1.

GENERAL SPECIFICATION FOR STRUCTURAL STEEL WORK

1.1. Fabrication of Steel Structures

1.1.1. Drawings

1.1.1.1. The Contractor shall prepare fabrication drawings, erection drawings, bill of
materials, drawing office dispatch lists/shipping documents, schedule of bolts
and nuts and as built drawings. All drawing work shall be in metric system
and all writing work shall be in English.

1.1.1.2. The fabrication drawings shall show full length with all connecting members
and connections marked thereon. The fabrication drawings shall include all
the necessary blown-up details required for the correct fabrication of the
structures to meet the design requirement. These drawings shall be made in
conformity with the best modern practices and with due regard to speed and
economy in fabrication and erection. Each erection piece shall be clearly
identified by an erection mark in these drawings.

1.1.1.3. The preparation / detailing of fabrication drawing shall be complete in all

respects. In the case of bolted connections, the bolt dia, the hole dia, the
actual location of holes and the coordinating scheme with connecting /
matching elements shall be clearly indicated. As far as possible, uniformity in
the bolt dia shall be maintained where HSFG bolts are used; method of
surface preparation shall be indicated. In case of welded constructions, the
size and length of welds along the relevant weld lines should be distinctly
marked. The length specified shall be the effective length excluding end
crates. For all butt welds, details of appropriate edge preparation shall be
indicated.

1.1.1.4. Detailing of structural steel members subjected to dynamic loading shall be

so as to keep the stress concentration to a minimum. Cross welding shall be
avoided as far as practicable.

1.1.1.5. For bolted connections subjected to dynamic loading, lock nuts or spring
washers shall be used in addition to plain washers.

1.1.1.6. Erection drawings shall consist of line diagrams showing every detailed
member in position with the respective erection mark. Erection marks shall
appear on the left end of the members as detailed. All steel members shall be
erected with marks in the same relative position as shown in plan or
elevation. All loose members shall either be given part marks or wired on to
the main erection mark for dispatch.

1.1.1.7. The erection clearances for cleat-connected ends of member’s connection

steel to steel shall preferably not be greater than 10 mm. at each end. The
 erection clearance at ends of beams shall not be more than 20mm. at each
end but where for particular reasons greater clearance is necessary, suitably
designed seats shall be provided.

1.1.1.8. The fabrication drawings shall be prepared in such a manner that structures
are dispatched with maximum transportable lengths and work involved at
site is minimum. Steelwork shall be shop-fitted and ship-assembled as far as
practicable.

1.1.1.9. All edge preparations for welding shall conform to IS: 9595.
1.1.1.10. The Contractor shall ensure correctness & completeness of fabrication
drawings.

1.2. Material of Construction

1.2.1. All steel and other materials used for steelwork and in association with
steelwork shall conform to appropriate Indian standards. Only tested
materials shall be used unless written authority is obtained for the use of
untested materials for certain secondary structural members.

Unless otherwise specified in the drawings:

a) All rolled sections and plates up to & including 20 mm thickness shall conform
to Grade “A” as per IS: 2062
b) Plates of thickness above 20 mm and Plated structures subjected to dynamic
loading shall conform to Grade “B” as per IS: 2062
c) For High Tensile steel requirements, materials conforming to IS: 8500 or
SAIL-MA (HYA or HYB) shall be used.

1.2.2. Steel sheets shall conform to IS: 1079

1.2.3. Steel tubes for structural purpose shall conform to IS: 1161/4923 (of Grade Yst
310/355) as per design requirements.

1.2.4. Translucent sheets shall be fiberglass reinforced polyester sheets of matching profile
as per IS: 12866.

1.2.5. Colour coated sheets shall be as per appropriate standard.

1.2.6. Gutters shall be of copper bearing steel conforming to Grade “A” as per IS: 2062

1.2.7. All black bolts, nuts and locknuts shall conform to IS: 1363 and IS: 1364 (for precision
and semi precision hexagonal bolts) of property class 6.4 unless otherwise specified.
Washers shall conform to IS: 6610

1.2.8. All tapered washer shall be as per IS: 5372 for channels, and IS: 5374 for Joists Spring
washers shall conform to IS: 3063
1.2.9. 1.2.9 All HSFG bolts shall conform to IS: 3757. Assembly of joints using HSFG bolts
shall conform to IS: 4000. Nuts and washers of HSFG bolts shall be as per IS: 6623 &
IS: 6649 respectively.

