The Progressive Collapse Challenge

Originally posted by HowardRoark
Unfortunately, since these were the more traditional I-beams and not the floor trusses used in the WTC construction, it is not really possible to compare the two situations.

If it came down to it, Howard, I'm sure you would call foul on a different paint scheme if you could, just to try to save your theory the embarrassment of being compared to what really happens to steel skyscrapers on fire.

And seismic codes? I have a feeling that if that 17-hour fire damaged those 26 floors as badly as you allege fire damaged the WTC, adherence to even the most strict seismic code wouldn't save that building, as those 26 floors would've came right down at some point during those 17 hours.

This post is in response to a post by boredom on this thread.

Originally posted by boredom
For the sake of argument lets assume you have more knowledge of a subject than you actually do? Fine. For the sake of argument lets assume that I'm God so therefore I'm right.

The point was that information is information, and rather than focusing on who is saying it, try to focus on what is being said.

It's weak to attack information by harrassing the person who's presenting it. If I'm not mistaken, that's called an 'ad hominem attack' or some such. For the sake of argument, take what I am saying seriously whether or not I have enough degrees to satisfy your unreasonable and hypocritical requests.

You can't "for the sake of argument" yourself a few degrees and knowledge of a subject. It *may* be a fact, but my point is that YOU can't determine that it is a fact or not because you don't have the background to refute the word of a subject matter expert.

Then why argue with me? You wouldn't know any better. But like I said, facts are facts. If your criteria for proof is simply who says what, then ATS isn't for you, bud.

Originally posted by bsbray11
So you think that vibrations going down the building somehow caused this?

And yet there were no seismic readings from the area until the debris started hitting the ground. Look at that picture. Again, you're saying "vibrations," for which there is absolutely no evidence, did that

Let me rephrase. By vibrations I mean "the upper floors collapsing". Drop a cinder block on the floor. It causes vibrations that shake the floor. The cinder block won't do any real damage because the floor is strong enough to withstand the weight.

I got what you said the first time. The problem is that it's ludicrous. Not only would it be next to impossible (if not impossible outright) to produce enough energy from such vibrations to pulverize concrete into dust and then eject it over 100 feet laterally from a WTC tower, but there were also squibs that were as far as 50 floors below the collapsing regions of the buildings. If you would like to prove scientifically that this is possible, then go ahead and try, and be sure to post back here when you have accounted for the vast amount of energy that would've had to have been present.

In this case you have numerous floors of a building that collapse when the supports of one of the lower floor fail. The entire top section falls and strikes the next lower floor which immediately fails due to the force of many tons of weight suddenly striking it.

It isn't a complicated process really.

And this has nothing to do with the squibs. It's simply the Pancake Theory. The Pancake Theory does not accommodate for squibs.

Again, not enough force in your so-called "vibrations" to explode concrete dust from a WTC tower and send it over 100 feet out. I don't even think I have to detail how insanely ridiculous it is.

I don't need to prove it because the explanation I'm giving is direct from people with extensive knowledge on the subject. Read some documentation on how the building collapsed. What I'm saying comes directly from that documentation.

Nah; sorry. There have been no official explanations of the squibs, and nor have there been any logical explanations offered by "debunkers" that follow the official story.

So far I've seen explanations of: the squibs were digitally placed on the footage, the squibs were caused by air pressure, the squibs were "smudges" on the footage (wtf?), and now, that the squibs were caused by the vibration of the buildings, which somehow managed to shoot this mysterious concrete dust way out into the air laterally. Why can't people just accept the obviousness of some sort of explosive charge? It's not that big of an issue to come to grips with. Conspiracies aren't that uncommon in history.

Perhaps it was aliens that did it. =P

There's just as much evidence going for your suggestion here (ie, absolutely none), as your suggestion of "vibrating" buildings violently ejaculating concrete dust so far out into the air.

If you want to believe it's all a conspiracy and that the US government was behind it, fine. That's your right as a citizen of this country, but answer this.

Where are the people who were on the plane that hit the pentagon? Where is the missing plane? What about the passengers on flight 97? was that all faked as well?

