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The NIST report, start to finish

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posted on Apr, 29 2011 @ 06:54 PM
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reply to post by -PLB-
 



If you look at the individual members, agreed, if you look at the truss as a single body, then this pure axial stress is the bending stress.

Then why even specify the lower part of the upper chord? The entire upper chord will have a uniform stress in this case. Regardless, this argument is pointless as the truss was not in this mode at any critical point.


Maybe they simply did not though it was necessary? You are now arguing the model is bunk because you did not receive enough information about it for your taste. That is a fallacy.

How can you mistake that for my main argument against this paper? I've already provided calculations proving it bunk. And obviously the internal loads under the configuration causing column failure are more important than the internal loads two weeks before 9/11.


If there is no peer review, the writers can convince me to trust them by showing a respectable background in that area of science.

The writers of the paper we are discussing didn't list their qualifications (if they have them).


Although I am afraid that we will never see anything coming from the truth movement that will be more convincing or trustworthy.

There are some papers here: www.journalof911studies.com...
Although I can't comment on their quality.


We were talking about your claim that if one member fails, the complete truss fails. It seems you are easier satisfied than I am. I do need to see a model that proves this to be the case (and proves the other model to be wrong). I do not believe you on your word/intuition.

It wasn't a claim, it was a generalization. I could provide calculations for a typical case but its not an important point I'm trying to make, more of a passing comment.


You are incorrect because you apply this moment to the top chord only. But it really is nowhere claimed that the situation where the top chord carries all the load is ever reached in their simulation.


It can be seen from Fig 7 that the horizontal
reaction changes in direction from outward to
inward at 11.7 minutes of the standard fire. This
occurs as yielding spreads from mid-span
outwards in the members of the bottom chord.
Once this condition occurs, the moment resistance
of the composite truss, generated by the lever arm
between top and bottom chords, begins to cease to
carry the majority of the load. The load-carrying
mechanism changes progressively to catenary
action, shown in Fig. 8(c), in which both the slab
and top chord carry most of the imposed load in
tension rather than in balanced compression and
tension with the bottom chord.

This is apparently occurring only 11.7 minutes in. This is being modeled by the simulation.


In fact, their simulation stops at the moment there is a local instability. That is the moment the first compressive diagonal fails.

Their simulation definitely modeled catenary action to get their estimated pull-in force. IMO there might be a mistake in the times when they are concluding what happened.




posted on Apr, 29 2011 @ 07:08 PM
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reply to post by -PLB-
 


Alright PLB, you've taken so long to respond I'm assuming you're just ignoring me now.


Remember you said this?:


Originally posted by -PLB-
Note that the claim is not that the pulling force made the columns snap but they buckled as result their loads. The pull force only put them a bit out of place, making the columns more susceptible to buckling.



You are contradicted by NIST's own director, Shyam Sunder, in his own words from the NOVA presentation, as NIcon pointed out:


Originally posted by NIcon
Here's a link to the original presentation:

www.pbs.org...

...

We even get to hear Shyam Sunder explain what we're looking at:

"What then happened after the inward bowing, there was a stage at which the critical amount of inward bowing took place and the columns snapped and essentially the columns, once they snapped, the inwardly bowed columns suddenly sprung back and out."



And I also posted this from NIST's FAQ:


NIST’s findings do not support the “pancake theory” of collapse, which is premised on a progressive failure of the floor systems in the WTC towers (the composite floor system—that connected the core columns and the perimeter columns—consisted of a grid of steel “trusses” integrated with a concrete slab; see diagram below). Instead, the NIST investigation showed conclusively that the failure of the inwardly bowed perimeter columns initiated collapse and that the occurrence of this inward bowing required the sagging floors to remain connected to the columns and pull the columns inwards. Thus, the floors did not fail progressively to cause a pancaking phenomenon.


wtc.nist.gov...



So between these two statements, one some vague wording from NIST's FAQ, the other frank words from the NIST director's own mouth, you must realize by now that yes, this is in fact NIST's hypothesis. No?


