WTC 1 & 2. What happened after collapse initiation?

"Al Qaeda" had already allegedly bombed the Towers ( allegedly with a little help from the FBI)

You wrong on both accounts. Ramzi Yousef had no connections to Al Qaeda in 1993. While he received money for the attacks from his uncle, Khaled Shaikh Mohammed, the planner of 9/11, at the time KSM had no connections to Al Qaeda either. Yousef was looking at linking up with AQ at the time of his capture and KSM would join up with AQ later. Most of the crew that Yousef used for the bombing was associated with Sheikh Omar Abdel-Rahman, otherwise known as the Blind Sheikh, though it appears that while he was indeed a militant who likely would have approved of such actions, he was not directly involved in the bombing either.

In the accounts of the FBI involvement, these stem from the actions of Emad Salem, an FBI informant that initailly was recruited and worked with the bombers. Emad believed that he was being used in an FBI sting, but the higher ups in the FBI believed that he was merely stringing them along for more and more money. They finally cut off his expenses in January of 1993 when he claimed that the group was moving and he needed more money to go with them. The FBI refused believing he wasn't telling the truth and subsequently Emad left the bombers' group and stopped informing to the FBI. After the bombing he was rehired and started workin on a new group, but once more the FBI started to distrust him leading to his recording conversations with his handlers complaiming about the way he was being treated and his belief that another 93 bombing incident was likely because last time he was disbelieved he'd been reporting to the FBI everything that had been going on with the bomb building, but once he'd stopped being paid it was build differently in a different place without his ability to tell the FBI what was happening. Many CTs have tried to place the taped conversation prior to the bombing and to use the poor english structures to claim that Emad himself was the bomb builder and did it under FBI supervision.
 
No, it's fine by me as it stands!! I come here to learn. If there was no possibility of me being ignorant about something there would be no point in my being here.

Perhaps you'd like to try and answer the question yourself after you've done the honours. It might be a good stretch for your mind. Here's what is says about gravel in my big dictionary to help you on your way:

"a mass of small round mixed stones or rock fragments".

Perhaps American gravel is different.


"Concrete" without large aggregates is called grout, or sometimes mortar.


http://pubs.usgs.gov/of/2005/1165/508OF05-1165.html
Concrete

Concrete is composed of aggregate, sand, and Portland cement (Chandra and Berntsson, 2003). The aggregate material in WTC concrete sample appears to be expanded shale. The sand is primarily quartz, but can contain feldspar, iron and titanium oxides, micas, and other rock-forming minerals. Portlandite (Ca(OH)2) and magnesium hydroxide are also present in minor to trace amounts. Portland cement hydrates to form a large variety of Ca-rich phases including calcium silicate hydrate, calcium aluminum hydrate, calcium aluminum iron hydrate, and Portlandite (Ca(OH)2) (Chandra and Berntsson, 2003). Portlandite is indistinguishable from lime (CaO) using qualitative EDS. Minor gypsum is added to control the set of the concrete.
Particles identifiable as concrete in WTC dust are those constituting the Portland cement component. Portland cement particles will usually have a high Ca peak accompanied by Si and/or Al, Mg, Fe. Most particles of Portland cement will be composed of several Ca-rich phases. These phases are generally extremely fine grained and often occur without distinct grain boundaries. These phases can usually be differentiated using backscattered electron imaging combined with EDS analysis.
A large proportion of the quartz in WTC dust is likely from disaggregated concrete, but has been grouped below with mineral material. Calcite (CaCO3) and dolomite (CaMg(CO3)2) are also components of concrete, but as with quartz, have been grouped with mineral material because they can be present from a variety of sources.
 
BTW, I usually follow up links provided by scientifically -minded "debunkers", such as the one Mackie (?) gave me about dust analysis earlier in this thread, and they frequently do not say what the debunkers claim they say. I am always amazed by this but it happens very often!

If you are suggesting that I attempted to mislead you about the content or relevance of the Lioy et al. paper, you are (again) confused. Feel free to ask questions about the paper or our conclusions therefrom if, as it appears, you need to.
 
Evidence explained equally well by both theories:
  1. Witnesses heard sounds which some described as explosions.
  2. Expulsions of dust and heavy debris.
  3. Bones on the roof.
  4. Collapse duration.
  5. Fairly symmetrical complete collapse.

