To watch an animation of the assembly and erection of this structure, click here.

This spatial structure is made of square-on-square offset flat double-layer grid, which was designed by the architect Kenzo Tange for the Symbol Zone of the Expo 70 Festival Plaza in Suita, Osaka, Japan. The project engineers were Fukuda and Kamiya. All the members and nodes were specially designed and constructed for this project during 1969-70.

The structure was built using the Lift Slab Method as it was assembled on the ground and lifted in-place using pneumatic jacks at the locations of the six large supporting columns. The roof was lifted in 3.15" increments at an average rate of 79 inches per day.

The total plan dimensions were 956'-8" by 354'-4". The flat double-layer grid had a module size of 35'-5" by 35'-5" with a depth of 25'-0". The supporting columns were placed at 248' on centers in the transverse direction and 354'-4" in the longitudinal direction, resulting in a structure having overhangs of 124'-0" on each side in the longitudinal and 53'-2" in the transverse directions. The six support structures consisted of the members of the spatial structure placed around a 5'-11" tubular central column.

One of the main spans of the structure included a 177'-2" diameter circular opening. The exhibition spaces were located within the roof structure. This very large-scale spatial structure consisted of 20" diameter round steel tubes for the top and bottom layers and 14" diameter tubes for the bracing members with varying wall thicknesses from 0.31" to 1.18" depending on the forces to be resisted. The members were welded to the conical cast steel hollow spherical nodes with diameters varying from 31.5" to 39.4".

A translucent roof deck made of inflated pillows fitted into the top layer grid was used. Two hundred and forty three polyester film membrane cushions 32'-6" by 32'-6" were used. The upper and lower skins were made of 6 layers of polyester with each layer running perpendicular to the adjacent layer. A special ultraviolet-resistant film was used for the outer layer of the pillows.
The structure was later dis-assembled.