for Highway Construction Page 334 of 71 5 SECTION 504 – STRUCTURAL METALS
504.01 Description.
A.General. Provide, fabricate, erect, and paint structural met als.
B.Fabricator Certification . Fabricators of structural components for vehicular bridges, other than unspliced rolled beam bridges, are to be certified under the AISC Quality Certification Program, intermediate or advanced steel bridge categories. Fabricators of structural components for unspliced, rolled beam vehicular bridges and steel pedestrian bridges are to be certified under the AISC Quality Certification Program, simple steel bridge structures category. Fabricators of fracture critical members are to hold a fracture critical endorsement in addition to the above requirements. This does not apply to incidental sub-assemblies (e.g., drainage components, expansion joints , handrails, lighting supports ).
C.Notice of Rolling and Fabrication. Give a 90 -day notice before beginning work at the mill or shop so the Department can prepare for inspection. Do not manufacture material or perform work in the shop before the Engineer has been notified.
D.Inspection. The Department will inspect structural steel at the fabrication site. Submit electronic copies of mill orders, certified mill test reports and shipping statements. On mill test reports, show the chemical analysis and physical test results for each heat of steel used in the work. Submit certificates of compliance instead of mill test reports for material that normally is not supplied with mill test reports (e.g., fills, minor gusset plates, quantities are small and the material is taken from s tock). Submit certified mill test reports for steels with specified impact values that include, in addition to other test results, the results of Charpy V -notch impact tests. When fine grain practice is specified, include confirmation the material was so produced. Submit copies of mill orders at the time orders are placed with the manufacturer. Submit certified mill test reports and certificates of compliance before starting material fabrication covered by these reports. Submit the certificate of compliance signed by the manufacturer certifying the material is in compliance with the specifications to which it has been manufactured. Make available to the Engineer material to be used so each piec e can be examined. Provide the Engineer with safe access to the fabrication site where the material is stored or where work on the material is being performed.
E.Quality Control Inspection . Be responsible for quality control inspection and testing. Perform inspection and testing at least to the extent specified and in accordance with the ANSI/ AASHTO/ AWS D1.5 Bridge Welding Code, Inspection. Include nondestructive testing in addition to visual inspection, testing to base metal, production welds, weld repairs , procedure qualification test weldments and welder, wel ding operator, and tacker qualification test weldm ents. This work is incidental and the costs are to be included in the contract unit prices for the structural steel . Provide facilities to inspect material and work. for Highway Construction Page 335 of 71 5 F. Shop Plans . Submit working drawings for fabricating the steel. Include on each drawing and calculation sheet the project name as specified , district -county -route, bridge number, contract number, contract drawing number, and key number. Submit welding procedures for approval with shop drawings. Include the type of equipment and electrode to be used, preheat requirements, base materials, and joint details. When the procedures are not prequalified by AWS or AASHTO , submit evidence of qualification tests. The Department accepts only the nature and scope of the details without validating dimensions in approving working drawings. Do not make changes in drawings after approval. Submit as -built shop drawings .
G.Erection Plans . Submit the proposed erection plan for approval. The Department requires the erection procedure be r eviewed by the steel fabricator before being submitted. Include in the submittal, maximum stress calculations that each member will be subjected to during erection. Use these calculations to determine the necessity of using strongbacks or erecting the girders in pairs with cross frames installed to prevent the possibility of buckling the compression flange during girder erection. Sign and seal the calculations and plans by an Idaho licensed professional engineer. Ensure falsework or temporar y structures meet the requirements of 502.03.E. Supplement the erection procedure with necessary drawings to clearly describe the method proposed. Include details of falsework bents, bracing, guys, temporary anchors, lifting devices, attachments to the bridge members, sequence of erection, location of lifting points on the bridge members, and weights of the members. Submit the plan and drawings in detail for anticipated phases and conditions during erection. Submit plans of temporary members or devices that affect stresses in the permanent members of the structure. Remove temporary or extra material. The Department will not pay for extra material required due to the Contractor’s erection procedures or method or for material required in the permanent structure due to the Contractor’s erection scheme. Be responsible for the practicality and safety of the erection schemes used and carrying out the work as specified. Be responsible for material ordered or shop drawings prepared before the Engineer reviews the erection scheme. Submit the plan and drawings for approval as specified in 502.03.E.4.
H.Camber Diagram. Submit a camber diagram from the fabricator, showing the camber at each panel point of trusses or arch ribs and at the location of field splices and tenth points of span length of continuous beam and girder or rigid frames. Show calculated cambers to be used in preassembly of field connections on the camber diagram. for Highway Construction Page 336 of 71 5 504.02 Materials.
A.Structural Metal s. Meet the requirements shown and as specified in 708.06. Meet the additional fabrication, inspection, and certificate requirements of the current AA SHTO Guide Specifications for Fracture Critical Non- Redundant Steel Bridge Members and current interim specifications for members identified as “fracture critical member(s).” Do n ot use universal mill plates for flange plates in designated tension stress o r stress reversal areas. Use structural steel classified as:
1.Structural carbon steel (use wherever the plans do not specify another classification ). Meet AASHTO M 270 Grade 36.
2.Structural low al loy steel. Meet AASHTO M 270 Grade 50 and 50W.
3.Structural high- strength steel. Meet AASHTO M 270 Grade 70W. The Department classifies the following as structural carbon steel:
1.Shims, ladders, stairways, anchor bolts and sleeves, pipe fittings and fastening used in handrails, and other metal parts, even if made of other materials, for which payment is not specified.
