The Structural Engineers Foundation (SEFW) held its inaugural forum on October 6, 2011. Jon Magnusson was the keynote speaker and his “Behind the Scenes Stories of Seattle’s Latest Generation of Landmarks” was an engaging look at both real and proposed Seattle area projects. More than 450 people attended this public event held at Benaroya Hall in Seattle.
Many attendees enjoys the Forum's pre-function networking reception
Jon Magnusson's presentation covered multiple Seattle landmarks, like Experience Music Project
Jon Magnusson addresses the crowd
Jon’s presentation began by attempting to answer the question of what constitutes a “landmark” with a brief look into the history of such structures in Seattle. He shared stories of landmarks that were never built, including transportation projects such as a regional heavy-rail transit system and a series of north-south highways running through Seattle. Atlanta received the rail funds that were originally earmarked for Seattle and the demise of the latter project explains the dead-end SR-520 overpasses just north of the Arboretum.
Fortunately, many projects made it off the drawing boards and Jon recounted the engineering accomplishments of several, such as Safeco Field and CenturyLink Field. Both stadiums use protective systems in their respective arched roof structures. CenturyLink features friction pendulum bearings between the steel roof truss and the concrete support piers. The roof at Safeco Field relies on piston dampers to resist seismic loads while allowing thermal expansion. These dampers and adjacent hinge connection are clearly visible at the north end of the moveable roof structures.
Jon explained that tall buildings also frequently use dampers. In the case of Seattle’s tallest building, the Columbia Center, friction dampers were located parallel to the braced frame diagonals to control drift under wind loads. To accommodate the curved façade of this landmark building, a triangular floor framing grid system was used with concrete mega-columns located at each corner. It was important to maximize the gravity loads resting on these columns to resist overturning demands. To achieve this, selected columns were removed from the basement level, thereby forcing the braced frames to load the mega-columns in an arching action.
Two contemporary landmarks, the Seattle Central Library and Experience Music Project, have elicited strong reactions from fans and critics. The Frank Gehry-designed EMP was a pioneering example of both Integrated Project Delivery and of Building Information Modeling, with the latter technology a necessity to design and fabricate the structural steel framing. The Library, designed by Rem Koolhaas, features a book spiral in the upper floors to accommodate an ever-expanding book collection. Finite element analysis was used to design the structural steel exterior walls.
SEFW is very grateful for our Founding Partners, the local industry corporation that contributed to this first Foundation event. The donors were as follows: