Seismic performance evaluation of bridge pier with friction pendulum isolation system

After the Great Hanshin Kobe Earthquake (1995), extensive effort for improving the seismic performance of bridges in the Japanese engineering community have been carried out. Although, isolation system has become effective to ensure the seismic resilience of bridge structures, high axial load and large displacements under strong ground motions are not well understood; moreover, during Tohoku Earthquake (2011) and Kumamoto Earthquake (2016), some damages of laminated rubber bearing were observed. Undoubtedly, it is necessary to continue developing the isolation systems by exploring new concepts. In this study, seismic performance evaluation of a novel system to isolate the superstructure by forming a concave sliding surface on the top of the concrete bridge pier; is experimentally conducted. Any seismic devices are not included for lengthening the system to a longer natural period, and based on the principle of pendulum the seismic energy can be dissipated through the frictional force. Proposed Friction Pendulum Isolation System (FPIS) possess re-centering capability while sliding toward the initial position, and large displacement can be enhanced. The results exhibited shear force-displacement relationship with a smooth behavior in the longitudinal direction; furthermore, the longitudinal and transverse direction depicted an appealing circular displacement orbit.