705 - STRUCTURAL STEEL FABRICATION - BRIDGES
700-24 Store structural steel, either plain or fabricated, ab ove the ground on platforms, skids or other supports, and
keep free from corrosion, dirt, grease and other foreign matter. Store girders and beams upright with sufficient support to prevent warping or change in design camber.
d.Shop Fabrication.
1.Steel Identification. All pieces of all grades of steel used in fabr ication of main members, including webs, flanges, bearing stiffeners, bearing devices, splice plates and any cross member carrying stringers and their connection plates, must bear the heat number assigned by the rolling mill. Preserve the heat number until the Engineer advises the fabricator that th e unit is acceptable for cleaning and pain ting. Identify the grade as specified in ASTM A 6. (2) Straightening Material. All mill material must be straight before being laid out for work. If straightening is required, do not injure the metal. Heat straightening must comply with the latest versions of AASHTO/AWS D1.5, "Bridge Welding Code"; AASHTO’s "Standard Specifications for Highway Bridges"; AASHTO’s "LRFD Bridge Construction Specifications"; and the FHWA report, "Heat-Straightening Repairs of Damaged Steel Bridges". Submit the proposed heat straightening procedure to the Engineer for approval. Sharp kinks and bends are cause for rejection of the material. Mill material must not exceed dimensional tolerances outlined in the latest edition of ASTM A 6.
3.Welding and Gas Cutting. Perform welding an d gas cutting of structural steel according to the applicable requirements of the AA SHTO/AWS D1.5-2010, "Bridge Weld ing Code" with the exceptions and additions noted in this specification. Perform welding and gas cutting on steel bearings, bridge drainage sy stems, finger plate or modular expansion devices, and bridge rails according to SECTION 744 . At the option of the E ngineer, steel bearing device inspection will require that either 1 device in 10, or fraction thereof, be tested 100%, or a10% of each device will be tested using liquid penetrant or magnetic particle. When te sted at the 1 in 10 rate, the Engineer will select which device to test. When tested at the 10% rate, the Engineer will select the weld locations to test, which can vary from device to device. The welding of dissimilar metals is not prequalified.
4.Finish. Neatly finish all work. Carefully and accurately shear and clip. Fabricate finished members true to line and detailed dimension, and free from twists, bends, open joints or other defects.
5.Pins and Rollers. Accurately turn pins and rollers to the dimensions shown in the Contract Documents and keep them straight, smooth and free from flaw s. Produce the final surface by a finishing cut. Forge and anneal pins and rollers larger than 7 inches in diameter, unless shown otherwise in the Contract Documents. In addition, for pins larger than 9 inches in diameter, after the forging has been allowed to cool to a temperature below the critical range, under normal conditions, and before being annealed, bore a hole a minimum of 2 inches in diameter full length along the axis. (6) Boring Pin Holes. Bore pin holes true to the specified diameter, smooth and straight, at right angles with the axis of the member and paralle l with each other, unless otherwise specified. Produce the final surface by a finishing cut. Do not vary the distance outside-to-outside of holes in tension members and inside-to-inside of holes in compression members from the specified dimension more than 1/32 inch. Bore holes in built-up members after final assembly. (7) Pin Clearances. Do not exceed the diameter of the pi n hole by that of the pin more than 1/50 inch for pins 5 inches or less in diameter, or 1/32 inch for pins greater than 5 inches in diameter.
8.Threads. Closely match threads of bolts to the nut threads. Threads must be ANSI Unified Coarse Series (UNC), except make pin ends of diameters gr eater than 1 ½ inches, with 6 threads per inch.
