Posted on 07/11/2007 9:00:02 PM PDT by Ernest_at_the_Beach
WASHINGTON, July 10 — The ceiling collapsed in one of Boston’s Big Dig tunnels a year ago, killing one woman, because builders used the wrong epoxy to hold the anchor bolts in place, the National Transportation Safety Board said Tuesday.
“We’re talking about the wrong glue here, in effect,” said Kitty Higgins, one of the five members of the board, which said that the epoxy selected dried quickly but lost strength weeks later.
A continuing theme of the board’s meeting Tuesday was how small a detail led to the accident. “It’s kind of ironic in a $14 billion project,” said Deborah A. P. Hersman, a board member. “About $1.50 per anchor is what ended up bringing the ceiling down.”
During construction, the builders tested the strength of the bolts; when some failed, the problem was attributed to installation errors, not breakdown of the epoxy.
“The knowledge of the engineering community seems to be deficient,” said Bruce A. Magladry, director of the board’s office of highway safety.
With concrete, steel and asphalt, he said, “once you test them for strength, they essentially keep that strength forever.”
“Epoxy is not that way, it’s a different material,” Mr. Magladry said.
Builders of a variety of other tunnels, some in New York, use epoxy, investigators said, but the panels being supported are much lighter.
(Excerpt) Read more at nytimes.com ...
The Fast Setting Epoxy loses strength after a few weeks...WHO KNEW....where are the engineers...?
Where’s the MONEY??
I should have tied it to the inevitable Boston political crookery and the entirely predictable inompetence of the politicos' sons'-in-law.
Silly me.
Norm,....isn't Bechtel HDQ in San Francisco?
Or cheaper epoxy means more Scotch for ol Ted
There was a communication error between the english instructions and the spanish/chinese/indian/polish/italian/arab builders.
Another Kennedy project results in a woman’s death. Heard this one before.
Politicians sniffing it is more like it.
Non-qualified installers using the wrong epoxy, and from what remember, the union types didn't know epoxy from Elmers White Glue, let alone how to properly mix and apply it, but they claimed the contract.
Romney's hands aren't exactly clean, but the MA Democrats did everything they could, and more, to hamper Romney in his bid to get a handle on the problems and waste - too many no-show patronage jobs and contracts, including legal firms in which MA legislators were partners, were at stake.
Heck, the solons would charge their own relatives for jobs.
“The supplier in Boston, Powers Fasteners, noted that the fast-set epoxy was not for long-term use but that information was “in the fine print,” said Mr. Magladry, and no one recognized that the material would weaken.”
Wow. I’m not an engineer, but even I know that fast set epoxy isn’t for the heavy duty, long term kind of jobs.
Did they say who was sniffing it?
Look for, the Union Label...
“The ceiling collapsed in one of Boston’s Big Dig tunnels a year ago, killing one woman, because builders used the wrong epoxy to hold the anchor bolts in place, the National Transportation Safety Board said Tuesday.”
Oh dear God, what an unbelievably careless mistake!
Too late... The job is done, the fall guys have fallen and the MA pols are quietly retired to Boca Rotten, the Elephant Burying Ground for dim-witted pols from all over the North East.
The issue really is bad joint design in an area where even a single failure is unacceptable. They should have used J- hooks, or some other type of positive mechanical connection to the steel structure. Suspending the weight of a tractor trailer using threaded rods epoxied into blind holes? Sombody watched too many Krazy Glue commercials.
There are so many factors that go into designing, producing, and qualifying high reliability adhesive bonds, that it just seems foolish to have allowed their use here.
Caulking should not be used in lieu of weather closure, an epoxy set anchor should not be placed in tension, and existing sub-soils should be proof rolled.
This was a design error before any error first and foremost.
If for some highly unlikely reason it was necessary, then special care in the specification of the material including a sample test and frequent field tests should have been specified.
Often times the trade contractor in the field has three days to order out the material needed for a procedure where the designer has three years to select and specify it.
Don't get me wrong, I've seen small plumbing contractors paint a fitting a bright copper color to try and make a stupid substitution out os stupid attempts to not have to stop work and pay for the right part, but this smacks of the threaded rod design on the Hyatt Regency Skywalks collapse.
Construction is not my field, but I have built a lot of stuff to last, and I do know epoxies. Your points about sample collection and field test are spot on.
To me this situation looks like an afterthought. Either it’s a bandaid on another design issue, or somebody decided to dole out some extra steel and concrete contracts.
BTW, one of the biggest factors I’ve seen in epoxy joint durability is thermal cycling. Under a car’s hood these can be extreme and frequent, but in a tunnel are they considered a factor? Is accelerated life testing used in design qualification?
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