Immersed tunnel cost reduction

Describes a construction system originally developed for ship hulls that can substantially reduce the cost of immersed or submerged floating tunnels. The tunnel can have any diameter or wall thickness and can be a monolith of any length permitted by site conditions. A tunnel might have only two segments in a “V” profile joined under the center of the navigation channel or have three sections consisting of two approach segments and a long monolithic section moored below navigation depths. Tunnel segments are built directly on the water at the site or nearby in low-cost floating formwork with portable wet-mix shotcrete equipment operated by local unskilled labor under the direction of a trained supervisor. Welded wire fabric or preformed rebar mat is placed by the laminating crew, eliminating need for skilled steel workers to erect and tie reinforcing. No graving dock, shipyard, towing, or heavy lifting equipment is required.