1. Elastomeric bearings must not be placed one behind the other along the longitudinal axis of the girder on a single line of support under any circumstances.

2. Bearings of different plan size must not be installed next to each other (on the same pier) under the same girder/span.

Different plan area will lead to different value of 'δ' for given values of H, h and G as under:

3. The contact surface between the bearing and the bed block must be horizontal to avoid tangential force due to gravity coming on to the bearing (maximum tolerance 0.2%.