超长联连续梁桥考虑行波效应的减震优化研究

Research on seismic optimization of super-long continuous bridge considering travelling wave effects

为了提高超长联连续梁桥的抗震性能,以某跨径布置为(60+11×86+60)m的预应力连续梁桥为工程背景,基于SAP2000建立有限元分析模型,采用绝对位移法模拟行波效应,对比研究了行波效应对超长联连续梁桥地震响应的影响,重点研究了超长联连续梁桥考虑行波效应的减震优化措施。研究表明:行波效应对墩底内力、墩顶位移、支座滑移和剪力,以及伸缩缝两端相对位移(碰撞效应)均存在不同程度的影响;超长联连续梁桥若只设置一个固定墩,会导致固定墩因进入严重的塑性变形状态而破坏,采用摩擦摆隔震支座可以显著优化固定墩地震响应,但无法改变伸缩缝处的碰撞效应;在摩擦摆支座的基础上加设黏滞阻尼器可大幅度减小伸缩缝两端相对位移,甚至可以消除碰撞现象。

In order to improve the seismic performance of super-long continuous girder bridges,a pre-stressed continuous girder bridge with a span arrangement of(60+11×86+60)m is used as the engineering background,a finite element analysis model is established based by SAP2000,the absolute displacement method is used to simulate the travelling wave effects,the effect of travelling wave effects on the seismic response of super-long continuous girder bridges is studied in comparison,and the focus is on the seismic optimisation measures for super-long continuous girder bridges considering the travelling wave effects.The study shows that the travelling wave effects has different degrees of influence on the internal force at the bottom of the pier,the displacement at the top of the pier,the slip and shear of the bearing,and the relative displacement at the both ends of the expansion joints(collision effect);if only one fixed pier is installed in the super-long continuous girder bridge,it will be damaged due to enter a state of severe plastic deformation.Using the friction pendulum bearings can significantly optimise the seismic response of the fixed piers,but cannot change the collision effect at the expansion joints;the addition of viscous dampers on the basis of friction pendulum bearings can substantially reduce the relative displacement of the both ends of the expansion joints and even eliminate the phenomenon of collision.