Effects of spatial variable ground motions on the seismic response of isolated bridge with LRB

In the paper the influence of spatially ground motion on the longitudinal seismic response of isolated bridge with LRB(Lead Rubber Bearing) is presented. Nonlinear element models are created for the bridge and nonlinear time history analysis is conducted. First, artificial earthquake motion being compatible with code response spectrum is generated using spectral representation method. Structural vibration mitigation effects are compared each other under seven working conditions of excitation ,which uniform excitation, non-uniform excitation considering only wave passage effect, only incoherence effect, non-uniform excitation considering both the wave passage effect and incoherence effect, and non-uniform excitation considering wave passage effect, incoherence effect and local site effect are included. For the medium and small span bridge isolated with LRB, the wave passage effect and incoherent effect are not significant, and can be ignored for simplicity. But the local site effect has significant effect on the seismic response of the isolated bridge, and must be considered in the seismic response analysis.