B.Painting. When required, paint the structural steel as specified in 627. Provide paint as specified in 707.
C.Handling, Storing, and Shipping of Materials. Apply markings at the mill to distinguish structural low alloy steel from structural carbon steel. Keep the 2 classes of steel separated. Protect material from rust, dirt, oil, and other foreign matter. The Engineer will not accept rust -pitted material. Ensure structural steel arrives in good condition. The Engineer may require thorough cleaning by high pressure water, flushing steel damaged by saltwater shipment, chemical cleaning or sandblasting, and repainting with the specified shop coat. Prevent rust and loss of small parts when storing material. Do not rest piled material on the ground or in water. Use skids or platforms. Conduct the loading, transporting, unloading, and piling of the structural steel material so the metal is kep t clean and not injured from rough handling. Keep girders and beams upright after fabrication during shipment, handling, and storage, unless otherwise approved in writing. Support long members (e.g., columns, chords) on skids placed near enough together to prevent damage from deflection. Use methods and equipment not likely to twist, bend, deform, or otherwise injure the metal in field assembly of structural parts. Correct any member slightly bent or twisted before it is placed. The Engineer may reject members that are damaged. Repair scratches and gouge marks caused by handling and lifting and located in tension or stress reversal regions, by grinding to a surface finish of ANSI 125 or better, and inspect by the dye penet rant or magnetic for Highway Construction Page 337 of 715 particle method. If the marks are located in an area where they will be covered or partly covered by a structural weld, grind and test before welding. Handle girder sections to prevent damage. Laterally support girders during shipment by blocking, removable flange bracing, bolting in pairs, or other approved method. Show the method of lateral support for the girders on the shop drawings . Mark the weight on members weighing more than 6,000 pounds and remove after erecti on is completed.
D.Castings. The specifications for structural steel , including painting requirements, also apply to castings. Provide castings that are:
1.True to pattern in form and dimensions.
2.Without pouring faults, sponginess, cracks, blow holes, and other defects in places that would affect strength, ap pearance, or value.
3.Clean and uniform in appearance.
4.Filleted boldly at angles.
5.Formed with sharp and perfect arises. Anneal iron, steel castings , and forgings before matching.
504.03 Construction Requirements.
A.Identification of S teels During Fabrication. Submit for approval a written plan for visibly marking the material so it can be traced. Ensure these m arks remain visible at least through the fit -up of the main load- carrying tension members. Provide a marki ng method that allows the Engineer to verify:
1.Material specification designation.
2.Heat number.
3.Material test reports to meet special requirements. Include the heat numbers on the reproducible copies of the as -built shop plans for steel i n main load- carrying tension members and in tension components of flexural members.
B.Edge Finishing. Finish rolled, sheared, and flame- cut edges tr ue to line and without rough corners and projections. Round corners along exposed edges to a radius of 1/16 inch or greater. Plane, mill, grind, or thermal cut to a depth of 1/4 inch sheared edges on material more than 5/8 inch thick. Do not exceed 250 mic ro-inches as defined by ANSI specifications for surface roughness of flange plates in designated tension stress or stress reversal areas (rolled, sheared, and flame- cut edges). The Contractor may obtain this roughness on flame- cut edges after cutting by grinding or other approved methods. Do not exceed 1,000 micro- inches surface roughness of other rolled, sheared, and flame- cut edges. for Highway Construction Page 338 of 71 5 C. Thermal Cutting. Take steps to ensure the flame- cut edges of main material are not hardened by the cutting process. The Contractor may achieve this by preheating, post heating, or control of the burning process. Edge hardness for AASHTO M 270 Grade 50 and 50W plates after flame cutting found to have a Rockwell hardness value of C30 or greater will be considered unacceptable. Determine hardness in accordance with AASHTO T 80. Test plate edges at least once for each fabrication piece. Remove unacceptably hard surfaces by grinding, machining, or heat treating procedures as approved. Preheat to the following temperatures when flame cutting AASHTO M 270 Grade 50/50W and above, or ot her high- strength low alloy steels as shown in Table 504.03 -1. Table 504.03 -1 – Preheat Temperature Thickness (t) of Thickest Part at Point of Cutting, in Temperature , °F t ≤ 0.75 50 0.75 < t ≤ 1.5 70 1.5 < t ≤ 2.5 150 t > 2.5 225 Preheat the plate so the required temperature is obtained through the full thickness of the plate ahead of and laterally from the cut a distance of 3 inches, or the plate thickness, whichever is greater. Show preheat temperatures on the shop drawings .
D.Fit and Bearing. Mill ends of columns that bear on base and cap plates to true surfaces and accurate bevels. When assembled, ensure caps and base plates of columns and the sole plates of girders and trusses have full contact. Heat straighten, plane, or correct the plates in some other way to produce accurate, even contact if plates are warped or deformed. If necessary, for proper contact, plane or mill bearing surfaces that will contact other metal surfaces. Rough finish surfaces of warped or deformed base and sole plates that will contact masonry. On the surface of expansion bearings, ensure the cut of the planer is in the direction of expansion. Face abutting ends of compression members accurately so they bear evenly in the structure. On built -up members, face or mill the end after fabrication. Rough finish ends of tension members at splices to produce neat, close joints . The Department does not require a contact fit. Ensure floor beams, stringers, and girders having end connection angles are flush with each other and set accurately in relationship to the position and length of the member. Unless the plans require it, do not finish end connection angles. If faulty assembly requires them to be milled, do not reduce milling thickness by more than 1/16 inch. for Highway Construction Page 339 of 71 5 Ensure the various pieces forming 1 built member are straight and close- fitting, true to detailed di mensions, and without twists, bends, open joints, or other defects. Do not exceed 3/8 inch clearance between web plates for field- bolted splices. Mill bearing stiffeners so they will bear evenly against the flange. Fit intermediate stiffeners tightly enough to exclude water after painting .
