60 41 00 SteelStr.pdf

Lower Rio Grande Flood Control Project – Interior Floodways Rehabilitation of North Floodway (North and South Levees) and Arroyo Colorado Floodway (North Levee) Hidalgo and Cameron Counties, Texas

STEEL STRUCTURES

USIBWC Contract No.: IBM09B0004 Page 60.41.00 - 1

SPECIFICATION 60 41 00

This specification includes requirements for the fabrication of steel material and construction of steel structures within the work area, and includes the following:

1.0 General

2.0 Materials & Equipment

3.0 Construction Methods

4.0 Measurement and Payment

PART 1 - GENERAL

1.1 RELATED DOCUMENTS, CONTRACT CLAUSES, & SPECIFICATIONS

The following may not include all related documents, contract clauses, & technical specifications, and does not relieve the Contractor of the responsibility of performing work associated with this specification in accordance with all terms of the Contract herein.

A. Related documents: As described in paragraph 1.2 of SPECIFICATION 01 01 00.

B. Contract: Section I, 52.236-21“Specifications and Drawings for Construction”

C. Technical Specifications:

• SPECIFICATION 60 20 00, “Concrete Structures”

• SPECIFICATION 60 42 00, “Metal for Structures”

• SPECIFICATION 60 45 00, “Galvanizing”

• SPECIFICATION 60 46 00, “Cleaning and Painting Steel”

• SPECIFICATION 60 47 00, “Structural Bolting”

• SPECIFICATION 60 48 00, “Structural Field Welding”

D. References:

• American Association of State Highway and Transportation Officials (AASHTO)/ National Steel Bridge Association (NSBA) Steel Bridge Collaboration S2.1-2002, “Steel Bridge Fabrication Guide Specification”

• American Society of Testing and Materials (ASTM) A6 / A6M - 09 Standard Specification for General Requirements for Rolled Structural Steel Bars, Plates, Shapes, and Sheet Piling

• ASTM A90 / A90M - 09 Standard Test Method for Weight [Mass] of Coating on Iron and Steel Articles with Zinc or Zinc-Alloy Coatings

• ASTM A588 / A588M - 05 Standard Specification for High-Strength Low-Alloy Structural Steel, up to 50 ksi [345 MPa] Minimum Yield Point, with Atmospheric Corrosion Resistance

USIBWC Contract No.: IBM09B0004 Page 60.41.00 - 2

• ASTM A709 / A709M - 09 Standard Specification for Structural Steel for Bridges

• ASTM A941 - 09 Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys

• ASTM E1815 - 08 Standard Test Method for Classification of Film Systems for Industrial Radiography

• American Welding Society (AWS) A5 Filler Metal Specifications

• AASHTO/AWS D1.5M/D1.5:2008, Bridge Welding Code

• ANSI/AWS D1.3:2008, Structural Welding Code—Sheet Steel,

• AWS D1.1:2008, Structural Welding Code—Steel,

• Texas Department of Transportation Department Material Specification (DMS)-7360, “Qualification Procedure for Laboratories Performing Welding Procedure Qualification Testing,” August 2004

• DMS-10101, “Computer Equipment,” September 2006

• Society for Protective Coatings (SSPC)-SP 1, “Solvent Cleaning,” November 1, 1982

• SSPC-SP 2, “Hand Tool Cleaning.” November 1, 1982

• SSPC-SP 3, “Power Tool Cleaning,” November 1, 1982

• SSPC-SP 6, “Commercial Blast Cleaning,” January 1, 2007

• SSPC-SP 7, “Brush-off Blast Cleaning,” January 1, 2007

1.2 GENERAL

In general, the Contractor shall fabricate and erect structural steel and other metals used for steel structures or for steel portions of structures.

PART 2 – MATERIALS & EQUIPMENT

2.1 MATERIALS

A. Base Metal. The Contractor shall use metal that meets SPECIFICATION 60 42 00, “Metal for Structures.”

B. Compliance-confirmed Electrodes and Flux-Electrode Combinations. The Contractor shall use only electrodes and flux–electrode combinations found on the list of approved electrodes and flux–electrode combinations maintained by the Texas Department of Transportation (TxDOT).

To request that a product be added to this list or to renew an expired approval, submit certified reports of all tests required by the applicable AWS A5 specification according to the applicable welding code (for most construction, AASHTO/AWS D1.5, Bridge Welding Code, or AWS D1.1, Structural Welding Code—Steel) to the Government.

