Abu Dhabi, United Arab Emirates. STANDARD CONSTRUCTION SPECIFICATIONS (PART 2 - ROAD STRUCTURES, 2020)

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the method of erection at their own expense; the Owner will not make additional payment for such
surpluses that the Contractor uses for their own convenience.

23.3

Drawings for Steel Structures

The Contractor shall submit working drawings to the Engineer for approval. Working drawings shall
include shop drawings, erection drawings, and transportation drawings for structural steel. All
working drawings shall be made in accordance with BS EN ISO 4157-1:1999, BS EN ISO 4157-
2:1999, BS EN ISO 6284:1999, BS EN ISO 8560:1999, and BS EN ISO 9431:1999.

All welding symbols shall conform to BS EN ISO 4063:2010 and BS EN 22553:1995.

For the initial review, the Contractor shall submit six sets of such drawings. After the initial review,
the Contractor shall submit from 6 to 12 sets of working drawings for final approval, for use during
construction, and in response to any request for the drawings from the Engineer.

Working drawings shall show the following information:

•

Any changes proposed in the work

•

Details and calculations for connections not dimensioned on the plans

•

Direction of rolling of plates (where specific orientation is required)

•

Sequence of shop and field assembly tasks

•

Sequence of erection activities

•

Welding sequences and procedures

•

Locations of all butt welded splices (on a layout drawing of the entire structure)

•

Locations of any temporary supports

•

Vertical alignment of the girder at each stage of erecting the steel structure

The Contractor shall also submit substantiating camber calculations and diagrams with the working
drawings.

Working drawings shall be submitted sufficiently in advance of the start of the affected work to allow
time for the Engineer to review them and the Contractor to make necessary corrections without
delaying work. Submission time before work commences shall be proportional to the complexity of
the work, but shall never be less than six weeks.

If the Contractor orders any material or the fabrication of any material before receiving the Engineer

’s

final approval for the working drawings, they do so at their own risk.

23.3.1

Shop Drawings for Steel Structures

Shop drawings for steel structures shall give full, detailed dimensions and sizes of component parts
of the structure and details of all miscellaneous parts, such as pins, nuts, bolts, and drains.

Where plates require specific orientation, shop drawing shall clearly indicate the direction in which
plates roll.

Unless otherwise specified in the Contract documents, shop drawings shall identify every piece of
steel that will not comply with the requirements for grade 36 steel outlined in AASHTO M 270M/M
270-12 or grade 250 steel outlined in

ASTM’s

Standard Specification for Structural Steel for Bridges

(ASTM A709 / A709M

– 11).

23.3.2

Erection Drawings for Steel Structures

The  Contractor  shall  submit  drawings  that  full  illustrate  the  proposed  method  of  erection.  Such
drawings  shall  show  details  of  all  falsework  bents,  bracing,  guys,  deadmen,  lifting  devices,  and
attachments  to  the  bridge  members,  sequence  of  erection,  location  of  cranes  and  barges,  crane
capacities,  location  of  lifting  points  on  the  bridge  members,  and  weights  of  the  members.  Such
drawings  shall  be  complete  in  detail  for  all  anticipated  phases  and  conditions  during  erection.
Calculations may be required to demonstrate that factored resistances are not exceeded and that
member capacities and final geometry will be correct.

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23.3.3

Camber Diagrams for Steel Structures

The Fabricator shall provide camber diagrams to the Engineer for review. Such diagrams shall show
the camber at each panel point in the cases of trusses or arch ribs, and at the location of field splices
and fractions of span length (quarter points minimum) in the cases of continuous beam and girders
or rigid frames. Camber diagram shall show calculated cambers to be used in preassembly of the
structure in accordance with Section 23.6.6.

23.3.4

Transportation Drawings for Steel Structures

If  required,  transportation  drawings  shall  be  furnished  for  approval.  All  support  points,  tie-downs,
temporary  stiffening  trusses  or  beams,  and  any  other  details  needed  to  support  and  brace  the
member shall be shown. The Contractor shall provide calculation sheets showing the dead load plus
impact stresses induced by the loading and transportation procedure.  Impact stresses to be used
shall  be  of  at  least  two  hundred  percent  (200%)  of  the  dead  load  stress.  Total  load  to  be  used,
including impact, shall not be less than three hundred percent (300%) of the dead load.

All members, both straight and curved, shall be shipped and stored in their upright position.

23.4

Materials for Steel Structures

This section outlines requirements and standards for materials used in steel structures for the
Project.

23.4.1

Structural Steel

The Contractor shall furnish structural steel materials specified in the Contract documents for
highway structures in accordance with (ASTM A6 / A6M

– 12) or (BS EN 10025 Parts 1 to 6), and

AASHTO/AWS D1.5M/ D1.5:2010, Bridge Welding Code as supplemented by the AASHTO Guide
Specifications for Highway Bridge Fabrication with HPS70W Steel, 2nd Edition. For material that the
Contract documents do not indicate the ASTM specifications, the Contractor shall furnish structural
carbon steel that conforms to ASTM A709 / A709M - 11 grade 36 (Grade 250). The Contractor shall
fabricate all unpainted steel elements using steels with weathering characteristics as defined in
ASTM A709 / A709M - 11

for grades with a “W” suffix.

Structural components designated as “fracture critical” shall conform to the provisions of the
AASHTO/AWS D1.5M/D1.5:2010, Bridge Welding Code, Section 12, AASHTO/AWS Fracture
Critical Control Plan for Non-Redundant Members, in addition to the requirements of the Contract
documents.

If the Contractor cannot obtain grade 36 (or grade 250) structural carbon steel bar that conforms to
ASTM A709 / A709M - 11 for use in secondary members in structures in the quantity specified in the
Contract documents, they may use either or both of the following alternates:

•

ASTM’s Standard Specification for Steel Bars, Carbon, Hot-Wrought, Special Quality,
Mechanical Properties (ASTM A675 / A675M - 03(2009)), grade 60 (Grade 420).

•

ASTM’s Standard Specification for Steel Bars, Carbon, Merchant Quality, Mechanical
Properties (ASTM A663 / A663M

– 12), grade 60 (Grade 420).

The Contractor shall ensure that girder flange plates, girder web plates, flange splice plates, hanger
bars, links, rolled beams, flange cover plates, and plates and angles connecting floor beams to
girders conform to zone 2 toughness requirements for longitudinal Charpy V-Notch tests specified
in AASHTO M 270M/M 270-12 (ASTM A709 / A709M - 11). The Contractor shall sample and test
according to

ASTM’s

Standard Specification for Sampling Procedure for Impact Testing of Structural

Steel

(ASTM A673 / A673M - 07(2012)) and use the (H) frequency of testing.

The Contractor shall obtain structural steel and miscellaneous metal components and products for
use on the Project from a Fabricator approved by the Owner with Accepted Quality Control Programs
for Metal Fabricators. This Fabricator shall also be certified by the AISC Quality Certification Program
with the following modifications to the AISC categories:

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•

Standard for Steel Building Structures

- Required for miscellaneous components or as

approved by the Engineer.

•

Simple Steel Bridge Structures

- Required for bolted highway sign, lighting and traffic

structures fabrication, bridge components such as cross-frames and diaphragms not
designated as main or primary load-carrying members, and unspliced rolled beam bridges.
Fabricators qualified under this category are also qualified to perform work as described
under the Conventional Steel Building Structures Category.

•

Major Steel Bridges

- Required for all steel bridges (including welded or bolted truss

structures),  welded  truss  and  pole  type  highway  sign,  lighting  and  traffic  structures,  and
bridge  elements  not  defined  as  miscellaneous  components  or  covered  by  Simple  Steel
Bridge  Structures  in  the previous  bullet.  Fabricators qualified  under this category  are  also
qualified to perform work as described under the Simple Steel Bridge and Conventional Steel
Building Structures Categories.

•

Fracture Critical Endorsement

- Required for any fabrication conducted on fracture critical

structures or components.

The Contractor shall ensure that structural steel members that contribute to a

design’s structural

capacity,  if  they  are  to  be  welded,  have  a  maximum  carbon  equivalent  (CE)  of  0.48.  Steels  that
conform to ASTM A709 / A709M - 11 HPS 50 or 70 (HPS 345 or 485) with carbon contents 0.10 %
or less are exempted from this rule. The Engineer may allow steels with up to CE 0.58 only if the
Contractor  uses  an  adjusted  welding  procedure  that  has  been  approved  by  the  Engineer.  The
Contractor  shall  submit  steel  mill  certifications  that  indicate  that  the  steel  meets  the  Contract

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Equation 23-1 to calculate the carbon equivalent.

𝐂𝐄 = 𝐂 +

(𝐌𝐧 + 𝐒𝐢)

𝟔

(𝐂𝐫 + 𝐌𝐨 + 𝐕)

𝟓

(𝐍𝐢 + 𝐂𝐮)

𝟏𝟓

Equation 23-1: Carbon equivalent

23.4.1.1

Structural Carbon Steel

Unless otherwise specified in the Contract documents, structural carbon steel for bolted or welded
construction shall be grade 250 steel that conforms to

Standard Specification for Structural Steel for

Bridges

(AASHTO M 270M/M 270-12) or (ASTM A709 / A709M - 11).

23.4.1.2

High-strength, Low-alloy Structural Steel

High-strength, low-alloy steel shall be grade 345, 345S, 345W, or HPS 345W, as defined in

Standard

Specification for Structural Steel for Bridges

(AASHTO M 270M/M 270-12) or (ASTM A709 / A709M

- 11).

23.4.1.3

High-strength, Low-alloy, Quenched, and Tempered Structural

Steel Plate

High-strength, low-alloy, quenched, and tempered steel plate shall be grade 485W or HPS 485W
steel that conforms to

Standard Specification for Structural Steel for Bridges

(AASHTO M 270M/M

270-12) or (ASTM A709 / A709M - 11).

23.4.1.4

High-yield-strength, Quenched, and Tempered Alloy-steel

Plate

High-yield-strength, quenched, and tempered alloy steel plate shall have the following properties:

a. Shall be grade 690 or 690W steel as defined in

Standard Specification for Structural Steel

for Bridges

(AASHTO M 270M/M 270-12) or (ASTM A709 / A709M - 11).

b. Shall be quenched-and-tempered alloy-steel structural shapes and seamless mechanical

tubing that meet all of the mechanical and chemical requirements for grade 690 and 690W

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steel, as defined in

Standard Specification for Structural Steel for Bridges

(AASHTO M

270M/M 270-12) or (ASTM A709 / A709M - 11), except that the specified maximum tensile
strength may be 965 MPa for structural shapes and 1000 MPa for seamless mechanical
tubing.

23.4.1.5

Eye Bars for Steel Structures

Steel for eye bars shall be of a grade that enables welding. Applicable structural steel shall conform
to one of the following grades:

a. Grade 250, as defined in

Standard Specification for Structural Steel for Bridges

(AASHTO M

270M/M 270-12) (ASTM A709 / A709M - 11)

b. Grade 345, 345W, or HPS 345W, as defines in

Standard Specification for Structural Steel for

Bridges

(AASHTO M 270M/M 270-12) or (ASTM A709 / A709M - 11)

23.4.1.6

Structural Tubing for Steel Structures

Structural tubing shall be either cold-formed welded or seamless tubing conforming to ASTM A500
/ A500M - 10a, Grade B, or hot-formed welded or seamless tubing conforming to ASTM A501 - 07.

23.4.1.7

Stainless Steel

All stainless steel shall be new and shall comply with the following specifications and requirements:

1. All members or parts called for on the Contract plans to be stainless steel shall be AISI Type

316 with a mill finish and complying with ASTM A276

– 13, unless otherwise indicated in the

Contract plans or specified in the particular specifications.

2. If specified, AISI Types 302, 303, 304 shall comply with ASTM A276

– 13.

3. Unless otherwise indicated on the Contract plans or in the Contract particular specifications,

all bolts shall be of the same type of stainless steel as the adjoining parts.

