Seismic displacement response analysis of Friction Pendulum Bearing under friction coupling and collision effects

Friction Pendulum Bearing (FPB) with shearing keys will exhibit friction-coupling effect and collision phenomenon subjected to horizontal orthogonal ground motions. This paper establishes a numerical analysis model of FPB with four shear keys and viscous damping, considering the impact of the friction coupling effect and collision between the FPB and the shear keys on its displacement response. The influence of parameters of FPB on seismic displacement response with considering collision effect under horizontal orthogonal ground motions was studied. The results suggest that adjustments in damping and equivalent stiffness exclusively impact the amplitude of the displacement response, maintaining the response waveform. Conversely, variations in friction significantly alter the response waveform, as friction induces changes in the natural frequency of FPB. A heightened collision impact is noted with reduced spring stiffness. The displacement response is particularly amplified when the collision occurs at the vicinity of peak displacement in the time-history response of FPB. When the restoring stiffness and Peak Ground Acceleration (PGA) are low, the friction coupling effect significantly reduces the amplification of displacement response caused by collision effects. Viscous damping can considerably reduce the impact of collisions on the peak displacement of FPB and prevent the collision effects from noticeably amplifying or diminishing the peak displacement of FPB.