900 replies to this topic

[Q24]

booNyzarC, on 18 September 2012 - 01:04 AM, said:

Is this the kind of non-rudeness that you suggest we use for our interactions?

Yes... because I didn’t call your question pathetic, only despaired that you asked it and have little confidence you will understand the answer after having gone over the subject already.

booNyzarC, on 18 September 2012 - 01:04 AM, said:

I don't recall ever claiming, for example, that there was 'little to no intermediary structure.'  I am honestly at a loss for how you could reach that conclusion.

It’s your continual reference to “floors” and “pancaking” whilst ignoring my requests to clearly address and account for the core structures.

booNyzarC, on 18 September 2012 - 01:04 AM, said:

I will ask you again to substantiate this claimed 'loss of momentum witnessed in video footage and the seismic record.'  As for the rotation/displacement of the WTC1 antenna, I've already proven that the chunk of antenna that you once believed was still attached to the supposedly fully rotated roof was in fact not attached to anything at all when it emerged from the debris cloud.  Why you persist with this claim is truly baffling to me.

I can see the momentum loss by eye, though you are welcome to do some of that frame analysis on the collapse front at the North West corner at 0:22 in the WTC1 Hoboken video we have been viewing.  Compare the rate of collapse there to other periods and you will notice the reduced momentum in that second.  I’ve also noticed that a split second before 0:22 is where the large debris ejections begin coming from the towers – another sure sign that the lower block is now having increased success in resisting the upper block mass.  A further observation is that height of the surviving WTC1 core ‘spire’ matches the location where the reduced collapse rate occurs, further corroborating the upper block was broken at that point.  All in the same moment, the seismic record shows a reduced activity reading which I’ve already shown you and further indicating the loss of momentum to be correct.

Regarding the antena displacement, I’ve already explained to you  it does not need be attached at that point... how many times?... it’s the fact the antena is found so far outside of it’s own rotational arc that needs to be addressed.  What is so “baffling” to you?  One highly fitting solution is that rotation of the upper block carried it there, and no other answer has been forthcoming.  We have been over all this before.

booNyzarC, on 18 September 2012 - 01:04 AM, said:

You readily admit that halting the upper block in its tracks is an impossible task.  This is exactly what would have to happen for a gravity driven collapse to be stopped.  How can you possibly not realize this?

I have never said that the upper block didn't deteriorate throughout collapse.  I've always maintained that the upper block sustained significant damage throughout collapse and I've never recoiled in terror from that position.  Are you joking?  I think this may fall back to your confusion between the actual collapses, Bazant's limiting case, and my efforts at simplified models to illustrate key concepts.

Bazant's limiting case is not an effort to mimic the actual collapses.  Bazant's limiting case is an effort to provide a best case scenario for halting the upper block.  He states quite clearly that his case is not realistic and that the actual collapses did not follow the assumptions he intentionally placed in the paper.  Those assumptions he placed were for the benefit of building survival, despite what you may misunderstand about them.

It is impossible to stop an intact/rigid block in its tracks.  It is possible to gradually stop collapse of a broken block.  This is where we start having real problems  - how can you possibly not realise the difference between the two?  How can you possibly not realise that Bazant relies on the former?  How can you possibly not realise that a rigid/intact upper block is not a best case for halting the collapse?  How can you possibly not realise that assumptions such as an initial freefall drop that never existed in reality are not beneficial to the tower survival?  We have been over all this before.

booNyzarC, on 18 September 2012 - 01:04 AM, said:

Backtrack?  What are you on about Q24?  I haven't backtracked from anything, and you certainly haven't put my position in any kind of peril, severe or otherwise.

I’m referring to your backtracking from this (green text)...

http://www.unexplain...50#entry4273127

The quote you responded with only served to backup what I’d said.

With this approach you have shown - dragging up long ago addressed points and backtracking where the official theory is proven incorrect - at best I can use your comments to make a point, but there will never be a resolution between us.  That's why I'd still like to use the time I have to focus on discussion with LG for the moment.

[booNyzarC]

There is so much wrong with your post Q24, but I only have time to address a few of the points.  And yes, I realize that you were directing this to LG, but I just have to comment about some of this.

Q24, on 19 September 2012 - 07:51 PM, said:

The motion of the lowest affected story is not downward due to gravity but always due to the ‘greater than gravity’ momentum of the upper block.

