Design of Base Isolation System for Buildings

Abstract

Seismic base isolation is one of the most widely implemented and accepted seismic protection systems and is a relatively recent and evolving technology. The most common isolation system used is Laminated Lead Rubber Bearings (LLRB). They combine the function of isolation and energy dissipation in a single compact unit, giving structural support, horizontal flexibility, damping, and a re-centering force in a single unit. The force deformation behavior of LLRB is modeled as bilinear system with viscous damping. In this paper, a comprehensive design of LLRB is presented. Accurate evaluation of the structural properties and precise modeling of isolation devices are of utmost importance in predicting the response of the structure during the earthquakes. Base isolation has now been used in numerous buildings in countries like Italy, Japan, New Zealand, and USA. Base isolation is also useful for retrofitting of important buildings (like hospitals and historic buildings).