Aerodynamic interference effects between a triple-box girder and trains on aerodynamic forces and vortex-induced vibration

Wind tunnel tests were carried out to investigate the aerodynamic interference between a triple-box girder and trains, involving static aerodynamic forces and vortex-induced vibrations (VIVs). Static and dynamic sectional models of the girder and trains were employed for aerodynamic force measurement and VIV test, respectively. Results indicate that the aerodynamic interference effect on static aerodynamic forces of both the girder and trains is remarkable. When a single train exists, the horizontal position of the train has a small effect on aerodynamic coefficients of the girder. When two trains meet on the girder, the drag coefficient of the girder is significantly reduced compared with that of without train or with a single train; besides, during the whole meeting process, aerodynamic forces of the leeward train first drop and then increase suddenly. The fluctuation of aerodynamic force could cause redundant vibration of the train, which is unfavorable for safety and comfort. A train on the girder could worsen the girder VIV performance: a new vertical VIV appears in the triple-box girder when a train is on the girder, and the torsional VIV amplitude increases significantly when the train is on the windward side.