556.01 Description
This work is the furnishing, fabricating, painting, and erecting of steel structures and the steel structure portions of composite structures. The Department uses 490 pounds per cubic foot (7,850 kg/m3) to calculate the weight of structural steel. The weights of rolled shapes and plates up to and including 36 inches (915 mm) in width are computed based on their nominal weights and dimensions as shown on the shop drawings. One- half of the allowed percentage of overrun in weight as tabulated in ASTM A6 will be added to the nominal weights of plates exceeding 36 inches (915 mm) in width. The weight is computed on the basis of rectangular dimensions for all plates and overall lengths for all structural shapes with no deductions for copes, slips, sheared edges, punching, borings, milling, or planing. When parts can be economically cut in multiples from materials of larger dimension, the calculated weight is that of the material from which the parts are cut. Bolts, nuts, and washer weights are the calculated weight in the AISC Manual of Steel Construction. Weld metal weight is not computed.
556.02 Materials
Furnish materials in accordance with the following subsection requirements: Bearing Assembly Anchor Bolts for Bridges ............ 711.13 Bolts and Nuts ......................................................... 711.07 Castings .................................................................. 711.12 Compression Joint Seals ......................................... 711.15 Elastomeric Bearing Devices................................... 711.14 Fiber-reinforced Pads for Bearing Plates ................. 711.16 Galvanized Metal .................................................... 711.08 High Strength Bolts ................................................. 711.06 Pins and Rollers ...................................................... 711.04 Structural Steel........................................................ 711.02 Structural Steel Tubing ............................................ 711.03 Welding Electrodes ................................................. 711.05 Welded Stud Shear Connectors .............................. 711.09
556.03 Construction Requirements
For the fabrication of steel structures, follow AASHTO LRFD Bridge Construction Specifications, unless otherwise specified in the contract.
556.03.1 Pre-Qualification for Steel Fabricators
Use metal fabricators that are pre-qualified under the AISC Quality Certification Program for the items listed below. The Department will make an exemption for new manufacturing plants that are of the same ownership as an existing certified plant, provided the new manufacturing plant operates under the same quality assurance and control programs as the certified plants, modified to address any production differences, and all fabrication is performed under the direct supervision of a quality assurance and control manager provided by an existing pre-qualified plant. Direct supervision means that the quality assurance and control manager is on site during all fabrication performed in the new fabrication plant and is responsible for the quality assurance 556 – STEEL STRUCTURES 2020 EDITION V5.1 556-2 and control activities. For new manufacturing plants, submit and receive approval of any proposed modifications to the parent plant’s quality assurance and control program prior to beginning production. Allow 30 business days from the date submitted for Department review and approval. New manufacturing plants may operate under the parent plant’s quality assurance and control programs for a maximum of 18 months from the date of opening. Plants currently operating under this exemption may do so only until January 1, 2016. Items not listed may be fabricated by non-certified shops. Use metal fabricators having the following AISC quality certification categories:
1.Use fabricators having Advanced Bridges (ABR) certification to fabricate the following:
a.Fracture critical members and attachments. Fabricators must have the fracture critical endorsement (F).
b.Tub, trapezoidal or closed box girders, large or non-preassembled trusses [over 200 feet (60 m)], cable supported bridges, bascule bridges, arches, and bridges with tight radius.
2.Use fabricators having Intermediate Bridges (IBR) certification to fabricate the following:
a.Fracture critical members and attachments. Fabricators must have the Fracture Critical Endorsement (F).
b.Rolled beams with field or shop splices, either straight or with a radius over 500 ft.
c.Built-up I-shaped plate girders with constant depth, either straight or with a radius over 500 feet (150 m).
d.Built-up I-shaped plate girders with variable web depth (e.g., haunched), either straight or with a radius over 1000 feet (305 m).
e.A truss with a length of 200 feet (60 m) or less that is entirely or substantially pre- assembles at a certified facility and shipped in no more than three sub-assemblies.
f.Welded floor beams.
g.Diaphragms for horizontally curved girders.
3.Use fabricators having Simple Bridges (SBR) certification to fabricate the following:
a.Non-spliced rolled beams.
b.Non-spliced rolled floor beams.
c.Non-spliced rolled diaphragms for straight girders (does not include diaphragms used for concrete beams).