1.2.10. Covered electrodes for arc welding shall conform to IS: 814. Coding of electrodes
shall be as follows:
a) ER421 ‘C’ X for mild steel of Grade ‘A’ and Grade ‘B’ as per IS: 2062
b) EB 542 ‘C’ H3X for Mild steel of Grade ‘B’ as per IS: 2062 for dynamically
loaded
structures (arising out of crane, vibratory screen, equipment’s etc.) ‘C’ is
the
value of the current as recommended by the electrode manufacturer.

1.2.11. Certified mill test reports of materials used in the work shall be made available for
inspection by the Engineer-In-charge upon request.

1.2.12. All materials shall be straight and if necessary before being worked shall be
straightened and /or flattened by pressure including de-coiling of plates unless
required to be of curvilinear form and shall be free from twists.

1.2.13. The MS / GI gratings shall be electro-forged and shall be of approved brand and
manufacturer unless otherwise agreed to by the Engineer-In-charge. The type of
grating selected shall be based on the loading in the area in which the grating is
provided and shall be subject to approval of Engineer-In-charge.

1.3. Material Preparation

1.3.1. Cut edges shall be finished smooth by grinding or machining wherever necessary.
Sufficient allowance (3 mm to 5 mm) should be kept in the items in case machining is
necessary.

1.3.2. Cutting may be effected by gas cutting, shearing, cropping or sawing. In gas cutting of
high tensile steel, special care is to be taken to leave sufficient metal to be removed
by machining so that all metal that has been hardened by flame is removed.

1.3.3. Sufficient shrinkage allowance (@1mm/M) shall be kept wherever heavy welding is
involved.
1.3.4. Straightening and bending shall be done in cold condition as far as practicable.

1.3.5. If required, straightening and bending may be done by application of heat between
900ºC and 1100ºC. Cooling down of the heated item shall be done slowly.

1.4. Drilling and Punching of Holes

1.4.1. Drilling and punching of holes for bolts shall be done as per clause no. 11.4.4 of IS:
800:1984, unless otherwise specified by the Owner.
1.4.2. Drifting of holes for bolts during assembly shall not cause enlargement of holes
beyond permissible limit or damage the metal.

1.4.3. Holes of bolted connection should match well to permit easy entry of bolts. Gross
mismatch of holes shall be avoided.

1.4.4. Permissible deviation in holes for mild steel bolts of normal accuracy and high
strength bolts are given in the ANNEXURE-A.

1.5. Assembly for Fabrication

1.5.1. Fabrication of all structural steel work shall be in accordance with IS: 800-1984 and
in conformity with various clauses of this specification, unless otherwise specified in
the drawings.

1.5.2. Fabrication of structures shall preferably be taken up as per the sequence of

erection.

1.5.3. All erection units shall bear erection mark no. and reference drg. No. at a prominent
location on the structures for easy identification at site.

1.5.4. Fabricated structures shall conform to tolerance as specified in this standard and in
IS: 7215-1974. In case of contradiction, tolerances specified in this standard shall
prevail.

1.5.5. All the components of structures shall be free from twist, bend, damage etc.

1.5.6. Assembly of structures shall be carried out by using suitable jigs and fixtures in order
to obviate distortion during welding.

1.5.7. Cutting of items specially for truss, bracing, bunker, hopper, galleries surge girder,
portal etc., shall be done only after checking of sizes as per layout.

1.5.8. Surface, wherever machining is specified, shall be either planed or milled or ground
to ensure maximum contact.

1.5.9. If end-milling or machining is planned after the assembly is over, sufficient

allowance(5 mm to 15 mm) shall be kept in the items where milling/machining is to
be done.