E.Grinding. Grind plates so the direction of grinding is parallel with the direction of tensile or compressive stress. Show the direction of grinding on the shop plans .
F.Camber . Do not camber in the plane parallel to the strong axis of the girder by the use of heat or mechanical bending. For plate girders, cut the web to the prescribed camber with suitable allowance for s hrinkage due to cutting, welding, and heat curving.
G.Curvature. Produce girder curvature in an axis parallel to the girder web as specified by fabrication methods that meet AASHTO Specifications for Highway Bridges Division II -Construction.
H.Pins and Rollers. Make pins and rollers of the class of forged steel specified. Turn accurately to detailed dimensions, smooth, straight, and flawless. Produce the final surface by a finishing cut. Forge and anneal pins and rollers more than 9 inches in diameter. The Contractor may cold- finish or forge and anneal carbon steel shafting pins and rollers 9 inches or less in diameter. In pins larger than 9 inches in diameter, bore a hole at least 2 inches in diameter full length al ong the axis after the forging has been allowed to cool to a temperature below the critical r ange and before being annealed. Cool under conditions that will prevent damage by cooling too rapidly. Bore pin holes true to detailed dimensions, smooth and straight, and at right angles to the axis of the member. Ensure holes are parallel with each other . Always make a finishing cut. Do not vary from detailed dimensions the distance between holes by more than 1/32 inch. Measure the distance in tension members from outside to outside of holes and in compression members inside to inside. Ensure each pin is 1/50 inch smaller in diameter than its hole. Number pins after being fitted into their holes in the assembled member. Magnetic particle test pins in accordance with ASTM A275 using an independent testing laboratory. The Engineer will reject pins with inner defects. Provide 2 pilot and 2 driving nuts for each size of pin.
I.Machine Finished Surfaces. As soon as possible and before they leave the shop, cover machine- finished surfaces on abutting chord splices, column splices, and column bases with grease. After erection, clean and paint the steel as specified. Paint surfaces of iron and steel castings milled to smooth with the primer called for in the specified paint syste m. for Highway Construction Page 340 of 715 While still in the shop, ensure machine- finished surfaces and inaccessible surfaces of rocker or pin- type bearings receive the full paint syste m. Do not paint surfaces of pins and holes machine- finished to specific tolerances. Coat with grease as soon as possible.
J.High -Strength Bolt Holes.
1.General. The Contractor may punch or sub- punch and ream, drill or sub- drill and ream, or form by numerically controlled drilling operations, holes subject to the condition described in t his section. Ensure the hole for each high- strength bolt is 1/16 inch larger than the nominal diameter of the bolt and less than 1 inch in diameter and 1/8 inc h larger for bolts with diameters greater than 1 inch. The fabricator may drill holes full size from the solid with every thickness of material assembled in proper position in forming any connection. If the fabricator chooses not to use this method, then the following methods apply:
a.Sub-punch or sub- drill holes, then ream full size after assembly in connections and splices in the main members of trusses, arches , continuous beam spans, bents, towers, plate girders, box girders, and rigid frames.
b.Drill holes full size unassembled to a steel template for splices of roll ed beam stringers that continue over floor beams or cross frames.
c.Sub-punch and ream holes full size to a steel template or reamed full size while assembled for end connections of rolled beam stringers and floor beams or cross frames. If steel templates ar e used to ream or drill full -size connection holes, position and angle the templates with extreme care and bolt firmly in place. Use duplicate templates for reaming matching members or the opposite faces of one member. Locate templates for connections on l ike parts or members with such accuracy that match- marks are not needed. The Contractor may punch or drill bolt holes full size in cross frames, gussets, later al braces, and other secondary members from the solid while assembled.
2.Punched Holes. For punched holes, ensure the die diameter does not exceed punch diameter by more than 1/16 inch. Ream holes requiring enlargement to fit the bolt. Cut holes clean with no torn or ragged edges. The Engineer will reject components having poorly matched holes. Ensure after shop assembly and before reaming, pu nched, sub- punched, and sub- drilled holes meet the following standard of accuracy:
a.At least 75 percent of the holes in each connection allow the passage of a cylindrical pin 1/8 inch smaller in diameter than nominal hole size.
b.The pin passes through at right angles to the face of the member without drifting.
c.Holes allow passage of a pin 3/16 inch smaller in diameter than nominal hole size. The Engineer will reject pieces that fail to meet these standards.
3.Reamed and Drilled Holes. Use drills for reaming and drilling, producing cylindrical holes perpendicular to the member. Reamers and drills are to be directed mechanically , not hand- held. for Highway Construction Page 341 of 715 Assemble connecting parts that require reamed or drilled holes and hold securel y as the holes are formed, then match- marked before disassembly. Submit a diagram showing these match- marks. The Engineer will reject components having poorly matched holes. Remove burrs on outside surfaces and mating surfaces. Disassemble parts to remove burrs. Ensure at least 85 percent of holes in a connection of reamed or drilled holes show offsets of 1/32 inch or less between adjacent thicknesses of metal, with no hole having an offset greater than 1/16 inch. Inscribe centerlines from the connection on the template and locate holes from these centerlines. Use centerlines for accurately locating the template relative to the milled or scribed ends of the membe rs. Insert templates with hardened steel bushings into each hole. The fabricator may omit these bushings if the template will be used less than 5 times and use will not produce template wear. Ensure each template is at least ½ inch thick. If necessary, use thicker templates to prevent buckling and misalignment as holes are formed.