USIBWC Contract No.: IBM09B0004 Page 60.41.00 - 3

C. High-Strength Bolts. The Contractor shall use high-strength bolts as required in the plans.

D. Coatings. The Contractor shall use provide coating materials, as required, in accordance with SPECIFICAITON 60 45 00, “Galvanizing,” and required in the plans.

2.1 EQUIPMENT (No Requirements Defined for this Specification)

PART 3 – CONSTRUCTION METHODS

3.1 GENERAL REQUIREMENTS

A. Applicable Codes. The Contractor shall perform all fabrication in accordance with AASHTO/NSBA Steel Bridge Collaboration S2.1, including fabrication of non-bridge members.

Follow all applicable provisions of the appropriate AWS Code (D1.5 or D1.1) except as otherwise noted in the plans or in this Specificaton. Weld sheet steel (thinner than one-eighth (1/8) inch) in accordance with ANSI/AWS D1.3, Structural Welding Code—Sheet Steel. Unless otherwise stated, requirements of this Item are in addition to the requirements of S2.1.

B. Primary Members. Primary members include:

• webs and flanges of plate, tub, and box girders;

• rolled beams and cover plates;

• floor beam webs and flanges;

• arch ribs and arch tie beams or girders;

• truss members;

• diaphragm members for curved plate girders or beams;

• pier diaphragm members for tub girders;

• splice plates for primary members; and

• any other member designated as “primary” or “main” on the plans.

C. Responsibility. The Contractor is responsible for the correctness and completeness of shop drawings and for the fit of shop and field connections.

D. Qualification of Plant, Laboratories, and Personnel.

(1) Fabrication. Plants must be qualified in accordance with S2.1 (or equal acceptable qualification). When American Institute of Steel Construction (AISC) certification is required, the Contractor shall provide a copy of the certificate and a copy of the complete audit report, including the exit meeting report.

(2) Non-destructive Examination (NDE). Personnel performing NDE must be qualified in

USIBWC Contract No.: IBM09B0004 Page 60.41.00 - 4 accordance with the applicable AWS Code.

(3) Welding Procedure Qualification. Laboratories performing testing for welding procedure qualification must successfully complete periodic audits in accordance with DMS-7360, “Qualification Procedure for Laboratories Performing Welding Procedure Qualification Testing.”

E. Drawings.

(1) Erection Drawings. The Contractor shall submit two (2) copies of erection drawings before erection as required on the plans; submit an additional copy of the drawings for railroad underpasses; clearly indicate at least:

• procedures;

• sequence of work;

• equipment to be used;

• location of falsework, erection cranes, and holding cranes;

• falsework design details;

• girder lifting points;

• adjacent structures loaded; and

• requirements for releasing cranes during erection that differ from the requirements of this Item or those shown on the plans.

If site conditions differ from those assumed for these drawings, the Contractor shall revise the drawings to reflect the actual conditions before continuing the erection work.

(2) Shop Drawings. Before fabrication, the Contractor shall prepare and submit shop drawings for each detail of the general plans requiring the use of structural steel, forgings, wrought iron, or castings.

(3) Non-Bridge Structures. The Contractor shall prepare clear and legible shop drawings for the complete assembly on sheets, 11 inches x 17 inches. Full-size drawings may be reduced to half-scale size if they are clear and legible. At the left end, the Contractor shall provide a 1-1/2-inch margin, with the other margins ½-inch wide; indicate joint details on shop drawings for all welds; provide a title block on each sheet in the lower right corner with the following information:

• sheet index data shown on the lower right corner of the project plans,

• sheet numbering for the shop drawings,

• name of the fabricator, and

• name of the Contractor.

USIBWC Contract No.: IBM09B0004 Page 60.41.00 - 5

The Contractor shall furnish seven (7) copies of completed shop drawings to the Government.

F. Welding and Fabrication Procedures.

(1) Welding Procedures. Before fabrication begins, the Contractor shall submit welding procedures in accordance with the applicable AWS Code to the Government, Materials and Pavements Section, and notify the COR which procedures will be used for each joint or joint type. Post the compliance-confirmed welding procedure specification for the welding being performed on each welding machine, or use another compliance-confirmed method of ensuring that the welder has access to the procedure information at all times.

(2) Fabrication Procedures. When primary bridge members are fabricated by welding or bolting, submit a fabrication procedure before fabrication begins. The fabrication procedure must include details required by S2.1 as well as:

• special processes such as planing or facing,

• details of heat treating and heat straightening procedures, and

• any other information required by the Government.

