Scour characteristics of middle approach bridge foundations in Hangzhou Bay sea-crossing bridge

Abstract

To evaluate and predict the scour status of the Hangzhou Bay Sea-crossing Bridge well, the general and local scour characteristics in a strong tidal area were analyzed based on field data of 133 middle approach bridge foundations. It is found that the scour holes are elongated upstream due to a stronger flood tide. The general scour depths are about 2-4m, while the local scour depths are about 4-8m, which illustrates that the local scour depth is about twice the general scour depth. In addition, the existing equations, including HEC-18 and OH equations, both overestimate the scour depth. Based on field data, an equation for local scour is established, and the relative errors are both within 20%, which can be used to predict local scour depth in conditions of strong tide and cohesive seabed.