Influence of aerodynamic interference of parallel adjacent bridges on coupled vibration of train-bridge system

There are two types of rail-cum-road bridges: railroad combined and railroad separated. Construction of railroad separated bridges is recommended due to their reduced potential safety hazards and ease of maintenance. In the case of separate construction, the aerodynamic interaction between parallel adjacent bridges results in a distinct flow field compared to that around a single railway bridge. In addition, the coupled vibration responses of the train and bridge under crosswind are also altered. To investigate the effects of aerodynamic interference between parallel adjacent bridges on the coupled vibration of train-bridge systems, we conducted a numerical simulation on a cable-stayed bridge built for both highway and railway. This involved calculating the three component coefficients of the train-bridge system both under parallel bridges and a single bridge. These numerical results were then compared to experimental data to verify the accuracy and suitability of the simulation method. The models for vibration coupling between train and bridge were established for single and parallel bridges based on the principle of total potential energy with stationary values in elastic system dynamics. The responses of the train-bridge system were assessed in two forms. Results indicate that in comparison to a single railway bridge, when the wind blows from the opposite direction, the drag coefficient of a railway bridge decreases while the lift and torque coefficients increase. The drag and torque coefficients of the train increase while the lift coefficient decreases. Further, when the train passes, both the lateral displacement of the bridge and the responses of the train increase substantially, while the vertical displacement of the bridge remains unchanged. On the windward side, the railway bridge shows no significant change in the three component coefficients compared to a single railway bridge. When a train passes, there is little change in the responses of both the bridge and the train. However, if the railway bridge is on the leeward side and the ambient wind speed is high, the effects of aerodynamic interference cannot be overlooked. © 2023, Central South University Press. All rights reserved.