• Quick note - the problem with Youtube videos not embedding on the forum appears to have been fixed, thanks to ZiprHead. If you do still see problems let me know.

OOS Collapse Propagation Model

Status
Not open for further replies.
JSanderO said:
A vertical tube which has its 4 side "fall away" needs to have them separate at the corners... correct?

The seems to have been a lateral outward force which directed the fall away to the outside.

What do you think it was?
Click to expand...

I don't think it was that precise. For example, on the left:

 
JSanderO said:
A vertical tube which has its 4 side "fall away" needs to have them separate at the corners... correct?

The seems to have been a lateral outward force which directed the fall away to the outside.

What do you think it was?
Click to expand...

Not the issue, really. I'm simply trying to differentiate between facts derived from observations, and conclusions derived from reasoning. The latter, like any scientific theory, should always be considered provisional. The model referred to appears to be the best we know to explain all the observations, but it's important to allow for the possibility that someone may come up with a better one.

Dave
 
ozeco41 said:
My starting premises are the two extremes of a vector range of possibilities:
1) At one extreme progression collapses can be legitimately explained by buckling or column crushing energetics as per the Bazant "Limit Case" and the valid extension of those into the generic Model that Bazant was pursuing in BV. Plus any other real event collapse where column buckling/"crushing" is the primary factor. (And this bit of disclaimer to show I'm not overlooking it - and other factors are a lower order of magnitude).

2) At the other extreme the WTC Twin Towers collapses progression stages were dominated by floor joist shear failure energetics. NOT column buckling/crushing. The same would apply to any other similar collapse - excuse the circularity i.e. any collapse which like WTC did not crush/buckle columns. (and other factors are a lower order of magnitude).

I think we are agreed those two as premises. If not please ask for more clarification/justification.
Click to expand...

Well, the reason I brought this up is that I don't (yet) accept the first premise (except in the sense that "at one extreme," floor spans begin at zero?). I believe it's virtually impossible in a conventionally designed building to crush columns by loading floors (with impact or otherwise), so your premise would require that with shorter spans, there would be proportionally more cases where columns directly received enough additional force to buckle. While there might be more columns crushed, having more columns also means each is less significant in the overall collapse. Also, as I said, I believe the total column load capacities and floor connection shear capacities depend on floor loads rather than on column spacing, so it's not immediately obvious to me that failure mode proportions would change much with different (practical) spacings.

And since we're apparently not going to hear any more about ROOSD from Major_Tom, have you given any thought to the supposed "funnel" effect? I think it's the second most misleading part of ROOSD. Most of debris went straight down because of gravity, not the perimeter wall, and furthermore whatever minor effect the wall had, it would have been exactly the same with shorter column spacing.
 
There was no "column crushing". When a few columns were left toward the last moment before "release" they saw loads exceeding their capacity... probably significantly so they buckled / bent over like a wet noodle. The other columns were probably pushed out of axially alignment and could not longer convey loads down. The loads were mostly floors and super imposed loads and when they are not supported... lo and behold... they fall down like humpty dumpty... and destroy themselves in the process going down.
 
Crazy Chainsaw said:
A theory needs to show whyD'Alembert's principal doe not apply if it is correct in this universe.

It should even apply to a falling mass inside a funnel effect.

I can think of two possible theories, but would like to hear others Ideas first.
Click to expand...

I'm not very familiar with the application of D'Alembert's Principle, though the classic example of where it breaks down is where friction is a significant contributor to the forces; but I don't think it's necessary to start jettisoning laws of physics just yet. In my experience, problems with classical mechanics generally stem from mis-specifying the system under consideration. And this is, I think, the problem with a 1-D model that ozeco41 is getting at.

In a 1-D collapse model, the debris can only accumulate between the top and bottom blocks. The prediction of the 1-D model is that the debris, in effect, crushes the bottom block while the top block rides on it. In some cases that may be a very good approximation; there are, for example, some verinage demolitions of concrete framed buildings that appear to show very much that behaviour. But in a real, 3D, steel framed building, where the support columns are a very small fraction of the cross-sectional area, it's trivially easy for the debris to outstrip the column collapse and fall between the columns, leaving the top block to continue to impact the bottom block.

I suggested years ago that there were at least four separate processes going on in the WTC collapses. Firstly, there's the internal collapse of the floors under the weight of the debris, which is fast because the floor connections absorb relatively little energy. Then, lagging behind it (as it must, because it's dependent on it), is the collapse of the perimeter columns, partly because their unbraced length is too great for them to remain stable, but also partly due to repeated partial impacts between top and bottom blocks - the micro-jolts seen in femr2's derivative data - for as long as the top block survives. Next, the hat truss must have impacted the core columns, destroying the former and at least a significant part of the latter, but again lagging behind the floor collapse. And finally, when everything else had progressed to ground level, the remnants of the core also fell due to excessive unbraced length and whatever damage they'd suffered from the earlier processes. And any analysis that doesn't consider all these aspects is not going to be accurate.

