Originally posted at 2:50 p.m. and moved up with details.
Bertha, the world's largest tunnel boring machine, has an increasingly dire prognosis after officials discovered yesterday that she had struck an eight-inch-diameter, 119-foot-long steel pipe last month that brought the 57-foot wide behemoth to a halt and caused severe damage to the machine's cutterhead. But that's just the beginning of the troubles for the state megaproject: The steel pipe was placed there by a state-hired contractor for water-well tests in 2002 related to the highway project but was not removed as it should have been, officials from the state and tunneling company revealed at a press conference this afternoon, thereby ultimately placing fault with the state for leaving the object behind and sending a tunneling machine into its path.
And that pipe may be only the beginning: Crews have since sampled the soil ahead of the stalled machine and discovered more likely metal obstructions in tunnel digger's path, which all must be somehow removed before Betha can move again.
"We have probed 12 holes and encountered other obstructions in six of those holes," said Chris Dixon, the program manager for Seattle Tunneling Partners, which has a billion-dollar contract with the state to dig the tunnel (his company is not the same contractor the state worked with in 2002 that installed the pipe). Those obstructions are not believed to be boulders or timber, he said, leading him to believe they are "metal objects." (WSDOT's website claims that out of 17 soil samples, officials found four obstructions.) The tunneling machine, which is designed to churn though soils and break boulders, cannot chew through metal.
- This diagram provided by WSDOT.
"We need to remove the other pieces of metal so we do not cause further damage to the tunnel boring machine," said Matt Preedy, the state's deputy program administrator for the project. "We don't want to push the limit with this thing," he added, noting that the multi-million-dollar machine has completed about one-tenth of its route and must remain in working order. He said officials don't know "if the pipe is the only issue or one of several" and it would take "a little while to explore" the situation. He provided no timeline or specific strategy for removing the objects.
It's fair to say that this amounts to a colossal setback for the megaproject—one that many worried would become a boondoggle.
The deep-bore tunnel is the largest part of a $4.2 billion project to replace the Alaskan Way Viaduct, a project that has been subject of controversy due to speculation of delays, unprecedentedly complicated logistics, cost overruns, and financing problems. Already a labor dispute delayed the project for a month, in addition to this latest month-long pause. Meanwhile, a contingency fund originally proposed at some $415 million was cut down to a fractional $40 million, shrinking the margins for affordable errors. The budget also requires $400 million in funding from tolling, but latest projections show the state may only collect about $165 million. All of these delays, costs, and revenue shortfalls raise red flags—particularly when just one-tenth of the tunnel has been dug—because state law prohibits spending an additional funds if the project runs over budget.
The state and Seattle Tunnel Partners refused to answer many key questions today: Reporters pressed them about the cost per day of delay, the estimated length of the delay, why, exactly, the metal pipe was not removed, what the other metal objects may be in Bertha's path, the nature of changes to contracts since digging began, or how many days of stalled operations the project can handle before running into delays and cost overruns. Officials stonewalled or feigned ignorance on the answers.
Trouble began on December 3, when Bertha first hit the vertical pipe, which was part of a water well that plummets some 100 feet below the surface, but Bertha plowed through it anyway. Two days later, the machine was too belabored to proceed. "We did not know the pipe was there," explained Dixon. "Tunnel boring machines do not interact well with metal," he continued. "The cutterheads cannot cut steel. The fact that it performed well for two days [after first hitting the pipe] gave us a false sense of security."
Grinding through the metal with its six-story-high rotating head of gnashing blades, the cutterhead sustained "unusual damage" to many of those cutting tools, said Dixon. He added that it takes several hours to replace each tool and "the device has hundreds of tools."
Dixon pointed out the pipe, a metal well shaft, was an unexpected obstacle because such objects are "usually... decommissioned from the ground."
Speaking for the state, which was ultimately responsible for removing the pipe, Preedy said it was "placed there for a preliminary exploration" by a state-hired contractor in 2002 early on during the Alaskan Way Viaduct Replacement Project. "The location of the well [pipe] was described in certain documents," Preedy said. But as to contracts to remove that pipe and whether the state would incur contractual liability for failing to remove it, he said, "We don't want to talk about contracts."