基于地震引起动水作用的深海斜拉桥抗震性能研究

目前,深海大跨斜拉桥正在不断建设,其跨度的变化以及所处的深水环境使得在地震作用下桥梁受力更加复杂,地震作用下不但要考虑桩-土的相互作用,还要考虑地震引起的动水压力对结构的影响。为了分析地震引起的动水作用对斜拉桥动力特性和地震响应的影响程度,以及不同水深下动水力对深海斜拉桥地震响应的变化规律,基于一座现代大跨深水斜拉桥为工程背景,利用有限元软件建立三维模型,采用"m"法来考虑桩-土相互作用,用基于Morison方程的附加质量法来考虑地震引起的动水压力,结果表明动水对结构地震特性有较大影响,因此在斜拉桥抗震设计时动水作用不可忽略。

Study of Seismic Performances of Deep Sea Cable-stayed Bridges under Hydrodynamic Pressure Caused by Earthquake

At present,the long-span cable-stayed bridges in deep sea are being built in succession,and the changing spans and the deepwater environment make the bridge stress more complex under earthquake. Under the effect of earthquake,not only the interaction between pile and soil needs to be considered,but also the effect of hydrodynamic pressure on structures. To analyze the specific effect of dynamic characteristics of and the seismic response to the cable-stayed bridge under by the earthquakeinduced hydrodynamic pressure,as well as the change rules of seismic response caused by hydrodynamic pressure under different water depths,the finite element software is used to establish a three-dimension model,the"m"method is employed to address pile-soil interaction issues and the Morison-equation-based additional mass method is taken to calculate the hydrodynamic pressure caused by the earthquake in the case of a modern long span cable-stayed bridge project. The results show that the hydrodynamic pressure brings about great impact on structure seismic characteristics,and the hydrodynamic pressure should not be neglected in seismic design of the cable-stayed bridge.