Vertical vortex-induced vibration performance of split triple-box girders with various ancillary facility configurations

Wind tunnel tests were conducted to systematically investigate the effects of maintenance rails, individual auxiliary facilities, and various combinations on the vertical vortex-induced vibration (VIV) of triple-box girders. Results indicate that highway wind barriers intensify vertical VIV, while railway wind barriers and crash barriers help to mitigate it. Computational fluid dynamics (CFD) was utilized to analyze the aerodynamic pressure distribution and flow field characteristics of the triple-box girder. Flow separation at the top of the highway wind barrier was identified as a primary driver of VIV. Railway wind barriers effectively reduce VIV by creating low-pressure regions on the railway box's top surface, preventing the main girder from generating periodic aerodynamic forces. Additionally, crash barriers reduce VIV by suppressing vortex formation at the trailing edge of the upstream box. The two vibration suppression measures were proposed based on the VIV-inducing mechanism and validated through experiments and flow field analysis.