Wind tunnel study of the effect of wind barrier configurations on box girder aerodynamics and flow characteristics with different side ratios

This study investigates the effects of wind-barrier design parameters on the aerodynamic performance of bluff box girders and the near-deck wind environment for vehicles on long-span bridges. The experimental program includes aerodynamic force measurements, two-degree-of-freedom aeroelastic tests for vortex-induced vibration (VIV) and flutter, and near-deck wind-velocity measurements to assess the impact of barrier porosity, perforation orientation, height, installation configuration, and VIV-mitigation strategies. Two box-girder sections with B/D = 3.44 and 4.98 were tested to explore the role of deck geometry. Results show that the thin girder is more sensitive to wind-barrier-induced aerodynamic effects, experiencing higher near-deck wind speeds and larger vertical VIV amplitudes. Wind barriers effectively reduce wind speeds and improve vehicle stability but may also increase drag, amplify vertical VIV, and reduce flutter stability depending on configuration and girder type. Mitigation strategies are more effective for the thick girder, with limited benefit for the thin girder. Among the configurations studied, 50%-porosity barriers provide the best balance between wind shielding and aeroelastic performance, offering reductions in wind speed while maintaining acceptable VIV and flutter margins.