Experimental study on suppression of vortex-induced vibration of bridge deck using vertical stabilizer plates

Abstract

Despite the wind-resistant design performed during the design stage, an existing bridge may still experience severe vortex-induced vibrations (VIVs) because of the installation of new affiliated facilities during its operation period. Therefore, it is necessary to apply control measures to suppress the VIV induced by such changes in configuration. In this study, the VIV performance of a streamlined box girder bridge during the installation of new auxiliary piping system was investigated through a series of sectional model tests and flow visualization tests. Severe vertical VIVs of the bridge used in this study were observed at lower wind speed ranges during wind tunnel tests. Based on the flow pattern around the sectional model, it was inferred that the flow across the deck bottom surface was entirely separated by the new pipelines, which resulted in the periodic generation of shedding vortices in the wake zone and induced deck vibration. Twin downward vertical stabilizer plates (TDVS) were found to be an effective aerodynamic countermeasure for improving the VIV performance of the bridge and could significantly decrease the amplitude of the vertical VIV motion. Additional flow visualization investigations showed that after the TDVS were installed, the vortex shedding in the wake was mitigated, and the location of the vortex shedding was further away from the deck, and hence, considerably suppressed the vertical VIVs. It was found that the effectiveness of the TDVS in improving the aerodynamic performance was significantly dependent on the TDVS parameters, i.e., the plate height and spacing between plate elements. The optimal values of these parameters were correspondingly identified for the bridge deck used in this study after a comprehensive evaluation.