Experimental and numerical studies on the vortex-induced vibration of two-box edge girder for cable-stayed bridges

Abstract

Due to the blunt aerodynamic configuration, the edge-girder bridge deck may sustain severe vortex-induced vibrations (VIVs) that adversely affect bridge usability and security. In the present study, the VIV performance and the related aerodynamic mechanism of the two-box edge girder for a cable-stayed bridge are systematically investigated. Based on the flow pattern and vortex structure around the section simulated by computational fluid dynamics, it is inferred that the aerodynamic interactions of the large-scale vortices under the deck and the shedding vortices in the wake zone periodically change the fluctuating pressures on the section and induce the vibrations of the deck. Moreover, several aerodynamic mitigation countermeasures are designed. Their effects on the vertical VIV are experimentally investigated in detail. It is found that the vertical VIVs are considerably suppressed at different attack angles (−3°, 0°, and +3°) by installing the mini-triangular wind fairings, which can satisfy the bridge wind-resistant design requirements. Further numerical simulations show that after the installation of the effective countermeasures, vortex shedding in the wake zone is mitigated, and the strengths and distortions of large-scale vortices around the upper and lower surfaces of the section also decrease, thereby the vertical VIV is suppressed effectively.