Hole and lead plug effect on fiber reinforced elastomeric isolator for seismic isolation

This paper presents an investigation of the effect of hole and lead plug in FREI (fiber reinforced elastomeric isolator) where the reinforcing element-normally steel plates-are replaced by a fiber reinforcement. The FREI, in contrast to the SREI (steel reinforced elastomeric isolator), which is assumed to be rigid both in extension and flexure, is assumed to be flexible in extension, but completely lacking flexural rigidity. In accordance with the proposed theory, the FREI is designed and fabricated for evaluation of the performance on seismic isolation. Experiments are carried out to evaluate and compare the performances of fiber reinforcement with steel reinforcement, and the hole and lead plug effect on effective stiffness and effective damping of carbon FREI. From the experiments, the performance of the FREI is superior to that of the SREI in view of horizontal stiffness and vertical stiffness of the isolator. It has been shown that hole and lead plug do not make much differences with FREI without hole and lead plug. Therefore, it is possible to produce an FREI that matches the behavior of an SREI. Consequently, the FREI without hole and lead plug could replace the conventional SREI for seismic isolation with low-cost manufacturing and lightweight installation. (C) 2003 Published by Elsevier B.V.