4.Use fabricators having an SBR or Bridge and Highway Metal Component Manufacturers certification to fabricate the following:
a.Bridge expansion joints.
b.Steel grid decking.
c.Bridge expansion bearings.
d.Overhead sign bridge and cantilever sign structures.
e.Lighting poles and anchor bases.
556.03.2 Submittals
A.Fabrication Drawings. Prior to fabricating members, submit fabrication drawings and include the following information:
1.An erection layout with each member assigned a production number.
2.A tentative fabrication schedule.
3.Denote any changes from the details in the contract.
4.All dimensions, geometrical information, details, and other data required for fabrication. Include camber information, blocking diagrams and shop splices. 2020 EDITION V5.1 STEEL STRUCTURES – 556 556-3
5.Denote specification, grade, finish, required toughness testing and required surface preparation for all steel plates, shapes, pipes, tubes, bars, and all miscellaneous hardware such as shear studs, bolts, stud bolts, threaded rods, nuts, and washers.
7.A list of field bolts and other items furnished by the fabricator:
8.Appropriate weld sizes, symbols, requirements for non-destructive testing, heat cambering and bending procedures. Provide welding certifications and welding procedure specifications and any supporting documentation for all welding required for fabrication. For welding requirements see Section 624 ; and
9.Welding Procedure Specification (WPS) identification is required in the weld symbol tail for all weld symbols shown on the shop drawings. Submit shop drawings of welding procedures and design calculations. Ensure the submittal includes all information required to check the structural accuracy and fabrication procedures for the structure. Structural shop drawings must be designed and stamped by a professional engineer registered and licensed to conduct engineering in the State of Montana. Do not begin fabrication until the Department approved drawings are received by both the plant and the Department Inspector. Coordinate the fabrication schedule with the Department Inspector.
B.Certificate of Compliance. Furnish a manufacturer’s Certificate of Compliance for all bolts, nuts, washers, and load indicator washers. Include documentation in accordance with Subsection 106.09 and test reports performed on the finished bolt confirming that all of the materials provided meet the requirements of the applicable AASHTO or ASTM specification. The documentation must include the name and address of the test laboratory, the date of testing, lot identification and the sample sizes of bolts and nuts used for each test performed for the certification. Submit the following items before installation:
1.The certification from the supplier showing that all tests required by the AASHTO and ASTM specifications have been performed. Include the date and location of those tests, as well as the production lot numbers, and the sample sizes used for each test performed with the certification.
2.The certification from the supplier, showing that the wedge tests and rotational capacity tests have been performed. Also show production lot numbers, dates, locations, and sample sizes of these tests and who performed them.
3.Three bolt, nut, and washer assemblies from each rotational capacity test lot for verification by the Department. Do not install fasteners prior to receiving approval.
556.03.3 Mill and Shop Inspection
1.Inspection of Work. Do not begin manufacturing or shop fabrication until the Department’s Inspector has inspected the shop.
2.Facilities for Inspection. Furnish facilities for inspecting the material and workmanship in the mill and shop. Always allow the Inspector free access to the work.
3.Inspector’s Authority. The Inspector may reject material or work not in accordance with the specifications. In case of dispute, the Contractor may appeal the Inspector’s decision to the Project Manager. 556 – STEEL STRUCTURES 2020 EDITION V5.1 556-4
4.Mill Test Reports. Furnish the Project Manager signed documentation in accordance with Subsection 106.09. Certify all steel meets the project specifications Identify each piece of steel with a mark number on the mill test report.
5.Facilities for Testing. Furnish, at Contractor expense, test specimens, labor, testing machines, and tools to make the specimens and tests.
6.Rejections. Material or finished members accepted by the Inspector may be rejected if the material is subsequently found defective. Replace or repair rejected material at Contractor expense.
556.03.4 Storage and Handling of Materials
Mark alloy and high-strength steels as required by the AASHTO LRFD Bridge Construction Specifications. Mark material required to meet a Charpy requirement for identification.
1.Store materials off the ground and keep them clean and dry.
2.Place and store girders upright.
3.Support long members, including but not limited to columns, chords, and girders on blocks spaced to prevent deflection.
4.Store high-strength fastener components in accordance with the manufacturer’s recommendations.
