Seismic Design of Sports Arena for Tokyo Olympic 2020 Using Energy-Dissipation Devices

This facility was used for the Tokyo 2020 Olympic and Paralympic Games. It is a multi-purpose arena with up to 11,000 seats, and the roof covers the large space of the auditorium and stadium column-free. In this paper, the structural design of the main arena is introduced. The roof frame is structured by steel pipe trusses with simple planar trusses as a basic unit. Each planar truss is designed in accordance with the bending moment distribution which occurs in the various span each frame has. By arranging these planar trusses with various shapes, a free roof form is possible to be realized rationally. Oil dampers are installed at the joint of the truss girder and the truss columns, giving the damping effect of earthquake and wind. The dampers are effective at reducing vibrations not only horizontally but also vertically. With respect to unexpected earthquakes, this design is based on the concept of fail-safe, so as to ensure safety. Based on the idea above, large space structure with higher safety is realized using a simple structural system.