Effect of Temporary Barriers on the Vortex-Induced Vibration Performance of a Long-Span Bridge during Maintenance Periods

During maintenance of an in-service long-span bridge, temporary barriers (TBs) are often employed on the deck for construction isolation, which will change the aerodynamic profile of the bridge girder and potentially cause large-amplitude vortex-induced vibrations (VIVs); for instance, water-filled barriers have triggered significant VIVs of the Humen Bridge during maintenance. To address this issue, it is crucial to investigate the aerodynamic effects of TBs on the bridge girder. Taking a long-span suspension bridge with a streamlined box girder as the engineering background, this paper provides a case study of the effects of TBs on VIV performance of the bridge as well as aerodynamic optimization of TBs through wind tunnel tests and computational fluid dynamics simulations. Results indicate that (1) continuous TBs with constant height located near the side barriers will introduce large-scale leading-edge separated vortices, which then reattach on the surface of the deck, leading to significant vertical and torsional VIVs of the girder; and (2) either high–low TBs arranged alternately or segmented TBs arranged at intervals can disrupt the spanwise correlation of the large-scale leading-edge separated vortices, thereby suppressing the VIVs, and among them, TBs arranged at intervals with a gap ratio no less than 1:6 can successfully prevent VIV. This study provides a valuable reference for the wind resistance of in-service bridges during maintenance.