toyo engineering india limited -...

ENGINEERING SPECIFICATION OR

STRUCTURAL STEEL WORK

FOR

NITROGEN UNIT

FOR

HINDUSTAN PETROLEUM CORPORATION LTD.

VISAKH REFINERY

DHT PROJECT

JOB NO. : 6261

DOCUMENT NO. : A-6261-A-322

TOTAL NO. OF PAGES: 43 (INCLUDING THIS PAGE)

0

13-04-2009 FOR BID ENQUIRY RKB SVP RCN

REV.

DATE

DESCRIPTION

MADE BY

CHECKED

APPROVED

TOYO ENGINEERING INDIA LIMITED MUMBAI INDIA

MUMBAI

INDIA

STANDARD ENGG SPECIFICATION


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A-322

TOYO ENGINEERING INDIA LTD.

ISSUED: 13-04-2009 CIVIL DESIGN DEPARTMENT PAGE 2 OF 43

CONTENTS

PARA

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DESCRIPTION PAGE

NO.

1.0 SCOPE 5

2.0 APPLICABLE CODES 5

3.0 PRIORITY OF REQUIREMENT 8

4.0 MATERIALS 9

4.1 General 9 4.2 Structural Steel 9 4.3 Welding Consumables 9 4.4 Bolts, Nuts and Washers 9 4.5 Receipt and storing of materials 10 4.6 Tests after delivery 10 4.7 Rejection 10

5.0 FABRICATION DRAWINGS 10

6.0 FABRICATION 13

6.1 General 13 6.2 Fabrication Procedure 14

7.0 WELDING 17

7.1 General 17 7.2 Preparation of members for welding 18 7.3 Welding Processes 19 7.4 Types of Welding 19 7.5 Welding Plant 20 7.6 Approval and Testing of Welders 21 7.7 Approval and Testing of Welding Procedures 21 7.8 Sequence of Welding 21 7.9 Welding Procedure 22 7.10 Precautions 23 7.11 Operation and Workmanship 23 7.12 Inspection and Testing of Welds 24 7.13 Mechanical Tests 25 7.14 Magnetic Particle / Dye Penetration / Ultrasonic

Examination 25

7.15 Radiographic Examination 26

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PARA

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DESCRIPTION PAGE

NO.

7.16 Repair of Faulty Welds 26 7.17 Splicing 27

8.0 BOLTING 27

8.1 General 27 8.2 Preparation of members for bolting 28 8.3 Bolting Up 28 8.4 Check Assembly 28

9.0 MISCELLANEOUS FABRICATION ACTIVIITES 28

9.1 Plaining of Ends 28 9.2 Holes for Field Joints 29 9.3 Marking for identification 29 9.4 Shop Test Pre-Assembly 29

10.0 SHOP INSPECTION AND APPROVAL 30

10.1 General 30 10.2 Shop Acceptance 30

11.0 INSPECTION ON SITE 31

12.0 PACKING, TRANSPORATION, DELIVERY 32

13.0 STORAGE AND PREPARATION

PRIOR TO ERECTION

32

14.0 ERECTION 33

14.1 General 33 14.2 Hoisting and Erection 34

15.0 ERECTION TOLERANCES 35

16.0 ANCHOR BOLTS 37

16.1 Material 37 16.2 Fabrication 37 16.3 Placement 38 16.4 Tolerances 38 16.5 Protection 38

17.0 MS INSERTS / CORNER ANGLES 38

17.1 Material 38 17.2 Fabrication 38 17.3 Placement 38

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PARA

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DESCRIPTION PAGE

NO.

18.0 CHEQUERED PLATES 38

18.1 Material 38 18.2 Fabrication 39 18.3 Erection / Fixing 39

19.0 GRATING 39

19.1 Categories 39 19.2 Material 39 19.3 Fabrication 39 19.4 Erection / Fixing 40

20.0 HANDRAILING 40

20.1 Material 40 20.2 Fabrication 40 20.3 Erection / Fixing 40

21.0 STAIRCASE AND LADDERS 41

22.0 MILD STEEL RUNGS 41

22.1 Materials 41 22.2 Fabrication 41 22.3 Fixing 41

23.0 EXPANSION FASTENERS 41

23.1 Material 41 23.2 Classification 41 23.3 Limitations 42 23.4 Selection 42 23.5 Testing 42 23.6 Installation 42 23.7 Protection 43

24.0 GROUTING 43

25.0 PAINTING 43

26.0 MEASUREMENTS 43

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1.0 SCOPE

This specification covers the requirements for material, fabrication, assembly, testing, transportation, erection of all types of structure steelworks consisting of columns, beams, trusses, lattice girders, pipe racks, pipe supports, trestles, masts, galleries, monorails, gantry girders, platforms, stairs, ladders, handrails, purlins, side runners, equipment supporting structures, guide structure (for stacks, towers/columns), etc for general construction work. The scope of work shall include but not limited to: (a) Preparation of detailed shop fabrication drawings based on design drawings. (b) Design of connections (if required) and preparation of complete bill of materials. (c) Preparation of structural erection/assembly drawings to suitable approved

scale showing all dimensions, size of members, location, thickness of structural parts, gussets, marking, number, diameter, length and bolt locations, centre of gravity and back mark lines, slopes, other accessories, erection marking etc. complete.

(d) Straightening of raw steel, if necessary prior to fabrication. (e) Supply of bolts, nuts, lock nuts, flat/spring washers, welding electrodes.

2.0 APPLICABLE CODES

Note: - Wherever reference is made to IS Codes, on any page of this Technical Specification (including annexures), applicable year of publication of IS Code is as stated below.

The Indian Standard Codes applicable to this section shall include but not limited to the following:

IS 800 - 1984 : Code of practice for general construction in steel.

IS 806 - 1968 : Code of practice for use of Steel tubes in general building construction.

IS 808 -1989

: Dimensions for hot rolled steel beam, column, channel and angle sections.

IS 813 - 1986 : Scheme of Symbols for welding.

IS 814 - 2004 : Covered electrodes for manual metal arc welding of

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Carbon and Carbon Manganese Steel.

IS 816 - 1969 : Code of Practice for use of metal arc welding for general construction in mild steel.

IS 817 - 1966 : Code of Practice for training and testing of metal arc welders.

IS 818 - 1968 : Code of Practice for safety and health requirements in electric and gas welding and cutting operations.

IS 819 - 1957 : Code of Practice for resistance spot welding for light assemblies in mild steel.

IS 822 - 1970 : Code of Practice for Inspection of Welds.

IS 919 (Part 1) and (Part 2) 1993

: ISO System of limits and fits.

IS 1024 - 1999 : Code of Practice for use of welding in Bridges and Structures subject to dynamic loading.

IS 1149 1982 : High tensile steel rivet bars for structural purpose.

IS 1161 1998 : Steel tubes for structural purpose.

IS 1182 - 1983 : Recommended practice for radiographic examination of fusion welded butt joint in steel plates.

IS 1239 (Part 1) - 2004

: Mild steel tubes, tubular and other wrought steel fittings Part 1 Mild steel tubes.

IS 1239 (Part 2) - 1992

: Mild steel tubes, tubular and other wrought steel pipe fittings. Part 2 Mild steel tubular and other wrought steel pipe fittings.

IS 1261 - 1959 : Code of Practice for Seam Welding in Mild Steel.

IS 1323 - 1982 : Code of Practice for Oxyacetylene welding for Structural Work in Mild Steel.

IS 1363 (Part 1) to (Part 2) - 2002.

: Hexagon head bolts, screws and nuts of product grade C (Size range M5 to M64).

IS 1364 (Part 1) to : Hexagon head bolts, screws and nuts of product

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(Part 5) - 2002 grades A & B (Size range M1.6 to M64).

IS 1367 (Part 1) to (Part 20)

: Technical supply conditions for Threaded Steel Fasteners.

IS 1608 - 1995 : Mechanical testing of metals tensile testing.

IS 1852 - 1985 : Rolling and cutting tolerances for hot rolled steel products.

IS 2016 - 1967 : Plain Washers.

IS 2062 - 1999 : Steel for general structural purposes.

IS 2595 - 1978 : Code of practice for radiographic testing.

IS 2629 - 1985 : Recommended Practice for Hot Dip Galvanizing on Iron and Steel.

