Bertha could breach two months early

Bertha could reach the surface later this week as the Seattle boring machine reaches its goal.

The machine boring a tunnel under Seattle is about 219 feet from its receiving pit near 6th Avenue and Thomas Street. That distance is less than the wingspan of a Boeing 747-8 jet, and sequoia trees are generally taller than that.

Related: You’ve never seen Bertha like this

The Washington State Department of Transportation has been silent as to any expected arrival date. Officials have only said that the “exact breakthrough date is TBD.”

KIRO 7 reports that WSDOT revealed Bertha is expected to reach its destination by the end of the week — March 31. That’s two months ahead of the department’s June expectation earlier this year.

Tunnel crews have been averaging about 50 feet per day since March 21. The machine traveled 45 feet from March 21-22. Then Bertha moved 55 feet. The next day it moved 50 feet, and 51 feet the day after that.

At this rate, the machine could reach its end point in just over four days.

Construction on the two-level roadway inside the tunnel is already underway. The Alaskan Way Viaduct replacement tunnel is expected to open in early 2019 — three years behind schedule.

KIRO 7 reports that Bertha’s recent movement has been largely due to the fact that the machine has required fewer and shorter maintenance periods in recent months.

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