years has been to develop the innovative construction system which we call the “Sakan Shell Structure” (SSS).

We strove to develop this construction system so that it would be as simple as possible, since there is often a shortage of manpower for reconstruction immediately following disaster events. Also, the nature of this system would ideally promote a collaborative effort within the affected area and in neighbouring communities, which would increase the survival rate in the aftermath of a disaster.

The structure of the temporary housing is supported by the Shell structure, which is made of mortar. The dome-shaped basic unit is the shell structure with four legs. Temporary housing for one family would be composed of four or five basic modular units combined.

In the past two years we have studied the structure and construction system (including detail design) and in March 2007 we successfully built a full-scale basic unit on the grounds of the University of Shiga Prefecture, Japan.

For the second stage of this project we would like to study this housing system more efficient, practical and to be suitable for long term use. Throughout this process it is our intention to construct temporary housing with five connected modular domes.

The most important features of SSS are as follows:
1) an air-dome was used in place of framework.
2) it is made from fiber-reinforced mortar (without steel reinforcement).
3) it employs plastering techniques and materials delivered from Japanese tradition.

The benefits of these features are as follows:
1) The use of an air-dome for the construction of the shell structure, as opposed to conventional framework, produces the shelter easily. The dome shape of the shelter makes the walls and roof integral, thereby making it possible to construct a living space in one process. The air-dome framework only takes a few hours to set up and it would be taken off and reused for subsequent domes once the mortar has hardened. This characteristic makes SSS the most effective system for the rapid provision of emergency housing.

2) The shell structure (which is made of glass fiber-reinforced mortar) is a mere 15mm thick on top and 30 mm thick on the legs. This characteristic reduces both material and energy requirements, which are critical factors in emergency scenarios.

The structural integrity of the shell was measured by performing load tests with 1:3 scale models. The thickness of the shell was determined by the results of horizontal load tests and it was found that the structure has the capacity to withstand severe earthquakes, such as the Great Hanshin Awaji Earthquake in 1995.

3) Most of the conventional emergency shelters require skilled workers for their construction. However, the plasterer method employed here does not demand any special skills, provided there are a few people who are responsible for the construction process. Also, the required materials are widely available, which means that the process should not be disrupted by damage to transport infrastructure during the disaster.

Aims of next research and development:
1) develop the performance of fiber-reinforced mortar. Especially we intend to improve fast hardening ability, tensile strength, water-resistant performance of mortal.

2) develop the performance of shelter to keep comfortable interior environment. Especially we intend to improve finishing materials for exterior and interior of dome , opening system with menblane materials, for more comfortable living.

3) Throughout constructing 5 domed temporary housing, we would like establish much more practical construction system.