Hyperbolic Paraboloids and Northwest Modernism
Thin-shell construction was a signature of the late modernist movement in architecture. Light and efficient, this construction type was embraced by architects and engineers alike, as a means to minimize construction materials and increase structural performance while obtaining a dramatic aesthetic affect. Specifically, the use of the hyperbolic paraboloid – a geometric surface generated from the rotation of straight lines – was widespread and became a defining shape of post-war modernism. This type of construction was widely used in the Pacific Northwest between 1950 and 1975 – becoming emblematic of the spirit and aspirations of the region during a significant period of economic growth.
As a hybrid creation of modern architecture and structural engineering in the post-war era, hyperbolic paraboloid structures required intense collaboration across disciplinary divisions, and its design blurred the line between the two fields. Structure and form were united in these unique built works – a hallmark of Northwest Modernism.
Figure 1: Hyperbolic Paraboloid Surface
The hyperbolic paraboloid is a doubly curved geometric shape created from the rotation of only straight lines – generating a ‘twist’ of an otherwise flat plane. This shape, while providing a visual ‘warping’ and expression lacking in pre-war architecture, was also found to be an efficient, load-bearing structural shape when properly arranged. The warping of the shape reduced its tendency to buckle in compression (as a flat plane would), and simple prestressing cables were able to handle any tension forces that developed. As a result, these structures attained remarkable thinness over long spans – for example, spans of over 80 feet, with thicknesses of no more than 1.5 inches. The duality of this form, operating in both technical and aesthetic realms, blurred the lines between architecture and engineering in the creation of buildings, and forged strong connections between the professions on these projects.
The hyperbolic paraboloid, in various different combinations, was incorporated into the designs of notable Northwest architects like Fred Bassetti, Paul Thiry, Perry Johanson, Paul Kirk and Floyd Naramore who celebrated its expressive characteristics and versatility. In addition, engineers like John Skilling and Jack Christiansen contributed greatly to the physical geometry of the building – employing design driven by engineering efficiency and economy in creating the primary structure of the buildings. In fact Christiansen, as an engineer with strong business aspirations, contributed the most to the dissemination of this structural-type in the region. With his business partner, Christiansen developed a reusable formwork system that enabled an economical, rapid construction of hyperbolic paraboloid forms, and between 1956 and 1974, Christiansen realized over 43 independent hyperbolic paraboloid buildings – ranging from gas stations to churches, warehouses and assembly halls. His most famous accomplishment was the design of the Kingdome (completed in 1975) – the largest concrete dome in the world, until its demolition.
Figure 2: Key Arena, Seattle
Figure 3: Ingraham High School Audtiorium, Seattle
Figure 4: Shannon & Wilson Office Building, Seattle
Figure 5: Mercer Island Beach Club
More so than in other regions of the United States, the hyperbolic paraboloid was widely in the Pacific Northwest from the 1960s to the early 1980s. The most recognizable hyperbolic paraboloid form in Seattle is that of the Key Arena, formerly the Coliseum for the 1962 Century 21 World’s Fair, designed by Paul Thiry. Notable projects include the Mercer Island theater hall (1959), the multipurpose room at Ingraham High School (1960), as well as smaller work like the Shannon and Wilson office building in Seattle (1959), Moses Lake Public Library (1964) and the Mercer Island Beach Club (1963). The Grant County Grandstand (Moses Lake) and Pioneer Middle School (Wenatchee) use the inverted hyperbolic paraboloids in an inverted umbrella form – both freestanding and in combination – and directly recall the similar contemporary design work of Felix Candela.
Figure 6: Moses Lake Public Library
Figure 7: Grant County Grandstand
Figure 8: Pioneer Middle School, Wenatchee
Along with contributions from designers in Oregon, Idaho and Montana, the hyperbolic paraboloid during this time transitioned from an object of high design to a vernacular form – one enveloped into the everyday routines of people across the Pacific Northwest, becoming subconsciously associated with the conditions of the 1950s/60s/70s world. Christiansen estimated that by 1982, over 1.5 million square feet of buildings had been constructed using hyperbolic paraboloid forms in Washington State alone.
Now these structures are facing new challenges. While their engineering principles remain constant with their form, a lack of maintenance, changing economic demands and evolving construction trends are threatening these structures. Often too ‘young’ to be deemed historic, their efficiency of construction (thin concrete or wood) makes them easy targets for demolition, without regard for their history or unique design features. Activism through organizations like do.co.mo.mo. wewa (Documentation and Conservation of the Modern Movement, Western Washington) has assisted in raising the profile of modern architectural history, but this structural-type commonly does not gain substantial notice.
Hyperbolic paraboloid structures stand as both a signature element of the regions’ built environment and a testament to the collaboration between architects and engineers. Yet only increased appreciation and awareness can ensure these structures will be around for another 50 years.
Tyler S. Sprague is a doctoral candidate in the College of Built Environments at the University of Washington. Research into these structures is currently funded by the Center for the Study of the Pacific Northwest and the Marion Dean Ross Chapter of the Society of Architectural Historians.