9.Pilot and Driving Nuts. Provide 2 pilot nuts an d 2 driving nuts for each size of pin, unless otherwise specified. (10) Fit of Stiffeners. Mill, grind or machine cut be aring stiffeners intended as supports for concentrated loads to secure full bearing against the flange. Use interm ediate stiffeners with a tight fit and uniform distance between the flange plates and the ends of the stiffeners, unless shown otherwise in the Contract Documents. (11) Facing of Bearing Surfaces. Plane or heat straighten the top and bottom surfaces of steel slabs, base plates, bearing devices, cap plates of columns and pedestals to have full contact when assembled to the main members. Mill parts of members in co ntact with these items to true surfaces and correct bevels, after the main sections of these members and the end connection angles have been fully welded or bolted. Plane cast pedestals on surfaces in contact with steel. 705 - STRUCTURAL STEEL FABRICATION - BRIDGES
700-25 Unless shown otherwise in the Contract Documents, adhere to the following surface roughness
requirements as defined in ANSI B46.1, Surface Texture, Roughness, Waviness, and La y, Part 1 for the surface finish of bearing and base plat es and other bearing surfaces that are to co me in contact with each other or concrete. Surfaces will be evaluated by visual or actual co mparison with roughness comparison specimens. Sliding Bearings ANSI 125 Microinches Bridge Rollers and Rockers ANSI 250 Microinches Pins and Pin Holes ANSI 125 Microinches Steel Slabs ANSI 2000 Microinches Heavy Plates in Contact with Shoes to be Welded ANSI 1000 Microinches Milled Ends of Compression Members, Milled ANSI 500 Microinches or Ground Ends of stiffeners and Fillers
12.Welded Stud Shear Connectors. Apply welded stud shear connectors to th e designated structural members during shop fabrication. If the circumstances warrant, and if the Engineer appr oves the Contractor’s procedures, welded stud shear connectors may be field applied. Approval is based on demonstrating to the Engineer’s satisfaction, that the Contractor can: remove any shop applied coating removed from the top flange without damaging the structural member; weld the stud shear connectors to the structural member; and blast clean and prime coat the top flange and stud shear connectors.
13.Holes for Bolted Connections. When field bolts are required, adjust the girders or beams so the maximum final clearance between abutting ends of the web plat es or flange plates is ¼ inch. Attach the web splice plates using sub-drilled holes in each corn er of the splice plate. Secure them with bolts and drill the remaining holes full diameter from the solid. Add additional bolts and full si ze pins as the holes are drilled to secure the splice plates to the web. Clamp the flange splice plates and bars into position, and drill the bolt holes full diameter from the solid. Add additional bolts as the holes are drilled to secure the splice plates to the flanges. Other methods of preparing flange and web field splices may be utilized w ith written approval of the Engineer. Fill plate thicknesses shown in the Contract Documents are based on nominal ASTM A 6 shape dimensions. Revise plan fill plate thicknesses as necessary to account for as -rolled variations in flange and we b thickness or overall beam depth. Minimum fill plate thickness is ⅛ inch or as required so that surfaces to be in contact shall be offset a maximum of 1/16 inch. Either punch or drill all holes for bolts except in flange s and webs of beams, girder s or stringers. Material forming parts of a member composed of a maximum of 5 thicknesses of metal may be punched 1/16 inch larger than the nominal diameter of the bolts whenever the total thickness of the material is a maximum of ¾ inch for structural steel, ⅝ inch for high-strength steel or ½ inch for quenched and temp ered alloy steel. If there are more than 5 thicknesses, or if the mate rial is thicker than ¾ in ch for structural steel, ⅝ inch for high-strength steel, or ½ inch for quenched and tempered alloy steel, either sub-drill and ream or drill all holes full size. The diameter of the die for punched holes may not excee d the diameter of the punch more than 1/16 inch. If any holes must be enlarged to admit the bolts, ream such holes. Clean cut holes leaving no torn or ragged edges. Poor matching of holes will be cause for rejection.