IS 2633 - 1986 : Methods of Testing Uniformity of coating of Zinc coated articles.

IS 3443 - 1980 : Crane rail sections.

IS 3460 - 1991 : Knurled nuts.

IS 3502 - 1994 : Steel chequered plates.

IS 3613 - 1974 : Acceptance tests for wire flux combination for submerged arc welding.

IS 3640 - 1982 : Hexagon fit bolts.

IS 3658 - 1999 : Code of practice for liquid penetrant flaw detection.

IS 3757 - 1985 : High strength structural bolts.

IS 4000 - 1992 : High strength bolts in steel structures Code of Practice.

IS 4218 - (Part 1 to Part 6)

: ISO Metric Screw Threads.

IS 4353 - 1995 : Submerged arc welding of mild steel and low alloy steels Recommendations.

IS 5334 - 2003 : Code of practice for magnetic particle flaw detection of welds.

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IS 5369 - 1975 : General requirements for plain washers and lock washers.

IS 5370 - 1969 : Plain washers with outside diameter 3 x inside diameter.

IS 5372 - 1975 : Taper washers for channels (ISMC).

IS 5374 - 1975 : Taper washers for I-Beams (ISMB).

IS 6610 - 1972 : Heavy washers for steel structures.

IS 6623 - 2004 : High strength structural nuts.

IS 6639 - 1972 : Hexagonal bolts for steel structures.

IS 6649 - 1985 : Hardened and tempered washers for high strength Structural bolts and nuts.

IS 6745 - 1972 : Methods of determination of mass of zinc coating on zinc coated iron and steel articles.

IS 7215 - 1974 : Tolerances for fabrication of steel structures.

IS 7310 (Part 1) - 1974

: Approval tests for welders working to approved welding procedures Part 1 Fusion welding of steel.

IS 7318 (Part 1) & (Part 2) - 1974

: Approval tests for welders when welding procedure approval is not required.

IS 8172 - 1976 : Vertical steel ladder.

IS 8500 - 1991 : Structural Steel Micro alloyed (medium and high strength quality).

IS 9595 - 1996 : Metal Arc welding of carbon and carbon manganese steels Recommendations.

3.0 PRIORITY OF REQUIREMENT In case of any variation and discrepancy in condition between the special

conditions, this specification and codes, order of priority shall be as under:- (1) Special conditions (2) This specification (3) Codes

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4.0 MATERIALS 4.1 General

All materials shall confirm to the Specifications given below. The use of equivalent or alternative materials shall be permitted only in very special case and for all such cases prior written approval of the Engineer-In-Charge shall be obtained. LSTK CONTRACTOR shall replace any defective material noticed at any stage of work at his own expenses. Materials for which Test Certificate are not available or for which test results do not conform with relevant standard specifications, shall not be used. LSTK CONTRACTOR shall be required to produce manufacturers quality certificate for the material. In case of absence of such certificates LSTK CONTRACTOR shall conduct all appropriate tests as directed by Engineer-In-Charge at no extra cost, in approved laboratories. Tolerances for hot rolled Structural Steel sections for rolling and cutting shall be as per IS 1852.

4.2 Structural Steel

The Structural Steel shall conform to IS 2062 unless specified otherwise.

4.3 Welding Consumables

Covered electrodes for metal arc welding of structural steel shall conform to IS 814 and tested as per IS 1608. Bare wire electrodes for submerged arc welding of structural steel shall conform to IS 7280. The combination of wire and flux shall comply with IS 3613. Filler rods and wires for gas welding shall conform to IS 1278. Filler rods and bare electrodes for gas shielded arc welding of structural steel shall conform to IS 6419.

4.4 Bolts, nuts and washers

Bolts and nuts (including lock nuts) shall conform to IS 1363, IS 1364, IS 1367, IS 3460, IS 3757, IS 6623 and IS 6639 as applicable. Washers shall conform to IS 5369, IS 5370, IS 5372, IS 5374, IS 6610 and IS 6649 as applicable. Bolts, nuts and washers shall be tested as per IS 1608.

4.5 Receipt and Storing of Materials

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4.5.1 All sections shall be checked, sorted out and arranged by grades in the stores

as per the instructions given by the Engineer-In-Charge. 4.5.2 All sections shall be free from surface defects such as pitting, cracks,

laminations, twists etc. The use of defective sections shall not be permitted and all such rejected material shall be immediately removed from the store / site.

4.5.3 Each section shall be marked for identification and each lot shall be

accompanied by manufacturers quality certificate, chemical analysis and mechanical characteristics.

4.5.4 Welding wires and electrodes (packed in their original cartons) shall be stored

separately by quality and lots inside a dry and enclosed room in compliance with IS 9595 and as per the instructions given by the Engineer-In-Charge. Electrodes shall be kept perfectly dry to ensure satisfactory operation and weld metal soundness.

4.5.5 Each lot of electrodes, bolts, nuts etc., shall be accompanied by manufacturers

quality / test certificates. 4.5.6 All bolts (including nuts and washers) shall be checked, sorted out and arranged

diameter wise by grade and quality in the store. 4.6 Tests after delivery 4.6.1 The LSTK CONTRACTOR shall be required to produce manufacturers quality

certificates for all the materials supplied by him. In case, quality certificates are not available or incomplete or when material quality differs from standard specifications, such materials shall not be used in the construction. However, the LSTK CONTRACTOR shall get all appropriate tests conducted in approved test houses for such materials as directed by the Engineer-In-Charge, at no extra cost, and submit the same to Engineer-In-Charge for his approval. The Engineer-In-Charge may approve the use of such materials entirely at his discretion.

4.6.2 Materials for which test results do not conform to relevant standard

specifications / IS Codes shall not be used and shall be removed from site. 4.7 Rejection

The Engineer-In-Charge may reject at his discretion any material, not withstanding the manufacturers certificate or failing to meet the requirements of relevant IS Codes for testing of materials. He may similarly reject any material, which has deteriorated, corroded, etc, due to improper storage, handling or transport. Defective materials shall not be used and removed from the site by the LSTK CONTRACTOR at no extra cost.

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5.0 FABRICATION DRAWINGS 5.1 Fabrication and erection drawings shall be prepared in metric units, by the LSTK

CONTRACTOR on the basis of Approved for Construction (AFC) design drawing issued to the LSTK CONTRACTOR. These drawings shall be prepared by LSTK CONTRACTOR or by an agency approved by TEIL.

5.2 Engineer-In-Charge shall furnish foundation drawings, if such drawings are

considered necessary for preparation of fabrication drawings. These drawings shall show details of foundation anchor bolts.

5.3 LSTK CONTRACTOR shall be responsible for the correctness of the fabrication drawings. LSTK CONTRACTOR shall not start fabrication prior to approval of fabrication drawings by Engineer-In-Charge

5.4 Review of fabrication drawings by Engineer-In-Charge shall in no way relieve the

LSTK CONTRACTOR of his responsibility of correctness of Engineering and execution of the work.

LSTK CONTRACTOR shall be required to modify / rectify the structure at any stage of the work in case Engineer-In-Charge brings to his attention any mistake / omission in the fabrication drawings and the fabrication based on these drawings.

All such modifications / rectifications shall be made by the LSTK CONTRACTOR at no extra cost to OWNER / TEIL.

5.5 Fabrication and erection drawings shall be thoroughly checked, stamped

Approved for Construction and signed by the LSTK CONTRACTORs authorized representative, to ensure accuracy and correctness of the drawings. Unchecked and unsigned drawings shall be rejected and treated as non-submission.

5.6 Review of fabrication drawings by Engineer-In-Charge shall be limited to the layout, arrangement, sizes of members and connection between members. All other details shown on the fabrication drawings shall be the responsibility of the LSTK CONTRACTOR.

5.7 The LSTK CONTRACTOR shall ensure accuracy of the following, (but not limited to) and shall be solely responsible for the same:

(a) Provision for erection and erection clearances. (b) Marking of members.

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(c) Cut length of members. (d) Matching of joint and holes (e) Provision kept in the members for other interconnected members. (f) Bill of materials.

