活动支座摩擦作用对高铁简支梁桥地震响应的影响

Influence of Movable Support Friction on Seismic Response of High-speed Railway Simple-supported Beam Bridge

摘要:

选用高速铁路10×32 m简支梁桥为工程背景，建立考虑轨道约束效应的全桥弹塑性动力分析模型，并以桥墩侧移角、墩底截面延性率、道床板与主梁摩擦单元的屈服位移、道床板轴力、钢轨轴力为评价指标，研究了罕遇地震作用下活动支座摩擦作用对考虑轨道约束效应的高速铁路简支梁桥地震响应的影响。结果表明：活动支座摩擦作用对简支梁桥下部结构及轨道系统的影响较小，均在10%之内；随着活动支座摩擦系数的增加，其支座位移、桥墩侧移角、墩底截面延性率均减小，道床板与主梁摩擦单元的屈服位移、道床板轴力和轨道轴力均增加；总体上，活动支座摩擦作用的增加对简支梁桥下部结构地震反应有利，对轨道系统不利。

Abstract:

Selecting a 10×32 m simple-supported girder bridge of high-speed railway as the engineering background, the full-bridge elasto-plastic dynamic analysis model considering the restraint effect of track is established. The lateral displacement angle of the pier, the ductility of the pier bottom section, the yield displacement of the friction unit between the track bed plate and the main beam, the axial force of the track bed plate and the axial force of the steel track are used as the evaluation indexes to study the influence of the friction effect of movable supports under the rare earthquakes on the seismic response of simple-supported girder bridges of high-speed railways considering the track constraint effect. The results show that the frictional effect of the movable supports on the substructure of the simple-supported girder bridge and the track system is relatively small, both within 10%. With the increase of the friction coefficient of the movable supports, the support displacement, the lateral displacement angle of the pier and the ductility of the pier bottom section all decrease, and the yield displacement of the friction unit between the track bed plate and the main beam, the axial force of the track bed plate and the axial force of the track all increase. In general, the increase in the frictional effect of the movable supports is beneficial to the seismic response of the substructure of the simple-supported girder bridge, but unfavorable to the track system.