4195.01LEAD
Furnish sheet lead for bearing areas meeting the requirements of ASTM B 29. 4195.02 A.
NEOPRENE BEARING PADS. Fabricate the elastomer portion of the pad from new neoprene. Cast pads under heat and pressure. They may be individually molded to the size and shape specified in the contract documents, or they may be cut from pressure cast stock. Ensure cut edges are at least as smooth as ANSI 250 finish. Variations in dimensions shown are not to exceed the values in Table
4195.021:
Table 4195.02-1: Maximum Dimension Variations Nonlaminated Laminated
Thickness
- 0 inch, + 0.1181 inch
- 0 inch, + 0.125 inch
Width
- 0.125 inch, + 0.25 inch
- 0.125 inch, + 0.25 inch
Length
- 0.125 inch, + 0.25 inch
- 0.125 inch, + 0.25 inch
B.
Furnish pads in one piece, not laminated in any manner, unless specified otherwise in the contract documents.
C.
If pads are laminated, they are to have alternate laminations of neoprene and rolled steel sheets molded together as a unit. Unless required otherwise, meet the following requirements for pads: 1.
The thickness of metal laminations: in the range of 14 gage to 1/8 inch inclusive.
2.
Outer laminations of neoprene: 1/4 inch.
3.
Edges of all metal laminations covered by a minimum of 1/8 inch of neoprene, except at laminate restraining devices and around holes that will be entirely closed on the finished structure.
Bearing Pads
D.
4195.02
For the neoprene in laminated pads, meet the requirements in Table
2, as specified by the Engineer. Compounds of nominal hardness
between the values shown may be used, and test requirements interpolated. For homogeneous pads, the neoprene is to meet the requirements of Table
2, using a durometer hardness of 70 unless the Engineer specifies
otherwise.
ASTM Standard D 2240
Table 4195.02-2: Neoprene Requirements Physical 50 Duro. 60 Duro. Properties Hardness Tensile Strength, minimum psi
70 Duro.
50 + or - 5
60 + or - 5
70 + or - 5
2250
2250
2250
400
350
300
+15
+15
+15
-15
-15
-15
-40
-40
-40
No Cracks
No Cracks
No Cracks
D 412 Ultimate elongation, minimum % Heat Resistance Change in durometer hardness, maximum points D 573 70 hr. 212°F
D 395 Method B
D 1149 20% strain
D 429, B
Change in tensile strength, maximum % Change in ultimate elongation, maximum % Compressive Set 22 hours @ 212°F, maximum % Ozone 100°F ± 2°F, 100 hours 100 pphm ozone in air by volume Adhesion Bond made during vulcanization minimum lbs. per inch
Low Temperature D 746 No No No Test Procedure Failure Failure Failure Brittleness at -40ºF B Ensure laminates are fabricated from rolled mild steel sheets conforming to ASTM A 1011, Grade 33; Grade 36, Type 1 and 2; or Grade 40, unless the Engineer specifies otherwise.
E.
When test specimens are cut from a finished product, a 10% variation in physical properties will be allowed.
4196.01
Engineering Fabrics