To provide a water area cofferdam construction method which is not interfered by existing other structures and which executes swiftly and definitely a cut-off work by cofferdam so that the work may not interfere with the navigation of a ship.
A cofferdam of a foundation of a structure is immersingly constructed underwater. In this case, the irregularly-shaped top of the bottom of the independent foundation (a) where the cofferdam is set up, is formed horizontally with foundation concrete 1. A pier (b) is surrounded with a cylinder- shaped steel-made frame 2 which coffers temporarily a construction water area and the steel-made frame 2 is pressed down and fixed with the foundation by way of an expansion jack 5 provided on a car exclusive road A, thus hollowing the interior of the steel-made frame 2 and forming a working space for reinforcing the pier.
MIZUNO TETSUYOSHI
ARATA YUKINOBU