[edit on 8-9-2005 by boredom]

Flight 93's (not 97) little heroic episode was likely written up like a good fiction, judging by the witness and other testimonies that directly contradicting the official story by suggesting Flight 93 was shot down. And Donald Rumsfeld slipping and saying it himself later. Plus the fact that the plane was spread out over so much land like it'd been blown right out of the sky. But my guess is that all those passengers died about 4 years ago nonetheless, just as so many people in the WTC complex died, and just as so many people continue to die in Iraq and Afghanistan.


Ultimately, if you want your explanation of beyond-extreme vibrations in the WTC towers to be believed, you're going to have to prove that (a) such vibrations actually existed in the towers during collapse, (b) such vibrations could produce the amount of energy necessary to pulverize the concrete slabs within the building and then eject them many, many feet laterally out into the NYC sky, and (c) they did produce that amount of energy at the WTC complex on 9/11, and (d) that those vibrations, with the necessary amount of energy, could somehow cause the squibs without any other noticeable effects on the buildings (ie, no further bending of columns or buckling, etc., etc., but just random explosions bursting out of the buildings).

If you can provide that, I'll believe you, but until then,



nothing of or sympathetic to the government's story has explained these massive explosions.

[edit on 8-9-2005 by bsbray11]

Oh, I haven't presented this detail yet. I suppose that you all know how buildings are demolished. Well, here is one video to be sure:

koti.mbnet.fi...

As you see, explosives explode BEFORE building starts to collapse, right? Dust from outer wall has flown long distance before you can even see the building to move. Well what do you think that would happen in WTC 2, when it has kinda big hole in it's wall and explosives are exploded? Shouldn't there bee clear pressure wave from the explosives? Air was full of smoke, I think that if they started the collapse by explosives, I should be able to see huge smoke clouds bursting out before tower even moves.

What I'm trying to say is that WTC 2 started to collapse clearly whitout explosives. Look closely to the collapse of WTC 2. When you can see first signs of explosives? I'd say that about one second after the building started to collapse. And yet smoke isn't comming out so fast...

BTW here is a tower that fell from top to bottom: koti.mbnet.fi...

Result would have been the same if we just knocked one stick away. That tower doesn't have core...

Fair point about the delay. Consider the many eyewitness reports of detonations at the foundation shortly before the collapses and you might have found an explanation for the missing delay. And while we're at it, in the 2 slow-mo reruns of that demolition, watch the explosive ejections closely and compare them to WTC footage. I'm sure we can agree that a fair amount of explosives provides energy several magnitudes greater than initial kinetic energy of a purely gravity driven collapse, so how come both instances (of ejections) look entirely similar?

Originally posted by msdos464
Shouldn't there bee clear pressure wave from the explosives? Air was full of smoke, I think that if they started the collapse by explosives, I should be able to see huge smoke clouds bursting out before tower even moves.

If the towers were conventional demos then you could expect that, but I don't think anyone is arguing that the tower destructions were conventional demos. Maybe WTC7, but not the first two. Given who would've had to have performed the demolitions, it shouldn't at all be ruled out that unconventional methods and charges were used, including explosives that the public would not be familiar with.

The collapse of WTC2 can be described as having two clearly different events, differentiated by the presence of two distinct types of momentum. At first, the building falls outwardly and at an angle, just as one would expect from a skyscraper falling by natural means. This goes on for about 2.5 seconds, until the angular momentum completely disappears. This is a violation of a basic physics law, btw, since angular momentum is conserved until acted upon an unbalancing force, which clearly would have been equal and opposite in this case, and yet such a force did not exist. This suggests the whole fulcrum was shattered in one instant by something other than the cap (as long as the cap touched, there would be a pivot).

When the angular momentum disappeared, the downward collapse began, which displayed the more basic demolition characteristics of symmetry, lack of lopsiding, lack of retardation/loss of momentum, pyroclastic flows, squibs, etc.

As to what events led directly to the first stage of the collapse of WTC2, the angular momentum, I couldn't say. That part looks totally natural, and if the fires weren't so puny, and the collapse continued in that fashion, I wouldn't see much wrong. There's little question that a more conventional method was being used when the strictly vertical collapse began.

If you get here, you'll find a close-up of the collapse of WTC2. Watch it. You'll see the results of the initial tilt on that corner of the building, and then you'll see an explosion erupt from within the building, going outwards, and then it's all puffs of dust from there on. Again, that close-up: webfairy.org... .

