Abstract： The bi-directional coupled interaction of FPS under two horizonta1 orthogonal directional excitations was investigated. Based on a nonlinear numerical model of a typical continuous long span bridge isolated with FPS, the seismic responses taking into account or ignoring the bi-directional coupled interaction of bearing restoring force were compared at different levels of parameters such as pier height, yield strength and bearing radius. The results show that the bi-directional coupled interaction has considerable effects on the seismic responses of the isolated bridge. If these effects are ignored, the peak bearing displacements will be greatly underestimated, which is crucial for isolated bridges from the design point of view.
2011, Vol. 30 
