AKA: Seafirst Corporation, 5th Avenue Plaza Building, Downtown, Seattle, WA; Bank of America Plaza, Downtown, Seattle, WA

Structure Type: built works - commercial buildings - office buildings

Designers: 3D/International (3DI), Incorporated (firm); Skilling, Helle, Christiansen, and Robertson, Incorporated, Engineers (firm); John Valdemar Christiansen (structural engineer); Natalie de Blois (architect); Helge Joel Helle (structural engineer); Gerald D. Hines (developer); J. A. Jones (building contractor); Richard L. Kreutz (architect); Leslie Earl Robertson (engineer); John Bower Skilling (structural engineer)

Dates: constructed 1979-1981

42 stories, total floor area: 1,249,055 sq. ft.

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800 5th Avenue
Downtown, Seattle, WA 98104

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The Gerald D. Hines Interests of Houston, TX, and Seattle 1st National Bank acted as developers of the Seafirst 5th Avenue Plaza; Hines retained as architect the Houston-based architectural firm, 3D/International, Incorporated, Houston,TX, founded in 1953; Hines had a strong working record with them, having developed the 3D/International Office Tower (1978-1979), in Houston at about the same time. Natalie de Blois (b. 1921), was the lead designer. Richard L. Kreutz served as 3D's Project Manager. Seattle's renowned engineering firm of Skilling, Helle, Christiansen, Robertson, acted as the structural engineers and J.A. Jones served as the building contractor.

The Seafirst 5th Avenue Plaza was the largest private office building built in downtown Seattle, WA, during the 1960s-mid-1980s. According to King County Department of Assessment figures, this steel and reinforced concrete skyscraper contained 42 stories and 1,249,055 gross square feet, 914,733 net, and occupied a 61,440-square-feet (1.41-acre) site. Office space took up 1,014,896 gross square feet, with basement storage containing 33,038 square feet and an underground parking structure possessing 201,121 square feet. (See The King County Department of Assessments,Accessed 08/20/2014.) Working drawings for the 5th Avenue Plaza Building (Project #74210), including architectural, structural, electrical, plumbing, shop drawings, and were archived in the papers of Natalie de Blois, "Natalie de Blois Working drawings and students' studio work, 1965, 1979-1990," held at the University of Texas, Libraries, Alexander Architectural Archive, Accession #1991007. (SeeAccessed 02/16/2011.) Like most Modern office towers of the late 1970s, the exterior had fixed rows of ribbon windows, requiring the building's ventilation system to completely heat and cool the interior.