what we do

Bridges & Structures

Designing bridges and structures that work

Bridges and structures provide critical connections for our transportation system. Parametrix’s structural engineers develop solutions that balance technology and complex site considerations to reduce cost, construction time, and impacts to the human and natural environment. We help clients locate, survey, design, inspect, and maintain bridges, highway structures, and other unique structures.

SR 520 West Connection Bridge | Parametrix
SR 520 West Connection Bridge 
Seattle, Washington
Client: WSDOT

Partner: HDR Engineering

As part of the SR 520 Floating Bridge Replacement and HOV program, a new 1,334-foot-long West Connection Bridge had to be constructed to connect to the west end of the new floating bridge across Lake Washington. Parametrix designed the 507-foot-long, 5-span portion that transitions from the existing approach. The complex geometrics of the drilled-shaft supported widening required a comprehensive seismic analysis to ensure that the prestressed girder structure would meet all interim and future loading conditions, and that the new structure would not damage the existing structure in a seismic event. On-time delivery was critical for the project since delay of this project would have a direct impact to completion and opening of the floating bridge. Parametrix was also part of the design team for the future westbound approach for the corridor.

Project Website:  https://www.wsdot.wa.gov/Projects/SR520Bridge/Projects.htm



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