Study on the Effect of 2D and 3D Train Modeling in Vehicle-Bridge Interaction

The Extended Modified Bridge System (EMBS) method provides a consistent framework for decoupling the vehicle–bridge interaction (VBI) problem, significantly simplifying the analysis compared to coupled approaches. This decoupling enables independent bridge analysis by incorporating additional damping, stiffness, and loading terms into the governing equation of motion (EOM) to account for the dynamic influence of the vehicle. Subsequently, the EMBS method solves the EOM of the vehicle subsystem by using the bridge response as an input. Initially, the EMBS method was proposed for two-dimensional (2D) vehicle-bridge systems. This study extends the EMBS method to analyze VBI problems in three-dimensional (3D) space to capture more realistic scenarios. In this context, the study numerically examines a steel arch bridge with a composite concrete deck subjected to dynamic loading from a passing train. It also compares bridge and vehicle response obtained from 2D and 3D models through numerical simulations, evaluating whether—and to what extent—2D model results resemble those of the 3D model.