Three loose bolts, one of which had dislodged about 1.3 centimeters, were found at the westbound entrance to the Ted Williams harbor tunnel on Monday. Traffic was diverted around the questionable panel, and it was shored up with a portable support device.
"This is a precautionary step. There was no sign of failure, but we are erring on the side of public safety," Jon Carlisle, a spokesman for the state Highway Department, said Monday night.
A connector tunnel system leading to the eastbound side of the Ted Williams Tunnel, as well as ramps leading from the Boston end of the westbound section, have been closed since several 3-ton concrete ceiling panels in the connector tunnel crushed a car on July 10, killing 39-year-old Costa Rican native Milena Del Valle.
The bolt-and-epoxy system holding up the ceiling panels in those tunnels has been the focus of the subsequent investigation.
The tunnels are part of the $14.6 billion Big Dig project, the most expensive in U.S. history. The project, which buried much of the city's highway network in tunnels, took over a decade to complete and has since been plagued by leaks, falling debris, cost overruns, delays and problems linked to faulty construction.
The Ted Williams Tunnel's panels are lighter and its suspension system considered more substantial than the one that collapsed. But the eastbound tunnel was closed for a day last week when two bolts were found to have slipped. Those areas are being reinforced with the same type of portable device as the westbound panel.
Gov. Mitt Romney has said the Ted Williams Tunnel, which extends Interstate 90 between downtown Boston and Logan International Airport, would get daily inspections until pull tests on the ceiling panels could be completed.
The latest problem was discovered hours after Massachusetts Turnpike Authority Chairman Matt Amorello, who has overseen the beleaguered Big Dig project, filed a lawsuit seeking to prevent the governor from holding a hearing on Thursday seeking to demote him from his $223,000-a-year post.
Romney has long criticized his management of the Big Dig project, and renewed calls for his ouster as chairman since the fatal ceiling collapse. Amorello's lawyers contend that the governor does not have the authority to demote him.