World’s largest tunnelling machine “Bertha” debuts

13 August 2013

A five-story-tall machine known as Bertha is digging a tunnel to replace the SR 99 Alaskan Way Viaduct, a double-deck highway that has spanned the downtown Seattle waterfront for more than 60 years. This short video provides an overview of Bertha’s journey and the work the Washington State Department of Transportation is doing to replace the viaduct.


Video courtesy of WSDOT Communications.




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