The illustration, once again, from the same PBS presentation from which Shyam Sunder spoke... This is NIST's hypothesis:


edit on 29-4-2011 by bsbray11 because: (no reason given)



posted on Apr, 29 2011 @ 07:16 PM
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reply to post by esdad71
 



It is simply the design which if it had columns across the floors as all other buildings, they would have had a better chance.

Kind of like WTC7?

reply to post by hooper
 


There are no experts on both sides of the issue. The so-called experts that propose that the buildings collapsed by any other reason the impact of the planes and the resulting fires are not "experts".

Yet you trust us non-experts to design the structures you occupy.



posted on Apr, 29 2011 @ 08:34 PM
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Originally posted by esdad71
Anok,

OK, so you show a video also that shows that the top is falling separately from the bottom at the point of the airline impacts.


Yes that was kinda the point. If the top is collapsing separately from the bottom then it is two events and the first one did not cause the second one.


Also, pancake and progressive are two separate things....


Actually no they're not. Pancake collapse is a type of progressive collapse.


2. Types of progressive collapse

2.1 Pancake-type collapse

This type is exemplified by the collapse of the World Trade Center (WTC) towers...


www.tu-harburg.de...


...it was a progressive collapse based on a few factors, not one. It did not simply fall at free fall speeds and destroy the building. In the end, the cores and the outer columns of lower floors were still there on both towers.


And your point is?


It is simply the design which if it had columns across the floors as all other buildings, they would have had a better chance. Not that it is incorrect or faulty but it was not designed for what happened.


Nonsense. You make claims like you know what you're talking about, but I am constantly having to show you where you misunderstand the physics involved in the collapse of a building.

You must think engineers are stupid and have no idea what they're doing. You also make a huge assumption that you seem to think everyone agrees with you that falling floors can cause a complete PANCAKE collapse of a 110 story building, with your magic KE that increases, instead of decreases, when met with friction/resistance.
You assume that the buildings collapses was inevitable, and the actual collapse isn't in question but how it was initiated. The whole collapse scenario is in question.


I am not stopping at initation.Once we agree on the initiation then it is time to talk collapse.


Why would we ever agree on the initiation, when I don't believe plane impacts, fires, sagging trusses etc., could cause an initiation in the first place? I often make this point and you ignore that also, so really you are arguing the initiation of the initiation. You stop at initiation because you have no idea how to debate the actual collapses without struggling and looking stupid, safer to argue what NIST covered, at least you can appeal to that authority to save face.


edit on 4/29/2011 by ANOK because: for your pleasure



posted on Apr, 29 2011 @ 08:57 PM
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reply to post by bsbray11
 


If you want to know what NIST says the best approach it to read their reports.


Floor sagging and exposure to high temperatures caused the exterior columns to bow inward and buckle—a process that spread across the faces of the buildings.



posted on Apr, 29 2011 @ 09:09 PM
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Originally posted by -PLB-
reply to post by bsbray11
 


If you want to know what NIST says the best approach it to read their reports.


Floor sagging and exposure to high temperatures caused the exterior columns to bow inward and buckle—a process that spread across the faces of the buildings.


Hello! Are you awake in there?

I think bsbray knows what NIST is claiming, better than you in fact.

Do you support the NOVA representation of the NIST report, or not?

Personally I'm new to the NOVO doco and am quite amazed to find that the claims are more bizarre than I ever thought. If I had seen that when it came out I would have saved my time with all these posts and just put that pic up with a big ROTFLMAO, debate over. No one could take that seriously, well except you lot lol.



posted on Apr, 29 2011 @ 09:23 PM
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Originally posted by Azp420
Then why even specify the lower part of the upper chord? The entire upper chord will have a uniform stress in this case. Regardless, this argument is pointless as the truss was not in this mode at any critical point.


That is why I talked about 2 distinct situations, one where the compressive diagonals are intact (and the truss can be seen as one body), and one where they failed (and bending stress in individual chords starts playing a role). Anyway lets just drop this, I don't think its relevant to any argument.


How can you mistake that for my main argument against this paper? I've already provided calculations proving it bunk. And obviously the internal loads under the configuration causing column failure are more important than the internal loads two weeks before 9/11.


And I disagree with your argument.


The writers of the paper we are discussing didn't list their qualifications (if they have them).


