Glued and Screwed

As I'm sure most of you have seen in the news since this Tuesday, the idiocy surrounding Boston's "Big Dig" central artery highway project
continues, and now has claimed an innocent life and shut down the very tunnel which was built to ease the access to Boston's Logan airport.
The project is probably the biggest single public works overrun in history, initially slated to cost $2.5 billion and ending up at over $14 billion, and G-d know's how much more will be needed to correct all the new construction screwups which pop up almost weekly.
Would YOU risk holding up heavy concrete ceiling panels by drilling UP into the concrete of the tunnel roof and EPOXYING six inch long threaded steel hanger rods into the holes? That's what the media is reporting as all that's holding up those huge concrete "ceiling tiles". I know I wouldn't, and though I'm not a structural engineer I can envision just too many installation variables which could screw up that kind of fastening system and go unoticed until something ripped loose.
http://cbs4boston.com/slideshows/local_slideshow_192143436
SWMBO and I flew back to Boston from a weekend wedding trip to Toronto yesterday morning, two whole days later than planned because of ongoing crummy weather and good old Air Canada's crew shortages. In over 50 years of airline travel all over the world, that delay beat my previous personal record. I was told by a fellow strandee that Air Canada's motto is, "We're not satisfied until you're not satisfied." <G>
Our cab ride home was tortuous because of the shut down tunnel, but I suppose we should be thankful, because if our original travel plans had come off as planned, we could have been going through that very tunnel Monday night at pretty close to the time "the roof fell in", albeit in the opposite direction.
The lawyers must be licking their chops right now, and the taxpayers can look forward to continued fiscal reaming.
Jeff
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Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
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The diagrams I see in my local paper suggest that the holes were drilled horizontally through
That's what the media is reporting as

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* wrote:
<snipped>

Could well be, I got my info from a radio interview I listened to yesterday of a man who sounded quite technically knowledgable. He described the holes as "drilled up" and went on to talk about how it would have been far better to drill right through the top of the tunnel and have used load distributing "large washers" and nuts "on top". He andwered questions by discussing differences in tensile and compressive strength of concrete, and the requirements for proper and careful proportioning and mixing of epoxy along with reasonable cure temperatures, so I had reason to believe he wasn't just another talking head.
If I got the orientation of the holes wrong, so be it, but it still shouldn't have happened and taken some poor guys wife from him, dammit.
Jeff
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Jeffry Wisnia
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Jeff Wisnia wrote:

A visit to the Hilti web site should get you some good info on the epoxy type anchors and pull out strengths. There is nothing at all wrong with the epoxy anchoring system, the epoxy penetrates into the pores of the concrete and makes full contact with the threaded anchor. Like typical glued wood, the glued connection is stronger than the surrounding material.
Now if the anchors were undersized for the load, the bearing tunnel concrete was inadequate, the embedment depth was inadequate, the epoxy was improperly mixed or water penetrated the concrete in the area and froze it could certainly fail.
Pete C.
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They've already indicted six people for fraud regarding concrete that was supplied to the job. No matter how good the anchoring system is, it will fail if the base material is weak. "Overseeing federal fraud and corruption investigation of the Big Dig, which was mainly funded with federal money. Recently indicted managers from concrete company Aggregate Industries NE Inc. in the alleged shipment of 5,000 truckloads of tainted concrete to the project." http://www.boston.com/news/traffic/bigdig/articles/2006/07/13/key_big_dig_figures/ Doesn't anybody wonder how they got an extra $12 billion in federal money for this project? This will turn out to be the second biggest scam of taxpayer money in the history of the US... once the levies are rebuilt around New Orleans. >;-} David

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No...the biggest scam is the 87 Billion that lined pockets in the Iraq deal.
--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
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wrote:

Surely they did slump tests before pouring and compression tests of all samples on curing. No major civil project in the world would skip those steps would it?
Mark Rand RTFM
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Mark Rand wrote:

>http://www.boston.com/news/traffic/bigdig/articles/2006/07/13/key_big_dig_figures /
Apparently..
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Posted via a free Usenet account from http://www.teranews.com


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Keywords:

Boston construction has a long history of fudging such things. In the early 1970's, there was a 16 story appartment building that partially collapsed when the construction company drop an air compressor on the roof. The floors were cantelevered off the central elevator shaft, and the top floor broke loose and dropped, hinging on the rebar at the core. It hit the next floor below, which also broke, and so on all the way down. During the investigation, they found that the concrete samples had never been tested. They had been hauled off and used to build a retaining wall for some big shot associated with the project.
I remember it because they took the remains down with a controlled implosion. I got up at 5:00 am to go watch. It was quite the show. The first set of charges cut the floors loose from the central core, and while they were stacking up in the basement, they set off a charge that started the core falling over. They then set off another charge that cut the core in half, toppling the top back in the other direction so the core folded up and dropped neatly on top of the remains of the floors.
Doug White
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snipped-for-privacy@alum.mit.edu (Doug White) wrote:

This is Boston; surely they bribed the testers. ;)
--
Free men own guns, slaves don't
www.geocities.com/CapitolHill/5357/
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Doug White wrote:
<snipped>

Wuzzat the one near the Brighton Newton line right near Boston College?
If it was, you and I were both there watching them implode it.
We had a home in Newton back then, maybe five blocks from that apartment fiasco. It was on a street off Commonwealth Avenue called Waban Hill Road North.
Thanks for the mammaries,
Jeff
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Jeffry Wisnia
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On Thu, 13 Jul 2006 13:02:28 -0500, "David Courtney"