1.5.10. If pre-bending of the plate is required to avoid welding distortion; it shall be done in
cold condition.

1.5.11. Sufficient trail assembly of fabricated components (dispatch elements) shall be

carried out in the fabrication works to control the accuracy of workmanship.
1.5.12. Where necessary, washers shall be tapered or otherwise suitably shaped to give the
heads of nuts and bolts satisfactory bearing.

1.5.13. The threaded portion of each bolt shall project through the nut at least by one
thread.

1.5.14. Tolerance of assembled components of structures are given in IS: 7215: 1924

1.5.15. Permissible deviations from designed (true) geometrical form of the dispatch
elements shall be in accordance with IS: 7215-1974.

1.6. Method of Construction

1.6.1. The method of construction shall be either by welding or by bolting limiting the site
work to the minimum possible.

1.6.2. Bolt diameter shall not be less than 16mm. except for bolts securing roof and wall
sheeting, windows, doors and stitching of thin coverings. For bolted joints, min two
bolts shall be used.

1.6.3. The size of fillet welds shall not be less than 5mm for load-bearing joints.

1.6.4. Main structural elements shall be welded continuously. Intermittent welds shall be
used only on secondary members, which are not exposed to weather or other
corrosive influence.

1.6.5. Connections and splices shall be made by welding, or by bolting with high tensile
Turned and fitted bolts. Black bolts shall be used in connections and attachments of
secondary members such as purlins, wall girts, etc. Bolts shall be prevented from
Loosening by means of lock nuts, single coil spring washers or similar devices.

1.6.6. 1.6.6 Method of splicing shall be similar to the method of construction adopted for
structures. All splices shall be full-strength splice unless exception is specified.

1.6.7. Roof and wall sheets shall be fixed to purlins and wall girts by stainless steel top
speed screws/galvanized J-hook bolts, each complete with neoprene and stainless
steel /galvanized washers. The connections shall ensure water tightness into the
buildings. The spacing of these screws/bolts shall be sufficient to prevent uplift of
sheets by suction. The roof and wall sheets shall be stitched together at their edges
by using studs, rivets or screws. The end and side overlaps of sheeting shall be
sufficient to prevent ingress of rainwater. End lap shall not be less than 75mm and
side lap shall not be less than one a half corrugation for GCS sheets. For troughed
Aluminum sheets manufacturer’s recommendations shall be followed.

1.7. Structural Steel Connection

1.7.1. The Contractor shall be responsible for the design and the detailing of all
connections. The design of connections shall provide for adequate strength for the
transfer of force in the structural elements indicated on the design drawings. For
purposes of detailing of connections, the allowable stresses in material, bolts and
welds shall be as per IS: 800 and IS: 816 or as specified in the design drawings.

1.7.2. For all full strength butt welding of plates and sections thicker than or equal to
10mm, edge preparation shall be done and got approved by the Engineer-In-charge

1.7.3. Two numbers of washers shall be used for all bolted connections, one washer
bearing against the head and other bearing against the nut.

1.7.4. The magnitude of forces shown on design drawings shall be used at face values with
no reductions for connections.

1.7.5. If extra joints are to be provided in column, crane girder etc, prior approval on the
same
shall be obtained from the Engineer-In-charge. However, as general guidance, the
following is suggested:
a) Splice joint on column and crane girder shall be of full strength but weld, and,
wherever possible, shall be located at the section of minimum or substantially
lesser stress.
b) Splice joints of web and flange should be sufficiently staggered in position.

1.7.6. All penetration for piping, conduit, cable trays, etc., through grating or plate flooring
shall be cut and suitably banded in the field, except when such penetrations are
dimensioned in the drawings in which case they shall be shop cut and banded.

1.8. Fabrication

1.8.1. Fabrication of all structural steelwork shall be in accordance with IS: 800 or their
equivalent foreign national standard of the country of origin of supply unless
otherwise specified, and in conformity with various clauses of the Technical
Specification.

