, toughness and ductility not less than those specified for the grade of steel being welded.

II. Covered electrodes for manual metal-arc welding shall comply with the requirements of BS 639.

III. When weathering steel is to be welded the welding electrodes shall be of matching composition to the parent material.

a) Plate And Section

1. The dimensions of rolled steel sections shall comply with BS 4: Part 1 or BS 4848. Dimensional tolerances

shall comply with BS EN 10034 or BS EN 10056 as appropriate. The dimensional tolerances for flats round and square bars shall be as specified in BS EN 10025 Clause 2.2. The tolerances for plate and strip produced on continuous mills shall comply with BS EN 10051 or BS1449 as appropriate. Tolerances for plates produced by

non-continuous mills shall comply with BS EN 10029, and thickness class A tolerances shall apply. The tolerance over or under the nominal thickness shall be equal to half the total thickness tolerance.

2. All steel in plates and sections shall comply with the Standards listed in Table 1 as appropriate, except that

rimming steel shall not be used. Only new steel shall be used; the surface condition of steel shall be in accordance with subsection Fabrication - Surfaces.

Standard Product TypeBS EN 10025 Hot rolled products of non-alloy structural steels - Technical delivery

conditions. BS EN 10113 Parts 1, 2 & 3

Hot rolled products in weldable fine grain structural steels. Part 1 - General delivery conditions. Part 2 - Delivery conditions for normalised steels.

BS EN 10137 Hot rolled quenched and tempered weldable structural steel plates. BS EN 10210 Parts 1 & 2

Hot finished structural hollow sections of non-alloy and fine grain structural steels Part 1 - Technical delivery requirements Part 2 - Dimensions, tolerances & sectional properties

BS EN 10155 Structural steels with improved atmospheric corrosion resistance. Technical delivery conditions.

BS 7668 Weldable structural steels. Hot finished structural hollow sections in weather resistant steels.

Table 1: Standards Applicable to Various Products of Structural Steel

3. Except where noted or agreed otherwise, the particular grade of steel used shall be determined in accordance with BS 5950 Part 1 Section 2.4.4 adopting a value of K equal to one.

4. The Contractor shall ensure that the quality of the manufactured steel is in agreement with the aesthetic

appearance requirement of the structure. Where material is required 'free from laminations' it shall be tested in accordance with BS EN 10160 and agreed by the Engineer. All cap plates and end plates over 25mm thick are to be laminar free material.

5. Steel supplied to BS EN 10025 shall have the following options invoked by the Contractor at the time of

placing an order for the steel:-

a) Option 3: The method of deoxidation shall be as given in table 2 of BS EN 10025. b) Option 5: The carbon equivalent value shall not exceed the values given in table 4 of BS EN 10025. c) Option 7: The carbon content of steels type S355JO, S355J2, and S355K2 shall not exceed 0.18%

by ladle analysis.

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d) Option 9: The impact properties of quality JR material shall be in accordance with table 6 of BS

EN 10025 and shall be verified by test. e) Option 10: When required by this Specification, or when noted on the Contract Drawings, products

with improved properties perpendicular to the surface shall be supplied in quality class Z35 to BS EN 10164.

f) Option 11: Where steel products are to be hot-dip galvanised or hot enamelled then the steel

manufacturers shall be informed of the particular process in order that steel of a suitable condition is supplied.

g) Option 12: Specific inspection and testing shall be carried out for all steel products according to

the requirements of clauses 8.2 to 8.9 of BS EN 10025. The inspection document shall comprise the inspection certificates as defined in BS EN 10021.

h) Option 14: The verification of the mechanical properties for quality JR steels shall be carried out

by cast. i) Option 17: Flat products in grades S355JR and S355JO that are greater than 12.5mm thick shall

be supplied in a normalised or equivalent condition. Any flat product that will be subject to hot working during fabrication or erection shall be supplied in a normalised or equivalent condition. Quality grades J2G4 and K2G4 shall not be supplied as an option unless specified by the Engineer.

j) Option 22: Any long product that will be subject to hot working during fabrication or erection shall

be supplied in a normalised or equivalent condition.

k) Option 24: Where sections are to be split during the fabrication process then the steel producer shall be made aware of this requirement in order that steel of a suitable condition is supplied.

l) All plates for outrigger elements shall have option 4 of BS EN 10025 invoked and shall be delivered in accordance with BS EN 10164 quality class Z35.

m) All plates for outrigger elements shall be subjected to 100% UT inspection as defined in

BS EN 12062. The surface shall comply with BS EN 10160 Class S2 and E2. 6. Steel to BS EN 10113 Pt3 shall not be used unless specified by the Engineer, in which case the options

required for steel to Pts 1 & 2 shall be invoked. Steel to BS EN 10113 Pts 1 & 2 shall have to the following options invoked:-

a) Option 2: The carbon equivalent value shall not exceed the values given in table 2 of BS EN

10113 part 2 or 3 as appropriate. Unless agreed otherwise with the Engineer, prior to material ordering, the carbon equivalent value for steel grade S460 to Pt.2 shall be no greater than 0.51%.

b) Option 4: Only steel of designation NL shall be supplied unless otherwise specified by the

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d) Option 7: When steel products are to be hot-dip galvanised or hot enamelled then the steel manufacturer shall be informed of the particular process so that steel of a suitable condition is supplied.

e) Option 10: Hard stamping of steel shall not be allowed. f) Options 13 & 16: All steel products shall be free from internal defects that would exclude them

from being used for their intended purpose. When option 6 above applies options 13 and 16 shall also be invoked and ultrasonic testing shall be carried out to BS EN 10164 or Euronorm 186 as appropriate.

g) Option 15: Where sections are to be split during fabrication then the steel producer shall be made

aware of this requirement so that steel of a suitable condition is supplied.

