地震作用下斜交简支梁桥桥面旋转反应的参数分析

摘要

地震引起的斜交简支梁桥桥面面内旋转不仅增大了梁体的纵、横向位移，而且增加了梁体与边界碰撞的几率。为研究地震作用下斜交简支梁桥桥面的旋转反应，利用 OpenSees 地震仿真模拟平台，建立考虑梁体与桥台间纵向碰撞、梁体与挡块间横向碰撞效应的斜交简支梁桥简化动力计算模型，分析梁体与桥台间纵向碰撞刚度、伸缩缝间隙、梁体与挡块间碰撞刚度、初始间隙、挡块力学特性等对斜交简支梁桥桥面旋转的影响。结果表明：纵向碰撞刚度、伸缩缝间隙、梁体与挡块间初始间隙对斜交简支梁桥桥面转角的影响较大，而横向碰撞刚度对桥面转角的影响相对较小；梁两端锐角区设置纵向垫块对减小桥面转角和纵向位移有较好的效果；设置弹塑性挡块能有效控制桥面的震致转动，减轻挡块的横向受力。%The deck's inplane rotation caused by seismic responses of simply-supported skewed girder bridges (SSGB)not only increases the longitudinal and transverse displacements of deck but also increases the probability of pounding between girder and boundary.In order to investigate the deck's seismic inplane rotation response of SSGB,a simplified dynamic calculation model considering the effect of pounding between girder and boundary in SSGB was developed by using OpenSees earthquake simulation platform.The effects of longitudinal pounding stiffness,initial gap at expansion joint,transverse pounding stiffness,initial gap between girder and shear keys and mechanical characteristics of shear keys on the deck's seismic inplane rotation of SSGB were analyzed.The results indicated that the longitudinal pounding stiffness,the initial gap at expansion joint and the transverse initial gap have significant effect on the deck's seismic rotation of SSGB,while the transverse pounding stiffness has relatively unremarkable effect on the deck's seismic rotation of SSGB;setting pads in acute angle zones at girders'both ends in SSGB can reduce seismic rotation angle and longitudinal displacement of the girder;using elastic-plastic shear keys can control effectively the seismic inplane rotation angle of deck and mitigate the transverse force of shear keys in SSGB.