Subscribe / Renew
|► Subscribe to our Free Weekly Newsletter|
|print email to a friend reprints add to mydjc|
October 6, 2022
A renovation effort focused on URM building safety is underway at the University of Washington. Recognizing the Seattle region’s risk of earthquake damage to the city’s vulnerable structures, the university is undertaking a multi-phased project to improve the seismic resilience of 25 unreinforced masonry (URM) buildings on campus, increasing time for occupants to safely exit structures in the event of an earthquake.
Currently, more than 1,100 URM buildings are located in Seattle, with thousands more across the state. The walls and parapets of these buildings are uniquely vulnerable to collapse in an earthquake due to the nature of their construction. Seismic retrofitting focuses on structurally absorbing energy, adding strength, and allowing buildings to move with forces rather than simply break apart. This includes connecting brick walls and parapets to roofs and floors to increase earthquake resilience and enable the preservation and continued use of these iconic structures.
AHEAD OF THE CURVE
The University of Washington, the city of Seattle Department of Construction and Inspection, and the Seattle Department of Neighborhoods (SDON) Landmarks have a shared interest in improving the structural integrity and preserving historic features of the campus buildings. UW is leading the way in the Pacific Northwest ahead of regulations for retrofitting URM buildings in the state. In 2018, Clark Construction began its partnership with the university to supports its goals. Since that time, Clark has helped UW renovate the parapets, facades, and unreinforced masonry of 11 campus buildings. Currently our design-build team, which includes Mithun and Degenkolb, is under its fourth phase of design and permitting.
Performing these structural upgrades while preserving the historic character of the buildings on campus is a delicate process. With expertise in seismic retrofits dating back to the 1994 Northridge Earthquake in California, Clark’s experience includes the award-winning upgrades to Los Angeles City Hall and renovations to 18 buildings in nine locations for Catholic Healthcare West.
For work on Eagleson Hall, a two-and-a-half-story Gothic structure on the Seattle campus that was constructed in 1923 and named a historic landmark by Seattle’s Landmark Preservation Board, planning was key. The building’s landmark status meant that any improvements required approval by the UW Design Review Board and SDON Board to ensure the exterior and interior historic fabric of the building was preserved.
To better visualize the proposed improvements, our team performed a high-definition laser scan of the building to document existing conditions and created a virtual model to show proposed changes. The use of this technology enabled a collaborative review of the planned renovations and the process by which our team would protect the historic structure.
Delivering these upgrades required precision in the field. During Eagleson Hall’s renovation, our team first installed two brace frames one located between the Great Hall of the original structure and the gym addition, and the second along the length of the building on Northeast 42nd Street. In addition, we bolted the floors of the building to the walls, careful to protect the architectural facade.
The roof load of the building’s Great Hall was then supported with structural trusses which carefully sandwich its original Gothic trusses, mirroring these architectural features while protecting the structure from damage. Because the existing structure had shifted over time, each truss was custom built to fit its unique location. The trusses were delicately hoisted into place from inside the building using specialty hoisting equipment with sufficient lifting capacity that was small enough to fit in the space. The effort successfully preserved the historic character of the landmark while delivering critical safety upgrades.
Although the scope of our work focused on seismic upgrades to UW’s campus buildings, the process has yielded additional benefits. Our team enhanced finishes in locations where work was performed, optimizing value for the university. In addition, the university requested that the team explore upgrading specific components of the HVAC and telecommunications systems, since MEP components needed to be temporarily removed or relocated to facilitate the installation of seismic components. Focusing on these areas of the building, we designed a solution that increased thermal comfort.
As this multi-phase project progresses, our design-build team continues to apply lessons learned from one university building to the next, streamlining design details and material selection to create significant efficiencies across multiple buildings.
Kyle Knapp is senior project manager of Clark Construction Group.