5.Store the bolts and nuts in the original containers until used.
6.Protect from dirt and moisture.
7.Remove only as many fasteners from protected storage as can be tightened during a work shift and return unused fasteners to protected storage at the end of each work shift.
556.03.5 Quality Control
Prepare and submit a quality control (QC) plan for ensuring the quality of all work and conformance to specifications. Ensure that all nondestructive testing (NDT) is performed by personnel qualified in conformance with the American Society for Nondestructive Testing (ASNT) Recommended Practice No. SNT-TC-1A to minimum Testing Level II for the individual methods. Ensure that the QC plan meets the following minimum requirements:
1.NDT, Radiographic Inspection. Inspect 100% of all complete joint penetration (CJP) groove welds.
2.NDT, Ultrasonic Inspection. Inspect 100% of all CJP groove welds on plates thicker than ¼-inch (6 mm).
3.NDT, Magnetic Particle Inspection. Randomly inspect 25% of all welding for each member throughout the entire structure in accordance with AWS D1.5 bridge welding code. The Project Manager reserves the right to select locations for testing.
4.Personnel qualifications. Include the qualifications of the specific individuals that will be performing the QC testing.
5.Quality control manager. Identify the QC manager that will be the primary contact person for all QC communication. Ensure that this person is responsible for all QC work.
6.NDT, Phased Array Ultrasonic Testing (PAUT). This method may be used in place of RT and UT for the inspection of CJP groove welds. Perform all aspects of PAUT inspection in accordance with AWS D1.5, Annex K. Provide, for approval, a submittal package 30 days prior to inspection. Provide all information, qualifications, etc. needed to determine the requirements of Annex K can be met. Include the inspector’s history of successful NDT projects specific to PAUT and the requirements of AWS D1.5. Provide reports of all QC testing as the testing is completed. Identify in the reports any deviations from specifications, standards, or the QC plan and a discussion of why the deviation occurred. 2020 EDITION V5.1 STEEL STRUCTURES – 556 556-5 At the completion of fabrication, and before shipment, provide a certification signed by the quality control manager that contains the following statement and supporting information: Required Statement: “This is to certify that the quality control plan was followed and that the results of the quality control program indicate that the materials and the construction operations controlled by the quality control plan are in conformity with the approved plans and specifications. Exceptions to the plans, specifications, and quality control plan are described below.”
556.03.6 Pilot and Driving Nuts.
Furnish 2 pilot nuts and 2 driving nuts for each size of pin unless otherwise specified. Pilot and driving nuts are not required when shoes are assembled at the fabrication plant.
556.03.7 Bolts and Bolted Connections
A.General. Make bolted connections in accordance with the contract requirements.
1.Furnish bolts that are free of rust.
2.When galvanized fasteners are specified, furnish assemblies manufactured with a visible dye, so a visual check verifies the lubricant’s presence at installation. Use black fasteners oily to the touch at installation.
3.Use beveled washers to provide full bearing to the head or nut where bolts are used on beveled surfaces.
B.Definitions.
1.Fastener Assembly. An assembly of fastener components including bolt, nut, washer, and DTI (when used) that are supplied, tested, and installed as a unit. A fastener assembly represents one diameter and grade from the same lot.
2.Snug-tight. The condition that exists when all plies in a connection have been pulled into firm contact by the bolts in the joint and bolts have been tightened sufficiently to prevent removal of the nuts without the use of a wrench.
3.Systematic Tightening. The systematic assembly of the joint, progressing from the most rigid part of the joint until the connected piles are in firm contact and the subsequent systematic tightening of all bolts in the joint, progressing from the most rigid part of the joint in a manner that will minimize relaxation of previously tightened bolts.
C.Unfinished Bolts. Furnish standard unfinished bolts; with nuts having a bolt hole diameter 1⁄16-inch (2 mm) larger than the bolt diameter. Use threaded bolts, transferring shear, that have no more than one thread within the grip of the metal. Furnish bolts that extend through the nuts a maximum ¼-inch (6 mm).
556.03.8 Bolted Connections - High-Tensile-Strength Bolts
A.General. Make bolted connections as recommended by the Steel Structures Technology Center’s Structural Bolting Handbook (Bolting Handbook).
