AKA: Century 21 Exposition, Washington State Coliseum, Seattle, WA; KeyArena, Seattle Center, Seattle, WA

Structure Type: built works - exhibition buildings - exposition buildings; built works - performing arts structures - performing arts structures; built works - recreation areas and structures - arenas

Designers: Naramore, Bain, Brady, and Johanson, (NBBJ) (firm); PCL Construction Services, Incorporated, Building Contractor (firm); Skilling Ward Magnusson Barkshire, (SWMB), Incorporated, Engineers (firm); Thiry, Paul, FAIA, Architect (firm); Wright, Howard S., (HSW) Construction Company (firm); William James Bain Jr. (architect); William James Bain Sr. (architect); Arthur J. Barkshire (structural engineer); Clifton J. Brady (architect); Howard Burton (structural engineer); Perry Bertil Johanson (architect); Jon Magnusson (structural engineer); Floyd Archibald Naramore (architect); Paul Albert Thiry Sr. (architect); William D. Ward (structural engineer); Howard S. Wright (building contractor/developer)

Dates: constructed 1960-1962

total floor area: 130,000 sq. ft.

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400 1st Avenue North
Seattle, WA 98109

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Building History

Architect Paul Thiry designed this 130,000-square-foot pavilion to have a large clear span suitable for exhibits. The Official Guide Book to the Seattle World's Fair (p. 26-27) noted of the building's form: "In the shape of a hyperbolic paraboloid, it has no interior roof supports. Four massive concrete abutments support the building's roof, which is 110 feet or 11 stories high. The aluminum paneled roof is supported by steel compression trusses and nearly 6 miles of steel tension cables." It cost $4.5 million to build, and was paid for by the State of Washington, Department of Commerce and Economic Development.

Building Notes

The Washington State Coliseum occupied nearly 4 acres of land in what was the Warren Neighborhood of Lower Queen Anne. Thiry created a design composed of a 400-foot square, within which was a clear span of of several hundred feet. This was accomplished utilizing reinforced concrete edge beams that were post-tensioned. The aluminum roof panels were supported by galvanized wire cables held in tension. The Howard S. Wright Construction Company built the Coliseum. Tel: 206.684.7200 (2006).


After the 1962 World's Fair, the plan was to convert the Washington State Coliseum to an 18.500-seat sports arena and convention center. It functioned in this way largely unchanged until the early 1990s. The Coliseum underwent a $74 million alteration and enlargement in 1994-1995 to serve as the home of the Seattle Supersonics Basketball Team. NBBJ Architects supervised this renovation and enlargement. Cleveland, OH-based Key Bank entered into a naming rights agreement with the City of Seattle in 1995, resulting in the facility rechristening as the "Key Arena." By 2006, the Supersonics' ownership claimed that the Key Arena generated insufficient revenue to maintain the team, and other venues were studied to which to move the team. In 2008, the team was moved by its ownership group led by Clay Bennett to Oklahoma City, OK.

PCAD id: 5972

"Presents new opportunities", Architectural Record, 129: 4, 255, 04/1961. "The Fair Becomes Seattle Center", Architectural Record, 133: 2, 32-2 - 32-3, 02/1963. Enlow, Clair, "It's Time to Worry about the Future of KeyArena", Daily Journal of Commerce, 2012-10-24. "Washington State Coliseum", Official Guide Book Seattle World 's Fair 1962, 26-27, 1962. Johns, Greg, "City still believes KeyArena can work", Seattle Post-Intelligencer, D2, 06/09/2007. Andriesen, David, "Will the puck stop here? A new arena would be more viable with an NHL team--if Seattle can get one", Seattle Post-Intelligencer, D1, D2, 02/01/2007. Brunner, Jim, "Key Arena bill 'really dead'", Seattle Times, B1-B2, 04/23/2009. "What's the rush with Key Arena plan?", Seattle Times, A13, 2017-02-14. Allen, Percy, "KeyArena keeps sponsor for 2 years", Seattle Times, B4, 10/07/2008. Brunner, Jim, Thomas, Ralph, "Investors float plans, work on legislators to keep NBA", Seattle Times, B1, B4, 2008-03-01. "Vote "no" on city sports initiative", Seattle Times, B6, 2006-10-18. Brodeur, Nicole, "No points for Sonics tax assist", Seattle Times, B1, 10/28/2009. Baker, Geoff, "In the Key Arena Debate, the Architects Have the Answers", Seattle Times, C2, 2017-04-17. Young, Bob, Brunner, Jim, "Why Sonics are leaving Seattle in 10 easy steps", Seattle Times, A1, A12, 11/14/2006. Evans, Jayda, "Seattle, Storm agree to lease", Seattle Times, C2, 01/13/2009. Calkins, Matt, "There Are Reasons to Doubt Key Arena Ideas Can Work", Seattle Times, C1, C4, 2017-01-26. Brunner, Jim, "Sonics argue team's economic impact nil", Seattle Times, B1, B4, 06/20/2008. "With the Sonics go TVs, office chairs and radios", Seattle Times, B6, 08/21/2008. Stone, Larry, "It's Time for Hansen, SODO Supporters to Face Reality", Seattle Times, C1, C4, 2017-06-02. Hasegawa, Robert, "City's court battle: Millions. Fans owning the Sonics: Priceless.", Seattle Times, B9, 07/02/2008. "Century 21 Revisited: A World Fair Enters the Construction Phase", Western Architect and Engineer, 221: 6, 22-26, 06/1961.