BTW here is a tower that fell from top to bottom: koti.mbnet.fi...

Result would have been the same if we just knocked one stick away. That tower doesn't have core...

I'm glad someone's finally attempted the challenge, but check out the 4th item of the challenge here.

Being able to withstand 100 mph winds requires the structure to be less flimsy and easily knocked-over, obviously.

I have to say though, that's a nice representation of what NIST, etc. is putting forward. With the sheets representing floors, and the trusses failing to cause the columns to give way.. Even the missing core is a nice touch, because early pancake theorists ignored/overlooked the fact that a massively strong core did exist. It's like the official story's warped logic wrapped up into a work of art, and though it's nice, it's also clear that it wouldn't be very relevant to the actual WTC collapses. Again, nice, man.

At first, the building falls outwardly and at an angle, just as one would expect from a skyscraper falling by natural means. This goes on for about 2.5 seconds, until the angular momentum completely disappears. This is a violation of a basic physics law, btw, since angular momentum is conserved until acted upon an unbalancing force, which clearly would have been equal and opposite in this case, and yet such a force did not exist.

And you are saying, that explosives can break even physics laws? Would bombs have stopped it?

Oh, I was meaning WTC 1 when i speaked about WTC 2... but the beging of collapses were rather similiar (when looking at smoke movement). Not a big deal.

About that tilting.. It didn't stop rotating when it started to move down, spinning just doesn't accelerate anymore. When it's tilted enough, core bends so much that it gave up. Then tower's upper section begun to fall.

Originally posted by msdos464
And you are saying, that explosives can break even physics laws? Would bombs have stopped it?

No; what I meant was, if they came down via gravity alone, a physics law would've been broken there. The bombs, in destroying the fulcrum, broke no laws and yet still stopped the tilting.

Oh, I was meaning WTC 1 when i speaked about WTC 2... but the beging of collapses were rather similiar (when looking at smoke movement). Not a big deal.

Yeah, same things but WTC1 tilted much less obviously. I would imagine that the tilting in WTC2 was rather undesirable, given WTC1 looked much more natural without such a tilt.

About that tilting.. It didn't stop rotating when it started to move down, spinning just doesn't accelerate anymore. When it's tilted enough, core bends so much that it gave up. Then tower's upper section begun to fall.

Can you clarify this a bit for me? I'm not sure I understand what you mean with the core giving up relating to a negative acceleration with the caps. The cap does move more in the collapse after the initial momentum loss, when it starts rolling around on top of the falling floors and all of that, but watch it and count '1 mississippi 2 mississippi' or however you were taught to count seconds, and when you get around 2 and a halfish, you should notice no more tilting outward. At the same time, grey puffs start coming out of the building in rows floor by floor.

I gotta go sleep now... but do you mean that bombs could provide a force to stop that tilting? If not, what's your explanation then?

I'll try to make a graph where is time and angle tomorrow.. Unfourtunately I don't have a video where South tower (WTC 2) could be seen straight from the side to measure the angle.

Basically he's saying that bombs would destroy the fulcrum, but the building collapsing would not have.

I know, it doesn't make any sense to me either.

Originally posted by msdos464
I gotta go sleep now... but do you mean that bombs could provide a force to stop that tilting? If not, what's your explanation then?

Not so much a force, but taking away the fulcrum. For the caps to tilt with angular momentum, they have to pivot off or something, or else they'll just fall straight down. When the lateral charges went off on the floor that a cap was pushing off of, the material that was being used as a fulcrum was immediately blown away and the cap lost its fulcrum and thereby its angular tilt. That's when the cap lost its angular momentum and just dropped.

I'll try to make a graph where is time and angle tomorrow.. Unfourtunately I don't have a video where South tower (WTC 2) could be seen straight from the side to measure the angle.

Try this video: www.911research.com...

On that one, the momentum is lost at around 5 seconds. Play around with the frames, going back and forth, around there, and watch the corner of the top of the cap.

Originally posted by LeftBehind
Basically he's saying that bombs would destroy the fulcrum, but the building collapsing would not have.

I know, it doesn't make any sense to me either.

