Wind Tunnel Investigation and Numerical Simulation of Flow Characteristics Around the Enclosed Railing Steel Box Girder Section

The rapid development of computational fluid dynamics has facilitated its widespread application in bridge design and wind engineering. This paper employs large eddy simulation (LES) to investigate the impact of non-uniformly distributed closed railings along the span of a bridge on flow characteristics, particularly focusing on a steel box girder section and the mechanism for suppressing vortex-induced vibration (VIV). The study delves into various VIV-related flow parameters such as velocity distribution, evolution of three-dimensional vortex structures, and pressure distribution on the girder surface. The findings reveal that significant negative pressure emerges on the leeward side of the upstream bridge deck when the outer railings are closed, resulting in increased downstream airflow in the spanwise direction and diminished vortex energy downstream. Moreover, it is observed that the negative pressure exerted by the bridge deck leads to significant dissipation of vortices induced from the downstream, consequently reducing VIV amplitude. The vibration suppression mechanisms of the two measures are compared and discussed to explore their potential for application in actual design considerations.