Natural Rubber Elastomeric Bearing Pads

Benchmark has a large stock of Natural Rubber Elastomeric Bearing Pad material and can offer expedited processing. 
Natural Rubber Bearings Canada

TBF High Density Thermal Break Foam

Benchmark Stocks plain and shimmed bearings are available in standard Shore A durometers of 50, 60 or 70 based on state and/or AASHTO Code, Section 18, natural rubber or neoprene. For economy, a commercial grade is also available.

PTFE-surfaced neoprene-backed slide bearings are also available. Type CSA material is recommended bonded to a 10-gauge steel laminate which has been bonded to neoprene.

If minimum dead load pressure is less than 200 psi, it is recommended that the elastomer be epoxy-bonded to concrete. If being welded on steel, an 8 gauge tack plate is recommended for positive reinforcement and ease of application. The maximum temperature at a neoprene bearing is 200° F.

Natural Rubber Elastomeric Bearing Pad Features

Elastomeric Bearing Pads Canada

elastomeric bearings are fabricated of natural rubber or neoprene. Designed and sized to meet the needs of your structure, these bearings are rigid enough to transmit the necessary loads and flexible enough to permit the rotation and movement required by the structure. They can also be used for vibration and earthquake-motion control applications.

Natural Rubber Elastomeric Bearings are made of an elastomer containing either natural rubber as the basic polymer. They are available primarily in 55 durometer hardness (Shore A) and meet the CAN/CSA-S6-06 standard, or in hardness meeting Ontario OPSS 1202. They can be molded or cut (from standard rolls) into a wide range of dimensions and thicknesses.

CAN/CSA-S6-06 Bearing Pad standard Test Results / Requirements

Property Test Method Results
Rubber Type = Natural
Hardness, Shore A D2240 55 +- 5
Tensile Strength, MPa D412 Minimum 17.0
Ultimate Elongation, % D412 Minimum 400
Specified Test Temperature D573 70h at 70 degrees C
Change in Hardness, Shore A D573 Maximum + 10
Change in Tensile Strength, % D573 Maximum -25
Change in Ultimate Elongation, % D573 Maximum - 25
Specified Test Temperature D395 22 h at 70 Degrees C
Residual Compression, % D395 Maximum 25
Mounting Procedure A D1149 22 pphm, 48 h
20% Strain, 40 +- 2 Degrees C D1149 No cracks
Bond Between Steel and Elastomer Laminate, N,mm D429 Minimum 7.0
Brittleness at -10 degrees C D746 No Failure
Low Temperature Crystallization Increase in Hardness, Shore A D2240 168 h at -25 Degrees C Maximum + 15"

Data given is from CAN/CSA-S6-06

Other hardness and other grades are available to meet AASHTO, AREMA or other standards as per engineer requirements.

DESIGN SHAPE FACTOR(S)

The behavior of an elastomeric bearing under compression is influenced by the shape factor (S), which is defined as the ratio between the loaded area of the bearing and the area that is free to bulge:

MAXIMUM SHEAR DEFORMATION

Maximum shear deformation of a plain bearing pad is limited to 50% of
the total pad thickness

These maximum pressures should be limited only to meet the two following load combination requirements:

Compressive load without rotation

For plain bearing pads used under compressive load only, i.e. without
rotation, the maximum pad thickness can be obtained from a graph
relating the average service compressive load to the pad shape factor.
It should be noted that a positive attachment should be specified for
minimum compressive loads of less than 1.5 MPa at SLS (Serviceability Limit State).

Compressive load with rotation
For plain bearing pads used under compressive loads and rotation, the maximum pad thickness should be such that under all service load combinations, the maximum compressive deflection c does not exceed 0.07 x T and under rotation, there is no uplift at any edge.