1.Bolt Lengths. Use bolt lengths having the grip-length values in Table 556-1 plus the total thickness of connected material. The values in Table 556-1 consider nut, one flat washer, and bolt point. Adjust the length to the next ¼-inch (6 mm) increment up to a 5-inch (125 mm) bolt and to the next ½-inch (13 mm) increment for bolts over 5 inches (125 mm). Increase the bolt length ⅛-inch (3 mm) if direct tension indicator washers are used. 556 – STEEL STRUCTURES 2020 EDITION V5.1 556-6 TABLE 556-1 BOLT LENGTH DETERMINATION Bolt Diameter Added Grip Length1 English ½-inch ⅞-inch ⅝-inch 1-inch ¾-inch 1⅛-inch ⅞-inch 1⅜-inch 1-inch 1½-inch 1⅛-inch 1⅝-inch 1¼-inch 1¾-inch Metric M16 25 mm M20 30 mm M22 35 mm M24 40 mm Note: 1. Add to total thickness of connected material. Where beveled washers are used, adjust bolt lengths to account for the use of nonstandard or beveled washers.
2.Bolted Parts. Ensure bolted surfaces in contact with the bolt head and nut do not have a slope of more than 1V:20H to a plane normal to the bolt axis. Ensure bolted parts fit solidly when assembled. Provide a Class B finish, per AASHTO LRFD Bridge Construction Specifications for all faying surfaces.
3.Washers. Install fastener assemblies with hardened washer(s) in accordance with the Bolting Handbook.
B.Pre-Installation. Submit 1 of the following bolt methods for use:
a.Turn of the nut,
b.Calibrated wrench,
c.Direct Tension Indicator (DTI), or
d.Tension Control Bolts (twist-off) Pre-Installation verification is not required for structural support for highway signs, luminaires, and traffic signals. Not applicable to breakaway connections.
1.Pre-Installation Verification Testing. Perform Pre-installation verification procedures in accordance with the Bolting Handbook. Retest when directed by the Project Manager.
2.Reuse of bolts previously tightened. Reuse of bolts previously tightened is not permissible except as described in the Bolting Handbook.
C.Production Bolting. Tighten bolts in accordance to the pre-tensioning procedures given in the Bolting Handbook. Fully erect continuously supported girder sections between expansion joints before production bolt tightening. 2020 EDITION V5.1 STEEL STRUCTURES – 556 556-7 Tightening is dependent upon consistency of torque and is dependent on condition of the fastener assembly. Verify that the condition of assembly is equivalent to those used in the Pre-installation Verification test. Conditions of the assembly and the efficiency of the lubricant can be affected by the following:
1.Exposure to the elements during storage.
2.High temperatures during storage.
3.High temperatures during tightening.
4.Low temperatures during tightening.
5.Additional moisture from snow and rain during tightening.
6.Passing of time between the snugging operation and tightening. If these condition changes occur, repeat the pre-installation verification test on a representative sample of fastener assemblies to be tightened. Lubricate bolts in accordance to the Bolting Handbook. Re-lubricating of tension control bolts may only be performed by the manufacturer.
D.Metric Bolt Substitution. Allowable bolt substitutions are shown in Table 556-2. 556 – STEEL STRUCTURES 2020 EDITION V5.1 556-8 TABLE 556-2 BOLT SUBSTITUTIONS High Strength Bolt Substitution Specified Bolt Grade A325M or Grade A490M Allowable Substitute Grade A325 or Grade A490 M16 ⅝-inch M20 ⅞-inch M22 ⅞-inch M24 1-inch Standard Bolt Substitution Specified Bolt ASTM F568M Class 4.6 Allowable Substitute ASTM A307 M6 ¼-inch M8 5⁄16-inch M10 ⅜-inch M12 ½-inch M14 9⁄16-inch M16 ⅝-inch M20 ⅞-inch M22 ⅞-inch M24 1-inch Stud Bolt Substitution Specified Bolt ASTM F568M Class 8.8 Allowable Substitute ASTM A449 M12 ½-inch M14 9⁄16-inch M16 ⅝-inch M20 ⅞-inch M22 ⅞-inch M24 1-inch
556.03.9 Welded Stud Shear Connectors
The type, size or diameter, and length of stud shear connectors are specified in the contract. Furnish fabrication material and perform welding in accordance with Section 624.
