桥台支座布置方式对连续梁桥地震反应的影响

Effects of abutment′s bearing distribution on seismic response of continuous bridges

为了避免桥台的地震破坏,提出一种新型桥台支座布置方式,通过双向滑动支座、弹塑性挡块和拉压连接装置的联合作用来工作.以2座连续梁桥为例,通过新型桥台支座布置方式和传统桥台支座布置方式的对比研究,分析了挡块屈服力、桥台约束刚度对桥梁横向地震反应的影响.结果表明:对于传统桥台支座布置方式,桥台承受的地震力随着地震强度的增大而增加,存在地震破坏风险;对于新型桥台支座布置方式,可以通过调节挡块横向屈服力来控制桥台地震力,既可使桥台分担一部分结构地震惯性力,又可避免桥台破坏.进行抗震设计时,可以根据具体的桥梁和对应的地震动输入,选择合适的桥台挡块横向屈服力,以使整座桥梁的地震反应达到最优状态.

A abutment′s bearing distribution was advanced to avoid abutment′s earthquake effects,which united the two-way sliding bearing,the elastic-plastic fender and the tension-compression link to work.Taking two continuous bridges as an example,the abutment′s bearing distribution was analyzed compared with the traditional abutment′s bearing distribution,which could reflect the fender′s yielding force and the abutment restriction stiffness′influence on the bridges′lateral seismic response.Results show that as for the traditional abutment′s bearing distribution,the abutment′s earthquake force would increase along with the earthquake′s increment.Therefore,the abutment would have the risk of damage in the earthquake.As for the new abutment′s bearing distribution,the fender′s lateral yielding force can be adjusted to control the abutment′s earthquake force,therefore,the abutment not only shares a part of superstructure′s earthquake inertia force,but also avoids itself earthquake damage.As for the seismic design of continuous bridge,based on the bridge structure and the earthquake input,the fender′s reasonable yielding force can be selected to make the whole structure′s seismic response best.