洪塘大桥六跨预应力连续梁的动力特性分析

Study on the dynamic characteristics of a prestressed concrete continuous bridge with six spans

以福州市洪塘大桥为背景,进行了该桥六跨预应力混凝土连续梁桥部分的环境振动实验,利用时域 的随机子空间识别法(SSI)进行识别桥梁的动力特性．进一步地,利用ANSYS建立了全桥三维有限元模型并 进行了理论模态分析,理论计算和实测结果吻合较好．此类测试与分析有助于桥梁的状态评估与维修加固．

The dynamic characteristics of a prestressed concrete continuous girder bridge, which are parts of the Hongtang bridge, located in west suburb of Fuzhou County, Fujian Province, were investigated. The field ambient vibration tests were firstly carried out. The stochastic subspace identification (SSI) method in time domain was used for the output - only modal identification in vertical, horizontal and lognitudinal directions. Furthermore, a 3 - D finite element model was constructed and the theoretic modal analysis was performed to generate natural frequencies and mode shapes of the bridge. The finite element model was validated to match the testing natural frequencies and mode shapes of the bridge. It is demonstrated the results from ambient testing and analysis of dynamic characteristics can serve for condition evaluation, strengthening and rehabilitation of the prestressed concrete continuous girder bridge.