近断层地震特性对隔震曲线连续梁桥地震响应的影响

为研究近断层地震动对曲线连续梁桥地震响应及碰撞效应的影响,采用非线性时程分析法,分别研究脉冲效应、上盘效应及方向性效应对某三跨曲线连续梁桥支座位移、桥墩内力及邻梁间碰撞力的影响;通过支座隔震率的对比分析,探究不同类型近断层地震动下地震响应产生差异的原因。研究结果表明:脉冲效应、上盘效应和方向性效应均会增大曲线连续梁桥地震响应,脉冲效应的影响尤为显著;脉冲效应和方向性效应削弱了高阻尼橡胶支座的隔震特性,而上盘效应对桥梁响应的影响仅与上盘地震动自身特性有关;综合来看,脉冲效应对曲线梁碰撞响应影响最明显,上盘效应影响不大。

Influence of near-fault ground motion characteristics on the seismicresponse of isolated continuous curved girder bridges

To study the seismic response and pounding effect of curved continuous girder bridges under near-fault ground motions,the nonlinear time history analysis method was used to analyze the influence of velocity pulse effect,hanging wall effect,and directivity effect on the bearing displacement,the internal force of pier,and the pounding force between girders of a three-span continuous curved girder bridge.Through a comparative analysis of bearing isolation ratio,the reasons for the difference between seismic responses of the bridge under different types of near-fault ground motions were explored.The results showed that the impulse effect,the hanging wall effect,and the directional effect will all increase the seismic response of the curved continuous beam bridge,especially the impulse effect.The impulse effect and directivity effect weaken the seismic isolation performance of the high-damping rubber bearing,while the influence of hanging wall effect on the bridge response is only related to the characteristics of hanging wall ground motion.Overall,the impulse effect has the most obvious impact on the pounding effect of the curved girder,and the hanging wall effect can be neglected.