Experimental studied on suppressing vortex-induced vibration of closed-box girder bridges with various moveable guide vanes

A new moveable guide vane with the combination of the spring and guide vane was proposed to suppress the vortex-induced vibration (VIV) of closed-box girder bridges. This paper studies the influence of two important parameters (i.e., horizonal length and spring stiffness) of a moveable guide vane on controlling the VIV of a super long-span suspension bridge with closed-box girder by using VIV control tests. The VIV test of 1:50 scaled ratio of sectional model of the original closed-box girder under three wind attack angles were firstly conducted. The suppression ratios of vertical and torsional VIV displacements of the closed-box girder as well as the movement characteristics of moveable guide vane were then analyzed, respectively. The results show that the movable guide vane could significantly reduced the Root Mean Square (RMS) values of VIV displacement of the closed-box girder are after installing, especial for the torsional VIV displacement. A moveable guide vane with a relative smaller horizontal lengths or a relative larger spring stiffness could produce a better outcome of VIV control. The double VIV amplitude of the moveable guide vanes results in the energy dissipation of the closed-box girder in the lock-in VIV wind speed region, while the vertical displcement of the moveable guide vane are close to those of the closed-box girder in non-VIV wind speed region. Besides, the nonlinear exponential fitting function could effectively reflect the relationship among the wind speed, the VIV displacement of the MGV and the closed-box girder.