WTC 1 & 2. What happened after collapse initiation?

[tanabear]

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 This is unpublished but reliable as far as I am concerned.

But was this falling mass intact or pulverized? Look at the mass falling outside the perimeter of the tower, if there was another structure directly beneath it, would we expect this structure to be destroyed the same way as WTC1 and 2? And when you say falling mass, point to it in this picture:

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 A number of unpublished analyses have been done that show fairly convincingly that: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)

There have been many buildings more severely damaged in times of war and none of them collapsed the way WTC1 and 2 did. The fact that an event is in some ways unique does not imply it is more severe. "The impact did nothing to this building." Abolhassan Astaneh-Asl.

Also, how do you know that collapse would initiate? Bazant and Zhou wrote in the paper, Why Did the World Trade Center Collapse?—Simple Analysis

"The downward displacement from the initial equilibrium position to the point of maximum deflection of the lower part (considered to behave elastically) is h+(P/C) where P=maximum force applied by the upper part on the lower part and h=height of critical floor columns (=height of the initial fall of the upper part) ~=3.7 m....the upper part may be assumed to move through distance h almost in a free fall."

Bazant and Verdure state in their March 2007 paper, Mechanics of Progressive Collapse: Learning from WorldTrade Center and Building Demolitions,

"The subsequent progressive collapse was not simulated at NIST because its inevitability, once triggered by impact after column buckling, had already been proven by Bažant and Zhou’s (2002a) comparison of kinetic energy to energy absorption capability."

So was this 3.7 meter fall of the upper block onto the lower block something that Bazant/Greening/Zhou used in their model because it was actually observed or is it merely a hypothetical assumption they made up? If it was something that was actually observed, show me when it happened.

Also in the documentary, Building on Ground Zero Shyam Sunder states, "Suddenly the columns snapped, and, as a result, the entire top of the building came down, pretty much in freefall, because kinetic energy that was unleashed was just huge." In the documentary they show computer animation of this happening. Why don't they provide video/photographic evidence?

Regarding the statement, "The top would not fall or slide off." I don't see the upper block after a certain number of seconds. Observation takes precedence over words on paper.

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.

It is unnecessary to prove the crush-down/crush-up hypothesis?????? When did it no longer become necessary for scientists to prove their theories? Especially when this hypothesis is the basis for the War on Terror, which has led to the death of thousands. Once again, is the falling mass intact or not? Someone might believe it doesn't matter, but I'm asking what actually happened. If physics can't tell us if the upper block would remain intact or not, then it can't tell us much of anything else about the collapse.

 

[Dave Rogers]

Look at the mass falling outside the perimeter of the tower, if there was another structure directly beneath it, would we expect this structure to be destroyed the same way as WTC1 and 2?

http://www.internationalskeptics.com/forums/imagehosting/thum_2118648b4994f17f6a.jpg

Like, for example, WTC3?

When did it no longer become necessary for scientists to prove their theories? Especially when this hypothesis is the basis for the War on Terror, which has led to the death of thousands.

You're claiming that crush-down/crush-up is the basis for the War on Terror? Seriously? Are you really claiming that the single, sole piece of evidence for al-Qaeda's responsibility for 9-11 is Bazant's conclusion that the lower block in a top-down collapse will be preferentially destroyed over the upper block?

Incredible.

Dave

 

[R.Mackey]

R.Mackey has authoritatively assured us, anyway, that talking about a "lightweight bias" is a certain sign of ignorance and typical denialism, probably of several unpleasant varieties. Giant lizards may also be lurking.

Acceptalists aren't supposed to have such thoughts.

I don't know what an "Acceptalist" is, but you should at least try to understand your mistake. You attempted to throw out Dr. Lioy's results, despite being basically a complete novice to, apparently, any field of science, with the following reasoning:

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.

You can't do that. The "bias" you're talking about is completely made up. You invented an excuse to deny existing data. That is denialism in action.

As I explained to you, your excuse is nonsensical. The dust is of such a size that it is not rapidly selected for density. Again, see Stokes' Theorem for a mathematical proof thereof.

Furthermore, had you bothered to read Dr. Lioy's paper, you would see that they deliberately sampled at three locations of increasing distance from Ground Zero specifically to estimate whether the plume varied with distance. As you can see in the results for yourself, while there is some small variation between samples which is to be expected, the overall character remains the same. So there is not only theoretical evidence, but also physical evidence that your excuse is completely wrong.

