Experimental study on hysteretic performance of a new type of friction pendulum isolation bearing

A new seismic isolation bearing design is proposed by combining the Double Friction Pendulum Bearing (DFPB) with the Double U-shaped Damper, resulting in the Double Friction Pendulum Bearing with Double U-shaped Damper (DU-DFPB). In this paper delineates the structural design and working principle of the DU-DFPB, whilst concomitantly conducting experimental studies of the hysteresis performance of DFPB specimens under varying working conditions. The experimental study also encompasses the hysteresis performance of three DU-DFPB specimens, and a comparative and analytical approach is adopted to assess the hysteresis performance of the DFPB specimen and the three DU-DFPB specimens. The results reveal that the hysteresis curve of the DFPB exhibits bilinear characteristics, and the increase of horizontal displacement, the enhancement of vertical force and the increase of friction coefficient can effectively enhance its energy dissipation performance; while the hysteresis curve of the DU-DFPB exhibits a pike shape, which significantly enhances the load carrying capacity and stiffness of the support. The outer damper can still maintain its function though the inner damper breaks, thereby further enhancing the energy dissipation efficiency of the friction pendulum bearing.