Cofferdams are commonly used for construction or repair of permanent dams, oil platforms, bridge piers, etc., built within or over water. These cofferdams are usually welded steel structures, with components consisting of sheet piles, wales, and cross braces.

How are cofferdams used during foundation construction?

A cofferdam is a temporary structure designed to keep water and/or soil out of the excavation in which a bridge pier or other structure is built. When construction must take place below the water level, a cofferdam is built to give workers a dry work environment.

Where is the cofferdam?

The cofferdam is also installed around the main engine lube oil drain or sump tank, mainly to separate it from other double bottom tanks. The main engine is provided with the bed plate which carries the oil sump. The bedplate is mounted and secured to the engine foundation plate using chocks and holding down bolts.