New National Stadium | Zaha Hadid Architects

Architectural Vision
The New National Stadium of Japan is more than a large sports facility designed to the highest design specifications and functional requirements. It is a piece of the city’s fabric, and urban connector which enhances and modulates people moving through the site from different directions and points of access. The elevated ground connections govern the flow of people through the site, effectively carving the geometric forms of the building. The stadium roof defines an iconic silhouette that integrates gently within the cityscape around it. It is an intricate assembly of efficient long-spanning structural ribs which are spanned by a system of lightweight, translucent membranes. This unique structure is a lightweight solution, where the stadium elevation graciously touches the ground, defining a clear approach towards the stadium entrances. The interior of the stadium is also given a clearly identifiable identity through the strong roof structure that contrasts with the lightness of the translucent membrane tensile structures. The seating bowl has been optimised to suit both Rugby World Cup and Olympic events, with a permanent athletics track to be inserted within the stadium. The design of the bowl will bring spectators as close as possible to the athletics track and jumps, and will not compromise the viewing experience of spectators during football or rugby events. The seating bowl is adaptable, and has been designed to allow for the scale of the stadium to remain compact. Following the Olympics it is proposed that flexible areas of seating are adapted to enhance the commercial revenue that can be generated by the facility in legacy mode. The form of the stadium has been driven in response to the functional planning requirements of the stadium and responded closely to the volumetric constraints imposed on this building by the local planning authority requirements.

Design Inspirations
Cultural Resonance
The ZHA design was inspired by the tradition and advanced culture of Japan. The site is the site of the Tokyo 1964 Olympic Stadium and it is an appropriate place to build a new national stadium which aspires to create a building which exceeds mere function to become a symbol of Japanese renewal and long term optimism for the future. The basic components of stadium design are extrapolated to connect the stadium to its specific context of Gainen and beyond to Japanese culture as an expressive but efficient design. The design is derived from the articulation of structure and circulation where structure is required to create roof cover over long spans without columns and a lot of circulation is required to safely move 80,000 people in and out of the stadium. Proposed for practical reasons the primary structure of two keel arches have a similar intent in silhouette and symbolism to traditional Japanese landscape bridges so that the new stadium is based on a key motif from traditional Japanese landscape design and an appropriate addition to the sports landscape of the Gainen area.

Stadium Geometry
With the cross ties, nature is further embodied in the design where the expressed structure creates a distinctive flower petal geometry so familiar in nature and to the Japanese public who have a close affinity to nature and the passing of the seasons. The flower petal geometry of the roof is continued into the façade where the structure is not only expressed but inhabited. A series of diagonal stairways and elevated walkways are developed into the envelope of the stadium so that it functions as a stadium on event days and every other day it’s an extension of the pedestrian landscape of the Gainen area allowing extended walks and elevated views over Tokyo.

Materiality
All of these public walkways are lined with Japanese timber, giving a tactile familiarity to the stadium which ties it back to the fundamental material of the Japanese environment and experience. The majority of façade is broken down by the petal geometry and clad in Japanese timber louvers so that the overall effect at pedestrian level is a subtle interplay of Japanese timber cladding giving the experience to the visitor of a direct resonance to the tree lined landscape of Gainen and Japanese culture.

Craftsmanship and Innovative Technology
The majority of roof structure is provided by catenary beams which resonates with the innovation by Kenzo Tange with his catenary beams for the Yoyogi National Gymnasium. We aspired to make the new stadium connect visually and symbolically with this Japanese icon of optimism so that Tokyo 2020 leaves Tokyo with a stadium as well conceived and as beautiful as this gymnasium from Tokyo 1964. The roof is covered in translucent lightweight fabric. The roof allows daylight in, allowing good turf growth whilst allowing the spectators to experience the pleasure of daylight as they watch the events. At night, the stadium will glow and take on the appearance of a Japanese lantern. Together the arches, catenary beams and lightweight fabric combined to create an overall effect that represents the traditional craft and modernist innovation of Japan, to create a renewal of the Japanese spirit of optimism for the future based on the confidence of their past.