14.Shop Assembly for Final Inspection. Unle ss otherwise provided both in writing and shown on the approved shop drawings, assemble, securely support, adjust and maintain to proper line, grade, camber and suitable clearances all welded plate girders, rolle d wide flange beams, trapezoidal plate “tub” sections and other sections of main members. After the assembly is completely set up, the fabricat or’s quality control personnel must check blocking, sweep and bearing-to-bearing measurements prior to any checking by the Engineer. Reference “affect” measurements to the bottom of the we b or the top face of the bottom flange at or near the centerline of the web. Alternate re ference points may be accepted by the En gineer for Type “A” or “C” (vertical web) assemblies. Drill all splice holes and adequately bolt or pin splice pl ates in place before the assembly is checked by the Engineer. Use a minimum of 6 full size dr ift pins, full size bolts or a combina tion of both full size pins bolts at each flange and web splice for girders and rolled beams. For the purposes of checking the assembly, full size means the diameter equal to the diameter of the hole. 705 - STRUCTURAL STEEL FABRICATION - BRIDGES
700-26 In making the final assembly, if re-cutting is necessa ry to form a uniform widt h opening across the joint,
finish the butt joint by precision flame cutting or flame cutting and grinding to produce the same smoothness as the precision cut. Mechanical chipping is prohibited. Fit, drill or ream and bolt into place erection angles, while the beams or gi rders are in the fit-up position so that standard drift pins can be driven through any combination of holes, and the beams or girders can be pulled to correct spacing for field welding when erected at the bridge location. The types of assemblies are as follows: Type "A" Assembly (For structures with horizontal curvature transitions, super elevation or ramp tie-ins) requires a minimum of 2 spans (bearing to be aring) laid-out full bridge width, with separators attached at pier points (a minimum) or as direct ed by the Engineer. When released, carry the pier pieces back for the next additions. Include the gird er or beam expansion devices in position in the assembly, if attached directly to the structural steel. Requests for a lesser width of the assembly for lack of shop space must be approved in writing by the Bureau of Construction and Materials. If the request is approved, the Contractor may be back charged for excessive shop inspection trips and expenses. Type "B" Assembly requires a minimum of 2 lines and 2 spans (bearing to bearing) in each line laid-out to correct line with webs vertical or horizontal. When released, carry 1 pier piece per line back for the next additions. Type "C" Assembly (for long span, deep girders) requires a minimum of 2 spans (bearing to bearing) laid-out to correct alignment with webs horizontal or vertical. The spans may all be from different lines. When released, carry 1 pier pi ece per line back for the next additions. All assemblies are Type "B" unless stated otherwise in the Contract Documents. All desired changes to the requirements of the type of assembly for a particular structure must be approved in writing before submitting the shop drawings for approval. Submit requests for assembly changes to the Bureau of Construction and Materials. Without written approval from the Bureau of Construction and Materials, the fabricator must set up assemblies according to the original requirements in the Contract Documents, even if appr oved shop drawings show changes to the type of assembly. Take down the assembly only after being inspected and accepted by the Engineer. No welding on girders or beams will be permitted after the final assembly has been inspected and accepted by the Engineer. Use numbered tapes calibrated by the National Institute of Standards and Technology (NIST) or tapes calibrated from a certified master tape in order to check assemblies for bridges with spans over 100 feet. Provide a copy of the certification papers, calibra tion charts, and tape identification numbe rs before the first assembly is set up. In addition, submit to the Engineer for approval, procedures for calibrating tapes and the shop’s practices when using calibrated tapes. This approval is required prior to initial assembly se t-up. Calibrate measuring tapes for a minimum tension of 5 pounds. Prior to calibrating or meas uring, allow time for the tapes to reach uniform ambient temperatures so that temperature corr ections are not required. Replace or repair, and re-certify or re-calibrate damaged tapes. Re-certify master and re-calibrate NIST tapes every 5 years, or as directed by the Engineer. (15) Matchmarking. Matchmark all butt joints (girders, expansion devices, end separators under expansion devices or other specialties to be field assembled and welded or bolted into the final unit) while shop assembled, in the manner indicated as "Typical Matchmark", and shown on the approved shop drawings. Use a coordinate system of capital letter and numbers as follows: Mark each line of girders with a capital letter. Looking upstream, mark the outside line, left of centerline, with the first letter of a series. Mark the girders in the next line to the right with a second letter of the series, etc., until all lines have been marked; and Mark the field splices (points of contraflexure) with numbers. Pl ace the lowest number on the splices nearest abutment number 1 and the highest number on the splices nearest abutment number 2. Number the splices consecutively from abutment number 1 to abutment number 2. Place these on each of the girder ends that comprise the splice and within 3 feet of the field spli ces in the center of the web. Use low stress steel die marks placed be fore shop blasting and painting. Orient letters and numbers so they are upright when the top flange is up. Matchmark essential special fit-ups discovered in shop production. Provide a corrected set of shop details and erection drawings showin g these special fit-ups. Do not matchmark the exposed surface of "Weathering " Steels with paint, crayon or any other type of material which will impair the weathering process of the steel. 705 - STRUCTURAL STEEL FABRICATION - BRIDGES
700-27 (16) Shop Painting. Prepare the structural steel surfaces and shop pa int the prepared surfaces according to
SECTION 714 .