23.4.2

High-strength Fasteners for Steel Structures

High-strength bolts for structural steel joints shall conform to either AASHTO M 164-05 (ASTM A325
- 10) or AASHTO M 253-05 (ASTM A490 - 12). When high-strength bolts are used with unpainted
weathering grades steel, the bolts shall be type 3.

The Contractor shall use (ASTM A325

– 10) bolts in all bolted structural steel connections, unless

the connected assemblies or parts are designated as miscellaneous components and the fastener
assembly is specified elsewhere in the Contract documents.

The Contractor shall use (ASTM A490

– 12) bolts only with approval from the Engineer. The

Contractor shall provide procedures in accordance with for the handling, lubrication, installation,
tightening, and testing of (ASTM A490

– 12) bolts. The Contractor shall not install (ASTM A490 –

12) bolts without the Engineer

’s approval of the procedures.

A supplier

’s lot number shall appear on the shipping package. A certification shall note when and

where all testing, including rotational capacity tests, were done. For galvanized bolts and nuts, a
certification shall note zinc thicknesses.

Bolts shall not be harder than 33 HRC, as defined in AASHTO M 164-05 or ASTM A325 - 10.

Proof-load tests (ASTM F606 - 11a, Method I) shall be required for bolts. Wedge tests of full-size
bolts are required in accordance with Section 8.3 of AASHTO M 164-05 (ASTM A325 - 10).
Galvanized bolts shall be wedge tested after galvanising. Proof-load tests of AASHTO M 291-09
(ASTM A563 - 07a) are required for nuts. Proof-load tests for nuts to be used with galvanized bolts
shall be performed after galvanising, over tapping, and lubricating, except as noted below:

a. Nuts for AASHTO M 164-05 (ASTM A325 - 10) bolts shall conform to AASHTO M 291-09

(ASTM A563 - 07a), Grades DH, DH3, C, C3, and D (Property Class 8S, 8S3, l0S, or 10S3).

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b. Nuts for AASHTO M 253-05 (ASTM A490

– 12) bolts shall conform to the requirements of

AASHTO M 291-09 (ASTM A563 - 07a), Grades DH and DH3 (Property Class 10S or 10S3).

The exceptions are:

•

Nuts to be galvanized (hot-dip or mechanically galvanized) shall be Grade DH (Property

Class 10S).

•

Nuts to be used with AASHTO M 164-05 (ASTM A325 - 10) Type 3 bolts shall be Grade C3

or DH3 (Property Class 8S3 or 10S3). Nuts to be used with AASHTO M 253-05 (ASTM A490
– 12), Type 3 bolts shall be Grade DH3 (Property Class 10S3).

All galvanized nuts shall be lubricated with a lubricant containing a visible dye. Black bolts must be
oily to touch when delivered and installed.

Washers shall be hardened steel washers that conform to the requirements outlined in AASHTO M
293-10 or ASTM F436 - 11, and Article 23.6.9.6.

23.4.2.1

Identifying Marks for High-strength Fasteners

AASHTO M 164-05 (ASTM A325 - 10) for bolts and the specifications referenced herein for nuts
require that bolts and nuts manufactured to the specification be identified by specific markings atop
the bolt head and on one face of the nut. Head markings must identify the grade by the symbol
(A325), the Manufacturer, and, for type 3 bolts, the type. Nut markings must identify the property
class, the Manufacturer, and, for type 3 nuts, the type. Markings on direct tension indicators (DTI,
ASTM F959 - 09) must identify the Manufacturer and type (such as "325, Class 8.8"). Other washer
markings must identify the Manufacturer, and, for type 3 washers, the type.

To comply with AASHTO M 253-05 or ASTM A490

– 12, bolts must be identified by specific markings

on the top of the bolt head. Head markings

must identify the grade by the symbol (such as “A490"),

the Manufacturer, and, for type 3 bolts, the type.

To comply with AASHTO M 253-05 or ASTM A490

– 12 and the specifications referenced therein

for nuts, nuts must be identified on one face. Nut markings must identify the property class, the
Manufacturer and, for type 3 nuts, the type.

To comply with AASHTO M 253-05 or ASTM A490

– 12, direct tension indicators must have markings

that clearly identify the Manufacturer and Type "490" (Class" 10.9"). Markings on washers must
identify the Manufacturer, and, for type 3 washers, the type.

23.4.2.2

Dimensions of High-strength Fasteners

Bolt and nut dimensions shall conform to the requirements for heavy hexagon structural bolts and
heavy semi-finished hexagon nuts (metric heavy hexagon structural bolts and metric heavy semi-
finished hexagon nuts) given in ANSI/ASME B18.2.1-2010 Standards and B 18.2.2 (ASME/ANSI B
18.2.3.7M-2006 and ASME/ANSI B 18.2.4.6M-2010), respectively.

23.4.2.3

Galvanized High-strength Fasteners

AASHTO M 253-05 (ASTM A490

– 12) bolts shall not be galvanized.

When fasteners are galvanized, they shall be specified to be hot-dip galvanized in accordance with
AASHTO  M  232M/M  232-10  (ASTM  A153  /  A153M  -  09),  Class  C  or  mechanically  galvanized  in
accordance with  AASHTO  M 298-10 (ASTM B695  - 04(2009)), Class 50 (Class 345). Bolts to be
galvanized shall be either AASHTO M 164-05 (ASTM A325 - 10) Type I. Galvanized bolts shall be
tension tested after galvanising. Washers, nuts, and bolts of any assembly shall be galvanized by
the  same  process.  Nuts  should  be  over  tapped to the minimum  amount required for  the fastener
assembly and shall be lubricated with a lubricant containing a visible dye so a visual check can be
made for the lubricant at the time of field installation.

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23.4.2.4

Alternative Fasteners

The Contractor may use other fasteners or fastener assemblies, including the following:

a. Fasteners that conform to the requirements

outlined in ASTM’s Standard Specification for

“Twist Off” Type Tension Control Structural Bolt/Nut/Washer Assemblies, Steel, Heat
Treated, 120/105 ksi Minimum Tensile Strength (ASTM F1852 - 11).

b. Fasteners that meet the material, manufacturing, and chemical composition requirements

outlined in the AASHTO’s

Standard Specification for High-Strength Bolts for Structural Steel

Joints

(AASHTO M 164-05

), ASTM’s

Standard Specification for Structural Bolts, Steel, Heat

Treated, 120/105 ksi Minimum Tensile Strength

(ASTM A325 - 10), or the

Standard

Specification for Structural Bolts, Alloy Steel, Heat-Treated, 150 ksi Minimum Tensile
Strength

(AASHTO M 253-05) or (ASTM A490

– 12).

c. Fasteners that meet the mechanical property requirements of the same specifications that

apply for full size tests.

d. Fasteners with diametres and bearing areas under the head and nut that are at least

equivalent to those provided by a bolt and nut of the same nominal dimensions outlined in
Article 23.4.2.2.

These fasteners are subject to the approval of the Engineer. Such alternate fasteners may differ in
other dimensions from those of the specified bolts and nuts.

Subject  to the  approval  of  the  Engineer,  the  Contractor  may  use  high-strength steel  lock-pin  and
collar  fasteners  as  an  alternative  to  high-strength  bolts.  Shanks  and  heads  of  high-strength  steel
lock-pin  and  collar  fasteners  shall  meet  the  requirements  of  Article  23.4.2.2.  Each  fastener  shall
provide a solid-shank body of sufficient diametre to provide tensile and shear strength equivalent to
or  greater  than  that  of  the  bolt  specified  in  the  Contract  documents  and  shall  have  the  following
characteristics:

•

Have a cold-forged head on one end

•

Be of a type approved by the Engineer

•

Have dimensions as approved by the Engineer

•

Have a shank length that is suitable for the thickness of fastened material

•

Have locking grooves

•

Have a breakneck groove

•

Have pull grooves (annular grooves) on the opposite end

Each fastener shall provide a steel locking collar of a size that is appropriate for the diameter of the
fastener’s shank. By means of suitable installation tools, a fastener’s steel locking collar shall be
cold-swaged into the locking grooves, forming a head for the grooved end of the fastener after the
pull groove section has been removed. Such steel locking collars shall be a standard product of an
established Manufacturer of lock-pin and collar fasteners, as approved by the Engineer.

23.4.2.5

Load-indicator Devices

Load-indicating devices may be used in conjunction with bolts, nuts, and washers for high-strength
fasteners, as outlined in Section 23.4.2. Load-indicating devices shall conform to the requirements
of ASTM

’s

Specification for Compressible-Washer Type Direct Tension Indicators for Use with

Structural Fasteners

(ASTM F959 - 09), except as provided in the following paragraph.

Subject to the approval of the Engineer, the Contractor may use alternative design direct tension
indicating devices if they satisfy the requirements detailed in of Article 23.6.9.6 or other requirements
detailed in specifications provided by the Manufacturer and have the approval of the Engineer.

23.4.3

Other Structural Fasteners

23.4.3.1

Ordinary Bolt Assemblies

Shop and site bolts and nuts shall be to one the following grades:

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1. Grade 4.6 in accordance with BS 4190:2001
2. Grade 8.8 or 10.9 in accordance with BS 3692:2001.

Dimensions, tolerance and threaded length shall be to BS 4190:2001.

23.4.3.2

High Strength Friction Grip (HSFG) Bolt Assemblies

HSFG bolt assemblies shall be in accordance with BS EN 14399:2005.

23.4.3.3

Foundation Bolts

Holding down bolts shall be in accordance with BS 7419:2012.

23.4.3.4

Cup and Countersunk Bolts

Cup and countersunk bolts shall be in accordance with BS 4933:2010.

23.4.3.5

Washers

Unless otherwise specified metal washers for general engineering purpose shall be made in
accordance with BS 4320:1968, and black steel washers to Form E shall be used.

23.4.3.6

Lock Nuts

Lock nuts shall be in accordance with BS 4929-1:1973, BS EN ISO 7042:2012, and BS EN ISO
2320:2008.

23.4.4

Welded Stud Shear Connectors

Stud shear connectors shall be grade 1015, 1018, or 1020 cold-drawn bars that conform to the
requirements outlined in

ASTM’s

Standard Specification for Steel Bar, Carbon and Alloy,

Cold-Finished

(AASHTO M 169-09) or (ASTM A108 - 07). Such shear connectors shall be either

semi- or fully-killed. If flux retaining caps are used, steel for the caps shall be of a low-carbon grade
suitable for welding and shall comply with

ASTM’s

Standard Specification for Steel, Strip, Carbon

(0.25 Maximum Percent), Cold-Rolled

(ASTM A109 / A109M - 08).

Tensile properties, as determined by tests of bar stock after drawing or of finished studs, shall
conform to the requirements outlined in Table 23-3, in which the yield strength is as determined by
a two-tenth percent (0.2%) offset method.

Table 23-3: Tensile Properties of Stud Shear Connectors

Property

Required value

Tensile strength

420 MPa

Yield strength

345 MPa

Elongation

20% in 50 mm

Reduction areas

50%

23.4.4.1

Test Methods for Welded Stud Shear Connectors

Tensile properties shall be determined in accordance with the applicable sections of the Standard
Test Methods and Definitions for Mechanical Testing of Steel Products (AASHTO T 244-12) or
(ASTM A370 - 12). Tensile tests for finished studs shall be made on studs that are welded to test
plates using a test fixture similar to that shown in Figure 7.2 of the current AASHTO/AWS
D1.5M/D1.5:2010, Bridge Welding Code. If fracture occurs outside of the middle half of the gage
length, the test shall be repeated.

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23.4.4.2

Finish for Welded Stud Shear Connectors

Finished studs shall be of uniform quality and condition, free from irregularities such as laps, fins,
seams, cracks, twists, bends, or other injurious defects. Finish shall be as produced by cold-drawing,
cold-rolling, or machining.