4.Numerically Controlled (NC) Drilled Connections. The fabricat or may use NC drilling or punching equipment in forming holes described in this section if it meets the following requirements: Submit for approval a detailed outline of proposed NC procedures, including:
a.Steps from initial drilling or punching through check assembly.
b.The specific members of the structure to be drilled or punched, hole sizes, locations of the common index, and other reference points, make- up of check assemblies , and other informati on needed to describe the process fully. The fabricator may drill or punch to size through individual pieces or through a combination of tightly clamped pieces. Show the NC procedures consistently produce holes and connections meeting these specifications when required.
5.Fitting for Bolting. Well pin and draw firmly together parts of a m ember before drilling, reaming, and bolting begins. If necessary, take assembled pieces apart to allow removal of burrs or shavings produced as the holes are formed. Ensure the member is without twists, bends, and other deformation. Blast clean contacting metal surfaces in shop- bolted connections before assembly. Blast in accordance with the Society for Protective Coatings (SSPC) SSPC -SP-6. Ensure drifting done during assembly does no more than enough to bring the parts into place and that drifting does not enlarge the holes or distort the metal.
K.Assembly.
1.Progressive Truss or Girder Assembly. Use progressive truss or girder assembly methods described as f ollows:
a.Obtain approval of the shop assembly and the erection methods before work begins. for Highway Construction Page 342 of 715 b. Assemble each truss or girder in stages over the full length of the superstructure.
c.For trusses, include at least 3 contiguous panels in the first stage.
d.For girders, include at least 3 contiguous shop sections in the first stage. After stage one h as been completed, assemble each next stage to include at least 1 panel or shop section of the previous stage, repositioned if necessary, and pinned to ensure accurate alignm ent, and add 2 or more panels or shop sections at the advancing end. If the bridge is longer than 150 feet, ensure each stage is at least 150 feet long, regardless of the length of individual continuous panels or shop sections. Perform the assembly sequenc e in the same order the structure will be assembled in the field.
2.Check of Shop As sembly. Check each assembly for alignment, accuracy of holes, fit of milled joints , and other assembly techniques. Do not begin drilling or reaming until approved. If the Contractor uses NC drilling, obtain approval before the assembly or st age is dismantled.
3.Blasting Cleaning. For painted structures after fabrication, blast clean structural steel , except machine- finished surfaces, to a “near white” finish in acc ordance with SSPC -SP10. The “near white” surface is shown in the pictorial standards of SSPC -Vis 1 -67T as A Sa 2.5 and C Sc 22.5. After blasting and before painting, remove loose dust and dirt that remains on the steel. Do not use acid to remove scale or stains. For unpainted weathering steel structures , after fabrication, blast clean steel surfaces in the shop, except th ose to be embedded in concrete, in accordance with SSPC -SP-6. Pro vide a blasted appearance that is equal to or better than BSa2 as shown in the pictorial standards of SSPC -VIS 1 - 89. Blast clean after erection as specified in 504.03.N.4.b. Blast clean faying surfaces as specified in 504.03.L and 504.03.J.5. Comply with 503.03.N.4.
L.Bolted Connections.
1.General. High- strength bolted connections are slip critical. Type 1 or Type 2 bolts are required for painted structures and Type 3 bolts for unpainted structures. Type 3 weathering steel is required for Direct Tension Indicators (DTIs). Provide bolts , nuts, hardened washers, and DTIs as specified in 708.06. Clean metal surfac es before fitting and bolting of the connection. Ensure assembled joint surfaces, including surfaces adjacent to the bolt head and nut, are free of dirt, road oil, and other foreign material. When splices are designated class B, slip -critical, f ield inspect the contact surfaces of splices immediately before assembly to ensure the surfaces are free of mill scale, dirt, road oil, and other foreign material. Remove burrs that would prevent solid seating of the connected parts in the snug -tight condition. Do not paint the faying surfaces of slip- critical connections. Protect areas closer than 1 bolt diameter, but at least 1 inch from the edge of a hole and areas within bolt pattern from paint, including inadvertent ov erspray. for Highway Construction Page 343 of 715 Provide steel material within the grip of the bolt with no compressible material (e.g., gaskets , insulation within the grip). Ensure bolted steel parts fit solidly together. Bolted steel parts may be coated or uncoated. Ensure the slope of the surfaces of parts in contact with the bolt head or nut does not exceed 1:20 with respect to a plane normal to the bolt axis. Protect fasteners from dirt and moisture at the project site. Take only as many fasteners as are anticipated to be ins talled and t ightened during a work shift from protected storage. Return fasteners not used to the protected storage at the end of the shift. Do not clean fas teners of lubricant that is present in as -delivered condition. Clean and re- lubrica te fasteners for slip -critical connections that accumulate rust or dirt resulting from project site conditions, before installation. Use a n approved tension measuring device (e.g., Skidmore- Wilhelm calibrator) where bolts in slip - critical joints or connections subject to direct tension are being installed and tightened. Use the tension measuring device to confirm:
a.The suitability to satisfy the requirements in Table 504.03- 2 of the complete fastener assembly, including lubricati on if requir ed, to be used in the work.
