SECTION 713 - STRUCTURAL STEEL AND RELATED MATERIAL
713.01 Structural Steel Highway bridge steel shall meet the r equirements of
AASHTO M 270.The grade of steel shall be as specified on the plans. Main load-carrying components subject to tensile stresses or stress reversal shall meet the notch toughness requirements in AASHTO M 270M, Table 10, Zone 2, for non-fracture critical steel or Table 11, Zone 2 for fracture critical steel. Frequency of tension tests shall comply with the requirements of S1. Impact test sampling and testing procedures shall be in accordance with AASHTO T 243 M/T 243 and AASHTO T 244. 7-42 Steel for ancillary bridge products and steel structures shall conform to AASHTO M 270 or one or more of the following: ASTM A 36 ASTM A 572 ASTM A 588 ASTM A 53 ASTM A 500 ASTM A 595 Grade C ASTM A 786 ASTM A 847 ASTM A 992 Ancillary bridge products shall be as described below:
a.bearings
b.drainage components
c.expansion devices (gland seal, compression seal, finger jo int)
d.modular expansion devices
e.steel bridge rail
f.catwalks and inspection walkways
713.02 High Strength Bolts Bolts shall conform to the requirements of ASTM F3125,
Grade A 325, Type 1 or Type 3. Type 3 bolts shall be supplied for all structures utilizing unpainted AASHTO M 270Mweathering steel. Nuts shall meet the requirements of AASHTO M 291 or AASHTO M 292. Circular and beveled washers shall conform to the requirements of AASHTO M 293. Direct Tension Indicators (DTI’S) shall conform to the requirements of ASTM F 959. DTI’s for use with painted steel shall have a plain “as fabricated” finish. DTI’s for use with unpainted steel shall be galvanized to the requirements of AASHTO M 298 Class 50, Type I and have a fusion-bonded epoxy coating. DTI’s used with galvanized steel, metalized steel and steel coated with a zinc-rich primer shall be galvanized to the requirements of AASHTO M 298 Class 50, Type I. “Twist Off” Type Tension Control Structural Bolt/Nut/Washer Assemblies shall meet the requirements of ASTM F3125, Grade F1852. Bolts, nuts and washers specified to be galvanized may be galvanized by either hot dip galvanizing to the requirements of AASHTO M 232 Class C or mechanically galvanized to the requirements of AASHTO M 298 Class 50, Type I. All fastener (bolts and nuts), whether black or galvanized, shall be coated with a suitable lubricant. Galvanized nuts shall be lubricated with a lubricant containing a visible dye. 7-43 Each lot of bolts, nuts, washers and DTI’s shall be tested by the manufacturer in accordance with the tests tabulated in Table 1 - Test Schedule. The testing frequency for bolts, nuts and washers from each shipping lot of fasteners shall be as specified in the applicable AASHTO/ASTM Standard Specifications. The testing frequency for each production lot of DTI’s shall be as specified in ASTM F 959. TABLE 1 - Test Schedule* Bolts Tensile Strength (Wedge Test) Proof Load Hardness Coating Thickness ASTM F 606 ASTM F 606 ASTM F 606 AASHTO M 298 Nuts Proof Load Hardness Coating Thickness ASTM F 606 ASTM F 606 AASHTO M 298 Washers Hardness Coating Thickness ASTM F 606 AASHTO M 298 DTI’s Coating Thickness Compression Load AASHTO M 298 ASTM F 959 *The supplier(s) shall submit test reports for all testing requ ired in this Table. Test reports shall contain, in addition to the test results, the name and ad dress of the testing agency, the manufacturer, lot tested, and Mill Test Reports for all steel u sed in the manufacture of the fastener assemblies and DTI’s. The supplier shall perform, or cause to be performed a Rotational Capacity Test (RCT) for every production lot combination of bolts, washers and nuts. Each combination shall be designated with a unique RCT lot number. The test results shall be furnished to the Engineer.
