Caisson Construction

Caisson construction is a civil engineering technique built around the caisson, a watertight retaining structure that keeps a work site dry so foundation work can be carried out below the water line, used for example to build the foundation of a bridge pier, to construct a concrete dam, or to repair a ship. A caisson is built so that the water inside it can be pumped out, keeping the enclosed work area dry; when an open caisson is used to build a pier and it is impractical to reach suitable bearing soil, friction piles can be driven to create a suitable sub-foundation, with the piles tied together by a foundation pad on which the pier column is then erected.