Wind resistant design for long span suspension bridges

摘要

Considering the trend of longer bridges in the future, aerodynamic instability plays a major role in their design. In this paper, the aerodynamic characteristics and the efficiency of the structural countermeasures for aerodynamic instability of long span suspension bridges are discussed using the newly developed direct flutter analysis method for longer spans than the Akashi Kaikyo Bridge (main span 1990 m). For suspension bridges longer than the 2000 m-class the aerodynamic characteristics become worse as shown by the drop in flutter wind speed and the coupled torsional—vertical flutter response. The efficiency of the structural countermeasures for long span suspension bridges decreases for spans longer than 2000 m. Finally, the mode-control countermeasure (strengthening of deck rigidity in some region) was proved to be efficient in gaining stability against flutter.