b.Calibration of the wrenches.
c.The understanding and proper use of the method to be used by the bolting crew. Confirm the accuracy of the tension- measuring device through calibration by an approved testing agency at least annually in accordance with AASHTO T 67/ASTM E4. Calibrate wrenches daily in accordance with Idaho IR 12. The Engineer will inspect bolting and testing operations to determine the approved installation procedure is used and the cor rect tension has been achieved. The Engineer may reject testing operations completed. Store high- strength bolts , nuts, washers, and DTIs under cover to protect them from adverse conditions and ensure the identification of heat num ber or production lot number remain with each type of bolting parts. The Engineer will not accept bolting parts that are rusty, dirty, or have damaged threads. Before bolts are installed in the field or at the shop, subject the bolts to a rot ational -capacity test. Perform the rotational -capacity test on each rotational -capacity lot. Hardened steel washers are required as part of the test although they may not be required in the actual installation procedure. Provide bolt, nut, washer, and when required, D TI combinations as installed from the same rotational -capacity lot. Perform the rotational -capacity test as specified in 708.06.2.B.(4). Locate nuts wherever practical, on the side of the member that will not be visible from the traveled way. Locate nuts for bolts that will be partially embedded in concrete on the side of the member that will be encased in concrete. Turn the nut tight while the bolt is prevented from rotating. Provide each bolt with a hardened washer under the nut. An M 164 bolt may be reused 1 time if approved. The Department does not consider re- tightening a bolt loosened by the tightening of nearby bolts as reuse. To begin bolting connections, install and tighten to snug -tight enough bolts to bring parts into full contact with each other. for Highway Construction Page 344 of 71 5 After this initial tightening, install and bring to snug- tight remaining bolts in the connection. Then, beginning with bolts in th e most rigid part of the joint and working out to its free edges, systematically tighten bolts to specified tension. When bolts in a joint are tight, ensure each bolt carries at least the proof load in Table 504.03- 2. Table 504.03 -2 – Bolt Tension Minimum Bolt Tension, lb Bolt Size , inches Grade A325 Grade A490 0.5 12,050 14,900 0.625 19,200 23,700 0.75 28,400 35,100 0.875 39,250 48,500 1.0 51,500 63,600 1.125 56,450 80,100 1.25 71,700 101,800 1.375 85,450 121,300 1.5 104,000 142,500
2.Tightening Methods. Tighten using the DTI method as specified.
a.Direct Tension Indicator (DTI) Tightening.
1.Installation. Locate the DTI at the opposite end of the bolt from the part being tightened, where possible. When the DTI is used next to a slotted or oversized hole, place a hardened flat washer between the DTI and the part being tightened; do not reuse the DTI after tension has bee n applied to the bolt.
2.Bolt Tension. Meet the following:
a.Verify DTI performance before the start of installation of bolts in the bridge. Test in accordance with the procedure for verification and installation of high- strength bolts with DTIs. This procedure is in Appendix A6 of Report No. FHWA -SA-91-031 dated May 1991, revised April 1992.
b.Ensure the measured gap for DTIs is at 0.005 inch or less. Refusal of the feeler gauge in slots is d efined as a nil gap and may be cause for rejection by the Engineer. The Engineer may require bolts with nil gap to be removed from the work and the bolt thread examined at no additional cost to the Department. If no necking of the bolt thread is observed and the nut can run down the full length of the thread, then the bolt may be reinstalled with new DTIs. for Highway Construction Page 345 of 71 5 b. Turn-of-Nut Method. After bolts in the joint have been brought to snug- tightness, further tighten the nuts by the amount of rotation in Table 5 04.03- 3. Before final tightening and after snug- tightening, match- mark with crayon or paint the outer face of each nut and the protruding part of the bolt. To ensure this tightening method is followed, the Engineer will:
1.Observe as the Contractor installs and tightens bolts .
2.Inspect each match- mark. Place 3 bolts of the same grade, size, and condition as those under inspections individually in a device calibrated to measure bolt tension. Perform this calibration at least once each inspection day. Provide a washer under the part turned in tightening each bolt if washers are used on the structure. If washers are not used on the structure, provide material abutting for the part turned that is the same as specified for use on the structure. In the calibrated device, tighten each bolt to the specified tension. Apply the inspecting wrench to the tightened bolt to determine the torque required to turn the nut or head 5 degrees or approximately 1 inch at a 12-inch radius in the tightening direction. Take the average of the torque for the 3 bolts as the job- inspection torque. In the Engineer’s presence, inspect the tightened bolt using an inspection torque wrench. Select 10 percent or at least 2 of the tightened bolts on the structure represented by the test bolts at random in each connection. Apply the job- inspection torque to each with the inspecting wrench turned in the tightening direction. If this torque turns no bolt head or nut, the Engineer will accept the connection as being properly tightened, but if the torque turns 1 or more bolt heads or nuts, apply the job inspection torque to bolts in the connection. Tighten and re- inspect bolts whose head or nut turns at this stage. The Contractor may ret ighten the bolts in the connection and resubmit for inspection. for Highway Construction Page 346 of 71 5 Table 504.03 -3 – Turn -of-Nut Tightening Method (Nut Rotation(a) from Snug -Tight Condition) Bolt Length (a) (b) (c) (Measured from underside of head to extreme end of point) Both fac es at r ight angles to bolt axis One face at right angle to bolt axis, once face sloped no more than 1:20, without bevel washer Both faces sloped no more than 1:20 from right angle to bolt axis, without bevel washer < 4D 120° or 1/3 turn 180° or 1/2 turn 240° or 2/3 turn 4D to < 8D 180° or 1/2 turn 240° or 2/3 turn 300° or 5/6 turn 8D to 12D 240° or 2/3 turn 300° or 5/6 turn 360° or 1 turn
a.Nut rotation is relative to the bolt regardless of which element (nut or bolt) is being turned. Tolerances allowed: plus or minus 30° for final turns of 180° = 1/2 turn or less ; plus or minus 45° for final turns of 240° = 2/3 turn or more.
b.D = nominal bolt diameter of bolt being tightened.
c.When bolt length exceeds 12D, determine the rotation by actual tests that a suitable tension device simulates actual conditions.
