Has Anyone Seen A Realistice Explanation For Free Fall Of The Towers?

[TjW]

I have to hand it to Chris; sticking with C4 coated rebar (http://algoxy.com/psych/9-11scenario.html) when he can't actually prove that such a material exists.

Here's my theory; they screwed up the order and got chocolate coated rebar instead; the heat of the fire caused melting and shear on the chocolate/concrete line and the towers failed.

No evidence? Hell, I got just as much as Chris has.......

Damn terrorist Oompa-Loompas... It was supposed to be high-temperature chocolate.

 

[tsig]

And a personal attack.

I find this amusing considering the lecture I have been given about how civilised this forum is.

Laughable.

how was this a personal attack??

 

[David Wong]

Any time I get in a debate from now on, my entire technique will consist of quoting the previous post and typing the word "irrelevant" under it.

I like that. Saves a bunch of time.

 

[gumboot]

If you read back through the posts then you will see that it was you that introduced the tree analogy, NOT ME. I agreed that it was a good analogy to explain to a layman about how the core and trusses worked but put my own limitations on the extent of that analogy. Someone more cynical than me would surmise that you had an agenda bringing trees into it because you probably guessed I knew nothing about this Judy Wood character who it appears has already been the subject of derision on here.

Actually, I believe I brought up the trees. You made a comment that you would expect the top of the building to topple over, rather than collapse down through the rest of the building. Judy Wood made the same argument, using trees as an anology. Hence why I brought it up.

I disagree it is a goof way to explain to a layman about the core and trusses. Partly because trees don't have cores and trusses. Also, partly because it's an insult to laymen. I'm a layman. A lot of the NIST report is greek to me. But I can certainly understand the structure of the WTC without delving into plant life.

Not only is it inaccurate, but it's insulting for someone to suggest I'll better understand the structure of the WTC by explaining "well, a skyscraper is like a tree". I'm not five.

I saw a photograph on one of these sites where you can actually see the top of the WTC South Tower toppling just before the pancake.

Actually the top of WTC2 ROTATES as it falls. It isn't tipping. Don't forget the building had to fall through the four or five impact floors before there were any obvious exterior signs of collapse - the impact floors appear to have given way some time before, leaving only the exterior walls which gave way simultaneously.

So as the top collapses through 5 floors (about 60 feet by my calculations) it begins to rotate. Its primary momentum is down, however, not sideways. It is not tipping.

I would suggest that if you scaled up a tree trunk to the size of the WTC it would look quite porous as well. Secondly as I already pointed out, the fibrous nature of trees gives them their strength and toughness, very much like the fibrous nature of the steel space frame in the WTC.

Yes but how many times do we have to repeat that the WTC is mostly AIR? Is a tree mostly air? Or mostly wood? What do you feel offers better structural integrity and resistance to gravitational potential energy, air, or wood?

-Andrew

 

[einsteen]

The precise calculation should be much more difficult, non-elastic (or inelastic) means in fact that the impuls is conserved but not the energy, it can indeed be used to break a floor or to pulverize some stuff in the building ( I don't care about whether the core is iron or not and how complex the structure is, it's input-output that matters).

But if mass scatters away, obviously, no doubt about it, I'll post a reliable picture from BBC, not from a CT'ers site

http://newsimg.bbc.co.uk/media/images/41497000/jpg/_41497974_wtc_203bap.jpg

Roughly I would say that most of it scatters away from the building and that the block follows it's way down, but as I said the calculation needs to be modified. Greening's paper is without doubt a proper scientific paper, but it is under the assumption of that so-called progressive collapse or whatever the current name is. Some guys made some fun about the "growing block" that I talked about before, but in fact that is what Greening does although the block is in fact the initial falling upperblock plus al mass of the floors collapsed concentrated in a rectangular area (in fact with height=0, like an area of point masses)

This is a mathematical model (ideal situation) of the collapse. If one is able to estimate w(...,.n...,t...)=w? then one can calculate the collapse time. But even without any knowledge about that thing the minimum collapse time will increase, IMO dramatically, but we are not yet at the stage for hard conclusions.

