The Illinois

The Illinois
General information
Status	Never built
Type	hotel, office, residential
Location	Chicago, Illinois, USA
Height
Antenna spire	5,680 ft (1,730 m)
Roof	5,280 ft (1,610 m)
Technical details
Floor count	528
Floor area	18.46 million ft2 (1.71 million m2)
Elevators	76

Not to be confused with Kingdom Tower, previously known as Mile-High Tower

The Mile High Illinois, Illinois Sky-City, or simply The Illinois was a proposed skyscraper that would have been 1 mile (1,600 m) high, envisioned by Frank Lloyd Wright in 1956. The design, intended to be built in Chicago, would have included 528 stories, with a gross area of 18,460,000 square feet (1,715,000 m²). Had it been built, it would have been the tallest building in the world by far, being more than four times the height of the then tallest building in the world, the Empire State Building, and it would be nearly twice as tall as the world's current tallest building, the Burj Khalifa.

The building is one of the semi-serious visionary buildings meant to be an alternative to the increasing urban sprawl occurring in most cities. None of these has ever been viewed as financially feasible.

The design of the Burj Khalifa, the current tallest building in the world, is said to have been inspired by that of The Illinois.

Technical feasibility

Wright believed that it would have been technically possible to construct such a building even at the time it was proposed. At the time, the tallest skyscraper in the world was New York's Empire State Building, at less than a quarter the height suggested for the Illinois. It probably would have been possible to erect a self-supporting steel structure of the required height, but there are a number of problems which occur when a building is that tall.

The material used for towers at the time, steel, is quite flexible. This causes the tower to sway substantially in the wind, causing discomfort for occupants of the higher floors. Though Wright acknowledged this problem in his original proposal, he claimed the tripod design of this tower (similar to that of the CN Tower, which was not designed until a decade after Wright's death) combined with its tensioned steel frame and the integral character of its structural components would counteract any oscillation. It is also possible this could have been solved by placing a tuned mass damper somewhere within the tower as was done in the Citigroup Center and Taipei 101, although this design innovation was not well known until decades later.

Also, the late 1990s and early 2000s have seen substantial increases in the load-bearing strength of concrete, making it a possibility to build entirely in this less flexible material.

The space needed to service the elevators (needed to reach the higher levels) would occupy all of the space available on the upper floors, thus defeating the purpose of the building's height. This was complicated by Wright's slender design. This problem has also been addressed in smaller buildings, such as in the Taipei 101, by using double-deck elevators. In the World Trade Center, the building was divided into three sectors, each with its own sky-lobby, where occupants changed between large express elevators and smaller local elevators. However, even with both of these measures implemented, the problem would still exist. Wright's solution was five-story elevators, running on ratchet interfaces located on the outside of the building (presumably on the unseen side in his painting) to conserve building space.

Another concern was fire safety. The need for emergency stairwells would bind much of the available space in the upper floors in a similar fashion as the elevators.

Albeit at a smaller scale, the same problem as with the elevators is encountered with water and sewage.

See also

• List of tallest buildings and structures in the world
• Burj Khalifa
• Kingdom Tower
• Chicago Spire
• Arcology

External links

• Wright information page
• Italian page on the Illinois
• Qualcomm Stadium renovation in San Diego may include Illinois-like supertall
• Details several tall building designs, including The Illinois
• Drawing of The Illinois at Skyscraperpage.com
• A Drawing of The Illinois by Frank Lloyd Wright