强震作用下独塔斜拉桥模型的非线性动力响应分析

Nonlinear dynamic response analysis of cable-stayed bridge with single tower under strong earthquake excitations

建立了基于隐式积分和显式积分的2种有限元模型,对独塔斜拉桥振动台试验中得到的地震响应特性及其破坏模式进行了模拟.然后,利用基于隐式积分的有限元模型,分析了行波效应和索塔梁耦合振动对独塔斜拉桥地震响应特性的影响.结果表明:基于隐式积分的有限元模型可以有效地模拟斜拉桥发生破坏前的地震响应特性,而基于显式积分的有限元模型则可用于模拟独塔斜拉桥在地震作用下发生破坏的全过程;由于输入地震波频谱效应以及视波速各异,行波效应对独塔斜拉桥地震响应特性的影响各不相同;在强震作用下,模型会发生索塔梁耦合振动,导致主塔的纵桥向位移响应明显增加.

An implicit integration finite element model and an explicit integration finite element model were established to simulate the seismic responses and failure modes of a cable-stayed bridge model with single tow er in shaking table tests. Then,according to the implicit integration finite element model,the influences of the traveling wave effect and the tow er-cable-girder coupling vibration on the seismic responses of the cable-stayed bridge with single tow er were analyzed. The results show that the implicit integration finite element model can simulate the seismic behaviors of the cablestayed bridge with single tow er before failure. The explicit integration finite element model can predict whole the failure process of the cable-stayed bridge with single tow er under strong earthquake.The influences of the traveling wave effect on the seismic responses of the cable-stayed bridge with single tow er are different due to the difference of frequency spectral characteristics and wave velocities. Under strong earthquake,tow er-cable-girder coupling vibration occurs,leading to the significant increase of the longitudinal displacement response of the main tow er.