1.8.2. Wherever practicable and wherever perfect matching of parts is required at site,
members shall be shop assembled before dispatch to minimize site work. Parts not
completely assembled in the shop shall be secured, to the extent possible, to prevent
damage during dispatch.

1.8.3. All pieces shall be properly identified and bundled for transportation to work site.
Care shall be exercised in the delivery, handling and storage of material to ensure
that material is not damaged in any manner. Materials shall be kept free of dirt,
grease and foreign matter and shall be protected from corrosion. All materials shall
be stored properly on skids above the ground which shall be kept clean and properly
drained. Girders and beams shall be placed upright and stored. Long members such
 as columns and chord members shall be supported on skids spaced near enough to
prevent damage due to deflection.

1.8.4. Bolts shall be furnished according to bolt lists showing the location of their use and
additional bolts shall be supplied to cover wastage.

1.8.5. All fabricated pieces shall bear erection mark numbers painted/punched according to
appropriate erection and shop drawings at a prominent location on the structure for
easy identification.

1.8.6. All workmanship shall be in accordance with the best practice in modern structural
shops. Greatest accuracy shall be achieved in the manufacture of every part of the
work and all identical parts shall be strictly interchangeable.

1.8.7. Shearing or flame cutting may be used at the Contractor’s option provided that a
mechanically controlled cutting torch is used for flame cutting and that the resulting
edges are clean and straight.

1.8.8. Unless clean square and true to shape all flame cut edges shall be planed/cleaned by
chipping or grinding. Where machine flame cutting is permitted of high tensile steel,
special care shall be taken to leave sufficient margin and all flame hardened material
shall be removed by machining/edge grinding.

1.8.9. Wherever shearing is used for cutting to size, sheared members shall be free from
distortions at sheared edge.

1.8.10. The ends of all girder stiffeners shall be in contact with the compression flange and
shall be planed or ground to fit tightly against flange plates unless otherwise stated
on the drawings. Care shall be taken to ensure full bearing of the stiffeners at the
supports by machining the contact surfaces of both bearing stiffeners and bearing
plates. The ends shall not be drawn or caulked.

1.8.11. Column splices and butt joints of struts and compression members depending on
contact for stress transmission shall be accurately machined and close butted over
the whole section with a clearance not exceeding 0.1mm locally at any place.

1.8.12. In column cap and bases, the ends of shafts, should be accurately machined so that
the parts connected butt over the entire surface of contact. Care should be taken so
that these connecting members are fixed with such accuracy that they are not
reduced in thickness by machining by more than 1.0mm. On secondary members,
where sufficient gussets and welds are provided to transmit the entire loading. The
column ends may not be machined subject to the approval of the Engineer-In-charge.

1.8.13. Holes for permanent black bolts shall not be more than 1.5mm larger than the
nominal diameter of the back bolts unless specified otherwise. All holes for turned
and fitted bolts shall be sub punched or drilled and reamed at site under assembly of
connected parts to a tolerance of +.3mm unless specified otherwise. Holes in purlins,
 side-sheeting runners, packing plates and lacing bars may be punched full size. Holes
in light framing with the exception of joint holes may be punched full size. All
punching and sub-punching shall be clean and accurate and all drilling free from
burrs. In block/batch drilling, parts shall be separated after drilling and burrs
removed. No hole shall be made by gas cutting process.

1.8.14. The component parts shall be so assembled that they are neither twisted not
otherwise damaged and specified cambers, if any, shall be provided. No drifting of
hole shall be permitted except to draw the parts together. Drifts used shall not be
larger than the nominal diameter of the bolt. Drifting done during assembling shall
not distort the metal or enlarge the holes. Sufficient trial assembly shall be carried
out in the fabrication works to prove the accuracy of workmanship and the number
of such trials required shall be at inspector’s discretion.

