TECHNICAL CHALLENGES AND REFINEMENT RESEARCH ON WIND RESISTANCE OF LONG-SPAN BRIDGES

With the rapid development of long span bridges in China in past three decades, this paper presented technical challenges of wind resistance on three type long-span bridges, including flutter instability and control of suspension bridges, wind induced vibration of cable stayed bridges and control of wind-rain induced cable vibration, vortex induced vibration and control of arch bridges, and the refinements on aerodynamic flutter and buffeting of super long span bridges. It can be concluded that the intrinsic limit of a span length due to aerodynamic stability is about 1,500m for suspension bridges, and beyond or even approaching this limit, designers should be prepared to improve its aerodynamic stability. The cable-stayed bridges with a main span over 1000m have high enough critical flutter speed, but the main aerodynamic concern is the rain-wind induced vibration of long stay cables. Except one example of vortex-induced vibration, long-span arch bridges have no wind resistance problem. The refinement research on wind resistance of long-span bridges was also introduced with a full-mode flutter analysis method, the bridge buffeting frequency-domain analysis under skew wind action, the bridge flutter and buffeting reliability evaluation method based on second order theory and first passage theory, and the unveiling of a bridge flutter evolution process, generation mechanism and control law.