Have a fabrication procedure compliance-confirmed for each type of structure (rolled beams with welded or bolted splices, plate girders with welded or bolted splices, tub girders with welded or bolted splices, box girders, plate girder bents, railroad thru-girders and plate girders, truss bridges, orthotropic deck segments, or other major bridge structure types) before starting fabrication.

G. Submerged-Arc Welding (SAW). The Contractor shall provide equipment with automatic guidance capable of maintaining the position of the arc and controlling the speed of travel so that, when once set by the operator, little manipulation is needed. Small adjustments to compensate for acceptable plate waviness, acceptable tilt of flange, etc. will be permitted. Do not use hand-held semiautomatic SAW for welding bridge members unless altered to provide automatic guidance or otherwise compliance-confirmed.

H. Inspection. The Contractor shall provide the COR with the helpers and equipment needed to move material to allow inspection. QC is solely the responsibility of the Contractor. The Contractor must have a QC staff qualified in accordance with the applicable AWS Code. The QC staff must provide inspection of all materials and workmanship prior to inspection by the Government.

I. Documentation. Before beginning fabrication, the Contractor shall provide supporting documentation (such as mill test reports), issued by the producing mill and verified by qualified personnel; ensure that the documentation legibly reflects all information required by the applicable ASTM specifications. As material is shipped or placed in compliance-confirmed storage, the Contractor shall provide a copy of the shipping or storage invoice that reflects:

• member piece mark identification and calculated weight per piece from the contract drawings, USIBWC Contract No.: IBM09B0004 Page 60.41.00 - 6

• number of pieces shipped or in storage,

• total calculated weight for each invoice per bid item, and

• the unique identification number of the shipping or storage invoice.

The acceptance of material or finished members by the Inspector will not prohibit subsequent rejection if the material or members are found to be damaged or defective. Replace rejected material promptly.

J. Material Identification. Assembly-mark individual pieces and issue cutting instructions to the shop using a system that will maintain identity of the original piece; identify structural steel by standard and grade of steel. Also differentiate between material toughness requirements (CVN, fracture-critical) as well as any other special physical requirements. In addition, identify structural steel for primary members by mill identification numbers (heat numbers). Use an compliance-confirmed identification system. Use either paint or low-stress stencils to make identification markings on the metal. Mark the material as soon as it enters the shop and carry the markings on all pieces through final fabrication. Transfer the markings before cutting steel for primary members of bridge structures into smaller pieces. Loss of identification marking on any piece, with no other positive identification, or loss of heat number identification on any primary member piece will render the piece unacceptable for use. Unidentifiable material may be compliance-confirmed for use after testing to establish acceptability to the satisfaction of the Government. Have testing performed by an compliance-confirmed testing facility, and have results signed and sealed by a licensed professional engineer.

3.2 WELDING

A. Details. The Contractor shall perform the following as required in the plans:

(1) Rolled Edges - Trim plates with rolled edges used for webs by thermal cutting.

(2) Weld Tabs - Use weld tabs at least two (2) inches long for manual and semi-automatic processes and at least three (3) inches long for automatic processes, and in all cases at least as long as the thickness of the material being welded; use longer weld tabs as required for satisfactory work.

(3) Weld Termination - Terminate fillet welds approximately one-quarter (1/4) inch from the end of the attachment except for galvanized structures and flange-to-web welds, for which the fillet weld must run the full length of the attachment unless otherwise noted on the plans.

(4) No-Paint Areas at Field-Welded Connections - Keep surfaces within four (4) inches of groove welds or within two (2) inches of fillet welds free from shop paint.

(5) Galvanized Assemblies - Completely seal all edges of tightly contacting surfaces by welding before galvanizing.

B. Shop Splices. The Contractor shall perform the following as required in the plans:

USIBWC Contract No.: IBM09B0004 Page 60.41.00 - 7

(1) Shop Splice Locations - Keep at least six (6) inches between shop splices and stiffeners or crossframes and at least six (6) inches between web and flange shop splices; do not add optional splices to plates shown on the plans as forty (40) feet long or shorter unless necessary to obtain the required geometry or otherwise compliance-confirmed; obtain compliance-confirmation for shop splices added after shop drawings are compliance-confirmed.

(a) Continuous Multiple-Span Structures - Unless otherwise shown on the plans or compliance-confirmed, do not locate tension flange splices within 0.05S of an interior bearing, within 0.10S of the centerline of an interior span, or between 0.30S and 0.50S from an end bearing, where S is the span length between centers of bearings.

