基于场地-结构整体模型的桩基斜拉桥地震反应分析方法

针对我国普遍采用的大跨度桩基桥梁，应用无限元有限元土体边界、桩土面面接触算法和显式求解技术，提出了场地结构整体模型的地震反应分析方法.以一座主跨为202.5 m+300.0 m的独塔斜拉桥为工程实例，构建了河谷场地桥梁整体有限元动力模型，研究了二维河谷场地对该斜拉桥纵向地震反应的影响，分析了基础附近扰动场地震动的特点.结果表明，场地中不同河岸高度和二维土层分布会对主塔处地震动的短周期分量产生一定影响，对结构短周期振型产生的地震力有较大影响；扰动场的地震动中接近基础振动频率的分量得到了加强，和自由场的地震动有显著区别，但长周期的分量变化较小.

seismic analysis method for cable-stayed bridges with pile foundation based on site-structure integrated model

Site structure integrated models are established on the basis of the finite element infinite element boundary technique, surface to surface contact algorithm and time domain explicit analysis for a 202.5m+300m single tower cable stayed bridge with a group pile foundation. Research on the longitudinal seismic response of the bridge is made with the integrated model which focuses on the effect of valley site and the properties of the ground motion under soil structure interaction. The results indicate that the shape of the valley and the two dimensional soil layer will affect the short period component of the ground motion and the response of the structure. The soil structure interaction strengthens the components of ground motion near the frequency of the pile foundation, while it has little effect on the components for a longer period.