No Easy Answers for Boston's Troubled Big Dig
JOHN YDSTIE, Host:
The tunnels in Boston's Big Dig highway system remain closed, more than a week after a woman was killed by a falling concrete ceiling panel. The closures have caused major traffic problems and affected businesses and tourism. State transportation officials are testing new systems for holding up the ceiling panels, but the number of problem areas continues to grow.
From member station WBUR in Boston, Shannon Mullen reports.
SHANNON MULLEN: Governor Mitt Romney, says the number of trouble spots inspectors have discovered in Big Dig tunnels has more than doubled in the past two days.
MITT ROMNEY: The reason for that increase, is that now we consider all of the bolts - not just those that were hanging down a 16th of an inch - but all of the bolts, all of the connectors, we believe are of concern.
MULLEN: In fact, he's calling the system of using epoxy and anchor bolts to hold up concrete ceiling panels, A systemic failure. He says more than 1400 panels will need to be reinforced, and officials have begun field tests on possible techniques. At a news conference yesterday, Romney Drew diagrams of three methods. He highlighted one that uses what are called undercut anchor bolts to hang ceiling panels. Romney says this type of bolt carves away at the concrete, when it's drilled into the tunnel body, creating an internal overhang for itself so it can't be pulled out.
ROMNEY: It literally cuts a special channel inside that concrete, which is approximately double the diameter of this hole that's been drilled. So you create an expanded area. That's why it's called an anchor bolt. It opens up on the inside of the concrete and anchors.
MULLEN: Independent engineer Richard Wollmertsauzer(ph) says it's similar to the type of expanding screw that can be used to hang a heavy picture frame on a wall.
RICHARD WOLLMERTSAUZER: It's a heavy-duty version of that. They're designed so that once they're installed they stay in, and they don't come out until the steel breaks.
MULLEN: Wollmertsauzer is the technical consultant to the company that makes the bolts Massachusetts's officials are testing. He's hesitant to endorse their use in Big Dig tunnels without seeing the design specifications.
WOLLMERTSAUZER: It would depend on the specific design parameters. Are they going to replace those concrete slabs with something else? Same weight, lighter weight, who knows?
MULLEN: But he says it's a good application of the technology, and there's none of the worry about mistakes in mixing, handling, or applying epoxy, that could weaken its ability to secure anchor bolts.
The state's attorney general is investigating whether epoxy errors were a factor in the panel collapse, as part of an ongoing criminal investigation into the incident. Governor Romney says his focus is on fixing the tunnels, not pointing fingers. But there's one question he agrees needs answering.
ROMNEY: Clearly everyone wants to know. We've heard that there's a three- year cycle for inspection of the tunnel. What we want to know is was the three- year cycle adhered to? Was this tunnel inspected after it was opened in 2002? And if it was not, then that obviously is a real concern.
MULLEN: The Massachusetts Turnpike Authority would have overseen those inspections. When asked if they took place as required, agency officials say they're reviewing their records to find out.
For NPR News, I'm Shannon Mullen in Boston.
YDSTIE: This is NPR News.
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