Designed by Nikken Sekkei, the W350 plan is a technology research development project for constructing a 350-meter tall wooden super high-rise building by 2041—a year coinciding with the 350th anniversary of Sumitomo Forestry Co., Ltd.
The mixed-use development would call for more than 6.5 million cubic feet of wood and cost about $5.6 billion USD. It features a 9:1 ratio of wood to steel to meet Tokyo’s stringent seismic requirements.
The project develops a roadmap for super high-rise timber buildings and the future vision of eco-wooden cities.
By constructing office-based, multi-use buildings that have 70 stories above ground with GFA of 455,000 m2, using a huge amount of timber of 185,000 m3, this project envisions connecting forests and cities and solving the problems in both forests and cities.
At the present stage, the main objective is to identify the issues related to wood, such as building structural systems, construction methods, materials used, and resource development to create this roadmap for future technologies to be researched and developed.
For the purpose of conducting a concrete technical verification, the construction site is set at Marunouchi, Chiyoda-ku, Tokyo, and the scale of the building is set as a supertall building with 70 stories above ground and around 350 meters high.
The plan shape is set at 80m x 80, and the column span is set with a 10m grid.
The internal frame is made of wood only; meanwhile, a hybrid frame is adopted in the outer frame so as to utilize the characteristics of materials, i.e. the compressive force is resisted by wood and steel, and the tensile force is resisted by steel.
In this way, the necessary stiffness and strength can be maintained against the lateral force induced by strong wind or earthquake.
In general, a supertall building has a “center core;” however, in this project, the architects provided core stiffness within the “timber interface” areas, which are allocated like balconies around the building.
From the viewpoint of the traveling length of an escape route to the outside of the building envelope, this layout provides a safer route.
In addition to the escape route, the “timber interface” can provide a continuous interior and exterior environment filled with fresh air, abundant nature, and sunlight, which are difficult to provide in general high-rise design.
And the central void that optimizes the internal space provides natural ventilation and lighting and creates living space.
With the aim to create environmentally-friendly, timber-utilizing cities that are transformed into forests through wooden high-rise buildings, this project will contribute to people, society, and the global environment through futuristic technologies including the development of building methods, eco-friendly technologies, and trees as resources and building materials.
Sumitomo Forestry is responsible for the project concept and lumber engineering, and Nikken Sekkei is responsible for the architectural design and structural design of the emblematic 350-meter high wooden building.
Project: The W350 plan
Designers: Nikken Sekkei Ltd.
Design Team: Hiroaki Harada, Takashi Fukushima, Tatsuya Hatori, and Hajine Aoyagi
Client: Sumitomo Forestry Co., Ltd.