BOSTON – Repair crews were testing methods for fixing the Big Dig's highway tunnels Tuesday after inspectors found more than 1,100 unreliable bolts and Gov. Mitt Romney declared that none of the tunnel's ceiling bolts that used epoxy could be considered safe.
Romney said tests show that more than 1,100 bolt assemblies that used epoxy and more than 300 other areas in the Interstate 90 connector tunnel complex are unreliable.
All will have to be reinforced, he said.
"In grabbing ahold of these bolts and pulling on them with excess force, they're letting go ... at lower pressures than they were designed to handle," Romney said. "That suggests that this epoxy system is not working."
The inspections started last week after 12 tons of concrete ceiling panels came loose inside an Interstate 90 connector tunnel and crushed a car, killing a passenger. Two Big Dig tunnels have since been closed for inspections and repairs, and the governor said he was concerned about the impact on traffic, business and tourism.
The $14.6 billion highway project, the most expensive in U.S. history, buried much of the city's highway network in tunnels. It took over a decade starting in the early 1990s to complete and has since been plagued by leaks, falling debris, cost overruns, delays and problems linked to faulty construction.
The suspect bolt assemblies that the governor described Monday used epoxy and are the same type as the ones that failed, causing the ceiling panels to collapse on the vehicle. Thousands of other bolt assemblies in other parts of the tunnel complex were constructed differently and are not believed to pose a risk.
Romney said engineers had successfully tested a system to reinforce the bolts.
With crews working around the clock, at least one portion of the closed areas could be reopened by late in the weekend, he said. But the entire area might not reopen for at least two months.
Attorney General Tom Reilly, who is considering criminal charges in the ceiling collapse, said Monday that investigators had discovered documents showing there was a "substantial dispute" from 1999 to 2000 over whether the design of the connector tunnel was adequate to hold the weight of the 3-ton ceiling panels.
Reilly, who refused to give specifics, said he did not know how the dispute was resolved. He said the tunnel designer, the contractor and the company overseeing the Big Dig project were involved but would not say who raised the questions.
The contractor on the tunnel, Modern Continental Construction Co., issued a statement saying it was cooperating with the investigation and is "confident that our work fully complied with the plans and specifications provided by the Central Artery Tunnel Project."
Messages left with project manager Bechtel/Parsons Brinckerhoff and tunnel designer Gannett Fleming were not immediately returned.
Commuters on Monday endured increased traffic hassles with the closing of a second tunnel ramp connecting two interstates. It was closed Sunday after testing showed dozens of problems with the bolts holding up the ceiling. That ramp had been used as part of a detour around the accident scene.
Romney met earlier in the day with congressional, state and city leaders to outline his plan for traffic and to ensure the safe reopening of the tunnels. After the meeting, Sens. John Kerry and Edward M. Kennedy endorsed the governor's plans.
Kennedy said congressional committees are making plans to hold hearings into the tunnel collapse and the Big Dig project.
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