7-109 SECTION 731 – BEARING PADS FOR STRUCTURES
731.01 BEARING PADS . Bearing pads shall be manufactured from all -new materials comprised of high -
quality elastomer with a random distribution of synthetic fibers in proper proportion to maintain strength and stability. The finished product shall withstand a compressive load perpendicular to the plane of laminations of 7,000 psi. The surface shall have a hardness of 80 (± 10) using a Shore A durometer, in accordance with the requirements of ASTM D2240 .
731.02 ELASTOMERIC MATERIAL . Elastomeric material shall conform to the AASHTO LRFD Bridge
Construction Specifications, Section 1 8 and AASHTO M 251 , Durometer Grade 50, Low Temperature Brittleness Grade 4, unless otherwise specified . Elastomeric material shall have a shear modulus of 110 psi, unless otherwise specified. The resul ting product shall be free of porous areas, weak sections, bubbles, foreign matter, or other defects affecting serviceability. Testing of elastomeric material will be waived for bearings that will be encased in concrete in the final work.
731.03 STAINLESS STEEL . Stainless steel shall conform to the requirements of the AASHTO LRFD Bridge
Design Specifications, Section 14 and the AASHTO LRFD Bridge Construction Specifications, Section 18 . Stainless steel used as a mating surface with polytet rafluoroethylene (PTFE) material and incorporated in bearing devices shall conform to the requirements of ASTM A240, Type 304.
731.04 PTFE MATERIAL . Polytetrafluoroethylene (PTFE) material incorporated in bearing devices shal l
be all -new material with a minimum thickness of 1/8 inch and conforming to the requirements of the AASHTO LRFD Bridge Design Specifications, Section 14.7.2 and the AASHTO LRFD Bridge Construction Specifications , Section 18 . 7-110 SECTIO N 732 – RAILIN G MATERIALS 732.0 1 META L HAND RAILING . Material for metal hand railing and sleeves shall conform to the requirements of ASTM A53 or ASTM A500 , Grade B. 732.0 2 ALUMINU M BRIDG E RAILING .
a.Aluminum Alloy . Aluminum alloy for aluminum bridge railing, including hand railing, shall conform to the requirements of Subsection 715.0 2.
b.Stainless Steel Bolts, Nuts, Washers, and Set Screws . Bolts and washers for post, railing , and offset block connections shall conform to the requirements of ASTM F593, Alloy Group 1, Condition AF, Alloy 304 and its supplementary requirements for S5. Nuts shall conform to the requirements of ASTM F836M, Property Class A1 -50, Condition AF, Alloy 304 and ASTM F594, Alloy Group 1, Co ndition AF, Alloy 304. Stainless steel set screws for use in aluminum bridge railing connections shall conform to the requirements of ASTM F880, Property Class A1 -70, Condition CW, Alloy 304 and ASTM F880, Alloy Group 1, Condition CW, Alloy 304. Stainless steel anchor bolts and washers shall conform to the requirements of ASTM F593, Alloy Group 1, Condition CW, Alloy 304. Heavy hex stainless steel nuts for stainless steel anchor bolts shall conform to the requirements of ASTM F836M, Property Class A1-70, Condition CW, Alloy 304 and ASTM F594, Alloy Group 1, Condition CW, Alloy 304.
c.Structural Carbon Steel . Structural carbon steel for anchor channel bars, approach railing posts, offset brackets, and anchor bolt sleeve bases shall conform to the r equirements of AASHTO M 270, Grade 250 (Grade 36) or ASTM A36.
d.Steel Pipe . Steel pipe for anchor bolt sleeves shall conform to the requirements of Subsection 740.0 4.
e.Anchor Bolts, Nuts, and Washers . Anchor bolts, nuts, and washers shall conform to the requirements of Subsection 714.07 .
f.Fabric Pads . Fabric pads for aluminum posts shall conform to the requirements of Subsection
731.01 or Subsection 731.02 .
g.Aluminum Impregnated Caulking Compound . Aluminum filled silicone sealant shall conform t o the requirements of Subsection 707.1 1.
Source: Vermont Standard Specifications for Construction, 2024 Edition. Pages 1261–1261 of 1,380.