(b) Single-Span Structures. Unless otherwise shown on the plans or compliance-confirmed, do not locate tension flange splices within 0.10S of the centerline of the span.

(2) Grinding Splice Welds - Grind shop groove welds in flange plates smooth and flush with the base metal on all surfaces whether the joined parts are of equal thickness or of unequal thickness; grind so that the finished grinding marks run in the direction of stress, and keep the metal below the blue brittle range (below three hundred fifty degrees Fahrenheit (350°F)); groove welds in web plates, except at locations of intersecting welds, need not be ground unless shown on the plans except as required to meet AWS welding code requirements.

C. Joint Restraint. The Contractor shall never restrain a joint on both sides when welding.

D. Stiffener Installation. The Contractor shall perform the following as required in the plans:

(1) Flange Tilt - Members must meet combined tilt and warpage tolerances before the installation of stiffeners; cut stiffeners to fit acceptable flange tilt and cupping; minor jacking or hammering that does not permanently deform the material will be permitted.

(2) Stiffeners Near Field Splices - Tack-weld intermediate stiffeners within twelve (12) inches of a welded field splice point in the shop; weld the stiffeners in the field in accordance with SPECIFICAITON 60 48 00, “Structural Field Welding,” after the splice is made.

E. Nondestructive Examination (NDE). The Contractor shall perform magnetic particle testing

(MT), radiographic testing (RT), and ultrasonic testing (UT) at the Contractor’s expense as specified in AWS Code D1.5 for bridge structures and AWS Code D1.1 for all other welding.

The Government will periodically witness, examine, verify, and interpret NDE. Additional welds may be designated for NDE on the plans. Retest repaired groove welds per the applicable AWS Code after repairs are made and have cooled to ambient temperature. Complete NDE and repairs before assembly of parts into a member but after any heat-correction of weld distortion.

(1) Radiographic Testing - Radiographs must have a density of at least two and five-tenths (2.5) and at most three and five-tenths (3.5), as confirmed by a radiographer. The density in any single radiograph showing a continuous area of constant thickness must not vary in this area by more than five-tenths (0.5). Use only ASTM System Class I radiographic film as

USIBWC Contract No.: IBM09B0004 Page 60.41.00 - 8 described in ASTM E1815. Use low-stress stencils or other acceptable means to make radiograph and location identification marks on the steel. The Government will examine and interpret all results of RT.

(2) Ultrasonic Testing - Have UT equipment calibrated yearly by an authorized representative of the equipment manufacturer or by an compliance-confirmed testing laboratory.

(3) Magnetic Particle Testing - Orient the prod or pole position normal or parallel to the weld unless otherwise compliance-confirmed. When using the yoke method, use half-wave rectified DC unless otherwise compliance-confirmed.

(4) Extra-high Strength Steel - For shop welds on steel that has a nominal yield strength over seventy-thousand (70,000) pounds per square inch (psi), perform RT on all flange and web splices in addition to any requirements of the applicable AWS Code. Wait at least forty-eight

(48) hours after completing these welds before inspecting them.

F. Testing of Galvanized Weldments. If problems develop during galvanizing of welded material, the Government may require a test of the compatibility of the combined galvanizing and welding procedures in accordance with this Specification and may require modification of one or both of the galvanizing and welding procedures. If testing is required, prepare a test specimen with a minimum length of twelve (12) inches using the same base material, having the same joint configuration, and using the welding procedure proposed for production work. Clean and galvanize this test specimen using the same conditions and procedure that will be applied to the production galvanizing. After galvanizing, examine the test specimen. There must be no evidence of excessive buildup of zinc coating over the weld area. Excessive zinc coating buildup will require modification of the galvanizing procedure. Remove the zinc from the weld area of the test specimen in accordance with ASTM A90, and visually examine the weld area. There must be no evidence of loss of weld metal or any deterioration of the base metal due to the galvanizing or welding procedure. If there is evidence of deterioration or loss of weld metal, modify the galvanizing or welding procedure as required and run a satisfactory retest on the modified procedures before production work. Report procedures and results on the galvanized weldment worksheet provided by the Government.

3.3 BOLT HOLES

The Contractor shall detail holes on shop drawings one-sixteenth (1/16) inch larger in diameter than the nominal bolt size shown on the plans unless another hole size is shown on the plans; thoroughly clean the contact surfaces of connection parts in accordance with Part 3.1, “General,” before assembling them for hole fabrication; make holes in primary members full-size (by reaming from a subsize hole, drilling full-size, or punching full-size where permissible) only in assembly unless otherwise compliance-confirmed.