7. Steel supplied to BS EN 10137 shall have the following options invoked:

a) Option 2: The product analysis shall be performed to check compliance with Table 1 of BS EN 10137 - part 2.

b) Option 5: When required by this Specification or when noted on the Contract Drawings, products


8. Steel supplied to BS EN 10210 Part 1 shall have the following options invoked.

a) Option 1.2 and 1.4: The carbon equivalent value shall not exceed the values given in tables A2 or B2 of BS EN 10210 Pt 1.

b) Option 1.6: The impact properties of quality JO and JR steel shall be verified by test and shall be

in accordance with tables A3 or B3 of BS EN 10210 Part 1. c) Option 1.7: Where steel products are to be hot dip galvanised then the steel manufacturer shall be

informed of the particular process in order that steel of a suitable condition is supplied. d) Option 1.9: Specific inspection and testing shall be carried out for all steel products in accordance

with clauses 7.1 to 7.3 of BS EN 10210 Part 1. The inspection document shall include an inspection certificate of type 3.1B to BS 10204.

9. Weathering steels supplied to BS EN 10155 shall have the following options invoked by the Contractor at

the time of placing an order for the steel:

a) Option 4: The carbon equivalent value for grade S355 steel shall be limited to a maximum of 0.52% and for grade S235 steel the CEV limit shall be 0.44%.

b) Option 6: The impact properties of all steels shall be in accordance with table 6 of BS EN 10155

and shall be verified by test. c) Option 7: Specific inspection and testing shall be carried out for all steel products according to the

requirements of clauses 8.2 to 8.9 of BS EN 10155. The inspection document shall comprise of the certificates as defined in BS EN 10021.

10. Steel supplied to BS 7668 shall have the following options invoked:

a) Option B4. The carbon equivalent value shall not exceed the value given in Table B1 of BS 7668.

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11. Steel castings and forgings shall comply with BS3100 and BS29 respectively and shall only be used when the use of such materials will not be detrimental.

2.2 BOLTS, CONNECTORS, AND ANCHORS A. Ordinary bolts and nuts shall comply with BS 3692, BS 4190 or BS 4395 Part 1 for hexagon headed

bolts or BS 4933 for cup headed or countersunk bolts. Unless otherwise specified bolts and nuts shall be of grade 8.8. Only one grade of steel shall be used for each diameter of bolt.

I. Ordinary washers shall comply with BS 4320. Plain washers shall be made of steel and

taper or other special shaped washers shall be of steel or malleable cast iron.

II. Bolting materials that have been sheradised or otherwise coated shall be manufactured and coated to give a satisfactory fit between the finished bolt and its nut.

III. High strength friction grip bolts, nuts and washers shall comply with BS 4395 Part 1.

IV. Galvanising, sheradising, or electroplating of nuts, bolts and washers shall be carried out only by the manufacturer of these items.

V. All bolts, nuts and washers shall be spun galvanised, or as otherwise approved. Prior to any work being undertaken the Contractor shall confirm in writing that the finish is compatible with the steel finish and the environment.

VI. Where specified, the nuts used on connections subject to vibration shall be secured to prevent loosening. Self locking nuts or an approved chemical product shall be used or else the nuts shall be secured by the use of locknuts. Where slotted holes are provided for movement connections the joint shall be free to move.

VII. When bolts are intended for use at service temperatures below -20 deg C, they shall have minimum impact strength of 27J in accordance with BS EN ISO 898-1 under such temperature as outlined in National Structural Steelwork Specification for Building Construction (NSSS), Clause 2.4.2.

B. Direct-Tension Indicators:

I. Standard: To BS 7644-1.

II. When placed under bolt head, prevent bolt turning when tightening.

III. When placed under nut, protect nibs with a hardened washer and prevent both washers from turning when tight.

IV. Manufacturer: to be agreed with the Contractor unless specified on the Contract Drawings.

V. Product reference: to be agreed with the Contractor unless specified on the Contract Drawings

VI. Grade: Appropriate for grade of bolt and nut assembly.

VII. Finish: Appropriate for specified bolt and nut assembly.

VIII. Ancillary components: Washers to BS 7644-2. Used as recommended in BS 7644-1, Annex A.

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IX. Post installation and inspection treatment: Where no further protective coating is specified, apply a butyl rubber sealing compound to seal measuring gap around indicators.

