Turbulence Effects on Vortex-Induced Dynamic Response of a Twin-Box Bridge and Ride Comfort of the Vehicle

The rapid growth of suspension bridges' span makes vortex-induced vibration (VIV) appears more and more frequently, and once it occurs the closure of the bridge results in considerable economic losses. Investigating the dynamic behavior of the bridge experiencing VIV and the vehicles running on it is thus imperative for providing a reliable guidance for the managers to make operation decisions. Nevertheless, most of the existing studies focus on VIV of bridges subjected to smooth winds, but a certain level of turbulence always exists in reality. The effects of turbulence on vortex-induced dynamic response of the bridge and ride comfort of the vehicles are not clear. This study thus develops a coupled vortex-vehicle-bridge system applicable to the multi-mode lock-in regions of a twin-box deck subjected to both vortex-induced forces and buffeting forces in a turbulent flow. The system is then applied to a real long suspension bridge with three types of vehicles subjected to either smooth or turbulent winds. The results from the case study show that the increasing turbulence mitigates vortex-induced responses of both the bridge and the vehicles and reasonably improves the vehicles' ride comfort. However, the buffeting forces induced by turbulent wind component should not be ignored when turbulence intensity becomes high.