高速铁路钢混连续梁桥弹性约束体系抗震性能研究

Study on Seismic Performance of Elastic Restraint System of High Speed Railway Steel-concrete Continuous Girder Bridge

以一座高速铁路大跨度钢混连续梁桥为工程背景,介绍了弹性约束体系及设计参数取值方法,从动力特性、桥墩剪力、墩顶位移等方面对比分析了弹性约束体系、连续约束体系的地震响应,探究弹性约束体系纵向抗震性能。结果表明:与连续约束体系相比,弹性约束体系显著延长了桥梁结构自振周期,且多个主墩协同受力;弹性约束体系有效减小了桥墩纵向剪力和墩顶水平位移,设计、罕遇地震工况下桥墩纵向剪力减震率分别为61.26%、40.56%;罕遇地震工况下,弹性约束多功能支座位移达到弹性位移设计值,纵向水平力由纵向限位装置、弹性约束装置共同承担。弹性约束体系具有良好的纵向减震性能,设计地震、罕遇地震工况下桥墩纵向剪力平均减震率分别为60%、43%。

Taking a long-span steel-concrete continuous girder bridge of high speed railway as engineering background, the elastic restraint system and the value selection method were introduced, the seismic response of elastic restraint and continuous restraint system were compared from the aspects of dynamic characteristics, pier shear and pier top displacement, the longitudinal seismic performance of elastic restraint system was explored. The results show that compared with the conventional continuous restraint, the elastic restraint system significantly prolongs the natural vibration period of bridge structure, and the multi main piers bear the force cooperatively. The elastic restraint system effectively reduces the longitudinal shear force of the pier and the horizontal displacement of the pier top. The seismic reduction rates of the longitudinal shear force of the pier under the design and rare earthquake conditions are 61.26%and 40.56% respectively. Under the condition of rare earthquake, the displacement of elastic restraint multifunctional bearing reaches the design value of elastic displacement, and the longitudinal horizontal force is jointly borne by the longitudinal limit device and elastic restraint device. The elastic restraint system has good longitudinal seismic reduction performance, the average seismic reduction rates of pier longitudinal shear under design earthquake and rare earthquake conditions are 60% and 43% respectively.