Influence of thickness of individual elastomer layers (first shape factor) on the response of unbonded fiber-reinforced elastomeric bearings

The objective of this paper is to study the influence of thickness of individual elastomer layers (first shape factor) on the vertical and horizontal responses of fiber reinforced elastomeric bearings that are not bonded or mechanically fastened to their top and bottom supports. By definition, the first shape factor, S 1 , is the ratio of the plan area to the perimeter stress-free area of a single elastomer layer within the bearing. Results of a comprehensive 2D-finite element study on a large group of bearings with different shape factors of 10, 15, 20, 30, and 40 suggest that the shape factor S 1 is a critical parameter in controlling both the vertical compression modulus of the bearing and the level of stress in the fiber-reinforcing layers. Furthermore, the secant horizontal stiffness and the stress demand in the bearing elastomer material are to a limited extent influenced by the parameter S 1 .