M.Welding.
1.General. The Department requires weld fabrication to meet ANSI/AASHTO/AWS D1.5 Bridge Welding Code and interim revisions published by AASHTO as of the bid opening date except as modified in the rest of this section or as specified. Weld tubular members in accordance with the current edition, at the time of bid opening, of AWS D1.1 Structural Welding Code- Steel. Weld sheet steel not exceeding 1/8 inch in thickness in accordance with current addition, at the time of bid opening, of AWS D1. 3 Structural Welding Code- Sheet Steel. Weld aluminum in accordance with to the current edition, at the time of bid opening, of AWS D1.2 Structural Welding Code- Aluminum. Weld structural steel only to the extent specified. Do not weld, including tack and temporary welds, in the shop or field, unless the location of the welds is shown on the approved shop drawings or approved in writing. Obtain approval of shop plans before welding as specified in 504.01. Include in the shop plans procedures for welding, assembly, and heat -straightening or heat -curving.
2.Preheating. Comply with the preheat and interpass minimum temperatures in accordance with ANSI/AASHTO/AW S D1.5 Bridge Welding Code, Section 4. Show preheat temperatures on the shop drawings . Preheat web and flange plates, bearing stiffeners, bearing plates, and heavy sections (restrained when welded) to at least 250°F.
3.Welding Procedures. Perform welding on main members and attachments using only shielded metal arc, submerged arc, or stud welding. Weld butt splices and flange to web welds using th e for Highway Construction Page 347 of 71 5 automatic submerged arc process with uninterrupted continuous passes. The Contractor may request approval to substitute flux core welding in areas where automatic submerged arc welding is not feasible. The Engineer may approve complete joint penetration groove welds made by flux cored arc welding only after submittal of perfo rmance of the joint qualification tested in accordance with ANSI/AASHTO/AWS D1.5 Bridge Welding Code, Sections 5.7 and 5.12. Perform joint qualification tests and submit on each individual project. Submit the test coupons to an independent testing laboratory for testing. Use low- hydrogen electrodes in shielded metal -arc welding. Oven- dry flux for submerged- arc welding at 550°F for at least 2 hours, then store in ovens held at 248°F or more. If not used within 4 hours after removal from a drying or storage oven, re- dry the flux before use. Do not:
a.Weld with gas metal arc, electrogas, or electroslag methods.
b.Weld when ambient temperature is below 20°F.
c.Use coped holes in the web for welding butt splices in the flanges. Place tack welds so they are incorporated into the final weld. The same quality requirements apply for tack welds as the final welds except the discontinuities (e.g., undercut, unfilled craters, porosity) do not need to be removed before the final submerged arc welds. Make tack welds with electrodes meeting the requirements of the final welds and clean thoroughly. Provide multiple- pass tack welds with cascaded ends. If groove welds (web- to-web or flange- to-flange) have been rejected by the Engineer, they may be repaired twice. If a third failure occurs, trim the members at least ½ inch, if the Engineer approves, or replace the members at no cost to the Department. End welds at the end of the joint so sound welds are ensured. Whenever possible, do this by using extension bars and runoff plates configured to duplicate the joint detail being welded. Remove extension bars and runoff plates, on completion and cooling of the weld, and grind the ends of the welds smooth and fl ush to minimum surface finish of ANSI 125. Inspect 100 percent of the groove weld’s ends using dye penetrant or magnetic particle testing techniques and include splices in individual flanges and webs, transverse and longitudinal stiffeners, floor beams, and stringers. The Engineer may reject a member if there are arc strikes outside the weld joint or on metal not incorporated in a weld joint. Report arc strikes on surfaces carrying tensile or reversal stress in writing and submit report. Do not repair arc strikes on surfaces carrying tensile or reversal stress without written authorization. Accomplish repair of arc strikes by grinding the area containing the arc strike to a minimum surface finish of ANSI 125. Inspect the ground area by the magnetic - particle test (yoke method) and test for heat -affected- zone hardness. If the testing specified reveals cracking and/or hardness in excess of Rockwell C23, weld repair the area in accordance with ANSI/AASHTO/AWS D1.5 Bridge Welding Code.
4.Fillers. For multipass welds of unpainted AASHTO M 270 Grade 50W bridge steel, use filler metal meeting the requirements in the current AWS Specifications Table 4.2. When a bolted splice is used to join plates of differing thickness, do not weld filler plates used to account for the thickness difference into place, unless otherwise approved in writing. for Highway Construction Page 348 of 715 5. Shear Connectors. Weld shear connectors using a utomatically timed stud welding e quipment, unless otherwise approved in writing. For a welded shear connector longer than 8 inches, the Contractor may join 2 shorter shear connectors with full -penetration welds.
