Prediction of vortex-induced oscillations of a bridge girder with span-wise varying geometry

There are cases where it is difficult to predict the amplitude of vortex-induced oscillation accurately by using a single wind tunnel 2D model. An example of them is proposed sine-curved hybrid cable-stayed bridge girder with span-wise varying geometry discussed in this study. First, the aerodynamic damping force was measured for five 2D models in a wind tunnel. Next, a linearized method for 3D numerical analysis was prepared and then applied to predict the amplitude of the oscillation for this bridge. Since one of the triangular fairings examined was found to be effective in suppressing the oscillation, it was decided that the bridge girder with this fairing should be included in its detailed design. Also, the precision of the solution obtained by the numerical analysis was found to be sufficiently high for the case where much smaller number of 2D models was used.