23.4.4.3

Certification for Welded Stud Shear Connectors

The Manufacturer shall certify that the studs as delivered are in accordance with the material
requirements outlined in this chapter. Certified copies of in-plant quality-control test reports shall be
furnished to the Engineer upon request.

23.4.4.4

Check Samples for Welded Stud Shear Connectors

At the Contractor's expense, the Engineer may select studs of each type and size for checking as
necessary to validate that they meet the requirements outlined in this chapter.

23.4.5

Steel Forgings for Steel Structures

Steel forgings shall conform to the

Standard Specification for Steel Forgings, Carbon and Alloy, for

General Industrial Use

, AASHTO M 102M/M 102-06 (R2011) (ASTM A668 / A668M - 04(2009)),

Classes C, D, F, or G.

23.4.6

Cold-finished Carbon Steel Shafting for Steel Structures

Cold-finished carbon steel shafting shall conform to the

Standard Specification for Steel Bar, Carbon

and Alloy, Cold-Finished

, AASHTO M 169-09 (ASTM A108 - 07). Such steel shall be grades 10160

through 10300, inclusive, unless the Contract document specify otherwise.

23.4.7

Mild Steel Castings for Steel Structures

Steel castings for use in highway bridge components shall conform to

Standard Specification for

Castings, Steel and Alloy, Common Requirements, for General Industrial Use

, ASTM A781 / A781M

- 12a, Class 70 (Class 485), or

Standard Specifications for Steel Castings, Carbon, for General

Application

, AASHTO M 103M/M 103-12 (ASTM A27 / A27M - 10), Class 70 or Class 485 or Grade

485-250, unless otherwise specified in the Contract documents.

23.4.8

Chromium Alloy-steel Castings for Steel Structures

Chromium alloy-steel castings shall conform to the

Standard Specification for Castings, Iron-

Chromium, Iron-Chromium-Nickel, Corrosion Resistant, for General Application

, AASHTO M

163M/M 163-07 (2012) (ASTM A743 / A743M - 06(2010)). Such steel casting shall be grade CA
15M, unless the Contract documents specify otherwise.

23.4.9

Iron Castings for Steel Structures

Gray iron castings shall conform to the

Standard Specification for Gray Iron Castings

, AASHTO M

105-09 or ASTM A48 / A48M - 03(2008), Class 30, unless otherwise specified in the Contract
documents.

Ductile iron castings shall conform to the

Standard

Specification for Ductile Iron Castings

, ASTM

A536 - 84(2009), Grade 420-280-18, unless otherwise specified in the Contract documents.

Test specimens from parts integral with the castings, such as risers, shall be tested for castings with
a weight more than 4.45 kN to determine that the required quality is obtained in the castings in the
finished condition.

Malleable castings shall conform to the

Standard Specification for Ferritic Malleable Iron Castings

ASTM A47 / A47M - 99(2009). Grade 35018 (Grade 24118) shall be furnished unless otherwise
specified in the Contract documents.

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23.4.9.1

Work Quality and Finish for Iron Castings

Iron castings shall be true to pattern in form and dimensions, free from pouring faults, sponginess,
cracks, blow holes, and other defects in positions that affect their strength and function for the service
intended.

Castings shall be boldly filleted at angles and the arises shall be sharp and perfect.

23.4.9.2

Cleaning Iron Castings

All castings must be sandblasted or otherwise effectively cleaned of scale and sand to present a
smooth, clean, and uniform surface.

23.4.10

Galvanising Steel Structures

When galvanising is specified in the Contract documents, ferrous metal products, other than
fasteners and hardware items, shall be galvanized in accordance with the Standard Specification for
Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products, AASHTO M 111M/M 111-11 (ASTM
A123 / A123M - 12). Fasteners and hardware items shall be galvanized in accordance with the
Standard Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware, AASHTO M 232M/M
232-10 (ASTM A153 / A153M - 09), except as noted in Article 23.4.2.3.

23.4.11

Welding Steel Structures

All welding shall comply with all requirements as specified herein and as indicated on the Contract
plans.

23.4.11.1 Materials

a. Before any electrodes or flux-electrode combinations are used for welding steel, the

Contractor shall furnish certified copies of test reports for all the pertinent tests specified in
AWS A5.1/A5.1M-2004, AWS A5.5/A5.5M:2006, ANSI/AWS A5.17/ A5.17M-97 (R2007),
ANSI/AWS

A5.18/A5.18M:2005,

AWS

A5.23/A5.23M:

2011,

ANSI/AWS

A5.28/A5.28M:2005,  whichever  is  applicable,  made  on  electrodes  or  flux-electrode
combinations of the same class, size and brand as the electrodes to be used. If electrodes
are  to  be  used  which  are  of  a  size  for  which  tests  are  not  required  by  the  specifications
governing the process applicable to those electrodes, the test reports shall be furnished for
electrodes of the size nearest and of the same classification and brand as those to be used.
The tests may have been made for process qualification or quality control, and shall have
been made within one year prior to the manufacture of the electrodes and fluxes to be used.
The  report  shall  include  the  manufacturer's  certification  that  the  process  and  material
requirements were the same for manufacturing the tested electrodes and the electrodes to
be used. All pertinent information concerning the tests required by the applicable electrode
specifications  shall  be  reported.  The  forms  and  certificates  shall  be  as  directed  by  the
Engineer.

b. Electrodes for manual shielded metal arc welding of structural steel, ASTM A36 / A36M - 08

or ASTM A588 / A588M - 10, shall comply with the requirements of AWS A5.1/A5.1M-2004
or AWS A5.5/A5.5M:2006 for E7016, E7018, E7048, or E7028 electrodes.

c. Electrodes and fluxes for automatic and semi-automatic submerged arc welding of structural

steel, ASTM A36 / A36M - 08 shall comply with the requirements of AWS ANSI/AWS A5.17/
A5.17M-97 (R2007) or AWS A5.23/A5.23M: 2011 for F62, F64, F66, F72, F74, or F76 and
for ASTM A588 / A588M - 10 shall comply with the requirements of ANSI/AWS A5.17/
A5.17M-97 (R2007) or ANSI/AWS A5.24/ A5.24M:2005 for F72, F74 or F76.

d. Solid and composite electrodes for automatic and semi-automatic gas metal-arc welding of

structural steel, ASTM A36 / A36M - 08 shall comply with the requirements of ANSI/AWS
A5.18/A5.18M:2005 or ANSI/AWS A5.28/A5.28M:2005 for ER 70S-2, 3, 6 or 7 electrodes.

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23.4.11.2 Construction Requirements

a. The work methods and procedures shall comply with the AWS specifications, or BS EN 1011-

2:2001 and tested in accordance with BS EN ISO 15614-1:2004+A2:2012 by the Contractor,
except as modified herein.

b. Procedures and tests shall be approved by an independent Inspection Authority. Welding

Procedure sheets shall be made available to the welder prior to the commencement of the
work and shall be available to the Engineer and Inspection Authority on request.

c. All welding shall be performed in such a manner that the Brinnell hardness of the weld metal

and heat-affected zone is within the limits computed from Equation 23-2 and Equation 23-3:

Minimum Brinnell Hardness =

Minimum specified tensile strength of parent metal

500

Equation 23-2: Minimum Brinnell hardness

Maximum Brinnell Hardness =

Max. specified or tested tensile strength of parent metal

500

+ 50

Equation 23-3: Maximum Brinnell hardness

d. The minimum preheat and interpass temperatures for welding structural steel shall comply

with Table 3.2,

Prequalified Minimum Preheat and Interpass Temperature,

ANSI/AWS

D1.1/D1.1M:2010, except that the minimum preheat for structural steel 1.8 cm or less in
thickness, shall not be less than 10

e. Automatic vertical shielded metal-arc welding processes, such as electroslag or electrogas,

may be used only on structural steel ASTM A36 / A36M - 08. The impact strength
requirements shall be included in the procedure qualification.

f. All welding shall be protected from air currents or drafts to prevent loss of heat or loss of arc

shielding. The method of protecting the welding area from loss of heat or loss of arc shielding
shall be subject to approval by the Engineer.

g. Areas contiguous to welding operations shall be preheated to a minimum temperature of 150

C when necessary, in the opinion of the Engineer, to prevent distortion or weld cracking.
Preheating to a temperature in excess of 200

C will not be required by the Engineer.

23.4.11.3 Qualification of Welders

a. Welder qualification tests will be evaluated in accordance with requirements of the current

AASHTO/AWS D1.5M/D1.5:2010,

Bridge Welding Code

. As an alternative, welders may be

tested to meet the requirements of BS EN 287-1:2011 but, in the case of welders engaged
on fillet welding only, BS 4872-1:1982 is an acceptable alternative.

b. Welder testing shall be witnessed and certificates endorsed by an independent Inspection

Authority.

c. The certification shall remain valid providing it complies with the conditions for re-approval of

certification specified in BS EN 287-1:2011.

d. In lieu of the AWS requirements, qualification tests for tack welding will be the same as the

qualification tests required for butt welding material up to and including 1.8 cm thick.

23.5

Fabricating Steel Structures

This section outlines standards and specifications for fabricating steel structures.

23.5.1

Cutting, Shearing, and Machining for Steel Plates

Cutting (including burning and sawing), shearing, and machining shall be accomplished in
accordance with the AASHTO/AWS D1.5M/D1.5:2010,

Bridge Welding Code

. In addition, the

Fabricator shall do the following:

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a. Plane, mill, grind, or thermally cut the sheared edges of main load-carrying member plate

components that are greater than 16 mm thick to a depth of 6 mm.

b. Cut and fabricate steel plates so that the primary direction of rolling is parallel to the direction

of the member

’s or component’s main stress. For flanges and webs, the direction of rolling

shall be parallel to the flanges, unless the Contract documents note otherwise. With approval
from the Engineer, the Fabricator may roll web splice plates parallel to their length.

Oxygen cutting of structural steel shall conform to the requirements of the current AASHTO/AWS
D1.5M/D1.5:2010,

Bridge Welding Code

Visual inspection and repair of plate-cut edges shall be in accordance with the current
AASHTO/AWS D1.5M/D1.5:2010,

Bridge Welding Code

23.5.2

Cold Bending Steel Plates

The Contractor shall submit cold bending procedures to the Engineer for review. Cold bending shall
comply with the specifications in the AASHTO/AWS D1.5M/D1.5:2010,

Bridge Welding Code

and

the provisions in this section. The Contractor shall not cold bend materials that are fracture-critical.
They shall not cold bend members or components that carry main loads. The Contractor shall visually
inspect all load points. Large dents or upsets will be cause for rejection. The Contractor shall use
magnetic particle examination or ultrasonic examination to discover any potentially damaged areas,
and then shall further inspect such areas.

23.5.2.1

Minimum Bend Radii and Other Requirements

The Contractor shall remove all sharp edges (including edges of holes if affected by the cold bending)
by grinding to a 1.6 mm radius. The Contractor shall submit material preparation procedures to the
Engineer for review.

Unless  otherwise  approved,  the  minimum  bend  radii  for  cold  bending  (at  room  temperature),
measured  to  the  concave face  of the  plate  shall be  as given  in  Table 23-4. If  a  smaller  radius  is
required, the Contractor may need to apply heat as part of the bending procedure in accordance with
Article 23.5.4.5. The Contractor shall submit the heating procedure to the Engineer for review.

For materials and grades not shown in Table 23-4, follow the minimum bend radii recommendations
of a plate

’s producer.

Table 23-4: Minimum Cold-bending Radii

Steel

grades

AASHTO M 270M/M 270-12

(ASTM A709 / A709M - 11), MPa

Thickness (t) mm

Up to 19 mm

Over 19 mm
to 25 mm

Over 25 mm
to 50 mm

Over

250

1.50 t

2.00 t

345, 345S, 345W, or HPS 345W

1.50 t

2.00 t

2.50 t

HPS 485W

1.50 t

2.50 t

3.00 t

690, 690W, or HPS 690W

1.75 t

2.25 t

4.50 t

5.50 t

As possible, bend lines shall be perpendicular to the direction of final rolling of the plate. If a bend
line is parallel to the direction of final rolling, multiply the suggested minimum radii in Table 23-4 by
1.5.

