WTC: Rate of Fall (rate of crush)

[gerrycan]

A few things to note - 3.7m is NOT 2 floors, it is 1 floor. How many buildings do you know of that have ceiling heights of less than 1.35m ???
Also, Bazant supports the official narrative, unlike me. What I was posting debunks what he supposed in his analysis.
I think we are done here.

 

[Mick West]

Now now chaps, let's try to stick to the facts and avoid sniping please.

 

[Mick West]

A few things to note - 3.7m is NOT 2 floors, it is 1 floor. How many buildings do you know of that have ceiling heights of less than 1.35m ???
Also, Bazant supports the official narrative, unlike me. What I was posting debunks what he supposed in his analysis.
I think we are done here.

What, when did we get done? What was the result?

 

[gerrycan]

What, when did we get done? What was the result?

I just mean I am done with that sort of debate with jazzy, it is not why i came on here for, and I salute the way others conduct themselves on here, it is refreshing.

 

[Pete Tar]

The ceiling is the floor of the next level.

(I don't know if that's relevant to the context, just noting).

 

[Jazzy]

A few things to note - 3.7m is NOT 2 floors, it is 1 floor. How many buildings do you know of that have ceiling heights of less than 1.35m? Also, Bazant supports the official narrative, unlike me. What I was posting debunks what he supposed in his analysis. I think we are done here.

I will try again.

You said previously: "it is worth remembering that we are presuming that a whole floor (3.7m) of the tower just disappears and allows the block to drop at g." Remember?

My oft-repeated question is: "if a whole floor "disappears", then doesn't the floor above effectively drop two floors?"

It's a simple question. Why can't you give me a simple answer?

Perhaps because of this:


You can see the consequences of a floor detaching, the whole face of the tower puckering inwards, and the tower top falling away from the POV.
When that floor detached, it struck the floor beneath. The floor above (attached to the tower top) then fell two floors.

Floors had already detached elsewhere, so it wasn't exactly a novelty by this time.

I just mean I am done with that sort of debate with jazzy, it is not why i came on here for, and I salute the way others conduct themselves on here, it is refreshing.

What "debate" with me? How did I miss it?

 

[Boston]

It doesn't twist as dramatically as in the simulation, but that's not actually an important difference. What is important is all the things leading up to when the exterior started to collapsed.

There's too many variables and unknowns to accurately model the chaotic collapse. It's like simulating a break in pool. You could take a photo of a rack, measure the weight of all the balls, the coefficients of friction and restitution, the incoming position and velocity of the cue ball - and then plug it all into a simulation. But youa re not going to replicate what happened. You'll replicate the basics, some balls from the rack will scatter. But it's impossible to replicate where the ball will end up in a simulation, or even their initial trajectories.

Yah I think thats were a lot of disagreement lies. To me they are arguing the invisible and and acting like its definitive, even though those invisible things that "may" have occurred don't lead to an accurate depiction of the collapse. That accurate depiction being the test of the hypothesis, and it failed, in both models. Its kinda odd they chose to focus on arguing something for which there is absolutely not one shred of physical evidence. How can you even respond to that within a reality based discussion.

I think we should stick to discussing what we can see happening rather than what some folks would like to assume happened before or after the events for which we do have some evidence. Yup, the pent house collapsed, why, no idea, how far down past the parapet wall did it go, no idea. But we can see a kink develop nice and perfectly before all four corners go nice and perfectly.

Tell you what, I'm not sure if the start a new thread function is working but I saw a video thats perfect to define what the problem is with this fall time argument. Some people like to start the clock loooooong before the building actually fell.

Lets see if I can make this thing work.

 

[Mick West]

It pretty clear the collapse of WTC1 occured over several floors

 

[Jazzy]

Yah I think thats were a lot of disagreement lies. To me they are arguing the invisible

Stop you there. There are some things visible that aren't being seen.

and acting like its definitive, even though those invisible things that "may" have occurred don't lead to an accurate depiction of the collapse.

In the case of the billiards break, it may not be necessary to depict perfectly what happened.

That accurate depiction being the test of the hypothesis, and it failed, in both models.

And here is a case in point. It matched the timeline, and there was a small error towards the end of the simulation. That's like 100%, and then 95%, which you are calling a fail. Serious, man, you cannot be being.

Its kinda odd they chose to focus on arguing something for which there is absolutely not one shred of physical evidence. How can you even respond to that within a reality based discussion.

Hey, there was hours of video and pictures of a f------g great pile of rubble. What are you talking about?

