WIND TUNNEL TESTS ON AERODYNAMIC CHARACTERISTICS OF VEHICLE-BRIDGE SYSTEM FOR SIX-TRACK DOUBLE-DECKSTEEL-TRUSS RAILWAY BRIDGE

In order to investigate the aerodynamic characteristics of a vehicle and bridge system for multi-track double-deck railway bridges, a section model wind tunnel test was carried out using three-component aerodynamic force separating equipment, the crossed slot system. A six-track double-deck long-span cable-stayed railway bridge was taken as the research object. Aerodynamic forces on the vehicle, bridge, and various coupled combinations were measured. Aerodynamic interactions in various vehicle-bridge systems were studied, such as a single train at different track positions, two trains crossing on the same deck, and two trains running simultaneously on two decks. Moreover, the effects of different wind attack angles on the upper-layer vehicle were discussed as well. The results show that aerodynamic forces on the vehicle have large differences when positioned at different track positions. Since the upper deck of the railway bridge is comparatively wide, airflow separation caused by the front of the bluff bridge section might lead to the reattachment of the upper stream over the leeward vehicle, thus making the drag coefficient larger. The simultaneous passages of upper-layer and lower-layer vehicles impact the aerodynamic forces of each other when they are both on the windward side. Aerodynamic forces on vehicles are remarkably influenced by wind attack angles.