WTC7 and the girder walk-off between column 79 and 44

[ozeco41]

Also, could it have been different from the plans, and the as built specs?

I know that occasionally, something is substituted in a plan, and signed off by an engineer, but wouldn't show up in the shop drawings.

Could this be the case?

If this is the case, then of course C7 will need to apologize for calling the engineers liars.

ETA: DGM and others already beat me to this.

I would be very surprised if the "as built" building matched the original design drawings in all the minor irrelevant details for any building. WTC"X" being no exception.

And whether the support was 11" or 12" is an irrelevant detail. Either dimension is wide enough to form the seat for the beam. End of story.

The only reason we are discussing it is because some truthers want to avoid discussing the real issue - "CD or not?" and they have gone nit picking for a detail which they can discuss round in circles interminably thereby preventing any discussion of real issues.

We should not fall for these tactics.....but we seem to take the bait every time....

And we have the old "reverse burden of proof" in play yet again. The difference is not relevant - let the truthers establish their claim that it matters. And garbage claims about liars should be ignored with the contempt that they deserve.

 

[MarkLindeman]

The only reason we are discussing it is because some truthers want to avoid discussing the real issue - "CD or not?" and they have gone nit picking for a detail which they can discuss round in circles interminably thereby preventing any discussion of real issues.

To be honest, I'm not convinced that that is the case. I think C7 thinks that this particular detail really is crucial to NIST's account of the collapse -- not just in the sense that the probable collapse sequence would have to be revised, but in the sense that NIST could no longer account for the failure of Column 79 at all. Naturally, he perceives that as germane to the issue of "CD or not."

All that seems quite fallacious to me. But all in all, it's more interesting than most such discussions. I wouldn't be surprised if we have reached the death spiral stage now.

 

[ozeco41]

To be honest, I'm not convinced that that is the case....

It could be that some truthers have lost the plot as to what is driving their motivation. "They", like "us", have been discussing down these sideline issues for so long that many on both sides of the polarised debate have forgotten how and why they got where they are. That does not change the reality or the logic - there are only two reasons for discussing these matters - either because they are being put forward as support for CD OR they are of intrinsic interest as stand alone issues. And, stand alone, why are we discussing them in the setting of 9/11? (some bits of irony behind that comment - but I won't drift of my theme.)

...I think C7 thinks that this particular detail really is crucial to NIST's account of the collapse -- not just in the sense that the probable collapse sequence would have to be revised, but in the sense that NIST could no longer account for the failure of Column 79 at all. Naturally, he perceives that as germane to the issue of "CD or not."....

...or may choose to represent that as his position. It is a hard position for a person of some intelligence to honestly hold. Recent claims are laughable.

...All that seems quite fallacious to me. But all in all, it's more interesting than most such discussions....

If you mean a minor discrepancy between various revisions of the design drawings and/or what was actually built I don't share your view that it is interesting. Simply situation normal for any engineering project I have been involved with. Revising drawings to what we Aussies call "Work As Executed" and members here call "as built" is driven by several factors. But bottom line is you don't spend money chasing to correct irrelevant minor details. So that is the real world reality. If C7 has you or any others persuaded that this one minor point is of significance I will leave you with that opinion. It does not persuade me.

I wouldn't be surprised if we have reached the death spiral stage now.

Death spiral for this issue or death spiral for 9/11 conspiracy discussion?

I agree on the latter. As far as the technical issues of 9/11 are concerned the discussions are all over. From the main claims down - there was no CD at WTC, it was that plane which struck the Pentagon and the Shanksville crash was not a "shoot down". 10+ years on and no realistic alternative published anywhere to any of trhose big three. So all we are discussing is subordinate issues which on ly exist as potential support for the "big three' - in this case WTC demolition claims. And for several years we have been chasing truthers and trolls down side lines of those subordinate issues. ThermXte - a derail evasion sideline. Ditto iron microspheres -- a deviation of a deviation.

 

[Christopher7]

When the mistake involves a large percentage error, on a basic critical engineering dimension, published in a final report by a prestigious U.S. government engineering agency, it is reasonable to examine the investigative consequences of this "innocent mistake"?

MM

That is the PC way of saying it.

MarkLinderman is asking the same questions over and over so I won't bother responding to him directly again.

It is obvious to an objective person that NIST could not have innocently mistaken the notation on the drawings - under Feet/in./16th is 1/0/0 [see post #8]
How anyone feels about whether it was a lie or not does not change the result so that's just a diversion.

