强震下梁与桥台碰撞特性及防撞防落梁措施研究

Study on the impact characters of beam and abutment and the measures against collision and falling beam under strong earthquake

基于强震作用下梁与桥台相对位移及碰撞特性研究,结合桥台缩尺模型振动台试验,明确强震作用下桥台碰撞损伤规律,以及不同防撞防落梁装置对桥台结构动力响应的影响。研究表明:设置防撞垫片会使上部梁体与桥台间最大碰撞力削弱约50%;增加桥台隔震支座刚度,避开地震动卓越周期,可以在一定程度限制上部梁体位移,起到减隔震的效果。拉索式防落梁装置对上部梁体靠近桥台时的位移削弱达63.34%,有效保护桥台背墙;钢板式防落梁装置对桥梁结构上部梁体远离桥台侧的位移削弱达37.53%,有效防止发生碰撞作用和落梁现象;链式防落梁装置对上部梁体远离桥台位移削弱作用达93.98%,但同时也增加上部梁体靠近桥台背墙侧位移,能够有效防止落梁发生。

Based on study of relative displacement and impact characters of beam and abutment under strong earthquake, combining with the shaking table test of abutments scale model, to analyze the distribution rule of impact force between beam and abutment, and influence of different anti-impact and falling beam devices on the dynamic response of abutment. Researches show that: the maximum impact force between the beam and abutment is weakened by 50% due to the crash pad. Increasing the stiffness of seismic isolation bearings to avoid the earthquake predominant cycle, the displacement of upper beam can be limited to a certain extent. Cable type beam falling prevention devices weaken the upper beam displacement close to the abutment up to 63.34%, which protect the back wall of abutment effectively;Steel plate type beam falling prevention devices weaken upper beam displacement far from the abutment up to 37.53%, which prevent impact effect and beam falling phenomenon effectively. Chain beam falling prevention devices weaken upper beam displacement far from the abutment up to 93.98%, but also increases upper beam displacement close to the abutment, which prevent beam falling phenomenon effectively.