Dynamic Analysis of the Hangers in High-Speed Railway Arch Bridge Based on Train–Bridge Interaction Simulation and Field Measurement

The hangers represent the crucial load-bearing component of arch bridges and are susceptible to dynamic vehicle load. However, little effort has been made to carry out dynamic analysis of arch bridge hangers under high-speed train loads. This paper presents an investigation of the dynamic behavior of the arch bridge subjected to high-speed train with emphasis on the flexible hangers, using train–bridge interaction simulation and field measurement data. Coupled train–bridge system model composed of three-dimensional train model, bridge model, and wheel–rail interaction model is established to account for hanger transverse vibration, spatial train loading, and track irregularity excitation, among others. Vibration data of bridge components including the hanger are measured through field test on a typical high-speed railway tied-arch bridge. A total stress-based dynamic amplification factor is subsequently proposed to describe the effect of hanger transverse vibration. The influence of significant parameters such as train speed and track irregularity on the dynamic effects of hangers is examined by the experimentally validated train–bridge interaction model. It is found that the dynamic responses of the hangers are considerably different from bridge global responses. In-plane and out-of-plane transverse vibrations of the hanger result in a large increase in the hanger dynamic effects which prove to be sensitive to train speed, track irregularity, train loading position, etc. Moreover, the dynamic amplification factor formula in the current high-speed railway code may not be sufficient to characterize the dynamic amplification of hangers under operating conditions.