Annular fiber-reinforced elastomeric bearings for seismic isolation of lightweight structures

Abstract

The conventional laminated elastomeric bearing isolators, as a mature technology, have found significant application in earthquake protection of civil structures, which are typically large in size, heavy, and expensive in cost. The technology is not as effective in the seismic isolation of lightweight structures due to the challenges in providing effective period-shift while accommodating large isolator displacement demands. Further horizontal flexibility may yet be required in the elastomeric isolators concerning the Seismic isolation of lightweight structures. A novel hollow circular (HC, also called the annular) type of fiber-reinforced elastomeric isolators (FREIs) is introduced and examined in this study. To demonstrate the validity of the concept, the dynamic response characteristics of two similar full-scale HC-FREIs were evaluated experimentally and compared with those of a corresponding solid circular (SC)-FREI as the control specimen. The response parameters, performance limit states, and failure modes of the two isolator types were evaluated and compared in detail. In addition, the performance of the two isolator types in the base isolation of a lightweight structure was investigated. Given the significantly increased horizontal flexibility and superior damping properties, the unbonded HC-FREIs offer a feasible solution for the effective earthquake mitigation of many lightweight structures. Additionally, the comparatively lower volume of materials and the lighter weight of the isolator provide economic advantages for HC-FREIs over their SC-FREI counterparts.