5.8 Fabrication drawings drawn to a proper scale and large enough to convey the information clearly and adequately shall include the following but not limited to:

- Reference to design drawing number (along with revision number), based on which fabrication drawing has been prepared. - Structural layout, elevation and sections. These shall contain distinct

erection marking of all members. - Framing plans member sizes, orientation and elevations. - Layout, detailing of rain water pipes and gutters showing all necessary

levels and connections wherever required. - Detailing of shop/field joints, connections, splices, for required strength

and erection. - Location, type, size and dimensions of welds and bolts. - Shapes and sizes of edge preparation for welding. - Details of shop and field joints / welds. - Bill of materials. - Quality of structural steel, plates, welding electrodes, bolts, nuts, washers

etc to be used. - Erection assemblies identifying all transportable parts and sub-

assemblies with special erection instructions, if required. - Method of erection and special precautions to be taken during erection as

required. 5.9 Connections, splices and other details, where not shown on the design drawings

shall be suitably designed and shown on the fabrication drawings based on Standard Engineering Practice developing full member strength. Design calculation of such connections shall be submitted by LSTK CONTRACTOR and approved by TEIL.

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5.10 Any substitution or change in section shall be allowed only when prior written approval of the Engineer-In-Charge has been obtained. Fabrication drawings shall be updated incorporating all such substitutions / changes by the LSTK CONTRACTOR at no extra cost.

5.11 In case during execution of the work, the Engineer-In-Charge considers any

modifications / substitutions necessary, the LSTK CONTRACTOR shall incorporate the same in the drawings without any extra cost. The LSTK CONTRACTOR shall however be totally responsible for the correctness of the detailed fabrication drawings and execution of the work.

5.12 LSTK CONTRACTOR shall incorporate all the revisions made in the design

drawings, during the course of execution of work in his fabrication drawings, and resubmit the drawings at no extra cost.

5.13 Preparation of Fabrication Drawings shall be in AUTOCAD 13 only. Submission

of Fabrication Drawings in Electronic form shall be as per the instructions of Engineer-In-Charge. Fabrication drawings shall be prepared in A1 size only.

5.14 Unless stated otherwise, submission procedure shall be as stated below.

Initially LSTK CONTRACTOR shall submit 3 copies of all fabrication and erection drawings for review by Engineer-In-Charge. Engineer-In-Charge shall return 1 copy of LSTK CONTRACTOR s drawings marked with his approval and/or comments. LSTK CONTRACTOR shall submit to Engineer-In-Charge with 6 copies of all approved and final drawings for field use and record purposes. LSTK CONTRACTOR shall submit 2 copies of all the As-Built drawings to Engineer-In-Charge for reference and record.

6.0 FABRICATION 6.1 General 6.1.1 Fabrication of structures shall be done strictly as per the Approved for

Construction fabrication drawings and in accordance with IS 800, IS 9595 and other relevant I.S. Codes on the basis of approved Approved for Construction Fabrication Drawings.

6.1.2 Fabrication of structures shall also include fabricating: (a) Built up sections made out of rolled sections and/or plates. (b) Compound sections made out of rolled sections. 6.1.3 Prior to commencement of structural fabrication, undulations in the fabrication

yard, if any, shall be removed and areas leveled by the LSTK CONTRACTOR.

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6.1.4 Any defective material used in the work shall be replaced by the LSTK CONTRACTOR at his own expense. Necessary care and precautions shall be taken, so as not to cause any damage to the structure during any such removal and replacement.

6.1.5 Any faulty fabrication pointed out at any stage of work by the Engineer-In-

Charge, shall be made good or replaced by the LSTK CONTRACTOR at his own cost.

6.1.6 Tolerances for fabrication of steel structures shall be as per IS 7215. 6.2 Fabrication Procedure 6.2.1 Straightening, shaping to form

All materials shall be straight. If necessary, before being worked, these shall be straightened and/or flattened (unless required to be of curvilinear form) and shall be free from twists. It shall be done by a process approved by the Engineer-In-Charge, and in a manner that will not damage the material. All straightening and shaping to form, shall be done by pressure and not by hammering. Any bending or cutting shall be carried out in such a manner, as not to impair the strength of the materials.

6.2.2 Clearances

The erection clearance for members having end cleats or plates shall not be greater than 2mm at each end. The erection clearance at ends of beams without wet cleats and end plates shall not be more than 3mm at each end. Where for practical reasons, greater clearance is necessary, suitably designed seatings, approved by the Engineer-In-Charge shall be provided.

6.2.3 Laying out

Steel structures shall be laid on a leveled platform to full scale and to full size or in parts as shown on drawings or as directed by the Engineer-In-Charge. A steel tape shall be used for measurements. Wooden templates 12mm to 19mm thick or metal sheet templates shall be made to correspond to each member and plate. Bolt holes shall be marked accurately on the templates and drilled. The templates shall be laid on the steel members and holes for bolting marked on them.

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The base of steel columns and the position of anchor bolts shall be carefully set out.

6.2.4 Marking

Prior to cutting, all members shall be properly marked, showing the requisite cut length, width, connection provisions e.g. location and dimensions of holes, welds, cleats, etc. Marking for cutting shall be done judiciously so as to avoid wastage or unnecessary joints, as far as practicable.

Marking shall be done by placing the members on horizontal supports / pads in order to ensure horizontal and straight placement of such members. Marking accuracy shall be limited to +1mm.

6.2.5 Cutting

(a) Members shall be cut mechanically at site by shearing or sawing or by oxyacetylene flame at shop.

(b) Shearing, sawing and gas cutting shall be clean, square, free from any

distortion and burrs. (c) All sharp, rough, broken edges and all edges of joints that are subjected

to tensile or oscillating stresses shall be ground as per instruction of Engineer-In-Charge.

(d) All edges cut by Oxyacetylene process shall be cleaned of impurities and

slag prior to assembling. (e) Cut faces shall not have cracks nor be rough. (f) Electrical metal arc cutting or gauging shall not be allowed. (g) Cutting tolerances shall be as follows (i) For members connected at both ends +1mm. (ii) Elsewhere +3mm.

6.2.6 Making Holes

(a) All holes shall generally be drilled to the required size and at the required position.

(b) In case the thickness of material is less than 16mm, the holes may be

punched prior to assembly, provided the holes are punched 3mm smaller

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in diameter than the required size and reamed after assembly to the required diameter.

(c) When two or more plates or sections are to be bolted together, holes may

be drilled in position, after the members are assembled and the parts firmly held together by clamps. These parts shall be taken apart and all burrs removed, before bolting.

(d) Holes shall have their axis perpendicular to the surface drilled through. (e) The drilling or reaming shall be free from burrs and the holes shall be

clean and accurate. (f) Holes for bolts shall not be formed by gas cutting process. (g) Enlargement of holes, hole plugging by hand drilling, oxyacetylene flame

respectively shall not be allowed. (h) Finished holes shall not be more than 2mm in diameter, larger than the

diameter of the bolt passing through them, unless otherwise specified in the drawings.

(i) Parts to be connected with close tolerance bolts, shall be firmly held

together by tacking bolts or clamps and the holes drilled through all the thickness in one operation and subsequently reamed to size. Holes not drilled through all the thickness in one operation shall be drilled to a smaller size and reamed out after assembly. Where this is not possible, the parts shall be drilled and reamed separately.

(j) Allowed variations for holes, for roundness, eccentricity, plumb line

deviation, shall be as follows:- - Maximum deviation for spacing of two holes on the same axis shall be

+1mm. (k) Two perpendicular diameters of any oval hole shall not differ by more

than 1mm. Drilling faults may be rectified by reaming holes to the next upper diameter. In such case, spacing of new hole centers and distance of hole centers to the edge of members shall not be less than allowed. Also, the increase of hole diameter shall not impair the structural strength.

(l) Hole reaming shall be allowed, if the number of faulty holes does not

exceed 15% of the total number of holes at one joint.

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6.2.7 Assembling

(a) Before making holes in individual members, the steel work intended to be bolted together shall be assembled, clamped properly and tightly, so as to ensure close abutting or lapping of the surfaces of the different members.

(b) The abutting joints shall be cut, dressed true and straight and fitted close together. (c) All stiffeners shall bear tightly, both at top and bottom without being drawn or caulked. (d) Column splices and butt joint of compression members shall be

accurately machined and close butted over the whole section. (e) In column caps and bases, the ends shall be accurately machined so that

the parts connected, butt against each other over the entire surfaces of contact.

