Seismic Base Isolation of Steel Frame Structure by Hollow Rubber Bearings

Abstract

Effectiveness of rubber bearing in providing seismic base isolation depends very much on the lateral stiffness of these rubber bearing. The competency is increased by lowering the bearing’s horizontal stiffness. This can be easily achieved by either reducing its diameter or increasing its height without compromising the rollout and buckling stability of the rubber bearing. This paper presents shake table testing of fixed base steel frame structure (FBS) in comparison to two identical base-isolated models with solid rubber bearings (BISRB) and hollow rubber bearings (BIHRB), respectively. It is noted the optimum diameter reduction recommended will be 40%. Generally, the seismic performance of BIHRB is superior to both FBS and BISRB, by producing lower floor accelerations and inter-story drifts. Key Words: seismic, base isolation, rubber bearing, steel frame.