近断层地震作用下隔震梁桥地震响应参数影响研究

Influence of Seismic Response Parameters on Seismically-Isolated Girder Bridge Under Near-Fault Ground Motions

为了研究近断层地震作用下高阻尼橡胶(HDR)支座隔震梁桥在不同设计参数下的隔震效果,采用SAP 2000软件建立HDR支座隔震简支梁桥的等效单墩模型,选取典型近断层地震动记录作为输入地震波,分析桥墩高度、桥墩质量和等效隔震度对HDR支座隔震梁桥地震响应的影响。结果表明:HDR支座具有良好的隔震效果;桥墩越高,隔震后的墩顶位移峰值越大;HDR支座能有效降低低矮桥墩的近断层地震响应,但当墩高超过35 m或桥墩质量增大后,HDR支座的隔震效果就降低;等效隔震度越大,HDR支座的隔震效果越好;桥梁采用HDR支座进行隔震时,应保证等效隔震度大于3.0。

In order to study the seismic isolation effect of high damping rubber (HDR) bearings with different design parameters on girder bridge under the near-fault ground motions, the equivalent single-pier models of girder bridges with HDR bearings are established by using the SAP 2000 software. The records of typical near-fault ground motions are selected as seismic waves input to analyze the effects of pier height, pier mass and equivalent isolation degree on the seismic response of girder bridges with HDR bearings. The results show that the HDR bearings have a good isolation effect. The higher the pier, the greater the peak displacement at pier top after seismic isolation. HDR bearings can effectively reduce the seismic response of low piers to the near-fault ground motions. However, when the pier height exceeds 35 m or pier mass is increased, the isolation effect of the HDR bearings will decrease. The greater the equivalent isolation degree, the better the isolation effect of the HDR bearings. When the HDR bearings are applied to the seismic isolation design of bridges, the equivalent isolation degree should be set greater than 3.0.