(f) Connecting angles or channels shall be fabricated and placed in position

with great accuracy, so that they are not unduly reduced in thickness by machining.

(g) The component parts shall be assembled and aligned in such a manner

that they are neither twisted nor otherwise damaged. (h) Specified camber if any shall be provided. (i) Proper clamps, clips, jigs and other fasteners shall be placed, so as to

avoid any distortion in the members and to ensure their correct positioning.

(j) Proper care shall be taken for welding shrinkage and distortion, as the

drawings show the finished dimensions of the structures.

7.0 WELDING

7.1 General 7.1.1 Welding shall be in accordance with IS 816, IS 819, IS 1024, IS 1261, IS 1323

and IS 9595 as appropriate.

7.1.2 The LSTK CONTRACTOR shall make necessary arrangement for providing

sufficient number of welding sets of the required capacity, all consumables, cutting and grinding equipment with requisite accessories, auxiliaries, equipment and materials required for carrying out various tests such as dye penetration, magnetic particle, ultrasonic, etc.

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7.1.3 Adequate protection against rain, snow and strong winds shall be provided to

the welding personnel and the structural members during welding operation. In the absence of such a protection no welding shall be carried out. The electrodes and parts being welded shall be dry.

7.1.4 It shall be the responsibility of the LSTK CONTRACTOR to ensure that all

welding is carried out in accordance with this specification and relevant IS Codes. The LSTK CONTRACTOR shall provide all the supervision to fulfill this requirement.

7.2 Preparation of Members for Welding 7.2.1 Edge Preparation

Edge preparation, beveling of fusion faces for welding shall be done strictly as per the dimensions shown in the drawings. In case, the same are not indicated, edges shall be prepared as per the details given in IS 9595. Beveling of fusion faces shall be approved by the Engineer-In-Charge. The tolerances on limits of gap, root face and included angle shall be as per IS 9595. Edge preparation for welding shall be carefully and accurately made so as to facilitate a good joint. Generally no special edge preparation shall be required for members under 8mm thick.

7.2.2 Cleaning

Welding edges and the adjacent areas of the members, extending upto 20mm, shall be thoroughly cleaned of all oil, grease, scale and rust and made completely dry. Gaps between the members to be welded shall be kept free from all foreign matter.

7.2.3 Preheating

Preheating of members, shall be carried out as per IS 9595 when the base metal temperature is below the requisite temperature for the welding process being used. Preheating shall be done in such a manner that the parts, on which the weld metal is being deposited, are above the specified minimum temperature for a distance of not less than 75mm on each side of the weld line. The temperature shall be measured on the face opposite to that being heated. However, when there is access to only one face, the heat source shall be removed to allow for temperature equalization (1 minute for each 25mm of plate thickness) before measuring the temperature.

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7.2.4 Grinding

(a) Column splices and butt joints of compression members shall be

accurately ground and close-butted over the entire section to ensure full contact for load transmission.

(b) In case of column bases and caps, the ends of the section along with

connected gussets, angles, channels etc shall be accurately ground, so that the parts connected, butt over the entire surface of contact.

(c) The fitting of gussets, connecting angles, channels etc, shall be sufficiently accurate, to limit the reduction in thickness on account of grinding to 2mm.

(d) Ends of all bearing stiffeners shall be ground to fit tightly at both top and

bottom. (e) Column bases and cap plates shall be accurately ground over the bearing

surfaces to ensure an effective contact with the ends of columns. (f) Bearing faces which are to be grouted directly to the foundations need

not be ground if such faces are true and parallel to the upper faces. 7.3 Welding Processes

Welding of various materials under this specification shall be carried out using one or more of the following processes. - Manual Metal Arc Welding Process - Submerged Arc Welding Process - Gas Metal Arc Welding Process - Flux Cored Arc Welding Process The welding procedure adopted and consumables used shall be specifically approved by the Engineer-In-Charge. A combination of different welding / processes or a combination of electrodes of different classes / makes may be employed for a particular joint only after qualifying the welding procedures to be adopted and obtaining the approval of the Engineer-In-Charge.

7.4 Types of welding 7.4.1 Fillet Weld

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The cross section of fillet weld is like a triangle and it is used to join two surfaces normally at right angle to each other. This type of weld is used more frequently in structural connections than any other type, and is usually in the form of isosceles triangle. The fillet welds shall be continuous or intermittent as specified in the drawings.

7.4.2 Butt Welds

These are classified according to the method of grooving or preparing of the base metal. The parts to be welded shall be filed or chiseled to the required shape, for butt welding at the throat.

7.5 Welding Plant 7.5.1 General

The welding plant and equipment shall be of the best type and of modern design and shall be approved by the Engineer-In-Charge. Either direct or alternating current (but not both kinds) may be used throughout the work. An ammeter shall be provided to each arc and so situated that the Engineer-In-Charge can check easily the current being used by the operator. Each welder may be supplied with portable current regulator to enable him to adjust the welding current within the approved limits without leaving his work.

7.5.2 Electrodes

The maximum diameter of Electrodes for welding shall be, as stated below unless otherwise specified.

Average thickness of plate or section Maximum dia of Electrodes

to be used

Less than 5mm 3.2 mm

5mm upto but not including 8mm 4.0 mm




25mm and over 9.0 mm

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7.6 Approval and Testing of Welders

The LSTK CONTRACTOR shall satisfy the Engineer-In-Charge that only qualified operators shall be employed for welding. For this purpose the welders shall have satisfied the relevant requirements of IS 817, IS 7310 and IS 7318. Adequate means of identification shall be provided to enable each weld to be traced to the welder by whom it was made. The LSTK CONTRACTOR shall intimate the Engineer-In-Charge sufficiently in advance, the commencement of tests, to enable him to be present to witness the same.

7.7 Approval and Testing of Welding Procedures

The LSTK CONTRACTOR shall carry out procedure tests in accordance with IS 7307 to demonstrate by means of a specimen weld of adequate length on steel representative of that to be used, that he can make welds with the welding procedure to be used for the work to the complete satisfaction of the Engineer-In-Charge. The test weld shall include weld details from the actual construction and it shall be welded in a manner simulating the most unfavorable instances of fit-up, electrode condition etc which are anticipated to occur on the particular fabrication. The test weld shall be held at ambient temperature for a minimum period of 72 hours prior to testing and shall be as per IS 7307. After establishing the welding method, the LSTK CONTRACTOR shall finally submit to the Engineer-In-charge for his approval the welding procedure specification in standard format given in IS 9595 before starting the fabrication.

7.8 Sequence of welding 7.8.1 As far as practicable, all welds shall be made in a sequence that will balance the

applied heat of welding while the welding progresses, to reduce distortion. 7.8.2 The direction of the general progression in welding or a member shall be from

points where the parts are relatively fixed in position with respect to each other, towards points where they have a greater relative freedom of movement.

7.8.3 All splices in each component part of a cover plated beam or built up member

shall be made before the component part is welded to other component parts of the member.

7.8.4 Joints expected to have significant shrinkage shall be welded before joints

expected to have lesser shrinkage.

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7.8.5 Welding shall be carried continuously to completion with correct number of runs. 7.8.6 The LSTK CONTRACTOR shall choose the welding sequence after carefully

studying each case such as to minimize distortion and shrinkage. The welding sequence shall be approved by Engineer-In-Charge.

7.9 Welding Procedure 7.9.1 After the fusion faces are carefully aligned and set with proper gaps, the root

pass of butt joints shall be executed properly so as to achieve full penetration with complete fusion of the root edges.

7.9.2 On completion of each run, all slag and spatters shall be removed. The weld and

adjacent base metal shall be cleaned by wire brushing and light chipping. Visible defects such as cracks, cavities and other deposition faults, if any, shall be removed upto sound metal before depositing subsequent run of weld.

7.9.3 All full penetration butt welds shall be completed by chipping / gouging upto

sound metal and then depositing a sealing run of weld metal on the back of the joints. Where butt welding is practicable from one side only, suitable backing steel strip shall be used and joint shall be arranged in such a way as to ensure that, complete fusion of all the parts is obtained.

7.9.4 While welding is in progress, care shall be taken to avoid any kind of movement of the components, shocks, vibrations to prevent occurrence of weld cracks.

