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ZELDAR

Empire State Building VS WTC

88 posts in this topic

There are a number of engineers who disagree with AE911:

http://www.era.lib.ed.ac.uk/bitstream/1842/1216/1/WTCpaper.pdf

http://www.arup.com/_assets/_download/download353.pdf

http://www.royalsoced.org.uk/events/reports/2003-2004/fire_structures.pdf

http://www.kz.tsukuba.ac.jp/~isobe/wtc-e.html

http://www.icivilengineer.com/News/wtc.php

http://www.tms.org/pubs/journals/JOM/0711/banovic-0711.html

There is also the Purdue computer modeling:

http://www.cs.purdue.edu/homes/cmh/simulation/phase4/index.html

See also:

What Did and Did not Cause Collapse of WTC Twin Towers in New York

Authors Bazant, Le, Greening & Benson. Journal of Engineering Mechanics ASCE 134 (2008).

Mechanics of Progressive Collapse: Learning from World Trade Center and Building Demolitions Co-author Verdure. PDF. Journal of Engineering Mechanics ASCE 133 (2007): pp. 308–319

Discussion and replies to June 2006 Bazant & Verdure paper: James Gourley, G. Szuladinski

Bazant & Zhou, 2001-2002: Why Did the World Trade Center Collapse?—Simple Analysis J. Engineering Mechanics ASCE, Sept. 28, 2001, addendum March, 2002.

Why Did the World Trade Center Collapse? Science, Engineering, and Speculation. Eagar, T.W., & Musso, C., JOM v. 53, no. 12, (2001): 8-12.

Dissecting the Collapses Civil Engineering ASCE v. 72, no. 5, (2002): 36-46.

A suggested cause of the fire-induced collapse of the World Trade Towers. By: Quintiere, J.G.; di Marzo, M.; Becker, R.. Fire Safety Journal, Oct2002, Vol. 37 Issue 7, p707, 10p.

S. W. Banovic, T. Foecke, W.E. Luecke, et al. “The role of metallurgy in the NIST investigation of the World Trade Center towers collapse”, JOM, vol. 59, no. 11, pp. 22-29, November 2007.

Impact of the Boeing 767 Aircraft into the World Trade Center. By: Karim, Mohammed R.; Fatt, Michelle S. Hoo. Journal of Engineering Mechanics, Oct2005, Vol. 131 Issue 10, p1066-1072.

Could the world trade center have been modified to prevent its collapse?; Newland, D. E.; Cebon, D. Journal of Engineering Mechanics; 2002 Vol. 128 Issue 7, p795-800, 6p.

"Elaboration on Aspects of the Postulated Collapse of the World Trade Centre Twin Towers" Clifton, Charles G., HERA: Innovation in Metals. 2001. 13 December 2001.

How the airplane wing cut through the exterior columns of the World Trade Center; Wierzbicki, T.; Teng, X. International Journal of Impact Engineering; 2003 Vol. 28, p601-625, 25p

Stability of the World Trade Center Twin Towers Structural Frame in Multiple Floor Fires. By: Usmani, A. S.. Journal of Engineering Mechanics, Jun2005, Vol. 131 Issue 6, p654-657.

Structural Responses of World Trade Center under Aircraft Attacks. Omika, Yukihiro.; Fukuzawa, Eiji.; Koshika, Norihide. Journal of Structural Engineering v. 131 no1 (January 2005) p. 6-15

The Structural Steel of the World Trade Center Towers. Gayle, Frank W.; Banovic, Stephen W.; Foecke, Tim. Advanced Materials & Processes v. 162 no10 (October 2004) p. 37-9

WTC Findings Uphold Structural Design. Post, Nadine M. ENR v. 253 no17 (November 1 2004) p. 10-11

"World Trade Center Collapse-Civil Engineering Considerations" Monahan, B., Practice Periodical on Structural Design and Construction v. 7, no. 3, (2002): 134-135.

Ming Wang, Peter Chang, James Quintiere, and Andre Marshall "Scale Modeling of the 96th Floor of World Trade Center Tower 1" Journal of Performance of Constructed Facilities Volume 21, Issue 6, pp. 414-421

Engineering Conference Papers

"TMS Hot Topic Symposium Examines WTC Collapse and Building Engineering" Marechaux, T.G. JOM, v. 54, no. 4, (2002): 13-17.

