|Antenna spire||527 m (1,730)|
The Willis Tower is a skyscraper in Chicago, Illinois. Sears, Roebuck and Company paid for the building to be built in August 1970. It was called the Sears Tower until 2009. The building was finished in 1974. The Willis Tower was the tallest building in the world from 1974 to 1996. It has 108 levels, and from the ground to the roof it is 442 m (1,451 ft) tall. The tower was designed by Fazlur Khan and Bruce Graham.
Before the Willis Tower was completed, the tallest building in the world was the World Trade Center. In 1996, the Petronas Twin Towers in Kuala Lumpur, Malaysia became the world's tallest buildings. The Willis Tower is still the tallest building in the world from ground to pinnacle because it has two television antennas on top of it.
Sears executives decided that the space they would immediately occupy should be efficiently designed to house their Merchandise Group. But floor space for future growth would be rented out to smaller firms and businesses until Sears could retake it. Therefore, those floor areas had to be designed to a smaller plate, with a high window-space to floor-space ratio, to be attractive and marketable to prospective lessees. Smaller floorplates required a taller structure to yield sufficient square footage. Skidmore architects proposed a tower with large 55,000-square-foot (5,000 m²) floors in the lower part of the building, and gradually tapered areas of floorplates in a series of setbacks, which would give the Sears Tower its distinctive look. The design was inspired by an advertisement for a package of cigarettes.
From the ground to the top of the taller antenna is 527 m (1,730 ft). The building leans about 4 inches (10 cm) towards the west due to its slightly asymmetrical design, placing unequal loads on its foundation. The Willis Tower is the tallest skyscraper in North America.
- "Willis Tower - The Skyscraper Center". Council on Tall Buildings and Urban Habitat. http://skyscrapercenter.com/chicago/willis-tower/.
- The History Channel; Modern Marvels (series); episode: The Sears Tower
Other pages [change]
Other websites [change]
|Wikimedia Commons has media related to: Willis Tower|
- Official website
- Chicago Skydeck website
- Emporis.com - Willis Tower
- SkycraperPage.com – Willis Tower
- A view from 103rd floor of the tower