Abstract
This research investigates the dynamic stress–strain behavior of a railway bridge beam superstructure subjected to moving train loads using advanced computational modeling. The study employs MIDAS Civil software to develop a comprehensive three-dimensional finite element model of a typical railway bridge superstructure, incorporating realistic boundary conditions, material properties, and geometric configurations. The analysis examines the temporal variation of stresses, displacements, and internal forces as multiple train axles traverse the bridge at various operational speeds. The investigation reveals critical zones experiencing maximum dynamic amplification factors, which significantly exceed those predicted by static analysis methodologies. Dynamic load allowance coefficients are calculated for different train speeds, demonstrating a nonlinear relationship between velocity and structural response amplification. The model accounts for complex phenomena including moving load effects, inertial forces, and structural damping characteristics. Results indicate that dynamic effects become particularly pronounced at specific resonance frequencies, where vertical deflections and bending moments reach peak magnitudes. The findings provide essential insights for bridge design optimization, maintenance planning, and safety assessment protocols. This comprehensive dynamic analysis framework enables engineers to accurately predict structural behavior under realistic operational conditions, ensuring adequate service life and structural integrity of railway bridge infrastructure systems while maintaining required safety margins for contemporary high-speed rail applications.