17.Shop Bolted Connections. Perform all bolting according to SECTION 712 . The maximum deviation from detailed flatness for a connected plate (flange, web, splice, fille r, etc.) shall no t exceed D/(144*T0.5) inches or 3/16 inch, whichever is greater. D equals the least clear dimension (in inches) of the panel from edge to edge, flange to flange, web to web, stiffener to stiffener, or any comb ination thereof and T equals the thickness (in inches) of the connected plate. After snug tightening all fasteners, no gaps between the conn ected layers can be present except at the edges of splice plates away from bolt holes.
18.Enclosed structures not accessibl e after fabrication. All interior welds and connections as well as overall fit and finish must be inspected and accepted prior to full enclosure. Failure to provide the Engineer this opportunity will be cause for rejec tion of the fabricated element.
19.Rejection. Repair or replace reject ed items as directed by the Engineer.
20.Release for Shipment. Do not release fabricated elements for shipment fro m the fabrication shop or paint shop without approval of the Engineer.
e.Supplemental Requirements to the Welding Code. The section and paragraph references cited in the paragraphs below are to AASHTO/AWS D1.5-2010. SUBSECTION 1.3 WELDING PROCESSES Delete paragraph 1.3.2 and add the following: 1.3.2 Electrogas welding shall not be used. Replace the third sentence of paragraph 1.3.3 with the following: Only the “narrow-gap improved” ESW process (ESW-NG) shall be permitted. Add 2 new subsections as follows: SUBSECTION 1.12 EQUIPMENT CHECK Each DC generator shall have a service check by an NEWA member, a commercial electrical equipment company or by the fabricating plant's electrical maintenanc e engineer once each year. A service certificate shall be issued with each equipment check and shall be available for inspection by the Engineer. SUBSECTION 1.13 TEMPORARY WELDING AND TACKING The attachment of temporary fabrication, erection and construction items to main members by welding or tacking is prohibited except by written permission from the Bureau Chief of Construction and Materials. Permissible locations for such welds and tacks sh all be only at locations shown on approved shop drawings or at locations designated in writing by the Engineer. A ll such tacks or temporary welds shall be made according to Paragraphs 3.3.6 and 3.3.7 and welders and/or tackers shall be qualified according to AWS requirements. SUBSECTION 2.9 DETAILS OF PLUG AND SLOT WELDS Add the following to paragraph 2.9.1.1: Plug welding is prohibited without the written approval of the Engineer. As a requirement for approval, all plug welding shall be QC tested by nondestructive testing at no cost to the state. The type of testing shall be determined by the Engineer. SUBSECTION 3.4 CONTROL OF DISTORTION AND SHRINKAGE Add the following to paragraph 3.4.8: Do not use mechanical straightening methods w ithout the approval of th e Engineer, even when used in conjunction with the application of heat. SUBSECTION 3.5 DIMENSIONAL TOLERANCES Add the following to paragraph 3.5.1.2: Permissible variations in straightness of rolled beams, regardless of cross- section, shall not exceed 0.01inch/foot of beam length or 1 inch. Delete paragraph 3.5.1.3 and add the following: 3.5.1.3 Permissible variations in specified cambe r and blocking of welded girders and rolled beams, regardless of cross-section shall not exceed: -0, +¼ inch for spans (typ., bearing to bearing) 0 thru 100 feet -0, +½ inch for spans greater than 100 feet Permissible variations in blocking of rolled beams at field splices, regardless of cross-section, shall not exceed:
Source: Kansas Standard Specifications for State Road and Bridge Construction, 2015 Edition. Pages 355–358 of 978.