SCOPE
OF WORK
The
scope of structural steel erection shall include the following as applicable to
Contractor's work included in Book II refers to "Summary of Work" and
in Book IIIA refers to "General Civil and Architectural Design
Requirements'.
Unloading, storing, protecting,
removing from storage and erecting the following:
Structural steel.
Gallery and auxiliary steel.
Performing all bolting work for field
connections using high strength.
Furnishing welding electrodes and
performing welding for field welded joints that are included in the Work.
Furnishing, and installing anchor bolts
and anchor bolt sleeves into concrete foundations.
Laying out and verifying lines and
grades as specified in here.
Grouting of column base plates.
CODES AND STANDARDS
The Contractor shall comply with the requirements of Book II
refers to "Codes and Standards".
The codes and standards of the following organizations
extracted from the Book II refers to "Codes and Standards" are
specifically applicable to the design, manufacture and testing of the work
included in this Specification:
AISC ………… American Institute of Steel
Construction
ASTM ………… American Society for Testing and
Materials
AWS …………
American Welding Society
SUBMITTALS
ERECTION DRAWINGS
Erection and detail drawings for all parts of the work shall
be prepared by the structural steel fabricator and coordinated with the erector
to maximize shop fabrication and to minimize field fabrication as far as
practical. These drawings shall also include erection and detail drawings for
welding new steel to existing steel.
REPORTS
Copies of welding qualification reports, quality control
reports, and other reports as specified or required, shall be furnished by
Contractor to the Owner, during the course of the work, or upon completion of
the work.
FIELD
REPRESENTATIVE
The fabricator shall furnish a field representative to
assistance in the coordination of the erection of the erection work at the site
full time.
MATERIALS
WELDING ELECTRODES
Welding electrodes used for the Work
shall conform to the applicable requirements of specification welding in steel
structures.
EXPANSION ANCHORS
Expansion anchors shall conform to the
requirements of Specification Concrete Expansion Anchor work and hall receive
prior approval of the Owner.
PERFORMANCE
GENERAL PROVISIONS
Erection of structural steel shall
conform to all requirements of the AISC Manual of Steel Construction (latest
edition) and the following:
Lines and Grades
The Contractor shall lay out lines and
grades from existing base lines and bench marks on the property, and shall be
fully responsible for the correctness of these lines and grades and for proper
execution of the work.
The Owner reserves the right to verify the correctness of
these lines and grades during the progress of the work. This verification by
the Owner will not relieve the Contractor of any responsibility for the work.
The Contractor shall preserve and
maintain all benchmarks and reference points established. Should the Contractor
during execution of the work destroy or remove any benchmarks and/or reference
points established by the Owner, the cost for reestablishing these benchmarks
and/or reference points will be charged to the Contractor.
Erection Tolerances
Steel work shall be set accurately to
the established lines and grades and shall be plumbed and leveled such that the
deviations in all completed work are within the tolerance limits and meet the
requirements, as specified in the AISC Code of Standard Practice and this
specification.
Column base plates shall be set at the
specified elevations within the tolerance of ± 1.5 mm and shall be leveled
within the same tolerance.
Fitting
Members and Details
Members and details shall be fitted into place by methods
that will not injure the materials. Contractor shall replace any materials
unduly injured, at Contractor's expense. Heating of anchor bolts in the field
for bending or other purpose, and welding of ASTM A193 anchor bolts shall not
be permitted.
Column Splices
In a column contact joint, the gap between column-milled
surfaces not exceeding 0.8 mm will be accepted. If the gap exceeds 0.8 mm, but
is less than 6 mm, it shall be packed out with no tapered steel shims. The
shims shall be mild steel regardless of the column material. Gaps of 6 mm or
more shall be reported to the Owner.
Misfits
Attention
is specifically directed to the requirements of the. AISC Code of Standard
Practice and Quality Criteria and Inspection Standards, that correction of
minor misfits and a reasonable amount of cutting and reaming are considered a
part of erection.
