Numerical evaluation of vortex-induced vibration amplitude of a box girder bridge using forced oscillation method

The evaluation of the amplitude of the vortex-induced vibration (VIV) of a long-span bridge is necessary to implement a wind-resistant design. The development of high-performance computing has led to the use of computational fluid dynamics (CFD) in this domain, but the evaluation of VIV amplitude using the free vibration method in CFD incurs a high computational cost because of the small negative aerodynamic damping in the wind speed region of VIV. In this study, the use of flutter derivatives based on the forced oscillation method with a large eddy simulation is proposed for evaluating the VIV amplitude to reduce computational cost. The heaving VIV amplitude of a box girder was evaluated using simulated flutter derivatives and the results were validated by corresponding free vibration wind tunnel tests. Because the aerodynamic damping obtained by the flutter derivatives showed a clear dependence on the oscillation amplitude, the VIV amplitude can be evaluated using the proposed method. The effects of the spanwise domain size and Reynolds number were also significant.