Modal Analysis and Condition Evaluation of Substructures for Simply Supported High-Speed Railway Bridge Based on a Simplified Model

Abstract

The condition of substructures in high-speed railway (HSR) bridges is crucial to the safety of the railway operation. However, research on the condition evaluation of substructures in HSR bridges is very limited. In this paper, a simplified model for a single pier that considers the effect of a pier–beam coupling will be proposed to simulate the multiorder vibrations in the local pier–beam system by distributing the mass of the beam to the top of the adjacent piers. A systematic procedure that is based on the simplified model and finite-element (FE) model updating will be adopted for the modal analysis and condition evaluation of the bridge substructures. Numerical simulations will be conducted on a 10-span simply supported HSR bridge to validate the proposed model and method. Furthermore, field measurements will be conducted on an HSR bridge to assess the health condition of the substructures. The results show that the modal frequencies and damage that were identified with the simplified model agreed well with those of the local pier–beam system. The proposed simplified model could be suitable for the modal analysis and condition evaluation of HSR bridge substructures.