C. Shear Stud Specification:

I. Shear studs shall be in accordance with BS EN ISO 13918.

II. If required and unless stated otherwise on the Contract Drawings, shear studs are to be

proprietary studs manufactured from low carbon steel with a minimum yield point of 350N/mm2, ultimate tensile strength of 450N/mm2 and elongation of 15% on a gauge length of 5.65 A when tested in accordance with BS18. Shear Studs will have a shank diameter of 19mm and a height to suit the slab thickness with a minimum height of 100 mm after through deck welding.

D. Shear Stud Welding:

I. Welders to be certified by the equipment manufacturer or other recognised authority as

competent for the work.

II. Top surface of the flange to be free from mill scale, rust, grease, oil, paint and any other substance detrimental to welding. Ensure that flange is clean prior to laying decking.

III. Prefabrication primer and other paints should not be used in areas to be welded.

E. Shear Stud Testing

I. Before stud welding is commenced, the welding procedure should be checked by trial welding under site conditions. These trials should cover the full range of flange thicknesses and stud sizes to be used. Where welding through profiled steel sheets is required, this should be included in the welding trials.

II. In these trials a minimum of two studs should be welded for each case. These studs should be cold bent manually to an angle of 30 degrees by means of a 1.3m steel tube placed over the stud. Test bending should always be in the direction of the span of the beam. Hammer impact testing is not allowed. If failure occurs in the weld zone of either stud, the welding equipment should be adjusted and the test repeated.

III. All shear studs to be ring tested by tapping lightly with a small hammer. Properly welded studs will ring soundly whilst imperfectly welded studs will give dull sound.

IV. Any studs indicating weld implication should be tested to 15 degrees from the vertical. If the weld does not fracture, the stud should be considered acceptable. If the weld facture occurs a replacement stud should be fixed slightly away from the imperfect area

V. Sleeves: Bolt sleeves shall be made from mild steel sheet and shall not allow the passage of cement grout into the tube. The gauge thickness of steel appropriate to the sleeve diameter will be shown on the bolt schedules. The length of the sleeve shall be accurate within a tolerance of plus or minus 3mm and the diameter within plus or minus 5mm. The ends of a sleeve shall be square to its centre line.

F. Bolts

Cast-In Holding Down Bolts

I. For the purposes of this Specification the length of a holding down bolt shall be taken as

the overall length excluding the head (or clear of the bottom nut in the case of a fabricated

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bolt) i.e., the sum of the embedded length, the projecting length and the thickness of the anchor plate.

Manufactured Bolts

I. Bolts obtained from bolt manufacturers shall comply with the requirements of BS 3692 or BS 4190 as appropriate.

II. Nuts shall comply with the requirements of BS 3692 or BS 4190 as appropriate and shall be of at least the recommended strength grade corresponding to the strength grade of the bolts. Nuts shall be of normal standard thickness; thin nuts shall only be used as locknuts.

III. Unless specified otherwise bolts shall be of strength grade 4.6 with nuts of strength grade 4 or higher.

Fabricated Bolts

I. Where bolts are fabricated from plain round bar the threads shall be ISO metric, coarse pitch series, free fit as specified in BS 3643. Both ends shall be threaded and the nut at the bottom end shall be welded in place to prevent it from turning. The diameters used shall be those for standard bolts quoted in BS 3692 and BS 4190 as appropriate.

II. The weight of the bar shall be within plus or minus 2.5% of the weight appropriate to the true cross sectional area. The bolt shall be straight within a tolerance of 2mm per metre length of the bolt, with a minimum tolerance of 2mm. The overall length shall be accurate within a tolerance of plus or minus 3mm, the bottom nut being so positioned that the length shall be within a tolerance of minus zero and plus 5mm. The threaded length shall be accurate within a tolerance of minus zero and plus 20mm.

III. Nuts shall comply with the requirements of BS 3692 or BS 4190 as appropriate and shall be of a strength grade such that the specified proof load stress of the nut is not less than the specified minimum ultimate tensile strength of the bolt material, except that the nuts of strength grade 4 may be used with bolts of grade 43 steel to BS 4360. Nuts shall be of normal standard thickness; thin nuts shall only be used as locknuts.

IV. Unless specified otherwise, bolts shall be of grade 43 steel to BS 4360 with nuts of strength grade 8.8 or higher.

G. Anchor Plates:

I. Unless specified otherwise, anchor plates shall be fabricated from grade 43 steel to BS 4360. Anchor plates shall be accurate in plan size within a tolerance of minus zero and plus 10mm; the thickness of plate shall be within normal rolling margins as specified in BS 4360. Anchor plates shall be sufficiently flat and free from warping to prevent grout from entering at the bottom of the sleeve (if used). The positions of slugs welded to the underside of anchor plates shall be accurate within a tolerance of plus or minus 1.0mm.

H. Washer Plates:

I. The washer plates which are welded to the heads (or bottom nuts) of smaller diameter

bolts to prevent them from turning between the slugs on the anchor plate shall be grade 43 steel to BS 4360 unless specified otherwise. Washer plates shall be accurate in plan size within a tolerance of plus 2mm and minus 3mm and the corners shall be square within a tolerance of plus or minus 2. The thickness of plate shall be within normal rolling margins as specified in BS 4360. The plates shall be flat and free from warping.