If this is this your concept regarding the momentum of the upper block and gravity, it's no wonder that getting you to understand the rather simple mechanics of collapse has been so difficult.  What exactly is 'greater than gravity' about the momentum of the upper block?  The two aren't directly comparable.

This statement makes me think that you may envision that gravity imparts a specific and constant velocity on an object in free fall.  It doesn't.  It imparts acceleration, which is the change of velocity over time.

Momentum (p) is a measurement of an object in motion at a specific velocity (v), and consists of that velocity (v) times the mass (m) of that object.

p = mv

Gravity provides a constant rate of acceleration for objects which are falling.  This is at about 9.81 meters per second squared (9.81 m/s²).  Meaning that as the object falls, its velocity (v) increases over time.

When two objects collide, there is a resultant change in velocity for both objects, and this is due to momentum.  After a new momentum (and therefore a new velocity) is determined from that collision, any additional forces which would impart acceleration (i.e.  gravity) continue to work from that point forward and the speed of the object(s) continue to increase in velocity over time unless the object which was falling is completely halted.

Q24, on 19 September 2012 - 07:51 PM, said:

Sorry, I thought you were up to speed with this: -

“I think he [Bazant] is a criminal. You can quote me because I’ve already said that on my web site.  This guy is a Lysenko-type scientist.  He’s presenting a false theory for whatever purpose.  I don’t know why he does it.”

~Anders Björkman, European structural engineer

http://norcaltruth.o...-zdenek-bazant/

"As will become apparent below, the rules at JEM that govern other authors do not apply to Dr. Bazant."

~James Gourley, U.S. attorney

http://911blogger.com/node/18196

Is this the same Anders Björkman that claims the lower part of the tower would survive even if you dropped the upper block from two miles high?

What a stellar reference you have there...  

Q24, on 19 September 2012 - 07:51 PM, said:

I would still like an answer to the question: how is it that Bazant can achieve what no computer based physics simulation can?

Here's a thought... Maybe because Bazant wasn't trying to achieve a simulation?

Q24, on 19 September 2012 - 07:51 PM, said:

as soon as you admit the upper block deteriorates throughout the collapse that the official theory goes in the bin.

No it doesn't.  What a ridiculous statement.

[booNyzarC]

Q24, on 17 September 2012 - 10:53 PM, said:

Ohhh you make me despair sometimes – you know how because we have been over it.  The vastly different models alter location of the force application: -




I’m hopeful, rather than confident, that you see difference between the first and second images...

If we talk about “floors” with little to no intermediary structure (because each lower story in particular is assumed completely and immediately destroyed upon contact with the upper mass), then the sequence of freefall drops is going to create forces applied from the lowermost impacted story.  This is what you propose.

If we accept the core structure (which consisted of continuous columns and open elevator shafts and stairwells, i.e. limited “floors”) then the opportunity for freefall, where the upper block in isolation builds a ‘debris shield’ and suffers reduced force at subsequent impacts, is removed – the intermediary structure throughout collapse providing as much of a ‘shield’ to the lower block as the upper block and resulting in overall equal and opposite damage to the blocks.  This is what I propose.

In reality the structures and collapses were more like the second description above – this supported by the known construction, computer physics models of continuous structures and evidence of the collapses, for instance, the 60 story lower core column ‘spire’ which penetrated right through the upper block, the loss of momentum witnessed in video footage and the seismic record, the continued rotation/displacement of the WTC1 antenna.

You depict the columns in your image as though they are completely separated from the rest of the structure.  I suspect that this is just a simplification in order to give the core distinction from the floors of each building story.  I'm sure that you are aware that the floor trusses were attached to the core columns, and the core columns to each other with horizontal cross beams.  Because of this, it is possible to have localized buckling on each story as described by Swanny back in post 248.

At the same time, yes the core columns are a continuous structure, but so are the columns comprising the perimeter tube.  Meaning that they are stacked on top of each other and bolted/welded together to form a continuous vertical support, tied together by horizontal cross members.  I believe that it is for this reason that Bazant presents his case the way that he does, not to try to mimic the actual collapse mechanisms, but to create a scenario in which the structural elements most resistant to collapse are tested against the falling mass of the upper block using a simplified format.