From a point of view of debunking conspiracy theories, none of this is particularly important, which is probably why it hasn't been extensively studied here; the debris alone can cause collapse, and nothing could have stopped it, so no more explanation is needed to exclude the necessity of explosive assistance to collapse propagation. It's also probably too complex to be tractable to analysis, which is why simpler models are generally used. But I think it may account for why those simpler models don't necessarily give the right answer.

Dave
 
Dave Rogers said:
I'm not very familiar with the application of D'Alembert's Principle, though the classic example of where it breaks down is where friction is a significant contributor to the forces; but I don't think it's necessary to start jettisoning laws of physics just yet. In my experience, problems with classical mechanics generally stem from mis-specifying the system under consideration. And this is, I think, the problem with a 1-D model that ozeco41 is getting at.

In a 1-D collapse model, the debris can only accumulate between the top and bottom blocks. The prediction of the 1-D model is that the debris, in effect, crushes the bottom block while the top block rides on it. In some cases that may be a very good approximation; there are, for example, some verinage demolitions of concrete framed buildings that appear to show very much that behaviour. But in a real, 3D, steel framed building, where the support columns are a very small fraction of the cross-sectional area, it's trivially easy for the debris to outstrip the column collapse and fall between the columns, leaving the top block to continue to impact the bottom block.

I suggested years ago that there were at least four separate processes going on in the WTC collapses. Firstly, there's the internal collapse of the floors under the weight of the debris, which is fast because the floor connections absorb relatively little energy. Then, lagging behind it (as it must, because it's dependent on it), is the collapse of the perimeter columns, partly because their unbraced length is too great for them to remain stable, but also partly due to repeated partial impacts between top and bottom blocks - the micro-jolts seen in femr2's derivative data - for as long as the top block survives. Next, the hat truss must have impacted the core columns, destroying the former and at least a significant part of the latter, but again lagging behind the floor collapse. And finally, when everything else had progressed to ground level, the remnants of the core also fell due to excessive unbraced length and whatever damage they'd suffered from the earlier processes. And any analysis that doesn't consider all these aspects is not going to be accurate.

From a point of view of debunking conspiracy theories, none of this is particularly important, which is probably why it hasn't been extensively studied here; the debris alone can cause collapse, and nothing could have stopped it, so no more explanation is needed to exclude the necessity of explosive assistance to collapse propagation. It's also probably too complex to be tractable to analysis, which is why simpler models are generally used. But I think it may account for why those simpler models don't necessarily give the right answer.

Dave
Click to expand...

DBB, would agree with you, you just described the computer model that was used to support
BLGB.
Except for D'Alembert's principal and friction, DBB, was not being mean to MT, he truly
Believed that D'Alembert's principal fully applied as has been shown in countless real world
Experiments, remember floors and parts can not fall faster than free fall.
 
Crazy Chainsaw said:
Except for D'Alembert's principal and friction, DBB, was not being mean to MT, he truly
Believed that D'Alembert's principal fully applied as has been shown in countless real world
Experiments, remember floors and parts can not fall faster than free fall.
Click to expand...


No, he wasn't being mean. He was quite open and honest about how he perceived the collapse progression process of WTC1. He was absolutely convinced that the BV and BL papers proved there could be very little crush-up of the 'upper block' in WTC1 and stated so openly many times. The quote once again:

"Major_Tom ---
Do you doubt Newton's Laws?
Do you doubt http://en.wikipedia.org/wiki/D'Alembert's_principle?
Do you doubt the applicability of the four simplifying assumptions in B&V?
If not, the conclusion of little early crush-up of zone C follows.
Further, the timing studies in BLGB show that most of zone C mass must have stayed on top most of the way down."
Click to expand...
from this post


Question 10: Within this quote does David Benson express the belief that the timing studies in BLGB shows that most of the zone C mass (the 'upper block') of WTC1 must have stayed 'on top' most of the way down, experiencing 'little early crush up'?

Question 11: Does David Benson state that little early crush up of the wTC1 upper portion directly follows from an application of Newton's Laws, D'Alembart's principle and the fact that the four simplifying assumptions stated in the paper BV can be applied to WTC1?



The answers appear to be: yes and yes,



When questioned repeatedly, he had no doubts about the WTC1 upper portion experiencing no significant crush-up.





David Benson on WTC1:

"OneWhiteEye --- I'm not the one with any doubts about the matter: there can be no significant early crush-up."
Click to expand...
from this post


Question 13: Within this statement does David Benson explicitly state that there can be 'no significant early crush up' and that he has 'no doubts' about that claim?