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23.5.3

Straightening Steel

When  permitted  by  the  Engineer,  plates,  angles,  other  shapes,  and  built-up  members  shall  be
straightened before the parts are assembled. The Fabricator shall perform straightening such that
no fracture, cracking or other damage occurs. If heat is to be used for straightening, such heating
shall comply with the specifications and requirements in Section 23.5.4. Distorted members shall be
straightened by mechanical means or, if approved by the Engineer, by carefully planned procedures
and supervised application of a limited amount of localized heat, except that heat-straightening of
AASHTO M 270M/M 270-12 (ASTM A709 / A709M - 11) (Grades HPS 485W and HPS 690W) steel
members  shall  be  done  only  under  rigidly  controlled  procedures,  each  application  subject  to  the
approval of the Engineer. In no case shall the maximum temperature exceed values in Table 23-5.

In all other steels, the temperature of the heated area shall not exceed 649°C as controlled by
temperature indicating crayons, liquids, or bimetal thermometers. Heating in excess of the limits
shown shall be cause for rejection, unless the Engineer allows testing to verify material integrity.

Parts to be heat-straightened shall be substantially free of stress and from external forces, except
stresses resulting from mechanical means used in conjunction with the application of heat.

Evidence of fracture following straightening of a bend or buckle will be cause for rejection of the
damaged piece.

23.5.4

Applying Heat to Steel

At various points during the fabrication of structural steel, applications of heat may be necessary for
hot-bending, cambering, curving, or straightening. The Fabricator shall use the temperature limits
and guidelines given in this section, unless alternate procedures have been approved by the
Engineer. Routine straightening of material other than quenched and tempered material shall be
done in accordance with the temperature limits and guidelines as specified in this section; the Owner
does not require the Contractor to submit a procedure for such routine straightening.

Heat curving may be used in conjunction with a cut-curve procedure, in which a portion of the
curvature is obtained by cutting the plates to all or part of the required radius, except as limited by
Article 23.5.4.2.

23.5.4.1

Equipment and Process for Heating Steel

This section outlines requirements and specifications for the process and equipment used to heat
steel.

Maximum Temperatures

Table 23-5 indicates the maximum allowable temperature to which steel can be heated, as measured
by temperature-indicating crayons or other suitable means.

Table 23-5: Maximum temperature limits for heat applications

Steel grades

AASHTO M 270M/M 270-12 (ASTM A709 / A709M - 11), MPa

Maximum temperature

250

649

345, 345S, 345W, or

HPS 345W

649

HPS 485W

593

690 or 690W

593

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Timing Heat Applications

The Fabricator shall conduct heating operations before the application of coatings.

Allowable Preload Stresses

Preload compressive stresses will be permitted up to 0.5 times the minimum specified yield strength
(Fy) of the material. This stress limit is applicable to all steels covered by this specification as listed
in Table 23-5. If jacks are used, the Fabricator shall energize them and lock them off before applying
heat.

Heating Tips

The Fabricator shall apply heat using orifice tips only. Select tip sizes proportional to the thickness
of the heated material.

Torches

The Fabricator shall manipulate the heating torches to guard against general and surface
overheating. In addition, place heat reflective sheet material against the web before applying heat to
the inside flange surface. When heating the inside flange surface, point the torches to prevent
applying heat directly to the web.

Heating Patterns

Fundamental heating patterns (such as vee, line, edge, spot, and strip) may be used separately or
in combination. The Fabricator shall mark vee and strip heat patterns on the material surfaces before
heating. When heating, bring the steel within the planned pattern to the specified heating
temperature as rapidly as possible without overheating the steel. Apply heat in accordance with the
approved procedure.

Thin Wide Plates

The Fabricator shall prevent buckling of thin wide plates by not applying excessive heat.

Verification of Temperatures

The Fabricator shall use temperature sensitive crayons, pyrometres, or infrared non-contact
thermometres for verifying temperatures during heating operations. When heating patterns are used,
make regular verifications of the temperatures throughout the pattern. Remove the heating flame
from the material before taking measurements.

Cooling

Before using any artificial cooling, the Fabricator shall allow steel to cool naturally below 316° C. Use
only dry compressed air. Do not quench with water or a water and air mixture.

Reheating

The Fabricator shall reheat only after the material has cooled below 121° C.

Over Heating

The Engineer shall reject a product, if any portion of the material is exposed to heating higher than
the allowable temperature.

23.5.4.2

Heat-curving Bridge Members

This section outlines specifications for heat-curving bridge members, which is also known as

weak

axis shaping

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General Requirements for Heat-curving

Rolled beams and girders may be heat curved at the job site, provided that the heating is performed
in accordance with the Engineer

’s approval.

Flanges of curved, welded girders may be cut to the radii specified in the Contract documents or
curved by applying heat as specified in the succeeding articles providing the radii is not less than
allowed by Article 10.15.2, “Minimum Radius of Curvature,” of the AASHTO Standard Specifications
for Highway Bridges, Latest Edition, Design Specifications.

Materials for Rolled Beams and Welded Girders

Structural steels conforming to AASHTO M 270M/M 270-12 (ASTM A709 / A709M - 11), Grade 36,
50, 50S, 50W, HPS 50W, HPS 70W, or HPS 100W (Grade 250, 345, 345S, 345W, HPS 345W, HPS
485W, or HPS 690W) may be heat-curved.

Type of Heating for Rolled Beams and Welded Girders

Beams  and  girders  may  be  curved  by  either  continuous  or  V-type  heating  as  approved  by  the
Engineer.  For  the  continuous  method,  a  strip  or  intermittent  strips  along  the  edge  of  the  top  and
bottom  flange  shall  be  heated  approximately  simultaneously  depending  on  flange  widths  and
thicknesses; the strip shall be of sufficient width and temperature to obtain the required curvature.
For the V-type heating, the top and bottom flanges shall be heated in truncated triangular or wedge-
shaped areas having their base along the flange edge and spaced at regular intervals along each
flange; the spacing and temperature shall be as required to obtain the required curvature and heating
shall progress along the top and bottom flange at approximately the same rate.

For the V-type heating, the apex of the truncated triangular area applied to the inside flange surface
shall terminate just before the juncture of the web and the flange is reached. To avoid unnecessary
web distortion, special care shall be taken when heating the inside flange surfaces (the surfaces that
intersect the web) so that heat is not applied directly to the web. When the radius of curvature is 305
metres or more, the apex of the truncated triangular heating pattern applied to the outside flange
surface shall extend to the juncture of the flange and web. When the radius of curvature is less than
305 metres, the apex of the truncated triangular heating pattern applied to the outside flange surface
shall extend past the web for a distance equal to one-eighth of the flange width or 75mm, whichever
is less. The truncated triangular pattern shall have an included angle of approximately 15 to 30
degrees but the base of the triangle shall not exceed 250mm. Variations in the patterns prescribed
above may be made with the approval of the Engineer.

For both types of heating, the flange edges to be heated are those that will be on the inside of the
horizontal curve after cooling. Heating both inside and outside flange surfaces is only mandatory
when the flange thickness is 31mm or greater, in which case, the two surfaces shall be heated
concurrently. The maximum temperature shall be prescribed as per Article 23.5.4.1.

Sequence of Heat-curving Operations

The Fabricator shall heat curve girders before they are painted. The heat-curving operation may be
conducted either before or after all the required welding of transverse intermediate stiffeners is
completed. However, unless provisions are made for girder shrinkage, connection plates and bearing
stiffeners shall be located and attached after heat-curving. If longitudinal stiffeners are required, they
shall be heat-curved or oxygen-cut separately and then welded to the curved girder. When cover
plates are to be attached to rolled beams, they may be attached before heat-curving if the total
thickness of one flange and cover plate is less than 63.5mm and the radius of curvature is greater
than 305 metres. For other rolled beams with cover plates, the beams shall be heat-curved before
the cover plates are attached; cover plates shall be either heat-curved or oxygen-cut separately and
then welded to the curved beam.

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Web Position for Heat-curving

When the radius is less than 305 metres, the Fabricator shall heat curve members with the web in
the horizontal position or preloaded to induce stress before heating. Otherwise, members may be
heat curved with the web in either the vertical or horizontal position.

When heat-curving with the web in the horizontal position, provide intermediate safety catch blocks
between supports of the member and not more than 50 mm below the flanges to catch the member
in case of a sudden sag.

When heat-curving with the web in the vertical position, the member shall be braced or supported in
such a manner that the tendency of the member to deflect laterally during the heat-curving process
will not cause the member to overturn.

Subsequent Heat-curving Applications

If multiple locations are to be heated, the Fabricator shall not reheat the same location until after at
least three heats at other locations.

Locating Heating Patterns

The Fabricator shall space the heating patterns along the full length of each flange to produce a
circular (not parabolic) curvature. Adjust the heating patterns to produce the necessary curvature.
Compensate for differences in flange thickness and width as necessary. Use enough heating
patterns in each piece to eliminate chording effects.

Minimum Radius for Heat-curving

Heat-curving of beams and girders is allowed when the horizontal radius of curvature measured to
the centreline of the member web is greater than both values calculated in Equation 23-4 and
Equation 23-5, and greater than 45.7 metres at any and all cross sections throughout the length of
the member. Do not heat curve steels manufactured to a yield strength greater than 345 MPa, other
than ASTM A709 / A709M - 11, Grade HPS 485W.

R =

(7.3 bD)

√Fy Ψ t

Equation 23-4: Radius calculation 1

R =

(51720 b)

Fy Ψ

Equation 23-5: Radius calculation 2

Where:

Fy =

Specified minimum yield

point of member web, MPa

Ψ =

Ratio of the total cross

section area to the cross-sectional area of both flanges

b =

Width of the widest flange,

D =

Clear

distance

between

flanges, mm

t =

Web thickness, mm

R =

Radius, mm

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In addition to the above requirements, the Fabricator shall not heat curve if the radius is less than
305 metres when a flange

’s thickness exceeds 75 mm or its width exceeds 762 mm.

23.5.4.3

Heat-cambering Steel

This section outlines specifications for heat-cambering steel, which is also known as

strong axis

shaping

General Requirements For Heat-cambering

Girders shall be cambered before heat-curving. Camber for rolled beams may be obtained by heat-
cambering methods approved by the Engineer. For plate girders, the web shall be cut to the
prescribed camber with suitable allowance for shrinkage due to cutting, welding, and heat-curving.
However, subject to the approval of the Engineer, moderate deviations from specified camber may
be corrected by a carefully supervised application of heat.

Procedures for cambering of built-up plate girders shall be submitted as a part of the Quality Control
Plan. In the procedures, address any proposed preloading and heat application and control. Minor
heat adjustments in camber at the finishing stage of the girder do not require approval if the patterns
and temperatures are followed in accordance with the approved procedures. The Fabricator shall
not use heat-cambering as the primary source of vertical camber in horizontally curved main load-
carrying members; cut the web plate to the required position. Only use heat-cambering on
horizontally curved main members to adjust cut cambering with the approval of the Engineer.

Web Position for Heat-cambering

The Fabricator shall support members to be heat-cambered with the web vertical. Space supports
to take maximum advantage of dead load in the member before the application of heat.

Subsequent Heat-cambering Applications

If multiple locations are to be heated, the Fabricator shall not reheat the same location until after at
least three heats at other locations.

Heat-cambering Rolled Beams

Rolled beams may be heat-cambered to provide the required curvature at the producing mill. The
Fabricator shall attach all detail material, such as connection plates, bearing stiffeners and gusset
plates, after the beam has been heat-cambered.