"Department of Civil and Structural Engineering, University of Sheffield" does the trick for me. If you give me reason to doubt their qualification, I may further investigate. Better yet, show they are not qualified.


There are some papers here: www.journalof911studies.com...
Although I can't comment on their quality.


I have read some of them, but never really found anything compelling. If you can recommend me one, I would be interested to read it.




It can be seen from Fig 7 that the horizontal
reaction changes in direction from outward to
inward at 11.7 minutes of the standard fire. This
occurs as yielding spreads from mid-span
outwards in the members of the bottom chord.
Once this condition occurs, the moment resistance
of the composite truss, generated by the lever arm
between top and bottom chords, begins to cease to
carry the majority of the load. The load-carrying
mechanism changes progressively to catenary
action, shown in Fig. 8(c), in which both the slab
and top chord carry most of the imposed load in
tension rather than in balanced compression and
tension with the bottom chord.


This is apparently occurring only 11.7 minutes in. This is being modeled by the simulation.

Their simulation definitely modeled catenary action to get their estimated pull-in force. IMO there might be a mistake in the times when they are concluding what happened.


There is definitely catenary action in their simulation. But during the time there is catenary action, all truss members are still intact, so the truss should be able to hold as it is designed to do. That means your calculations do not apply to the model, and you have not to proved it to be wrong.



posted on Apr, 29 2011 @ 09:26 PM
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reply to post by ANOK
 


I don't see how NOVA contradicts the report. It nowhere says that the pull force made the columns snap. It say the pull force made the columns bow inward which made them snap, just like the report, And if you have a problem with that image then, well, whatever. If thats all you got against NIST, I guess you pretty much agree with their conclusions.



posted on Apr, 29 2011 @ 10:17 PM
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Originally posted by -PLB-
If you want to know what NIST says the best approach it to read their reports.


Floor sagging and exposure to high temperatures caused the exterior columns to bow inward and buckle—a process that spread across the faces of the buildings.


By no account is that all that happened, even hypothetically.

If NIST's own lead investigator during the WTC investigations doesn't even understand his agency's own hypothesis, according to you... Well you already get the picture, whether you want to admit it or not. You cannot reinvent their report in your own image. I'm sorry.



Dr. Shyam Sunder was NIST's "lead investigator" during their WTC "investigation."

And again this is what he himself says:

"What then happened after the inward bowing, there was a stage at which the critical amount of inward bowing took place and the columns snapped and essentially the columns, once they snapped, the inwardly bowed columns suddenly sprung back and out."


Did you watch NIST's presentation with PBS? www.pbs.org...

That is Shyam Sunder speaking himself.



posted on Apr, 29 2011 @ 10:21 PM
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Originally posted by -PLB-
I don't see how NOVA contradicts the report. It nowhere says that the pull force made the columns snap. It say the pull force made the columns bow inward which made them snap, just like the report, And if you have a problem with that image then, well, whatever.


Good God... now you've done a complete 180 on your position on the last page, and then again even within two sentences of each other. Your "argument" has become so convoluted, this is priceless stuff.


You say....

"It nowhere says that the pull force made the columns snap"

and then you say....

"It say the pull force made the columns bow inward which made them snap."

On the last page you were arguing that the PBS image was not accurate with the NIST report, now you realize there is no contradiction... And you act like we're the ones arguing that there is? No, we already knew that!!


I guess when you finally realize that the NIST report is complete garbage, you'll start pretending you were a "truther" all along too.




On page 10 you said:


Originally posted by -PLB-
Note that the claim is not that the pulling force made the columns snap but they buckled as result their loads. The pull force only put them a bit out of place, making the columns more susceptible to buckling.


But I got ya now.... The claim is not that the pulling force made the columns snap, but rather that the pulling force made the columns snap.

Ohhhhhhh okay I gotcha.


Yeah, wink wink nudge nudge, you were right all along huh.

edit on 29-4-2011 by bsbray11 because: (no reason given)



posted on Apr, 29 2011 @ 10:56 PM
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reply to post by bsbray11
 


I will try to put it really simple again for you.

