State: Tunnel contractor should have removed pipe that blocks Bertha

by: Graham Johnson Updated:

This image from WSDOT shows flattened pipe and boulders that came out of the tunneling machine prior to the stoppage.

SEATTLE, Wash. - Washington state transportation secretary suggests taxpayers might not be on the hook for the cost of the tunnel machine known as Bertha striking a steel pipe.

Lynn Peterson told KIRO 7 on Tuesday,  "There's contract language that requires things like this be removed by (Seattle Tunnel Partners)," the contractor building the tunnel.

The location of the steel pipe was provided in materials given to the contractor. It was installed in 2002 as part of a system for monitoring groundwater near the Alaskan Way Viaduct.

Peterson says there is a $200 million contingency fund built into the project, $40 million of which is set aside for running into things.

She said the cost of this incident is not yet clear and it is possible that more than the steel pipe  contributed to Bertha's blockage.

On Tuesday the state released photos of other items that went through the conveyor system before Bertha ground to a halt last month.  They include a small boulder, as well as pieces of steel from the well.

Peterson said it was not immediately clear that the pipe caused Bertha to slow and eventually stop after the machine chewed through it Dec. 3.

She says it continued tunneling an additional 90 feet before stopping, adding to the questions of what truly caused the slowdown.

On Tuesday crews began drilling shafts in front of Bertha that are 5 feet in diameter.

The drilling will help crews find and remove as much metal as possible still in front of the machine.

The steel pipe was 119 feet long and about 57 feet of it popped up out of the ground, leaving the rest still in the soil.

While Bertha can cut through many rocks and soils, it cannot easily cut through metal.

There's no timeline for when Bertha might be able to resume digging the new SR99 tunnel beneath downtown Seattle to replace the Alaskan Way Viaduct.

Editor's note: The story has been corrected. An earlier version incorrectly identified materials in the photo.

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