Simulation of aerodynamic interference of steel cross-beams under staggered hoisting

Abstract

This study focuses on the irregular staggered bluff body structure formed by the main tower and its hoisted steel transverse girders of large-span bridges. Existing research is difficult to adapt to the dynamic spacing of hoisting, and cannot provide theoretical support for wind-induced safety control during construction. Taking the Chishi Bridge as the object, the SST k-ω turbulence model is used for numerical simulation. The vertical spacing ratio ( Q* ), horizontal spacing ratio ( S* ), wind speed (“v”), and wind angle of attack (α) are adopted as the core variables. The aerodynamic interference intensity is quantified by the three-component force coefficient interference factor, and the influence of each parameter on the aerodynamic flow around the suspended steel crossbeam is analyzed. The results show that under symmetric inflow, the base of lift and torque coefficients are small, and aerodynamic interference mainly manifests as changes in drag coefficient. When the spacing changes, the vortex coupling, blockage effect, and suction effect dominate the change in resistance. As the wind speed increases, all interference factors increase. The increase in wind attack angle has a relatively small impact on drag interference. However, it will cause a linear increase in lift and torque interference factors through the asymmetric flow field double amplification effect of staggered structures. The results reveal the flow field evolution mechanism of the staggered blunt body flow, providing a theoretical basis for wind-induced safety control during the steel crossbeam hoisting stage of the bridge tower.