Torsionally Seismic Behavior of Triple Concave Friction Pendulum Bearing

Abstract

In this paper, attempts are made to investigate the responses of torsionally coupling base-isolated structure supported on Triple Concave Friction pendulum bearing (TFP) subjected to near field ground motions. Nonlinear dynamic analyses are conducted to study the effects of essential parameters such as superstructure and isolation system eccentricity, and the uncoupled torsional to lateral frequency ratio of superstructure on seismic responses of TFP isolated structures. Further, the responses of base-isolated structure using TFP are compared with the same base-isolated structure using friction pendulum system (FPS) as well as double concave friction pendulum (DCFP). Results indicate that TFP isolated structure significantly outperforms other types of friction bearings. Moreover, increasing effective period causes TFP isolated structures to behave better than the others in reducing torsional responses of structure. It is concluded that effectiveness of TFP isolators in respect to others bearings is negligible on seismic responses of structures through increasing effective damping.