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.

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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."

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

Reply to
Jeff Wisnia
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Jeff Wisnia wrote in article ...

The diagrams I see in my local paper suggest that the holes were drilled horizontally through

That's what the media is reporting as

Reply to
*

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

Reply to
Jeff Wisnia

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.

Reply to
Pete C.

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

Reply to
Grant Erwin

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.

Reply to
Bill Bonde ('The path is clear

================================== Murphy's Law strikes again....

Most likely the "big dig" problems are not the result of out-right fraud, but the conjunction of several "cost saving" [corner cutting] changes, any one of which would have not caused a catastrophic failure (but which may have reduced the safety factors), but which, when combined, were sure to. A classic case of the left hand not knowing what the right hand is doing until the ceiling falls in [literally].

Given the history of Boston politics, it was inevatable that "corner cutting" would be attempted, and indeed, it is highly likely the low bids were based on the assumption that (with a little help from the inspectors) "corners" could be cut.

A previous example was the collapse of the "Sky Walk" on July 17,

1981 in Kansas City that killed 114 people and injured more than 200. IIRC -- the group that was hosting the "tea dance" was the Kansas City Chapter of the American Trial Lawyers Association [perfect set-up for a good news/bad news joke]

see:

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When you go with the good-old-boy low bidders, use "fast track methodology," have divided command and control, and your inspection/verification procedures are compromised, the results are inevitable.

I see they are trying to "scapegoat" the chairman of the MTA [Mass. Turnpike Authority] and that Mitt Romney is "shocked, shocked*" to learn of the oversight problems

  • Casablanca see
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    How can you close me up? On what grounds? Captain Renault: I'm shocked, shocked to find that gambling is going on in here! [a croupier hands Renault a pile of money] Croupier: Your winnings, sir. Captain Renault: [sotto voce] Oh, thank you very much. [aloud] Captain Renault: Everybody out at once! Unka George (George McDuffee)

There is something to be said for government by a great aristocracy which has furnished leaders to the nation in peace and war for generations; even a democrat like myself must admit this. But there is absolutely nothing to be said for government by a plutocracy, for government by men very powerful in certain lines and gifted with the "money touch," but with ideals which in their essence are merely those of so many glorified pawnbrokers.

Theodore Roosevelt (1858-1919), U.S. Republican (later Progressive) politician, president. Letter, 15 Nov. 1913.

Reply to
F. George McDuffee

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 ta>>
Reply to
David Courtney

"Pete C." wrote

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

Reply to
tonyp

Properly engineered, sure. That's how I anchored the diving board on my swimming pool, and it worked great.

But then I didn't use mob concrete.

Reply to
Richard J Kinch

Right, decaying Hoffa bits don't qualify as aggregate...

Pete C.

Reply to
Pete C.

"David Courtney" wrote in news: snipped-for-privacy@individual.net:

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

Reply to
Anthony

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

Reply to
Mark Rand

Apparently..

Reply to
Jim

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

Reply to
Doug White

Jeff, I'm confused. Didn't I see that route 3 has been turned into parkland? WHERE do they re-route the traffic?

Steve

Jeff Wisnia wrote:

Reply to
Steve Smith

[snipped]

What I don't understand is WTF the heavy concrete ceiling panels are for. What possible reason is there for, as Jeff said, concrete "ceiling tiles"? They sound like they're cosmetic, not structural, and if that's the case, why not something light/simple/etc.?

OTOH, I'm not a concrete contractor, so maybe I'm biased.

Tove

Reply to
Tove Momerathsson

This is Boston; surely they bribed the testers. ;)

Reply to
Nick Hull

"Tove Momerathsson" wrote

The space between the "drop ceiling" and the tunnel roof is the ventilation duct. Allegedly, there can be hurricane-force wind in there. The tiles, we are told, needed to be heavy for that reason.

I know, I know -- it seems nutty to me, too.

-- TP

Reply to
tonyp

Seattle has a $100,000,000/mile tunnel under construction.

The problem with such structures is that they cannot deliver passenger miles cheaper than paying workers their salaries to stay home.

Those of us caught in traffic jams during commute can be thankful that at least we don't have one of Stalin's agents shooting out our brains with a Tokarev. We just have to suffer third world traffic while paying giant taxes that should provide a quick commute.

Out public works is better than genocide.

Reply to
Clark Magnuson

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