地基水平运动时高桥墩的动力屈曲

Dynamic buckling of the high pier under the foundation horizontal motion by earthquake

考虑大变形的影响,建立了高桥墩在地震波冲击下引起的地基水平运动时的非线性动力学基本方程式;通过位移形函数假设,采用伽辽金积分方法得到了时间变率的动力学控制方程;对时间变率的非线性微分方程进行数值求解,给出了同一地震波不同强度下高桥墩的位移响应曲线以及从产生横向振动到失稳的全过程;得到了地震波冲击时高桥墩失稳的临界地震加速度acr和失稳时刻。通过数值算例比较了地震波幅值、高桥墩柔度、桥面质量大小对位移幅值响应、临界地震加速度、失稳时刻等参数的影响。算例表明当发生7.5级以上地震时,桥墩会有较大程度的破坏。

Considering the influence of the large deformation,the non-linear dynamic equations of high pier under the foundation horizontal motion by earthquake are established.By supposing the displacement shape function and applying the Galerkin method,the dynamic equations about time are obtained.By numerical calculation,the displacement response curves of the high pier under the foundation horizontal motion by earthquake with different magnitude and the overall process from the transverse vibration to the instability of the high pier are given.The critical seismic acceleration acr and the instability time are obtained.The influence of the different seismic peak,the slenderness ratio and the weight of the bridge on the displacement response,the critical seismic acceleration and the instability time are analyzed.The example shows that when an Ms7.5 or above earthquake happens,piers will have a greater degree of damage.