Abboud, N., M. Levy, D. Tennant, J. Mould, H. Levine, S. King, C. Ekwueme, A. Jain, G. Hart. (2003) Anatomy of a Disaster: A Structural Investigation of the World Trade Center Collapses. In: Proceedings of the Third Congress on Forensic Engineering. San Diego: American Society of Civil Engineers. pp 360-370

Beyler, C., D. White, M. Peatross, J. Trellis, S. Li, A. Luers, D. Hopkins. (2003) Analysis of the Thermal Exposure in the Impact Areas of the World Trade Center Terrorist Attacks. In: Proceedings of the Third Congress on Forensic Engineering. San Diego: American Society of Civil Engineers. pp 371-382

Thater, G. G.; Panariello, G. F.; Cuoco, D. A. (2003) World Trade Center Disaster: Damage/Debris Assessment In: Proceedings of the Third Congress on Forensic Engineering. San Diego: American Society of Civil Engineers. pp 383-392

Edited by Obviousman

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what messed me up was the night before the wtc building attack, pbs did a doc on the b-25 hitting the empire state building. so the next day when i first heard about the wtc i thought they were talking about the show i had seen the night before. i hadnt turned on the news.

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The WTC builders did think it could happen. The towers shouldn't have collapsed at all, much less in the way they did.

Car builders know that accidents happen. There should be no fatal car accidents.

No further comment necessary...

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Please see the message board rules, “2d. Accuracy: Do not post material that is knowingly or intentionally false, inaccurate or misleading.”

Also worthy of note are the Beijing Television Cultural Center fire, the Caracas Tower fire, the Windsor Madrid building fire, the Cardington Test building fire, the Bankers Trust building fire and the WTC5 fire. Not one of these examples came close to the results of the three WTC buildings on 9/11. The only evident comparison for that…… is controlled demolition.

Which of these buildings was hit by an airplane? Isn't it false and misleading to omit this simple fact?

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The WTC builders did think it could happen. The towers shouldn't have collapsed at all, much less in the way they did.

Have you read anything here?

Like the post before yours?

We designed the towers to resist the accidental impact of a Boeing 707, perhaps lost in the fog while seeking to land. The impact of the Boeing 767s, commandeered by the terrorists, even though larger and flying much faster, was still unable to bring down the towers. The fire-resistive systems, however, did not and could not have contemplated the subsequent fire fueled by thousands of gallons of jet fuel.

Which of these buildings was hit by an airplane? Isn't it false and misleading to omit this simple fact?

Yes....

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There are a number of engineers who disagree with AE911:

There is as much disagreement between the papers you posted as anything else. I’m not just saying that for the fun of it – read them, they cannot agree on much and show outright conflict in places.

The first paper you linked remarks that Quintiere’s theory is “improbable”.

Quintiere himself has left his disdain for the NIST investigation in no doubt.

The NIST impact analysis does not corroborate that of Purdue.

And so on.

They struggle to come up with a cohesive theory in support of the official story. In the background to this squabbling and uncertainty, 1,258 independent architects and engineers demand a thorough and unbiased investigation to determine the true cause. If there were nothing untoward then there is no reason to be afraid of this.

Edit: it is now 1,262 - another four qualified individuals have signed the petition.

Which of these buildings was hit by an airplane? Isn't it false and misleading to omit this simple fact?

You are omitting WTC7 which did not suffer an impact.

Apart from that, the WTC impact damage is too often over-hyped and it is still possible to make comparisons with severe high-rise fires in steel-framed buildings all as I have described above.

Edited by Q24

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You are omitting WTC7 which did not suffer an impact.

Apart from that, the WTC impact damage is too often over-hyped and it is still possible to make comparisons with severe high-rise fires in steel-framed buildings all as I have described above.

WTC7 did suffer an impact...large portions of WTC1 falling into it, creating a large (witness reported) hole in the front of the building. As for the WTC1&2 aircraft impact damage...it severed support beams, external and core beams. It stripped fireproofing from large areas of supporting steel. The fires you compare it to had no such structural damage and exposed steel due to impacts. I still see it as a false analogy.

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There is as much disagreement between the papers you posted as anything else. I’m not just saying that for the fun of it – read them, they cannot agree on much and show outright conflict in places.

Check the dates, most of the conflicting theories come soon after 9/11. Once the NIST report is issued it seems to have put most of the controversy to rest.

