Tokyo Sky Tree (東京スカイツリ) is a construction project started in July 2008 in Oshiage, Sumida-ku, Tokyo. Originally conceived as “New Tokyo Tower” (新東京タワ), it is a broadcasting, restaurant and observation tower with a maximum height of 634 meters. That height was chosen to reflect the word musashi, the name of the former province of Musashi (武蔵) that included parts of the modern-day Tokyo, Saitama and Kanagawa Prefectures: 6 (六 mu), 3 (三 sa), 4 (四 shi).
Sky Tree is the tallest structure in Japan, the world’s tallest free-standing tower (officially recognised by Guinness World Records on November 17, 2011), and the second-tallest construction after the Burj Khalifa in Dubai (at 830 meters). It was completed in February 2012; the grand opening took place on May 22, 2012.
The project was financed by a consortium of Tobu Railway, the national network NHK and five other terrestrial broadcasters. It is designed by Nikken Sekkai, and built by the contractor Obayashi Corp., with estimated construction costs amounting to 40 billion JPY.
The site area includes an eastern and western shopping mall and covers 36,900 square metres in total. Sky Tree’s structural system is made of reinforced concrete, steel-reinforced concrete and steel structures, the massive foundation system comprises cast-in-situ piles, reaching down 35 metres below ground, and in-ground continuous wall piles in nodes made of steel-reinforced concrete, reaching down 50 metres. To reduce vibrations in case of earthquakes, etc., Nissen Sekkei employed a Center Column Vibration Control system (柱制振システム, shimbashira-seishin) that are modelled on a five-story pagoda. According to Nissen Sekkei, this control system will reduce the response shear force by 40 per cent during an earthquake.
Hirotake Takanishi, PR manager for Tobu Tower Sky Tree, maintains that the anti-quake measures could reduce quake vibrations by 50 per cent. Simulations had proved that the Sky Tree would withstand an 8.0-magnitude earthquake, and could withstand even stronger ones, but it couldn’t be said what its upper limit was. The shimbashira (central column) is made of reinforced concrete that is structurally separate from the exterior steel truss. It acts as a counterweight when the tower sways. Engineers are confident because five-storied pagodas with shimbashira columns have never been toppled by earthquakes in Japan. Another essential design element is that the tower will gradually change in cross-section from triangular at the base to round at the 300-metre point, which will help it to withstand strong winds better.
Even before its grand opening, Tokyo Sky Tree has already turned into a major tourist attraction, and the formerly tranquil shitamachi neighbourhood of Azumabashi will undoubtedly benefit from the new infrastructure and the expected stream of visitors. A ride to the first observation deck (at 350 metres) will set an adult back 2,000 yen, to the second deck at 450 metres 3,000 yen.
Oshiage 1-chome, Sumida-Ward, Tokyo 131-0045 – 〒131-0045 東京都墨田区押上一丁目, halfway between Narihirabashi Station (Tobu Isesaki Line), soon to be renamed to “Tokyo Sky Tree Station”, and Oshiage Station (Asakusa Line).
- Tokyo Skytree Official Website
- Tokyo Sky Tree pictures
- Nikken Sekkei: Tokyo Sky Tree, design concept, structural technology, designers & engineers
- Center Core Control System, based on five-story pagodas, illustrated by PEDPA (in Japanese)
- Tokyo Skytree’s disappointing attendance so far: 6.19 million visitors (Japan Today)
Click the thumbnails to open a slideshow
1. Aerial view of Tokyo Sky Tree, 2. Tokyo Sky Tree as seen from Asakusa Bridge, December 2011, 3. Miyabi lighting design, 4. The observation platform at 350 meters, 5. Tokyo Sky Tree hidden in the clouds (around 400 metres) - as seen from the Arakawa, July 2010, 6. Center Column Vibration Control (柱制振システム) by Nikken Sekkai, 7. Tokyo Sky Tree seen from Takeshiba Pier, September 2011, 8. Tobu 100 Spacia in front of Tokyo Sky Tree, March 2011 (Photo: Tobu Corp.)