7.9.5 Any deviation desired from the recommended welding technique and electrodes

shall be adopted only after approval of the Engineer-In-Charge.

7.9.6 The welding of seams, discontinued due to some reasons, the end of the discontinued seam shall be melted in order to obtain a good continuity. Before resuming the welding operation, the groove as well as the adjacent parts shall be well cleaned for a length of approximate 50mm.

7.9.7 For single butt welds and double butt welds, the re-welding of the root is

mandatory but only after the metal deposits on the root has been cleaned by back gauging or chipping. The welding seams shall be left to cool slowly. The LSTK CONTRACTOR shall not be allowed to cool the welds quickly by any method.

7.9.8 All welds shall be free from defects like blowholes, slag inclusion, lack of

penetration, under cutting, cracks etc. All welds shall be cleaned of slag and flux. These shall show uniform sections smoothness of weld metal, feather edges without overlap and freedom from porosity. The defects in welds shall be rectified according to IS 9595 and as per instruction of Engineer-In-Charge, without damaging the parent metal.

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When the crack in the weld is removed, magnetic particle injection or any procedure instructed by Engineer-In-Charge shall be used, to ensure that the whole of the crack has been removed.

7.9.9 Members to be joined by fillet welds, shall be brought and held as close as possible and in no event shall be separated by more than 3mm. If the separation is 1.5mm or more, the fillet weld size shall be increased by the amount of separation.

7.9.10 In joints connected by fillet welds, the minimum sizes of single run fillet welds or

first run shall conform to requirements of IS 813 and IS 816. Fillet welds larger than 8mm shall be made with two or more passes.

7.10 Precautions

All operations connected with welding and cutting equipment shall conform to the safety requirements given in IS 818.

7.11 Operation and workmanship

7.11.1 Welds shall be made in the flat position whenever practicable. 7.11.2 Arc length, voltage and current shall be suited to the thickness of material, type

of groove and other circumstances of the work. 7.11.3 Freedom of movement of one member of the joint shall be allowed wherever

possible. Wherever joints shall be welded, allowance shall be made for the movement of one component, to the order of 1.5 mm.

7.11.4 The electrode manipulation during welding shall be such as to ensure that:

(a) The base metal is in a fused state when the filler metal makes contact with

it. (b) The filler metal does not over-flow upon any infused base metal. (c) The base metal is not under-cut along with weld edges. (d) The flowing metal floats the slag, oxides and gas bubbles to the surface

behind the advancing pool. In case any of these requirements is unattainable by manipulation, the current shall be adjusted or the electrode size changed.

Each time the arc is started, the electrode shall be moved in such a way that the fusion of base metal at the starting point is assured. At the completion of a run the movement of electrode shall be slowed down to fill the arc crater.

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After every interruption of the arc except at completion of a run, the arc shall be restarted ahead of the previous deposit and then moved back to fill the crater. Any such alternative technique shall be used, as will ensure complete filling of the crater or complete fusion between the new and old deposits of the base metal at the point of junction and result in continuity of weld. Before welding operation is completed, all traces of slag shall be removed from the deposit, by chipping if necessary, the deposit. The adjoining base metal shall be wire brushed and cleaned at all points. The requirements shall apply not only to successive layers, but also to successive beads and to the overlapping area wherever a junction is made on starting a new electrode.

(e) The welds shall be free from cracks, discontinuity in welding and other

defects such as (i) under-size (ii) over-size (iii) under-cutting and (iv) over-cutting in the case of fillet welds, and defects (ii), (iii) & (iv) in the case of butt welds.

All defective welds considered harmful to the structural strength shall be cut out and re-welded.

Finished welds and adjacent parts shall be protected with clean boiled linseed oil or other suitable means as directed by Engineer-In-Charge after all slag has been removed.

Welds and adjacent parts shall be painted after the Engineer-In-Charge approves the same.

7.12 Inspection and Testing of Welds 7.12.1 General

The method of inspection shall be according to IS 822 and extent of inspection and testing shall be in accordance with the relevant application standard or as specified by the Engineer-In-Charge. Welds shall not be painted or otherwise obscured until they have been inspected, approved and accepted. The Engineer-In-Charge shall have access to the LSTK CONTRACTORs work at all reasonable times and the LSTK CONTRACTOR shall provide him with all facilities necessary for inspection during all stages of fabrication and erection with, but not limited to, the following objectives. (a) To check the conformity with the relevant standards and suitability to

various welding equipments and their performance. (b) To witness / approve the welding procedure qualification. (c) To witness / approve the welders performance qualification.

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(d) To check whether shop / field welding being executed is in conformity with the relevant specifications and codes of practice.

7.12.2 Visual Inspection

All finished welds shall be visually inspected. The following types of weld defects and faults shall be inspected. (a) Weld defects occurring at the surface such as blow holes, exposed

porosity, infused welds, etc. (b) Surface cracks in the weld metal or in the parent metal adjacent to it. (c) Damages to the parent metal such as undercuts, burning, overheating etc. (d) Profile defects such as excessive convexity or concavity, overlapping,

unequal leg lengths, excessive reinforcement, incompletely filled grooves, excessive penetration beads, root grooves, etc.

(e) Distortion due to welding i.e., local shrinkage, camber, bowing, twisting, rotation, wariness etc. (f) Linear eccentric, angular and rotational misalignment of parts. (g) Dimensional errors. The size of the specified weld may be slightly over but not under.

7.13 Mechanical Tests

The mechanical testing shall be done in accordance with the relevant standards and as per the instructions of the Engineer-In-Charge. (a) Bend Testing (for ductility)

The elongation shall be not less than 30 percent for stress relieved welds and not less than 25 percent for non-stress relieved welds.

(b) Tensile Testing (Reduced section tensile testing)

The tensile strength shall be not less than the specified tensile strength of the parent metal.

7.14 Magnetic Particle / Dye Penetration / Ultrasonic Examination:

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The examination shall be done at random on joint locations as directed by the Engineer-In-Charge. The tests shall be carried out by employing approved testing procedure in accordance with IS 822.

7.15 Radiographic Examination

Radiographic examination shall be carried out only in special cases for random joints as directed by the Engineer-In-Charge. The LSTK CONTRACTOR shall be paid extra for such examination except for penalty radiographic tests for which the cost shall be borne by him. The LSTK CONTRACTOR shall make necessary arrangement at his own expense, for providing the radiographic equipment, films and all other necessary materials required for carrying out the examination. The tests shall be carried in the presence of the Engineer-In-Charge by employing approved testing procedure in accordance with IS 822. The LSTK CONTRACTOR shall fulfill all the statutory safety requirements while handling x-ray and Gamma-ray equipment and provide the Engineer-In-Charge all the necessary facilities at site such as dark room, film viewer etc., to enable him to examine the radiographs.

7.16 Repair of Faulty Welds

Welds not complying with the acceptance requirements, as specified by IS Codes and the Engineer-In-Charge, shall be corrected in part or whole either by removing and replacing or as follows: (a) Excessive convexity : Reduce to size by removal of excess weld

metal. (b) Shrinkage cracks, cracks : Defective portions to be removed upto sound metal and in parent plates and craters

rewelded. (c) Under cutting : Additional weld metal to be deposited. (d) Improperly fitted / : Welding to be cut and edges suitably

prepared and parts misaligned parts rewelded.

(e) Members distorted by : Member to be straightened by mechanical means or by the heat of welding careful application of limited amount of heat. In removing defective parts of a weld, gouging, chipping, oxygen cutting or grinding shall not extend into the parent metal to any substantial amount beyond the depth of weld penetration, unless cracks or other defects exist in the parent plates. The weld or parent plates shall not be undercut in chipping, grinding, gouging or oxygen cutting.

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Repair of defective welds shall be carried out with the approval of the Engineer-In-Charge.

7.17 Splicing 7.17.1 splicing of built up / compound sections shall be done in such a way, that each

component of the section is joined in a staggered manner.

7.17.2 Where no butt weld is used for splicing, the meeting ends of two pieces of joist / channel / built up section shall be ground flush for bearing on each other. Suitable flange and web splice plates shall be designed and provided for the full strength of the flange / web of the section and welds designed accordingly.

