Scour features of sea-crossing bridge piers

The local scour around bridge piers is one of the main safety influence factors of sea-crossing bridges in the nearshore region. Based on the survey data of six bridge piers of Jintang Sea-Crossing Bridge in Hangzhou Bay during 2014, 2015 and 2017, the scour effects around the bridge piers under bidirectional tidal flows were systematically studied. The general scour depth and the maximum local scour depth were analyzed respectively. It is found that the general scour depth is about 3.3~3.6 m, while the average local scour depth is about 8.3 m. The local scour holes extend in both upstream and downstream directions with elliptic shapes due to bidirectional tidal flows. The longitudinal length of scour hole is approximately linear with the maximum local scour depth with a ratio of about 10~12. While the scour hole width of each bridge pier is nearly the same, about 4~5 times the pier width. In addition, there is no obvious correlation between the width of scour hole and the maximum local scour depth. The research results about scour depth prediction and scour profile characteristics can provide a reference for sea-crossing bridge foundation design, maintenance and scour protection.