No. 417: A new floating dock to be installed not on the sea but on land (January 23, 2012)

Technology

Floating docks are resistant to tsunami, and they are installed on the sea and used for the anchorage of ferries. Mitsui Engineering and Shipbuilding developed the land version of a floating dock. It is a cavity concrete structure that floats almost without being submerged even if it is attacked by tsunami (tidal wave). When tsunami comes, the walls of the newly developed floating dock slant to the anticipated direction from which tsunami comes, and they pass off water. It can resist tunami with a velocity of about 10 m per second. Because it minimizes the damage caused by submergence, it can be used as the base on which emergency generators are installed, warehouses are built, and helicopters are stationed.

The newly developed land floating dock is a cavity concrete structure tied to the ground by chains and large piles. Because it puts together structures each of which is 10 m long and 2.5 m high, rubbles left after tsunami can be cleaned easily by detaching the structures. In the model experiment, the land floating dock tilts the 4 m high walls to let the tsunami’s water pressure go downward and floats by creating a water passage on the bottom. It is scheduled to be priced at 50-100 million yen per 10 m x 10 m, and the construction cost is about 500,000 yen per square meter. The term of works will be between 6 months to 12 months. The company will market it to domestic municipalities and Southeast Asian countries suffering from food damage.