The architectural form of Natural Ellipse is very much a product of its unique environment. Wedged into the most vibrant shopping and entertainment district in Tokyo, the building acknowledges the conflict between the desire for privacy and the need to connect with the lively surrounding neighborhood. The result is a mostly introverted structure with a few carefully placed openings to the outside, allowing the privacy necessary for domestic life.
The work of Masaki Endoh and Masahiro Ikeda–as with many other contemporary Japanese architects–derives significance from exploring the physical and metaphysical nature of walls. At the critical point where matter really matters, controlling the material boundary between internal and external spaces is one of architecture s most compelling pursuits. Interest lies not so much in the technology deployed, the nuts or the bolts (which will always remain key considerations),but more in how materials moderate light, regulate the environment, and how solid, void and niche can bring order to the ritual of everyday life. Endoh and Ikeda have a very provocative style, one that is very striking visually. The downfall of their design is its lack of any human element. They seem to have prioritized the form of the building and its meticulously clean aesthetic over the use of simple comforts such as bathroom walls. The resulting space is an extremely sterile, bare building that seems as if it was made as a sculpture rather than a habitable building.
The structure is composed of flat iron ribs cut by laser. This method, which is now quite common, offers better performance than folding for this type of profile, but is not commonly used in structural work. The envelope was built on site and is made of fiber-reinforced polymer sheet, there are thus no seams to speak of, which enhances the plastic quality of the skin. A composite material developed by space and military research, fiber-reinforced polymer offers many advantages in comparison to traditional materials such as metal or concrete. Apart from an excellent weight/solidity ratio and good resistance to corrosion and wear and tear, it is fire-safe. The use of this material in architectural projects remains limited for lack of knowledge concerning its long-term performances. What is more, differences in the mechanical properties of fiber-reinforced polymer and conventional construction materials also constitute a barrier restricting its exploitation in building and public works, even if industrial and university researchers are studying the question. To date, fiber-reinforced polymer sheets have mainly been used in construction to dress the under-sides of roofs; their use for a vertical surface is thus totally new for construction firms. One benefit of this material is its insulating quality, which eliminates the need for supplimental insulation in the wall cavities.
The structure of the building is an integral part of its architectural expression. Inside and out, the structure is clearly visible, its presence undeniable. The tight skin-like exterior is tight enough to expose the shape of the 24 elliptical steel rings that frame the exterior walls. On the interior, these elliptical rings are resolved as interior columns that run down the hollow donut-like circulation atrium. The steel joist that hold up the concrete floors are also expressed on every level. While the steel frame itself is not visible on the interior walls, the construction definitely eludes to the nature of the steel skeleton. Rather than employing a smooth, rounded plaster wall, the architects chose to utilize flat sheets of gypsum wall board, allowing the joints in the structure to be subtly referenced. Architecturally, the exposed structure combines with the austere lack of ornament to create a bare, modern aesthetic that is very popular in Japan.
The elliptical shapes act as the vertical members in this structural system, though their bent shape causes them to be less efficient than a straight column. The floor plates are especially important in this structure because they are designed to resist the outward thrust of the elliptical columns. The floor itself is made of concrete, which, being poor in tension, is not made to resist the lateral thrust. Therefore, a tension ring lining each floor plate, and the steel joists that radiate from the center provide the necessary lateral support for the columns. Though the exterior material, fiber-reinforced polymer, is fairly strong, it serves no structural function in regards to shear resistance in the columns. Instead, a lattice of steel bars are crossed, and attached to the elliptical rings by clevises, thus counteracting any shear forces and further reinforcing the columns laterally.
Name: Natural Ellipse House│Type: Residential│Architect: Masaki Endoh│Completed: 2002