The 9/11 Forum

I'm just presenting general ideas at the beginning as a rough list.

Any details are fine, too. We want to include everything.

We are working towards a clean, no BS list, most important features first, linked and referenced in a comprehensive but easily readable form.

As much simplicity as some people need, but with as much detail and quality as possible.

When anyone wants to present a strong list I could edit the OP and keep it up to date.

Where is the Achimspok list? Maybe we start with that?




I think this may be the best way to argue why speed of collapse is highly suspicious (I'm changing the wording of my last posts).

.........................................

The WTC7 speed of collapse, particularly the first 3 seconds, is too rapid to be the result of natural causes. Why? Comparison with

a) fall times of known demolitions
b) computer simulations of collapsing buildings
c) Fall time estimates applying classical mechanics

all show WTC7, especially during the first 3 seconds of collapse, to provide an unnatural lack of resistance to being destroyed.

............................................

I think the above is technically true. Anyone disagree?

Note to OWE: My guess is that you will point out the einsteen collapse speed estimates pushing the limits of this claim.

I assume that classical mechanics is just a type of tool for for us to understand fall times of buildings. The only way to really test it is to do the experiment and see what happens. The estimate of a fall time of a WTC7 sized building given by Dr G when comparing with known demolitions is much more than some estimates using classical mechanics.

Why do you think that is so?

Which way, observing known demolitions or estimating using simplified classical mechanics, seems more valid to you?

(I would think observing known demos would provide a reality check to fall time estimates derived from classical mechanics.)

Continuing our search for questionable WTC7 collapse features, it's always nice to review the Achimspok videos on the subject.

He has 8 WTC7 clips available at

http://www.youtube.com/view_play_list?p=6364602C500D71BB

(3 videos have the title "North Tower" but they really concern WTC7.)

I'll be examining this info to see if it helps us and how.

Comments to follow.

The 8 videos linked in the last post fall into two groups

1) presentation of questionable collapse features:

NORTH TOWER part2 - Ch22a updt
http://www.youtube.com/watch?v=KELwL9DCqqw&feature=PlayList&p=6364602C500D71BB&index=0

NORTH TOWER part2 - Ch22b
http://www.youtube.com/watch?v=ldO0c2iMmlk&feature=PlayList&p=6364602C500D71BB&index=1

NORTH TOWER part2 - Ch22c
http://www.youtube.com/watch?v=jqkUNzaxiCA&feature=PlayList&p=6364602C500D71BB&index=2


The 3 clips together seem to give a general summary of what he thinks are tha most important suspicious features to note.




2) Analysis and criticism of the NIST interpretation of WTC7

(I'll discuss the "The NIST predecisional WTC7 Report" videos a bit later in the thread)



This seems a good way to present the entire WTC7 subject (as two parts) so that is what I will do too.

The two parts are:

1) Comprehensive list of WTC7 questionable collapse features (most important features first, each containing links and references with the most accurate data)

2) Analysis and criticism of the NIST interpretation of WTC7 and of all other viable alternative theories.

So far in this thread we have been doing only part #1.

..............................................

The Achimspok list of features from the three linked videos above seem to be.........

From Ch 22a
1) Reports on the WTC7 collapse before it actually happened
2) Video of fires showing they are only on specific floors and limited, hardly "raging"
3) Speed of collapse (virtually no resistance)

From Ch 22c
4) Rapid, near simultaneous lateral collapse progression to initiate collapse
4) Smoke suction movement around the east penthouse shows something collapsed inward just before we see penthouse move
5) Speed of penthouse collapse

He also analyzes video of south side to try to verify actual damage from WTC1 debris.

Hi. Sorry, I've been occupied administering bitch-slaps to OCTers.

Major_Tom wrote:Note to OWE: My guess is that you will point out the einsteen collapse speed estimates pushing the limits of this claim.

It's a very simple but informative model, an easy way to get a feel for the dynamics of crush-up. Highly idealized, but can be tweaked and extended up to a point, and well-suited to computation.