Measurement of Curvature and Camber

Horizontal curvature and vertical camber shall be measured for final acceptance after all welding
and heating operations are completed and the flanges have cooled to a uniform temperature.
Horizontal curvature shall be checked with the girder in the vertical position.

23.5.4.4

Heat-straightening Damaged Structural Steel

The Fabricator shall submit procedures for heat-straightening for the Engineer to review before
beginning work. Such procedures shall describe, in detail, the distortion to be corrected and all
details for preloading, heating, cooling, verifying final dimensions, and non-destructive testing.

Heat-straightening Cracked Steel

As a minimum, the Fabricator shall visually inspect all heat-straightened areas. The Fabricator shall
notify the Engineer after finding any suspected areas of cracking. In accordance with direction from
the Engineer, the Fabricator shall inspect these areas by one or more of the following methods:

1.  Visual inspection
2.  Liquid penetrant examination as described in ASTM E165 / E165M - 12
3.  Magnetic particle examination as described in ASTM E709 - 08

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4. Ultrasonic examination as described in Section 6, Part C of the AASHTO/AWS

D1.5M/D1.5:2010,

Bridge Welding Code

5. Radiographic examination as described in Section 6, Part B of the AASHTO/AWS

D1.5M/D1.5:2010,

Bridge Welding Code

Restraining Forces for Heat-straightening Damaged Steel

Restraining forces (usually jacks) shall be set to restrain the steel during heating, but allow free
Contraction during cooling. In addition, the Fabricator shall apply the restraining forces in a direction
tending to restore the member and limit the magnitude so that the material is not overstressed during
heating.

Heating Damaged Structural Steel

The Fabricator shall heat the steel in a single pass following the specified pattern and allow it to cool
to below 121° C before reheating. The Fabricator shall select heating patterns and sequences that
are appropriate for the type of damage and shape of the cross section. Simultaneous vee heats may
be used if the clear spacing between vees is greater than the width of the plate element.

Subsequent Repairs after Heat-straightening Steel

The Fabricator may repair any members that are damaged after heat cambering. However, they
shall not repair previously heat-straightened members in the same region of damage without the
approval of the Engineer.

23.5.4.5

Hot Bending Steel Plates

Where a smaller radius than that allowed in  Section 23.5.2 is required, non-primary load carrying
components  may  be  bent  using  heating  together  with  mechanical  force  in  accordance  with  the
guidelines  provided  in  Article  23.5.4.1.  The  Fabricator  shall  apply  heat  uniformly  through  the
thickness of the plate. They shall provide the hot bending procedures to the Engineer for review.

23.5.4.6

Heat Treatment for Structural Steel

When any special form of heat treatment is required, it shall be described in the Contract documents.
The Fabricator shall perform heat treatments following any boring, machining and/or straightening
operations.

Normalizing and Annealing Structural Steel

Structural members that are indicated in the Contract documents to be annealed or normalized shall
have finished machining, boring, and straightening done subsequent to heat treatment. Normalizing
and annealing (full annealing) shall be as specified in ASTM A941 - 10a. Temperatures shall be
maintained uniformly throughout the furnace during the heating and cooling so that the temperature
at no two points on the member will differ by more than 55° C at any one time.

Members of AASHTO M 270M/M 270-12 (ASTM A709 / A709M - 11) Grades 690/690W or Grade
485W steels shall not be annealed or normalized and shall be stress relieved only with the approval
of the Engineer.

Relieving Stress during Heat Treatment for Structural Steel

Where required, the Fabricator shall perform thermal stress relief in accordance with the procedure
outlined in the AASHTO/AWS D1.5M/D1.5:2010,

Bridge Welding Code

. Welding materials shall be

consistent with the stress relieving process used.

A record of each furnace charge shall identify the pieces in the charge and show the temperatures
and  the  actually  used  schedule.  Proper  instruments,  including  recording  pyrometres,  shall  be
provided  for  determining  at  any  time  the  temperatures  of  members  in  the  furnace.  Records  of
treatment  operations  shall  be  available  to  and  meet  the  approval  of  the  Engineer.  Holding

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temperature for stress relieving shall be in accordance with Section 4.4 of the current AASHTO/A
WS D1.5M/D1.5

Bridge Welding Code

Members, such as bridge shoes, pedestals, or other parts that are built up by welding sections of
plate together shall be stress relieved in accordance with the procedure of Section 4.4 of the current
AASHTO/ A WS D 1.5M/D 1.5

Bridge Welding Code

, when required by the Contract documents.

23.5.5

Bolt Holes for Steel Structures

23.5.5.1

Holes for High-strength Bolts and Unfinished Bolts

All holes for bolts shall be either punched or drilled, except as noted herein. The width of each
standard hole shall be the nominal diameter of the bolt plus 1.6mm. The standard hole diameter for
metric bolts M24 and smaller shall be the nominal diameter of the bolt plus 2 mm. For metric bolts
M27 and larger, the standard hole diameter shall be the nominal diameter of the bolt plus 3 mm.

Except as noted in the sub-articles below, material forming parts of a member composed of not more
than five thicknesses of metal may be punched full-size.

When more than five thicknesses of material are joined or, as required by Article 23.5.5.5, material
shall be subdrilled or subpunched and then reamed full-size, or drilled full-size while in assembly.

When required, all holes shall be either subpunched or subdrilled 4.8mm smaller and, after
assembling, reamed or drilled to full size.

Holes in cross frames, lateral bracing components, and the corresponding holes in connection plates
between girders and cross frames or lateral components may be punched full size. Holes in
longitudinal main load-carrying members, transverse floor beams, and any components designated
as fracture critical (FCMs) shall not be punched full-size.

When shown in the Contract documents, enlarged or slotted holes are allowed with high-strength
bolts.

With the O

wner’s approval, round or slotted holes for non-main members in thin plate may be

thermally cut by plasma, laser, or oxygen-acetylene methods subject to the requirements herein.

Punched Holes

If any holes must be enlarged to admit the bolts, such holes shall be reamed. Holes must be clean-
cut without torn or ragged edges. The slightly conical hole that naturally results from punching
operations shall be considered acceptable.

Reamed or Drilled Holes

Reamed or drilled holes shall be cylindrical, perpendicular to the member, and shall comply with the
requirements of Article 23.5.5.1 as to size. Where practical, reamers shall be directed by mechanical
means. Burrs on the outside surfaces shall be removed. Reaming and drilling shall be done with
twist drills, twist reamers, or rotobroach cutters. Connecting parts requiring reamed or drilled holes
shall be assembled and securely held while being reamed or drilled and shall be match-marked
before disassembling.

Accuracy of Holes

Holes not more than 0.8mm larger in diameter than the true decimal equivalent of the nominal
diameter that may result from a drill or reamer of the nominal diameter shall be considered
acceptable. The width of slotted holes which are produced by thermal cutting or a combination of
drilling or punching and thermal cutting should be not more than 0.8mm greater than the nominal
width. The thermally-cut surface shall be ground smooth to obtain a maximum surface roughness of
ANSI

25 μm (RMS).

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23.5.5.2

Accuracy of Hole Group

Accuracy before Reaming

All holes punched full-size, subpunched, or subdrilled shall be so accurately punched that after
assembling (before any reaming is done) a cylindrical pin 3.2mm smaller in diameter than the
nominal size of the punched hole may be entered perpendicular to the face of the member, without
drifting, in at least 75 percent of the contiguous holes in the same plane. If the requirement is not
fulfilled, the badly punched pieces shall be rejected. If any hole will not pass a pin 4.8mm smaller in
diameter than the nominal size of the punched hole, this shall be cause for rejection.

Accuracy after Reaming

When holes are reamed or drilled, 85 percent of the holes in any contiguous group shall, after
reaming or drilling, show no offset greater than 0.8mm between adjacent thicknesses of metal.

All steel templates shall have hardened steel bushings in holes accurately dimensioned from the
centerlines of the connection as inscribed on the template. The centrelines shall be used in locating
accurately the template from the milled or scribed ends of the members.

23.5.5.3

Numerically-controlled Drilled Field Connections

In lieu of subsized holes and reaming while assembled, or drilling holes full-size while assembled,
the Contractor shall have the option to drill or punch bolt holes full-size in unassembled pieces and/or
connections including templates for use with matching subsized and reamed holes, by means of
suitable numerically-controlled (N/C) drilling or punching equipment. Full-size punched holes shall
meet the requirements of Article 23.5.5.1.

If N/C drilling or punching equipment is used, the Contractor shall be required to demonstrate the
accuracy of this drilling or punching procedure in accordance with the provisions of Article 23.6.1.4
by means of check assemblies.

Holes drilled or punched by N/C equipment shall be drilled or punched to appropriate size either
through individual pieces or drilled through any combination of pieces held tightly together.

23.5.5.4

Holes for Ribbed Bolts, Turned Bolts, or Other Approved

Bearing-type Bolts

All holes for ribbed bolts, turned bolts, or other approved bearing-type bolts shall be subpunched or
subdrilled 4.8mm smaller than the nominal diameter of the bolt and reamed when assembled, or
drilled to a steel template or, after assembling, drilled from the solid at the option of the Fabricator.
In any case, the finished holes shall provide a driving fit as specified in the Contract documents.

23.5.5.5

Preparation of Field Connections

Holes in all field connections and field splices of main member of trusses, arches, continuous-beam
spans, bents, towers (each face), plate girders, and rigid frames shall be subpunched or subdrilled
and  subsequently  reamed  while  assembled  or  drilled  full-size  through  a  steel  template  while
assembled.  Holes  in  cross  frames,  lateral  bracing  components,  and  the  corresponding  holes  in
connection plates between girders and cross frames or lateral components may be punched full size.
Holes  in  longitudinal  main  load-carrying  members,  transverse  floor  beams,  and  any  components
designated as fracture critical (FCMs) shall not be punched full-size. Holes for field splices of rolled
beam stringers continuous over floor beams or cross frames may be drilled full-size unassembled to
a steel template. All holes for floor beams or cross frames may be drilled full-size unassembled to a
steel  template,  except  that  all  holes  for  floor  beam  and  stringer  field  end  connections  shall  be
subpunched and reamed while assembled or drilled full-size to a steel template. Reaming or drilling
full-size of field-connection holes through a steel template shall be done after the template has been
located  with  utmost  care  as  to  position  and  angle  and  firmly  bolted  in  place.  Templates  used  for
reaming  matching  members  or  the  opposite  faces  of  a  single  member  shall  be  exact  duplicates.

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Templates used for connections on like parts or members shall be so accurately located that the
parts or members are duplicates and require no match-marking.

For any connection, in lieu of subpunching and reaming or subdrilling and reaming, the Fabricator
may, at

the Fabricator’s option, drill holes full-size with all thicknesses or material assembled in

proper position.

23.5.5.6

Slotted Bolt Holes

Slots may be made by a single punch, or by joining two adjacent drilled or punched holes when
punching is permitted. When joining holes, thermal cutting is to follow the common tangent to the
two holes, and this cut is to be ground. The Fabricator shall not make slotted holes more than 0.8
mm in width nor 1.6 mm greater in length than specified. The Fabricator shall grind smooth any flame
cut portions of the slot to ANSI 25 μm (RMS).

Unless shown otherwise in the Contract documents, the bolt (and anchor rod) slotted hole geometry
shall comply with the measurements shown in Table 23-6.

