Fatigue strength design for vortex-induced oscillation and buffeting of a bridge

Vortex-induced oscillation of bridges appears at relatively low wind speed. Large bridges are sometimes subjected to a large number of oscillation cycles by vortex-induced oscillation and buffeting. Fatigue strength design for these oscillations becomes an important problem for the design of a large bridge. To execute fatigue strength design reasonably for vortex-induced oscillation and buffeting, we put the characteristics of natural wind (i.e. wind direction, wind speed, and angle of attack) and the characteristics of bridge aerodynamics together. A computer makes fatigue strength design easy under several conditions. In this study, we propose a numerical stochastic method to calculate the number of cycles of vortex-induced oscillation and buffeting, considering that aerodynamic responses appear in a wide range of wind direction.