Seismic response of underground stations with friction pendulum bearings under horizontal and vertical ground motions

The previous earthquake surveys show that central columns are the weak parts in subway stations during the earthquakes. Reducing the seismic responses of central columns can ensure the safety of stations. Setting friction pendulum bearings (FPB) at the top of central columns may be a good strategy. In this paper, based on a subway station in Shanghai, the FPB is simulated detailly. The isolation effect and mechanism of the FPB is studied with the three-dimensional dynamic time history analysis method. The shearing force and bending moment of the station central columns and the inter-layer displacement of the station during the earthquake are analyzed. The vertical ground motion of different amplitudes is considered. It is found that during the earthquake, the FPB can effectively reduce the maximum shearing force of the central columns and slightly reduce the maximum bending moment. At the same time, it will not cause a significant increase in the inter-layer displacement. The vertical ground motion will reduce the isolation effect of the FPB, and the degree of the reduction increases with the increase of the vertical ground motion acceleration amplitude.

Automated summary

This paper simulates the FPB at a subway station in Shanghai and studies its isolation effect and mechanism. It is found that the FPB can reduce the shear force and bending moment of central columns during earthquakes, without significantly increasing inter-layer displacement. Vertical ground motion reduces the isolation effect of the FPB, with the reduction increasing with the acceleration amplitude of the vertical ground motion.