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I. Washers:

I. Unless specified otherwise standard washers shall be normal diameter black mild steel washers to BS 4320. Where the holes in the base plate are larger than normal clearance holes, special washers will be required to details shown on the schedules; unless specified otherwise these special washers shall be fabricated from grade 43 steel to BS 4360.

2.3 PRIMER Comply with Section 099113 Part A

A. Finishes Generally:

I. Once applied the finish should not in any way slump, flow, crack, flake, split, sag, pit,

bubble, blister, float, effloresce, craze, shrink, break, wrinkle, or crinkle.

II. Thinners shall not be added to paint to change in any way its constitution or consistency unless agreed by the Engineer.

III. All finishes should be durable, of uniform texture and colour and should be resilient.

IV. All finishes should be uniform in texture, colour and appearance within the limits of the agreed samples and without irregularities or distortion. Finish coatings shall match the colour and gloss of the agreed control samples.

V. There shall be an interval of at least 24 hours between successive coats of painting or as recommended by the Engineer.

B. Suitability of Conditions:

I. Do not apply coatings:

a. To surfaces affected by moisture or frost.

b. Unless the steel temperature is at least 3C above the dew point with conditions

stable or improving.

c. Unless the relative humidity is below 85%.

d. When heat is likely to cause blistering or wrinkling.

e. Take all necessary precautions including restrictions on working hours, providing temporary protection and allowing extra drying time, to ensure that coatings are not adversely affected by climatic conditions before, during and after application.

f. Application of coatings will be taken as joint acceptance by the Contractor and

Subcontractor of the suitability of surfaces and conditions within any given area.

II. Applying Coatings:

a. Multiple coats of the same material must be of a different tint to ensure that each coat provides complete coverage.

b. Apply coatings to clean, dust free, suitably dry surfaces in dry atmospheric conditions and after any previous coats have cured adequately.

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c. Apply coatings evenly to give a smooth finish of uniform thickness and colour, free from brush marks, nibs, sags, runs and other defects.

d. Keep all surfaces clean and free from dust during coating and drying. Adequately protect completed work from damage.

III. Film Thickness:

a. Check the thickness of each coat during application using a wet film thickness wheel

or comb gauge in accordance with BS EN ISO 2808

b. After each coat has dried measure the total accumulated dry film thickness using a magnetic or electromagnetic meter, checked against standard shims and recalibrated regularly against a smooth steel reference plate, the number and position of measurements to be as directed by the Engineer. If requested carry out the testing in the presence of the Engineer. Submit written reports to the Engineer.

c. Over any square metre of coating the average accumulated dry film thickness must equal or exceed the specified thickness, with no reading less than 75% of the specified thickness.

d. If at any stage the accumulated dry film thickness is deficient, the Engineer may require application of additional coat(s) at no extra cost.

e. The Dry Film Thickness (DFT) of the top coat must be sufficient to give an even, solid, opaque appearance.

f. Where a minimum DFT has been specified any areas found to be below the specified figure will be made good at no extra cost.

IV. Stripe Coat

a. Stripe coating of any flanges or edges, external angles, nuts, bolt heads, rough weld

seams, and any areas that are difficult to access is to be carried out by brush prior to the spray application of the specified primer.

V. Colour of Top Coat

a. To be selected by the Engineer (unless already specified). Colour of preceding coat to

be as recommended by the paint manufacturer to suit the top coat colour.

VI. Junctions with Concrete:

a. Where exposed steelwork is partially embedded or encased in concrete, apply two coats of an approved bituminous coating locally to the steel/concrete junction as instructed by the Engineer.

2.4 GROUT A. Grouts used for bedding steel bases or bearing plates on concrete foundations shall be agreed with the

Engineer. A high strength, non shrink or expanding type of proprietary cementitious compound for grouting is required.

B. The Contractor shall design the mix for the grout such that the grout has sufficient bearing capacity for the loads to be transferred through it.

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C. Foundations are to be pre-soaked with water the day prior to grouting of a base plate.

D. The Contractor is to ensure that prior to pouring the grout the areas is free from water and debris such as oil, grease or adherent material. If the concrete surface is defective, it must be cut back to a sound base. Bolt holes are to be blown clean of dirt.

E. The Contractor must demonstrate that there are no gaps, and that no cracks develop once the grout has been poured.

2.5 FABRICATION A. Structural Steelwork

I. Inform the Engineer when fabrication is due to start 2 weeks before commencement.

II. Before fabricating, ensure that surface condition of steel which is to be coated complies

with requirements for cleaning given elsewhere in this Specification.

III. Ensure that fabrication processes do not cause changes in properties of materials resulting in non-compliance with specified requirements.

IV. Trial assemblies shall be carried out in general and for any large truss elements in particular.

V. The size of the assemblages shall be determined by the Contractor to the approval of the Engineer and shall be sufficient to ensure that fit up and erection tolerances can be achieved on site.

