Abstract：A dynamic evaluation method for railway simplified-supported bridge substructures based on modal parameters and optimization theory is proposed. With different combinations of measured lateral integral, lateral local and longitudinal local vibration mode parameters as input data, the FE model updating technique is used to identify the physical and mechanical parameters of substructures, so that damage of pier shaft, foundation and bearings in the substructure system can be located and quantified. Furthermore, the evaluation criteria and evaluation procedure for health condition are established to assess the integral and local health conditions of members in substructure system. Two railway bridges were tested and their health conditions were evaluated based on the proposed evaluation criteria. The analysis results agree well with the in-situ evaluation results, validating the effectiveness and accuracy of the dynamic evaluation method proposed for railway simply-supported bridge substructures.