The animation below is intended to help visualize what Bazant means when he introduces his limiting case.

For our purpose, we may assume that all the impact forces go into the columns and are distributed among them equally. Unlikely though such a distribution may be, it is nevertheless the most optimistic hypothesis to make because the resistance of the building to the impact is, for such a distribution, the highest. If the building is found to fail under a uniform distribution of the impact forces, it would fail under any other distribution. (source Bazant)

What I intend to convey with this is a rudimentary visualization.  Please note that even though my depiction of column deformation is relatively uniform, it need not be for consistency with Bazant's papers.

• It begins with a near free fall drop of the upper block through the initially failed region between the 98th and 99th floors, starting with a downward velocity of zero.
  
• Then upon each collision we see the collapsing columns impact directly with the columns in the structure below.
  
• This collision is assumed to be inelastic, meaning that the upper block and the top story of the lower block 'stick together' when they hit, and following the conservation of momentum a new velocity is determined for the falling mass which is slower than the velocity of the upper block immediately prior to impact, but faster than the velocity of zero when collapse initiated.
  
• The impacted columns buckle until their yield strength is surpassed, which would carry with it a barely perceptible 'jolt.'
  
• The columns then fail and inelastically deform with plastic hinges; which maximizes the dissipation of energy imparted by the falling mass of the upper block.
  
• As the columns fold in on themselves from the crushing force of the upper block, their load bearing capacity diminishes rapidly and the entire portion above the lowest part of the currently crushing story continues to accelerate downward due to gravity until it impacts with the next story. (Note: This is not necessarily at free fall speed per se, but it is accelerating and that acceleration is imparted by gravity even during deformation.)
  
• The rest of the collapse consists of repeating steps 2 through 6 over and over.

Again, this isn't what actually happened when the towers collapsed, but as Bazant stated -- when impact forces are distributed equally among the columns, it offers the highest resistance for survival of the building.

Please notice that this animation also sort of shows what I've referred to as 'pancake-like elements,' though in the actual collapses these elements spanned multiple stories due to the tilting of the upper block (not depicted in this animation obviously), and the 'pancake-like elements' were localized as a result, though continuously projecting along the tilted edge of the collapse front itself.


I know that you have complaints regarding 1. the assumption of a free fall drop, 2. the assumed column to column impact, 3. the fact that we don't see a jolt in the footage during early stages of collapse as is predicted by Bazant's limiting case, and 4. the survival of the upper block throughout collapse within the model.  So let's deal with those complaints.


1. The assumption of a free fall drop.

You contend that this assumption does not favor building survival and didn't happen in the actual collapse.  You are correct on both counts and I agree with you, but does this have a significant impact on Bazant's limiting case?  No, it really doesn't.

Bazant defends the impact of this simplifying assumption as follows:

Didn’t Plastic Deformations "Cushion" the Vertical Impact?

It has been suggested that the inelastic deformations of columns, analyzed in Appendix II of Bazant and Zhou (2002), might have significantly "cushioned" the initial descent of the upper part, making it almost static. However, this is impossible because, for gravity loading, a softening of the load-deflection diagram [Fig. 5 in Bazant and Zhou (2002)] always causes instability that precludes static response (Bazant and Cedolin 1991, Chapters 10 and 13). The downward acceleration of the upper part is ü = N[P⁰₁=P₁(u)]/m where N = number of buckling columns in the floor and, necessarily, P⁰₁=mg/N. This represents a differential equation for u as a function of time t. Its integration shows that the time that the upper part takes to fall through the height of one story is, for cold columns, only about 6% longer than the duration of a free fall from that height, which is 0.87 s. For hot columns, the difference is of course much less than 6%. So there is hardly any "cushioning." It is essentially a free fall. (source Bazant)

What he is describing here is that once the yield strength of the columns are breached and they begin to deform with plastic hinges they are no longer capable of bearing the load on top of them and this is an extremely rapid process.  It isn't a slow bending, hence the usage of the word buckling which in itself is nearly instantaneous.  Essentially it is like a series of kinks that form in the columns and because they can no longer hold the upper mass in place, the upper mass falls through them very rapidly (because of gravity).  It would be like taking your car and gently setting it on the coffee table in your living room.  It would collapse at virtually free fall speed.  The same is true for the initial failing story (and even the first several stories) because the steel had been heated by fires, significantly reducing their strength, and a great number of columns had already been heavily damaged and/or severed by the impacts of the planes.

