Formerly: The Sears Tower
Formerly: The Sears Building
Designed by: Skidmore, Owings & Merrill
Renovated: 1985 by Skidmore, Owings and Merrill at a cost of $25,000,000
Renovated: 1994 by DeStefano and Partners
Maximum Height: 1,729 feet / 527 meters
Maximum width: 195 feet
Maximum length: 195 feet
Location: 233 South Wacker Drive, Chicago, United States
60% of readers like the Willis Tower.
he grandest tower in a city known for its great architecture, The Willis Tower has served for decades as a mighty symbol of architectural prowess and the triumph of engineering.
Just a few years after pioneering the trussed tube construction that allowed the 100-story John Hancock Center to be erected a couple of dozen blocks away, the same architects and engineers came up with another revolutionary construction method: the bundled tube design. The tower is essentially a series of nine tubes, bound together. Think of it as a pack of cigarettes with each tube rising higher than the rest. The shortest tubes are 50 stories, the second set rises to 66, the third set to 90, and the final to 110 stories. At the mechanical floors are extra trusses which act like belts wrapping around the building and helping counteract the forces of strong winds.
The tower was born out of the need of the Sears company to consolidate its offices. The original plan called for a much smaller tower, but the retailer was eventually convinced to concentrate its employees from seven other buildings into the lower portion of the building while leasing out the rest to other companies. It is fortunate that Sears listened to the architects and developers, because it is no understatement to call the result one of the most important buildings on the face of the Earth.
As Sears' financial fortunes changed, it moved out of this building and to a squat office part in the suburbs. By 2003 Sears had let the naming rights to the building expire. It wasn't until 2009 that the Willis Group consolidated a number of its regional offices into this building, and gained the naming rights in the process.
Shortly thereafter, as part of a larger renovation of the "Skydeck" observation level, four small outdoor observation pods were added to the 103rd floor. The transparent glass "Ledges" were designed by Skidmore, Owings & Merrill, the same architecture firm that designed the tower back in the 1970's. Each viewing platform extends out from the tower a little over four feet and is constructed from three layers of half-inch thick glass with a weight capacity of five tons -- two tons more than is called for in the city's building code. The ledges are retractable and placed on the west side of the building 1,353 feet above ground level.
- Architect: Bruce Graham
- Structural engineer: Fazlur R. Khan
- Bounding streets: Upper South Wacker Drive, Lower South Wacker Drive, West Jackson Boulevard, South Franklin Street, West Adams Street.
- West Quincy Street was removed to make way for this tower. The developers purchased it from the City of Chicago for $2,767,500.
- The original plan for this building was just 70-stories tall.
- Before construction, models of the this tower with the rest of the city were built and tested in a wind tunnel at the University of Western Ontario.
- The last steel beam put into place in the construction of this building on the 110th floor was signed by over 12,000 Chicagoans.
- The building, itself, does not have a tunes mass dampener, which is common on large skyscrapers. But both of the two large antenna masts has one of its own near the top.
- The building's exterior is black anodized aluminum. The windows are tinted bronze.
- According to the Chicago Sun-Times, in 2005 a deal was in the works for CDW to move to this building, which included naming rights. The deal fell apart because the building's owners didn't want the word "Discount" on the tower.
- Height to tip of west antenna: 1,729 feet
- Height to tip of east antenna: 1,709 feet
- Height to roof: 1,450 feet, seven inches
- Height to glass ledges: 1,353 feet
- Official stories: 110
- Missing floor: 109. The building owners count the roof as 109.
- Disputed floor: The mechanical penthouse for the elevators. Some buildings count this, some do not. Sears Tower does.
- Total floor space: 4,560,000 square feet
- Rentable floor space: 3,800,000 square feet
- Weight: 222,500 tons / 445,000,000 pounds
- Caissons: 114 in bedrock 65 feet underground
- Elevators: 104
- Double-decker elevators: 14
- Escalators: 15
- Observatory elevators speed: 18.2 miles per hour
- Windows: 16,100+
- Property size: 2.96 acres
- Parking spaces: 160
- Plumbing: 25+ miles
- Electrical: 1,500+ miles
- Elevator cables: 80+miles
- April 6, 1973: Two women were hit by pieces of falling wood that broke loose from construction work on the 108th floor.