I assume that classical mechanics is just a type of tool for for us to understand fall times of buildings.

Mechanics can put a box around at least part of the problem and also provide insight. Unfortunately, there aren't many interesting systems that can be solved analytically. Bearing in mind that most analytical solutions use tricks like series and small angle approximations, etc, it's a wonder they have much validity in the real world, but they do.

Classical mechanics does alright with points or rigid bodies of simple shape, moving through a vacuum under the influence of a conservative potential, and not making contact with anything else. Once bodies start making contact, the situation becomes intractable quickly (see this pendulum app) and gets worse until it gets better, when the law of large numbers starts to kick in. With enough bodies and enough collisions, different properties emerge. Then there's deformation and breakage.

Check out granular material, multi-phase flow, power law, rheopecty, and non-newtonian fluids as a sampler. By definition, a statistical approach does not concern itself with the details of the parts. If detail is required, in solutions or formulations, this may not be a good approach. No matter how many parts a Rube Goldberg machine has, it will never be a candidate for statistical methods. This is where simulation, based on mechanics, enters the picture. But, I don't think human beings are as accomplished at simulating specific realities as they think they are.

The only way to really test it is to do the experiment and see what happens.

Yes!

he estimate of a fall time of a WTC7 sized building given by Dr G when comparing with known demolitions is much more than some estimates using classical mechanics.

Why do you think that is so?

That's a really tough question. I don't know. A much larger set of internal degrees of freedom, affecting the energy distribution over time, but that's pretty vague.

Which way, observing known demolitions or estimating using simplified classical mechanics, seems more valid to you?

They (can and should) complement each other. Observing known demolitions is good, but not sufficient - the properties of the structure must also be known in some fashion. There have been videos lately of complete crush up/downs, arrested collapse and even rolling. The buildings are different, but in what way? How are the differences (materials, layout, etc) reduced to a few representative parameters (height, density, etc) that give generally applicable results? Is this always possible? Don't know.

(I would think observing known demos would provide a reality check to fall time estimates derived from classical mechanics.)

Yes, if the mechanics were sophisticated enough to make predictions. Right now, I think it's probably way more than reality checks, it's just plain reality, like Newton experimenting with collisions to find restitution. Demos should be used to discover and calibrate the parametric input to computations. Perhaps steel office furniture greatly accelerates collapse, versus particle board, versus none at all as in a demo. Or maybe it's the reverse.

Perhaps steel office furniture greatly accelerates collapse, versus particle board, versus none at all as in a demo. Or maybe it's the reverse.

steel furniture or particle board would slow the collapse, not accelerate it, wouldn't it? rigidity is the issue, according to demolitionists. that's why part of prepping a building is knocking out some vertical walls. they are like weak columns.
steel desks are more massive than MDF, but, also stronger, and more malleable.
more strength to crush equals longer time for crushing, and steel's a fine cushion, while mdf is more brittle and easy to break, and so not so good.

anyway, it's more inertia and work to be done in either case, and so it takes more time, not less, for a full building to crush itself than it takes an empty one to fall.

newton wrote:steel furniture or particle board would slow the collapse, not accelerate it, wouldn't it?

Intuitively, that's what I'd think on a very general level. But even as I was writing it, I realized there are all sorts of factors to consider. Office contents add volume to the interior that must be crushed and/or displaced. A hypothetical rubble front can't fall as far before encountering resistance; less PE lost before reaction to resistive force is applied to the floor diaphragm below.

If the contents are easily crushed at first and become increasingly incompressible as the volume diminishes, the structure below is able to exert a retarding force over a longer distance/time and is able to decelerate the rubble with a lower peak force. A cushion. Steel furniture is stronger and more rigid, so will resist crushing and transmit a higher peak force. If the impulse is still sufficent to fail the diaphragm, lateral support of vertical members can consequently be reduced. If there's sufficient energy to fail the story with either type of contents, the steel may cause the lower crush front to propagate downwards quicker but have the roofline descend slower, all because of compaction ratio. Demolition companies naturally clear everything out and would have to even if having the stuff there made the demolition task easier, so here's a case where other considerations dictate the influence not even be considered.