Table 23-6: Bolt hole geometry

Bolt
Diametre (d)

Standard
diametre

Oversize
diametre

Short-slotted (width
x length)

Long-slotted (width
x length)

12.7 mm

14.3 mm

15.9 mm

14.3 mm x 17.5 mm

14.3 mm x 31.7 mm

15.9 mm

17.5 mm

20.6 mm

17.5 mm x 22.2 mm

17.5 mm x 39.7 mm

19.0 mm

20.6 mm

23.8 mm

20.6 mm x 25.4 mm

20.6 mm x 47.6 mm

22.2 mm

23.8 mm

27.0 mm

23.8 mm x 28.6 mm

23.8 mm x 55.6 mm

25.4 mm

27.0 mm

31.7 mm

27.0 mm x 33.3 mm

27.0 mm x 63.5 mm

28.6+ mm

d + 1.6 mm

d + 7.9 mm

(d + 1.6 mm) X
(d + 9.5 mm)

(d + 1.6 mm) X (2.5 x
d)

Bolt Hole Tolerances and Quality

The Fabricator shall make bolt (and anchor rod) holes using any method suitable to him and as
specified in this section. With the Engineer

’s approval, the Fabricator may thermally cut holes for

high strength fasteners in main or primary load-carrying members that are not to be punched full
size. Such cutting shall comply with the specifications in this section. The Fabricator shall grind
thermally cut holes to make them smooth.

Holes in a bolt group relative to the same holes in the component or components it is joined to in a
connection shall not be misaligned more than 0.8mm for 85% of the bolt holes in that group. Bolt
holes are to be normal to the work and have no tears, cracks, fins, dirt, loose rust, burrs, or other
anomalies. Surfaces shall be flat within a slope of 1/20. Bolt holes shall be round within ± 0.8mm
and within ± 0.8mm of the specified size. For subsize holes, a pin 3.2 mm smaller than the subsize
holes must be able to pass through all assembled plies in at least 75% of the locations before
reaming. Holes inclined more than 3 degrees to a surface in any direction must have a hardened
beveled washer provided at that face. Unless the Contract documents specify otherwise, coating the
insides of bolt holes is not required.

23.5.5.7

Bolt Holes in Plates Not Subjected to Tensile Stress

The Fabricator may thermally cut large diametre holes in heavy plates, such as bearing plates, that
are not subjected to tensile stress and may thermally cut slotted holes in materials that are not
subject to tensile stress. The Fabricator shall follow such cutting with appropriate grinding to smooth

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the periphery. The Fabricator shall stop the practice if gouges or other defects occur or if the
Engineer so directs.

The Contractor shall not thermally cut holes in grade 690 or 690W steel, as defined in ASTM A709
/ A709M - 11. Provide hole centrelines aligned within ± 1.6mm of theoretical. The inside (cut) faces
of the hole are to be perpendicular to the plane of the plate. Eighty-five percent of the (open) hole
diametre is not to exceed that specified in the Contract documents, ± 1.6mm. Local notches, gouges
or the maximum diametre shall not exceed that specified in the Contract documents ± 2.4mm.

23.5.5.8

Bolts Configuration

Distances of Bolt Holes to the Edge of the Steel Structure

The Contractor shall ensure that the centre of each bolt hole is at least as far from the edge of the
steel structure as the measurement indicated in Table 23-7.

Table 23-7: Distances of bolt holes from edge of steel structure

Fastener size

Sheared edge

Rolled edges of plates or shapes or gas cut edges

15.9 mm

28.6 mm

22.2 mm

19.0 mm

31.7 mm

25.4 mm

22.2 mm

38.1 mm

31.7 mm

25.4 mm

44.4 mm

31.7 mm

Bolted Splice Gaps

Unless the Contract documents show otherwise, the tolerance for bolted splice gaps (open distance
face-of-web/flange to face-of-web/flange) shall be from zero (no gap between faces) to a maximum
of 3.2 mm greater than the gap shown on the Contract plans. If no gap is shown in the Contract
plans, assume that a nominal gap of 9.5 mm is required. In addition, meet the edge distance
requirements, provided above.

Maximum Distances between Edges to Hole Centres

Unless otherwise specified in the Contract documents, the maximum fabricated distance from any
edge to the centre of the hole shall be 8 times the thickness of the thinnest outside plate, not to
exceed 127 mm with no additional tolerance allowed.

Spaces between Bolt Holes

The Fabricator shall space bolt holes within ± 3.2mm of that shown in the Contract documents.

23.5.6

Contact and Bearing Surfaces for Steel Structures

Surface finishes of bearings, base plates, and other contact surfaces shall comply with the ANSI
surface roughness requirements as defined in ANSI/ASME B46.1-2009,

Surface Texture, Surface

Roughness, Waviness and Lay

, given in Table 23-8, ANSI Surface Roughness Requirements.

Table 23-8: ANSI surface roughness requirements

Surface

Roughness

Steel slabs

ANSI 50 μm (RMS)

Heavy plates in contact in shoes to be welded

ANSI 25 μm (RMS)

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Surface

Roughness

Milled ends of compression members, milled or ground ends of stiffeners
and fillers

ANSI

12.5

μm

(RMS)

Bridge rollers and rockers

ANSI 6.3 μm (RMS)

Pins and pin holes

ANSI 3.2 μm (RMS)

Sliding bearings

ANSI 3.2 μm (RMS)

23.5.7

Cleaning and Coating Steel Structures

The Contractor shall comply with the specifications outlined in Sections 24.3 and 24.4 of Chapter
24, Painting, when cleaning, coating, and galvanising steel structures.

In addition, the Contractor shall remove lubricants from the exposed surfaces of installed fastener
assemblies and other surfaces in accordance with the approved quality control plan or the paint
Manufacturer

’s recommendations before painting. The Contractor shall demonstrate the lubricant

removal procedures to the Engineer before preparing for painting. The Contractor shall bring to the
Engineer

’s attention any Manufacturer’s process or procedure that conflicts with those specified in

the Contract documents.

23.5.8

Geometry for Members of Steel Structures

This section outlines geometrical requirements for members of steel structures.

23.5.8.1

General Geometrical Requirements

This section outlines general geometrical requirements for members of steel structures.

Tolerances for Members of Steel Structures

The Contractor shall ensure that members of a steel structure comply with the following dimensional
tolerances:

•

Rolled shapes, plates, bars, wide flange sections and miscellaneous steel in accordance with

(ASTM A6 / A6M

– 12).

•

Fabricate girders in accordance with the AASHTO/AWS D1.5M/D1.5:2010,

Bridge Welding

Code

and as described later in this section.

•

For built-up members not specifically covered by AASHTO/AWS D1.5M/D1.5:2010, apply

AASHTO/AWS D1.5M/D1.5:2010,

Bridge Welding Code

, except as noted below or as

directed by the Engineer.

Camber and Sweep for Members of Steel Structures

Tolerances for camber and sweep of continuous and simply supported girders of any shape shall be
as described in the AASHTO/AWS D1.5M/D1.5:2010,

Bridge Welding Code

. Camber and sweep

tolerances for steel pier caps shall be the same as those specified for girders. Measure sweep for
horizontally curved members from the theoretical centreline for comparison to the aforementioned
requirements.

Alternate Sections for Members of Steel Structures

Rolled sections or fabricated sections of equal or slightly greater dimensions than the section
specified may be proposed for the Engineer

’s approval. Changes that reduce fatigue resistance or

significantly affect splice design or deflection will require complete design calculations.

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Web Flatness for Members of Steel Structures

Maximum deviation from flatness for webs of curved or cambered sections shall be the same as for
straight built up girders. Measure curved girder web flatness using a straightedge oriented
perpendicular

to the flanges (‘vertical’, flange to flange).

Girder Lengths for Steel Structures

If measuring girder length with a device that is free of thermal effects, appropriately adjust the
measurements to the reference temperature shown in the Contract documents. Measure the length
of horizontally curved girders along the arc.

23.5.8.2

Special Members of Steel Structures

This section outlines specifications for special members in steel structures.

Box Members as Bent Caps

Box members that function as bent caps must meet the requirements outlined in this section.

Tolerances:

Unless otherwise shown in the Contract documents, submit tolerances for bearing

planes and box twist to the Engineer for review and approval. Before submitting these tolerance
values for approval, coordinate between the erector and the Fabricator.

Bearings:

Unless otherwise specified in the Contract documents, each bearing is to be true to a

tolerance of 0.8 mm across its entire width in either direction.

Beam Trueness:

Unless otherwise specified in the Contract documents, the plane of beam supports

on the box girder (the bearing area specifically attached to the box girder) is to be true to the box
girder bearing within 1.6 mm in the short direction and true to the vertical axis of the nesting girders
(those girders attached to or resting on the box girder) within 1.6mm.

Trapezoidal Bridge Members

As a minimum, trapezoidal bridge members (tub or box girders) shall meet AASHTO/AWS
D1.5M/D1.5:2010,

Bridge Welding Code

dimensional tolerances. Camber may be verified with the

girder in its upright position, supported to avoid dead load deflections.

Pinholes

Unless shown elsewhere in the Contract documents, bore pinholes must meet the following
specifications:

•

True to the specified diametre

•

Smooth to ANSI 3 (3.2 μm)

•

At right angles with the axis of the member

•

Parallel with each other

•

With a diametre of the pinhole not exceeding that of the pin by more than 0.4 mm for pins

127 mm or less in diametre, or 0.8 mm for larger pins.

Truss Chord Joints

Abutting joints in truss chords not specified to be mill-to-bear, shall have openings of 6.3 mm ± 3.2
mm.

Abutting joints in truss chords specified to be mill-to-bear, shall be faced and brought into bearing.
When assembling truss chord joints, the Contractor shall provide 85% or more of the abutting
surfaces in full contact. Allowable visible gaps shall not exceed 0.4 mm.

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Horizontally Curved Beams and/or Skewed Steel Girders

Account for torsion induced deflections for horizontally curved beams and/or skewed steel girders.
Unless otherwise defined in the Contract documents, a horizontally curved beam or girder is a
longitudinal or transverse bridge component with a radius less than 3,048 metre anywhere along its
continuous length.

23.5.8.3

Dimensions and Tolerances as per BS & BS EN Standards

As an alternative, dimensions and tolerances may comply with the appropriate standard shown in
Table 23-9:

Table 23-9: Material and Dimension as per BS & BS EN Standards

Form

Material Quality

Dimensions

Dimension
Tolerances

U.B. and U.C.

BS 4-1:2005

BS EN 10034:1993

Joists

BS 4-1:2005

Channels

BS EN 10025-
2:2004

BS 4-1:2005

Angles

BS EN 10056-
1:1999

Plate and Flats

Not Applicable

BS EN
10029:20103

Structural Hollow Sections Hot
Finished

BS EN 10210-
1:2006

BS EN 10210-
2:2006

Hollow Sections Cold Formed

BS EN 10219-
2:2006

Galvanised Open Sections and
Strip

BS EN 10346:2009 Not Applicable

BS EN 10143:2006

Notes:

1. Material quality requirements for Fine Grain Steels and Weather resistant grades are given

in EN 10025-3:2004.

2. BS EN 10210-1 contains material quality requirements for Non-alloy and Fine Grain Steels.
3. Tolerances for plates cut from wide strip produced on continuous mills are given in BS EN

10051:2010.

23.5.9

Surface Condition

a. Steel surfaces when used shall not be more heavily pitted or rusted than Grade C of BS

7079:2009 Part A1.

b. Surface defects in hot rolled sections, plates and wide flats revealed during surface

preparation which are not in accordance with the requirements of BS EN 10163-1:2004 shall
be rectified accordingly.

c. Surface defects in hot rolled hollow sections revealed during surface preparation which are

not in accordance with the requirements of BS EN 10210-1:2006 shall be rectified
accordingly.

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23.5.10

Pins and rollers for Steel Structures

Pins and rollers shall be accurately turned to the dimensions shown on the Contract plans and shall
be straight, smooth, and free from flaws. Pins and rollers more than 225 mm in diameter shall be
forged and annealed. Pins and rollers 225 mm or less in diameter may be either forged and annealed
or cold- finished carbon-steel shafting.

In pins larger than 225 mm in diameter, a hole not less than 50 mm in diameter shall be bored full-
length along the axis after the forging has been allowed to cool to a temperature below the critical
range, under suitable conditions to prevent damage by rapid cooling, and before being annealed.

