AMBlENT VlBRATlON．BASED FE MODEL CALlBRATlON OF A PRESTRESSED CONCRETE CABLE．STAYED BRlDGE

摘要

San-Xian-Zhou Bridge,over the Minjiang River,Fuzhou,the capital of Fujian Province,P.R.China, is a single-tower cable-stayed bridge,with the main span of 238m.The main girder is a prestressed concrete box girder.The bridge was opened to traffic in May,1 999.To assess the current service condition,the field ambient vibration tests induced by wind and normal traffic were carried out to determine the real dynamic characteristics and each stay cable tension force.In this paper,an initial three-dimensional finite element(FE)model of the bridge was developed to perform the dynamic analysis,and then calibrated in terms of ambient vibration test results.The effects of some important parameters,such as the deck added mass,cable tension,dead load,and boundary conditions,were discussed and some important conclusions were extracted.It is demonstrated that the prediction of the calibrated FE model agreed well with the field testing results.The calibrated FE model can be used as the baseline model for the long-time monitoring and condition evaluation of the bridge.