So even though your complaints are technically correct, the simplifying assumption of free fall is soundly reasoned and would have virtually no perceptible change on the end result.


2. The assumed column to column impact.

If I'm not mistaken your complaint here is twofold.  First, it clearly didn't happen in the actual collapses, and second, you are of the opinion that this assumption is in favor of collapse instead of being in favor of building survival.

The first complaint is easy to address.  It wasn't intended to mimic the exact collapses, so honestly this complaint has no merit and no basis.

The second complaint is likewise without merit because the columns cannot stand on their own.  The structural integrity of the building requires the stability provided by the floor trusses connected on one end to the core columns and on the other end to the columns comprising the perimeter tube.  The buildings need all of these elements intact in order to remain standing.  If the falling mass completely misses all of the vertical elements altogether, the floor trusses have absolutely no hope of halting the downward motion and a collapse similar to the early 'pancake theory' would inevitably ensue.

The only hope for building survival is halting the upper mass, and the strongest and most capable elements to achieve that are the columns.  No examples of balls falling on trees is going to change this simple reality.

3. The fact that we don't see a jolt in the footage during early stages of collapse as is predicted by Bazant's limiting case.

The actual collapses didn't have column to column impacts and the columns weren't universally buckling throughout.  In fact, the mechanics of the actual collapses were taking place in a variety of ways including buckling and fracturing, and over a wide area spanning multiple floors.  There is no perceptible jolt because instead of one big impact, as would happen if the actual collapses occurred in a perfectly uniform fashion similar to Bazant's limiting case, there are thousands of smaller impacts taking place over a very short period of time.

4. The survival of the upper block throughout collapse within the model.

As mentioned above when discussing your first complaint, the initial floors that failed were heavily damaged and weakened by fires.  Even though neither NIST or Bazant use these words, the upper block would have cut through the first 4 or 5 floors like a cold knife slicing warm butter.  By the time it had collapsed through these floors it would have accumulated the mass of those floors which would provide a shield against impact forces delivered during subsequent collisions.  Even if we assumed that the columns between floors 99 and 100 buckled and deformed upon the initial impact, every impact following that takes place on the bottom side of the compressed central mass because that's the direction gravity accelerates the unsupported upper block.

This is not in defiance of Newton's third law, it is in complete congruence with it.


If I have missed any of your complaints, please let me know and I'll try to address them.


And please keep in mind that the content of this post is primarily regarding Bazant's limiting case, not the actual collapses, which are distinct.

[booNyzarC]

Q24, on 19 September 2012 - 08:19 PM, said:

Yes... because I didn’t call your question pathetic, only despaired that you asked it and have little confidence you will understand the answer after having gone over the subject already.

And you still haven't answered that question by the way.  My question was "How does the application of Newton's third law change exactly?"

Do you want to know why I asked that question?  I asked it because you can't change the application of Newton's third law.  There is only one application for it.  If you try to change that application you are in error.

Q24, on 19 September 2012 - 08:19 PM, said:

It’s your continual reference to “floors” and “pancaking” whilst ignoring my requests to clearly address and account for the core structures.

Hopefully my post 333 adequately reconciles this confusion you have.

Q24, on 19 September 2012 - 08:19 PM, said:

I can see the momentum loss by eye, though you are welcome to do some of that frame analysis on the collapse front at the North West corner at 0:22 in the WTC1 Hoboken video we have been viewing.  Compare the rate of collapse there to other periods and you will notice the reduced momentum in that second.  I’ve also noticed that a split second before 0:22 is where the large debris ejections begin coming from the towers – another sure sign that the lower block is now having increased success in resisting the upper block mass.  A further observation is that height of the surviving WTC1 core ‘spire’ matches the location where the reduced collapse rate occurs, further corroborating the upper block was broken at that point.  All in the same moment, the seismic record shows a reduced activity reading which I’ve already shown you and further indicating the loss of momentum to be correct.

So I guess you simply refuse to substantiate this claim?  Telling me that you can supposedly see it isn't substantiation.  I've already refuted your initial attempt at substantiation back in post 256 and post 263, but you have yet to defend your claim.  Repeating the original claim again isn't defending it and isn't substantiating it.

