Finally we figured out what was blocking Bertha.
Highway 99 contractors revealed Friday what’s been blocking Bertha, the giant tunnel machine: The obstruction is steel pipe, left buried by a state groundwater study in 2002.
By Mike Lindblom
Seattle Times transportation reporter
A fragment of steel pipe pokes between spokes of Bertha’s cutting face, in this photo from Thursday’s inspection. It’s part of a 119-foot deep well, left in the soil after a 2002 groundwater test.
Chris Dixon, Seattle Tunnel Partners project manager, left, and Matt Preedy, deputy Highway 99 administrator for the state Department of Transportation, explain what is blocking Bertha.
State officials revealed Friday that the mystery object blocking tunnel machine Bertha is a long steel pipe, left buried in 2002 by one of the Highway 99 project’s own research crews.
The tunnel drill has been stranded for a month near Pioneer Square, with no clear strategy yet to extract the pipe.
The Department of Transportation (DOT) could not estimate how much time and money it will take to get the world’s largest drill moving again.
Bertha’s cutting teeth struck the pipe Dec. 3, yet the DOT and its contractors avoided mentioning the steel as a possible culprit for four weeks, despite an incident in which the machine knocked a 55-foot pipe fragment to the surface.
What the ongoing delay means for taxpayers is unclear, but it’s certainly not good.
The costs will be determined later through negotiations between the state and Seattle Tunnel Partners (STP), maybe even a legal dispute.
The $2 billion tunnel budget includes a $40 million risk allowance for repairs and inspections near the front of the rotary cutting face — plus a $105 million general contingency fund to deal with crises. Matt Preedy, deputy Highway 99 administrator for the state Department of Transportation, said some of that money will be consumed.
The culprit is an 8-inch diameter, 119-foot-long well casing, used to measure groundwater for the Alaskan Way Viaduct replacement project, officials said. Back then, a shallow cut-and-cover tunnel was a leading option.