The answer to this question is yes. He had no doubts that the WTC1 upper portion experienced no significant crush-up. These quotes are from 2009, one year after BLGB was published.
 
Last edited:
Major_Tom said:
No, he wasn't being mean. He was quite open and honest about how he perceived the collapse progression process of WTC1. He was absolutely convinced that the BV and BL papers proved there could be very little crush-up of the 'upper block' in WTC1 and stated so openly many times. The quote once again:

from this post


Question 10: Within this quote does David Benson express the belief that the timing studies in BLGB shows that most of the zone C mass (the 'upper block') of WTC1 must have stayed 'on top' most of the way down, experiencing 'little early crush up'?

Question 11: Does David Benson state that little early crush up of the wTC1 upper portion directly follows from an application of Newton's Laws, D'Alembart's principle and the fact that the four simplifying assumptions stated in the paper BV can be applied to WTC1?



The answers appear to be: yes and yes,



When questioned repeatedly, he had no doubts about the WTC1 upper portion experiencing no significant crush-up.





David Benson on WTC1:


from this post


Question 13: Within this statement does David Benson explicitly state that there can be 'no significant early crush up' and that he has 'no doubts' about that claim?



The answer to this question is yes. He had no doubts that the WTC1 upper portion experienced no significant crush-up. These quotes are from 2009, one year after BLGB was published.
Click to expand...

That's because the more complex computer model and all the experiments to date on collapsing buildings predict D'Alembert's principal to be a significant factor, changing the
Structure should have no effect on that, the physical forces should remain the same.
 
Dave Rogers said:
I'm not very familiar with the application of D'Alembert's Principle, though the classic example of where it breaks down is where friction is a significant contributor to the forces; but I don't think it's necessary to start jettisoning laws of physics just yet. In my experience, problems with classical mechanics generally stem from mis-specifying the system under consideration. And this is, I think, the problem with a 1-D model that ozeco41 is getting at.

In a 1-D collapse model, the debris can only accumulate between the top and bottom blocks. The prediction of the 1-D model is that the debris, in effect, crushes the bottom block while the top block rides on it. In some cases that may be a very good approximation; there are, for example, some verinage demolitions of concrete framed buildings that appear to show very much that behaviour. But in a real, 3D, steel framed building, where the support columns are a very small fraction of the cross-sectional area, it's trivially easy for the debris to outstrip the column collapse and fall between the columns, leaving the top block to continue to impact the bottom block.

I suggested years ago that there were at least four separate processes going on in the WTC collapses. Firstly, there's the internal collapse of the floors under the weight of the debris, which is fast because the floor connections absorb relatively little energy. Then, lagging behind it (as it must, because it's dependent on it), is the collapse of the perimeter columns, partly because their unbraced length is too great for them to remain stable, but also partly due to repeated partial impacts between top and bottom blocks - the micro-jolts seen in femr2's derivative data - for as long as the top block survives. Next, the hat truss must have impacted the core columns, destroying the former and at least a significant part of the latter, but again lagging behind the floor collapse. And finally, when everything else had progressed to ground level, the remnants of the core also fell due to excessive unbraced length and whatever damage they'd suffered from the earlier processes. And any analysis that doesn't consider all these aspects is not going to be accurate.

From a point of view of debunking conspiracy theories, none of this is particularly important, which is probably why it hasn't been extensively studied here; the debris alone can cause collapse, and nothing could have stopped it, so no more explanation is needed to exclude the necessity of explosive assistance to collapse propagation. It's also probably too complex to be tractable to analysis, which is why simpler models are generally used. But I think it may account for why those simpler models don't necessarily give the right answer.

Dave
Click to expand...

Fore the benefit of the discussion, the only lecture video on D'Alembert principal I can find.
D' Alembert principle, D' Alembert Equation: http://youtu.be/PlbgIGH4kmE
 
Last edited:
Crazy Chainsaw said:
That's because the more complex computer model and all the experiments to date on collapsing buildings predict D'Alembert's principal to be a significant factor, changing the
Structure should have no effect on that, the physical forces should remain the same.
Click to expand...


It is because on a very fundamental level they truly did not understand what they were looking at.

For those who see authority as providing all the answers, that is a very hard pill to swallow. And there is no doubt that, on a very fundamental level, that simple fact produces a type of cognitive dissonance within an environment like JREF/ISF.

This thread, from the very first posts, is a perfect example of how this cognitive dissonance is manifested.
 
Major_Tom said:
It is because on a very fundamental level they truly did not understand what they were looking at.

For those who see authority as providing all the answers, that is a very hard pill to swallow. And there is no doubt that, on a very fundamental level, that simple fact produces a type of cognitive dissonance within an environment like JREF/ISF.