BTW, do check out the pendulum link above. Start the app and watch it for about 30 seconds, see that the motion is regular like a newton's cradle, then leave it alone for about 20 minutes and come back. Now the motion is chaotic and aperiodic; this is a floating-point simulation using classical mechanics in a piecewise fashion, punctuated by collisions, with ideal bobs and conservative force. If such a simple system can get so crazy....

I don't want to stray too far from the thread's objective, so I'll find another place to shoehorn these other comments. On the matter of whether WTC7 fell too quickly, NIST's simulation seems to indicate it did. Now, I don't put much stock in their sim when it comes to the global collapse - WTC7 did not crinkle up like a beer can without losing significant elevation. Their simulation purports to show the progression from the identified initial cause, but it doesn't match observables. Either the initial cause is incorrect, or the solution obtained is incorrect.

LOVE that newton's cradle app.
shows perfectly how my mind works.

bing, bang, bing, boink, donk......

but, seriously, that is how my mind works. the momentum transfers are exactly what i would expect with each collision. everybody eats from the same force pie. when someone takes a big bite, the others go hungry.

nice.

MT:(I would think observing known demos would provide a reality check to fall time estimates derived from classical mechanics.)

OWE replies: Yes, if the mechanics were sophisticated enough to make predictions. Right now, I think it's probably way more than reality checks, it's just plain reality, like Newton experimenting with collisions to find restitution. Demos should be used to discover and calibrate the parametric input to computations.

I agree, it is the strongest connection to reality we have. Known demos, not classical mechanical simplified models, give us the strongest reality checks.

People should tweak the classical mechanics to match what we see in demos (the real thing). Then we know our mechanical model is more real.

Some people give these 1-D equations a life of their own, like Frankenstein.


So the big question is do you think this is technically true?

.........................................

The WTC7 speed of collapse, particularly the first 3 seconds, is too rapid to be the result of natural causes. Why? Comparison with

a) fall times of known demolitions
b) computer simulations of collapsing buildings
c) Fall time estimates applying classical mechanics

all show WTC7, especially during the first 3 seconds of collapse, to provide an unnatural lack of resistance to being destroyed.

............................................

This will be high on the WTC7 list (very high) so I wanted to run it by the skeptics to get your opinions.

Of the three comparison methods:

a) fall times of known demolitions
b) computer simulations of collapsing buildings
c) Fall time estimates applying classical mechanics

"a" is the most important comparison, "b" next and "c" last.

Watching known demos can give us our best understanding of realistic limits and expectations. (A Dr G notes, WTC7 falls considerably faster than known demolitions.)

I think computer simulations can open our minds to what is possible also.


1-D classical mechanics estimates are the method most subject to error. (The BZ paper is a great example of claims based on classical mechanics are apparently contradicted by observing known demos.) Their results need to be put into perspective by observing real crush-up, crush-down processes. That is why I write the list in the order I do.

Nobody has a problem with the speed statement?

Problem solved (bottom of the page):
http://the911forum.freeforums.org/the-pub-t82-165.html#p4674

Major_Tom wrote:So the big question is do you think this is technically true?

Yes to what proceeds it, a more qualified answer to what follows.

The WTC7 speed of collapse, particularly the first 3 seconds, is too rapid to be the result of natural causes.

I can't agree because I don't know, but it's not that I strongly disagree. It is very curious. It does seem to be too rapid for a CD, but I have no comparable 'natural' examples from which to work, even other CDs have very limited comparability, so it's all speculation for me. I will speculate more if any (good) ideas come to me. Somehow it came down that fast, that's the reality we have to grapple with, even the CD examples don't answer the question. Not at this stage, anyway.

This will be high on the WTC7 list (very high)...

Yes, it should be high, there I agree wholeheartedly.

