Laminated Rubber Bearing

1. Principle

GTR Laminated Rubber Bearing is a vulcanized elastomeric rubber block reinforced by steel layers. These bearings are specially designed to support vertical loads, accommodate movement in any direction, while also allowing minor rotations about any axes.

The steel layers inside can essentially increase the vertical load capacity and transversal strength. The rotations about any axes and horizontal movements can be permitted by the deformation of inner rubber layers.

GTR Laminated Rubber Bearings can be fabricated and designed in accordance with EN1337-3, BS5400 or AASHTO LRFD bridge construction specifications, as appropriate.

2. Structure

GTR Laminated Rubber Bearings are made from elastomers which encapsulate inner reinforcing steel plates. These two materials bonded together by vulcanization, means high pressure and high temperature. Reinforcing steel plates can provide higher load capacity and confine the rubber layers when horizontal deformation is taking place. Rubber layers provide enough elasticity, which can absorb the impact from the external environment, and also ensure the movements and rotations from superstructure appropriately.

It may be provided with a sliding surface to accommodate large movements and also can have one or two horizontal movement restrainers.

3. Application and Advantage

GTR Laminated Rubber Bearings are mainly used in bridges with lower load, small permissible concrete pressure and separated structures.

These bearings of simple construction and lightweight are easy to install maintenance free, economical and have high durability.

4. Types

GTR Laminated Rubber Bearings are generally classified into:

GTRFLaminated rubber bearings with lower displacement capacity. The shape of bearing can be rectangular or circular. The horizontal displacement can only be absorbed by the shear deformation of rubber layers.

GTRM —Laminated rubber bearings with larger movement capacity. The shape of bearing can be rectangular or circular. The horizontal displacement can be absorbed by PTFE sliding surface and mating SS plate.

5. Raw Materials

These bearings can be made from Natural Rubber, Neoprene or natural rubber covered by neoprene to increase the aging resistance.

l Elastomer used in the bearing shall satisfy the following requirements:

l Reinforcing steel plates and SS backing plate are made of ASTM A709/A709M Grade 36 or higher quality.

l PTFE surface are made from virgin PTFE resin or blended with fiber (glass or carbon).

l Stainless steel conform to the requirements of ASTM A240/A240M, Type 304 with a minimum thickness of 20 gage