Effect of Curvature and Seismic Excitation Characteristics on the Seismic Response of Seismically Isolated Curved Continuous Bridge

摘要

According to the characteristic of seismically isolated curved beam bridge design, the bidirectional nonlinear behavior of lead rubber bearing is taken into account by using two orthogonal nonlinear spring element. Reasonable strong seismic motion records are selected. Considering the effect of characteristic of curved beam bridge, the FEA software is used to do the nonlinear time history analyses for the curved beam bridges with and without lead rubber bearing under bidirectional seismic motions. The study results are obtained as follow: 1) vibration models of curved beam bridge are correlative with the connection between pier and beam and the natural period of seismic isolated curved beam bridge can not be affected by the radius of curvature; 2) the principal natural period of the seismically isolated curved beam bridge can be prolonged to avoid the predominant period of seismic motions. Therefore, the seismic response of the seismically isolated curved bridge can be reduced; 3) the seismic response of structure is greatly discrepant under different seismic motions. Especially, when the duration of seismic motion prolongs or the natural period of seismically isolated bridge approaches to the predominant period of seismic motion, the seismic response of structure can be enhanced.