LRB and FPS Seismic Isolators: A Comparative Review

Seismic Isolation is one of the easiest solutions to reduce the damage caused by earthquakes on structures. This method which is classified as a passive structure control system, by decreasing the base acceleration and increasing the base period of building, helps with significantly reducing the devastating effects of earthquakes on structures and objects and people inside buildings. Decades after design, construction and deployment of the first seismic isolator, various types of isolators and their feasibility in different situations and structures have been examined. Nonetheless, any comprehensive comparison between different types of isolators has not been done yet. Sliding systems are the simplest and most primitive types of isolators made. However, it is the rubber bearings that have been used more widely in a large variety of buildings. Each type of isolators has their own particular strengths and weaknesses that become visible in structural or environmental conditions. Among the rubber seismic isolators, lead-rubber bearings and among the sliding isolators, friction-pendulum isolators have the best performance in different structures and became the most widely used seismic isolators. In this article, firstly, the fundamentals of seismic isolation and an introduction to the variety of isolators is mentioned, then mechanical properties and the equations of motion of two types of seismic isolators: Lead-Rubber Bearings and Friction-Pendulum Systems are examined and their strengths and weaknesses are compared. Then the results of previous researches in comparison of two types of seismic isolators to be implemented in bridges and buildings are summarized and in the end, findings are presented.

LRB and FPS Seismic Isolators: A Comparative Review Keywords:

1. Introduction