With Bertha the tunnel-boring machine’s job complete and the drill dismantled, the tunnel that’s set to replace the Alaskan Way Viaduct is well underway. Eventually, the two-mile tunnel will carry cars from around the stadium district to Aurora Avenue North near Seattle Center.
Crews have been building the tunnel behind the drill’s path for quite some time, even before its run was completed. The tunnel’s corbels, or flat foundations that support the decks, are finished. As of last week, the southbound roadways are 85 percent complete. The northbound walls are largely done, and the southbound walls are almost halfway there.
To give an idea of the tunnel’s progress, the Washington State Department of Transportation (WSDOT) sent a drone down the tunnel’s 2-mile run from the north entrance to the south exit—and while it’s not quite the experience of driving through the tunnel, since it’s clearly still under construction, it helps give some idea of the tunnel’s place in the downtown landscape.
WSDOT notes that the lower deck is not yet visible in this video. Construction on that is scheduled to start next month.
Bertha officially finished the length of the two-mile tunnel, which will take cars past downtown along State Route 99, on April 4. That was a few years behind the original schedule, which estimated the tunnel would open in December 2015.
The tunnel project was a point of political contention, with many alternative transportation activists, including mayoral candidate Cary Moon, pushing for a surface-street option with transit accommodations.
The new roadway is set to open in early 2019. After it opens, the aging Alaskan Way Viaduct will come down.