West Sammamish River Bridge Replacement
Design Start: May 2015
Design Complete: Fall 2018
Construction Estimated Start: Spring 2019
The City began design of the new bridge in May 2015. Design will take approximately 3-1/2 years as the City secures the necessary permits, right of way, and prepares the plans and specifications. Construction is expected to begin in the Spring of 2019, pending availability of funding.
The West Sammamish River Bridge carries southbound traffic over the Sammamish River on 68th Ave NE. The bridge was constructed in the 1930s and nears the end of its life. Over the past year, the City has increased monitoring of the structure, and in March of 2014 Council-approved weight restrictions went into effect. The City has completed a scour analysis (underwater erosion of soil around the piers), geotechnical review, and a load limit study. The southbound bridge is currently load restricted until the bridge is replaced.
The project will replace the existing west bridge (southbound travel lanes) with a new structure. Work will also involve replacing the approaches to the bridge between NE 170th St and NE 175th St.
The City applied for grant funds to construct a new bridge. The cost estimate to build a new bridge, with enhanced pedestrian/bicycle facilities and improved pedestrian and bicycle facilities from NE 170th to NE 175th Street (on the bridge approaches), is approximately $20 million. To date the City has secured the necessary funding to design and construct the project.