713.03 Preformed Pads Preformed pads shall be made with new unvulcanized rubber
and unused fabric fibers and shall be approximately ⅛ inch thick after compression and vulcanizing with a proportion of fiber content sufficient to maintain strength and stability. The surface hardness shall be 85 to 95 Shore A Durometer. The ultimate breakdown limit of the pad under compressive loading shall be no less than 10,000 psi.
713.04 Bronze or Copper-Alloy Bearing and Expansion Plates Br onze bearing and
expansion plates shall conform to the requirements of AASHTO M 107 (ASTM B 22), Alloy No. 911 and copper alloy bearing and expansion plates shall conform to the requirements of AASHTO M 108, (ASTM B 100) Alloy No. 510 or 511, unless otherwise specified. The bearing surface(s) subject to sliding action shall be provided with trepanned recesses (not grooves) filled with a lubricating compound. The lubricating compound shall consist of graphite and metallic substances with a lubricating binder capable of withstanding the atmospheric elements. The compound shall be pressed into the recesses to form dense, non-plastic lubricating inserts. The lubricating area shall comprise between 25 percent and 35 percent of the total area of the plate subject to sliding action. The sliding surface(s) shall be planed parallel to the 7-44 prevailing direction of movement of the structure and subsequently polished, unless detailed otherwise.
713.05 Cold-finished Carbon Steel S hafting Cold-finished carbon steel shafting
shall conform to the requirements of AASHTO M 169. Grade Designation 1021-1030 inclusive, cold drawn, either semi-killed or fully-killed, shall be furnished unless otherwise specified.
713.06 Castings Gray iron castings, for use other than for dr ainage castings,
(Section 712.07) shall conform to the requirements of AASHTO M 105. Class Number 35 shall be furnished unless otherwise specified. Malleable iron castings shall conform to the requirements of A STM A 47. Grade Number 32510 shall be furnished unless otherwise specified. Carbon-Steel Castings for General Applications shall conform t o the requirements of AASHTO M 103. The grade 70-36 of steel shall be used unless otherwise specified. Castings shall be true to pattern in form and dimensions, free from pouring faults, sponginess, cracks, blow holes and other defects in positions affecting their strength and value for the service intended. Castings shall be boldly filleted at angles and the arrises sh all be sharp and perfect. All castings must be sand blasted or otherwise effectively cle aned of scale and sand to present a smooth, clean, and uniform surface.
713.07 Metal Bin Type Retaining W all The metal for bin type retaining wall
members shall be galvanized and shall conform to the applicable requirements of AASHTO M 36. When fiberglass, aramid or carbon graphite fiber coating is sp ecified, the galvanized metal sheets used to form the retaining wall, except the base plates and connecting channels, shall additionally be coated on both sides with a layer of fiberglass, aramid or carbon graphite fibers applied in sheet form by pressing it into the molten spelter. Immediately after the metallic bond has solidified the fibers shall be thoroughly saturated with a bituminous saturant conforming to the following requirements: Penetration at 77 °F, 3.5 oz, 5 sec. 0.14 - .018 inches Loss on heating at 325°F, 1.75 oz, 5 hrs Not more than 1.5 percent Flash point (open cup) Not less than 440°F Penetration at 77 °F, 3.5 oz, 5 sec., of residue after heating at 325°F, as compared with penetration of asphalt before heating Not less th an 70 percent Insoluble in carbon disulfide Not more than 2 percent 7-45 Testing shall be in accordance with methods specified in AASHTO M 20. Whenever possible in the manufacture of the units, a minimum f orming radius of 1 inch is to be maintained. All units that are formed with less than 1 inch radius shall be hot- dipped galvanized after forming. Bolts shall conform to the requirements of ASTM F 568 Class 4. 6 (ASTM A_307) and galvanized in accordance with AASHTO M 232.
713.08 Steel Extrusions Material for steel extrusions for exp ansion devices shall be
ASTM A 36/A 36M, ASTM A 588/A 588M, or ASTM A 242/A 242M, except that ASTM A 242/A 242M shall not be used for extrusions that are to be welded.
Referenced in this section
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Source: Standard Specifications — Highways and Bridges, 2020 Edition. Pages 746–750 of 817. View official source ↗