Explusions of dust and heavy debris. How is this consistent with impact/gravitational collapse? Why is a significant portion of the mass being pulverized and ejected outwards? That sounds like it should go into to CD theory.

Bones on the roof How is this consistent with a gravitational collapse? How were the bodies pulverized and then ejected laterally across the street? "Many are in the size range of one-sixteenth of an inch," said Ellen Borakove, spokeswoman for the city medical examiner's office. What was doing the crushing, intact concrete floors or Ryan Mackey's "cushion of debris"?

Collapse duration The "official" explanation for what happened after initiation is Bazant's crush-down/crush-up hypothesis. Crushing and collapsing are two distinct types of physical phenomena. Is the "collapse duration" consistent with the upper block crushing the lower block?

Fairly symmetrical complete collapse. Can you provide any examples of a complete progressive collapse of steel-frame high-rise? If not, was is that assumption based on?

Evidence not explained well by either theory:

  1. High temperatures in the piles.
  2. Intergranular melting.
  3. So called "Squibs". (Expulsions are too slow to be causes by high explosives. No detailed "over-pressure" explanation has been provided.

This evidence might not be explained by a standard demolition. It is easily explained if one considers the collapse of WTC1 and 2 to be non-standard.

Evidence supporting or better explained by the Impact/fire/gravitational collapse theory:
  1. Damaged by airplane impact. (doesn't apply to WTC7)
  2. The buildings had horrendous fires.
  3. No explosions are heard on the video tapes of the collapses with sound.
  4. The collapses initiated in the damaged areas.
  5. No evidence of common controlled demolition devices identified by anyone.
  6. Seismic measurements did not show an explosions.

The plane impact is not a feature of the collapse. Horrendous fires have never caused an event even remotely similar to the destruction of WTC1 and 2. The "collapse" starting in the damage areas can be explained by the demolition charges beginning in those areas.

Primary analyses supporting the Impact/fire/gravitational collapse theory:
  1. NIST Fire model. (Supports heating on the structural steel.)
  2. NIST Collapse model. (Tweaked input parameters, which may not have been necessary if they had the correct load distribution.)
  3. Complete NIST theory. (Flawed by relying on inadequate analysis of fire-proofing damage.)
  4. Bazant Simple analyses. (To simple to be a convincing proof, but subsequent analyses show that the conclusion was correct.)

NIST stops their analysis at the point of collapse initiation. So how does that support the gravitational collapse theory? What analysis showed Bazant's conclusion was correct? Can I see an experiment that proves the validity of the crush-down/crush-up hypothesis?
 
Bones on the roof How is this consistent with a gravitational collapse? How were the bodies pulverized and then ejected laterally across the street? "Many are in the size range of one-sixteenth of an inch," said Ellen Borakove, spokeswoman for the city medical examiner's office. What was doing the crushing, intact concrete floors or Ryan Mackey's "cushion of debris"?

Who said they were all from the collapse? They also could have been from the plane impact.

For example, bones were found on the roof of the Deutsche Bank building, which was right below the impact site of WTC2.
 
I'm happy, but you have not answered the question. What force would be required to stop the upper part before the elastic limit was reached?

But I did. F = 1.6 GN. It would compress the lower structure 0.8 m elastically. The static force of the upper part is only 0.33 GN, so after decompression, it will compress the spring or lower structure only say 0.165 m. As before initiation.

It is plenty of strain energy that your big spring (lower structure) can absorb, but the force is big so it will punch a hole in the floors, etc.

Actually the upper part can never apply a force F 5 times its own weight given the conditions. Fire/heat will just produce a very slow downward displacement not seen on any video, where the upper part disintegrates before that.
 
But I did. F = 1.6 GN. It would compress the lower structure 0.8 m elastically. The static force of the upper part is only 0.33 GN, so after decompression, it will compress the spring or lower structure only say 0.165 m. As before initiation.

It is plenty of strain energy that your big spring (lower structure) can absorb, but the force is big so it will punch a hole in the floors, etc.

Actually the upper part can never apply a force F 5 times its own weight given the conditions. Fire/heat will just produce a very slow downward displacement not seen on any video, where the upper part disintegrates before that.