Wrong:
Pull -> Snap

Correct:
Pull -> Bow -> Snap

Notice the additional word. Oh well, who am I kidding.



posted on Apr, 29 2011 @ 11:05 PM
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Originally posted by -PLB-
reply to post by ANOK
 


I don't see how NOVA contradicts the report. It nowhere says that the pull force made the columns snap. It say the pull force made the columns bow inward which made them snap, just like the report, And if you have a problem with that image then, well, whatever. If thats all you got against NIST, I guess you pretty much agree with their conclusions.


So what?

I don't have to listen to what they said to know there is no explanation possible for what they're representing in that doco, shown in the still posted. It's complete nonsense no matter how they try to explain it. Not only can sagging trusses not put a pulling force on the columns, they most certainly can not make the column snap in those two places, ignoring weaker points in the system. And we're supposed to believe that happened to all the independent trusses at the same time?

Try doing that in any way you wish, you will not get it to work. It's an untestable hypothesis not even based on common sense.

It's a complete face slap moment mate. Seriously.

Edit;


Wrong:
Pull -> Snap

Correct:
Pull -> Bow -> Snap

Notice the additional word. Oh well, who am I kidding.


You are kidding aren't you? You have to be.


edit on 4/29/2011 by ANOK because: for your pleasure



posted on Apr, 29 2011 @ 11:21 PM
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Something I just thought of, how come none of you OSers claim that the planes took out any floor trusses?

Is that because if it did that would contradict the whole truss failure leads to inevitable complete global collapse hypothesis?

Just curious because that seems like the sort of thing that OSers would claim, like you used to claim the planes severed core columns. Not heard that one for a while, was it dropped, or is that still being supported?

Core columns were severed but lightweight floor trusses were not? Don't forget the pains the OSers went to to emphasis lightweight trusses.

The contradictions abound...


edit on 4/29/2011 by ANOK because: i love the sound of my typing



posted on Apr, 29 2011 @ 11:26 PM
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Originally posted by -PLB-
I will try to put it really simple again for you.

Wrong:
Pull -> Snap

Correct:
Pull -> Bow -> Snap

Notice the additional word. Oh well, who am I kidding.


Yeah, who are you kidding?


Since you're making this into a joke anyway, you totally left out the creaking noise stage:

Pull -> Bow -> Creaking Noise -> Snap


Oh yeah and I almost forgot, the exploding in all directions:

Pull -> Bow -> Creaking Noise -> Snap -> Explode in all directions


Oh yeah, and "profit":

Pull -> Bow -> Creaking Noise -> Snap -> Explode in all directions -> Profit from War


Come on man, give it up. You were just arguing with me on the last page that the PBS stuff was inaccurate. Now you've changed your tune completely. Don't play stupid like you've been arguing this the whole time. You'd get more respect if you were just straightforward about it.



posted on Apr, 30 2011 @ 03:08 AM
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Originally posted by bsbray11

Originally posted by -PLB-
I will try to put it really simple again for you.

Wrong:
Pull -> Snap

Correct:
Pull -> Bow -> Snap

Notice the additional word. Oh well, who am I kidding.


Yeah, who are you kidding?


Since you're making this into a joke anyway, you totally left out the creaking noise stage:

Pull -> Bow -> Creaking Noise -> Snap


Oh yeah and I almost forgot, the exploding in all directions:

Pull -> Bow -> Creaking Noise -> Snap -> Explode in all directions


Oh yeah, and "profit":

Pull -> Bow -> Creaking Noise -> Snap -> Explode in all directions -> Profit from War


Come on man, give it up. You were just arguing with me on the last page that the PBS stuff was inaccurate. Now you've changed your tune completely. Don't play stupid like you've been arguing this the whole time. You'd get more respect if you were just straightforward about it.


Bsb you forgot a few elements....

Pull -> Bow -> Creaking Noise -> Snap -> Explode in all directions -> 80% of debris ejected out of the towers footprint -> Causing air to compress and behave like squibs -> Profit from War.

There we go

edit on 30-4-2011 by Seventh because: (no reason given)



posted on Apr, 30 2011 @ 03:41 AM
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reply to post by Seventh
 


Right, but the point is that we just came out of 2 or 3 pages of discussion as to this "pull" force NIST alleges deflected the columns, etc., and PLB had just posted this a couple thread pages ago:


Note that the claim is not that the pulling force made the columns snap but they buckled as result their loads. The pull force only put them a bit out of place, making the columns more susceptible to buckling.