7.17.3 Where full strength butt weld is used for splicing of members fabricated out of joist / channel / built up section, additional flange and web plates shall be provided, over and above the full strength butt welds, to have 40% strength of the flange and web.

7.17.4 Where a cover plate is used over a joist / channel section, the splicing of the cover plate and channel / joist sections shall be staggered by minimum 500mm. Additional splice plate shall be used for the cover plate and joist/channel section as per clause mentioned above.

8.0 BOLTING 8.1 General

Standard M.S. Bolts conforming to IS 1363 shall be used for field connection. Unthreaded bolt shall bear on the members assembled. All bolts shall be provided with washers of sufficient thickness under the nuts so that no part of the threaded portion of the bolts is within the thickness of the parts bolted together. All bolt heads and nuts shall be hexagonal and of uniform size, unless specified otherwise. The screwed threads shall conform to IS 1363 and the threaded surface shall not be tapered. The bolts shall be of such length as to project two clear threads beyond the nuts when fixed in position and these shall fit in the holes properly. The nuts shall fit in the threaded ends of bolts properly. Flat washers shall be circular and of suitable thickness. However where bolt heads / nuts bear upon the beveled surfaces, they shall be provided with square tapered washers of suitable thickness to afford a seating square with the areas of the bolt. All high strength bolts shall be conforming to IS 3757. Method of fixing for such bolts shall be in accordance with IS 4000.

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Bolts, nuts and washers shall be thoroughly cleaned and dipped in double boiled linseed oil, or by other means to protect from rusting as directed by Engineer-In-Charge, before use.

8.2 Preparation of members for bolting

All members shall be assembled for bolting with proper jigs and fixtures, to sustain the assemblies without deformation and bending. Before assembly, all sharp edges, shavings, rust, dirt etc. shall be removed and approved by the Engineer-In-Charge. Before assembly, the contacting surfaces of the members shall be cleaned and given a coat of primer paint as per IS 2074 or as directed by Engineer-In-Charge.

8.3 Bolting Up

Final bolting of the members shall be done after the defects have been rectified and approval of joints obtained. The bolts shall be tightened, starting from the centre of joint towards the edge. Erection bolts shall not be removed before other bolts are set.

8.4 Check Assembly

The members, which are bolt assembled, shall be set according to drawings and temporarily fastened with erection bolts to check the co-axiality of the holes. The members shall be finally bolted, after the deviations have been corrected. The difference in thickness of the sections that are butt assembled shall not be more than 3% or maximum 0.8 mm whichever is less. If the difference is larger, grinding or filing shall correct it. Reaming of holes to final diameter or cleaning of these shall be done, only after the parts have been checked for assembly.

9.0 MISCELLANEOUS FABRICATION ACTIVITIES 9.1 Plaining of Ends

Grinding when so specified in the design shall do plaining of ends of members like column ends. Plaining of butt welded members shall be done, after these have been assembled. The sharp edges shall be removed with grinding machines or files. The following tolerances shall be permitted on member that has been plained.

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- On the length of the member having both ends plained, maximum + 2 mm

with respect to drawings. - Level differences of plained surfaces, maximum 0.3 mm.

- Deviation between plained surface and member's axis, maximum L/1500.

9.2 Holes for Field joints

Holes for field joints shall be drilled in the shop, to final diameters and tested in the shop, with trial assemblies. When three dimensional assembly is not possible in the shop, the holes for field joints may be drilled in shop and reamed on site during erection, on approval by the Engineer-In-Charge. For bolted steel structures, trial assembly in shop is necessary. The tolerance for spacing of holes shall be +/- 1 mm.

9.3 Marking for identification All elements and members shall be shop marked, prior to dispatch for erection. The members shall be visibly marked with a weatherproof light colored paint. The size and thickness of the numbers shall be chosen, as to facilitate the identification of members. For small members that are delivered in bundles or crates, the required marking shall be done on small metal tags securely tied to the bundle. The crates shall be marked individually. Each bundle or crate shall be packed with members for one and the same assembly. In the same bundle or crate, utility members such as bolts, gussets etc. may be packed. All bill of materials showing weight, quality and dimension of contents shall be placed in the crates. The marking and job symbol shall be registered in all shop delivery documents.

9.4 Shop Test Pre-Assembly

For steel structures that have the same type of welding, the shop test preassembly shall be performed at least on one out of every 10 members. In case if one member does not meet the limiting deviations specified in the general specification in pre-assembly shop test, all members shall be shop tested.

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For bolted steel structures, shop test pre-assembly is mandatory for all elements, as well as for the entire structure in totality.

10.0 SHOP INSPECTION AND APPROVAL 10.1 General

The Engineer-In-Charge shall have free access at all reasonable times to the fabrication shop and shall be provided all necessary facilities for satisfying him that the fabrication is being undertaken in accordance with drawings and specifications. Technical approval of the steel structure in the shop by the Engineer-In-Charge is mandatory. The LSTK CONTRACTOR shall not limit the number and kinds of tests, final as well as intermediate tests or extra tests requested by the Engineer-In-Charge. All necessary tools, gauges, instruments etc. and technical, non-technical personnel shall be furnished for shop tests to the Engineer-In-Charge at LSTK CONTRACTOR's cost as and when required by the Engineer-In-Charge.

10.2 Shop Acceptance

The Engineer-In-Charge shall inspect and approve at the following stages.

(a) Intermediate Approval

Intermediate approval of work shall be given when a part of the work performed cannot be inspected later or when inspection would be difficult to perform and results would not be satisfactory.

(b) Partial Approval

Partial approval in the shop is given to members and assemblies of steel structures before the primer coat is applied and includes:-

- Approval of field joints

- Approval of parts with plained surfaces

- Test erection

- Approval of members

- Approval of markings

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- Inspections and approvals of special features like rollers, loading platform mechanism etc. During the partial approval, intermediate approvals as well as all former approvals, shall be taken into consideration.

(c) Final Approval

The final approval in the shop, refers to all elements and assemblies of the steel structures, with shop primer coat, ready for delivery from shop, to be loaded for transportation or stored.

The final approval comprises of:

- Partial approvals - Approval of shop primer coat - Approval of mode of loading and transport, approval of storage.

11.0 INSPECTION ON SITE

LSTK CONTRACTOR shall give due notice to Engineer-In-Charge in advance of structural members or workmanship getting ready for inspection. All rejected material shall be promptly removed from the shop and replaced with new material for Engineer-In-Charge approval. The fact that, certain material has been accepted shall not invalidate final rejection at site by Engineer-In-Charge if it fails to be in proper condition, or has fabrication inaccuracies, which prevents proper assembly. No material shall be painted or dispatched to site without inspection and approval by Engineer-In-Charge. Shop inspection by Engineer-In-Charge or submission of test certificate and acceptance thereof by Engineer-In-Charge shall not relieve LSTK CONTRACTOR from the responsibility, of furnishing fabricated material conforming to requirements of these specifications, nor shall it invalidate any claims which Engineer-In-Charge may make because of defective, unsatisfactory workmanship. For fabrication work carried out on the field, the same standard of supervision of quality control shall be maintained as in shop fabricated work. Inspection and testing shall be conducted in a manner satisfactory to Engineer-In-Charge. Members shall be inspected at all stages of fabrication and assembly to verify that the dimensions, tolerances, alignment, surface finish etc. are in accordance with the requirements shown on drawings and as per IS codes.

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In the event of any failure of member, to meet an inspection or test requirement, LSTK CONTRACTOR shall notify Engineer-In-Charge. The quality control procedure to be followed, to ensure satisfactory repair shall be subject to approval by Engineer-In-Charge. In such cases, Engineer-In-Charge has right to specify additional inspection or testing as deemed necessary and the additional cost of such testing shall be borne by LSTK CONTRACTOR. Holes in members required for installing equipment or steel furnished by other manufacturers or other LSTK CONTRACTORs, shall be drilled in LSTK CONTRACTOR's shop as part of the contract, the information for which will be supplied before fabrication.

