Local Scour of a Large-Size Steel Cofferdam in Strong Tide Area

The Jiashao Bridge is located in the strong tidal area of the Qiantang river estuary. A large-size steel cofferdam was constructed to form the pile caps of its main bridge. The cofferdam construction was affected by local scour due to the cofferdam-tide-sediment interaction. It is important to know exactly how deep the local scour would be during sinking of the cofferdam. To ensure the smooth construction of the cofferdam, a formula was employed to forecast the scour depth of the cofferdam, which was further applied to guide the construction. The scour depth was also measured during the construction process. According to the measured results, the local scour mechanism and the maximum local scour pit depth of the cofferdam were analyzed. These offer technical supports and references to related projects of large-size steel cofferdam construction in strong tide area.