What all the papers, pre and post NIST, are agreed on is that no explosives are needed. How does the fact that engineers can come up with several different non-explosive collapse scenarios help your case that it must have been explosives? This just shows that non-explosive collapse isn't nearly as unlikely as you claim.

Edited by flyingswan

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WTC7 did suffer an impact...large portions of WTC1 falling into it, creating a large (witness reported) hole in the front of the building.

The debris damage was superficial in this respect, i.e. had no bearing whatsoever to the onset of global collapse.

With this in mind, the building fires I gave examples of are more than comparable to the WTC7 situation.

It may be of benefit to read the NIST report on WTC7.

They would have us believe that the building imitated a controlled demolition due to the loss of only one column beginning a chain reaction of failures which completed in a matter of seconds. Further, that this would be the case irrespective of surrounding fire and/or damage. They admit there was no heat induced weakening of the columns or redistribution of the building loads worthy of note (prior to that one all important column being pushed off centre). It was this single column that the entire structure relied upon according to NIST, damage and fire or not.

Sorry but they don’t design buildings that way.

I wouldn’t design a shed to be this vulnerable, much less a skyscraper.

Does it honestly appear realistic to you?

As for the WTC1&2 aircraft impact damage...it severed support beams, external and core beams. It stripped fireproofing from large areas of supporting steel. The fires you compare it to had no such structural damage and exposed steel due to impacts. I still see it as a false analogy.

I described in my post #24 how the structural damage was not decisive; there remained huge reserve capacity in the cores following the airliner impacts (more than in many buildings which are wholly intact). It is of course true that areas of fireproofing would be removed during the impact, though in the other building fire examples this had also been removed or the fire rating had been exceeded so making the comparison still appropriate.

Look at the One Meridian Plaza fire over the page again. Why is it that this building can sustain significant structural damage with large deformation of the steelwork and remain intact, whereas pushing a single column out of place in WTC7 or a sagging floor in WTC1 leads to global collapse?

The difference in behaviours is startling.

The official collapse theory is so outlandish next to all known precedent as to be unreal.

There are now 1,263 architects and engineers who would also lean that way.

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It may be of benefit to read the NIST report on WTC7.

It would be of more benefit to you if you showed any ability to understand it. The collapse wasn't just "one column", it started with one column which lost its supporting structure due to thermal expansion breaking joints, but the surrounding columns would also be in a weakened state due to similar loss of supporting structure. In other words, the fact that the fire lasted so long with no attempt at control led to a lot of damage, and it was because of this fire-induced damage that the eventual failure of a single column brought down the surrounding columns as well.

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It would be of more benefit to you if you showed any ability to understand it. The collapse wasn't just "one column", it started with one column which lost its supporting structure due to thermal expansion breaking joints, but the surrounding columns would also be in a weakened state due to similar loss of supporting structure. In other words, the fact that the fire lasted so long with no attempt at control led to a lot of damage, and it was because of this fire-induced damage that the eventual failure of a single column brought down the surrounding columns as well.

I see, so you are saying that without the wider “lot of [fire] damage” causing the “surrounding columns” and “supporting structure” to be in a “weakened state”, the failure of column 79 on its own would not have led to progressive and ultimately global collapse?

I got the impression NIST were saying that if that column alone failed then it would lead to the whole house of cards tumbling down. Well I did think it was quite an absurd idea that the entire building relied entirely on a single column and you seem to agree. Other weakening from the fire in addition to the failure of column 79 would have been necessary to produce the witnessed collapse – we are on the same page here?

If this is the case then it does make more sense I guess.

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I see, so you are saying that without the wider “lot of [fire] damage” causing the “surrounding columns” and “supporting structure” to be in a “weakened state”, the failure of column 79 on its own would not have led to progressive and ultimately global collapse?

Exactly.

I got the impression NIST were saying that if that column alone failed then it would lead to the whole house of cards tumbling down. Well I did think it was quite an absurd idea that the entire building relied entirely on a single column and you seem to agree. Other weakening from the fire in addition to the failure of column 79 would have been necessary to produce the witnessed collapse – we are on the same page here?

Yes.

For instance, look at Fig 3.9 in the NIST report, showing the predicted progression of the fire damage prior to the collapse.