Ream and drill with twist drills guided by mechanical means unless otherwise compliance-confirmed. If sub-punching holes, punch them at least three-sixteenth (3/16) inch smaller than the nominal bolt size.

When numerically controlled (N/C) equipment is used, submit for compliance-confirmation the proposed procedures to accomplish the work from initial drilling or punching through check assembly. Use thermal cutting for holes only with permission of the Government. Permission for thermal cutting is not required for making slotted holes, when slotted holes are shown on the plans, by drilling or punching two holes and then thermally cutting the straight portion between them. Perform all thermal cutting in

USIBWC Contract No.: IBM09B0004 Page 60.41.00 - 9 accordance with Part 3.5.A, “Thermal Cutting.” Slightly conical holes that naturally result from punching operations are acceptable provided they do not exceed the tolerances of S2.1. The tolerance for anchor bolt hole diameter for bridge bearing assemblies is +1/8 inch, −0.

3.4 DIMENSIONAL TOLERANCES

The Contractor shall meet tolerances of the applicable AWS specifications and S2.1 except as modified in this Specification.

A. Rolled Sections - Use ASTM A 6 mill tolerances for rolled sections, except that AWS Code D1.5 camber tolerances apply to rolled sections with a specified camber.

B. Flange Straightness - Ensure that flanges of completed girders are free of kinks, short bends, and waviness that depart from straightness or the specified camber by more than one-eighth (1/8) inch in any ten (10) feet along the flange. Rolled material must meet this straightness requirement before being laid off or worked. Plates must meet this requirement before assembly into a member. After straightening a bend or buckle, inspect the surface of the metal for evidence of fracture. The Government may require nondestructive testing.

C. Alignment of Deep Webs in Welded Field Connections - For girders forty-eight (48) inches deep or deeper, the webs may be slightly restrained while checking compliance with tolerances of S2.1.

In the unrestrained condition, webs forty-eight (48) inches deep or deeper must meet the tolerances of Table 1. Girders under forty-eight (48) inches deep must meet the alignment tolerances of S2.1.

Table 1 Web Alignment Tolerances for Deep Girders

Web Depth (in.) Maximum Web Misalignment (in.)

48 1/16 60 1/8 72 1/4 84 5/16 96 5/16 108 3/8 120 7/16 132 7/16 144 1/2

D. Bearings - Correct bearing areas of shoes, beams, and girders using heat, external pressure, or both. Grind or mill only if the actual thickness of the member is not reduced by more than one-sixteenth (1/16) inch below the required thickness.

(1) I-Beams, Plate Girders, and Tub Girders - The plane of the bearing area of beams and girders must be perpendicular to the vertical axis of the member within one-sixteenth (1/16) inch in any twenty-four (24) inches.

USIBWC Contract No.: IBM09B0004 Page 60.41.00 - 10

(2) Closed Box Girders - Meet these tolerances:

• The plane of the bearing areas of the box girder is perpendicular to the vertical axis of the girder within one-sixteenth (1/16) inch across any horizontal dimension of the bearing.

• The planes of the beam supports on the box girder are true to the vertical axis of the supported beams or girders to one-sixteenth (1/16) inch in any twenty-four (24 ) inches.

In the shop, verify the plane of all bearing areas with the box placed on its bearings to field grade, using an compliance-confirmed process for verification.

(3) Shoes - Meet these tolerances:

• The top bolster has the center seventy-five percent (75%) of the long dimension (transverse to the girder) true to one-thirty-second (1/32) inch, with the remainder true to one-sixteenth (1/16) inch, and is true to one-thirty-second (1/32) inch across its entire width in the short dimension (longitudinal to the girder).

• The bottom bolster is true to one-sixteenth (1/16) inch across its diagonals.

E. End Connection Angles - For floor beams and girders with end connection angles, the tolerance for the length back to back of connection angles is ±1/32 in. If end connections are faced, do not reduce the finished thickness of the angles below that shown on the shop drawings.

3.5 OTHER FABRICATION PROCESSES

A. Thermal Cutting - Use a mechanical guide to obtain a true profile; hand-cut only where compliance-confirmed. Hand-cutting of radii for beam copes, weld access holes, and width transitions is permitted if acceptable profile and finish are produced by grinding. Provide a surface finish on thermal-cut surfaces, including holes, in accordance with AWS Code D1.5 requirements for base metal preparation. Obtain compliance-confirmation before using other cutting processes.

