The purpose of this study was to reveal how difficult it was to realize large structures of reinforced concrete hyperbolic paraboloidal (H.P.) Shells in the earthquake-prone Japan of the 1950s. The analysis examined the design and construction of the Sunpu Kaikan, focusing on the roles of Kenzo Tange, Yoshikatsu Tsuboi, and the staff of their architectural laboratories. This study brings out the following four points.
First, the designs of the Hiroshima Children’s Library and Ehime Prefectural Culture Center in the early 1950s helped Kenzo Tange and Tsuboi gain six insights. These were: curves that can be expressed by simple mathematical formulas, methods to prevent shell deformation, the relationship between shell and supports, the cost for construction, construction information, and acoustics arrangement. Tange and Tsuboi made significant use of these insights while constructing the H.P. shell for the Sunpu Kaikan.
Second, while Tange and Tsuboi took keen interest in the shells created by overseas architects such as Saarinen, Stubbins, and Nervi, we found that they were trying to create shells that would match and surpass them. While Tsuboi has worked with general contractors to compile the “standard specifications for the construction of shell structures,” Aoki published a journal article outlining the shortcomings of the Sunpu Kaikan construction, similarly to Nervi. This attitude contributed greatly toward the subsequent development of large-scale architecture.
Third, while designing the Niigata City Gymnasium, Miyagawa accurately understood the issues with the reinforced concrete H.P. shell of the Shizuoka Convention Hall and thus, proposed a steel framed H.P. shell. We also found that Tsuboi highly admired the fact that the shell of the Niigata City Gymnasium was not damaged by the 1964 Niigata Earthquake.
Fourth, through the completion of the Shizuoka Convention Hall, Tange and Tsuboi were able to visualize the difficulties in construction, the construction costs, and the labor involved in the constructions of the huge H.P. shell. Their teams were aware of the limitations and the problems of reinforced concrete, and thus, decided to take on the challenge of designing a suspended roof structure for the Yoyogi National Gymnasium.
Tsuboi focused on creating a balance between a large span and cost, exploring new possibilities for the designing of spatial structures by drawing ideas from bridge-building techniques.