Do buildings float? It's really a simple question. Why will you not answer?

Ok here's another one

If you took a ship and dropped it from 1000' into the ground what would happen?
 
But I did. F = 1.6 GN. It would compress the lower structure 0.8 m elastically. The static force of the upper part is only 0.33 GN, so after decompression, it will compress the spring or lower structure only say 0.165 m. As before initiation.

It is plenty of strain energy that your big spring (lower structure) can absorb, but the force is big so it will punch a hole in the floors, etc.

Actually the upper part can never apply a force F 5 times its own weight given the conditions. Fire/heat will just produce a very slow downward displacement not seen on any video, where the upper part disintegrates before that.

You are calculating the force required to compress the lower spring to the elastic limit based on the spring constant, which is useful to compare, but not what I am asking for.

How much force would be required to decelerate the top part to a stop within 0.8m? The spring constant has no bearing on this. It's simply F=ma. Remember that the force increases linearly (from zero) with the deflection of the spring. It's the force at the elastic limit that I am interested in.
 
An explanation, but not as we know it.

#820:

If you are suggesting that I attempted to mislead you about the content or relevance of the Lioy et al. paper, you are (again) confused. Feel free to ask questions about the paper or our conclusions therefrom if, as it appears, you need to.


I'm not suggesting that you were trying to mislead me but you do misrepresent the contents of the paper. I do not speculate on possible reasons for this, though your loose understanding of the word "explanation" is, once again, highlighted.


On page 21, comment 820, in response to my comment:

Perhaps, then, you'd like to share some pre-911 articles describing how collapsing high rise buildings routinely transform their contents into mid-air mushrooming clouds of microscopic dust and how building fires can be expected to cause the intergranular melting such as that observed in WTC steel, which The New York Times described as the "deepest mystery" to emerge from the FEMA report.


you wrote:
Your characterization of the dust is wrong. See Lioy et al. for an explanation of its contents, which are entirely ordinary in a structure collapse.

The article ( Lioy et al.) does not give an explanation of the dust contents, as you claim, but a description (This "explanation" word seems a bit sticky for you! See my post #983, page 25). The paper does not investigate or explain the process which formed the dust though mentions, in passing "the previously unseen degree of pulverization of the building materials." It simply accepts the collapse theories offered by other studies and examines the dust for its possible health ramifications.

It doesn’t define the average particle size or the proportion of dust that derives from concrete and does not address the possibility of explosive residues. It is questionable how representative the small number of samples are, anyway, due to their locations which bias the samples towards lightweight contents.

I requested "some pre-911 articles describing how collapsing high rise buildings routinely transform their contents into mid-air mushrooming clouds of microscopic dust". I accept that my "microscopic" characterisation was wrong but that isn't relevant to my request for articles describing how collapsing buildings routinely pulverize their contents. The Lioy et al. paper isn't such an article though you do seem to represent it as such. It is an artcle about the dust but not about how it was created.
 
#820:




I'm not suggesting that you were trying to mislead me but you do misrepresent the contents of the paper. I do not speculate on possible reasons for this, though your loose understanding of the word "explanation" is, once again, highlighted.


On page 21, comment 820, in response to my comment:

[/COLOR]

you wrote:


The article ( Lioy et al.) does not give an explanation of the dust contents, as you claim, but a description (This "explanation" word seems a bit sticky for you! See my post #983, page 25). The paper does not investigate or explain the process which formed the dust though mentions, in passing "the previously unseen degree of pulverization of the building materials." It simply accepts the collapse theories offered by other studies and examines the dust for its possible health ramifications.

It doesn’t define the average particle size or the proportion of dust that derives from concrete and does not address the possibility of explosive residues. It is questionable how representative the small number of samples are, anyway, due to their locations which bias the samples towards lightweight contents.

I requested "some pre-911 articles describing how collapsing high rise buildings routinely transform their contents into mid-air mushrooming clouds of microscopic dust". I accept that my "microscopic" characterisation was wrong but that isn't relevant to my request for articles describing how collapsing buildings routinely pulverize their contents. The Lioy et al. paper isn't such an article though you do seem to represent it as such. It is an artcle about the dust but not about how it was created.

