Effects of wind barriers on the aerodynamic characteristics of bridge-train system for a road-rail same-story truss bridge

Wind barriers are commonly adopted to prevent the effects of wind on high-speed railway trains, but their wind-proofing effects are greatly affected by substructures. To investigate the effects of wind barriers on the aerodynamic characteristic of road-rail same-story truss bridge-train systems, wind tunnel experiments were carried out using a 1: 50 scale model. Taking a wind barrier with a porosity of 30% as an example, the aerodynamic characteristics of the bridge-train system under different wind barrier layouts (single-sided and double-sided), positions (inside and outside) and heights (2.5 m, 3.0 m, 3.5 m and 4.0 m) were tested. The results indicate that the downstream inside wind barrier has almost no effect on the aerodynamic characteristics of the train-bridge system, but the downstream outside wind barrier increases the drag coefficient of the bridge and reduces both the lift coefficient and drag coefficient of the train due to its effect on the train's wind pressure distribution, especially on the train's leeward surface. When the wind barriers are arranged on the outside, their effects on the drag coefficient of the bridge and shielding effect on the train are greater than when they are arranged on the inside. As the height of the wind barrier increases, the drag coefficient of the bridge also gradually increases, and the lift coefficient and drag coefficient of the train gradually decrease, but the degree of variation of the aerodynamic coefficient with the height is slightly different due to the different wind barrier layouts. When 3.0 m high double-sided wind barriers are arranged on the outside of the truss bridge, the drag coefficient of the bridge only increases by 12%, while the drag coefficient of the train decreases by 55%.