基于有限位移的中小跨径梁式桥抗震概念设计

以中小跨径梁式桥的抗震设计方法为研究对象,对汶川地区的中小跨径梁式桥进行了系统、全面的震害调查,总结了梁式桥的震害形式,采用统计分析的方法分析了各类构件的损伤情况,探明了汶川地震中梁式桥具有主梁移位多、支座、挡块震害多、桥墩震害少、主梁落梁少的显著特点;通过振动台试验和数值模拟方法,对梁式桥梁震害的机理进行了研究。结果表明,主梁与板式橡胶支座间的相对滑动起到隔震作用,减小了桥墩的地震内力响应,明显减少了桥墩震害,桥面连续协调了主梁位移,桥台约束了主梁的纵向位移是汶川地震中落梁少的主要原因。根据中小跨径梁式桥震害分析和机理研究,提出了利用主梁与支座间产生有限相对滑动、减小上部结构加速度响应,减少桥墩损伤的抗震设计概念。

Seismic concept design of small and medium span beam bridge based on finite displacement

Taking the seismic design method of small and medium span beam Bridges as the research object, a systematic and comprehensive earthquake damage survey of small and medium span beam Bridges in Wenchuan area is carried out, the earthquake damage forms of beam Bridges are summarized, and the damage conditions of various components are analyzed by statistical analysis. It is proved that the beam Bridges in Wenchuan earthquake have more main beam displacement, more earthquake damage of supports and stoppers, less earthquake damage of piers, and main beam fall Less prominent features; By means of shaking table test and numerical simulation, the mechanism of earthquake damage of beam bridge is studied. The results show that the relative sliding between the main beam and the plate rubber bearing plays a seismic isolating role, reduces the seismic internal force response of the pier, and significantly reduces the earthquake damage of the pier. The bridge floor continuously coordinates the displacement of the main beam, and the abutment constrains the longitudinal displacement of the main beam, which is the main reason for the few falling beams in the Wenchuan earthquake. Based on the seismic damage analysis and mechanism research of small and medium span beam bridge, the seismic design concept of using the limited relative sliding between the main beam and the support to reduce the acceleration response of the superstructure and reduce the pier damage is proposed.