1.8.15. Where necessary, washers shall be tapered or otherwise suitably shaped to give the
heads and nuts of bolts a satisfactory bearing. The threaded portion of each bolt
shall project through the nut by at least one thread.

1.8.16. In all cases where the full bearing area of the bolt is to be developed, the bolt shall be
provided with a washer of sufficient thickness, under the nut so as to avoid any
threaded portion of the bolt being within the thickness of the parts bolted together.
Column bases and caps, shall be in one solid piece, and except when cut from plates
with true surfaces, shall be accurately machined over the bearing surfaces, and shall
be in effective contact over the whole area of the machine end of the stanchion.

1.8.17. Each piece shall be distinctly marked before delivery in accordance with an approved
marking diagram and shall bear such other marks as well to facilitate erection. For
easy identification at site a small distinguishing mark for each building shall be
painted at each end of every member before dispatch from fabrication shop. The
fabricated steel work shall be dispatched in sequence as per agreed program and for
such portion as may be found convenient for erection or as ordered by the Engineer-
In-charge.

1.8.18. The Contractor shall provide suitable packing wherever necessary to guard against
damage during handling and transportation to site. All fabricated parts shall be
adequately braced to prevent damage during transit.

1.8.19. The tolerance for fabrication of steel structures shall generally conform to IS: 7215
and to suit the technological requirements as specified by the equipment supplier.

1.8.20. Any fabrication work which is considered not to be in keeping with the Technical
Specification forming the Contract, or in absence of Technical Specification with
recognized good practice, shall be rectified/replaced/corrected at the Contractor’s
expense as directed by the Engineer-In-charge. Site fabrication work shall also
conform to all specifications, stipulations, terms and conditions applicable for shop
welded structures as mentioned above.
1.9. Dispatch Instructions

1.9.1. Each dispatch able structure shall bear mark no. along with reference drawing
number at two prominent locations (e.g. on flange and bottom of base plate of a
column).

1.9.2. “As built” drawing shall be prepared after fabrication is completed to indicate
additions/alterations made during the process of fabrication.

1.9.3. Control assembly of important structures shall be done in the shop floor before
dispatch to avoid mismatching. For all such important structures, match marking shall
be given at the control assembly stage in the shop floor as such match markings shall
be made clearly visible while assembling the structures at site.

1.9.4. Centre lines of column flanges and both sides of web shall be punched preferably at
top and bottom to facilitate alignment after erection.

1.10. Erection of Steel Structure

1.10.1. Scope

The scope of work under erection includes in addition to provision of erection and transport
equipment, tools and tackles, consumables, materials labour and supervision the following.

a. Storing and stacking at site of erection of all fabricated structural components/

units/ assemblers at the time of erection.

b. Transportation at the site of structures.

c. Receiving at site of structures including site handling /movement, unloading,

storing at site of erection of technological structures such as bunkers and the
related structure.

d. All minor rectification/ modification such as :

i) Removal of bends, kinks, twists etc. for parts damaged during transportation
and handling.
ii) Cutting, chipping, filling, grinding etc. if required for preparation and
finishing of site connections.
iii) Reaming for use of next higher size bolt for holes which do not register or
which are damaged.
iv) Welding of connections in place of bolting for which holes are either not
drilled at all or wrongly drilled during fabrication.

e. Other rectification work such as :

 i) Re-fabrication of parts damaged during fabrication beyond repair during
transportation and handling or incorrectly fabricated.
ii) Fabrication of parts omitted during fabrication by oversight or subsequently
found necessary.
iii) Plug welding and re-drilling of holes which do not register and which cannot
be reamed for use of next higher size bolt.
iv) Drilling of holes which are either not drilled at all or are drilled at incorrect
position during fabrication.

f. Fabrication of minor items/ missing items or such important items as directed by

the Engineer-In-charge.

g. Assembly at site of steel structural components wherever required including

temporary supports and staging.

h. Making arrangements for and providing all facilities for conducting ultrasonic X-
rays or gamma ray tests on welds, getting the tests conducted, reports and
interpretation.

