Numerical analysis of high-speed railway bridges responses under track–bridge interaction induced by combined braking and temperature effects

Abstract

Track–Bridge Interaction (TBI) is an important consideration in the design of high-speed railway bridges, as longitudinal forces induced by train braking and temperature variations can generate additional rail stresses and rail–bridge relative displacements, which may affect the safety and performance of the track system. This study investigates the response of high-speed railway bridges under the combined effects of braking and temperature using a finite element model developed in MIDAS Civil based on a 40+64+40 m prestressed concrete continuous bridge. The effects of rail temperature increase, braking rate, train operating conditions, track slab longitudinal stiffness, and Rail Expansion Joints (REJs) were evaluated in terms of additional rail stress, rail–bridge relative displacement, and allowable rail temperature increase according to UIC 774-3. The results indicate that temperature is the dominant factor governing track–bridge interaction, while train operating conditions have only a minor influence on the overall system response. Reducing the track slab longitudinal stiffness decreases the additional compressive rail stress but increases the rail–bridge relative displacement. In contrast, installing REJs at the bridge ends increases the allowable rail temperature governed by the additional compressive rail stress criterion from 18.7 °C to more than 50 °C. However, the rail–bridge relative displacement becomes the governing design criterion, limiting the allowable rail temperature increase to 13.0 °C under the most critical braking condition. The results demonstrate that an appropriate balance between reducing additional rail stress and controlling rail–bridge relative displacement, together with an appropriate REJ installation location, is essential to satisfy the requirements of UIC 774-3 and ensure the safe operation of high-speed railway bridge systems.