Posted April 4, 2017

Cool Stories: Big Bertha breaks through

Massive earth boring project nears completion in Seattle.

The giant tunnel machine, dubbed Big Bertha, broke thought to complete its nearly two mile long journey beneath Seattle today, April 4, 2017. Bertha began boring beneath the heart of the city in 2013. 

Maybe it's not on par with the pyramid of Giza, or even the Great Wall of China, but the tunnel that Bertha just bored beneath Seattle is still a marvel.

“Washington state and Seattle should have a lot of pride today,” said Joe Hedges, with the state Department of Transportation.

Crews stopped the drill Monday night, once it reached the other side of a five-foot thick concrete wall. It should push into the open air on Tuesday, completing a nearly two-mile long tunnel under the heart of the city.

“We're off slightly but it's only in the range of a couple of millimeters so we should break in right on target,” said Chris Dixon, the project manager with Seattle Tunnel Partners.

The problems along the way have been well documented. Bertha first punched into the ground in July 2013. By December, its components had shut down after striking a pipe. It took two years to repair - and a sinkhole briefly halted drilling again in early 2016 - but work has gone more smoothly ever since.

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