I think we should stick to discussing what we can see happening

I'm happy to discuss what you think you see happening because our perceptions differ so greatly. You really do not see what I do see, I get that. This isn't a time to stop talking.

rather than what some folks would like to assume happened before or after the events for which we do have some evidence.

Yup, the pent house collapsed, why, no idea, how far down past the parapet wall did it go, no idea.

That just shows where you, in particular, cannot live with what you know it must mean. It's an abrogation of your stated responsibility to discover truth.

But we can see a kink develop nice and perfectly before all four corners go nice and perfectly.

And this your get-out clause. They lied, and the simulation failed.

It pretty clear the collapse of WTC1 occured over several floors.

Then it is quite clear that any calculation using a single floor drop is a complete waste of time and effort, isn't it?

This also applies to WTC2. It looks like the far side fell further faster than the side we see, otherwise it wouldn't have been able to take a 20 degree tilt. And the side we see falls two floors.

Truthers are ill-advised to try to "calculate" any of this, when they have trouble actually seeing what there is to be actually seen in the first place.

It's that "six blind men asked to identify an elephant" scenario.

 

[Boston]

I was referring to WTC 7 in my last. The idea that there is a presupposition from which false data is derived, rather than obtaining only visual data from what evidence there is and then developing a hypothesis from that data.

 

[Jazzy]

You've just left me gasping for breath. Can't think why...

 

[gerrycan]

Then it is quite clear that any calculation using a single floor drop is a complete waste of time and effort, isn't it?



Truthers are ill-advised to try to "calculate" any of this, when they have trouble actually seeing what there is to be actually seen in the first place.

Okay Jazzy, I gave you the figures for a one storey drop, figure out the math for a 2 storey drop, as you seem to be clinging to this theory, though why 2 storeys would just disappear is beyond me. Be interesting to see your work though. Look forward to it

 

[Jazzy]

Okay Jazzy, I gave you the figures for a one storey drop, figure out the math for a 2 storey drop, as you seem to be clinging to this theory, though why 2 storeys would just disappear is beyond me. Be interesting to see your work though. Look forward to it

I did it a few years back. I have no record of it now. Not that it's difficult.

Using V^2=U^2+2*G*s, where U=0, G=9.81 meters/sec^2, s=7.34 meters, then V=sqrt(2*9.81*7.34)=12.0 meters/sec, or 26.8 mph.

The assumption of G nowhere near approaches the actual acceleration at the start of collapse, because the structures actually failed at some unique point, and had to spread their failure away from that.

One thing we can be sure about is that this point of failure was not at the dead center of a tower.

Failure (of the lateral support of the floors) from a point somewhere against its exterior columns would have given the WTC2 tower a moment to lean against, which it did.

Failure (of the lateral support of the floors) from a point somewhere against its interior columns produced an interesting motion of the central mast of WTC1, but obviously less in the way of lean, with the smaller moment.

That's as far as a calculator will allow me to reach.

 

[Mick West]

Here's a handy diagram illustrating the likely progression of the collapse


Does not really deal with how the core columns failed, but the idea is that it's the floors and perimeter failing first, stripping lateral support from the core.

 

[Boston]

So where is the explanation of what happened to the central cores, the roof lines on these buildings fell intact. There was no punching through at the roof line of the core columns. In your diagrams, there is no accommodation for the failure of the core.

 

[Mick West]

So where is the explanation of what happened to the central cores, the roof lines on these buildings fell intact. There was no punching through at the roof line of the core columns. In your diagrams, there is no accommodation for the failure of the core.

Yeah, it's a bit of a poor diagram in that regard, but it illustrates the exterior columns peeling away, and the accumulation of mass by the collapse front.

The initiating events of collapse involves the core columns failing around those floors, so there would not be "punch through" until after the roof had fallen below the collapse initiation floors, and by that point the core was already failing. There obviously were some core columns that collapsed well after the floors and exterior though.

Here's the accompanying article for that diagram:
http://www.csicop.org/si/show/the_9_11_truth_movement_the_top_conspiracy_theory_a_decade_later/

 

[Boston]

I think you meant "the assumed initiating events of the collapse". Since we have no actual data concerning the pattern of failure. But there must be a mechanism for those columns all failing at once and progressive failure requires that as one column fails, load is transferred to another. That load must overcome all connective structures and then cause the failure of the next column, and so on down the line, 48 times, or thereabouts. some few "may" have been damaged by the impact. Which takes time. Yet the failure can be seen to occur at an extremely high rate of speed. Something within the time frame of just a few frames of film. Film typically shot at about 30 frames a second.

