From Today's Globe:
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US agency eyes blasting as reason for loose bolts
Will examine drills, weather
WASHINGTON -- Federal investigators are examining whether blasting at a nearby office construction project jostled loose epoxy-secured ceiling bolts in the Interstate 90 connector tunnel where concrete panels fell on Milena Del Valle, said lawmakers briefed on the probe yesterday.
National Transportation Safety Board investigators are also looking at whether Big Dig construction workers used a certain type of drill bit for the ceiling bolt holes that may have lessened the epoxy's adhesive power, the three lawmakers said.
In addition, federal investigators are exploring whether cold weather conditions during part of the I-90 tunnel's construction reduced the epoxy's bonding strength, said the lawmakers, who spoke on condition of anonymity because the investigation is ongoing.
One or more of the issues could prove to be significant in the safety board's investigation into what caused the ceiling collapse that killed Del Valle, which is focusing on problems with epoxy-secured bolts.
The NTSB investigators told the lawmakers at a closed-door Capitol Hill meeting that they have ruled out that the concrete in the I-90 connector ceiling failed when Del Valle was crushed to death on July 10.
The Massachusetts lawmakers also said that federal transportation officials are looking into whether Bechtel/Parsons Brinckerhoff, the Big Dig project manager, had so much control over the mammoth project that government oversight was compromised.
``They pointed to it as being a root cause of some of the difficulties. . . . There was no one checking the checkers," said US Representative Stephen F. Lynch, a South Boston Democrat, after emerging from a briefing with officials from the safety board and the US Department of Transportation, whose inspector general is examining the management of the entire $14.6 billion project.
The safety board, which investigates transportation accidents, is focused on determining the cause of Del Valle's death. Its inquiry is in the preliminary stages, and a final report is expected in nine to 12 months, said a spokesman for the board. Its investigation is running parallel to state Attorney General Thomas F. Reilly's criminal investigation, though both are examining much of the same evidence and data.
Among a range of potential causes for the suspected failure of the epoxy-secured bolts in the I-90 connector tunnel, the safety board is examining whether blast vibrations or the movement of heavy equipment to and from the construction site of the 14-story
The soaring glass-and-steel building on Congress Street sits at the lip of the I-90 connector section where Del Valle died. Construction started in 2001, about a year after the tunnel's epoxy-and-bolt ceiling fixtures were in place, and was completed in 2004, a year after the I-90 connector tunnel opened.
The federal investigators are also looking at whether diamond-tipped drill bits were used to make the holes for the epoxy-secured ceiling fixtures, lawmakers said. Carbide bits create a rougher surface within such holes, increasing the adhesive strength of the epoxy, while the smoother surface created by the diamond tip slightly lessens it, according to engineers.
In 1999, after five bolts failed strength tests, Big Dig engineers said ``that it was not possible to use a carbide bit," the preferred type, on the I-90 connector bolt holes, according to a Bechtel/Parsons Brinckerhoff memo obtained by the Globe. The portion of the memo obtained by the Globe does not make clear why the bit could not be used in the tunnel's concrete.
That same memo mentioned that the temperature when bolts were installed was an area ``of concern." The bolts that failed the 1999 strength tests were inserted in July and August, and the memo concludes ``temps in the tunnel were considerably above the minimum required."
Most of the bolts were installed before the winter, but records show some bolts being installed in December 1999 and January 2000. When epoxy freezes, then thaws, its bonding power can lessen.
US Representative Michael E. Capuano, a Somerville Democrat, and other Massachusetts lawmakers interviewed yesterday after emerging from a nearly two-hour closed-door meeting with investigators said they were satisfied that the two federal investigations underway would be comprehensive, despite the fact that one is being conducted by the inspector general of the Federal Highway Administration, whose chief administrator, J. Richard Capka, ran the Big Dig for 18 months beginning in 2001 as chief executive of the Turnpike Authority.
``I have a good deal of confidence" in the federal investigations, said US Senator Edward M. Kennedy, a Democrat.
While officials met in Washington, work on tunnel repairs continued in Boston. State engineers and private contractors grappled with problems discovered in recent days in the Ted Williams Tunnel and on several ramps, adding to the list of fixes already being planned for the I-90 connector.
Last night, state engineers closed one lane of an offramp from the westbound Ted Williams Tunnel to South Boston to examine two massive jet ceiling fans that they fear are unstable. That ramp is a detour for traffic leaving Logan International Airport.
Also, engineers closed the Essex Street onramp to I-93 for two hours last night to inspect the epoxy-secured bolts that anchor the ceiling panels there.
A second day of pull tests continued on a sample of the 12,000-plus bolts in the Ted Williams Tunnel. And on the I-90 connector where Del Valle died, engineers were still working yesterday on designs for a ceiling fixture system that uses anchor bolts that don't use epoxy and will back up the original one that uses epoxy-secured bolts. The plans require federal approval.
``We're working to get them done as soon as possible," said Jon Carlisle, a state Transportation Department spokesman. ``We're nearing completion as far as approval and finalizing these designs."
Sean P. Murphy and Rick Klein of the Globe staff contributed to this report. Raja Mishra can be reached at rmishra@globe.com, and Scott Allen can be reached at allen@globe.com. 
© Copyright 2006 Globe Newspaper Company.
