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

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.