Numerical Investigation of Flow and Scour around Complex Bridge Piers in Wind–Wave–Current Conditions

Abstract

A sea-crossing bridge is typically constructed in a marine environment with complex piers, and is susceptible to severe scour at the foundation. This study presents a numerical investigation on flow and scour around a complex pier, specifically focusing on a real-world sea-crossing bridge in China. A comprehensive CFD model incorporating hydrodynamic, free surface, sediment transport, and morphological models is employed for numerical modeling. Additionally, a wind shear stress model is considered to accurately simulate wind generation. The validation of the CFD model is achieved through comparison with experimental data of scour around a cylinder, demonstrating its capability to accurately replicate scour morphology and the temporal evolution of scour depth. Subsequently, the validated model is utilized for full-scale simulation of scour around the complex bridge pier under different wind, wave, and current conditions. The results indicate that compared to single piers with uniform cross-sectional shapes, flow patterns around complex piers are much more complicated. Scour predominantly occurs around the first row of group piles, while downstream piles experience less scour due to the sheltering effect from upstream piles. Furthermore, it becomes evident that the current exerts greater influence on pier scour than waves and wind, while the latter two factors primarily influence the superstructure of the bridge.