Motion Analysis of Pendulum-Type Isolation Systems During Earthquakes: Dynamic Test and Response Analysis on a Three Story Steel Frame Model Supported by Four Friction Pendulum Bearings

After the Hanshin-Awaji Earthquake Disaster, the number of earthquake isolated buildings is increasing. Most of the base isolated buildings or structures are built on laminated rubber bearings in order to give them certain natural periods. This situation, however, also encourages structural engineers to research and develop nonrubber-type isolation systems such as linear motion bearing isolators and friction pendulum systems. It is considered that the nonrubber-type isolation systems can be applied to important industrial facilities, such as LNG tanks, boiler facilities and so on to refine their seismic reliabilities. In the device of the nonrubber-type isolation systems, the device which applied the sliding is especially noticed. However, when using nonrubber-type isolation systems with sliding in the open air circumstances, long term durability of the systems must be taken into account and it may be very difficult to maintain the friction coefficient of the system. In this study, the dynamic motion analysis and the experimental tests on the isolated structure mounted on four Friction Pendulum Bearing (FPB) Systems were carried out to investigate the performance of isolation due to the rotational motion which might be induced by the friction force difference in FPB system.