Big Bertha TBM Ends Journey Underneath Downtown Seattle (Video)

Back on April 4, 2017, one of the world’s largest tunnel boring machines (TBM) named Big Bertha chewed through more than 1,000 tons of concrete and fiberglass to end a 1.7 mile journey underneath downtown Seattle.

Bertha was built specifically for the Washington State Department of Transportation’s (WSDOT) Alaskan Way Viaduct replacement tunnel project in Seattle by Hitachi Zosen Sakai Works in Osaka, Japan.

With a drone’s eye view, this video shows the raw power of Bertha’s breakthrough – start to finish. This is a marvelous feat of engineering if you ask us.