i. Rectifying at site damaged portions of shop primer by cleaning and touch-up

paint.

j. Erection of structures including making connections by bolts/high strength

friction grip bolts/welding.

k. Alignment of all structures true to line level plumb and dimensions within
specified limits of tolerances as per IS : 12843 “Tolerance for Erection of Steel
Structures”

l. Application of second coat of primer paint and two coats of finishing paint at site
after erection.
m. Grouting of all columns bases after proper alignment of columns and only after
obtaining clearance from Engineer-In-charge.

n. Supply of labour in sufficient numbers where necessary, as directed by the

Engineer-In-charge.

o. Conducting preliminary acceptance and final acceptance tests.

p. Preparation of as built drawings, preparing of sketches/drawings to suit field

engineering decisions, availability of material, convenience of fabrication,
transportation and erection and changes during fabrication and erection.

All such works are subject to approval by the Engineer-In-charge.

1.10.2. Erection Drawings

1.11.1 The erection drawings prepared by the Contractor and any approved arrangement
drawings specifications or instructions accompanying them shall be followed in
erection of structures and miscellaneous connected items throughout the project.

1.10.3. Storing and handling

1.10.3.1. The fabricated materials on receipt at site shall be carefully unloaded, examined
for defects, checked, stored out for each building and stacked securely on skids
above level ground which shall be kept and properly drained. Girders and beams
shall be placed upright and stored. Long members, such as columns and chord
members shall be supported on skids spaced near enough to prevent damage
from defection.

1.10.3.2. The fabricated materials shall be verified with respect to markings on the
marking plan or shipping list which shall be supplied by the Contractor.

1.10.3.3. Any material found damaged or defective shall be stacked separately and the
damaged or defective portions shall be painted in distinct colour for
identification. Such materials shall be dealt with as ordered by the Engineer-In-
charge.

1.10.3.4. The handling and storing of the component parts of a structure shall involve the
use of materials and applications not likely to produce injury by twisting, bending
or otherwise deforming the structures. No member slightly bent or twisted shall
be put in place until the defects are corrected. Members seriously damaged in
handling shall be rejected.

1.11. Defects in material fabrication

1.11.1. All materials shall be straight unless required to be of curvilinear from and shall be
free from twists. All cold straightening shall be done by pressure only.

1.11.2. During assembly and during erection of the units to position, the Contractor shall
compare the structure with drawings to ensure that there are no fabrication
omissions or errors. Should any omission or defect be found the same shall be
brought to the notice of the Engineer-In-charge who will issue necessary instructions
for the rectification.

1.11.3. Setting out

1.11.3.1. The Contractor shall prepare geodetic survey of all embedded parts and holding
down bolts and submit the same to Engineer-In-charge. The Contractor shall
inform
 a) The Engineer-In-charge about any discrepancy with approved design drawings
well in advance of erection and if necessary shall make necessary adjustments
at site during fabrication of structures.

1.11.3.2. The Contractor shall assume, full responsibility for the free and correct setting
out of all steel work and erection correctly in accordance with position,
alignment, dimensions and levels shown on the approved drawings and plumbing
vertical members. Particular care shall be taken to ensure free expansion and
contraction wherever provided. Notwithstanding any assistance rendered to the
Contractor by the Engineer-In-charge if at any time during the progress of the
work, any error should appear or arise therein, on being required to do so, the
Contractor at his own cost shall remove and amend the work to the satisfaction
of the Engineer-In charge.

1.11.4. Assembly and Erection

1.11.4.1. Before starting erection, the Contractor shall submit to the Engineer-In-charge for
his approval the method he propose to follow and the number of types of
equipment and temporary works he propose to use for the erection.

1.11.4.2. The approval of drawings by the Engineer-In-charge will not relieve the Contractor
from the basic approach to design as regards the loads which the erection
equipment and temporary work shall be called upon to carry and support.
Adequate allowance and provisions shall be made for lateral forces and wind
loads.