This thread, from the very first posts, is a perfect example of how this cognitive dissonance is manifested.
Click to expand...

That is a faulty analogy MT, I see no where in your work where you excluded newtons second law of motion, as indicated in the math, via the D'Alembert's principal, that's
What DBB wanted was proof, that another force was at play.

The picture is still blurred as far as models of the physics of the event.

Most likely because both sides of the argument are looking at only partial pieces
Never seeing the whole picture.
 
It seems clear in reading some of the comments on this thread that the early discussions produced a lot of wrong headed thinking... such as the impossibility of crush up... if I understand some of these quotes.

Ironically if one looks very carefully one can see what is taking place in the collapse of 1wtc... and infer with decent reliability the mechanisms responsible. What one can't explain with reliability is what was going on where you can't see... ie inside the tower in the period from plane strike to naked eye visible movement.

I find the discussions of the collapse phase almost trivial because it's in plain sight... and call it whatever acronym you want. There are questions to answer... such as would any very tall building be susceptible of the FORM / mechanism of collapse? Was there any aspect to the design which led to the FORM / mechanism of collapse?

The math related to floor destruction is really settled engineering.. Engineering books are filled with all manner of load tables for various assemblies and structural members.

What needs to be explained or speculated upon is how a partially compromised structure (upper section) lost its integrity and support and came crashing down on the bottom structure. "Heat" was the thing... HOW DID IT DO IT.

Hello Mr B and DBB et al.

Your turn
 
Major_Tom said:
It is because on a very fundamental level they truly did not understand what they were looking at.

For those who see authority as providing all the answers, that is a very hard pill to swallow. And there is no doubt that, on a very fundamental level, that simple fact produces a type of cognitive dissonance within an environment like JREF/ISF. ...
Click to expand...

You don't say it, but you insinuate, that specific members here, countable and nameable, "see authority as providing all the answers".
Can you estimate how many of those who have posted within this thread "see authority as providing all the answers"?
Even better, can you please name a few specific posters who "see authority as providing all the answers"? For example, do you think that I "see authority as providing all the answers"? A simple Yes or No would be appreciated - in fact is expected here.


Oh, and while we are at it - you are still dodging a very simple question from http://www.internationalskeptics.com/forums/showthread.php?postid=10906923#post10906923
Do you claim that I, Oystein, have expressed strong views of any kind over BV and/or BL?
Please do not forget about the emphasized word that was in the question from the very beginning, when you pen your answer of "Yes" or "No".​
 
Major_Tom said:
...
This thread, from the very first posts, is a perfect example of how this cognitive dissonance is manifested.
Click to expand...
Just like your book. Does this include NIST and Bazant, and the hundreds of other studies you don't like?
This is a result of not understanding models, science, physics, math and engineering. At least the book has a purpose; psychological technobabble conclusion...
In reality there is no scientific approach and, therefore, no technical history of the collapses at all. This is a verifiable statement.
Click to expand...
The conclusion, a lie.

When did you stop believing in CD with respect to your OOS model? When did you drop the gravity collapse was an illusion idea?

You can't answer why? But you do ask questions you can't answer, or comment on. A method used to avoid, why?

When you sent your "book" to a journal, what happened?
 
beachnut said:
More questions; where are the "book" answers? What do you think you are, a professor like paper chase? Your posts are evidence of a lack of understanding engineering models.
Is it true you still believe in CD? Or did you drop the fantasy of CD, and the nonsense the gravity collapse is an illusion? If you did drop the CD fantasy; why, when and what made you wake up to reality?


Did you comment on this yet?


Why can't 911 truth understand engineering models?
Click to expand...

When I took Physics 101 there were 30 in the class, in Physics 102 there were 15 and in 103 there were only 5, you are arguing with those 25 who didn't make it.
 
ozeco41 said:
[qimg]http://conleys.com.au/smilies/clap.gif[/qimg] Well said Sir!

As a newbie to this forum - so probably 2009 - I was confronted by a clear hierarchal arrangement with Ryan Mackey as king. (He seemed to have ascended to the throne as heir apparent to Gravy). There were several Princes.

Ryan had done a lot of great work - probably at the leading edge of "debunker" thinking at the time.. An admirable expenditure of effort.

I - the newcomer - dared to risk lèse majesté and politely corrected him on an error of engineering physics. And got slapped down for impertinence. I was right but let it pass not wanting to take on alpha dog at that time - if ever. Then as now my interest is in the technical facts - not "winning or losing" OR ranking of competitors. Ryan totally ignored the advice on physics.
Click to expand...

Link?

I see, you were the alpha dog in other situations and resented not being one here, explains a lot.
 
Status
Not open for further replies.

Back
Top Bottom