I can't agree because I don't know, but it's not that I strongly disagree. It is very curious.

I think we agree on the general meaning. I am writing it in a provocative way. No doubt it merits further investigation and no annointed "expert" is even in the "ballpark". Not even close.

Demos are our only fragile contact with basic physical reality. Demos give me an upper limit on what normally can happens with massive structural manipulation.

When you are far above demo speed...that is worth a freakin' investigation.

I'm thinking....if it was put out as a challenge, could anyone suggest physical systems that attain structural failure at this speed? Doubt it. And the nature of such physical systems would be quite telling.



Anyway, on the list, the visible fires were very limited.

Useful to compare it to the Chinese TV Hotel fire.





and the next day,


Link to info at the CIT forum

http://z3.invisionfree.com/CIT/index.php?showtopic=514

OWE wrote:

Mechanics can put a box around at least part of the problem and also provide insight. Unfortunately, there aren't many interesting systems that can be solved analytically. Bearing in mind that most analytical solutions use tricks like series and small angle approximations, etc, it's a wonder they have much validity in the real world, but they do.

Classical mechanics does alright with points or rigid bodies of simple shape, moving through a vacuum under the influence of a conservative potential, and not making contact with anything else. Once bodies start making contact, the situation becomes intractable quickly (see this pendulum app) and gets worse until it gets better, when the law of large numbers starts to kick in. With enough bodies and enough collisions, different properties emerge. Then there's deformation and breakage.

Check out granular material, multi-phase flow, power law, rheopecty, and non-newtonian fluids as a sampler.

Totally agree. So the basic application of 1-D mechanics equations for crush-up, crush-down should somewhat match the motion of known demos if we are to take them seriously.

I'll tell you what my gut feeling is about the discrepancy between 1-D results and real buildings.


1) There is a sizable energy sink within the crush zone of real demos that is not dealt with correctly in the simple 1-D models.

2) The nature of the stuff in "zone B", the mechanism of impacts and crushing (and recrushing and recrushing) is so overly simplified that the 1-D model becomes somewhat useless in predicting movement. People don't really understand the physical nature of zone B.

3) The actual impacts between "zones A and C" via "zone B" is more cushioned due to flow and crushing than people realize. You cannot treat zone B totally as a compact solid. Zone B cannot be instantaneously converted to a solid mass now moving as one with the upper block.



Your "granular material" link is a great example
http://en.wikipedia.org/wiki/Granular_material

Notice you can apply this to things as large as ice flows involving icebergs.

From the link:

In some sense, granular materials do not constitute a single phase of matter but have flow characteristics that roughly resemble those of ordinary Newtonian fluids. However, granular materials dissipate energy quickly, so techniques of statistical mechanics that assume conservation of energy are of limited use.

So why do the estimates by Dr G of the WTC7 fall based on comparison of known demos differ from estimates using basic principles of mechanics? Because there is a type of energy sink people are not accounting for?

Or why do known demos fall at the speeds they do?


From another angle, we can see that known crush-up, crush-down demos consume both the upper and lower blocks in the process of crushing. Say the ratio of destruction of upper to lower is A:B. A and B can be time dependent.

Q: What happens when the solid portion of zone A is totally crushed?

For example, if A:B is 1:1 and you start the demo near the center of the building, you can expect total complementary destruction. But what if initiation is much higher in the building with a 1:1 destruction ratio?

You will "use up" the upper block before the lower block is destroyed. This placement of the initiation near the center of the building is actually what we see in the Balzac demo. I think they chose the center because they know what they are doing and they wouldn't trust the conclusions of BZ in practice. What demo company would depend on the claim of inevitable total destruction from the removal of over 50% of columns on only one floor? They would be insane to believe so considering that demos occasionally do fail under more extreme column removal.


Upper blocks can be "used up" midway into the collapse. What happens then? What is doing the crushing? The nature of the process must change.

