Numerical methods for investigation of destructive wind energy dissipation by bridges

Many bridges are located at especially unfavourable places considering the local wind power and turbulence. Therefore it turns out that finding an optimal balance between structural safety and erection costs depends strongly on a proper wind modelling and investigation. Several aspects must be taken into account for the wind design. The effect of wind gusts and randomly distributed wind velocity and direction must be considered in the framework of a wind buffeting analysis. This requires detailed information about the power spectral density and cross correlation of the local wind events. The air flow pattern strongly influences the resulting forces. Since a fully coupled model for randomly oncoming flow and resulting wind forces is too complex, the forces are derived from steady state CFD calculations in general. In this paper, the theoretical background of the applied analysis methods is outlined and practical examples for different long span bridges are given.