天然基础上的重力式桥墩非线性地震反应分析

Nonlinear Seismic Response Analysis of Gravity Bridge Pier on Natural Foundation

软弱地基上的重力式桥墩,在强烈地震作用下, 有可能会发生桥墩基础提离现象。取上部结构恢复力模式为理想弹塑性模型,下部地基土采用有试验支持的无拉力Winkler弹塑性固结模型,分析了非线性地基土与非线性重力式桥墩相互作用体系下的地震反应,并对一重力式桥墩进行了计算分析。分析结果表明,对于天然浅基础上的重力式矮墩,地基的破坏有可能先于桥墩的破坏,在进行桥梁抗震设计时,考虑土与桥墩的共同作用是必要的。

The gravity bridge pier built on weak ground base may be lifted off the base during strong earthquake event. In this paper, the seismic response under interaction between the nonlinear ground soil and nonlinear gravity pier is analyzed, and a gravity pier is analytically computed by taking the bridge superstructure resilience model as ideal elastoplastic model, and by using non-tensile Winkler elastoplastic concretion model supported by tests for the ground soil. The (analysis) results show that for a short bridge pier on the shallow natural foundation, the damage of the ground base may take place earlier than that of the bridge pier. In the seismic design of bridges, it is necessary to consider the interaction between the ground soil and bridge piers.