However, any errors in shop work which prevent proper field
assembly and fit up of parts shall be reported, as soon as they are discovered,
to the Owner as well as to the structural
steel fabricator, so that the fabricator may either correct the errors or make
substitution to be used.
The allowable limits for reaming the connection bolt holes
for fitting in the field shall conform to
the requirements of the AISC Quality Criteria and Inspection Standards. If fitting of bolts during erection in the
field cannot be obtained
by reaming the fabricated boltholes within these limits, it is considered that there are errors in
fabrication, and these errors shall be rectified as mentioned before.
Correction of misaligned boltholes by
the use of flame cutting is not permitted.
Field Connections
Connections of new steel to existing
steel shall be made by welding, unless otherwise specified.
All other connections shall be made by
high strength bolting, unless otherwise specified.
Where
new steel is to be connected to existing steel, Contractor shall verify the
locations, dimensions etc. of existing steel for alignment, prior
to start of erection.
WELDING
All welding including stud welding
shall be performed in accordance with the Specification Welding in Steel
structures.
HIGH STRENGTH BOLTING
Type of Connection
FRICTION TYPE Connection, as specified in the AISC Manual
and the "Specification for Structural Joints Using ASTM A325 Bolts"
shall be used for all bolted connections unless otherwise indicated.
Types of Bolts
The following types of high strength
bolts shall be used unless otherwise indicated.
ASTM A325 Type 1 for
all bolt sizes.
Assembly of Joints
Method of Installation
The Turn‑of‑Nut Tightening or Calibrated Wrench Tightening
method, as specified in the AISC "Specification for Structural Joints
Using ASTM A325 Bolts," shall be used.
Bolt and Nut Assembly
All
nuts shall be fully engaged with a minimum of 6 mm projection of the installed
bolt beyond the nut. The threaded part of the installed bolt shall not be in
the shear plane. Reuse of bolts as specified in the AISC Specification for
Structural Joints will not be permitted.
Fairing Up
The
Contractor shall fair up the holes in each connection with enough pins to
maintain the dimensions and plumb ness of the structure. These pins shall
remain in place until all bolts in the balance of the holes have been
tightened.
Washers
a.For an A325 bolt, a hardened flat
washer shall be used under the bolt head or under the nut, whichever is to be
turned in tightening.
b.Beveled washers shall be used as
specified in the AISC Specification for Structural Joints Using A325 Bolts.
Location of Bolt Heads
a Columns: On outside faces of flanges.
b. Beams and Girders:
On upper sides of flanges.
INSTALLATION OF EXPANSION ANCHORS
Shall conform to the requirements of Specification Concrete
Expansion Anchor work.
ERECTION DETAILS
Column Stiffener Plates
Column stiffener plates at connection joints with beams and
girders may be shipped loose by fabricator and shall be installed by the
Contractor.
Curb Angles and Guard Plates
All curb angles and guard plates are connected to structural
steel in the shop.
For adjoining guard
plates in continuous runs or at corners, the Contractor shall tack weld the
ends together at the top.
Trolley Beams
The
Contractor shall carefully align the bottom flanges of trolley beams at splices
so that the upper surface of bottom flanges provides a smooth passage for
travel of the trolley passing each splice.
Girt System
The girt system shall include
horizontal girt, door, window and louver framing,
and other vertical members attached to girt, parapet framing, sag rods, etc.
The
girt system shall be erected within the tolerances specified as mentioned
before.
Sequence of Erection
Girt shall be erected in vertical sequence with the erection
of structural steel to provide wall bays with girt completed from ground to
roof. This will permit erection of siding in these bays without girt erection
being carried on above siding erection at the same time.
Erection Around Door, Window and Louver
Openings
Girt around such openings shall be erected in accordance
with the following requirements:
a.All corners of openings formed by the
junctions of horizontal girt and vertical members of the girt system shall be
absolutely square.
b.Vertical and horizontal dimensions of
openings shall each be within an overall tolerance of ± 1.50
mm for doors, ± 6 mm for windows, and + 6 mm to 0 mm for louvers.
c.Junctions of horizontal girt and
vertical members at the head and sill of door openings will be detailed with
end clearances not exceeding 6 mm nor less than 3 mm, and will be arranged for
field welding closure of these junctions by the Contractor.