1.11.4.3. If in the opinion of the Engineer-In-charge, the tools, tackles, plant and
equipment, instruments, apparatus etc. arranged by the Contractor are not
sufficient or are inadequate for the fulfillment of the contractual obligations of the
Contractor within the stipulated period, the Engineer-In-charge will have the right
to order the Contractor and the Contractor shall comply with the order to bring
/arrange such additional tools, tackles, plant and equipment instruments,
apparatus etc. to the site and employ the same to complete the work in time. All
charges in connection thereof shall be borne by the Contractor.

1.11.4.4. Proper consideration shall be given to the following items during erection.

i) Frame of building to be true and plumb.

ii) Temporary guying and bracing shall be used to align the framing during
erection if required.
iii) Temporary bracing may be required to sustain forces due to erection loads
and equipment. Erected parts of the structures shall be made stable during
all stages of erection. The stability of structure subjected to the action of
wind, dead weight and erection forces shall be attained by observing
specified sequence of erection of vertical and horizontal structural members
and by installing permanent and temporary bracings.
 iv) Erection members shall be held securely in place by bolts to take care of
dead load, wind load and erection load.
v) Free expansion and contraction wherever provided.
vi) No final bolting or welding of joints shall be done until the structure has
been properly aligned and consent obtained from Engineer-In-charge.
vii) Erection tools and machinery shall be suitable capacity for handling the
materials furnished and must be in safe operating conditions at all times to
avoid danger to materials and personnel.
viii) In positioning beams, columns or other steel members the use of steel
sledges shall not be permitted.
ix) The Contractor shall report all failures of the fabricated steel to fit together
properly to the Engineer-In-charge and shall obtain approval prior to taking
corrective measures.
x) Steel members shall not be allowed to fall or be subject to shock or impact
due to other members being swung into position or for any other cause.
xi) All exposed bolts holes not required shall be plugged.

1.11.4.5. Erection shall be carried out according to the best modern practices and as laid
down in the IS : 800-1984 and other relevant standards referred to therein and
according to this erection specification together with approved erection drawings
and technical specifications.

1.11.4.6. The Contractor shall design, manufacture, erect and provide false work, staging,
temporary supports etc. required for safe and accurate erection of structural
steel work and shall be fully responsible for the adequacy of the same.

1.11.4.7. The Contractor shall, if so required by the Engineer-In-charge, get his drawings,
erection schemes and designs for such false work, staging etc. approved by the
Engineer-In-charge, but such approval by the Engineer-In-charge shall not relive
the Contractor of any of his responsibilities for the safety of such works. As far as
possible, assemblies of structures shall be made on the ground itself.

1.11.4.8. The Contractor shall provide adequate supervision at all stages of the work and
examine each portion of the work for accuracy before commencing the erection
of the next structural member. The Contractor shall also provide facilities such as
adequate temporary access ladders, tools and tackles, instruments etc.
satisfactory to Engineer-In-charge / Consultant for his inspection at any stage
during erection.

1.11.4.9. Instrumental checking for correctness of initial setting out of structures and
adjustment shall be carried out in sequence at different stages as determined by
design as against checking and adjustment of alignment in one stage after
completion of entire erection. The final leveling and alignment shall be carried
out immediately after completion of each section of a building or when called for
by the Engineer-In-charge.

1.11.4.10.All structural members shall be erected with erection marks in the same relative
 a) Position as shown in the appropriate erection and shop drawings.

1.12. Field Connections

1.12.1. The holes of erection joints required to be machine bolted shall be filled with
temporary bolts and plugs after mounting the structures. The number of bolts and
plugs shall be determined by design but shall not be less than 50% of the total
number of holes. In joints where the number of holes is equal to 5 or less, not less
than 3 holes shall be filled. The number of plug shall be about 20% of the holes filled.

1.12.2. The number of washers on permanent bolts shall not be more than two (and not less
than one) for nut and one for the bolt head. Wooden rams or mallet shall be used for
forcing members into position in order to protect the metal from injury and chipped
edges shall be finished with a file and all short corner and hammered rough faces
shall be rounded off. Chipping with the use of sledge hammer shall only be permitted
in exceptional cases and shall be done without resulting in fractured edges.