You must have an example of a CD pulverizing concrete then. Please show the video you must have of a CD that looked just like the towers.

Unless you want to claim that this was the first time it happened with CD like this.
 
Explusions of dust and heavy debris. How is this consistent with impact/gravitational collapse? Why is a significant portion of the mass being pulverized and ejected outwards? That sounds like it should go into to CD theory.

Bones on the roof How is this consistent with a gravitational collapse? How were the bodies pulverized and then ejected laterally across the street? "Many are in the size range of one-sixteenth of an inch," said Ellen Borakove, spokeswoman for the city medical examiner's office. What was doing the crushing, intact concrete floors or Ryan Mackey's "cushion of debris"?

Engineers at STJ911 have calculated the pressures caused by impacts during the collapse. Whether it is called a "cushion" or whatever, 70-80% (estimate agreed on by Greg Jenkins, Tony Szamboti at STJ911 forum) of the debris ended up in the footprint. This falling mass impacted floor after floor at speeds approaching 90 mph. The pressure of the impacts approached 100,000 psi. Repeated impacts at only 10,000 psi would grind a human body to dust. The air pressure was such that the air being expelled approached a velocity of 200 m/s. I have calculated myself that expulsions from floors in the 50s range could have easily reached the top of the DB building. This is unpublished but reliable as far as I am concerned.

Collapse duration The "official" explanation for what happened after initiation is Bazant's crush-down/crush-up hypothesis. Crushing and collapsing are two distinct types of physical phenomena. Is the "collapse duration" consistent with the upper block crushing the lower block?

See my paper on the collapse times (the second paper linked in my previous post). Whether Bazant's model is completely realistic or not has no bearing on this.

Fairly symmetrical complete collapse. Can you provide any examples of a complete progressive collapse of steel-frame high-rise? If not, was is that assumption based on?

There are no examples. Can you provide examples of high rise tube constructions that have been impacted by airplanes and survived? It's not an assumption. A number of unpublished analyses have been done that show fairly convincingly that:

1. If the collapse initiated, that it would continue. See the last paper linked in my previous post.
2. The top would not fall or slide off. (Mackey's paper)

This evidence might not be explained by a standard demolition. It is easily explained if one considers the collapse of WTC1 and 2 to be non-standard.

I have not seen any explanations yet that are convincing. That doesn't mean they don't exist.

The plane impact is not a feature of the collapse. Horrendous fires have never caused an event even remotely similar to the destruction of WTC1 and 2. The "collapse" starting in the damage areas can be explained by the demolition charges beginning in those areas.

The impact damage is evidence that the structure was weakened. Airplane impacts of this magnitude in similar buildings and the resulting fires have never not resulted in complete collapses.

NIST stops their analysis at the point of collapse initiation. So how does that support the gravitational collapse theory? What analysis showed Bazant's conclusion was correct? Can I see an experiment that proves the validity of the crush-down/crush-up hypothesis?

See the last article I linked above. It shows rather convincingly the Ross was wrong and that when Bazant's simple model is made more realistic, that the conclusion was correct. It is unnecessary to prove crush-down/crush-up. I'm not saying it is entirely realistic, in fact David Benson, one of the authors of that paper acknowledges that it is not 100% realistic. It's important to remember that momentum transfer, the governing phenomena in the collapse, is not that dependent on whether the falling mass is intact or not.
 
Please explain how you reached this conclusion from the extract you quoted with it.

Thanks

Because you said it looked like a CD because the concrete was pulverized. Therefore I ask you how does CD's pulverize concrete.
 
Stundie award update

Many thanks to Grizzly Bear, Dave Rogers and A W Smith for their attempts to clear up the aggregate/gravel confusion generated by my possibly award-winning question. Grizzly Bear hits the nail on the head. My error was failing to realise that the aggregate sold by builders merchants containing sharp sand and gravel is just one example of aggregate which is a broader term than I thought.

Perhaps the "gravel" in the debris pile is what I’d call hardcore and not gravel at all as i understand it ("a mass of small round mixed stones or rock fragments").

What is the origin of the word "Stundie"? Will my medal be sent to me or do I have to pick it up myself?

Actually I'm not sure my question qualifies for the Stundies as it resulted from simple lack of knowledge rather than a total lack of rational thought.

