The $US80 Million Machine Digging Seattle's Underground Highway Hasn't Moved In Months

Seattle tunnel viaduct projectWashington State DOTA surveyor inside the portion of the Seattle tunnel already dug out by Bertha.

An ambitious project to build a highway under downtown Seattle has been stalled since early December, and it will be quite a while before work resumes.

The idea of the $3.1 billion project is to demolish the Alaskan Way Viaduct, a waterfront highway that was damaged in a 2001 earthquake.

Drivers will go the two miles underground instead.

But the $US80 million tunneling machine charged with making that happen has broken down 60 feet below the surface, and repairs are going to take months.

Now some are wondering if it’s time to give up on the centrepiece of the $US3.1 billion Alaskan Way Viaduct replacement program.

Known as Bertha, the world’s largest tunneling machine weighs 7,000 tons and measures 57.5 feet in diameter. It began work in July 2013 and broke down in early December, after digging just 1,023 feet out of the planned 9,270.

The problem, according to the state’s Department of Transportation, is a damaged seal, which protects the bearing that allows the cutterhead to spin.

With Bertha 60 feet down, making repairs is complicated.

According to Crosscut, a Seattle-based news outlet, the only way to fix the seal is to dig a shaft to reach the front of the machine, or access it through the back of the rig. Either way, the work will take months, and workers still don’t know what caused the problem in the first place, the WSDOT says.

In a post on Seattle Transit Blog, Ben Schiendelman argued there are better ways to use the $US800 million the state has left in its project budget, like fixing the street grid to make the highway less crucial, and improving public transit:

It’s important, though, to consider the massive opportunity cost of spending this much money on such a high risk single project. The tunnel was justified over and over by proponents by asserting that surface/transit/I-5 couldn’t cover the required trips. Even at this late date, there is still enough money to address those problems, and dramatically improve the city’s environmental footprint and many other measures we care about.

Crosscut reports that when asked if it’s time to pull the plug on Bertha, Washington Governor Jay Inslee said, “I don’t think we’re at that point.”

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