Efficient Modeling and Safety Analysis of Train–Track–Bridge Systems Using a Unified Double-Coordinate Model

Dynamic analysis of high-speed train–track–bridge (TTB) system presents engineering challenges, particularly under complex conditions like track irregularity and crosswinds. Achieving a balance between computational efficiency and accuracy using the traditional substructure method, i.e. modeling the train and track–bridge separately and possibly performing iterations between them, can be difficult. In this paper, a practical unified three-dimensional (3D) TTB model is presented by using two coordinate systems: a stationary system for the track–bridge, and a moving system for the high-speed train. A wheel–rail interaction (WRI) element model is further extended such that the wheel and rail nodes in WRI element belong to moving and stationary systems, respectively, so as to make the train and track–bridge models consistently combined into one unified model. The unified modeling method simplifies computations and improves efficiency and stability. The modeling method has been implemented into an open source finite element platform, i.e. OpenSees, and applied for dynamic response analysis of a train traveling at 50[Formula: see text]m/s over a seven-span simply supported bridge. Running safety assessments are performed using three criteria, i.e. the Nadal criterion, Prud’homme criterion and unloading criterion, considering track irregularities and crosswind loads. The analysis results provide practically useful references for engineering.