VI. Any material identification marks which have been hard stamped into the material shall be cut off in the course of fabrication.

VII. All measurement shall be made by a steel tape related to a standard tape which has been certified to be correct at 20C. The tape and the steel to be measured shall be at the same temperature and proper precautions shall be taken to tension the tape correctly.

VIII. All plates, bars and sections shall be flat, straight and free from twist within the tolerances

specified in the relevant British Standard and NSSS, unless more stringent tolerances are specified on the Engineer's Contract Drawings (e.g. structural movements for cladding and movement joints, floor vibration and building tolerances). Any flattening or straightening required to achieve the required tolerances or to satisfy fit-up requirements shall be carried out before any other work is done on that item. The method adopted for such work shall be such as not to deface or weaken the material.

B. Thermal Cutting and Machining

I. Steel may be sawn, sheared, cropped or machine flame cut. Where it is impractical to use

machine flame cutting, the use of hand flame cutting shall be subject to the approval of the Engineer, who may require dressing or other treatment of the cut edges, depending on the details of the joint or member. All flame cutting shall be subject to agreement.

II. Where notches are necessary they shall have smooth arced internal corners, produced by drilling holes not less than 20mm diameter before cutting the rest of the notch or by carefully controlled flame cutting.

III. All burrs left by sawing, cropping or shearing shall be removed before fabrication or assembly. All sharp arises shall be removed by light grinding.

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IV. The Contractor shall inform the Engineer of members on which he will be using shearing

or flame cutting and in cases where steel so cut is specified as being subject to dynamic or fatigue loading or liable to brittle fracture, the sheared or flame cut edges shall be machined to a depth to be agreed by the Engineer.

V. The ends of compression members at splices, caps or bases, dependent on contact for the transmission of compressive stress, shall be prepared so that the butting faces are in contact over at least 50% of the bearing area except for small clearances not exceeding 0.25mm. Over the remaining area the gap shall not exceed 0.50mm. Base and cap plates and other bearing surfaces shall also be prepared to the same standard.

VI. Members shall be adequately supported in both the vertical and horizontal planes during cutting or machining to ensure that the prepared ends are square to the axis of the member.

VII. All plates 25 mm thick and over which are to be connected using high strength friction grip (HSFG) or fully tensioned fasteners shall be checked for bowing or 'ripples'; if these defects are present they shall be eliminated before dispatch to site.

VIII. In HSFG or fully tensioned connections all surfaces which have been machined shall be grit blasted in such a way as to provide a slip factor of not less than 0.45.

IX. Fitted Plates and Stiffeners: The ends of fitted plates and stiffeners shall be accurately sawn or sheared and ground to fit tightly between the flanges or parts to be stiffened. The maximum gap shall not exceed 0.25 mm.

X. Smithed Work: All forging shall be performed in such a manner as not to impair the strength of the metal. The metal shall not be worked after it has fallen to a 'blue heat'.

XI. Base plates Provide 25 mm diameter holes in all base plates more than 1 m2 in area to allow the escape of air when grouting after erection of columns.

C. BOLT HOLES:

I. Holing shall be in accordance with BS 5950 Part 2 (or BS 4604: Part 1 in the case of holes

for friction grip bolts). All 'burrs' and 'rags' shall be removed.

II. Slotted holes shall either be punched in one operation or else formed by punching or drilling two round holes and completed by high quality flame cutting and dressing, to ensure that the bolt can travel the full length of the slot freely.

III. Circular holes for bolts shall not be flame cut.

IV. Cut, drill, mechanically thermal cut, or punch standard bolt holes perpendicular to metal surfaces.

D. Finishing: Accurately finish ends of columns and other members transmitting bearing loads.

E. SHEAR CONNECTORS: Prepare steel surfaces as recommended by manufacturer of shear connectors.

Use automatic end welding of headed-stud shear connectors according to the relevant British Standard and manufacturer's written instructions.

F. STEEL WALL-OPENING FRAMING: Select true and straight members for fabricating steel wall-opening framing to be attached to structural steel. Straighten as required to provide uniform, square, and true members in completed wall framing.

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G. HOLES: Provide holes required for securing other work to structural steel and for other work to pass

through steel framing members.

I. Cut, drill, or punch holes perpendicular to steel surfaces. Do not thermally cut bolt holes or enlarge holes by burning.

II. Base plate Holes: Cut, drill, mechanically thermal cut, or punch holes perpendicular to steel surfaces.

III. Weld threaded nuts to framing and other specialty items indicated to receive other work. 2.6 SHOP CONNECTIONS A. Bolted Connections

I. Bolting up with Close Tolerance Bolts: Holes for close tolerance bolts shall be drilled and

reamed. Where the holes are not drilled through all thicknesses in one operation, the parts to be joined together shall be accurately lined up with parallel drifts of a diameter not greater than the nominal size of the hole and not smaller than 0.15 mm less than the nominal diameter and the holes then reamed. A close tolerance bolt shall be fitted in each hole reamed and tightened before the next hole is reamed. All bolts shall be re-tightened after the last bolt has been fitted.