B. Oxygen-Gouging - Do not oxygen-gouge ASTM A588 or A709 Gr. 50W steel or material with nominal yield strength over seventy (70) kips per square inch (ksi).

C. Annealing and Normalizing - Complete all annealing or normalizing (as defined in ASTM A941) before finished machining, boring, and straightening; maintain the temperature uniformly throughout the furnace during heating and cooling so that the range of temperatures at all points on the member is no greater than one hundred degrees Fahrenheit (100°F).

D. Machining - Machine the surfaces of expansion bearings so that the travel direction of the tool is in the direction of expansion.

E. Camber - Complete cambering in accordance with AWS Code S2.1 before any heat-curving.

F. Heat Curving - Heat-curve in accordance with AWS Code S2.1. The methods in the AASHTO

USIBWC Contract No.: IBM09B0004 Page 60.41.00 - 11 bridge construction specifications are recommended. Attach cover plates to rolled beams before heat-curving only if the total thickness of one flange and cover plate is less than two and one-half (2-1/2) inches and the radius of curvature is greater than one thousand (1,000) feet. For other rolled beams, attach cover plates only after heat-curving is completed. Locate and attach connection plates, diaphragm stiffeners, and bearing stiffeners after curving, unless girder shrinkage is accounted for.

G. Bending of Quenched and Tempered Steels - The cold-bending radius limitations for HPS 70W in

AWS Code S2.1 apply to all quenched and tempered steels.

3.6 NONCONFORMANCE REPORTS (NCR)

When the requirements of this Specification are not met, submit an NCR to the Government for compliance-confirmation; include on the NCR:

• date of submittal, nonconformance report number, and IFM number (when applicable);

• project information (county; project number; shop order number; structure name, etc.);

• member identification (member number, or piece or erection mark);

• description of problem including references to sections of specifications not met;

• explanation of why the problem occurred and plan for preventing future occurrences (if applicable);

• detailed description (including drawings) of proposed solution including a repair proposal; and

• diagrams detailing all pertinent dimensions and locations on relevant sections of shop drawings, including title blocks.

Do not begin repairs before compliance-confirmation is received. Perform all repair work in strict compliance with the compliance-confirmed repair procedure.

3.7 SHOP ASSEMBLY

A. General Shop Assembly. Shop-assemble field connections of primary members of trusses, arches, continuous beam spans, bents, towers (each face), plate girders, field connections of floor beams and stringers (including for railroad structures), field-bolted diaphragms for curved plate girders and railroad underpasses, and rigid frames. Complete fabrication, welding (except for shear studs), and field splice preparation before members are removed from shop assembly.

Obtain compliance-confirmation for any deviation from this procedure. The Contractor is responsible for accurate geometry. Use a method and details of preassembly consistent with the erection procedure shown on the erection plans and camber diagrams. The sequence of assembly may start from any location in the structure and proceed in one or both directions. An compliance-confirmed method of sequential geometry control is required unless the full length of

USIBWC Contract No.: IBM09B0004 Page 60.41.00 - 12 the structure is assembled. Verify by shop assembly the fit of all bolted and welded field connections between bent cap girders and plate girders or between plate girders and floor beams.

Do not measure horizontal curvature and vertical camber for final acceptance until all welding and heating operations are completed and the steel has cooled to a uniform temperature. Check horizontal curvature and vertical camber in a no-load condition.

B. Bolted Field Connections. Each shop assembly, including camber, alignment, accuracy of holes, and fit of milled joints, must be compliance-confirmed before the assembly is dismantled.

Assemble with milled ends of compression members in full bearing. Assemble non-bearing connections to the specified gap. Ream all subsize holes to the specified size while the connections are assembled, or drill full size while the connections are assembled. Notify the Government before shipping if fill plates or shims are added. Adding or increasing the thickness of shims or fill plates in bearing connections requires compliance-confirmation. Use drift pins and snug-tight bolts during the drilling process to ensure that all planes of the connection (webs and flanges) can be assembled simultaneously. Do not use tack welds to secure plates while drilling. If parts are not completely bolted in the shop, secure them by temporary bolts to prevent damage in shipment and handling. Never use tack welds in place of temporary bolts. Match-mark connecting parts in field connections using low-stress stencils in accordance with the diagram in the erection drawings.

C. Welded Field Connections. Mill or grind bevels for groove welds. Do not cut into the web when cutting the flange bevel adjacent to the web. End preparation, backing, and tolerances for single-V groove welds for framing beams or girders must conform to the applicable AWS Code unless otherwise shown on the plans. In the shop, prepare ends of beams or girders to be field-welded taking into account their relative positions in the finished structure due to grade, camber, and curvature. Completely shop-assemble and check each splice. While the splice is assembled, match-mark it with low-stress stencils in accordance with the diagram in the erection drawings.

