结构参数对高低墩刚构连续梁桥体系地震响应的影响

Influence of structural parameters on the seismic response of rigid-frame continuous girder bridges with high and low piers

地震作用下,相邻主梁间的碰撞会改变桥台-引桥-刚构连续梁桥结构体系的动力响应。为了探究主桥结构形式、墩高、引桥跨数和伸缩缝间距等结构参数对伸缩缝处碰撞效应和桥梁结构地震响应的影响,以某实际桥梁为背景,考虑碰撞能量耗散、桩土相互作用、桥台与台后填土相互作用以及支座和桥墩的非线性行为,采用CSIBridge建立桥台-引桥-刚构连续梁桥结构体系的有限元模型进行碰撞弹塑性动力分析。研究结果表明:不同主桥结构形式的主桥墩受力区别较大,相邻主桥墩高差较大时,选择连续梁桥结构体系更加合理。墩高增加使主引桥间动力差异增大,碰撞效应更加显著,仅对刚构墩受力影响较大。引桥跨数增多和伸缩缝间距增大分别使伸缩缝处碰撞效应增大和减小,碰撞抑制作用的增强和减弱也使得刚构墩内力和变形分别减小和增大,但对于其他桥墩基本无影响。

Under earthquake action,the pounding between adjacent main beams can change the dynamic response of an abutment-approach bridge-rigid frame continuous girder bridge system.To explore the influence of structural parameters(structural form of main bridge,pier height,span number of approach bridge,expansion joint spacing,etc.)on the pounding effect at expansion joints and seismic response of bridge structure,we considered an actual prototype bridge as a research object.We considered the dissipation of pounding energy,the interaction between pile and soil,and the interaction between abutment and backfill behind abutment and established the nonlinear behavior of bearing and pier,a finite-element model of the abutment-approach bridge-rigid frame continuous girder bridge structure system was established using CSiBridge,and elastic-plastic dynamic analysis was carried out.The analysis results reveal that the stress of the main pier varies with the different structural forms of the main bridge,and the stress of the continuous girder bridge becomes more reasonable when the height difference between adjacent main piers increases.With the increase in pier height,the dynamic difference between the main approach bridges increases,and the pounding effect becomes more significant.The increased number of spans of the approach bridge and the increase in the spacing between expansion joints cause the pounding effect at the expansion joints to increase and decrease,respectively.The enhancement and weakening of the pounding suppression effect also cause the decrease and increase in the internal force and deformation of rigid frame piers,respectively,but have a negligible effect on other piers.