Stainless Clad Steel
General Processes
The installation of stainless clad steel shall conform to
applicable requirements of the manufacturer for installation, welding,
handling, protecting, etc. of that steel. Prior to installation, Contractor
shall also consult with the manufacturer to insure the best possible
installation of the material for the intended service.
Welding
a.The Contractor shall use stainless
steel electrodes only, as specified in Welding in Steel structures or as
recommended by the stainless steel manufacture, for all welding on the
stainless clad side of the material. He shall perform all welding operations so
as to reduce to a minimum, or completely eliminate, any weld spatter on the
stainle3s clad side. Antis patter compound shall be used along both edges of welded
joints, on the stainless clad side, to permit easier removal of any spatter
that does occur.
b.Welds on the stainless clad side
shall be reasonably smooth and shall blend smoothly into the adjacent metal;
slight undulations in the length of welds will be acceptable, but all pits,
crevices and other sharp discontinuities shall be corrected by the use of
additional weld metal (if required) and by grinding to provide satisfactory
welds.
Special Precautions
a.Do not attach any temporary materials, such as handles of lifting
lugs, etc., to the stainless clad side of the material.
b.Any scratches, gouges, or damages to
stainless clad surfaces shall be satisfactorily repaired by the Contractor at
his own expense. Fill gouges and deep scratches with weld metal as specified
for welding of stainless clad steel and grind and hand buff smooth.
Carefully remove weld spatter or other
deposits on the surfaces flush with the surfaces and hand buff these areas
smooth. Also remove discolorations, etc., using cleaning solutions and methods
recommended by the manufacturer of the stainless clad steel.
c.All precautions shall be taken to
provide ductile austenitic weld.
Temporary Shoring and Bracing
The Contractor shall be responsible for determining what temporary
shoring and bracing must be provided to support loads to which the work may be
subjected, including construction equipment arid the operation of such equipment.
The Contractor shall be responsible for the adequacy and safety of such shoring
and bracing.
FIELD CLEANING AND PAINTING
After erection is
completed, Contractor shall clean and field touch up and field finish paint all
structural steel, gallery steel and surge bins etc. in accordance with the
requirements of Field finish painting unless otherwise indicated.
INSPECTIONS AND EXAMINATION
GENERAL PROVISIONS
This
work is subject to inspection and examination by an independent testing
laboratory at the project site, for full compliance with all requirements of this specification, the
contract and Contractor's design drawings.
The Contractor shall
retain and pay for the services of a testing laboratory, personnel or
inspector(s) to perform this inspection and examination work.
The Contractor shall
provide, and pay for all rigging required for the work and for all personnel required to assist the
inspector(s).
The Contractor shall furnish and
install the tension-calibrating device. The device furnished shall bear a
certification as to the accuracy of the device. Such certification shall be dated not more than 30 days prior to the first actual use of the device for inspection of
the work.
INSPECTIONS AND EXAMINATION OF WELDING
Shall be as specified in Specification
Welding in Steel structures.
INSPECTION OF HIGH STRENGTH BOLTING
This
inspection shall be performed in accordance, with the requirements of Section 5 of the AISC Specification
for Structural Joints using ASTM A325 Bolts, and will include the arbitration
inspection specified therein.
In each connection on the structure, approximately 10% of
the bolts will be inspected, but never less than two bolts.
QUALITY
ASSURANCE/QUALITY CONTROL (QA/QC)
Quality control shall conform to the requirements of Book II.
The quality control procedures shall include but not be
limited to the following:
‑ Material certificates
‑
Welding
‑
Non destructive testing
‑ Cleaning and painting
The quality control documentation shall
include but not be limited to the following:
‑ Material certificates
‑ Welding
‑ Field test and inspection reports.