Suppression efficiency of the maintenance rail position and guide vanes on vortex-induced vibrations of a streamlined closed-box girder

The vortex-induced vibration (VIV) of the streamlined closed-box girder is greatly affected by the attachments. Herein, the VIV performance and suppression measures of a streamlined closed-box girder with an aspect ratio of 12.425 are investigated through 1:25 scale section model wind tunnel tests and numerical simulations. Severe torsional VIVs at 0° and +5° attack angles are observed in wind tunnel tests. Subsequently, the triggering mechanism is explored through the computational fluid dynamics (CFD) method and dynamic mesh technology. Furthermore, it is pointed out that the suppression measure design should focus on the maintenance rail. After that, the influence of the maintenance rail position and installing guide vanes beside the rails on the VIV performance is investigated systematically, and the suppression mechanism is studied through the CFD method. The results show that the leading-edge vortex above the girder and the wake vortex under the inclined web cause the VIV, and the former plays a major role. Moving maintenance rails inward and installing dual-side or inside guide vanes beside the rails can reduce the VIV. These two measures share a common suppression mechanism: reducing the leading-edge vortex above the girder while eliminating the wake vortex under the inclined web. Finally, an optimal measure of setting maintenance rails at l/Wb = 1/10 and installing inside guide vanes is proposed.