非一致地震激励下大跨斜拉桥非线性响应计算

基于随机过程理论关于幅值、相位与功率谱的关系式,采用二维相干非一致激励功率谱模型,根据场地地震动参数合成人工地震波,考虑波动传播效应和多点激励效应,分析了某座跨长江的大跨度斜拉桥在地震激励下的空间非线性响应特性,计算了桥梁结构关键部位在地震力作用下的响应特性,并与一致激励下对应响应量进行了比较。认为非一致激励下大跨斜拉桥关键部位的某些响应量大幅增加,反应了进行非一致响应分析的必要性。

Analysis on Nonlinear Seismic Response of Long-span Cable-stayed Bridge Subjected to Asynchronous Excitation

The artificial seismic waves were simulated according to the earthquake parameters of the site,with the relationship between amplitude,phase angels and power spectra in stochastic process being used and a two-dimensional coherency function and asynchronous excitation power spectral density(PSD) model employed as well.A long-span cable-stayed bridge across the Yangzi River subjected to the spatial seismic excitation was analyzed,during which course the effects of geometric nonlinear,traveling wave and multipoint(excitation) were considered.Several results of concerned sections under asynchronous excitation and synchronous excitation were provided,comparison of which showed the some responses amplifying with asynchronous condition.Conclusions supported the necessity of(asynchronous) responses analysis.