II. Bolted Movement Connections: Slotted holes for movement connections shall be provided with shouldered bolts, spring washers and flat washers.

III. Correcting hole alignments: Drifting to align holes shall not enlarge the holes or distort the metal. Holes which cannot be aligned without distortion shall be a cause for rejection unless enlargement by reaming is specifically approved by the Engineer.

IV. Provision of washers:

a. Washers shall be provided at slotted holes and elsewhere as specified. With metal sprayed steelwork a washer shall always be provided under both head and nut.

b. Square taper washers shall be provided for all bolts where the bolt head or nut is

bearing on a surface at an angle to the bolt axis greater than 93 or less than 87.

V. Bolting Metal Sprayed or Galvanised Steelwork: Ordinary bolted connections on metal sprayed or galvanised steelwork shall be made using spun galvanised or sheradised bolts, nuts and washers except where connecting coated steelwork to black steelwork.

B. Weld Connections: Welding shall comply with the requirements and recommendations of BS 5135 (and associated revised equivalent standards) except as otherwise directed in this Specification and on the Contract Drawings.

I. The Contractor shall determine the welding procedure details to meet the requirements of this Specification, including the requirements of Inspection and Quality Control.

II. Unless otherwise specified, T-butt welds shall be reinforced by equal-leg fillet welds of leg length equal to a quarter of the thickness of the thinner plate joined, but not less than 3mm nor greater than 10mm.

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III. Where the steelwork is to be blasted and metal sprayed or galvanised after fabrication, cleats and other solid attachments welded to the member shall be welded all round to seal the unprotected surface.

IV. Welding procedure details for steels not complying with BS EN 10025, BS EN 10155, BS EN 10113, or BS EN 10210 - Grades S275 or S355 shall be agreed with the Engineer before fabrication is started, on the basis of weld procedure tests in accordance with BS EN 288.

V. Except as otherwise specified, the fit up of elements before welding shall conform to the recommendations for manual welding given in the note in clause 11.1 of BS 5135.

VI. The root edges or root faces of butt welds shall not be out of alignment by more than 15 percent of the thickness of the thinner material but not greater than 3mm.

VII. The Contractor shall demonstrate to the satisfaction of the Engineer that the proposed weld procedure details are derived from procedures which have already been approved. Where weld procedure tests are required to be performed to demonstrate this, the tests shall be in accordance with BS EN 288.

VIII. All welders shall be suitably qualified and experienced for the work on which they are employed and shall have satisfied the relevant requirements of BS EN 287 or BS 4872: Part 1 as appropriate. The Contractor shall keep records identifying the welder for each welded joint. Copies of welders' qualifications shall be provided by the Contractor when requested by the Engineer.

IX. Welded attachments for fabrication or erection purposes shall be subject to the Engineer's approval and shall be clearly shown on the Shop Drawings.

X. Unless otherwise specified, all welds shall not be undersized. Butt welds shall have a uniform convexity up to a maximum of (weld size/5) or 3mm whichever is lesser. Concave fillet weld shall have a throat thickness not less than 0.7 times the specified leg length. Convex fillet welds shall have a throat thickness not more than 0.9 times the actual leg length. All welds shall have a smooth surface.

XI. In addition to the above requirements, all welds on steelwork which is not clad shall be ground smooth.

XII. Site Welding: Site welding is not permitted unless shown on the Contract Drawings or otherwise approved. When permitted, the Contractor shall ensure suitable, safe working conditions. Do not weld when surfaces are wet or when the ambient temperature is below 0C. A method statement is required for prior review detailing all procedures for management and control of site welding procedures. All site welding to be subject to 100% testing. All site welding shall be 100% tested using Visual Testing (VT), Magnetic Particle Inspection (MT) and digital Ultrasonic Inspection (UT). Engineer reserves right to ask for further Radiographic Inspection (RT) of the thick joints.

C. Marking

I. Each piece of steel shall be uniquely identified throughout the fabrication process.

II. Each piece of steelwork shall be distinctly marked before dispatch in accordance with the

marking drawing prepared by the Steelwork Contractor. Where applicable it shall also be given other marks and symbols to assist erection at site, by showing from which works it has come and to which crane or area it is to be delivered.

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III. The location of marks on members shall be consistent and shall be such that the marks are clearly visible both before and after erection.

IV. Painted marks shall be applied using a paint that is compatible both in colour and chemically with the final site anti-corrosion treatment.

V. The method of marking steelwork which is to be supplied to site fully painted shall, unless

specified otherwise, be as agreed with the Engineer.

VI. The painting of the Contractor's name or other advertising matter on steelwork is not permitted. Any such advertisement must be in the form of labels which are to be removed after the steel arrives on site.

VII. The marking of Safe Working Load on runway beams shall comply with BS 2853.

VIII. Where high strength bolts and threaded rods are used, additional marking must be visible which will identify the strength of these. The manufacturers standard markings will suffice provided that they can be easily read on site before the bolts are fixed.

IX. Marking of steel which is to be blast cleaned, pickled, metal sprayed or galvanised to be by an approved method which cannot be obliterated.

