Bearing Seismic Activity: Mechanical Characterization of Laminated Rubber Bearings

Seismic isolation using rubber bearings in bridges and buildings have proven to be a very effective passive method for reducing earthquake-induced forces. The basic concept is not new - they've been used for many decades in large pads, to support massive bridge girders, while permitting their thermal expansion. Laminated Rubber Bearings (LRB’s) have been used for earthquake protection in multiple units to support entire buildings while yielding laterally to earthquake ground shaking. Seismic base isolation is one of the most popular means of protecting a structure against earthquake forces.

This chapter discusses an experimental scheme used to characterize mechanical behavior and subsequently develop a mathematical model representing the characteristic behavior of the bearings. It is difficult to measure the local internal responses of a rubber bearing in a shake-table test. Therefore, it will be an indispensable tool to use for analysis and design of laminated rubber bearings. Incorporation of damping, softening property, and effect of temperature change for lead and high-damping rubber bearings remains to be investigated in future research.