While it's certain that the machine digging the Highway 99 tunnel under downtown Seattle did grind to a halt last month shortly after hitting a steel pipe, plenty of mystery still surrounds the idled earthmover and the future of the multi-billion dollar megaproject.
Lingering questions about the cause and cost of the machine’s stoppage were on full display Monday, as state Secretary of Transportation Lynn Peterson and Washington State Department of Transportation staffers briefed the Seattle City Council.
The WSDOT representatives said it was still too early to know much about the price of the delays or whether the pipe was the only problem afflicting the machine, known as Bertha. Peterson also discussed WSDOT's decision to hold Seattle Tunnel Partners — the contractor group running the project — in breach of contract for failing to give an adequate amount of work to minority and women-owned companies.
WSDOT program administrator Todd Trepanier acknowledged that WSDOT and Seattle Tunnel Partners were under "a lot of presssure" to estimate the cost of the stop-down and when the machine would get moving again. “It would be irresponsible at this time," he said, "for us to really speculate on all those issues."
The machine has bored about 1,000 feet of the 1.7-mile long tunnel. WSDOT representatives said the contractor and the agency expected the first 1,500 feet of digging to be a “shakedown cruise.” But on Dec. 3, the tunneling machine hit an 8-inch diameter, 119-foot long, steel well-pipe left in the ground by a WSDOT contractor in 2002. In the days that followed, the machine began to experience increased resistance moving forward. The current boring stoppage began on Dec. 7.
The well site was noted in planning documents for the project, but a Seattle Tunnel Partners project manager said recently that the pipe should have been removed when the well was decommissioned.
Matt Preedy, WSDOT Alaskan Way Viaduct Replacement Program deputy administrator, said on Monday that probing the ground in front of the machine had not helped to confirm the root of the tunneling machine’s troubles.
“All of our ground investigation out in front of the machine has been inconclusive,” he said.
Trepanier said the pipe might not be the only problem. “I think maybe that is a contributing factor," he said. "But there are other issues that are being dealt with and wanting to be understood at this point in time on why this machine stopped.”
There have been difficulties, he said, with material not flowing correctly through the machine and wear to its metal teeth, which weigh about 1,200 pounds each.
“I don’t necessarily agree with the word stuck,” Trepanier said later, referring to Bertha’s current status. “The cutter head turns, you can mine with this machine. It would be like driving in your car and the warning light is coming on and telling you to stop.”
Regardless of whether the machine is stuck or stopped, the delays are raising concerns in Seattle. A provision in the state bill financing the project says that any costs beyond $2.8 billion will be paid for by “property owners in the Seattle area who benefit from replacement of the [Alaskan Way Viaduct] with the deep bore tunnel.”
Mayor Ed Murray, who co-sponsored the bill during his time as a state Senator, says he’d like to convince legislators in Olympia to remove that language from the law.
At the briefing on Monday, council member Sally Bagshaw pressed the WSDOT representatives on what the current delays mean for the city's finances.
“You’re talking about cost overruns potentially. One thing I want to clarify is that the city of Seattle is not on the hook to pay those cost overruns,” said Bagshaw. “The city is not party to the contract between you and the state and the partners, is that correct?”
“You’re stepping into an area that is a little beyond my understanding,” replied Trepanier.
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