This study describes the design and benefits of a new type of caisson called the “precast form caisson”. Many recently developed caisson construction methods use full-precast plates, whose joints are poor in durability and load bearing capacity. Design and construction methods that compensate for these weaknesses by using full-precast members are very complicated, making them inferior in cost and effectiveness. The authors overcame those drawbacks by using a precast form concrete caisson that has half-precast members and a reinforced concrete composite structure. The caisson is made of H-steel and comprises a high-durability precast form and an RC precast form, which are filled with super-plasticized concrete. In July 1999, we produced a precast form caisson measuring 14m long, 12m wide and 11m high in Tomakomai Port, to verify the method's effectiveness and economic feasibility.