3.8 FINISHING AND PAINTING

A. Shop Painting. On new steel items to be painted (except for the coatings on box and tub girder interiors), grind corners that are sharp or that form essentially ninety degree (90º) angles to an approximately one-sixteenth (1/16)-inch flat surface before blast cleaning. (A corner is the intersection of two plane faces.) This requirement does not apply to punched or drilled holes. Do not omit shop paint to preserve original markings.

B. Bearing and Faying Surfaces. Clean and prepare all bearing and faying surfaces of bolted connections before shipment.

C. Girder Interiors. Paint the inside of all box and tub girders in accordance with applicable provision of SPECIFICATION 60 46 00, “Cleaning and Painting Steel.”

D. Weathering Steel. Provide an SSPC-SP 6 blast in the shop to all fascia surfaces of unpainted weathering steel beams. Fascia surfaces include:

• exterior sides of outermost webs and undersides of bottom flanges of plate girders and

USIBWC Contract No.: IBM09B0004 Page 60.41.00 - 13 rolled beams,

• all outer surfaces of tub girders and box girders,

• all surfaces of truss members,

• webs and undersides of bottom flanges of plate diaphragms,

• bottom surfaces of floor beams, and

• any other surfaces designated as “fascia” on the plans.

Do not mark fascia surfaces. Use one of the following methods as soon as possible to remove any markings or any other foreign material that adheres to the steel during fabrication and that could inhibit the formation of oxide film:

• SSPC-SP 1, “Solvent Cleaning”

• SSPC-SP 2, “Hand Tool Cleaning”

• SSPC-SP 3, “Power Tool Cleaning”

• SSPC-SP 7, “Brush-off Blast Cleaning”

Do not use acids to remove stains or scales. Feather out touched-up areas over several feet.

E. Machined Surfaces. Clean and coat machine-finished surfaces that are in sliding contact, particularly pins and pinholes, with a non-drying, water-repellent grease-type material containing rust-inhibitive compounds. Ensure that the coating material contains no ingredients that might damage the steel. Protect machined surfaces from abrasive blasting.

3.9 HANDLING AND STORAGE OF MATERIALS

The Contractor shall prevent damage when storing or handling girders or other materials. If damage to material is caused by handling devices or improper storage, remove or repair the material by acceptable means in accordance with ASTM A6 and the applicable AWS Code. Place stored materials on skids or acceptable dunnage above the ground. Keep materials clean. Shore girders and beams to keep them upright and free of standing water. Place support skids close enough to prevent excessive deflection in long members such as columns. Do not stack completed girders or beams at the jobsite. Protect structural steel from salt water or other corrosive environments during storage and transit.

3.10 HANDLING AND STORAGE OF MATERIALS

The Contractor shall mark all structural members in accordance with the erection drawings. If a surface is painted, make the marks over the paint. Do not use impact-applied stencils to mark painted surfaces.

Mark the weight directly on all members weighing more than three (3) tons. Keep material clean and free from injury during loading, transportation, unloading, and storage. Pack bolts of each length and diameter, and loose nuts or washers of each size, separately and ship them in boxes, crates, kegs, or barrels. Plainly mark a list and description of the contents on the outside of each package.

3.11 FIELD ERECTION

USIBWC Contract No.: IBM09B0004 Page 60.41.00 - 14

A. Methods and Equipment. The Contractor shall not tack-weld parts instead of using erection bolts, and shall not tack-weld parts to hold them in place for bolting. The Contractor shall provide falsework, tools, machinery, and appliances, including drift pins and erection bolts; provide enough drift pins, 1/32 inch larger than the connection bolts, to fill at least one-quarter (1/4) of the bolt holes for primary connections. Use erection bolts of the same diameter as the connection bolts. Securely tie, brace, or shore steel beams or girders immediately after erection as shown on the plans and the erection drawings. Maintain this bracing or shoring until the diaphragms are in place. Protect railroad or roadway traffic that may be beneath erected girders or beams from falling objects during erection of the members and diaphragms, placement of the deck concrete, and erection and removal of forms. Use nets or flooring with openings no larger than one (1) inch for this protection.

B. Falsework. The Contractor shall design and construct falsework for the anticipated loads, including wind, and properly maintain this falsework.