23.5.10.1 Boring Holes for Pins

Pin holes shall be bored true to the specified diameter, smooth and straight, at right angles with the
axis of the member and parallel with each other unless otherwise required. The final surface shall
be produced by a finishing cut.

Pin hole diameters shall not exceed that of the pin by more than 0.5 mm for pins 125 mm or less in
diameter, or by 0.8 mm for larger pins.

Distance outside to outside of end holes in tension members and inside to inside of end holes in
compression members shall not vary from that specified more than 0.8 mm. Boring of pin holes in
built-up members shall be done after the member has been assembled.

23.5.10.2 Threads for Bolts and Pins

Threads for all bolts and pins for structural steel construction shall conform to the

Specifications of

International Thread Standards

, UNC Thread ANSI B 1.1, Class 2A for external threads and Class

2B for internal threads, except that pin ends having a diameter of 35 mm or more shall be threaded
six threads to the inch (metric screw threads-M Profile ANSI B 1.13M with a tolerance Class 6g for
external threads and 6H for internal threads).

23.5.11

Eye Bars for Steel Structures

Pin holes may be flame-cut at least 50 mm smaller in diameter than the finished pin diameter. All
eye bars that are to be placed side by side in the structure shall be securely fastened together in the
order that they will be placed on and bored at both ends while so clamped. Eye bars shall be packed
and match-marked for shipment and erection. All identifying marks shall be stamped with steel
stencils on the edge of one head of each member after fabrication is completed so as to be visible
when the bars are nested in place on the structure. Steel die stamps shall be low stress-type. No
welding is allowed on eye bars or to secure adjacent eye bars.

The eye bars shall be straight and free from twists and the pin holes shall be accurately located on
the centreline of the bar. The inclination of any bar to the plane of the truss shall not exceed a slope
of five-tenth percent (0.5%). The edges of eye bars that lie between the transverse centreline of their
pin holes shall be cut simultaneously with two mechanically operated torches abreast of each other,
guided by a substantial template, in such a manner as to prevent distortion of the plates.

23.5.12

Stiffeners for Steel Structures

End bearing stiffeners for girders and stiffeners intended as supports for concentrated loads shall
have full bearing (either milled, ground, or on weldable steel in compression areas of flanges, welded
as specified in the Contract documents) on the flanges to which they transmit load or from which
they receive load. Intermediate stiffeners not intended to support concentrated loads, unless
specified in the Contract documents, shall have a tight fit against the compression flange.

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23.5.13

Abutting Joints for Steel Structures

Abutting ends in compression members of trusses and columns shall be milled or saw-cut to give a
square joint and uniform bearing. At other joints, not required to be faced, the opening shall not
exceed 10 mm.

23.5.14

Fabrication of Stainless Steel

Insofar as practicable, fabrication, fitting and assembly of stainless steel work shall be done in the
shop. Work that cannot be permanently shop-assembled shall be completely assembled, marked
and disassembled before shipment to ensure proper assembly in the field. Unless otherwise
specified, methods of fabrication, assembly and erection shall be at the discretion of the Contractor
and as approved by the Engineer. All exposed work shall be carefully matched to produce continuity
of line and design in accordance with the Contract plans. All joints in exposed work shall be
accurately fitted and firmly secured with hairline contacts.

All welding of stainless steel shall comply with AWS D 1.6/D1.6M: 2007,

Structural Welding Code -

Stainless Steel

. Type 308 weld rods shall be used in welding.

Type, size and spacing of welds shall be as shown on approved shop drawings. Welds behind
finished surfaces shall be done so as to minimize distortion and/or discoloration of the finished side.
All discoloration of finished surfaces due to welding shall be removed by mechanical or electrical
cleaning. All weld spatter and welding oxides on finished surface shall be removed by blasting,
grinding or an electrochemical process.

All stainless steel surfaces in contact with other dissimilar metals shall be provided with a 2 mm thick
neoprene gasket between contact faces.

23.5.15

Orthotropic-deck Superstructures

Dimensional tolerance limits for orthotropic-deck bridge members shall be applied to each completed
but unloaded member and shall be as specified in paragraph 3.5 of the current AASHTO/ A WS D
1.5M/D 1.5

Bridge Welding Code

, except as follows:

a. Deviations from detailed flatness, straightness, or curvature at any point shall be the

perpendicular distance from that point to a template edge which has the detailed straightness
or curvature and which is in contact with the element at two other points.

b. Template edge may have any length not exceeding the greatest dimension of the element

being examined and, for any panel, not exceeding 1.5 times the least dimension of the panel;
it may be placed anywhere within the boundaries of the element.

c. Deviations shall be measured between adjacent points of contact of the template edge with

the element; the distance between these adjacent points of contact shall be used in the
formulas to establish the tolerance limits for the segment being measured whenever this
distance is less than the applicable dimension of the element specified for the formula.

23.5.15.1 Flatness of Panels for Orthotropic-deck Superstructures

Maximum deviation

, δ, from detailed flatness or curvature of a panel shall not exceed the greater of

5 mm or the result of Equation 23-6.

δ ≤

726 √T

Equation 23-6: Maximum deviation from detailed flatness

Where:

δ =

Maximum deviation in mm.

D =

Least dimension along the

boundary of the panel in mm.

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T =

Minimum thickness of the

plate comprising the panel in mm.

23.5.15.2 Straightness of Longitudinal Stiffeners Subject to Calculated

Compressive Stress, Including Orthotropic-Deck Ribs

maximum deviation, δ, from detailed straightness or curvature in any direction perpendicular to its

length of a longitudinal web stiffener or other stiffener subject to calculated compressive stress shall
not exceed the result of Equation 23-7.

δ ≤

480

Equation 23-7: Maximum deviation from detailed straightness (longitudinal)

Where:

L = Length of the stiffener or rib between cross members, webs, or flanges, in mm.

23.5.15.3 Straightness of Transverse Web Stiffeners and Other

Stiffeners Not Subject to Calculated Compressive Stress

maximum deviation, δ, from detailed straightness or curvature in any direction perpendicular to its

length of a transverse web stiffener or other stiffener not subject to calculated compressive stress
shall not exceed the result of Equation 23-8.

δ ≤

240

Equation 23-8: Maximum deviation from detailed straightness (transverse)

Where:

L = Length of the stiffener or rib between cross members, webs, or flanges, in mm.

23.5.16

Full-size Tests for Steel Structures

When  full-size  tests  of  fabricated  structural  members  or  eye  bars  are  required  in  the  Contract
documents,  the  Contractor  shall  provide  suitable  facilities,  material,  supervision,  and  labour
necessary for making and recording the required tests. The Contractor shall provide the Engineer
with detailed testing plan that include the loading pattern and the testing setup, the number of cycles
per loading, the frequency of the loading, and the layout of the instrumentation gauges.

23.6

Assembly of Steel Structures

This section outlines standards and specifications for the assembly of steel structures.

23.6.1

Shop Assembly for Steel Structures

The Contractor shall ensure the fit of all connections and the geometry of all components. Unless
specified elsewhere in the Contract documents, the Contractor shall check the fit of all longitudinal
girder and beam lines in accordance the specifications outlined in this section. The Contractor shall
perform this before transporting pieces in question to the site for erection.

23.6.1.1

Progressive Girder or Truss Assembly

The Contractor shall assemble the structure for a minimum of three spans, panels, field sections,
segments or longitudinal chords of the structure. Successive assemblies shall consist of at least one
longitudinal segment of the previous assembly, repositioned as necessary for accurate alignment,
plus two or more longitudinal segments added at the advancing end. For entire structures less than
45.7 metres long or less than three segments, the entire longitudinal line shall be assembled. The

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Contractor shall meet the requirements outlined in Article 23.6.1.4 when using computer-numerically-
controlled drilling equipment.

When  a  transverse  structural  steel  member  or  members  is  required  for  the  continuation  of  the
uninterrupted girder or beam line, truss, arch rib, bent tower face or rigid frame, and is designated
elsewhere in the Contract documents to be shop assembled, the Fabricator may include this member
or  component  in  a  separate  subassembly  and  not  the  three  segment  longitudinal  assembly
(discussed above). If a member or component is combined in a different subassembly, the Fabricator
shall  include  the  longitudinal  member  or  component,  as  designated  elsewhere  in  the  Contract
documents  to  be shop  assembled,  directly  into  the  transverse  structural  member.  The  Fabricator
shall not include transverse members in a longitudinal assembly unless the Contract documents or
the  Engineer  direct  otherwise.  The  Fabricator  shall  account  for  end  rotations  and  deflections,  as
necessary, and submit the procedure to the Engineer for review.

23.6.1.2

Progressive Chord Assembly

When the Contract documents so specify, the Fabricator shall assemble truss chords for a minimum
of three panels or longitudinal segments of the structure. Successive assemblies shall consist of at
least one longitudinal segment of the previous assembly, repositioned as necessary for accurate
alignment, plus two or more longitudinal segments added at the advancing end. For entire structures
less than 45.7 metres long or less than three segments, the Fabricator shall assemble the entire
longitudinal line. The Fabricator shall meet the requirements outlined in Article 23.6.1.4 when using
computer-numerically-controlled drilling equipment.

The Fabricator shall account for transverse members that are indicted elsewhere in the Contract
documents to be included in the shop assembly, as outlined in Article 23.6.1.1.

When assembled in accordance with this subsection, the holes of connections shall be so located
that they shall be drilled to the final geometric angles. This shall require that the truss members,
when erected under the no load (or practically no load or stress) condition, must be bent and forced
to fit the end conditions. This condition introduces an initial reverse secondary stress that will
theoretically wane when the structure assumes the loading for which it is cambered. The Fabricator
shall submit the procedure to the Engineer for review.

23.6.1.3

Special Complete Structure Assembly

When the Contract documents specify otherwise, a special complete shop assembly shall include
assembling the entire structure, including the diaphragms, cross frames, integral steel substructure,
and floor components. Miscellaneous components are not included unless the Contract documents
direct otherwise. Procedures for each structure or structure type shall include incremental erection,
temporary field support locations, stage construction, and final tightening of field connections. The
Contractor shall submit the procedures to the Engineer for review.

23.6.1.4

Computer-numerically-controlled (CNC) Drilling Associated

with Progressive Girder, Truss or Chord Assembly

If the Fabricator chooses to drill the holes in all plies of all connections of the continuous main girder
or beam line, truss, arch rib, bent, tower face or rigid frame and any intersecting (transverse)
members using computer-controlled numerical drilling procedures, piece-wise assembly of the entire
continuous girder or beam line, truss, arch rib, bent, tower face or rigid frame is not required if the
requirements outlined in this section are met.

Before transporting to a site, the Fabricator shall perform a check fit of the first three spans, panels,
field sections, segments or longitudinal chords; or entire first bent, tower face or rigid frame of the
structure to ensure the accuracy of the CNC procedures and equipment.

As selected by and at the discretion of the Engineer and before transporting to the site, the Fabricator
shall perform another check fit of a different assembly of three spans, panels, field sections,
segments or longitudinal chords; or another entire bent, tower face or rigid frame of the structure to

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ensure that the accuracy of the CNC procedures and equipment is maintained. If either of the above
fails to meet the Contract requirements, the Fabricator shall assemble the entire girder or beam line,
truss, arch rib, bent, tower face or rigid frame as originally prescribed in Article 23.6.1.1 or Article
23.6.1.2 as prescribed elsewhere in the Contract documents. Account for transverse members
indicated elsewhere in the Contract documents to be included in the shop assembly as in Article
23.6.1.1.

23.6.2

Evaluation of Steel Structure Assemblies

The Engineer shall evaluate and accept materials and work conforming to the Contract documents.
These evaluations may take place before or following delivery of the materials to the site of the
structure. Materials or work that fails to meet the Contract requirements shall be rejected.

The Engineer may, at their discretion, permit further inspections and testing of materials or work that
fail to meet the Contract requirements for acceptance. The Contractor shall bear the cost of such
inspections and tests.

