Market
SR 99 Tunnel
Alaska Way Viaduct Replacement Tunnel
Project Details
TUTOR PERINI AFFILIATES
Tutor Perini Civil
Design-Build Contractor
Contract Amount: $1.4 Billion
Electrical Subcontractor
Contract Amount: $122 Million
Mechanical Subcontractor
Contract Amount: $75 Million
TBM Recovery Subcontractor
Contract Amount: $13.6 Million
Drilled-Shaft Subcontractor
Contract Amount: $4.6 Million
OWNER
Washington State Department of Transportation
LOCATION
Seattle, WA
ARCHITECT
HNTB
SIZE
1.8 Miles
COMPLETION
2019
Project Description
The SR 99 Alaskan Way Viaduct is being replaced with an approximately two-mile-long double-deck tunnel underneath downtown Seattle. Replacing the viaduct with a tunnel allows the highway to remain open for much of construction, thus minimizing closures and impacts to traffic. Once the tunnel opens, the viaduct will be taken down to clear the way for new public space along Seattleās downtown waterfront.
Seattle Tunnel PartnersĀ was responsible for designing and building the SR 99 tunnel. In addition to boring the tunnel and building the highway within it, STPĀ is responsible for building highway ramps and other connections at the north and south ends of the tunnel. They are also constructing buildings at each tunnel portal to house lighting, ventilation and other systems needed to operate the tunnel.
āThis truly is a remarkable feat of engineering. We've had delays and thereās still work to be done, but the individuals working on this job should be proud of this accomplishment.āRoger Millar
Secretary
Washington State Department of Transportation
Photo Credits: WSDOT