SR 520, 148TH AVENUE NE INTERCHANGE
Redmond, Wash.
Merit Award
Sent by: Granite Construction Co.
OWNER: Washington State Department of Transportation (WSDOT)
LEADING DESIGN COMPANY: HNTB Corp.
GENERAL CONTRACTOR: Granite Construction Co.
A new direct access ramp from eastbound SR 520 brings traffic into the Overlake Village area of Redmond through a 130-foot-long tunnel that passes under 148th Avenue Northeast. The scope of the project also included two roundabouts and several new city streets: Northeast Hopper and Northeast Shen Streets and Lumiere Avenue.
This solution helps drivers avoid the busy 148th Avenue Northeast/Northeast 24th Street intersection and establishes a direct route to destinations along and beyond 152nd Avenue Northeast.
Technology played a critical role in this project, from GPS to CAD, Agtek and PlanGrid. These applications helped the team identify constructability challenges, propose solutions, and ensure that everyone in the field was up to date. Some of these solutions included moving and relocating stacks for a planned soldier stack wall to avoid conflict with an air guide and quickly redesigning noise walls when problems arose without affecting the schedule.
To minimize traffic impacts along 148th Avenue NE while constructing the 130-foot cut-and-cover tunnel, the contractor used 30-foot-deep shoring adjacent to live traffic, allowing crews to build the tunnel in two phases This process also required digging around and under existing utilities, including a gas line, to ensure there were no utility interruptions.
Crews placed more than 3,800 cubic meters of concrete over the duration of the project and completed the bypass 34 days ahead of schedule in December 2023.