Amen to gravel.
 
Many thanks to Grizzly Bear, Dave Rogers and A W Smith for their attempts to clear up the aggregate/gravel confusion generated by my possibly award-winning question. Grizzly Bear hits the nail on the head. My error was failing to realise that the aggregate sold by builders merchants containing sharp sand and gravel is just one example of aggregate which is a broader term than I thought.

Perhaps the "gravel" in the debris pile is what I’d call hardcore and not gravel at all as i understand it ("a mass of small round mixed stones or rock fragments").

What is the origin of the word "Stundie"? Will my medal be sent to me or do I have to pick it up myself?

Actually I'm not sure my question qualifies for the Stundies as it resulted from simple lack of knowledge rather than a total lack of rational thought.

Amen to gravel.

Is water wet? fire hot? gravel rocks?
 
Actually I'm not sure my question qualifies for the Stundies as it resulted from simple lack of knowledge rather than a total lack of rational thought.

Given that it was a simple lack of knowledge, I think it doesn't. Thanks to A. W. Smith for answering the question you meant to ask; I honestly couldn't see what you were getting at.

Dave
 
I requested "some pre-911 articles describing how collapsing high rise buildings routinely transform their contents into mid-air mushrooming clouds of microscopic dust". I accept that my "microscopic" characterisation was wrong but that isn't relevant to my request for articles describing how collapsing buildings routinely pulverize their contents.
Then you're back in your "comfort zone", requesting evidence and comparables where none can possibly exist in order to bolster your delusional state.
No building of even remotely comparable size has ever collapsed from the top down in the manner of WTC1 + 2. Even major CDs have the contents stripped out prior to demolition.


The Lioy et al. paper isn't such an article though you do seem to represent it as such. It is an artcle about the dust but not about how it was created.

No it isn't. It's an article about some of the dust. Specifically lightweight, drifting dust sampled from under cover (significant fact) and at a distance (significant fact) from GZ. It was sampled in this way quite deliberately and is not at all representative of the general state of the non-metallic debris at GZ.
 
You are calculating the force required to compress the lower spring to the elastic limit based on the spring constant, which is useful to compare, but not what I am asking for.

How much force would be required to decelerate the top part to a stop within 0.8m? The spring constant has no bearing on this. It's simply F=ma. Remember that the force increases linearly (from zero) with the deflection of the spring. It's the force at the elastic limit that I am interested in.

?? The spring just acts as a damper and its damping force F increases with elastic compression. This damping force is evidently transmitted to the top part that decelarates assuming that the lower spring damping force F will not destroy the upper part in the process. The spring is not deflected - just compressed in this thought example.
I suggest of course that the upper part is the first to be destroyed by the damping force at initiation as it is not very strong and damaged by fire.
But in my example the damping force is just friction between damaged parts.

Strangely neither NIST nor Bazant considers damping or friction to occur after initiation.

When the top part is arrested you need a big crane to lift it back in original position 3.7 m higher up. For that you need 40 kgs of diesel oil. All explained in my articles.
 
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Because you said it looked like a CD because the concrete was pulverized. Therefore I ask you how does CD's pulverize concrete.

Please show where I have said "it looked like a CD". I have never said it, as far as I remember.

My problem is in not understanding how gravity simultaneously pulverized material by crushing it between floors and then ejected this material in one action.

Many people who will never be considered for the Stundies have commented on the unusually comprehensive pulverization of the buildings non-metallic contents and components.

GregoryUrich, above, states that "70-80% (estimate agreed on by Greg Jenkins, Tony Szamboti at STJ911 forum) of the debris ended up in the footprint."

Blanchard claims, citing photographic and video evidence, that 90% (if my memory serves me correctly) of the debris fell outside the buildings' footprints.

Arguments claiming the the CD hypothesis is supported by the fact that the buildings fell into the Towers' footprints are debunked by pointing out that most of it fell outside their footprints.

There are huge contradictions in the "collapse caused the pulverization" theory. Did the mass of the building fall inside or outside the buildings footprints? I don't see a consensus amongst the "experts".

Those who cover these gaping holes in their arguments by demanding evidence of CD are just putting up smokescreens to distract attention from their own weak theories!
 

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