- May 3, 1973: Topping out.
- May 3, 1973: This building became the tallest building in the world, a title it would retain for 25 years.
- May, 1973: This building opened to the public.
- 1974: Construction ended.
- 1974: The Sears Skydeck opened to the public.
- 1981: Dan Goodwin climbed the exterior of this building.
- 1989: This building was sold for $800,000,000 to AEW.
- 1992: Sears moved out of this building to the suburbs.
- 1997: This building was sold for $804,000,000 to TrizecHahn.
- 1999: Alain Robert climbed the exterior of this building.
- September 11, 2001: The Sears Skydeck was closed after terrorists attack the World Trade Center and the Pentagon.
- October 29, 2001: The Sears Skydeck reopened.
- 2003: Ownership of this building was transferred to MetLife.
- 2003: Sears' naming rights to this building expired. There was no company willing to buy the rights immediately, so the name remained Sears Tower.
- 2004: This building was sold to Joseph Moinian, Joseph Chetrit, and John Huston.
- January 15, 2004: The Chicago Tribune reported that the Sears Tower would be equipped with cellular repeaters. This was to help cell phone users who have a hard time making and receiving calls in the tower because of its structure, and the fact that cell phone users inside the building can be a thousand feet higher than the nearest cell phone tower.
- March 11, 2004: Jeffrey Feil and Joseph Chetrit purchased the Sears Tower for $835,000,000.00.
- September 25, 2005: An investigation by Emporis determined the actual correct height to the main roof of this building is 1450 feet, seven inches.
- 22 February, 2006: Rogue skyscraper climber Alain Robert tells Vancouver 24 Hrs that the Sears Tower was his favorite illegal climb.
- May 23, 2006: A group of seven people were arrested in Miami for allegedly plotting to launch a terrorist attack on this building.
- January 19, 2007: This building was sold for $385,000,000.
- February 1, 2008: Several women walking by this building were shocked by electrical currents from the sidewalk. The stray voltage leaked from the system which automatically de-ices the sidewalk when it snows (a common device for large buildings in cold climates). The system was turned off until it could be determined what the problem was.
- March 11, 2009: The Wall Street Journal reported that if insurance giant The Willis Group consolidates its offices in this building it would be renamed The Willis Tower.
- March 12, 2009: The Willis Group announced it will move nearly 500 employees to the Sears Tower and rename it Willis Tower. It did not pay extra for the naming rights.
- April 21, 2009: The Sears Tower signs on this building were temporarily covered by by Willis Tower banners as executives tried to figure out how many signs to hang, and where.
- May 1, 2009: A plan was announced to add a glass floored outdoor viewing gallery to the observation level.
- June 24, 2009: A plan was announced to give this building a $350,000,000 environmental facelift. The plan included the possibility wind turbines and greenery on the roofs, replacing all of the building's windows, and changes to the building's mechanical systems to make them more energy efficient. The goal was to reduce the building's energy use by 80%. However, earlier thoughts about painting the building silver were thrown out.
- July 1 2009: Based on new signage, this building became The Willis Tower. The Sears Skydeck was renamed Skydeck Chicago.
- July 2, 2009: The outdoor viewing platforms on the 103rd floor open to the public. Collectively they are called "The Ledge"
- July 16, 2009: In a ceremony, the building name is officially changed from Sears Tower to Willis Tower.
- Plans have been announced to replace the building's 16,000 single-pane windows.
- New gas boilers using fuel cell technology to generate electricity.
- Modernization of the building's elevators and escalators to reduce energy consumption by 40%.
- Recovering condensation and upgrading restroom facilities to reduce water use by 40%.
- Solar panels on the 90th floor roof to heat water for restrooms.
- Smart lighting systems that automatically dim when sunlight is available.
- Construction of a pocket park at Wacker and Adams.
- Possible installation of wind turbines and/or green roofs.
- The view is much better at the John Hancock Center, but c'mon -- you HAVE to go to the Skydeck at least once.
- Prepare to enter the building like you're at the airport. You will have to go through metal detectors.