That's denialism, and you are practicing it.

If you expect me to pay you any attention hereafter, I suggest you start making sense.

 

[Dave Rogers]

911 has allowed scientist-activists to abandon principles of uncertainty for 100% conviction that they are right, despite offering only hypotheses and untested theories as "proof" of their rectitude. Investigations now work backwards towards their single, foregone conclusions, using malleable virtual reality to get them there.

That's one of the best descriptions of Steven Jones I've seen.

Dave

 

[GlennB]

#820:

It is questionable how representative the small number of samples are, anyway, due to their locations which bias the samples towards lightweight contents.

JihadJane - are you under the impression that the Lioy paper was attempting to study the average composition of all non-metallic debris from the WTC complex? This is the only explanation I can think of to explain your use of the word "bias" here. Perhaps you could clarify?

 

[phunk]

OT but actually all buildings on land float ... on the ground. Without ground and force applied by the ground to keep the building in place, they would sink to the centre of the earth. Luckily the ground is quite solid in most cases to maintain equilibrium but sometimes not, e.g. the Tower of Pisa.

There must be a language barrier issue here. The word float does not apply in any way to buildings on solid ground. Floating requires fluid displacement and buoyancy. Sitting on a solid surface is not floating.

 

[Heiwa]

There must be a language barrier issue here. The word float does not apply in any way to buildings on solid ground. Floating requires fluid displacement and buoyancy. Sitting on a solid surface is not floating.

Solid surface? Have you ever been digging? Planted a tree? Made a hole in the ground? Solid? The top soil is non-solid = fluid.
Maybe there is a rock below the top soil? Is the rock really solid? Maybe, at ambient temperature but maybe once upon a time conditions were different. Heat up the rock ... and it becomes more fluid?
Anyway ... according to US NWO physics and Condoleezza Rice the WTC1 upper block was rock solid after initiation (topic) and that caused the crush down as planned by OBL.
So the mistake seems to have been to build rock solid top blocks of US skyscrapers. Someone slept at the switch, again?

 

[Heiwa]

Your teori give the same result for drops of 3,7m and 2 miles.

There debunked, Happy?

Not really. The bottom floor of the upper block is the first to be destroyed at contact because it is the weakest sub-part. Drop height does not matter.

Still sea sick?

 

[Toke]

Not really. The bottom floor of the upper block is the first to be destroyed at contact because it is the weakest sub-part. Drop height does not matter.
Still sea sick?

Not sure if I get this right.

If dropped from 2 miles the bottom floor of upper block will be destroyed, and then everything stop due to friction?

Depending on your answer we can work our way down.
a) 1.5 miles
b) 1 mile
c) 0.5 mile
d) 200m
e) 100m
f) 50m
g) 10m
h) 3,7m


No I do not get seasick, is it a big problem for you

 

[tsig]

Not really. The bottom floor of the upper block is the first to be destroyed at contact because it is the weakest sub-part. Drop height does not matter.

Still sea sick?

Back to the two mile drop thing.

 

[X]

Solid surface? Have you ever been digging? Planted a tree? Made a hole in the ground? Solid? The top soil is non-solid = fluid.
Maybe there is a rock below the top soil? Is the rock really solid? Maybe, at ambient temperature but maybe once upon a time conditions were different. Heat up the rock ... and it becomes more fluid?
Anyway ... according to US NWO physics and Condoleezza Rice the WTC1 upper block was rock solid after initiation (topic) and that caused the crush down as planned by OBL.
So the mistake seems to have been to build rock solid top blocks of US skyscrapers. Someone slept at the switch, again?

Fluid: A fluid is defined as a substance that continually deforms (flows) under an applied shear stress regardless of how small the applied stress.


The ground beneath your feet does not qualify as a fluid. Generally speaking, those who design buildings prefer to put the foundations on surfaces that do not move too much.


Oh, and:
"US NWO physics"?
Paranoid much?

 

[phunk]

Solid surface? Have you ever been digging? Planted a tree? Made a hole in the ground? Solid? The top soil is non-solid = fluid.

Words you should go look up in the dictionary:

Solid
Fluid
Float
Displacement
Buoyancy

I would expect a shipbuilder to know these things.

 

[GlennB]

Solid surface? Have you ever been digging? Planted a tree? Made a hole in the ground? Solid? The top soil is non-solid = fluid.

Heiwa - I can also cut a hole in wood, concrete or metal using a drill. Does this mean they too are fluids?

