耗能防撞装置在桥墩基底摇摆隔震中的性能研究

在桩基础桥墩基底摇摆隔震中,提出1种增加柔性耗能防撞装置设计方案.当罕遇地震发生时,桥墩在与基础分离处发生摇摆,与设计的防撞装置发生碰撞,延长了系统的撞击时间,使撞击力下降.利用多个钢绳柔性防撞圈同期作用的动态有限元方法,建立适当模型,并对防护围刚度分3种情况进行讨论.发现在撞击防撞装置的过程中,前期为部分防撞圈发挥作用,后期为全部防撞圈发挥作用,并且“同期作用历时”越短越好.分析结果表明,降低防撞构件的初始刚度,可延迟最大撞击时间,同时可减小最大的撞击压力.

Performance Study on Energy-consuming Anti-collision Devices in Pier Base Swing Isolation

In the swaying isolation of pier basement of pile foundation, a design scheme of collision-prevention device was put forward to increase flexible energy dissipation. When rare earthquake happens, a sway happens at the spot where the pier and the foundation separate from each other and it causes the pier to collide with the designed collision-prevention de- vice. Accordingly, the time of collision of the system is extended and the impact force is reduced. This paper employs the dynamic finite element method of flexible collision-prevention circle of multiple wire cables of simultaneous function to set up the appropriate model and discuss the stiffness of the collision-prevention circle under three situations. It is discovered that in the earlier stage of collision of the collision-prevention device, only part of the collision-prevention circle function, while in the latter stage all of that work, and the shorter ＂the length of time of simultaneous function＂ the better. The result of the numerical simulation shows that the decrease of the initial stiffness of the collision-prevention device is conducive to the delay of the time and to the decrease of pressure of the maximum collision.