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January 25, 2016

Best in state: Gold award/Special judges award
Complexity
KPFF Consulting Engineers

Image courtesy of Gustafson Guthrie Nichol
KPFF was the prime consultant for UW’s Montlake Triangle project, which involved building a new land bridge and lowering a street by 19 feet.

Project: UW Montlake
Triangle and Rainier Vista Client: University of Washington

The Montlake Triangle area is one of the more congested multi-modal zones in the Puget Sound region — it’s the confluence of two arterials, a regional bike/hiking trail, and a destination hub to the University of Washington, Husky Stadium and the UW Medical Center.

The area experienced frequent accidents and near misses because the trail carrying more than 1,200 people per hour was too narrow, the intersecting points confusing and the road crossings hazardous. The UW Montlake Triangle and Rainier Vista Project created a seamless grade-separated multi-modal transportation hub while transforming the main gateway to the University of Washington.

KPFF provided a leading role in all aspects of the project, from planning and design through implementation.

KPFF overcame significant challenges, including:

• Restoring the historic view corridor to Mount Rainier, which required 19,000 cubic yards of fill to be added above a 30-year-old parking garage, with fill depths ranging from 18 inches to 10 feet.

• Achieving the signature hour-glass shape of the land bridge, which required a 3-D post-tensioning system that included a novel crossing configuration of external ducts that minimized the bridge depth by reducing the concrete weight of the structure.

• Lowering a city street by 19 feet for the land bridge, which resulted in exposing one side of an existing underground parking garage, requiring seismic retrofits within the garage.

• Resolving complex geometric constraints to achieve safe, accessible and efficient pathways.

• Working with stakeholders to overcome significant budget-to-program challenges that did not detract from the overall goals.

The design for the lower Rainier Vista integrates the previously isolated ground of the Montlake Triangle by lowering Northeast Pacific Place, installing the land bridge, and completely revising the Triangle land form as an extension of the pedestrian mall. By claiming the Montlake Triangle as part of the Rainier Vista axis, UW returns to original intentions for the Triangle to act both as a terminus of the axis and a threshold into the university.

KPFF’s design also called for demolition of an existing railroad bridge to make space for the new land bridge abutment, but KPFF avoided demolition of the bridge and saved costs by incorporating it into the soldier pile wall and using it to support excavation for the land bridge abutment. In addition to reducing demolition and soldier piles, this design allowed the bridge to be used as a temporary roadway for traffic that was diverted during the nearby roadway excavation.

John Palewicz, director of strategic projects at UW’s Capital Projects Office, said, “As our prime consultant, KPFF worked with the university, our landscape design firm and four transit agencies to deliver a project that packed a lot of program into a tight budget…We believe KPFF exceeded our expectations by providing the leadership, creativity, teamwork and technical prowess we needed from them to deliver this complex and iconic project.”





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