This is the case of WTC1. The upper block was quickly "used up" yet the mechanics of BLGB does not recognize this reality. They imagine some "eternally preserved" Zone A, an idea that falls to pieces when we look at actual demos. This way, they never have to deal with the exhaustion of zone A which clearly happened for WTC1 and is something real demo companies must consider.

Major_Tom wrote:I'll tell you what my gut feeling is about the discrepancy between 1-D results and real buildings.

Yes to all three items. But, but, but... I think there's something to be said for the destructive power of a moving fluid, too. Also, at the boundary layer, yet more (different) rules apply. The Blackhawk landslide:

http://www.gps.caltech.edu/classes/ge111/1999/

I marvel at how far this rubble traveled horizontally. Air hockey with rocks and dirt on the desert floor.

From a non-fluid perspective, the crush-up sim Dr. G linked to showed strain distributed up the structure. If the energy to strain and deform many stories of a steel skeleton is coming from loss of elevation, it's going to be a slower descent than one in which the dissipation is localized to the crush front. The sim didn't have an internal collapse, though, something to be mindful of in WTC7's case.

There was a video posted a couple of months ago, WTC1 from the south, seemed like a helicopter. I'd never seen it before, need to look at it again. I swear the upper block slowed wayyy the hell down at about the same time the expulsions were tearing ahead down below. Quite a bit of the mass took a long time to hit the deck, in any case. This goes back to the question of the definition of collapse time. Part of it really fast, part of it really slow, most of it in between. The 1D model is definite and gives a singular result.

This by no means an intelligent response to your post, today is not one of those intelligent days.

There are 4 more elements I'll include on this list. I don't use eyewitness accounts much but there are a few concerning WTC7 which are pretty powerful

1) Berry Jennings testimony of explosions inside WTC7
2) Kurt Sonnenfeld info about the security vault used by federal agencies below WTC6 being empty http://www.voltairenet.org/article160636.html

These witness statements are not made just in the chaos of the moment and seem to belong on the list.

I'll also include

3) multiple accounts of evacuation the area around WTC7 in preparation for it's collapse and
4) Increased smoke activity at the base of WTC7 just before collapse that Achimspok documents pretty well.

One more major point will be how the explanation given by the NIST doesn't come close to explaining the collapse. This point is clearly very important and will require a well documented list of it's own explaining problems with the NIST WTC7 report which the good members of this forum have already uncovered.


Any other things that someone think should be added? Anyone object to a particular entry?

Within the next few posts I'll assemble the list using the info within this thread.

The list.......

Questionable WTC7 features and events in order of importance:

1) Symmetry of collapse: Rapid, near simultaneous lateral collapse progression to initiate collapse

2) Speed of collapse:

The WTC7 speed of collapse, particularly the first 3 seconds, is too rapid to be the result of natural causes. Why? Comparison with

a) fall times of known demolitions
b) computer simulations of collapsing buildings
c) Fall time estimates applying classical mechanics

all show WTC7, especially during the first 3 seconds of collapse, to provide an unnatural lack of resistance to being destroyed.

3) Fold-in nature of collapse and compact, inward folded rubble pile.

4) Jet flames seen just before collapse from near collapse initiation floors

5) Fires much, much smaller than other highrise fires which did not lead to collapse.

6) Early collapse of east penthouse, speed of penthouse collapse as it can be seen through the vertical shockwave progression and early smoke suction from behind the east penthouse.

7) Horizontal rocking of building just before collapse

8 ) Reports on the WTC7 collapse before it actually happened

9) Multiple accounts of evacuation the area around WTC7 in preparation for it's collapse

10) Berry Jennings testimony of explosions inside WTC7
>>Good link to interviews, transcripts given on LTF forum http://s1.zetaboards.com/LooseChangeForums/single/?p=108750&t=451652

11) Kurt Sonnenfeld info about the security vault used by federal agencies below WTC6 being empty
>>About Kurt Sonnenfeldhttp://www.voltairenet.org/article160636.html

This is a rough sketch for the list. I am probably missing a few things.

Each item on the list needs to be backed up with links to good data and info.