Study on VIV performance of streamlined steel box girder of a sea-crossing cable-stayed bridge

The frequent occurrence of vortex -induced vibrations (VIVs) poses significant challenges for the operations of large -span sea -crossing bridges subjected to wind loads. A wind tunnel test device for large-scale section models is developed for a sea -crossing bridge to investigate the VIV performance of a streamlined box girder. A new type of aerodynamic countermeasure combining horizontal stabilizers and deflectors is proposed to address vertical and torsional VIV mitigation. To achieve optimal control effects, adjustments are made to the layout of deflectors and the width of horizontal stabilizers. The effects of varying structural damping ratios and low turbulence on vertical VIVs are also thoroughly examined. The VIV triggering mechanism of the girder by maintenance rails is revealed through numerical simulations using the Shear Stress Transport (SST) k - omega model. Finally, the suppression mechanism of the countermeasures is elucidated. The instantaneous vorticity distribution indicates that implementing the countermeasures effectively reduces the size of alternating shedding vortices on the trailing edge of the main girder. This research provides valuable insights into the VIV mitigation of streamlined box girders.