采用摩擦摆支座的超大跨连续梁桥隔震效果

Seismic Isolation Effect on Super Long Span Continuous Beam Bridge Based on Friction Pendulum Bearings

为了研究超大跨连续梁桥采用摩擦摆支座的隔震效果,以某主跨为240 m的七跨钢-混凝土连续梁桥为工程背景,建立桩土相互作用动力分析模型,采用非线性连接单元模拟盆式滑动支座及摩擦摆支座的非线性受力性能.非线性地震响应分析结果表明:采用传统抗震体系时,超大跨连续梁桥的固定墩及其桩基础的内力需求非常大;采用摩擦摆支座的隔震体系可以减少固定墩及其桩基础内力约40%,并显著改善其他桥墩的地震力分配.摩擦摆支座对超大跨连续梁桥的减震机理主要体现为:延长结构自振周期、减小固定墩有效振动质量、改变地震力传递途径、增强附属装置耗能,从而显著地改善了超大跨连续梁桥的地震响应.

To study the seismic isolation effect of friction pendulum bearing to super long span continuous beam bridge, a 7-spancontinuous beam bridge with main span of 240 m is taken as research background.The finite element dynamic model is established,and the soil-pile-interaction effect and nonlinear properties of bearing are considered.The nonlinear seismic analysis result shows thatthe seismic responses of the fixed pier and piles in anti-seismic system are very huge. However, the seismic responses can be de-creased nearly 40%in friction pendulum bearing isolation system.Mechanisms of the seismic isolation system include primarily fol-lowing four parts：extending period, minimizing the effective mass of fixed piers, adjusting the force transmission route and increasingenergy dissipation.Therefore,the seismic response of super long span continuous beam bridge is improved remarkably.