1.12.3. Where bolting is specified on the drawings, the bolts shall be tightened to the
maximum limit. The threaded portion of each bolt shall project through the nut by at
least one thread. Tapered washers shall be provided for all heads and nuts having
bearing on beveled surfaces. Use of special bolts, such as high strength friction grip
bolts, shall be according to the relevant Indian or other recognized standards and
shall be subject to the prior approval of the Engineer-In-charge before use.

1.12.4. Spring washers or lock nuts shall be provided as specified in the design/ shop
drawings. All machine fitted bolts shall be perfectly tight and the ends shall be
checked to prevent nuts from becoming loose. No unfitted holes shall be left in any
part of the structures. All field assembly and welding shall be executed in accordance
with the requirements for shop fabrication. Where the steel has been delivered
painted, the paint shall be removed before field welding for a distance of at least 50
mm on either side of the joints.

1.12.5. Erection bolts shall be retained in position permanently even after site welding.

1.13. Assembly by high strength friction grip bolts

1.13.1. The mating surface shall be absolutely free from grease, lubricant, dust, rust etc. and
shall be thoroughly cleaned before assembly. The preparation of mating surface shall
be done as specified in the design drawings.

1.13.2. Nuts shall be tightened up to the specified torque with the help of torque wrench or
by half turn method with the help of pneumatic wrench lever. Torque value has to
be specified in design/ fabrication drawings itself. The direction of tightening of the
nuts shall be from the middle towards the periphery of the joint. The bolt head, nuts
and edges of the mating surface shall be sealed with a coat of paint to obviate entry
of moisture. As far as possible, the diameter of bolts and nature of mating
 a) Surface preparation shall be kept uniform to have specified unique torque.

1.14. Bedding and grouting

1.14.1. Base plate shall be set to elevations shown in the drawings supported and aligned
using steel wedges and shims or any other approved method. The supply of wedges,
shims and any other materials for alignment shall be the responsibility of the
Contractor as part of his work. Plates shall be leveled properly positioned and the
anchor bolts properly tightened. The bedding/grouting shall not be carried out until
a sufficient number of columns have been properly aligned, plumbed and sufficient
girders, beams, trusses and bracing to the satisfaction of the Engineer-In-charge.

1.14.2. Grouting shall be done before casting of elevated RCC floor, if equipment’s
contributing to the loading on columns are placed moving equipment shall be tested
and no trial run of any equipment before grouting has been done and cured to the
satisfaction of the Engineer-In-charge.

1.14.3. Grouting shall be minimum M-25 grade or one grade higher that the concrete with
10 mm and below graded coarse aggregate. Ready mixed free-flow grout from
recognized manufacturer as approved by the Engineer-In-charge shall be used with
pressure grouting as technique to ensure up of all void spaces underneath the base
plate. Manufacturer’s recommendation/instruction shall be followed for proper
application of grout materials.

1.14.4. The Contractor shall inform the Engineer-In-charge when the work is ready for
grouting for their verification. The Contractor shall be responsible for the final
vertical and horizontal alignment of all the base plates.

1.15. Painting after erection.

The painting shall be as per painting specifications and instructions.

1.16. Acceptance of work

1.16.1. Acceptance of erected steel structures shall be either after erection of the whole
building or in blocks. Intermediate acceptance certificate will be given in the
following:
i) Any steel work or part thereof embedded in concrete.
ii) Steel structures which are to be covered in the process of further work.

1.16.2. The following documents shall be prepared and produced at the time of acceptance
of erected steel structures:
i) Documents showing approved deviations made during erection of work.
ii) Documents showing acceptance of embedded structures
iii) Certificate/documents on control checking and tests of nuts and welds.
iv) Data and results of geodetic measurement while checking of structures.
v) Copies of ‘As built Drawings’ showing thereon all alterations.