Information Bulletin No.36

"Megafloats" to be Used in Future Offshore Airports?

September 8, 1995

The possibility of using massive buoyant platforms termed "megafloats" in the construction of offshore airports is now under study.

Research into the concept of "floating airports" is generating enthusiasm among those involved in planning tomorrow's airports, many of which will be likely candidates for offshore sites due to noise and other considerations--a fact underscored in a report recently issued by an advisory group to the minister of transport.

In its midterm report on the Seventh Five-Year Airport Rationalization Plan (for the years 1996-2000), the Airport Council asserted that an offshore location was the "premise" for the construction of a third airport serving the Tokyo metropolitan area, supplementing the existing facilities at Narita and Haneda.

The megafloat concept calls for anchoring offshore buoyant structures resembling giant ships and using them as platforms for the construction of airports, waste disposal sites, recreational centers, or other space-consuming facilities. Proponents cite a number of advantages: Megafloats are earthquake resistant, can be built quickly, have a minimal environmental impact, and are cheap relative to the cost of reclaiming deeply submerged and thus unstable land.

With the backing of the Ministry of Transport 17 ship- building and steel companies established a research consortium in April to begin exploring the possibilities of megafloat technology. The consortium plans to invest 7.5 billion yen in order to carry out a full-scale megafloat demonstration running through fiscal 1997.

In the first round, scheduled for November, four buoyant structures made of steel (100 meters long, 20 meters wide, 2 meters deep) will be launched into Tokyo Bay from Yokosuka, Kanagawa Prefecture, and consequently welded together to form a single unit. Five more structures will be added in this manner in the summer of 1996, and in-depth studies will be conducted to determine the resulting platform's stability, the extent to which it rusts, and its impact on marine ecology.

Numerous questions must be answered before megafloats can be used to build a large-scale airport. These include how the steel in the platforms will affect air traffic control and aircraft instruments and how slight rocking of floating runways will complicate take-offs and landings. Nevertheless, the members of the research alliance are confident that megafloats represent an approach to construction that is extremely suitable for an island country such as Japan and are pushing ahead with their efforts to develop the concept.

(The above article, edited by Japan Echo Inc., is based on domestic Japanese news sources. It is offered for reference purposes and does not necessarily represent the policy or views of the Japanese Government.)