The tunnel that Bertha built is scheduled to open to Seattle drivers this fall, based on an updated schedule from contractor STP.
The new opening is sooner than originally estimated by STP. At one time, officials thought the project would be finished in 2015 but the project fell behind due to Bertha the Tunnel Boring Machine's breakdown.
A significant amount of work remains between now and tunnel opening. Crews must complete construction of the roadway within the tunnel, and finish installing many interconnected systems that will be required to operate the tunnel. They also must complete a series of thorough tests and certification by the Seattle Fire Department to ensure the systems are working properly. This includes testing approximately 5,000 individual components and nearly 90 tunnel systems.
As STP continues their work, construction of final ramp and highway connections to the tunnel is set to begin. The SR 99 Connections Project will build the final connections between the existing highway and the tunnel. Scarsella Bros., Inc. is the contractor for this work, which will be performed under a $22.6 million contract awarded by WSDOT last month.
WSDOT says after the tunnel opens, crews will begin demolishing the old Alaskan Way Viaduct, decommissioning the Battery Street Tunnel, an reconnecting surface streets across Aurora Avenue North.
The agency said last August the three projects were bundled together to shave off about one year of cumulative construction time. The original plans were to make each project a stand-alone job with each contract to be awarded and overseen separately.
Instead, WSDOT will award the bundle to as yet unnamed contractor. The contract will entail:
- Demolishing the Alaskan Way Viaduct (estimated completion: fall 2019).
- Decommissioning the Battery Street Tunnel (estimated completion: mid-2020).
- Rebuilding Aurora Avenue North near the SR 99 tunnel’s north portal (estimated completion: mid-2020)
The contractor awarded the project will determine how the viaduct will be demolished within parameters set in the contract. WSDOT plans to select a contractor in late spring, and will share the demolition plan and schedule after the contractor is chosen.
The Viaduct Demolition page has more information about the elements of this work. WSDOT says, "We won’t know the means and methods of the work until after we’ve chosen a contractor, but we do know that the timeline for delivering all three elements will be shorter thanks to the humble magic of contracts."