Food, air, water, shelter and transport are the basic needs of contemporary human being. To fulfill the needs of shelter and transport people make every inch of the earth land constructed with roads, building or other structures. Even a structure on water can be constructed even it is a very tedious job. Building in the water with concrete needs many smart methods used to overcome the problem of not standing of the concrete in the water. Cofferdams is one of the methods used for this purpose. Various types of cofferdams are used for construction of structures in water.
Considering the material used for the construction, cofferdams may be divided into:

Earthen cofferdam
Rockfill cofferdam
Single-walled cofferdam
Double-walled cofferdam
Braced cofferdam
Cellular cofferdam (Circular or diaphragm type)

More about each of them, in the link bellow.

Source.

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