I-5 Corridor Improvements
The Washington State Department of Transportation (WSDOT) has awarded Atkinson a design-build contract for I-5 Corridor Improvements from Steilacoom-DuPont Road to Thorne Lane in Lakewood, WA. Jacobs Engineering Group is the project engineer.
Atkinson’s project team will widen 5.25 miles of Interstate 5 to add a fourth general-purpose lane in each direction. Atkinson’s team will replace the existing Thorne Lane and Berkeley Street interchanges and build grade-separated crossings over the adjacent Sound Transit railroad. The team will also construct new auxiliary lanes along the interstate, reconstruct the Madigan Gate Access Control Point, raise the I-5 mainline grade to fill a sag at the Berkeley Interchange, and construct three intersection roundabouts. The scope of work also includes a high-performance median barrier, retaining walls, sound walls, security walls, drainage, signing, illumination, and intelligent transportation systems.
Atkinson developed several WSDOT-approved Alternate Technical Concepts to solve many project challenges in the original design, which improved freeway operational efficiency, freight mobility, and local street access, as well as minimized impacts to the traveling public during construction by eliminating almost all extended ramp closures.
Design is underway and construction is slated to begin in Fall 2018. Substantial completion is scheduled for summer 2021.