板式橡胶支座桥梁地震位移控制方法

Displacement Control Method for Continuous Bridges on Laminated Rubber Bearings Under Earthquake Excitation

为了克服中国采用板式橡胶支座的中小跨径桥梁易发生梁体移位震害的不足,合理控制梁体地震位移,以一典型板式橡胶支座连续梁桥为研究背景,采用SAP2000有限元程序,考虑板式橡胶支座的滑动效应,建立了桥梁结构空间动力计算模型,进行了非线性时程地震反应分析,研究了地震动特性对梁体地震位移的影响,探讨了板式橡胶支座桥梁存在的问题,提出了将一联梁桥中某中间桥墩的板式橡胶支座改为铅芯橡胶支座的地震位移控制方法。结果表明:该方法能有效控制梁体地震位移,虽在一定程度上增大了设置铅芯橡胶支座桥墩的地震反应,但与可能的落梁震害相比,桥墩发生有限损伤是可接受的。

To overcome the deficiency of small and medium span girder bridges on laminated rubber bearings in serious girder displacement during earthquake excitation in China, and to control the girder seismic displacement to a reasonable level, with a typical continuous bridge on laminated rubber bearings as the object, the finite element program SAP2000 was used to establish the spatial finite element calculating model of the bridge with consideration of the effect of bearing sliding, and the seismic response analysis of bridge structure using nonlinear time history method was carried out. The influence of ground motion on girder seismic displacement was studied, the possible defects of continuous bridge on laminated rubber bearings under longitudinal earthquake excitation were discussed, and a new method for controlling girder seismic displacement was proposed, in which laminated rubber bearings at an intermediate pier in a continuous bridge were replaced by lead-rubber bearings. The results show that the new method is effective in controlling girder seismic displacement; since the seismic effect of the pier, at which lead-rubber bearings are installed instead of laminated rubber bearings, is increased to some extent, the possibility of bridge collapse becomes smaller and the damage to piers is more acceptable.