The state Department of Transportation says it’s been concerned about the operations of tunnel machine Bertha since its July 30 launch — long before the blockage that has left it stranded 60 feet deep near Pioneer Square for more than a month.
In a note to lawmakers today, WSDOT Secretary Lynn Peterson said she has “concerns about the machine’s operations and critical systems.”
She’s requesting that contracting team Seattle Tunnel Partners (STP) forward to her several pieces of information by the end of work today. These include a plan to regain lost time. The drilling from Sodo to South Lake Union has been delayed by extra testing last winter in Japan, by a labor dispute in August — and now, since Dec. 6, by a blockage that officials say they don’t yet know how to resolve.
Peterson requested other details, such as why the giant drill operated at unusually high temperatures just before the Dec. 6 shutdown.
A couple of days earlier, Bertha had moved 58 feet in a single day, its fastest rate so far, shortly after hitting a buried pipe, DOT told the City Council on Monday.
Peterson also plans to convene tunneling experts to make suggestions — but she also warns that DOT can’t “direct how STP does their work” or else the state will bear increased risks and responsibility.
WSDOT has had concerns about the machine’s operations and critical systems since its launch on July 30, 2013. We have discussed these concerns with STP frequently over the past five months and this week sent a formal letter stating our concerns and asking STP how they will address them prior to tunneling under the viaduct and downtown. We are providing you [elected officials] with this information in lieu of a copy of the letter because it could be the subject of a potential future litigation between WSDOT and the contractor.
Meanwhile, STP planned to send a crew of five workers to the cutting face tonight to inspect for obstructions and damage, after four vertical shafts drilled last week failed to reveal exactly what has Bertha stalled. This work will be done in compressed but breathable air, at greater than atmospheric pressure. Workers will use flashlights and cleaning tools to get a look around the 57-foot diameter rotary cutter, and check around the cutter’s drive shaft.
Earlier today, Chris Dixon, STP project director, told The Seattle Times he didn’t suspect that the current stoppage was caused by mechanical flaws or internal damage, but by objects or problems in the ground. The conveyor screw, for instance, is moving muck and air just fine, he said. The $80 million drill, made by Hitachi, is still in a break-in period before final acceptance by the tunnel team, until it finishes 1,250 feet or so of mining.
And Todd Trepanier, DOT’s program manager, had told reporters earlier: “We’re confident in STP’s ability to move this project forward.” In recent weeks, the state has been referring to the steel pipe as only a partial reason for the stoppage.