The "building collapsing" wouldn't make sense because as long as there is contact, there is a pivot.

You can't have a mass crush its own fulcrum without touching that fulcrum, can you?

There are frames i used (i took every 10th frame from the video)

msdos464.no-ip.com...

I scaled frames to 800x600 resolution and used paint to draw lines and put line's x and y coordinate changes to excel table to calculate slope and angle.

msdos464.no-ip.com...

At frame 21 and 22 i couldn't draw the line anymore:

msdos464.no-ip.com... 21.jpg

And the data is here:

msdos464.no-ip.com...

As you see, drawing that line is little inaccurate, but it clearly shows that tower didn't stop tilting even when it begun to fall. Black line is sliding average of 2 adjacent points.

After frame 11 (actually frame 110, because i took every 10th frame) rotating speed doesn't accelerate anymore, it stays same.

I feel I need to shed some light on torque and the conservation of momentum here: Torque requires a pivot: M = r x F. No pivot, no r, which quantifies the distance between the pivot and the center of mass of the object being rotated.

Conservation of momentum doesn't require a pivot however, objects in motion don't accelerate/decelerate unless acted upon by force. As such, physics would suggest (or rather dictate) that the cap experienced an increase in angular velocity (due to torque) as long as the pivot existed, followed by rotation with constant angular velocity as the pivot desintegrated.

So, as we could witness that at some point the pivot must've vanished, we should be wondering how the cap, without any major contact to the lower structure acting as pivot, was able to crush said structure. Your call...

Surely it would be expected for the area acting as a pivot to fail, after bending tremendously and having most of the weight from the cap transferred onto it?
I'm not sure what else would be expected of it really.

Shows your grasp of physics. Like clinging onto a straw.

If the cap was supposed to crush the structure beneath, it would have had to make actual physical contact of a rather violent nature. I'm not talking about one isolated space of it, but all of the subsequent intact structure all the way down. Applying force to an object asymetrically, i.e. in a way that doesn't line up the direction of the force with both pivot and center of mass causes torque (or, in short: M = r x F). I think it's safe to say that with the tilted cap, the known direction of gravitic forces and the pivot (speaking x,y wise) being somewhere around the core, the prerequisites for having no torque at any point during the collapse were clearly not met. So there goes your explanation...

[edit] inserted M = r x F to add some precision to my verbal illustrations.

[edit on 3-1-2006 by Lumos]

Originally posted by Lumos
As such, physics would suggest (or rather dictate) that the cap experienced an increase in angular velocity (due to torque) as long as the pivot existed, followed by rotation with constant angular velocity as the pivot desintegrated.

Oops! Nevermind that, msdos. Sorry man, I'm getting terms and their concepts mixed up.

So, as we could witness that at some point the pivot must've vanished, we should be wondering how the cap, without any major contact to the lower structure acting as pivot, was able to crush said structure. Your call...

Exact same ultimate problem, though.

As you know, Fr = Ja, where a is the acceleration of rotation speed and J is inertia moment (i'm not sure is this correct term..)

Tilting tower's inertia moment is m*l^2 / 3, F = mg, and a we can calculate from video. So therefore we can define r, wich tells us the location point that supported tilting tower. Cool So, all we have to do is know the mass of tiling tower and rotation acceleration.

Be careful with the term "F r" though, it's valid only when F and r are orthogonal. Otherwise, it's "F x r" (vector product) - you can simplify that somewhat in a 2-dimensional case as "F r sin b", b being the angle between vectors F and r.

I know... I've calculated that:

r = (0.5s-x)cos(a)+0.5h*sin(a)

s = 63 m, wich is the width of the tower
h = about 100 m, the height of the tilting tower (upper portion)
a = tilting angle
x = how far from outer wall tilting point is

Force stays same all the time (mg).

Ofcourse some of the energy goes to breaking structures etc... It doesn't matter that tower's upper portion starts to fall, Fr=Ja says genuine.

I'd say that the tower fell like this: koti.mbnet.fi...

I tried to get same view as in "south tower collapse.mpg" video.

Not sure about the linear pivot "trajectory", good job nonetheless. The question is where to go from here, as the caps' actual mode of descent can't be reconstructed from the videos.

The cap did not remain intact. I would say it was long gone even half way through the collapse.