A new schedule has Bertha, the world's largest tunnel-boring machine working to dig the new Seattle tunnel, back to digging in late November. Bertha has been shut down since December 2013 after only excavating 1,083 feet into the 9,270-foot tunnel for the new Highway 99, which will replace the Alaskan Way Viaduct.
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The machine was shut down and eventually removed so repairs could be done to the cutterhead. Crews started installing a new main bearing in mid-July.
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Once operational, Bertha is expected to take one year to excavate the remain portion of the tunnel. The new schedule now has a completion date of spring 2018 compared to the original target date of November 2016.