12.0 PACKING, TRANSPORTATION, DELIVERY

After final shop acceptance and marking, the items shall be packed and loaded for transportation. Packing must be adequate to protect items against warping during loading and unloading. Proper lifting devices shall be used for loading, in order to protect items against warping. Slender projecting parts shall be braced with additional steel bars, before loading, for protection against warping during transportation. Loading and transportation shall be done in compliance with transportation rules. If certain parts cannot be transported in lengths stipulated in the drawings, Engineer-In-Charge shall approve the position and type of additional splice joints. Damaged parts and members, due to transportation may be rejected by Engineer-In-Charge and re-fabricated at site or at shop and redelivered at LSTK CONTRACTOR's cost. Items shall be carefully loaded on platforms for transportation, to prevent warping, bending or falling, during transportation. The small parts such as fishplates, plates, gussets etc. shall be securely tied with wire to their respective parts. Bolts, nuts and washers shall be packed and transported in crates. The parts shall be delivered in the order, stipulated by the Engineer-In-Charge and shall be accompanied by document showing:

- Quality and quantity of structural members - Position of member in the structure - Particulars of structure - Identification number / job symbol

13.0 STORAGE AND PREPARATION PRIOR TO ERECTION.

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The storage place for steel parts shall be prepared and got approved by the Engineer-In-Charge, before the steel structures start arriving from the shop. The LSTK CONTRACTOR shall provide a platform, near the erection site, for erection work. The LSTK CONTRACTOR shall make the following verifications upon receipt of material at site:

- For quality certificate regarding materials and workmanship according to

the general specifications and drawings. - Whether parts received are complete without defects due to transportation,

loading, unloading and whether the defects if any are well within the permissible limits.

For the above work sufficient space must be allotted in the storage area. The storage area shall be clean, free of water / moisture and shall be approved by Engineer-In-Charge. Precautions shall be taken to prevent warping of items during unloading. The parts shall be unloaded, sorted and stored so as to be easily identified. The parts shall be stored according to construction symbols and markings, so that these may be taken out in order of erection sequence. The parts shall be set at least 150 mm clear from ground on wooden or steel blocks for protection against direct contact with ground moisture. If minor rectification of members like straightening etc. are required, these shall be done in a special place allotted, which shall be adequately equipped. The parts shall be clean when delivered for erection.

14.0 ERECTION 14.1 General

The erection work shall be permitted only after the foundation or other structure over which the steelwork shall be erected is ready for erection. The LSTK CONTRACTOR shall satisfy himself about the levels, alignment, location of the pedestals, columns, brackets, anchor bolts etc well in advance, before starting the erection. Minor chipping, adjusting the anchor bolts etc. shall be carried out by the LSTK CONTRACTOR at his expense. Any faulty erection done by the LSTK CONTRACTOR shall be made good at his own cost. The LSTK CONTRACTOR shall submit, well in advance a detailed erection program.

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Steel shall be handled carefully on the field, so as not to be damaged and to avoid scratches, abrasion. Scratched or abraded steel shall be given a coat of the primer previously applied on the same member. All structural steel shall be erected as shown on the drawings, plumb and true to line and levels. This shall be checked before and after connections are made. All erection shall be subject to approval of Engineer-In-Charge. Positioning and leveling of the structure, alignment, plumbness and fixing every member of the structure shall be in accordance with the relevant drawings and to the complete satisfaction of the Engineer-In-Charge. The following checks and inspection shall be carried out before, during and after erection.

- Damages during transportation - Accuracy of alignment of structures - Erection according to drawings and specifications - Progress and workmanship

In case there are any deviations, regarding positions of foundations or anchor bolts, which would lead to erection deviations, the Engineer-In-Charge shall be informed immediately. Minor rectifications in foundations, orientation of bolt holes etc. shall be carried out as a part of the work, at no extra cost. The various parts of the steel structure shall be so erected, as to ensure stability against inherent weight, wind and erection stresses. The structure shall be anchored and final erection joints completed, after plan and elevation positions of the structural members have been verified with corresponding drawings and approved by the Engineer-In-Charge.

The bolted joints shall be tightened, so that the entire surface of the bolt heads and nuts shall rest on the member.

14.2 Hoisting and Erection

Steelwork shall be hoisted and erected in position carefully, without any damage to itself, other works and injury to workmen. The method of hoisting and erection proposed to be adopted by the LSTK CONTRACTOR, shall be got approved from the Engineer-In-Charge. The approval of the Engineer-In-Charge however, shall not relieve the LSTK CONTRACTOR from his responsibility for the work being carried out in a safe and proper manner, without unduly stressing the various members. Proper mechanical appliances such as derricks, cranes, lifting tackles, winches, ropes etc. shall be used.

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Frames shall be lifted at such points, that they are not liable to buckle, deform or unduly stressed. The steelwork may be erected in suitable units as may be directed by the Engineer-In-Charge.

During erection, the steelwork shall be securely bolted or otherwise fastened. Wherever necessary, temporarily braces shall be provided for all loads to be carried by the structure during erection, including those due to erection equipment and its operations. The steelwork shall be placed in proper position as per approved drawings. No permanent bolting shall be done until proper alignment has been obtained. The structure or the part of it placed in position shall be secured against overturning or collapse by suitable means. Proper access, platform and safety arrangement shall be provided by the LSTK CONTRACTOR, for working, inspection at his own expense as per the direction of Engineer-In-Charge.

15.0 ERECTION TOLERANCES

Maximum Permissible Erection Tolerances is stated below.

Description Variation

A. Columns and Roof Posts

1. Deviation of column axes at foundation top level with respect to true axes.

i) In longitudinal direction + 5mm

ii) In lateral direction + 5mm

2. Deviation in the level of bearing surface of columns at foundation top with respect to true level.

+ 5mm

3. Out of plumbness of column axis from true vertical axis, as measured at top :

i) Upto and including 30m height. + H or +25mm 1000 whichever is less.

ii) Over 30m height. + H or +35mm 1200 whichever is less.

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4. Deviation in straightness in longitudinal and transverse planes of column at any point along the height.

+ H or +10mm 1000 whichever is less.

5. Difference in the erected positions of adjacent pairs of columns along length or across width of building prior to connecting trusses / beams with respect to true distance.

+ 5mm


6. Deviation in any bearing or seating level

with respect to true level.

+ 5mm

7. Deviation in difference in bearing levels of member on adjacent pair of columns both across and along the building.

+ 5mm

B. Trusses

1. Shift at the centre of span, of top chord with respect to the vertical plane passing through the centre of bottom chord.

+ 1 of height of truss 250 truss in mm at centre of span or + 15mm whichever is less.

2. Lateral shift of top chord of truss, at the centre of span from the vertical plane passing through the centre of supports of the truss.

+ 1 of span of truss 1500 truss in mm or + 10mm whichever is less.

3. Lateral shift in location of truss from its true vertical position.

+ 10mm.

4. Lateral shift in location of purlin from true position.

+ 5mm

5. Deviation in difference of bearing levels of truss from the true difference.

+ 1 of Span of truss 1200 truss in mm or + 20mm whichever is less.

C. Gantry Girders and Rails

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1. Shift in the centre line of crane rail with respect to centre line of web of gantry girder.

+ Web thickness of girder + 2 mm 2

2. Shift of alignment of crane rail (in plan) with respect to true axis of crane rail at any point.

+ 5mm

3. Deviation in crane track gauge with respect to true gauge.

i) For track gauge upto and including 15m.

+ 5mm


ii) For track gauge more than 15m.

+ 10mm

4. Deviation in the crane rail level at any point from true level.

+ 10mm

5. Difference in levels between crane track rails (across the bay) at

i) Supports of gantry girders 15mm

ii) Mid span of gantry girders 20mm

6. Relative shift of crane rail surfaces (at a joining) in plan and elevation.

2mm

16.0 ANCHOR BOLTS 16.1 Material

(a) Anchor bolts shall be turned from plain and mild conforming to IS 432 grade 1.

(b) Nuts and lock nuts (hexagonal type) shall be of grade B as per IS 1367

and conform to IS 1363. (c) Washers shall be of mild steel conforming to IS 2016. (d) Pipe sleeves shall be of mild steel tubes (medium duty) conforming to IS

1239.

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(e) Anchor plates and ribs shall conform to IS 2062.

16.2 Fabrication

Fabrication of anchor bolts and their complete assemblies shall be strictly in compliance with the specifications and drawings. Anchor bolts shall have coarse type threads conforming to IS 4218.

16.3 Placement

Anchor bolts assemblies shall be placed in position strictly as per drawings and securely held during pouring and vibrating of concrete with necessary templates and other dummy structures to prevent their dislocation.

