What I am thinking: historian and structural engineer Tyler Sprague

Tyler S. Sprague teaches courses in structural design & architectural history at the University of Washington in Seattle, USA.  He holds engineering degrees from the University of California, Berkeley and the University of Washington (UW) and worked professionally as a structural engineer before completing a Ph.D. in architectural history in the College of Built Environments at the UW. Sprague’s research investigates the intersection of architecture and structural engineering, both in Modern architecture and the present. His doctoral dissertation “Expressive Structure: The Life and Work of Matthew Nowicki” examines the designer of the first tension-hung roof in the United States (the Dorton Arena in Raleigh, NC, begun in 1950). He has also published on the rise of concrete skyscrapers in the Pacific Northwest, the structural engineers of the 1962 Seattle Worlds Fair, and the thin shell concrete structures designed by Jack Christiansen.

Book Cover  “Sculpture on a Grand Scale: Jack Christiansen’s Thin Shell Modernism (Courtesy UW Press)

Adriaenssens: Why did you write a book about Jack Christiansen? 

Tyler Sprague: I wrote this book because I felt Jack Christiansen had an important story within the history of architecture and engineering, and one that hadn’t been told before.  Christiansen was a prolific, American designer of thin shell concrete structures, and repeatedly blurred the line between architecture and structural engineering in his work.  He started his career in the mid 1950s, when thin shell concrete was a cutting-edge technique.  He not only made thin shell concrete economical in the Pacific Northwest (through a re-usable formwork system) but also used it to design extremely long-span structures like airplane hangars and stadia. The Seattle Kingdome was the apex of his career, spanning over 660’.  Christiansen continued to believe in thin shell concrete throughout his career, even as it fell out of favor in the 1970s and 1980s, but was thankfully able to live long enough to see a resurgence of interest in shells. Christiansen’s story as a creative engineer, form-giver, shell builder is important for student, engineers and academics.  He was both a part of the global network of shell designers (like Anton Tedesco, Felix Candela, Heinz Isler) and distinct as an American designer.



Grant County Fairgrounds Shells (Photo by Tyler Sprague)

SA: What was his design philosophy?

TS: Christiansen’s structures reflect his belief that a building’s form should be a unification of architecture, engineering and construction.  He stated: “Those structures which respond the most efficiently to the natural forces of gravity are those which prove to be least costly and most aesthetically satisfying.”  He often let the geometry of formwork – most often the cylindrical vault and the hyperbolic paraboloid – drive the overall form of his structures.  He always worked in collaboration with architects (like Naramore, Bain, Brady and Johanson (NBBJ) and Minoru Yamasaki) and builders.  This collaboration was vital to Christiansen’s success, and enabled him to build extensively around the Pacific Northwest.

Shells Form Inc (Courtesy Christiansen Family Archive)
KCIA Hangar Courtesy (MKA Archive)

SA: What was his favorite realized structure and why?

TS: The Seattle Kingdome is certainly Christiansen’s most iconic work, and one he described as his “symphony in concrete.”  Though somewhat controversial, the Kingdome was a building vital to the growth of Seattle, providing a venue for professional football, baseball, and soccer teams.  Christiansen’s ability to design the thin shell concrete Kingdome on an extremely tight budget, in the midst of an economic downturn, was a remarkable engineering feat of efficiency.  It is certainly Christiansen’s most significant work.

Kingdome under construction (Courtesy MKA Archive)


1608-4-5 Views of Seattle [with Kingdome]003
Kingdome when completed (Courtesy King County Archives)
But there are many other structures – Christiansen designed over 100! – that are more striking in their form.  His design for the Ingraham High School Auditorium (1958) with architects Naramore, Bain Brady & Johanson (NBBJ) is a stunning structure, composed of three, hyperbolic paraboloid segments.  Even though it has a strict ruling geometry, it seems to resemble a bird or airplane taking off.   Christiansen was a master at using geometry to create beautiful, evocative forms.

Ingraham High School (Courtesy MKA Archive)

SA:  How did the environment he lived in, influence him?

TS: Christiansen was born in Chicago, but moved to the Pacific Northwest early in his career and immediately fell in love with the outdoors.  He started climbing mountains in the Olympic and Cascade ranges on the weekends – at the same time as he was designing thin shell structures – and eventually became a prolific mountaineer.  His sketches of mountain peaks are fascinating to compare to his structural sketches.  Both activities show Christiansen’s adventurous spirit and monumental ambitions, linking the buildings he designed with natural forms and landscapes.

 SA:  What lessons can we learn from him today?

TS: Wow, so many.  Christiansen’s work reminds that architecture and engineering are really two sides of the same coin.  Though he was an engineer, he was interested in aesthetics, space and form all at once.  Christiansen’s career also tracks the history of thin shell concrete, showing its role as an exciting medium of modern architecture.  The contemporary relevance of Christiansen’s designs and strategies shows how past building techniques can still offer something to designers and students today.  On an individual level, Christiansen showed the importance of a well-rounded life where professional design work is balanced with broader interests.


SA:  Where can we buy your book?

Copies can be ordered through the UW Press: https://www.washington.edu/uwpress/search/books/SPRSCU.html

Or through Amazon.


I hope you enjoy.  Check it out!

Image behind text: Courtesy Seattle Public Schools



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