X. Hard stamping must not be used except where specified on the drawings by the Engineer.

2.7 SHOP PRIMING A. Shop prime steel surfaces except the following:

I. Surfaces embedded in concrete or mortar. Extend priming of partially embedded

members to a depth of 50 mm.

II. Surfaces to be field welded.

III. Surfaces to be high-strength bolted with slip-critical connections.

IV. Surfaces to receive sprayed fire-resistive materials (applied fireproofing).

V. Galvanized surfaces.

B. Surface Preparation as Per BS:

I. Steel surfaces shall not be more heavily pitted or rusted than Grade C of BS 7079 Part A1. Any major surface defects shall be reported to the Engineer and his instructions followed.

II. Any minor surface defects such as surface laminations, blow holes and crevices exposed by blast cleaning shall, subject to the approval of the Engineer, be made good as specified in BS EN 10025, BS EN 10113, BS EN 10155, BS 7613, BS EN 10210 or BS 7668 as appropriate.

III. Surfaces which become inaccessible after fabrication or assembly, such as the inside of structural hollow sections and other box sections, shall be sealed off from the outside atmosphere by continuous welds unless specified otherwise.

IV. Hollow members which are to be galvanised shall have vent holes. These shall be large enough to ensure internal galvanising or if so specified shall be sealed after the member has been galvanised.

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V. Contact surfaces, other than those where HSFG fasteners are to be used, shall be treated

as required by Section 05 80 00 Corrosion Protection for Structural Steelwork. The Contractor shall check the faying surfaces in steel 25 mm thick or more for deformities such as bowing, twist or rippling which may reduce slip factor to below design limit. The Contractor shall agree remedial measures with the Engineer.

VI. Where specified on the Contract Drawings machined surfaces shall receive an approved coat of travel varnish within four hours of machining.

C. Priming: Immediately after surface preparation, apply primer according to manufacturer's written

instructions. Use priming methods that result in full coverage of joints, corners, edges, and exposed surfaces.

I. Stripe paint corners, crevices, bolts, welds, and sharp edges.

II. Apply two coats of shop paint to surfaces that are inaccessible after assembly or erection.

Change color of second coat to distinguish it from first. D. Painting: Prepare steel and apply a one-coat, non-asphaltic primer complying with SSPC-PS Guide

7.00, "Painting System Guide 7.00: Guide for Selecting One-Coat Shop Painting Systems," to provide a dry film thickness of not less than 0.038 mm.

2.8 GALVANIZING A. Hot-Dip Galvanized Finish: Apply zinc coating according to Section 099113 Part A

B. Fill vent and drain holes that will be exposed in the finished Work unless they will function as weep holes,

by plugging with zinc solder and filing off smooth.

2.9 SOURCE QUALITY CONTROL A. Comply with pertinent provisions of the relevant British Standards.

B. Constituent materials shall be obtained from suppliers operating quality systems in accordance with

either ISO 9001 or an in-house system approved by Engineer.

C. If it is found necessary to substitute alternative sections for any of the steel sections specified then the written approval of the Engineer for the substitution and for the amendments to the Contract Drawing showing the substitution shall be obtained before fabrication is commenced.

D. Lamination Testing

I. Except in the case of special plate with through thickness properties guaranteed by the manufacturer, all plates and sections 25mm or over in thickness shall be ultrasonically tested for laminations, and shall meet the acceptance criteria of level B6 to BS 5996.

II. Other plates may be specified to be ultrasonically tested for laminations. Unless otherwise specified they shall meet the requirements of level B6 to BS 5996.

III. Welded joints that cause high tensile through thickness strains to occur (as discussed in Appendix G of BS 5135), shall be fabricated from steel that meets the quality level Z35 of BS EN 10164.

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IV. For all steel plates and sections which will be subject to through-thickness stresses, the Contractor shall carry out non-destructive testing on the steel to ensure that the affected zones are free from laminations and inclusions. Table 5, 18 and 19 of BS 5135 shall be used to determine acceptance levels for steel products.

E. Welding shall meet the requirements stated in subsection Materials - Welding and shall be subject to the

inspection and testing requirements stated in subsection Inspection and Quality Control.

F. Requirements for a welding plan.

Before commencement of the work, the Fabricator shall forward a welding plan for the work to Engineer for review and comments. The welding plan shall adhere to all requirements in BS EN 1090-2 section 7.2.2.

3 EXECUTION 3.1 EXAMINATION A. Verify, with steel Erector present, elevations of concrete- and masonry-bearing surfaces and locations of

anchor rods, bearing plates, and other embedments for compliance with requirements. B. Prepare a certified survey of bearing surfaces, anchor rods, bearing plates, and other embedments

showing dimensions, locations, angles, and elevations.

C. Proceed with installation only after unsatisfactory conditions have been corrected.

3.2 PREPARATION A. Provide temporary shores, guys, braces, and other supports during erection to keep structural steel

secure, plumb, and in alignment against temporary construction loads and loads equal in intensity to design loads. Remove temporary supports when permanent structural steel, connections, and bracing are in place unless otherwise indicated.