It might be a good time to point out that structural steel doesn't like to shatter, it tends to bend, particularly when subjected to heat. So heat deformation is the more likely scenario than a sudden and catastrophic fracturing of all the steel within just a few tenths of a second.

If I'm understanding you correctly your thinking that the cores all broke at the point of impact and so dust and debris obscured the observation of those core columns ? Cause I'd think that there are two major issues with this hypothesis. One is that the floors were supported by sections out to the outer walls from ledgers embedded in the core columns, these sections were unlikely to all let go at once, I'd also want to see the prints before assuming that they would all be able to slide past the core in the manor you've depicted. again for continuity the structure its most likely they extended past the core boundaries and out to the outer walls. The second issue I have is the that the core structure was massive, and wouldn't have been severely damaged by the impact.

 

[Mick West]

I think you meant "the assumed initiating events of the collapse". Since we have no actual data concerning the pattern of failure. But there must be a mechanism for those columns all failing at once and progressive failure requires that as one column fails, load is transferred to another. That load must overcome all connective structures and then cause the failure of the next column, and so on down the line, 48 times, or thereabouts. some few "may" have been damaged by the impact. Which takes time. Yet the failure can be seen to occur at an extremely high rate of speed. Something within the time frame of just a few frames of film. Film typically shot at about 30 frames a second.

If I'm understanding you correctly your thinking that the cores all broke at the point of impact and so dust and debris obscured the observation of those core columns ? Cause I'd think that there are two major issues with this hypothesis. One is that the floors were supported by sections out to the outer walls from ledgers embedded in the core columns, these sections were unlikely to all let go at once, I'd also want to see the prints before assuming that they would all be able to slide past the core in the manor you've depicted. again for continuity the structure its most likely they extended past the core boundaries and out to the outer walls. The second issue I have is the that the core structure was massive, and wouldn't have been severely damaged by the impact.

It was a combination of impact damage, weakening from the fire, and redistributed loads. You remember the fire was quite intense at the time of collapse



You can also see the perimeter columns bowing inwards here, for several floors below the fresh fire, which itself covers several floors - indicated the large number of flors incolved in the (hypothetical, but seeming quite likely) collapse initiating events.

 

[Jazzy]

So where is the explanation of what happened to the central cores, the roof lines on these buildings fell intact. There was no punching through at the roof line of the core columns. In your diagrams, there is no accommodation for the failure of the core.

The core columns couldn't punch through the roof because the top hat truss intervened. The top was an intact unit, and all the columns, interior and exterior failed by buckling beneath it.

Yeah, it's a bit of a poor diagram in that regard, but it illustrates the exterior columns peeling away, and the accumulation of mass by the collapse front. The initiating events of collapse involves the core columns failing around those floors, so there would not be "punch through" until after the roof had fallen below the collapse initiation floors, and by that point the core was already failing. There obviously were some core columns that collapsed well after the floors and exterior though.

The core columns didn't punch through the roof because the top hat truss intervened. The top was an intact unit, and all the columns, interior and exterior failed by buckling beneath it.

I think you meant "the assumed initiating events of the collapse". Since we have no actual data concerning the pattern of failure.

One man's data is another man's poison. Some of us can see what is happening.

But there must be a mechanism for those columns all failing at once and progressive failure requires that as one column fails, load is transferred to another. That load must overcome all connective structures and then cause the failure of the next column, and so on down the line, 48 times, or thereabouts. some few "may" have been damaged by the impact. Which takes time. Yet the failure can be seen to occur at an extremely high rate of speed. Something within the time frame of just a few frames of film. Film typically shot at about 30 frames a second.

I was going to explain, but you answered yourself. Perhaps you need to understand that all the surrounding columns were loaded close to their peak too, yet weren't loaded by the load that the failing column was taking. When it failed, they were.

It might be a good time to point out that structural steel doesn't like to shatter, it tends to bend, particularly when subjected to heat. So heat deformation is the more likely scenario than a sudden and catastrophic fracturing of all the steel within just a few tenths of a second.

Buckling is the predominant scenario. Fracturing and heat deformation aren't. Although creep and misalignment were consequential to the heating.

If I'm understanding you correctly your thinking that the cores all broke at the point of impact and so dust and debris obscured the observation of those core columns?

You aren't. They buckled.

Cause I'd think that there are two major issues with this hypothesis.

Yes.

The second issue I have is the that the core structure was massive, and wouldn't have been severely damaged by the impact.

Except that the towers were not vertical as they collapsed. This allowed the floors to strip the core bracing as they fell.