He is trying to shift the focus from the false statement in the final report that I have posted several times.
NCSTAR 1-9 Vol.2 pg 527 [pdf pg189]
"A girder was considered to have lost vertical support when its web was no longer supported by the bearing seat. The bearing seat at Column 79 was 11 in. wide. Thus, when the girder end at Column 79 had been pushed laterally at least 5.5 in., it was no longer supported by the bearing seat."

I have also posted the reason why this is significant but MarkLinderman keeps asking about that too. So here it is again.

From post #79 [with beam length from drawings]
Using the formula on page 343-344 0f NCSTAR 1-9 Vol.1
Using the length of the beam.

The floor beam closest to column 79 was 53' 8 11/16". When a 644.7 in. long beam is heated so as to uniformly increase its temperature by 600 ºC, and the coefficient of thermal expansion is taken to be 1.4x10^-5 / ºC, the elongation would be,
St= (1.4x10^-5 / ºC) × (600 ºC) × (644.7 in.)

0.000014 x 600 = 0.0084 x 644.7 = 5.42 inches

0.000014 x 610 = 0.00855 x 644.7 = 5.51
Ambient temperature is 22^oC or 72^oF
The beam would have to be heated to 632^oC to expand 5.5 inches

0.000014 x 670 = 0.0094 x 644.7 = 6.05

So the beams would have to be heated to 692^oC to expand 6 inches.

At 600^oC a steel beam loses about half of its strength. Between 600^oC and 692^oC the beams would have sagged as they lost up to 80% of their strength and would start pulling the girder back the other way. The "rock to the east" was NOT the final theory, it was just an interim data gathering test.

The official cause of the girder failure in the final report is: The expanding floor beams pushed a girder off its seat and that started the collapse of WTC 7.

But the beams did not and could not have pushed the girder off its seat.

* * * * *
Attack the argument, not the arguer - Darat

But that guideline is ignored. For those of you who read but do not post, note that no one here will dispute the math or the fact that the beams would sag between 600 and 692^oC. They will continue to attack me rather than the point.

 

[MarkLindeman]

If you mean a minor discrepancy between various revisions of the design drawings and/or what was actually built I don't share your view that it is interesting. Simply situation normal for any engineering project I have been involved with. Revising drawings to what we Aussies call "Work As Executed" and members here call "as built" is driven by several factors. But bottom line is you don't spend money chasing to correct irrelevant minor details. So that is the real world reality. If C7 has you or any others persuaded that this one minor point is of significance I will leave you with that opinion. It does not persuade me.

Not the sort of significance he has in mind. But have we established a discrepancy between the drawings and what was actually built? It could have some bearing on the details of the collapse scenario. I find it interesting more or less in the same way I'm interested in the attempts to identify the chips.

Death spiral for this issue or death spiral for 9/11 conspiracy discussion?

Well, both. I agree with you that this is a minor sideline.

 

[MarkLindeman]

MarkLinderman is asking the same questions over and over so I won't bother responding to him directly again.

I accept your concession, if not your spelling. If you could meet the challenge that I and others have posed to you, you wouldn't be reduced to repeating yourself.

 

[NoahFence]

Because your point is retarded.

 

[ozeco41]

... It could have some bearing on the details of the collapse scenario....

No way!!

... I find it interesting more or less in the same way I'm interested in the attempts to identify the chips.

Your statement is ambiguous as to "it". If you are interested in the minor discrepancy between plan versions So be it. I don't share your interest. It is not unique to the WTC scenario and I don't comprehend how it could be of interest. Likewise If you think it could have any effect on collapse scenario I have the (dis??)advantage of being a structural engineer and therefore I comprehend that it is irrelevant. It is of minor interest that you prefer to go along with C7's nonsense based on his lack of engineering but it's your call as to whether or not you prefer mendacious ignorance over expertise.

I have no problem with people having an interest in anomalies such as chips and microspheres which I recognised in my earlier post. I find that discussion of these side lines tends to cloud the issues of relevance to 9/11 conspiracy related matters. Hence my note about irony in that earlier post which members with over 12 months experience in these threads should be able to interpret.

Cheers

 

[LSSBB]

It is obvious to an objective person that NIST could not have innocently mistaken the notation on the drawings - under Feet/in./16th is 1/0/0 [see post #8]

You still have not answered the question. How is it obvious they could not have been innocently mistaken? How do you KNOW? Do you have some kind of recording of them? Is there a corroborating email that they intended to be deceptive? A confession? Videotape? Mind meld? How do You KNOW?

 

[triforcharity]

He still hasn't shown that the shop drawings were the same as the "as built".

He won't though. He's afraid to answer that.

