Months after Bertha the Seattle tunnel machine stopped churning beneath the city, work continues on the SR 99 tunnel that will eventually replace the aging Alaskan Way Viaduct.
A drone video shot in September and shared by the Washington State Department of Transportation on Friday offers viewers an end-to-end view of the tunnel.
The drone enters at the north end near the Space Needle — over the deep receiving pit where Bertha came to rest in April — and eventually exits two miles later at the south end of the city near the sports stadiums.
The video shows what will be the upper and lower roadways of the double-decker SR 99, and identifies locations of intersections and landmarks along the way which are above ground, such as the Pike Place Market.
The tunnel work is advancing from the south, so the footage captures more completed work as it moves in that direction. Corbels (foundations of the road and walls) are 100 percent complete, the top deck of the double deck road is more than 85 percent complete, according to WSDOT.
The agency also said that next month, Seattle Tunnel Partners expects to start bringing in prefabricated road panels (made in Tacoma) that will be assembled to create the lower roadway.
The new section of SR 99 is expected to open to traffic in early 2019. Track the progress of the ongoing project at this WSDOT website.