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采用非线性时程分析法,分析了减隔震桥梁和非减隔震桥梁的三维地震响应。通过对比减隔震桥梁在不同地震动激励下的动力响应,研究了减隔震桥梁承受近断层地震动的响应特性。通过对比减隔震和非减隔震桥梁纵向地震位移,研究了近断层地震动对铅销橡胶支座的减震性能的影响。研究结果表明:与普通地震动激励相比,在近断层长周期脉冲型地震动激励下,减隔震桥梁减震率由54.4%降低为18.3%,隔震支座的减震效果降低了;在近断层脉冲地震动作用下,减隔震桥梁梁体纵向位移为179.6mm,非减隔震桥梁为151.6mm,铅销橡胶支座增大了梁体的纵向位移,易造成相邻梁体的碰撞或落梁,因此,近断层地区桥梁不宜采用铅销橡胶支座隔震。
Nonlinear time-history analysis method is used to analyze the 3D seismic response of the seismically isolated bridge and non-seismically isolated bridge. By comparing the dynamic response of a seismically isolated bridge under different ground motions, the response of a seismically isolated bridge to near-fault ground motions is studied. The effect of near-fault ground motions on the damping performance of lead rubber bearings is studied by comparing the longitudinal seismic displacements of isolated and non-de-securable bridges. The results show that compared with ordinary ground motions, under the excitation of near-fault long-period impulsive ground motions, the damping of reduced seismic isolation bridges is reduced from 54.4% to 18.3%, and the seismic isolation effect of the isolated bearings is reduced. Under the action of near-fault pulse ground motion, the longitudinal displacement of the seismically isolated bridge beam is 179.6mm, the non-septal septal bridge is 151.6mm, the lead rubber bearing increases the longitudinal displacement of the beam body, Of the collision or falling off, therefore, the bridge near the fault should not be used lead rubber bearing isolation.