Paint failure on hundreds of tunnel light fixtures in Boston’s infamous Big Dig project is apparently causing the fixtures to corrode—and one 110-pound fixture, so far, to fall out, officials say.
Part of the ceiling of the Big Dig collapsed in
2006, killing a 38-year-old motorist.
An 8-foot-long fixture crashed into the travel lanes of the $20 billion tunnel on Feb. 8, luckily missing morning commuters. Highway crews cleaned up the casing, which a passing motorist had reported as debris on the road.
After the accident, Massachusetts’ Department of Transportation launched an inspection of the tunnel’s 23,000 light fixtures. However, the agency did not inform the public or the governor of the accident or the inspection.
350 Corroded Fixtures
MA DOT’s inspection, now 95% complete, has found nearly 350 light fixtures with some degree of corrosion, State Transportation Secretary Jeffrey B. Mullan told reporters at a briefing last week. Most of the damage occurred at the tunnel entrances, he said.
"We learned that this is a relatively isolated incident, but it's something that we're taking very seriously,' Mullan said.
He added, however: "There is no question in my mind that the tunnels are robust and safe for the traveling public. We've done an individual inspection of each of the lighting fixtures that is over the travelway, and we know that they are secured adequately and that the tunnel is safe."
Mullan blamed the problem on corroded aluminum support casings that hold the fluorescent lights by clips. The corrosion was caused in part by harsh weather and road salt, Mullan told reporters.
Mullan said that 3,000 clips, out of some 230,000, were shifted to non-corroded areas as part of a temporary fix and one fixture was removed, the Boston Herald reported. The cost and design of a permanent fix have not yet been determined.
Meanwhile, MassDOT has identified paint problems as the cause of the corrosion.
In a letter Wednesday to NuArt Lighting of Fullerton, CA, which supplied the lighting for the Big Dig, MassDOT reported “two serious problems with your tunnel lighting fixture wireway.”
The letter, signed by Helmut R. Ernst, P.E., District 6 Highway Director, said: “Paint is not adhering to the wireway and is flaking off. The loss of paint is allowing the bare aluminum to be exposed to environmental elements within the tunnels, causing excessive corrosion and premature failure of the wireways.”
In addition, Ernst said, the “extruded longitudinal lip that captures the stainless steel light fixture mounting clip is corroding under the stainless steel clips. In many instances, it is obvious this corrosion is due to paint failure under the clip, allowing a galvanic reaction to occur between the stainless steel clip and the aluminum wireway.
“Numerous failures appear to be associated with the stainless steel light fixture mounting clip cutting through the paint and coming in contact with the aluminum wireway.”
State officials say the lights cost tens of millions of dollars, although an exact figure was not immediately available.
Mullan said he had not told Gov. Deval Patrick or motorists about the corrosion problem or light collapse for five weeks because he wanted to gather more information first.
Mullan told the governor about the problem only last Tuesday (March 15), and Patrick told Mullan to notify the public, which he did the next day, the governor’s office said.
Wherever that finger-pointing leads, lawmakers want answers.
Rep. James Miceli of Tewksbury, of the legislature’s transportation committee, is calling for public hearings. Miceli said he wanted to know, among other things, how inspectors missed corrosion on the light fixtures.
Miceli told the Boston Herald that he drives through the tunnel “with trepidation, I really do And I’m not one of those guys who’s running scared.”
He added: “Knowing what I know, and I don’t want to cause a panic, I, when I can, avoid the tunnel.”
Fatal Ceiling Collapse
The lighting accident occurred five years after a three-ton concrete ceiling tile in the tunnel fell and fatally crushed a 38-year-old passenger in a car. That accident, which occurred five years after the tunnel opened, was traced to "use of an epoxy anchor adhesive with poor creep resistance" that could not sustain long-term loads.
The fatal accident was followed by a “stem-to-stem” visual inspection of the Big Dig tunnels. Mullan said that inspection showed no problem with the light fixtures.
The companies that oversaw the Big Dig, Bechtel and Parsons Brinckerhoff, ultimately paid the state $400 million to settle claims of shoddy workmanship, including a 2004 episode in which a breach in the wall sent water gushing into a tunnel, the Boston Globe reported.
It was later revealed that the tunnel was riddled with leaks in its roof, the Globe said. The Turnpike Authority, which managed the Big Dig until 2009, acknowledged in 2007 that hundreds of leaks remained and that plugged leaks were regularly reopening.