中文摘要：

选取福建省下白石大桥（连续刚构桥）作为研究背景,建立下白石大桥的ANSYS有限元模型.使用基于MATLAB平台的模态分析软件MACEC,采用随机子空间法（SSI）对下白石大桥进行模态分析.根据分析结果,对下白石大桥有限元模型参数进行修正;利用修正后的有限元模型采用瞬态动力学分析功能求得其在移动荷载作用下的纵向应变时程曲线和动力影响线.为下一步车辆荷载效应评估奠定基础.

英文摘要：

Selecting the continuous rigid frame bridge-Fujian Xiabaishi bridge as research background, the ANSYS finite element model of Xiabaishi bridge is established. Adopting the modal analysis software MACEC based on the MATLAB plat- form, the Xiabaishi bridge is model analysed by using stochastic subspace （SSI）. According to the results of modal analysis, the finite element model parameters of Xiabaishi bridge are corrected; Longitudinal strain time travel curve and influence line for dynamic under moving load are obtained through the transient dynamics analysis under the modified finite element model. All of that make the foundation of vehicle load effect evaluation.