16.4 Tolerances

Tolerances allowed for anchor bolts positioning shall be: - For sleeved bolts, one tenth of the bolt nominal diameter. - For bolts without sleeves, one twentieth of the bolt nominal diameter.

16.5 Protection

The exposed surfaces of bolts shall be properly covered (after greasing of bolts and packing of sleeves) with jute cloth so as to protect them from damage.

17.0 M.S. INSERTS / CORNER ANGLES 17.1 Material (a) MS inserts / corner angles shall be of mild steel conforming to IS 2062. (b) Lugs shall be of mild steel bars conforming to IS 432 Grade 1. 17.2 Fabrication

Fabrication of inserts / corner angles shall be done strictly as per drawings and in compliance with the requirements given in specification.

17.3 Placement

MS inserts / corner angles shall be correctly embedded as per their location shown in the drawings. Care shall be taken that these are securely held in position and do not get disturbed during concreting. Where necessary, these may be welded to the reinforcement bars. Suitable templates, spacers, dummy structures and temporary staging shall be provided. Necessary cutting in the

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form work and adjustment of reinforcement bars shall be affected for the placement of inserts / corner angles where required.

18.0 CHEQUERED PLATES 18.1 Material

The material shall conform to IS 2062.

18.2 Fabrication

Chequered plate shall be fabricated as per the Approved for Construction fabrication drawings (prepared by the LSTK CONTRACTOR based on design drawings). These shall be perfectly flat and without any dents / deformations and shall be cut to the required size and shape. Holes / notches / openings of the required size shall be provided as per the drawings. Nosing for staircase treads shall be made by cold bending of chequered plates. All dges shall be made smooth and even. All chequered plate units shall be given distinct erection marks in accordance with the marking drawings.

18.3 Erection / Fixing

Chequered plates shall be fixed to the bearing members by welding / bolting as shown in the drawings.

19.0 GRATING 19.1 Categories

The gratings shall be of two categories:- i) Category A Fabricated by the LSTK CONTRACTOR as per design

drawing / standards. ii) Category B Ready made bought out from an approved manufacturer.

19.2 Material

Gratings shall be of mild steel flats conforming to IS 2062.

19.3 Fabrication 19.3.1 Category A Gratings

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These shall be fabricated strictly as per the Approved for Construction fabrication drawings prepared by the LSTK CONTRACTOR based on design drawing and standards. All units shall be given distinct erection marks in accordance with the marking drawing.

19.3.2 Category B Gratings

These shall be as per manufacturers details designed to carry loads as specified in the design drawing supplied to the LSTK CONTRACTOR. The deflection shall not exceed span / 200 or 6mm whichever is minimum. The maximum clear size of voids in the grating be limited to 30mm x 55mm. The LSTK CONTRACTOR shall make necessary notches / opening in the gratings as shown on the drawings. All edges affected by such notches / openings shall be suitable stiffened by welding additional flats of the requisite size. All units shall be given distinct erection marks in accordance with the marking drawings. Before procurement the LSTK CONTRACTOR shall submit the design calculations, drawings and manufacturers literature catalogues and get the same reviewed by the Engineer-In-Charge.

19.4 Erection / Fixing Gratings shall be fixed to the bearing members by welding / clamping as indicated in the drawings.

20.0 HAND RAILING 20.1 Material

a) Tubes for hand railing shall be 32mm nominal diameter of mild steel medium grade conforming to IS 1239.

b) Toe plates and mid plates shall be of mild steel conforming to IS 2062. c) Posts shall be of mild steel angle conforming to IS 2062.

20.2 Fabrication

Hand railing shall be fabricated strictly as per the Approved for Construction fabrication drawings prepared by the LSTK CONTRACTOR based on design drawings and standards. All tubes shall be straight and without any dents / deformations. Tubes shall be cut and ends shall be prepared to a neat and workman like finish. All elements shall be directly welded. Tubes shall be cold bent to shape and curvature in case of discontinuous ends of handrails. Lower ends of vertical posts shall be cut and splayed (for grouting in pockets provided

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in the concrete members). For removable type of hand railing, suitable base plates (with provision for bolting) shall be welded to the lower end of vertical posts. Chequered plates and gratings shall be suitably notched to accommodate vertical posts / their base plates wherever required. All units shall be given distinct erection marks in accordance with the marking drawings.

20.3 Erection / Fixing

Hand railing shall be fixed to the bearing members by welding / bolting / grouting as indicated in the drawings.

21.0 STAIRCASE AND LADDERS

Structural steel staircase and ladders wherever shown on drawings shall be complete with stringers, treads, risers, struts, hangers, bracing, gratings, toe plates, railings and all fastenings and fittings as per standard drawings. All work shall be shop fabricated as far as possible before erection. All work shall be erected square, plumb, straight and true. Joints and intersections shall be accurately fitted and securely braced or anchored.

22.0 MILD STEEL RUNGS 22.1 Materials

Mild steel rounds for rungs shall be of 20mm diameter conforming to IS 432 Grade 1.

22.2 Fabrication

Rungs shall be fabricated as per standards / drawings. Mild steel bars shall be straightened if required, cut, bent to shape and given primer paint.

22.3 Fixing

Rungs shall be fixed in position as per detailed drawing and firmly tied / welded with reinforcement to prevent their displacement during vibrating of concrete.

23.0 EXPANSION FASTENERS 23.1 Material

Expansion fasteners (medium and heavy duty) shall be of mild steel / high tensile steel with rust proof coating.

23.2 Classification

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The expansion fasteners shall be designated as medium and heavy duty depending on their usage. The broad classification is given below for general guidance.

23.2.1 Medium Duty (Mild steel / High tensile steel) - Ladders and stairs supports - Cables and cable trays supports - Electrical panels and fixtures - Hangers for pipes and cable trays - Pipe supports 23.2.2 Heavy Duty (Mild Steel / High tensile steel) - Platform supports (beam and columns) - Knee brackets for pipes / multi tiers cable trays / walkways etc. 23.3 Limitations

Expansion fasteners shall not be used for:

- Members supporting equipments and pipes subjected to vibrations - Cantilever connections designed to cater for effective cantilever spans greater than 1000 mm and 1000 kgs of concentrated load of the free end. 23.4 Selection

The LSTK CONTRACTOR shall submit to the Engineer-In-Charge manufacturers catalogues along with the specimen expansion fasteners (proposed to be used for the job) for his selection and approval. Selected fasteners shall be capable to carry the specified loads.

23.5 Testing

If so required by the Engineer-In-Charge, the LSTK CONTRACTOR shall satisfy the Engineer-In-Charge by carrying out all the requisite tests (pullout test, torque test, etc) by means of specimen expansion fasteners (representative of those to be used) to demonstrate the adequacy of their strength and load carrying capacity. The cost of all such tests shall be borne by the LSTK CONTRACTOR.

23.6 Installation

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The LSTK CONTRACTOR shall install the expansion fasteners at their correct location (to suit the requirement of fixtures as shown in drawings) as per the procedure laid down by the manufacturer. Location of all holes shall be premark on the concrete surfaces and than hole drilled carefully with an electric drill to the correct recommended size and depth. Holes shall be exactly round and true to the concrete surface. Edge distance and pitch of fasteners shall be as recommended by the manufacturer. Holes may be suitably shifted with the approval of the Engineer-In-Charge in case any reinforcement bar is met with while drilling the hole in RCC structure. Necessary staging shall be provided and the LSTK CONTRACTOR shall take requisite safety precautions so as not to cause any damage to the existing structure / equipment. Any damage done while, executing the job shall be made good by the LSTK CONTRACTOR at his cost.

23.7 Protection

The exposed surfaces of expansion fasteners shall be properly covered with jute cloth so as to protect them from damage.

24.0 GROUTING

Grouting shall be as per Grouting Specifications.

25.0 PAINTING

Painting shall be as per PAINTING specifications.

26.0 MEASUREMENTS

The weight of structural steel members shall be assessed from the approved fabrication drawings and from respective Bill of Materials approved by Engineer-In-Charge. The weights of individual members shall be calculated on the basis of IS 808. No allowance in weight shall be made for rolling tolerance, welds, bolts, nuts, shims etc.

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