More problems for tunneling machine Bertha



SEATTLE - After tunneling just 2 more feet, the machine known as Bertha is in trouble again.

Friday morning, the state revealed the giant machine built to dig the tunnel to replace the Alaskan Way Viaduct overheated during a short test.

The state Department of  Transportation said warning lights that indicate above-normal temperatures went off Tuesday when the machine inched forward in a test run.

In early December, days after chewing through a steel pipe and some rocks or boulders, Bertha gave those same warnings.

Engineers decided to stop the machine.

In a news conference Friday, a DOT administrator said the overheating is associated with the rotation of the cutterhead.

“They are looking to understand what that might mean. Tunneling and these machines are very, very complex. This is not unique, this is not expressive of some sort of overall concern with the machine,” said Todd Trepanier with WSDOT.

Bertha sat idle for nearly eight weeks while crews pumped out water near the cutterhead so specially trained workers could do inspections.

Those inspections didn't find much.

The state has hired outside tunneling experts to review the problems with Bertha.

They plan to meet in the next week to figure out what happens next.

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