完全非平稳地震作用下斜拉桥随机响应分析

Analysis of Random Seismic Response of Cable-Stayed Bridge Under Fully Non-Stationary Earthquake Ground Motion

为研究粘滞液体阻尼器对斜拉桥随机地震响应的影响,结合虚拟激励法和等效线性化法对某大型斜拉桥进行完全非平稳地震响应分析。建立斜拉桥三维有限元模型,功率谱输入采用Conte和Peng提出的完全非平稳功率谱模型,通过对粘滞阻尼等效线性化处理并采用虚拟激励法将非平稳随机振动求解问题转化为一个确定性的逐步积分的过程,最后采用Monte-Carlo法验证虚拟激励法计算结果的正确性。结果表明:虚拟激励法可以准确地计算此类完全非平稳地震响应;通过在斜拉桥适当的部位设置粘滞液体阻尼装置,显著减小了斜拉桥的非平稳随机地震响应,可以有效改善结构的抗震性能。

To investigate the influences of the viscous liquid dampers on the random seismic re- sponse of cable-stayed bridge, the random seismic response of a major cable-stayed bridge under the fully non-stationary earthquake ground motion was analyzed by the pseudo excitation method and equivalent linearization method. The three-dimensional finite element model for the bridge was established and the power spectrum was input to the model, using the fully non-stationary analyti- cal earthquake ground motion model proposed by Conte and Peng. By way of the equivalent linear- ization of the viscous damping and by the pseudo excitation method, the solution of the non-sta- tionary random vibration issue of the bridge was transformed to a deterministic step-by-step inte- gration process and the accuracy of the calculation completed by the pseudo excitation method was finally verified by the Monte-Carlo method. The results demonstrate that the random seismic re- sponse of the cable-stayed bridge under the fully non-stationary earthquake ground motion can be calculated with good accuracy by the pseudo excitation method. The arrangement of the viscous liquid dampers on the appropriate parts of the bridge can significantly decrease the random seismic response and can effectively improve the seismic performance of the bridge.