C. Handling and Assembly. The Contractor shall accurately assemble all parts as shown on the plans and the compliance-confirmed shop drawings; verify match-marks; handle parts carefully to prevent bending or other damage; do not hammer if doing so damages or distorts members; do not weld any member for transportation or erection unless noted on the plans or compliance-confirmed by the Government.

(1) Welded Connections. Before releasing the erection cranes, weld flange splices to fifty percent (50%) of their thickness and meet the minimum erection bracing and support requirements shown on the plans and on the submitted erection plans; field-weld in accordance with SPECIFICATION 60 48 00, “Structural Field Welding.”

(2) Bolted Connections. Before releasing the erection cranes:

• install fifty percent (50%) of the bolts in the top and bottom flanges and the web with all nuts finger-tight,

• meet the minimum erection bracing and support requirements shown on the plans and on the submitted erection plans, and

• for tub girders, install top lateral bracing across the connection and fully tension the bolts connecting the bracing to the top flanges.

Install high-strength bolts, including erection bolts, in accordance with SPECIFICATION 60 47 00, “Structural Bolting.” Clean bearing and faying surfaces for bolted connections in accordance with SPECIFICATION 60 47 00, “Structural Bolting.” Clean the areas of the outside ply under washers, nuts, and bolt heads before bolt installation. Ensure that the required faying surface condition is present at the time of bolting.

D. Misfits. The Contractor shall correct minor misfits. Ream no more than ten percent (10%) of the holes in a plate connection (flange or web), and ensure that no single hole is more than one-eighth (1/8) inch larger than the nominal bolt diameter. Submit proposed correction methods for members with defects that exceed these limits or that prevent the proper assembly of parts.

USIBWC Contract No.: IBM09B0004 Page 60.41.00 - 15

Straighten structural members in accordance with AWS Code S2.1. Make all corrections in the presence of the Government at no expense to the Government. Do not remove and re-weld gusset plates without compliance-confirmation.

E. Bearing and Anchorage Devices. The Contractor shall place all bearing devices such as elastomeric pads, castings, bearing plates, or shoes on properly finished bearing areas with full and even bearing on the concrete. Place metallic bearing devices on one-quarter (1/4)-inch-thick preformed fabric pads. Provide holes in the pad that are no more than one-quarter (1/4)-inch larger than the bolt diameter. When the concrete bearing area has been placed below grade, build it up to the correct elevation using mortar that meets SPECIFICATION 60 20 00, “Concrete Structures,” and provide adequate curing. For buildups between one-eighth (1/8) inch and three-eighths (3/8) inch thick; use only mortar. If the bearing area must be raised more than three-eighths (3/8) inch, use galvanized steel shims or other compliance-confirmed shim materials in conjunction with mortar. Provide at least seventy-five percent (75%) contact of flange to shoe with no separation greater than 1/32 inch for beams and girders. Make corrections using heat or pressure in accordance with S2.1, or with galvanized shims. Correct small irregularities by grinding. Provide at least eighty-five percent (85%) contact between the rocker plate and the base plate. Adjust the location of slotted holes in expansion bearings for the prevailing temperature.

Adjust the nuts on the anchor bolts at the expansion ends of spans to permit free movement of the span. Provide lock nuts or burr the threads. Remove all foreign matter from sliding or machine-finished surfaces before placing them in the structure. Restore distorted bearing pads or expansion bearings to an equivalent seventy degrees Fahrenheit (70ºF) position after completion of all welded or bolted splices, using an compliance-confirmed method of relieving the load on the bearing devices.

F. Erecting Forms. The Contractor shall not erect forms until all welding or bolting is complete and the unit is positioned and properly set on the bearing unless otherwise noted on the plans.

G. Field Finish. The Contractor shall paint in accordance with requirements in the plans. For weathering steel that will remain unpainted, after all welding and slab concrete placement has been completed, restore the steel to a uniform appearance by solvent cleaning, hand cleaning, power brush, or blast cleaning. As soon as possible, remove from all unpainted weathering steel fascia surfaces any foreign material, including markings, that adheres to the steel and could inhibit formation of oxide film. Feather out touched-up areas over several feet. Do not use acids to remove stains or scales.

PART 4 – MEASUREMENT AND PAYMENT

The work performed by the Contractor under this specification shall not be paid for directly, but shall be considered subsidiary to the various Bid Items under this Contract.

- END OF SPECIFICATION -

USIBWC Contract No.: IBM09B0004 Page 60.41.00 - 16

This Page Intentionally Blank