Section 717 — Structural Metal

717.01Structural Steel.

(a)Structural carbon steel. Conform to the following:

(1)Primary bridge members AASHT O M 270, Grade 36T or 50ST

(2)Fracture critical bridge members AASHTO M 270, Grade 36F or 50SF

(3)Hollow structural sections ASTM A500 , Grade B or C, ASTM A618, ASTM A847, or ASTM A1085

(4)Other shapes, plates, and bars AASHTO M 270, Grade 36 or 50S

(b)High -strength low -alloy structural steel. Conform to the following:

(1)Primary bridge members and w elded members AASHTO M 270, Grade 50T or 50WT

(2)Fracture critical bridge members and fracture critical welded members AASHTO M 270, Grade 50F or 50WF

(3)Other shapes, plates, and bars AASHTO M 270, Grade 50 or 50W

(c)HPS. Conform to the following:

(1)Primary bridge members AASHTO M 270, Grade HPS 50WT, HPS 70WT, or HPS 100WT

(2)Fracture critical bridge members AASHTO M 270, Grade HPS 50WF, HPS 70WF, or HPS 100WF

(3)Other shapes, plates, and bars AASHTO M 270, Grade HPS 50W, HPS 70W, or HPS 100W

(d)Bolts and nuts. Conform to ASTM F1554, Grade 36 or 55, or ASTM A307 as shown in the plans. Provide nuts conforming to ASTM A563 for appropriate grade and size of anchor bolt. Lubricate galvanized nuts with a lubricant containing a visible dye.

(e)High -strength bolts, nuts, and washers. Provide bolts conforming to ASTM F3125 or ASTM F3148 as specified. If not provided as an assembly (ASTM F3125 Grades F1852 and F2280, or ASTM F3148), provide nuts conforming to ASTM A 563, Grade DH or DH3, with the S1 Supplementary Lubricant Requirement , and provide washers conforming to ASTM F436. Use Type 3 bolts, nuts, and washers to connect uncoated weathering steel components. Use Type 1 or 3 in other scenarios. Provide fastener assembly coatings conforming to ASTM F3125 Annex A1 or ASTM F3148 Table 1. If hot-dip or mechanically galvanized coatings are used, use a lubricated nut dyed blue. 841 Provide fastener assemblies (bolt, nut, and washers) that have been rotation -capacity tested by the manufacturer and fastener components that have been assigned a rotation -capacity lot number.

(f)Rockfall protection hardware. Provide wire rope clips that meet Federal Specification FF-C-450G, wire rope thimbles that meet Federal Specification FF-T- 276C, and shackles and swivels that meet Federal Specification RR-C-271D. Provide wire rope clips, thimbles, shackles, and swivels sized for wire rope diameters of 1 inch, ¾ inch, 9/16 inch, ½ inch, 5/16 inch, and ¼ inch. Galvanize all other hardware according to AASHTO M 232 or ASTM A153.

(g)Rockfall protection nuts and washers. Provide nuts conforming to ASTM A563 or ASTM A536 that can develop 100 percent of the minimum ultimate tensile strength (MUTS) of the bar. Provide anchor nuts that meet the specified strength requirement while allowing a maximum 5 -degree misalignment between the nut and the bearing plate. Provide hardened washers conforming to ASTM F436, ASTM A536, or ASTM A47, and plate washers conforming to ASTM A572, Grade 50. Galvanize nuts and washers after fabrication according to AASHTO M 232, ASTM A153, or ASTM F2329.

(h)Anchor plates. Provide anchor plates conforming to ASTM A572 Grade 50, hot -dipped galvanized according to AASHTO M 232, and with the following characteristics:

(1)Steel plate thickness of at least ¼ inch.

(2)Bent edges to provide load-bearing points extending through the mesh.

717.02Steel Forgings. Conform to AASH TO M 102, Classes C, D, F, and G.

717.03Pins and Rollers. Provide pins and rollers more than 9 inches in diameter from annealed carbon steel forgings conforming to AASHTO M 102, Class C. Provide pins and rollers no more than 9 inches diameter from either annealed carbon steel forgings conforming to AASHTO M 102, Class C or cold finished carbon steel shafting conforming to AASHTO M 169, Grade 1016 to Grade 1030 inclusive, with a minimum Rockwell Scale B hardness of 85. The hardness requirement may be waived if the steel develops a tensile strength of 70,000 pounds per square inch and a yield point of 36,000 pounds per square inch. For pin threads, conform to ANSI B1.1, Unified Inch Screw Threads (UN, UNR, and UNJ Thread Forms), Class 2A. Thread pin ends wit h a diameter of at least 1⅜ inches with 6 threads to the inch.