The Contractor shall bring to the attention of the Engineer all nonconforming work and or materials
that cannot be brought into conformance with the Contract documents using pre-established
procedures, as outlined in the quality control plan that has been approved by the Owner. The
Contractor shall submit the following information to the Engineer:

a. A cover letter prepared on the Contractor

’s letterhead and addressed to the Engineer briefly

describing the nonconforming work and the proposed credit to the Contract proportionate to
the nonconformance. For each fabricating facility and for each project within that fabrication
facility, submittals must be numbered consecutively beginning with the number 1, at the start
of each project. Erectors will start with one for each individual project.

b. A completed Owner Nonconforming Structural Steel and Miscellaneous Metal Component

Data Sheet, prepared by the Contractor and countersigned by the Engineer

’s designated

representative to indicate agreement between the Contractor and the Owner regarding the
nonconformance, not any solution, resolution, or credit. If the Contractor and the Engineer

’s

designated representative are not in agreement regarding the nonconformance, the
Engineer

’s designated representative will either reject the submittal, indicating their reasons

for the rejection, or modify the submittal and forward to the Engineer. In the event of
modification, the Contractor shall initial the submittal before it is forwarded to the Engineer,
thereby indicating the Contract

or’s concurrence with the modification.

c. A list of supporting information, such as sketches, documentation, calculations, and pictures,

must be included in the appropriate space on the Nonconforming Component Data Sheet.
Supporting information regarding the Contract noncompliance in the form of separate
documents is only necessary when space on the Owner Nonconforming Structural Steel and
Miscellaneous Metal Component Data Sheet is inadequate for the required data. All of the
supporting information required for the form must be prepared by or under the supervision of
the Professional Engineer who will sign and seal one complete copy of the supporting
information.

If the Engineer so requests, the Contractor shall submit a structural and durability evaluation of the
proposed repair or remediation. This evaluation must be conducted under the supervision of a
Professional Engineer and the submittal shall bear the Professional Engineer

’s signature and seal.

23.6.3

Certification of Members or Components of Steel Structures

The Contractor shall coordinate with the Engineer to schedule final inspection of the completed work
within two weeks before shipment or erection to verify that all the Contract document requirements
have been met. After verification that all the Contract document requirements have been met and all
necessary repairs have been satisfactorily completed, the Quality Control Manager shall certify, by
initials or signature, such materials, components or members. The record shall include certification
for the following items:

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a. Items being shipped or stored before final assembly. The Contractor shall affix a certification

in the form of a stamp or tag in accordance with 23.2.5 and as indicated in the Quality Control
Plan, and with a copy of the certification placed in the Contract

or’s permanent project records,

b. Work being placed into its final position. Such documentation shall comply with the approved

Quality Control Plan and shall reside in the Contract

or’s permanent project records.

The Contractor shall submit a summary certification at the least once a month or with each payment
request that includes the following or similar wording.

“The undersigned, being a responsible official of (insert the Contractor identification) certifies that
the materials, components or members listed herein have been produced under strict quality control
and meet the requirements of the Contract documents.

”

Include a positive identification in the certification such that the applicable materials, components or
members can be uniquely identified using just the summary certification document. A Quality Control
Manager shall sign this summary certification.

23.6.4

Bolting Steel Structures

Surfaces of metal in contact shall be cleaned before assembling. Parts of a member shall be
assembled, well pinned, and firmly drawn together before drilling, reaming, or bolting is commenced.
Assembled pieces shall be taken apart, if necessary, for the removal of burrs and shavings produced
by the operation. Members shall be free from twists, bends, and other deformations.

Drifting done during assembly shall be only such as to bring the parts into position and shall not be
sufficient to enlarge holes or distort metal.

23.6.5

Welded Connections for Steel Structures

Surfaces and edges to be welded shall be smooth, uniform, clean, and free of defects which would
adversely affect the quality of the weld. Edge preparation shall be done in accordance with the
current AASHTO/AWS D1.5M/D1.5:2010,

Bridge Welding Code

23.6.6

Preassembly of Field Connections for Steel Structures

Field  connections  of  main  members  of  trusses,  arches,  continuous  beams,  plate  girders,  bents,
towers, and rigid frames shall be preassembled before erection as necessary to verify the geometry
of the completed structure or unit and to verify or prepare field splices. Attaining accurate geometry
is the responsibility of the Contractor, who shall propose an appropriate method of preassembly for
approval by the Engineer. Methods and details of preassembly shall be consistent with the erection
procedure  shown  on  the  erection  plans  and  camber  diagrams  prepared  by  the  Contractor  and
approved  by  the  Engineer.  As  a  minimum,  a  preassembly  procedure  shall  consist  of  assembling
three  contiguous  panels  accurately  adjusted  for  line  and  camber.  Successive  assemblies  shall
consist  of  at  least  one  section  or  panel  of  the  previous  assembly  (repositioned  if  necessary  and
adequately pinned to assure accurate alignment) plus two or more sections or panels added at the
advancing end. In the case of structures longer than 46 m, each assembly shall be not less than
45.7 m long regardless of the length of individual continuous panels or sections. At the option of the
Fabricator, the sequence of assembly may start from any location in the structure and proceed in
one or both directions as long as the preceding requirements are satisfied.

At the discretion of the Engineer, if the pre-assembly procedure causes any damage to connections
or any of the structural attachments, the affected part shall be replaced at the Contractor's expense.

23.6.6.1

Bolted Connections for Steel Structures

For bolted connections, holes shall be prepared as outlined in Section 23.5.5. Where applicable,
major components shall be assembled with milled ends of compression members in full bearing and
then shall have their subsized holes reamed to the specified size while the connections are
assembled.

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Ordinary Bolted Assemblies

The combination of bolts and nuts for ordinary bolted assemblies shall comply with BS 4190:2001
and BS 3692:2001. Any bolt assemblies which seize when being tightened shall be replaced.
Different bolt grades of the same diameter shall not be used in the same structure unless otherwise
agreed by the Engineer.

The bolt length shall be chosen such that, after tightening, at least one thread plus the thread run-
out will be clear between the nut and the unthreaded shank of the bolt and at least one clear thread
shall show above the nut.

When the members being connected have a finished surface protective treatment which may be
damaged by the nut or bolt head being rotated, a washer shall be placed under the rotating part.

A suitable plate, or heavy duty, washer shall be used under the head and nut when bolts are used
to assemble components with oversize or slotted holes.

When the bolt head or nut is in contact with a surface which is inclined at more than 30

plane at right angles to the bolt axis, a taper washer shall be placed to achieve satisfactory bearing.

Nuts shall be checked after being galvanized for free running on the bolt and retapped if necessary
to ensure a satisfactory tightening performance.

Bolts may be assembled using power tools or shall be fully tightened by hand using appropriate
spanners in accordance with BS 2583:1955.

Precision bolts to BS 3692:2001 may be used as fitted bolts when holes are drilled or reamed after
assembly so that the clearance in the hole is not more than 0.3 mm.

Where parts cannot be brought together by drifting without distorting the steelwork, rectification may
be made by reaming with the approval of the Engineer, provided the design of the connection will
allow the use of larger diameter holes and bolts.

High Strength Friction Grip Assemblies

The combination of bolts, nuts, and washers for high strength friction grip bolts shall comply with BS
EN 14399:2005 parts 1 to 8 as appropriate.

The use of friction grip bolts shall comply with BS EN 1993-1-8:2005. Tightening which complies with
BS EN 1993-1-8:2005 may be by the torque control method, part-turn method, or with load indicating
devices used in accordance with the Manufacturer's recommendations.

When considering the coefficient of friction to use in the design of high strength friction grip bolted
connections, the following values shall be used:

1. Unless the Engineer advises otherwise, untreated surfaces which are in accordance with BS

EN 1993-1-8:2005 may be considered as having a slip factor of 0.45; masking shall be used
to keep the surfaces free of protective treatments.

2. Surfaces which have been machined, or given any type of treatment, shall have the slip factor

determined by tests carried out in accordance with BS EN 1993-1-8:2005.

If, after complete tightening, a bolt or nut has to be slackened off, the whole bolt assembly is to be
disposed of.

Where parts cannot be brought together by drifting without distorting the steelwork, rectification can
be made with the Engineer approval by reaming, provided that the design of the connection will allow
the use of larger diameter bolts. Calculations shall be made to demonstrate that the connection
remains adequate for the forces in the connection.

23.6.6.2

Checking Assembly for Numerically-controlled Drilling

When the Contractor elects to use numerically-controlled drilling, a check of assembly shall be
required for each major structural type of each project, unless otherwise designated in the Contract
documents, and shall consist of at least three contiguous shop sections or, in a truss, all members

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in at least three contiguous panels but not less than the number of panels associated with three
contiguous chord lengths (that is, length between field splices).

Check assemblies should be based on the proposed order of erection, joints in bearings, special
complex points, and similar considerations.

If the check assembly fails in some specific manner to demonstrate that the required accuracy is
being obtained, further check assemblies may be required by the Engineer for which there shall be
no additional cost to the Owner.

Each assembly, including camber, alignment, accuracy of holes, and fit of milled joints, shall be
approved by the Engineer before reaming is commenced or before an N/C drilled check assembly
is dismantled.

23.6.6.3

Field-welded Connections for Steel Structures

For field-welded connections the fit of members including the proper space between abutting flanges
shall be prepared or verified with the segment preassembled in accordance with Section 23.6.6.

23.6.7

Match-marking Connecting Parts for Steel Structures

Connecting parts preassembled in the shop to assure proper fit in the field shall be match-marked,
and a diagram showing such marks shall be furnished to the Engineer.

23.6.8

Steel Structure Connections Using Unfinished, Turned, or
Ribbed Bolts

When unfinished bolts are specified, the bolts shall be unfinished, turned, or ribbed bolts conforming
to the requirements for Grade A bolts of

Standard Specification for Carbon Steel Bolts and Studs,

60 000 PSI Tensile Strength

, ASTM A307 - 10, and

Standard Specification for Carbon and Alloy

Steel Externally Threaded Metric Fasteners

, ASTM F568M-07 (Property Class 4.6, 400-MPa tensile

strength). Bolts shall have single self-locking nuts or double nuts unless otherwise specified in the
Contract documents. Beveled washers shall be used where bearing faces have a slope of more than
1:20 with respect to a plane normal to the bolt axis. The specifications of this section do not pertain
to the use of high-strength bolts. Bolted connections fabricated with high-strength bolts shall conform
to Section 23.6.9.

23.6.8.1

Turned Bolts for Steel Structures

The surface of the body of turned bolts shall meet the ANSI/ASME B46.1-2009 roughness rating
value of 3.2 μm. Heads and nuts shall be hexagonal with standard dimensions for bolts of the nominal
size specified or the next larger nominal size. Diameter of threads shall be equal to the body of the
bolt or the nominal diameter of the bolt specified. Holes for turned bolts shall be carefully reamed
with bolts furnished to provide for a light driving fit. Threads shall be entirely outside of the holes. A
washer shall be provided under the nut. Shop assemblies other than the check assemblies will not
be required.

23.6.8.2

Ribbed Bolts for Steel Structures

The body of ribbed bolts shall be of an approved form with continuous longitudinal ribs. A diameter
of the body measured on a circle through the points of the ribs shall be 2 mm greater than the nominal
diameter specified for the bolts.

Ribbed bolts shall be furnished with round heads conforming to ASME/ANSI B 18.5-2008,

Round

head short square neck bolts,

(ANSI B 18.5.2.2 M or B 18.5.2.3 M) as specified. Nuts shall be

hexagonal, either recessed or with a washer of suitable thickness. Ribbed bolts shall make a driving
fit with the holes. The hardness of the ribs shall be such that the ribs do not distort to permit the bolts
to turn in the holes during tightening. If for any reason the bolt twists before drawing tight, the hole
shall be carefully reamed and an oversized bolt used as a replacement.

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