Further the block is assumed to stay intact during its fall by F.R.Greening (it is hard to see from the videos, frames etc what really happened) but if you consider scattering (this means partly elastic and partly inelastic I think) the block will definitely damage during its fall and probably lose some mass during its fall, this is also a thing that should be added to the calculations.

Someone good with excel ? I don't use it I hate it.

 

[Belz...]

If you read back through the posts then you will see that it was you that introduced the tree analogy, NOT ME.

Again it is you getting hung up on trees.

No, you're the one who said this : "Regardless of the construction of the core (remember concrete is very good in compression and steel reinforcement is only there to resist tension) I am surprised at the mode of failure for the towers. My expectation would be that the floors would certainly pancake on each other leaving the core remarkably intact and that the top would topple over the core and fall to the side of the building. "[/QUOTE]

Gumboot's the one who brought up the tree analogy, because it is essentially what you're saying.

If that is too advanced a concept for you then say so because we are really going to have to go back to basics if you don't understand that.

Actually, I think saying the top should topple to the side pretty much IS an over-simplification of the problem.

 

[Belz...]

Strawman.

That wasn't a strawman. Get your fallacies straight.

Belz didn't make a point. He tried to analogise my opinion with a cartoon the motive of which is clear.

Of course my motive is clear. I'm calling your BS.

And I'm still waiting for answer to this question:

Are you a structural engineer, sir ?

 

[gumboot]

The precise calculation should be much more difficult

I'm just curious... what is all this "calculation" intended to determine?

Is the question "is there enough kinetic energy in the building to cause total collapse"?

Because if it is, this seems a bit pointless. The building is made up of a lot of small componants. Each of those componants has gravity acting upon it. The ONLY thing preventing each of those componants from falling to the ground is the overall structural integrity.

As soon as collapse occurs, the upper componants fall on those beneath, disrupting structural integrity. Hence all those componants fall. As they fall they in turn disrupt the structural integrity of the componants beneath.

I really don't see that a great deal of energy is actually REQUIRED.

I think of it like a collection of dominoes. If you take those elaborate structures they create and then knock over, the amount of force required to knock over each of those dominoes independently would be fairly substantial. but you don't. You only need to knock over one. That upsets the structural integrity of the one beside it, so that one topples, and it upsets the integrity of the one beside it, and so on.

You can cause the entire "structure" to completely fail simply by knocking over one.

-Andrew

 

[Belz...]

But if mass scatters away, obviously, no doubt about it, I'll post a reliable picture from BBC, not from a CT'ers site

http://newsimg.bbc.co.uk/media/images/41497000/jpg/_41497974_wtc_203bap.jpg

Roughly I would say that most of it scatters away from the building and that the block follows it's way down,

Einsteen, you can't simply look at a still from the collapse and guess that "most of [the mass] scatters away from the building". That's just impossible. As usual, you guys try to make your armchair analyses of photos sound authoritative.

 

[einsteen]

@gumboot

I know the domino stones since I was 8 years old

@Belz

Of course this is some bla bla roughly talk with some pictures, but the factor w should be <1. And please I'm not "you guys", I'm no CT"er, I'm not a conspiray thinker or whatever. I've never been on the Loose Change board only on a Dutch politics board that has a thread in which also everyone believes in

http://frogstar.soylentgeek.com/wav/DAPLANE.WAV

 

[Belz...]

Of course this is some bla bla roughly talk with some pictures, but the factor w should be <1. And please I'm not "you guys", I'm no CT"er, I'm not a conspiray thinker or whatever.

Doesn't matter. You analysis is consistent with those who embrace that theory: look at pictures, make sense of it using limited skills and knowledge, and then claim that something's amiss.

As far as I can tell from that picture, there could be ANY percentage of the building beign ejected to the side. 1% or 90%. It just isn't conclusive at all.

 

[einsteen]

Doesn't matter. You analysis is consistent with those who embrace that theory: look at pictures, make sense of it using limited skills and knowledge, and then claim that something's amiss.

As far as I can tell from that picture, there could be ANY percentage of the building beign ejected to the side. 1% or 90%. It just isn't conclusive at all.

Thanks Belz, you admit it could be any percentage, we agree!

