Evaluation and improvement of wind environment and vehicle safety on long-span bridge deck under strong crosswind

Ensuring the safety of various vehicles or trains passing through the bridge deck under strong crosswind is one of the most important topics for a long-span bridge. Based on the project of Xihoumen Bridge, which remains open to vehicle traffic until the incoming crosswind at the mid span reaches up to 36.5 m/s, the wind profiles near the deck surface above different traffic lanes were analyzed through numerical simulation and checked by both wind tunnel test and field measurement. The crosswind loadings were evaluated by the equivalent wind velocities for different vehicle models, confirming the need of adopting appropriate wind barriers to reduce crosswind speed above the deck surface. A total of 14 types of wind barriers were evaluated by the crosswind reduction factor and the best scheme was determined. The flutter and vortex-induced vibration (VIV) performance of the girder with selected wind barrier were also checked. Finally, the optimum solution, an adjustable wind barrier was proposed to reduce the wind-induced drag forces at high wind speed, which has already been used in Xihoumen Bridges.