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So I was reading an article about the Empire State Building having bedbugs in its basement. I noticed it said it withstood a B-52 Bomber crashing into it at 200 mph. So, how could a building built in 1931 be made to take a hit from a plane, and the World Trade Centers went down after 56 minutes? All of these buildings (WTC) were built between 1975 and 1981. Surely the architects would have built it with the ability to withstand multiple plane crashes at over 200 mph and more weight. I mean... it was almost 50 years later. If this doesn't prove that there were explosives in the damn buildings, and that this was an inside job. WTF does? Also don't know if this should be posted here but it seems like a modern mystery to me.

IMO... I don't think the ESB getting hit with a plane does anything for the WTC theories..

The ESB is made of serious amount of rock and concrete with steel support, with little bits of glass inserted for windows.

The TWC was made of steel framing and pretty much sheathed in glass, in a design meant to sway a bit for high winds.

I would expect that the ESB is sturdily enough made to be able to take a hit... I would also expect a skyscraper like the WTC not to be able to take a hit.

There's a bit of truth to the saying "We just don't build them like we used to."

And besides, several thousand gallons of jet fuel is sure gonna make a far more serious fire than any builder would account for..

Edited by rashore

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Exactly.

Yes.

Have you any idea how badly you just trashed NIST’s WTC7 model?

You don’t get it do you.

NIST simulated four scenarios, varying the fire/debris impact damage in each. In the final simulation, NIST left out this damage altogether and removed only that single column 79 – the rest of the building remained fully intact. The relevant text: -

pg. 39

  • In the fourth simulation, the building experienced no debris or fire-induced damage. A section of Column 79 between Floors 11 and 13 was removed. The purpose of this analysis was to determine the potential for a classic progressive collapse, i.e.,
    disproportionate structural damage from a single failure
    , regardless of the cause of that failure.

pg. 42

  • The fourth LS-DYNA analysis showed that, following the removal of Column 79 between Floors 11 and 13, vertical and horizontal progression of failure occurred. This was followed by downward movement at the roofline due to buckling of exterior columns, which led to the collapse of the entire building. This analysis showed that WTC 7 was prone to classic progressive collapse associated with the local failure of Column 79.

You see, NIST do absolutely claim that the failure of that one column alone would lead to the whole house of cards tumbling down, no debris or fire induced damage involved. So that is where I got the impression from, I don’t just make these things up you know, there is more often than not a source involved.

Now, you just firmly asserted that the above result is not possible to obtain in your opinion.

It was necessary for the surrounding columns to be in a weakened state, you said.

The failure of column 79 on its own would not have led to collapse, you confirmed.

The idea of the building relying entirely on a single column was absurd, you agreed.

I do completely agree with you in these points.

And so here we are, your own opinion is in complete conflict with NIST on this specific issue – you say that the single failure is not enough to bring the entire structure down and they say that it is. Don’t forget, I’m right with you in agreement on this one. But now here’s the test for us… what are we going to do? There are two choices: to hold firm in our conviction or to forget what we know and fall meekly in line with what the authority figure dictates to us is ‘right’. Heck I already know which way each of us is going to go.

Still, for a moment at least you showed that NIST produced results deemed impossible by an engineer.

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The plane that hit the Empire State Buildng wasn't a Boeing 757 (correct me if I'm wrong about the number) and not going at high fast speed. And the building was still unoccupied. The plane didn't have the fuel like the planes that hit the towers. Not to mention that the plane was much MUCH smaller than the two 9/11 planes.

When the towers went up, no one thought THAT could happen. It's not like people could see the future or anything.

Actually when the twin towers were constructed they originally had anti aircraft guns on the roof.

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So I was reading an article about the Empire State Building having bedbugs in its basement. I noticed it said it withstood a B-52 Bomber crashing into it at 200 mph. So, how could a building built in 1931 be made to take a hit from a plane, and the World Trade Centers went down after 56 minutes? All of these buildings (WTC) were built between 1975 and 1981. Surely the architects would have built it with the ability to withstand multiple plane crashes at over 200 mph and more weight. I mean... it was almost 50 years later. If this doesn't prove that there were explosives in the damn buildings, and that this was an inside job. WTF does? Also don't know if this should be posted here but it seems like a modern mystery to me.

Just asking but didn't a B-25 bomber hit it durring a heavy fog as opposed to a B-52? I might be wrong, and if so, I do apologize for my error.