A.Shop Drawing Review. Provide alternate stud locations that will avoid conflict with safety and lifting devices. Ensure that all shear studs are a minimum of 6 inches away from top flange shop splices. Obtain approval from the Bridge Bureau before installing any studs in these alternate locations. 2020 EDITION V5.1 STEEL STRUCTURES – 556 556-9
B.Field Removal. Stud shear connectors that are removed in the field must use one of the following removal methods:
1.Cut completely through the stud above the weld.
2.Partially cut the stud above the weld and break off the stud the rest of the way. Prevent damaging the base metal during stud removal.
C.Field Replacement. Replace all stud shear connectors that are removed in the field. Replacement shear studs must be within 3 inches (76 mm) of the original stud location, no closer than 1½ inches (38 mm) from base metal edges, and at least 1 inch (25 mm) between adjacent studs. Follow all the surface preparation, field welding, and testing requirements in accordance with AWS D1.5.
D.Additional Payment. No additional payment will be made for field removal and replacement of stud shear connectors and base metal inspection, repair, or replacement.
556.03.10 Field Welding
Do not weld temporary construction supports to beams, girders, or other main members. Any member with unauthorized field welds, tack welds, or arc strikes will be rejected. Perform welding in accordance with Section 624 .
556.03.11 Assembling Steel
Field or shop assemble steel parts as follows:
A.Shop Work. Clean all contacting metal surfaces of deleterious materials before assembling, bolting, or welding. Paint may be applied to contact surfaces after bolting or welding. Shop assemble and adjust to line and camber all bolted trusses, continuous plate girders, curved steel elements, box girders, I-beam spans, skew portals, skew connections, rigid frames, bents, and towers. Drill and ream the field splice holes during assembly. Holes for other field connections may be shop drilled or reamed with the connecting parts assembled or drilled or reamed to metal templates with hardened bushings, without assembling. Use an approved alternate procedure where shop space prevents complete shop assembly of continuous span girders or trusses. The procedure may require adjusting the line and camber of at least two abutting sections of girder for drilling or reaming of field splices if all girder lines for the complete structure are assembled consecutively. Field butt joints for welded girders may be assembled with abutting members adjusted for line and camber and prepared to fit for welding, subject to Project Manager approval. Bridge expansion devices must be initially shop assembled to establish the proper fit between the joint parts.
B.Field Work. Assemble the parts as specified in the contract, following the match-marks. Prevent damaging the material while handling. Clean all bearing and member surfaces in permanent contact before assembly. Splices and field connections must have a minimum of ½ of the holes filled with bolts or erection pins before removing temporary supports or releasing the load from erecting equipment. Splices and connections carrying traffic during erection must have ¾ of the holes pinned or bolted. Do not begin production bolt tightening of the field splice bolts until the complete girder line is aligned and erected matching the full camber line. Do not place deck forms 556 – STEEL STRUCTURES 2020 EDITION V5.1 556-10 or other loads on straight steel girders until all girder splice bolts are fully tensioned. For curved structures, fully tension all bolts before placing deck forms or other loads. Use erection pins 1⁄32-inch (1 mm) larger than the nominal diameter of the permanent bolts. Erect truss spans on blocking, unless they are erected using the cantilever method, to provide truss camber. Leave the blocking in place until the tension cord splices are fully bolted, and all other truss connections pinned and bolted. Do not tension bolts in butt joint splices of compression members and in railings until the span is swung.
C.Drifting of Holes. Only use drift pins during assembly to the extent necessary to bring the parts into position without enlarging or distorting the holes or metal. Do not ream holes during field fitting without approval from the Project Manager.
D.Match-marking. Match-mark parts assembled in the shop for reaming field connection holes and provide the Project Manager a diagram showing the marks.
556.03.12 Marking and Shipping
Paint or mark each member with an erection mark and furnish the Project Manager an erection diagram detailing the erection marks. Furnish copies of material orders, shipping statements, and erection diagrams. Show the individual member weights on the statements. A shipping statement must accompany the material and be marked to clearly identify it with the delivered material and the relevant domestic material and contract specification certifications. Mark the weight on members weighing 3 tons (2.7 MT) or more. Load and unload structural members on trucks or cars without stressing or causing damage. Pack bolts, loose nuts, or washers of each size separately. Ship pins, small parts, bolts, washers, and nuts in boxes, crates, kegs, or barrels, with the gross weight of each package not exceeding 300 pounds (136 kg). Plainly mark each shipping container, listing and describing the contents on the outside of each shipping container. Keep structural material clean and free from damage.
