Kohn Pedersen Fox Associates and Leslie E. Robertson Associates have proposed a master plan for a new city in Tokyo Bay, a key feature of which is a mile-high (1,609-m) residential skyscraper.
One of the premises for the master plan, entitled “Next Tokyo 2045: A Mile-High Tower Rooted in Intersecting Ecologies” is the recognition that Tokyo faces a city-wide risk from rising sea levels, as well as seismic and typhoon risk. Given this, the authors argue that a strategy is needed that offers protection to the low-elevation coastal zones surrounding Tokyo Bay.
Their solution is the construction of an archipelago of reclaimed land to create a new district that would stretch 14 kilometers across Tokyo Bay between Kawasaki in Kanagawa prefecture and the shoreline of Kisarazu in Chiba prefecture (marked by the two red pins in the Google map below). Next Tokyo would create a protective border across the bay where multiple phases of land reclamation have already created a bottleneck in the bay.
Hexagonal infrastructure rings, ranging from 150 to 1,500 meters in width would be arrayed throughout the archipelago to disrupt the movement of ocean waves in multiple layers, while still accommodating shipping routes.
These infrastructure rings would be the foundations for clusters of recreational open spaces and for high-density development across the bay, a key element of which would be Sky Mile Tower, rising 1,609 meters above the bay. The master plans envisions that this reclaimed land could accommodate a half-million people who would move from currently at-risk coastal regions to this mega-city.
The authors point out that as Tokyo Bay is currently dominated by industrial use and shipping activity, the protection created by Next Tokyo makes it possible to introduce more mixed-use development and recreational activity into the upper portion of the bay.
Increasing transportation Links
Next Tokyo would also serve as a mid-bay transit hub connecting upper Tokyo Bay and Kanagawa and Chiba prefectures.
Currently, the Tokyo Bay Aqua Line, a bridge-tunnel combination, connects the city of Kawasaki in Kanagawa prefecture and the city of Kisarazu in Chiba prefecture, two of the most important industrial regions in the greater Tokyo area. The road was opened in December 1997 and reduced travel time from 90 to 15 minutes.
The “Next Tokyo 2045” proposal would reinforce this crucial route by building “tunnels to accommodate additional forms of mass transit between the shores, including regional rail lines and a new “Hyperloop” Maglev/vacuum-tube transport system, using technology currently being developed by Elon Musk.”
The primary station would service the Sky Mile Tower, four kilometers off the coast of Kisarazu and adjacent to the existing junction of the Aqua-Line bridge tunnel.
The master plan notes that the coastline of Tokyo has changed dramatically since the sixteenth century.
Currently, according to the study, almost 250 square miles of reclaimed land has been built up along the shores of the 1,300-square kilometer (502-square mile) bay.
“Next Tokyo 2045” seeks to minimize the use of reclaimed land in the bay. The Next Tokyo district in total would take up about 12.5 square kilometers, with artificial land accounting for only about twenty-five per cent of this area.
Instead, the hexagonal rings mentioned earlier in the article would provide the bulk of the infrastructure.
The smallest hexagonal rings would accommodate almost all of the high-density development, including the residential Sky Mile Tower and a range of secondary mixed-use towers.
The medium-sized rings would remain filled with water to protect the the high-density rings from wave action. They would also be used as fresh-water reservoirs and public beach harbors.
As mentioned above, the plan envisions that Next Tokyo will be home to 500,000 people.
The plan also sets forth ambitious renewable energy goals.
The authors write, “Energy will be generated on-site through a number of different mechanical systems, including the capture of kinetic energy from the trains running across the bay, the use of solar electricity from photovoltaic cells, and the use of wind power, harnessed through small-scale micro turbines integrated at high elevations in the mile-high tower.”
Urban farming on various scales would also be carried out in the district.
Sky Mile Tower
The centrepiece of Next Tokyo would be Sky Mile Tower, which the plan sees as “a leader in a new generation of megatall buildings with sustainability, efficiency, reliability, robustness, and safety as key features.”
Sky Mile Tower is meant to house 55,000 people in a vertical network of segmented residential communities linked together by multi-level sky lobbies and public amenities, including shopping, restaurants, hotels, gyms, libraries and clinics.
A mile-high tower comes with many engineering challenges. The primary concern of the structural engineering team was to reduce the movement and stresses caused by wind. The basic lateral force system that was proposed to deal with wind force was to place mega-bracing on the inner face of each of the building legs, combined with concrete shear walls at the sides.
Another engineering challenge is the collection and distribution of water in a mile-high vertical residential complex. The solution: cloud harvesting via the outer facade of the building!
Pumping the water directly from the ground would be very costly and time-consuming. To overcome this, an articulated facade around the tower’s legs would increase surface area as part of a strategy to allow for cloud harvesting as a water source.
The report notes that there is also the issue of moving 55,000 residents through the slotted and tapered form of a 1,600-m high structure. To address this, the elevator transport system runs both vertically and horizontally using ThyssenKrupp’s MULTI rope-free elevators.
As the proposal concludes: “The global population will likely continue to concentrate in urban areas, most of which are situated near major bodies of water…Next Tokyo presents a megatall building participating in the transformation of an existing megacity, allowing it to become more resilient to contextual change.”
Source: Next Tokyo 2045 Master Plan