SR 520 Portage Bay Bridge Replacement • Seattle, WA

SR 520 / I-5 to Montlake I/C and Portage Bay Bridge Replacement (D/B), Seattle, WA

This design-build project will replace the existing Portage Bay Bridge 520/3, with two new parallel variable depth segmental box girder bridges across Portage Bay, the existing SR 520 eastbound off-ramp structure to Montlake Boulevard East, the existing 10th Ave E and Delmar E undercrossings with a new landscaped Roanoke Lid Bridge. Biggs Cardosa is responsible for the PS&E design of Roanoke Lid structure with a regional park/trails on the top) with associated 30+ westside walls, and independent structural analysis of two parallel SR 520 segmental bridges over the scenic Portage Bay near the University of Washington’s Seattle campus. This final west connection of State Route 520 when completed will be the largest projects of Washington State Department of Transportation.

SR 520 Portage Bay Bridge Replacement