 

[TjW]

No. It can't be "any percentage".
There are values for the mass of the towers. There are values for the mass of the rubble carted away.
Subtract one from the other and you have an upper limit on the mass that was pulverized and blew away as dust, either during the fall or during the cleanup.
Drywall pulverizes more easily than concrete, so the mass of the drywall used in construction should be subtracted from the dust cloud estimate.
Presumably, any force that would crush concrete would also crush drywall.
That will give an upper limit to the amount of pulverized concrete.

It won't tell you how much was crushed to less than 100 microns, but your argument from incredulity seems to stem from pictures of the cleanup that don't have "enough" rubble in them, and pictures of the collapse ejecting clouds of dust.

 

[Architect]

wrt providing credentials:

They can add weight to ones credibility, but that said, If William Rea is to announce his, than all those debating him should be forced to as well.

TAM

Deal.

BSc(Hons) Upper Second in Architectural Studies
B.Arch in Architecture
RIBA
ARIAS
ARB
FSA Scot (but that's not relevant)

Right, your turn.

 

[rwguinn]

Deal.

BSc(Hons) Upper Second in Architectural Studies
B.Arch in Architecture
RIBA
ARIAS
ARB
FSA Scot (but that's not relevant)

Right, your turn.

BSME, Mechanical Engineering
Registered Professional Engineer, Colorado
Staff Engineer, major aerospace Co.
Next?

 

[kevin]

BSME, Mechanical Engineering
Registered Professional Engineer, Colorado
Staff Engineer, major aerospace Co.
Next?

BSEE (Electrical Engineering). I spent 4 years doing electrical engineering mostly doing building power distribution systems. I changed to computer support before taking my PE tests although I had my EIT. I work for a large architectural/engineering consulting firm.

 

[T.A.M.]

I guess I might as well join in, for what it is worth...

Diploma Electronic Engineering Technology (3 year)
Bachelors of Medical Science (Hons)
MD
CCFP
(Hence why I leave most of the physical science to you guys)


TAM

 

[GlennB]

I'm just curious... what is all this "calculation" intended to determine?

Is the question "is there enough kinetic energy in the building to cause total collapse"?

Because if it is, this seems a bit pointless. The building is made up of a lot of small componants. Each of those componants has gravity acting upon it. The ONLY thing preventing each of those componants from falling to the ground is the overall structural integrity.

As soon as collapse occurs, the upper componants fall on those beneath, disrupting structural integrity. Hence all those componants fall. As they fall they in turn disrupt the structural integrity of the componants beneath.

Except for the components that are forced outwards and don't make contact with the standing components that remain. This is what einsteen is trying to discuss.

I really don't see that a great deal of energy is actually REQUIRED.

If a CT'er expressed such an opinion here they would be quietly put in their place. "I really don't see..." is just waffle. Have you done the calculations? Please present them.

I think of it like a collection of dominoes. If you take those elaborate structures they create and then knock over, the amount of force required to knock over each of those dominoes independently would be fairly substantial. but you don't. You only need to knock over one. That upsets the structural integrity of the one beside it, so that one topples, and it upsets the integrity of the one beside it, and so on.

So you're likening a 400m steel-framed building, with considerable cross-bracing, to a horizontal line of dominoes each of which is unconnected to its neighbour? Lines of falling dominoes don't accelerate. The analogy is flawed in so many ways it's nearly pointless discussing it.

You can cause the entire "structure" to completely fail simply by knocking over one.

A CT'er would point out that the Windsor building in Madrid suffered some collapse in the upper levels but maintained its integrity.


-Andrew

It's fair to analyse your post the way CT'ers posts get analysed.

 

[Belz...]

Thanks Belz, you admit it could be any percentage, we agree!

No, we don't, and I'm starting to wonder if your reading ability isn't impaired.

First and foremost, you've forgotten the dots after the "z".

And second, I said it could be any percentage, based only on looking at the picture. You, on the other hand, claim that MOST of the top portion definitely is ejected to the side. I claim that you cannot have such certainty. How you can summise that we agree on this point eludes me.

 

[Belz...]

wrt providing credentials:

They can add weight to ones credibility, but that said, If William Rea is to announce his, than all those debating him should be forced to as well.

TAM

Master of flame wars. I have no other credentials. I'm just a computer programmer who's equipped with logic and reasoning skills beyond those of a common household rat.