 

[Christopher7]

He still hasn't shown that the shop drawings were the same as the "as built".

These are the drawings that NIST used for their data and I have already posted that a W33x130 beam [girder] has an 11.5 inch flange and the seat is wider than the flange so your question is moot.

NIST said the seat was 11 inches wide when the plans they were working from said 1 foot.

ETA: Do you have any evidence that there were "as built" drawings at all? If so post it.

Do you understand that the seat was larger than the beam flange?

Can you understand that they would not make the seat smaller than the flange?

 

[LSSBB]

These are the drawings that NIST used for their data and I have already posted that a W33x130 beam [girder] has an 11.5 inch flange and the seat is wider than the flange so your question is moot.

NIST said the seat was 11 inches wide when the plans they were working from said 1 foot.

So? What difference does it make for the outcome?

 

[Christopher7]

So? What difference does it make for the outcome?

http://www.internationalskeptics.com/forums/showpost.php?p=8118232&postcount=3700

 

[triforcharity]

These are the drawings that NIST used for their data and I have already posted that a W33x130 beam [girder] has an 11.5 inch flange and the seat is wider than the flange so your question is moot.

NIST said the seat was 11 inches wide when the plans they were working from said 1 foot.

So, that's a no. Gotcha.

ETA: Do you have any evidence that there were "as built" drawings at all? If so post it.

Nope, but based on personal and professional experience, and the personal and professional experience of many in this thread, and my own personal friends' professional experience, just because the "shop drawings" show one thing, doesn't mean that is what the "as built" plans show.

Do you understand that the seat was larger than the beam flange?

Is that what the bigger number means? No ******* way?!?!?!? Holy ****, my god, I think you're talking math! :Rolleyes:

Can you understand that they would not make the seat smaller than the flange?

You're kidding me.......

 

[000063]

...

,, or an engineer changing the hanging support for two elevated walkways of a hotel lobby (from what the original drawings specified) and failing to notice that this would result in twice the expected stress on the upper walkway's flanges connecting to the supports(resulted in structural failure and people dieing)

Link?

 

[MarkLindeman]

Yeesh, what did I write to deserve this?

It is of minor interest that you prefer to go along with C7's nonsense based on his lack of engineering but it's your call as to whether or not you prefer mendacious ignorance over expertise.

I can only imagine the response if we had a major substantive disagreement.

What I prefer, even in my own field, is when people dial down the harrumphing and walk through their arguments so everyone can tell what they are. The mendacious, willful, or otherwise invincible ignorance tends to come out in the wash.

What, specifically, are you asserting when you deny any relevance to the details of the collapse scenario? That the dimensions of the girder support are irrelevant to whether or when the girder would fall? That whether the girder would fall is irrelevant to whether or when Column 79 would fail? ...?

 

[LSSBB]

http://www.internationalskeptics.com/forums/showpost.php?p=8118232&postcount=3700

Ok, so your saying that the column would have held with 0.5" left to go on the bearing seat?

 

[jaydeehess]

0000063
It was a collapse at iirc a new years eve party in the 80's
originally the rods down from the ceiling supporting the upper and lower walkways were single rods with flanges under each platform. this was changed durin construction.
the uper walk had a rod from ceiling , then another rod , offset from the other between upper and lower walks. flanges were unchanged . however in this confi the flange under the upper walk had to spport the weight of BOTH walkways!
the night o the disaster both walkways were crowded with peoplewatching the lobby below
the upper walk suddenly gaveout both walkways crashed down onto people below

when i am noy forced to post from my kobo I'll search for a link. Can't copy and paste with kobo

 

[GlennB]

It was the Hyatt Regency walkway collapse^WP I believe. Featured in a few TV documentaries.

 

[Tezro]

It was the Hyatt Regency walkway collapse^WP I believe. Featured in a few TV documentaries.

There's also a comprehensive look at the disaster in Matthys Levy and Mario Salvadori's excellent book, "Why Buildings Fall Down".

http://www.amazon.com/Why-Buildings...=sr_1_1?s=books&ie=UTF8&qid=1331999737&sr=1-1

As a non-engineer who works in the building trades, I found this book to be an outstanding and comprehensive covering of the principles behind structural failure. I read it back in college, and I have an old edition of it, so I never saw their chapter on the WTC tower collapses, but I fear it may be somewhat outdated since it preceded the NIST investigations...too bad Salvadori has passed away, a new edition with his contributions on all 3 WTC collapses would be a great resource for the authentically curious layman. Also I've seen his work quote-mined by conspiracists and I wish he were around to defend himself.