B. Do not remove temporary shoring supporting composite deck construction until cast-in-place concrete has attained its design compressive strength.

3.3 ERECTION A. Method of Erection

I. The Contractor shall submit a detailed Method Statement to the Engineer for approval

prior to erection. When necessary to amplify the information given in his Method Statement, the Contractor shall prepare Erection Drawings for approval by the Engineer.

II. Erection of the steelwork shall be carried out in a safe manner and the work shall be arranged in such a manner as to facilitate phased hand over of the steelwork for subsequent operations.

B. The Contractor shall supply adequate plant, tools, service bolts, drifts, bolt tightening devices and other

equipment to ensure that the steelwork is correctly erected in accordance with the programme.

C. Transport, Storage, Handling and Attachments

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I. Care shall be taken when transporting, storing, handling or erecting all material to ensure

that no part is damaged. Damage to any part of the structure either before or during erection shall immediately be brought to the notice of the Engineer. Damaged material shall be rectified or replaced. No part that has been damaged shall be assembled into the structure without the written approval of the Engineer.

II. Steelwork to be stored shall not be placed directly on the ground. It shall be stored in such a manner as to avoid water retention.

III. Particular care shall be taken when transporting, handling or storing parts which have been metal sprayed, galvanised or painted. If the coating is damaged it shall be restored to comply with the relevant requirements of the Specification for Corrosion Protection for Steelwork 05 80 00.

IV. Lifting points shall be suitably wrapped and protected and steel slings shall not be allowed to come into direct contact with coated steelwork.

V. Welded attachments shall not be employed unless they are clearly shown on the Shop Drawings.

D. Foundations

I. All the necessary anchorage materials which are to be built into the foundations shall be

supplied to site in time to meet the agreed programme.

II. Immediately after the foundations are available the Contractor shall satisfy himself that the foundations have been correctly formed and that the holding down bolts have been accurately set and have the full amount of play shown on the Contract Drawings and shall inform the Engineer accordingly, in writing.

E. Temperature Effect

I. Due account shall be taken for the effects of temperature on the structure and on tapes

and instruments when measurements are made for setting out, during inspection and for subsequent dimensional checks. The reference temperature shall be 20 deg C.

II. In setting out and erecting continuous structures proper adjustments shall be made as approved by the Engineer to counteract dimensional discrepancies owing to temperature variations.

III. Where stanchion bases are to be cast into pockets formed in concrete foundations, any horizontal steel members which tie the stanchions together shall be fixed first and the stanchions shall then be lined, leveled, plumbed and concreted in and the concrete in the pockets allowed to harden before fixing the rest of the steelwork to them.

IV. Except where specified otherwise, sliding joints shall be treated with molybdenum disulphide grease before erection.

V. The Contractor shall limit the temperature effects during erection by adequately controlling the temperature of the element using thermal insulation or an alternative system approved by the Engineer. He shall demonstrate that the change in temperature of any element or elements shall not cause undue effects on the structure

F. Lining and Leveling

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I. The permanent welding or bolting up of connections shall not be carried out until a sufficient portion of the structure has been erected and temporarily connected up, to ensure that there will be no straining of members during the erection and lining up of the remainder of the structure.

II. Adequate temporary bracing shall be provided and left in position until such time as the building is sufficiently far advanced for such bracing to be no longer required.

III. Packs for leveling up stanchions shall be shown on the drawings submitted for the Engineer's approval. At least three sets of packs shall be used for each stanchion. The number of packs provided shall be 25% in excess of the theoretical requirement.

IV. Packs shall not be larger than is necessary for their purpose, they shall be sawn and not sheared or flame cut. Packs shall not protrude unduly from the stanchion base; they shall be grouted in and the grout shall totally enclose them.

G. Grouting up of Structures

I. The Engineer shall be informed when stanchions or other members have been lined,

levelled and plumbed and no grouting or concreting-in shall be done until the Engineer has approved the alignment and plumbing.

II. Following such approval the Contractor shall immediately grout the base plates and concrete in the stanchions or other members.

H. Composite Columns

I. Welding to Concrete Filled Columns: Primary load bearing structural components shall be

welded to the column before commencing to fill with concrete. Subject to the approval of the Engineer, the welding of relatively small lugs and fittings after filling may be allowed. N/A

II. Column Welded Splices: To allow welding to take place, the concrete filling shall be stopped at a level approximately 250mm below the top of the column. The next column length can then be spliced into place using a full penetration butt weld with a backing ring. Following this, concrete filling can be resumed.

III. Bolted Flange Joints: When a flanged connection is used, the flange shall be welded to the column before filling. When flanges are used at both ends of a column length at least one flange shall have to incorporate an aperture for filling. In order to ensure complete filling under this flange, the maximum size of any lip shall not exceed 15mm.

IV. Preparation for Concrete Placing

a. Surfaces to receive concrete shall conform to Specification for Corrosion Protection for Steelwork: Internal - Concrete encased.

b. All loose material and debris shall be removed from the bottom of the column. Any

free water which may have collected at the bottom shall also be removed.

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Works Tend