556.03.13 Painting
Clean and paint all iron and steel surfaces in accordance with Section 612 .
556.03.14 Erection
Submit a steel erection plan and specifications that ensures safety, prevents overstressing of the steel, maintains stability, prevents damage to the work or surroundings, and achieves the proper final geometry. Submit a complete erection plan and specifications for erection of the steel and for any falsework necessary, including temporary bracing, guywires, or other required items. The erection plan and specifications must bear the signature and the professional seal of a professional engineer licensed to practice in Montana.
556.03.15 Falsework
Design, construct, and maintain falsework to support the maximum construction loadings. Check and approve falsework drawings before submitting. The Department has 20 business days to review and return the falsework drawings. The contract time will be extended day for day for any delay beyond the 20-day review period if the Department’s delay affects the Contractor’s operation as shown on the current work schedule. 2020 EDITION V5.1 STEEL STRUCTURES – 556 556-11
556.03.16 Bearing and Anchorage
Place masonry bearing plates in accordance with Subsection 565.03.2.
556.03.17 Placing Anchor Bolts
Place anchor bolts in accordance with Subsection 552.03.13.
556.03.18 Straightening Bent Material
Straighten bent plates, angles, or other shapes without damaging the material. The metal may be heated if approved. Do not exceed 1,000 °F (537 °C). Once heated, cool the metal slowly. All straightened metal will be inspected for defects.
556.03.19 Pin Connections
Furnish the Project Manager the pilot and driving nuts provided with the steelwork once the work is complete. The members must take full bearing on the pins. Bring pin nuts up tight and burr the threads at the nut face.
556.03.20 Misfits
Correct all misfits, errors, and injuries as a part of the assembly and erection work. Report to the Project Manager all shop work errors that prevent the assembly and fitting of parts with a minimum use of drift pins, reaming, slight chipping or cutting. Obtain Department approval for the correction method. Corrections must be inspected and approved.
556.03.21 Cleanup
Remove all falsework, excavated or unused materials, rubbish, and temporary buildings. Restore all public and private property damaged during construction to its original condition. Pull, cut off or otherwise remove all falsework piling 1-foot (305 mm) below finished the ground line or streambed, unless otherwise directed. Perform all work affecting the stream channel in accordance with Subsection 208.03.4 before final acceptance.
556.03.22 Rejections
An Inspector’s acceptance of material or finished members does not prevent later rejection if defects are found. Replace or repair rejected material and work at Contractor expense.
556.04 Method of Measurement
Structural steel is measured by the lump sum.
556.05 Basis of Payment
Payment for the completed and accepted quantities is made under the following: Pay Item Pay Unit Structural Steel Lump Sum The weight of structural steel in the contract is an estimate only. No guarantee is made that the estimated weight is the correct weight to be furnished. No adjustment in the contract unit price is made if the weight furnished is more or less than the estimated weight. If changes in the work ordered by the Project Manager vary the weight of steel to be furnished, the lump sum payment is adjusted as follows: The value per pound (kg) of a decrease or increase in the weight of structural steel involved is determined by the following: Value per Pound (kilogram) = Contract Lump Sum Bid Estimated Contract Weight 556 – STEEL STRUCTURES 2020 EDITION V5.1 556-12 The adjusted contract lump sum amount paid is the contract lump sum bid plus or minus the value of steel involved in the change. Should the ordered change materially alter the character of the work and the unit cost, compensation for that work is made at an agreed price established before the work is performed. Detail in writing, the changes in procedures and the resulting costs for labor, equipment, and materials to support the agreed price. Partial payments for structural steel will be made based on the lump sum contract unit price as follows:
1.90% when erected.
2.97% when bolted and spot painted.
3.100% when painted in compliance with the plans and specifications.
Referenced in this section
Steel Structures in other states
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Source: Standard Specifications for Road and Bridge Construction, 2020 (v5.1) Edition. Pages 355–366 of 611. View official source ↗