4195 Bearing Pads

4195.01 LEAD.
Sheet lead for bearing areas shall meet requirements of ASTM B 29 for any type.

4195.02 NEOPRENE BEARING PADS.
The elastomer portion of the pad shall be new neoprene. Pads shall be cast under heat and pressure, and may be individually molded to size and shape specified in the contract documents or they may be cut from pressure cast stock. Cut edges shall be at least as smooth as ANSI 250 finish. Variations in dimensions shown shall not exceed the following:

Nonlaminated Laminated

Thickness, + 1/16 inch
(2 mm) + 1/8 inch
(3 mm)

Width, - 1/8 inch, + 1/4 inch
(-3 mm, + 6 mm) - 1/8 inch, + 1/4 inch
(-3 mm, + 6 mm)

Length - 1/8 inch, + 1/4 inch
(-3 mm, + 6 mm) - 1/8 inch, + 1/4 inch
(-3 mm, + 6 mm)

Pads shall be furnished in one piece, not laminated in any manner, unless otherwise specified in the contract documents.

Laminated pads shall have alternate laminations of neoprene and rolled steel sheets molded together as a unit. Unless otherwise required, pads shall meet the following requirements:

The thickness of metal laminations shall be in the range of 14 gauge to 1/8 inch (1.5 mm to 3.5 mm) inclusive. Outer laminations of neoprene shall be 1/4 inch (6 mm). Edges of all metal laminations shall be covered by a minimum of 1/8 inch (3 mm) of neoprene, except at laminate restraining devices and around holes that will be entirely closed on the finished structure.

For laminated pads the neoprene shall meet the requirements in Table B, as specified by the Engineer. Compounds of nominal hardness between the values shown may be used, and test requirements interpolated. For homogeneous pads, neoprene shall meet requirements of Table B, with a durometer hardness of 70 shall be used unless otherwise specified by the Engineer.

When test specimens are cut from a finished product, a 10% variation in physical properties will be allowed.

TABLE B
ASTM
Standard Physical Properties 50 Duro. 60 Duro. 70 Duro.
D 2240 Hardness 50 + or - 5 60 + or - 5 70 + or - 5
D 412 Tensile Strength, minimum psi (MPA)

Ultimate elongation, minimum % 2250
(15.5)

400 2250
(15.5)
350
2250
(15.5)
300

D 573
70 hr.
212°F (100°C)
Heat Resistance

Change in durometer hardness, maximum points
Change in tensile strength, maximum %
Change in ultimate elongation, maximum %

+15
-15
-40

+15
-15
-40

+15
-15
-40

D 395
Method B Compressive Set

22 hours @ 212°F (100°C), maximum %

35

35

35

D 1149
20% strain Ozone

100°F ą 2°F (38°C ą 1°C), 100 hours
100 pphm ozone in air by volume

No
Cracks

No
Cracks

No
Cracks

D 429, B Adhesion

Bond made during vulcanization
minimum lbs. per inch (N/mm)

40 (7)

40 (7)

40 (7)

D 746
Procedure B Low Temperature Test

Brittleness at -40°F (-40°C)
No
Failure
No
Failure
No
Failure
Laminates shall be rolled mild steel sheets conforming to ASTM A 1011/A 1011M, Grade 33; Grade 36, Type 1 and 2; or Grade 40, unless otherwise specified by the Engineer.

	Nonlaminated	Laminated
Thickness,	+ 1/16 inch (2 mm)	+ 1/8 inch (3 mm)
Width,	- 1/8 inch, + 1/4 inch (-3 mm, + 6 mm)	- 1/8 inch, + 1/4 inch (-3 mm, + 6 mm)
Length	- 1/8 inch, + 1/4 inch (-3 mm, + 6 mm)	- 1/8 inch, + 1/4 inch (-3 mm, + 6 mm)

TABLE B
ASTM Standard	Physical Properties	50 Duro.	60 Duro.	70 Duro.
D 2240	Hardness	50 + or - 5	60 + or - 5	70 + or - 5
D 412	Tensile Strength, minimum psi (MPA) Ultimate elongation, minimum %	2250 (15.5) 400	2250 (15.5) 350	2250 (15.5) 300
D 573 70 hr. 212°F (100°C)	Heat Resistance Change in durometer hardness, maximum points Change in tensile strength, maximum % Change in ultimate elongation, maximum %	+15 -15 -40	+15 -15 -40	+15 -15 -40
D 395 Method B	Compressive Set 22 hours @ 212°F (100°C), maximum %	35	35	35
D 1149 20% strain	Ozone 100°F ą 2°F (38°C ą 1°C), 100 hours 100 pphm ozone in air by volume	No Cracks	No Cracks	No Cracks
D 429, B	Adhesion Bond made during vulcanization minimum lbs. per inch (N/mm)	40 (7)	40 (7)	40 (7)
D 746 Procedure B	Low Temperature Test Brittleness at -40°F (-40°C)	No Failure	No Failure	No Failure
Laminates shall be rolled mild steel sheets conforming to ASTM A 1011/A 1011M, Grade 33; Grade 36, Type 1 and 2; or Grade 40, unless otherwise specified by the Engineer.