It was a combination of impact damage, weakening from the fire, and redistributed loads. You remember the fire was quite intense at the time of collapse. You can also see the perimeter columns bowing inwards here, for several floors below the fresh fire, which itself covers several floors - indicated the large number of floors involved in the (hypothetical, but seeming quite likely) collapse initiating events.

Indeed.

 

[MikeC]

I think you meant "the assumed initiating events of the collapse". Since we have no actual data concerning the pattern of failure. But there must be a mechanism for those columns all failing at once and progressive failure requires that as one column fails, load is transferred to another. That load must overcome all connective structures and then cause the failure of the next column, and so on down the line, 48 times, or thereabouts. some few "may" have been damaged by the impact. Which takes time. Yet the failure can be seen to occur at an extremely high rate of speed. Something within the time frame of just a few frames of film. Film typically shot at about 30 frames a second.

That is still "time".

Structural overload can be effectively instantaneous if the force is sufficiently great - the materials do not think about whether they are overloaded and contemplate how to fail - the more-or-less instantaneous application of a massively unsupportable force will cause a more-or-less instantaneous failure.

 

[Mick West]

That is still "time".

Structural overload can be effectively instantaneous if the force is sufficiently great - the materials do not think about whether they are overloaded and contemplate how to fail - the more-or-less instantaneous application of a massively unsupportable force will cause a more-or-less instantaneous failure.

Like:

There is practically no transition between the thin can supporting 100 pounds, and that same 100 pounds in near free fall.

Combined with

Three cans support 160 pounds (me). One can fails, the sudden uneven loading is too much for the other cans and they fail simultaneously, buckling near the bottom.

(Illustrating the principles only, of course).

 

[Boston]

There is no data to support the hypothesis that it was a combination fire and impact. There is zero definitive data proving any hypothesis. There has also been exactly zero testing of any hypothesis and move the hype forward into a working theory. All or nearly all evidence/data was scrubbed from the scene long before any detailed analysis could be conducted.

I remember that black smoke is an indicator of a oxygen starved fire, I also remember that dark orange flame is an indicator of low flame temperature. Also I do not see a complete involvement of any one floor nor do I see the total involvement of any number of floors. Pictured bellow is what I would call an intense multi story fire, one that I might add did not result in instantaneous global failure.

http://i.imgur.com/62XkN9t.jpg/http

Nor has anyone been able to show that more than a few columns bowed inwards prior to collapse.

 

[Boston]

Oh and we've been over the can hypothesis, I wonder if you can show any failure similar to any natural collapse with the can model or if it is imposible to do anythng at all with it but show this particular failure. Cause in a multifaceted system where you are trying to show the transfer of loading to successively failing members there is an opportunity for connective members to fail and part of the structure to remain intact. Where is this possibility within the can model ?

The model is in fact an inaccurate and disingenuous representation of the structure of the buildings.

 

[Boston]

That is still "time".

Structural overload can be effectively instantaneous if the force is sufficiently great - the materials do not think about whether they are overloaded and contemplate how to fail - the more-or-less instantaneous application of a massively unsupportable force will cause a more-or-less instantaneous failure.

You'd have to have some wildly improbably forces. lets look at a progressive bridge failure and see how long that takes.

 

[Boston]

Not worth the fight to try and get this into my last post. Deal is Mike here we have a large steel deck bridge failure. Notice how long it takes for the failure to stutter down the connective materials eventually taking down the entire thing.

Same thing is what I'd expect in the WTC 1&2. assuming it was in fact asymmetric damage accompanied by heat distortion. I'd also expect a partial failure of a large vertical structure rather than the linear failure of a suspension bridge

 

[Mick West]

The model is in fact an inaccurate and disingenuous representation of the structure of the buildings.

It's not a representation of the structure of the building. It's demonstrating the principle of instantaneous support loss in buckling (1 can) and the result of uneven load transfer (3 cans).

 

[MikeC]

You'd have to have some wildly improbably forces. lets look at a progressive bridge failure and see how long that takes.

not exactly the type of failure that is being discussed, and all not a sudden application of a massive overload - the overload built up over several minutes due to positive feedback from the bridges harmonic frequency and the wind.

I don't se how you could expect that to be related to anything that happened in any of the WTC collapses - I consider it completely irrelevant.

And I have actually studied the Tacoma Narrows failure - even did the math on it.....a couple of decades ago tho, so I'm not about to regurgitate it all!!