6.Welding Inspection. Compl y with current ANSI/AASHTO/AWS D1 .5 Bridge Welding Code for welding inspection procedures, techniques, and inspector qualification except as modified in this section or as specified. Use certified welding inspectors to inspect welds as follows:
a.Visual Inspection. Inspec t 100 percent of welds.
b.Radiographic Inspection. Inspect 100 percent of full -penetration groove welds subject to tension or reversal using radiographic inspection. Include those in the tension area of webs, inspect the greater of these two distances: 15 inches from the tension flange or 1/3 of the web depth from the tension flange.
c.Magnetic Particle Inspection. Inspect fillet welds and longitudinal butt welds in webs. Test using the yok e method only.
1.Flange- to-Web Connections. Inspect 100 percent of fillet welds in flange- to-web connections of built -up members until the Engineer accepts the Contractor’s record of quality control. After acceptance , inspect 30 percent of each weld with 10 percent of this inspection occurring at each end of the welds length. The remaining 10 percent will be randomly selected by the Engineer.
2.Boxed Members of Trusses. Inspect 100 percent of each fillet weld in boxed members of trusses.
3.End and Int ermediate Pier Diaphragms. Inspect 100 percent of each fillet weld in end and intermediate pier diaphragms.
4.Longitudinal Butt Weld in Web. Inspect each longitudinal butt weld in the web as specified for flange- to-web connections.
5.Stiffeners and Connection Plates. Inspect 30 percent of each fillet weld in transverse and longitudinal web stiffeners and connection plates with 10 percent occurring at each end of the weld. Inspect the remaining 10 percent randomly at points selected by the Engineer.
6.Miscellaneous Weldments. Inspect 100 percent of each fillet weld in miscellaneous weldments (e.g., bridge bearing assemblies ).
d.Ultrasonic Inspection. Inspect full -penetration groove welds ultrasonically.
1.Transverse Flange and Web Splices. Inspect 100 percent of each transverse groove weld.
2.End and Intermediate Pier Diaphragms. Inspect 100 percent of each groove weld.
3.Other Weldments. Inspect 100 percent of each groove weld in other weldments.
e.Dye-Penetrant or Magnetic -Particle Insp ection . Inspect 100 percent of the end of each groove weld at plate edges.
f.Other Inspection. Perform additional testing as specified or as directed. for Highway Construction Page 349 of 71 5 N. Erection.
1.Erection Marks. The Contractor may paint erection marks on surfaces to allow identification of members in the field that are to be painted in the field. For unpainted AASHTO M 270 Grade 50W, stamp erection marks with low stress intermittent dot steel die stamp in an area visible after completion of the structure. Ensure the maximum depth of the impression does not exceed 0.010 inch and the tool meets the requirements in Table 504.03- 4. Table 504.03-4 – Tool Specification Character Size (inch) Minimum Chara cter Face Radius (inch ) 1/8 0.007175 3/16 0.008200 1/4 0.010250 Ensure impressions are not near the edge of tensile- stressed plate members.
2.Alignment and Camber. Before beginning field bolting:
a.Adjust the structure to correct grade and alignment.
b.Regulate elevations of panel points (ends of floor beams).
c.Delay bolting at compression joints until adjusting the blocking to provide full and even bearing over the whole joint. On truss spans, the Engineer will allow a slight ex cess camber as the bottom chords are bolted. Correct camber and relative elevations of panel points before the top chord joints, top lateral system, and sway braces are bolted. Submit a diagram for each truss that shows camber at each panel point and display actual measurements taken as the truss is being assembled. Do not place forms, steel reinforcing bars, or concrete on steel spans until the girders in spans for a given st age of construction are completely erected with girder splices complete, cross frames installed, and temporary shoring released. After shoring is released and masonry plates have been grouted and before subsequent loading of the spans, measure the elevations along the tops of girders and floor beams at each tenth point of the spans. Determine and make the adjustment to the top- of-web to top -of-deck dimensions as necessary to meet the requirements of the plans and subm it the adjustments and elevations for approval.
3.Field Assembling and Bolting. To begin bolting a field connection or splice, install and tighten to snug- tight enough bolts to bring parts into full contact with each other before tighte ning these bolts to the specified minimum tension. Complete bolting a field connection using one of the following methods:
a.Method A. As erection proceeds, securely drift pin and bolt field connections and splices for each member as specified before the mass of the member can be released or the next member is added. Specify on field erection drawings pinning and bolting requirements that meet or exceed the following minimums: for Highway Construction Page 350 of 71 5 (1) Joints in Normal Structures. Fill 50 percent of the holes in a single field connection and 50 percent of the holes on each side of a single joint in a splice plate with drift pins and bolts . Pin 30 percent of the filled holes. Bolt and tighten 70 percent of the filled holes to snug- tight. Once these bolts are snug- tight, systematically tighten each bolt to the specified minimum tension. “Systematically tightened” means beginning with bolts in the most rigid part, which is usually the center of the joint, and working out to its free edges. Locate the fully tensioned bolts near the middle of a single field connection or a single splice plate.
