Tokyo Dome - the first roofed baseball stadium in Japan

Background Membrane structure is an alternative to conventional reinforced concrete shells and steel frame trusses. The roof is constructed of membrane material and cables, and is a large space structure that exceeds the concepts of conventional architecture. In the United States at least 10 large-scale roofs have been constructed using this method.

Overview In pursuit of the dream of being able to see a baseball even when it is raining, Takenaka was the key player in the realization of Tokyo Dome, the "Big Egg," as the first large-scale membrane structure in Japan. The development of related technologies was indispensable to the success of this project. These technologies included: structure, materials, disaster prevention, wind resistance, air-conditioning, lighting, acoustics, snow melting, maintenance and conservation. There are two types of membrane structures. They are the "air-support type" in which the membrane is made to swell by increasing the air pressure indoors by 0.3 percent relative to the air pressure outside, and the "suspension membrane type" in which reinforcement is incorporated into the membrane, in much the same way as an umbrella.

Features 1. Light spaces without beams or trusses have wide-ranging applications, including sporting facilities such as sporting stadiums, gymnasiums, skating rinks and swimming pools, as well as shopping malls, multipurpose venues, transport terminals, zoos and botanical gardens, and storage facilities and factories. 2. We succeeded in reducing the construction costs of large structure roofs which are said to be square in proportion to the span. 3. This membrane structure has the economic benefit that lighting is not required in the daytime.

Membrane materials

Roof surface

Air pressure

When snow falls

Management system

Example of membrane structure

Tokyo Dome

Tokyo City (Completed in 1988)
Design: Nikken Sekkei Ltd., Takenaka Corporation.
Total floor space: 115,221 m²
Structure: Membrane, 2 floors below ground, 6 floors above ground

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