Abstract:Zhangjiagang bridge is chosen as research object, its finite element model (FEM) is built and updated based on the results of traffic excitation modal testing without stopping traffic, and applied to obtain the mass-normalized test mode shapes. Using the natural frequencies and mass-normalized mode shapes, the experimental modal deflection values of the given loads were calculated. In virtue of the comparison between the experimental modal deflection values and the measured values of static deflection, simulation study of some key issues and the effect of mode shape error to modal deflection, this paper discussed and represented the feasibility and availability of modal deflection method without stopping traffic based on operational modal analysis (OMA) to condition assessment of the bridge.