2.Joints in Cantilevered Structures. Fill 75 percent of the holes in a single field connection and 75 percent of the holes on each side of a single joint in a splice plate with drift pins and bolts . Pin 50 percent of the filled holes. Bolt and tighten 50 percent of the filled holes to snug- tight. Once these bolts are snug- tight, systematically tighten each bolt to the specified minimum tension. Locate the fully tensioned bolts near the middle of a single field connection or a single splice plate. A joint in a cantilevered structure is defined as to be a field connection or splice that is on the unsupported or cantilevered side of a support. Joints that fit this description whether in final position or temporary position (e.g., during erection) are considered joints in cantilevered structures. Place drift pins throughout each fi eld connection and each field joint with the greatest concentration in the outer edges of a splice plate or member being bolted. To complete a joint, fill remaining holes of the field connection or splice plate with bolts and tighten to snug- tight. Once these bolts are snug- tight, systematically tighten each bolt to the specified minimum tension. After these bolts are tightened to the specified minimum tension, replace the drift pins with bolts, tightened to the specified minimum tension.
b.Method B. The Contractor may complete a field- bolted connection or splice in a continuous operation before releasing the mass of the member or adding the next member. Use drift pins to align the connection. For alignment drift pins, fill between 15 and 30 percent of the holes in a single field connection and between 15 and 30 percent of the holes on each side of a single joint in a splice plate. Once the alignment drift pins are in place, fill remaining holes wi th bolts and tightened to snug- tight starting from near the middle and proceeding toward the outer gauge lines. Once these bolts are snug- tight, systematically tighten these bolts to the specified minimum tension and then replace the drift pins with bolts. Tighten each of these bolts to the specified minimum tension. Place bolts with heads toward the outside and underside of the bridge. Install and tighten high- strength bolts before the falsework is removed. The Contractor may erect metal railings as erection proceeds, but do not bolt or adjust permanently until the falsework is released and the deck placed. Do not begin painting until the Engineer has inspected and accepted field bolting.
4.Surface Condition. As the structure is erected, keep steel surfaces clean and without dirt, concrete, mortar, oil, paint , grease, and other stain- producing foreign matter. Clean surfaces that have become stained as follows:
a.Clean painted steel surfaces by methods required for the type of staining. Submit the method to be used for Engineer approval. for Highway Construction Page 351 of 71 5 b. Weathering steel surfaces. After the deck is placed , remove concrete stains and other foreign matter from the exposed surfaces of structural steel members by power cleaning or other approved method that will provide a surface for the formation of patina (oxide coat ing).
504.04 Method of Measurement.
The Engineer will measure acceptably completed work as follows:
1.Structural metals will be by the pound, foot, or on a lump sum basis. Where payment is on a weight basis, the Engineer will compute the weights of rolled shapes and of structural steel plates on the basis of their nominal weights and dimensions.
2.Steel forgings will be by the pound based on the plan dimensions and the theoretical weight of 0.2833 pounds per cubic inch plan quantity .
3.Structural steel handrail, 2- tube curb mount rail, pedestrian/bicycle railing, and combination pedestrian/bicycle railing will be by the foot.
504.05 Basis of Payment .
The Department will pay for acceptable quantities as follows: Pay Item Pay Unit Steel Bridge ............................................................................................ LS Structural Steel ....................................................................................... lb or LS Steel Forgings ........................................................................................ lb Structural Steel Handrail ......................................................................... FT 2-Tube Curb Mount Rail ......................................................................... FT 3-Tube Curb Mount Rail ......................................................................... FT Pedestrian/Bicycle Railing ...................................................................... FT Combination Pedestrian/Bicycle and Traffic Railing ............................... FT The Department will pay using plan quanti ties as specified in 109.01. The work associated with the making of the test coupons is i ncidental . for Highway Construction Page 352 of 71 5 SECTION 505 – PILING
505.01 Description.
Provide and drive piles, including test piles.
505.02 Materials.
Provide materials as specified in: Concrete ...................................................................................................................................... 502 Steel H -Piles ............................................................................................................................ 708.08 Steel Shell Piles ....................................................................................................................... 708.30 Timber Piles ............................................................................................................................. 710.05
505.03 Construction Requirements.
A.General. Provid e pile type and size as shown on the bridge plans. Drive test piles with the same pile driving hammer make, model, and size as will be used for production pile driving. Do not drive test piles with a vibratory hammer, unless specified in the contract or as directed. Notify the Engineer at least 7 calendar days before driving each test pile. The Engineer will require up to 2 business days after receiving each test pile record (ITD 0970) and corresponding signed and sealed CAPW AP Analysis Report to evaluate each test pile result, and provide the production pile driving criteria and revised estimated pile length. Drive test piles as shown in the bridge plans or as directed. If the required bearing capacity is not achieved when the test pile is driven as shown in the bridge plans, continue driving the test pile until the required bearing capacity has been achieved as determined by the Engineer. Complete the foundation excavation before driving piles . Drive production piles as shown in the bridge plans or as directed. If the required highest pile tip elevations or minimum penetrations cannot be achieved using a hammer with higher energy, then removing and replacing the pile, driving an adjacent pile, or predrilling may be required. Pile restriking may be required if the pile does not have the design capacity at the end of initial driving. Restrike piles for 4 inches of penetration or as di rected, with the hammer that has been warmed up by applying at least 20 blows to another pile or to a timber mat placed on the ground. Provide a suitable light for shell pile inspection. Piles must achieve the required pi le driving criteria through 2 consecutive, 1- foot or 1 -inch penetration intervals.
B.Helmet Assembly. Use a helmet assembly with a suitable hammer cushion for driving piles. Fit the helmet assembly closely to the pile tops. Provide a helmet assembly design that has been proven satisfactory and is properly sized for driving the piles.
Source: Idaho Standard Specifications for Highway Construction, 2023 Edition. Pages 370–387 of 768.