Effect of Hooked Collar Structure on Local Scour Reduction Around Large Stepped Caisson Foundation

Large stepped caisson foundation has been widely used in long-span deepwater bridge in recent years, and local scour caused by the structure has also been concerned. The hooked collar structure has been proposed to reduce the local scour around novel stepped caisson. Laboratory experiments were conducted to investigate the response of local scour of stepped caisson to different hooked collar height. The experimental results show that the local scour depth increases first and then decreases with the rise of hooked collar height under steady flow and uniform sediments. Further analysis indicates that the optimal hooked collar height to minimize the local scour related to the stepped width. The quantitative relationship between dimensionless scour reduction capability and dimensionless hooked collar height is presented in this study, which is able to provide reference for engineering application of relevant structure.