Yall forget we in California do it bigger and better...
http://www.laweekly.com/general/features/the-subway-mayor/349/ http://antonovich.co.la.ca.us/pressrel/5/subway.htm http://www.signonsandiego.com/news/state/20030201-9999_1n1subway.html
A subway system, developed and built through the 80s as a major goal of mayor Tom Bradley, stretches from North Hollywood to Union Station and connects to light rail lines that extend to the neighboring cities of Long Beach, California, Norwalk, and Pasadena, among others. Also, a commuter rail system, Metrolink, has been added that stretches from nearby Ventura and Simi Valley to San Bernardino, Orange County, and Riverside. The funding of the Los Angeles County Metropolitan Transportation Authority project is funded by a half cent tax increase added in the mid 1980's, which yields $400 million every month. Although the regional transit system is growing, subway expansion was halted in the 1990s over methane gas concerns, political conflict, and construction and financing problems during Red Line Subway project, which culminated in a massive sinkhole on Hollywood Boulevard. As a result, the original subway plans have been delayed for decades as light rail systems, dedicated busways, and limited-stop "Rapid" bus routes have become the preferred means of mass transit in LA's expanding series of gridlocked, congested corridors.

"If I'm going to reach out to the the Democrats then I need a third hand.There's no way I'm letting go of my wallet or my gun while they're around."
"Democrat. In the dictionary it's right after demobilize and right before demode` (out of fashion). -Buddy Jordan 2001
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Notice, BTW, that those things are "in series". They ALL have to work right. You get screwed if ONE of them goes wrong.
There's another piece in the mix, too: the turnbuckles which connect the roof-anchored brackets to the "drop ceiling" runners. Clearly, they are meant to be adjusted so as to share the load as they fan out from the roof brackets. Clearly the adjustment is unlikely to have been perfect.
-- TP
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I agree with Pete. We installed a overhead track to remove and maintain safety and mainstop valves over a boiler using Hilti chemsets. Local authorities gave us a load limit of one tonne without any argument.
Tom
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Jeff Wisnia wrote:

Why didn't you ride the T in from the airport?
Yes, you got the hole orientation correct, the epoxied holes were vertical. Nobody's questioning the epoxy, it didn't give way, it was the concrete subcontractors ripping off the state that resulted in the failure. I believe they've already sent one batch of crooks to prison, probably should be many more.
GWE
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Grant Erwin wrote:

The concrete failed? That sounds like something that would happen in India after an earthquake. It seems like there should have been plenty of redundancy holding up something as heavy as those slabs. Maybe plates and washers and longer and more bolts than you think you need. Did the fan vibration loosen up something? They probably don't know yet.
--
"That's one of the tragedies of this life, that the men who are most in
need of a beating up are always enormous." -+Preston Sturges, "The Palm
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[snip]
I live in the Boston suburbs, and have been following the story.
This morning's Boston Globe said that the concrete was OK, but that the epoxy was grossly degraded, and went on to speculate causes for the bad epoxy: bad mix, contamination with water (either leakage from the river above, or because people cleaned the fresh-drilled hole out with water not compressed air) or oil (from failing to properly clean the threaded rod before installation).
I'm betting that when the anchors are pullout tested, most will fail and will be drilled out and reinstalled.
Mitt Romney (the governor) has been trying to replace the head of the Massachussetts Turnpike Authority for years; this time, Mitt will likely succeed. But it has little to do with safety. Getting control of the Turnpike Authority's money is a far more likely motive.
Joe Gwinn
Ref: <http://www.boston.com/news/specials/big_dig_ceiling_collapse/
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Joseph Gwinn wrote:

Because it's probably the same guy who did wrong whatever was done wrong over and over again. So how could they have non-destructively tested every bolt and still the problem wasn't detected?

Can you really believe that people will accept these things being reinstalled, I mean if they are mostly just cosmetic? Arguing for the "drop" ceiling is likely to get any elected official canned next election, in the least.
--
"That's one of the tragedies of this life, that the men who are most in
need of a beating up are always enormous." -+Preston Sturges, "The Palm
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"Bill Bonde ('The path is clear, though no eyes can see')"

[snip]
Today's paper said that they are in the process of pull-testing everything. And that some plates had already pulled 3/8" away from the concrete.
Because the bad epoxy may have been better a year ago, but is now degrading rapidly. Why the epoxy is failing has not yet been published.

Yes, they will. Nor do "people" have any reason to believe that some other method (which they never heard of before) is any better. One would expect the choice of methods to be left up to civil engineers with experience in such things.
Epoxying bolts into concrete is a standard and well-proven approach. If implemented properly. All methods can be devastated by improper application.
Though I bet they will use *far* larger bolts this time. And not cut so many corners. The fundamental problem was that the Big Dig was estimated and sold at $2.5 billion, but cost more like $15 billion, a 7:1 overrun. We are now discovering one by one the many corners that were cut under intense financial and political pressure.
The Governor of Massachussets has taken direct control of the effort, bypassing the Mass Turnpike Authority, and its doomed head.
Joe Gwinn
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Joseph Gwinn wrote:

I heard a report yesterday (Which I sure hope was spurious.) that in some instances, if the installer's masonry drill hit a piece of rebar short of full depth, they'd go ahead and use that "short hole" by just cutting the requisite amount off the end of the bolt they were about to epoxy into it.
Arrgh!
Jeff
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Jeffry Wisnia
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