Edited by Graveyard Hound

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Have you any idea how badly you just trashed NIST’s WTC7 model?

You don’t get it do you.

NIST simulated four scenarios, varying the fire/debris impact damage in each. In the final simulation, NIST left out this damage altogether and removed only that single column 79 – the rest of the building remained fully intact.

You do realise that removing a column over two floors means that you also have to remove the stabilising effect of the intermediate floor beams on the surrounding columns?

No, you obviously don't. They may be removing the predicted fire-damage, but they are adding in equivalent extra damage none-the-less.

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IMO... I don't think the ESB getting hit with a plane does anything for the WTC theories..

The ESB is made of serious amount of rock and concrete with steel support, with little bits of glass inserted for windows.

The TWC was made of steel framing and pretty much sheathed in glass, in a design meant to sway a bit for high winds.

Actually, they're all built to sway in the wind.

I would expect that the ESB is sturdily enough made to be able to take a hit... I would also expect a skyscraper like the WTC not to be able to take a hit.

Actually, they were both quite capable of taking a hit.

And besides, several thousand gallons of jet fuel is sure gonna make a far more serious fire than any builder would account for..

Fire was the significant accelerant on 9-11. However, if the fire could've been extinguished in a reasonable amount of time, odds are the buildings probably would've stood (although you'd be hard pressed to get me inside one of them!).

But you're absolutely correct. There's no correlation between the B-25 impact on the ESB and the 767 impacts on the WTC towers on 9-11-01. Absolutely no relevant comparison.

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Just asking but didn't a B-25 bomber hit it durring a heavy fog as opposed to a B-52? I might be wrong, and if so, I do apologize for my error.

No you're correct. It was a B-25 in low visibility conditions, and at relatively low speed. The B-52 hadn't been developed yet at that time.

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Actually, they're all built to sway in the wind.

Correct. It's called sheer strength. That's the reason framers stager the joints on the plywood when sheeting a roof with plywood. (But the exterior walls on the WTC's were a much larger scale)
Actually, they were both quite capable of taking a hit.

Multiple hits actually. The buildings were designed to redistribute their load in times of crises. At least that's what I gathered from the architects. Personally, I thought it was a sound design, using the core columns to support appr. 85% of the load and the exterior to handle the sheer strength.

Fire was the significant accelerant on 9-11. However, if the fire could've been extinguished in a reasonable amount of time, odds are the buildings probably would've stood (although you'd be hard pressed to get me inside one of them!).

But you're absolutely correct. There's no correlation between the B-25 impact on the ESB and the 767 impacts on the WTC towers on 9-11-01. Absolutely no relevant comparison.

Here's where we differ. If we're talking 47 "four inch wall" steel box beams, not aluminum aircraft parts nor fire will touch them. If they were compromised it was by the explosion, most of which happened outside. But it still would have been one heck of a shock wave. Was it enough? I don't know, but the fire theory needs to go to the rubbish bin.

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I would like to add to this conversation by asking a simple question.

Did any model account for Friction?

The full weight of a 747 hitting the building at high speeds is probably enough to shoot the degree's up by a good number.

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The full weight of a 747 hitting the building at high speeds is probably enough to shoot the degree's up by a good number.

Overall, a rather small number compared with the effects of burning the aviation fuel and the contents of the building. However, there will be places where this energy is concentrated into small volumes, and this is significant for generating local hotspots. In other words, it helps to start the fires but doesn't add a lot to the total fire damage.

Edited by flyingswan

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the plane that hit the ESB was a lot smaller than hit the WTC towers at est 600 mph.

it was also loadsed with fuel!

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Here's where we differ. If we're talking 47 "four inch wall" steel box beams, not aluminum aircraft parts nor fire will touch them.

If you're talking about "four inch wall" box columns, you're way off. The column wall thickness was tapered from a couple inches at the foundation to a quarter inch on the upper floors.

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If you're talking about "four inch wall" box columns, you're way off. The column wall thickness was tapered from a couple inches at the foundation to a quarter inch on the upper floors.

You're right when you say they tapered, but I would love to see the engineering were they used quarter wall for the main support in a skyscraper even at the tip top of the building. And the thickness at the base was 4"s. I'm a bit surprised at your info. It's been a long time time since I've seen the prints so could you point me in the direction where you found this?

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