 

[Heiwa]

Fluid: A fluid is defined as a substance that continually deforms (flows) under an applied shear stress regardless of how small the applied stress.


The ground beneath your feet does not qualify as a fluid. Generally speaking, those who design buildings prefer to put the foundations on surfaces that do not move too much.


Oh, and:
"US NWO physics"?
Paranoid much?

Ever heard about a land slide and what happens before it? But it is OT. Subject is what happened after collapse initiation up top. And according common sense and clear thinking the local failures should have been arrested as it has always happened before.
All these new phenomenons of all kinds on 9/11 are strange and the explanations for them even more so.
I like the new WTC7 explanation. Column 79 is heated up and becomes fluid and the whole structure collapses. A very fluid idea, to say the least.

 

[Heiwa]

Heiwa - I can also cut a hole in wood, concrete or metal using a drill.

Clever guy! Imagine that. Cutting a hole.

 

[Heiwa]

Not sure if I get this right.

If dropped from 2 miles the bottom floor of upper block will be destroyed, and then everything stop due to friction?

Depending on your answer we can work our way down.
a) 1.5 miles
b) 1 mile
c) 0.5 mile
d) 200m
e) 100m
f) 50m
g) 10m
h) 3,7m


No I do not get seasick, is it a big problem for you

No, the first thing that will be destroyed is the bottom floor of the upper block. Bazant and NIST suggest otherwise, i.e. that it remains intact all the time after collapse initiation.

The bottom floor of the upper block is according these clowns intact all the time; during crush down all structure below this floor is crushed down and at crush up later all the structure above this floor is crushed up. The only thing that remains after crush down/up is the bottom floor.

It would appear that the intact floor in question was carefully examined in the
rubble to prove this new phenomenom.

I have a feeling that Bazant and NIST are sea sick on solid ground.

 

[JihadJane]

I don't know what an "Acceptalist" is, but you should at least try to understand your mistake. You attempted to throw out Dr. Lioy's results, despite being basically a complete novice to, apparently, any field of science, with the following reasoning:

An Acceptalist is the opposite of a denialist though without the anti-Semitic connotations. As usual your post is peppered with impossible to substantiate, personalised assertions that have more in common with playground bullying than scientific discourse:

"You invented an excuse"

"...had you bothered to read Dr. Lioy's paper..."

You can't do that. The "bias" you're talking about is completely made up. You invented an excuse to deny existing data. That is denialism in action.

As I explained to you, your excuse is nonsensical. The dust is of such a size that it is not rapidly selected for density. Again, see Stokes' Theorem for a mathematical proof thereof.

Are you still trying to claim that Lioy's study of a portion of a wind-driven portion of the dust cloud can be used to prove that the buildings' behaviour was in no way unexpected?

Furthermore, had you bothered to read Dr. Lioy's paper, you would see that they deliberately sampled at three locations of increasing distance from Ground Zero specifically to estimate whether the plume varied with distance.

Only magic science that turns estimates into undeniable evidence.

If you expect me to pay you any attention hereafter, I suggest you start making sense.

Very funny! Do you really beleive that this kind of childish manipulation works? I am indifferent to your attention.

If I want the truth about the implications of the Lioy et al study I wouldn't expect to find it in politicised, propagandistic ourpourings which use science to bludgeon, bully and obfuscate rather than to enlighten and educate.

 

[JihadJane]

Beams and motes

That's one of the best descriptions of Steven Jones I've seen.

Dave

Two sides of the same coin, perhaps.

 

[Hokulele]

If I want the truth about the implications of the Lioy et al study I wouldn't expect to find it in politicised, propagandistic ourpourings which use science to bludgeon, bully and obfuscate rather than to enlighten and educate.

Apparently you prefer to use politicized, propagandistic outpourings that do not make any use of science at all.

 

[JihadJane]

JihadJane - are you under the impression that the Lioy paper was attempting to study the average composition of all non-metallic debris from the WTC complex?

No, that is why I am puzzled that R.Mackey persists in using it to support his universal claims about the Towers disintegration.

This is the only explanation I can think of to explain your use of the word "bias" here. Perhaps you could clarify?

I believe I (and others) may be wrong in believing the samples had a lightweight bias. R.Mackey claims that these samples would be little different to any others in any location, which, as I understand it, is not what you believe.

As I said to R.Mackey, I would really only be convinced by answers from scientists with less emotional and ideological investment in being right than are available on this site.