刚性基础上摇晃桥柱系统地震反应研究

运用刚体摇晃减震概念建立摇晃桥柱系统(Rocking Pier System,RPS)的动力分析模式,并采用El Centro地震波作为输入,对RPS有无配置预应力钢筋、预应力钢筋有无施加预应力、预应力钢筋面积多少、不同桥柱振动周期及不同地震强度等进行时程分析.研究结果显示,桥柱摇晃碰撞基础瞬间,柱底虽会产生剪力峰值,但相较于传统桥柱系统(Conventional Pier System,CPS)的最大柱底剪力而言,该剪力峰值相对较小,此现象有助于避免地震时桥柱受损.且借助调整预应力钢筋面积及初始预应力可设定启动RPS晃动的地震强度,这样可避免小地震下桥柱晃动影响桥梁运输功能,并且在大震摇晃下桥梁保持弹性全无损伤.

Seismic Response of Rocking Pier System on Rigid Foundation

This paper proposed a theoretic model to analyze the dynamic behavior of a bridge by applying the concept of rocking pier system (RPS) . Numerical analysis was proceeded to investigate the performance of the RPS under various circumstance such as with or without tendons, with slack or post-tensioned tendons, tendon areas, vibrating period of piers, and exciting intensity of 1940 El Centro earthquake. The calculated results indicate that a peak base shear at the bottom of piers may be produced, when impacts occur. However, this value is still smaller than that of a conventional pier system (CPS). So that the merit of RPS is to remain elastic and to avoid any damage under the excitation of strong earthquake. And the seismic intensity to start the rocking of RPS can be set by adjusting the tendon area or post-tensioned forces in order to prevent rocking and termination of transport function of bridges under excitations of smaller intensity of earthquakes.