According to his own infallible reasoning of "if you leave a word out then you're wrong," then he must have really been talking out of his ass when he said "the claim is not that the pulling force made the columns snap" and then completely failed to mention anything else about columns being pulled out according to NIST. The truth is that he automatically assumed the PBS image and description by Shyam Sunder was wrong, because even he must have realized how ridiculous they were at first, but then once he was forced to cope with the fact that this really is what NIST is getting around at, he started putting on like this is what he was saying the whole time, with the ridiculous posts above. And whoever gave him those two stars, must have just felt sorry for him.


At least we are all finally in agreement that this is NIST's hypothesis:




I don't think I would be too far off base in assuming that most people posting on this thread would agree that the truss connections would fail much sooner that the column would experience failures at both its bolts and spandrel plate connections, assuming a great enough force could ever be exerted horizontally in the force place (no evidence for this). Here is what the trusses actually looked like connected to the perimeter columns:




And considering the intellectual dishonesty that was just hilariously demonstrated above, I wonder what point there would even be in asking what evidence NIST actually offered for this mechanism.

edit on 30-4-2011 by bsbray11 because: (no reason given)



posted on Apr, 30 2011 @ 06:04 AM
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Originally posted by Seventh
Bsb you forgot a few elements....

Pull -> Bow -> Creaking Noise -> Snap -> Explode in all directions -> 80% of debris ejected out of the towers footprint -> Causing air to compress and behave like squibs -> Profit from War.

There we go

edit on 30-4-2011 by Seventh because: (no reason given)

I specifically asked for this utter idiocy to be kept out of this thread.

Please take your childish ganging up on a poster elsewhere. You are wrong and he is correct, and once again you have shown your desire to twist evidence to your favour. What sort of illogical proposition is it that you are trying to show the NIST report is wrong with your disagreement over an animation provided by a third party?

Azp you have provided an excellent debate in this thread, and while I do think you are wrong I can't easily prove it in a few sentences. We have a 4 day weekend over here so hopefully I will find the time, if not I will respond to you early next week.

Really sorry about this but I can only snatch a few minutes at a time at the moment. Cheers.



posted on Apr, 30 2011 @ 09:33 AM
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reply to post by psikeyhackr
 


Still standing means they are still standing. Not the entire buildings but the core and outer columns, you know, the ones you keep saying where crushed along with all of your concrete.

This thread seems to be about being able to give stars to friends rather than keeping up a good conversation.



posted on Apr, 30 2011 @ 09:56 AM
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reply to post by ANOK
 


I have explained, posted pictures and videos that show how the core columns were severed. There are accounts from survivors.You cannot argue that there were no columns were severed. Not all, I believe less than 10% severed and 25% damaged. The south tower had most of the damage to one corner of the inner core. The north was more to the center.

When this happens, the bulk of the load would transfer to the outer columns. It has to transfer somewhere. This is where the sagging trusses of multiple floors comes into play also. There are plenty of pictures of this.If it is trying to compensate for the inner columns damage as well as being bowed by the sagging floors it is no longer stable.



posted on Apr, 30 2011 @ 10:18 AM
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reply to post by exponent
 

It's not just the animation. I specifically went back and added the quote from Shyam Sunder so this claim could not be made. And there is more that he said if anyone cares to look at the transcript.

So why did the Active Leader of the NIST Investigation make this presentation? Is he considered a third party?

If this is the position of the NIST Investigation, why is this "critical amount of inward bowing" never examined in the report? Where is the measurement of this "critical amount" to differentiate it from a non-critical amount? Where is the examination of this "snapping" of columns? He makes pretty darn clear this is what happened before the top "started moving downward."

If this is not the position of the NIST Investigation, then why is, at the time, the active leader of the NIST Investigation presenting this as a certainty? Did he come to the wrong conclusion of the very same report he lead? Should we yell and scream that Shyam is out spreading "disinformation" like I see so many on here accusing the "conspiracy" sites of doing?




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