 

[Mick West]

Not worth the fight to try and get this into my last post. Deal is Mike here we have a large steel deck bridge failure. Notice how long it takes for the failure to stutter down the connective materials eventually taking down the entire thing.

Same thing is what I'd expect in the WTC 1&2. assuming it was in fact asymmetric damage accompanied by heat distortion. I'd also expect a partial failure of a large vertical structure rather than the linear failure of a suspension bridge

The bridge is hung from flexible cables that transfer the weight evenly to the bridge towers (which never fail). The buildings rest directly on essentially rigid columns. It's not even remotely the same thing.

 

[Boston]

Its a progressive failure of a multifaceted steel structure and it took a lot of time to "progress" through the structure regardles of the force involved. Gravity took over once the monolithic structure was compromised.

Progressive collapse does not proceed uniformly not does it proceed at a near instantaneous pace.

Can you show a single real life example of a progressive collapse other than the WTC site which is IMHO not representative of a progressive collapse

Oh and those towers Micks pointing out are acting like the columns in the trade center towers and as the load is removed from then they did not fall down. Just what I'd expect. Kinda like the exterior walls of WTC 7

 

[Mick West]

Its a progressive failure of a multifaceted steel structure and it took a lot of time to "progress" through the structure regardles of the force involved. Gravity took over once the monolithic structure was compromised.

What are you talking about? The collapse happened so fast that they didn't manage to get it on film. Everything else is just violent undulations of the roadway. Not collapse.

Oh and those towers Micks pointing out are acting like the columns in the trade center towers and as the load is removed from then they did not fall down. Just what I'd expect. Kinda like the exterior walls of WTC 7

No. The bridge towers are designed to be freestanding and support a massive load at the top without any lateral support. Utterly unlike the core towers, which rely on lateral support to keep standing, and have basically no load on top.


The towers above (Golden Gate Bridge) are 746 feet high, and each leg is 33 x 54 feet.

 

[Mick West]

Can you show a single real life example of a progressive collapse other than the WTC site which is IMHO not representative of a progressive collapse

 

[Mick West]

And to balance your bridge example:

 

[Boston]

I love love it, you do realize you just showed a video of a controlled demolition
Oh and watch the film of the T narrowws brindge it is very obvous the collapse isn't all that fast

 

[Mick West]

I love love it, you do realize you just showed a video of a controlled demolitionnnnnnnnnnnn

Of course I do. And one where they "pull" the building. So what? Are you suggesting this suggest that WTC1/2 were "pulled"?

 

[Mick West]

If you can't type, then don't post.

 

[MikeC]

Its a progressive failure of a multifaceted steel structure and it took a lot of time to "progress" through the structure regardles of the force involved.

So what?

Progressive collapse does not proceed uniformly not does it proceed at a near instantaneous pace.

Again...so what? Of course progressive is not instantaneous - it is progressive - like the collapse of all eth WTC towers - they all progressively collapsed - one bit after another.

The instantaneous failures occurred as components within het structure were overloaded - you can instantaneous failures in the Tacoma Narrows video at several points as the roadwat disintegrates.

Can you show a single real life example of a progressive collapse other than the WTC site which is IMHO not representative of a progressive collapse

At this point I am thinking that you do not actually understand what progressive means.

Oh and those towers Micks pointing out are acting like the columns in the trade center towers and as the load is removed from then they did not fall down. Just what I'd expect. Kinda like the exterior walls of WTC 7

Huh?? all of them did fall down??

 

[Boston]

ojchg'lakdf Oh annnnnd I think yuou forgot wind loading , kinda like they did

 

[MikeC]

now I'm getting even more confused - are you suggesting that wind loading was relevant to the WTC falling??

Tacoma Narrows was caused solely by the wind causing resonance - as I said this was a subject I studied over 25 years ago or so as an undergraduate - the math is covered by 1st year mechanical engineering courses!

I do not understand why you think it is relevant to a building collapsing under its own weight after structural damage.

 

[Jazzy]

The model is in fact an inaccurate and disingenuous representation of the structure of the buildings.

It wonderfully represents buckling, and progressive collapse, where the collapse of the first tin immediately causes the collapse of the other two.

This is the principle (buckling) which you still don't seem to understand. All the WTC buildings in question failed by buckling, as they lost the horizontal restraints of their floors. Transferred loads caused progressive buckling collapses, rapid ones in the case of the towers, but in three stages in the case of WTC 7.

 

[thedude953]

The buckling argument does not explain simultaneous synchronized collapse of the floors to allow the freefall or close to freefall speed during the first few seconds. we all understand it explains the collapse just not in the way It actually happened