地震与波浪联合作用下斜拉桥桥塔的响应分析

Response analysis of cable-stayed bridge tower under combinedaction of earthquake and wave

为了研究跨海桥梁在地震与波浪联合作用下的响应规律与破坏机制,以一座斜拉桥为研究对象,选取了适用于3类不同场地的El-centro波、Taft波、天津波3条地震波,取不同的地震峰值加速度与无水、水深8 m、水深16 m和水深24 m组合成不同的工况,分别对斜拉桥进行地震和波浪联合作用下的动态时程分析和Pushover分析,并将两种方法的分析结果进行对比。结果表明:在地震与波浪联合作用下,地震加速度的峰值越大,动水压力对斜拉桥桥塔响应的相对影响越小;水深越深,斜拉桥桥塔受到动水压力的影响越大;在水深较浅的低海况下,地震力占主导地位;在水深较深的高海况下,波浪力占主导地位;Pushover方法与动力时程分析的结果相一致,在对斜拉桥进行地震与波浪联合作用下的非线性响应分析时,Pushover分析方法具有较高的精度且计算更加简便,更适用于工程实际。

In order to study the response law and failure mechanism of the sea-crossing bridge under the action of earthquake and wave,a cable-stayed bridge was selected as the research object.Three seismic waves,namely Elcentro wave,Taft wave,and Tianjin wave,were selected,which were suitable for three different types of sites.Different seismic peak accelerations were combined with anhydrous,8 m water depth,16 m water depth,and 24 m water depth to form different working conditions.The dynamic time-history analysis and Pushover analysis on cable-stayed bridges under combined action of earthquake and wave effects were carried out,and the analysis results of the two methods were compared.The results show that under the combined action of earthquakes and waves,the larger the peak value of seismic acceleration,the smaller the relative impact of hydrodynamic pressure on the response of cable-stayed bridge towers.The deeper the water depth,the greater the impact of hydrodynamic pressure on the tower of the cable-stayed bridge.In low sea conditions with shallow water depths,seismic forces dominate.In deep sea conditions with high water depths,wave forces dominate.The Pushover method is consistent with the results of dynamic time-history analysis.When analyzing the nonlinear response of cable-stayed bridges under the combined action of earthquakes and waves,the Pushover analysis method has high accuracy and simpler calculation,so it is more suitable for engineering practice.