717.04Castings.

(a)Steel castings. Conform to AASHTO M 103, Grade 70-36.

(b)Chromium alloy steel castings. Conform to AASHTO M 163, Grade CA15.

(c)Gray iron castings. Conform to AASHTO M 105, Class 30B or 35B.

(d)Malleable iron castings. Conform to ASTM A47, Grade 32510.

717.05Welded Stud Shear Connectors. Conform to AASHTO M 169 and AASHTO, LRFD Bridge Construction Specifications, Article 11.3.3, Welded Stud Shear Connectors.

717.06Steel Pipe. Provide galvanized steel pipe conforming to ASTM A53, Type F, standard weight class, and plain ends for the designation specified.

717.07Galvanized Coatings. Galvanize steel according to AASHTO M 111. 717.08 Steel Grid Floors . Conform to AASHTO M 270, Grade 36. Galvanize according to AASHTO M 111 unless coating is specified. 717.09 Bearings.

(a)Elastomeric bearings, plain or laminated. Conform to AASHT O M 251.

(b)High load rotational spherical bearings. Conform to ASTM D5977.

(c)Polytetrafluoroethylene surfaces for bearings. Conform to the following:

(1)PTFE resin . Provide virgin PTFE resin material conforming to ASTM D4894 or ASTM D4895. (2) Filler material. Provide milled glass fibers, carbon, or other approved inert material.

(3)Adhesive material. Provide epoxy resin adhesive conforming to AASHTO M 235.

(4)Unfilled PTFE s heet. Provide unfilled PTFE sheet made from PTFE resin. Conform to Table 717-1.

(5)Filled PTFE sheet. Provide filled PTFE sheet made from PTFE resin uniformly blended with filler material. Do not exceed 15 percent filler content usin g fiberglass or 25 percent filler content using carbon fibers. For filled PTFE sheets containing glass fibers or carbon, conform to Table 717-1.

(6)Fabric containing PTFE fibers. Provide fabric made from oriented multifilament PTFE fluorocarbon and other fibers or from a mixture of PTFE fibers made from twisted, slit PTFE tape and other fibers according to the manufacturer ’s recommendations. Conform to Table 717-1. Table 717-1

Polytetraflu oroethylene Sheeting

Property ASTM

Method Sheet

Unfilled Sheet

with 15 percent

Glass Fibers Sheet

with 25 percent

Carbon Fibers Woven

Fabric

Tensile strength,

minimum D638 or D2256 2800 psi 2000 psi 1300 psi 24,000 psi

Elongation,

minimum D638 or D2256 200% 150% 75% 35%

Specific gravity,

minimum D792 2.16±0.03 2.20±0.03 2.10±0.03 – Melting point D4591 623±2 ºF 621±18 ºF 621±18 ºF – 843 (7) Interlocked bronze and filled PTFE components. Provide a phosphor bronze plate conforming to ASTM B100 with a 0.010 inch thick , porous bronze surface layer conforming to ASTM B103 into which is impregnated a lead -PTFE compound. Overlay the surface with compounded PTFE at least 0.001 inch thick.

(8)Lubricants. Use lubricants consisting of a combination of solids that do not react chem ically or electrolytically with the PTFE and its mating surface and remain stable in the environmental conditions expected at the bridge site.

(9)Surface treatment. For epoxy bonding, factory treat one side of the PTFE sheet with a sodium naphthalene or sodium ammonia process.

(10)Stainless steel mating surface. Conform to ASTM A264, Type 304 and the following:

(a)Thickness 0.0598 inch minimum, if maximum dimension is 12 inches or less 0.0897 inch minimum, if maximum dimension exceeds 12 inches

(b)Surface finish 8 µin root mean square maximum Polish or roll stainless steel mating surfaces as necessary to a finish at least 20 micro -inches.

717.10Aluminum Alloy for Bridge Rail. For extruded bars, rods, shapes, and tube s, conform to ASTM B221, alloy 6061-T6. For rolled or extruded structural shapes, conform to ASTM B308, alloy 6061- T6.

717.11Aluminum Bolt Heads and Nuts . Conform to American standard heavy hexagon ANSI B18.2. For threads, conform to American standard coarse series, Class 2 fit, ANSI specification B1.1, Unified Inch Screw Threads (UN, UNR, and UNJ Thread Forms).

717.12Aluminum Welding Wire. Conform to Table 717-2. Table 717-2

Aluminum Welding Wire

Alloy Series Specification Wire

3xxx and 6xxx AWS A5.10 ER 4043 3xxx, 5xxx, and 6xxx ER 5356 5xxx and 6xxx ER 5556 or ER 5183