Main girder damage detection and verification of cable-stayed bridges based on cable force model updating

For a quick damage detection of cable-stayed bridge girders, a cable force-based model updating method was proposed. First, a finite element(FE) bridge model was established and validated. The updated segments were selected by a selective preference principle and the segmental stiffness change was regarded as the updating variable during the damage detection. The measured cable forces during the bridge operation were regarded as the tracing target for the model updating. Then, the stiffness of selected segments was updated by setting different values of the stiffness reduction coefficient until the cable forces in the FE model were the same with the measured values. The values and the positions of these stiffness reduction coefficients represented the levels and locations of the damages in the main girder, respectively. The Bengbu Huaihe bridge was selected as a case study. The design condition of this bridge was determined by the original data from the loading test before bridge opening. The local stiffness of segment joints and the measured cable forces during the operation were regarded as the identification variable and tracing target, respectively. The identification results based on the proposed method were verified by the measurement data and the assessment conclusion in the bridge inspection reports. The analysis results show that the proposed method is logical and economic. It is suitable for quick assessment and change detection for cable-stayed bridges and can be integrated into routine projects of bridge inspection. © 2019, Editorial Department of Journal of Southeast University. All right reserved.