I suggest you perform an analysis of the video (or any other video with a closer point of view) in your attempt to substantiate it.  I'll await your diligent work, and until then I'll assume that you are simply mistaken because my analysis has already shown that your claim is incorrect.

Q24, on 19 September 2012 - 08:19 PM, said:

Regarding the antena displacement, I’ve already explained to you  it does not need be attached at that point... how many times?... it’s the fact the antena is found so far outside of it’s own rotational arc that needs to be addressed.  What is so “baffling” to you?  One highly fitting solution is that rotation of the upper block carried it there, and no other answer has been forthcoming.  We have been over all this before.

You present one way for the antenna chunk to arrive where it did and unilaterally declare that this must be the only way it could have got there.  It's as if you have blinders on and refuse to consider any other possibility because this is your preferred answer.

First of all, the upper block could not have possibly rotated fully outside of the footprint of the building.  It is impossible.

Bazant describes why on pages 4 and 5 in Appendix II of his initial paper.  It is titled Why Didn't the Upper Part Pivot About Its Base?  Rather than having me quote it, perhaps you should go read it.  This in itself proves that your "one and only possible conclusion" is false and that you need to consider other possibilities.  Other explanations like the fact that the antenna probably broke apart during the collapse because of a combination of violent whipping back and forth and the snapping of the guy wires.  Then the chunk we see falling was either whipped outside the building footprint by the flailing mast of the antenna or it simply bounced off the roof.

Your refusal to even entertain such simple explanations as these is what is baffling to me, and you still contend that you've been given no other possible reasons.  I'm at a loss for how to respond beyond that.

Q24, on 19 September 2012 - 08:19 PM, said:

It is impossible to stop an intact/rigid block in its tracks.  

I agree completely, and this is EXACTLY what the upper block was once the collapse initiated.  It was a fully intact and structurally sound chunk of the building.  One huge massive block.  How massive was it?  It was 30972.62 metric tonnes worth of massive, structurally sound, and intact chunk of building... falling.

Absolutely nothing in the lower structure could possibly stop that.  Ever.

Q24, on 19 September 2012 - 08:19 PM, said:

It is possible to gradually stop collapse of a broken block.  This is where we start having real problems  - how can you possibly not realise the difference between the two?  How can you possibly not realise that Bazant relies on the former?

It is NOT possible to gradually stop the collapse of a broken block with that much mass all falling simultaneously.  Even if the columns in the lower block manage to gradually break the upper block into pieces, those pieces are still falling and the columns of the upper block would likewise be breaking apart the lower block to create even more falling mass.  Bazant doesn't rely on an intact block, it starts as an intact block and within the limiting case it remains so because of the column on column impacts, subsequent buckling and deformation, and the weakened elements of the initially impacted floors due to impact damage and fires.

Q24, on 19 September 2012 - 08:19 PM, said:

How can you possibly not realise that a rigid/intact upper block is not a best case for halting the collapse?  

An intact and rigid upper block is an observable reality of the actual collapses at the point of initiation.  The upper block starts off fully intact and breaking it apart would be a gradual process during which the lower block also sustains damage and breaks apart due to Newton's third law.  As the upper block is being broken apart, it continues to fall, and as the lower block is being broken apart, additional falling mass is added to the initial 30972.62 metric tonnes.

Q24, on 19 September 2012 - 08:19 PM, said:

How can you possibly not realise that assumptions such as an initial freefall drop that never existed in reality are not beneficial to the tower survival?  We have been over all this before.

I believe that I've addressed this in post 333.

Q24, on 19 September 2012 - 08:19 PM, said:

I’m referring to your backtracking from this (green text)...

http://www.unexplain...50#entry4273127

The quote you responded with only served to backup what I’d said.

I've already responded to this baseless accusation in post 163.  I've never backtracked from my position on this, I've only described it in different terms in an effort to clarify what is happening because you seem incapable of grasping the concepts.  That is what people do when trying to explain something and the receiving party just isn't "getting it."  They try to explain the same thing in a different way in the hopes that the receiving party might more successfully connect with the core points.  This often starts with a phrase like, "Okay, well let me put it this way instead."  Are you familiar with this practice?

Q24, on 19 September 2012 - 08:19 PM, said:

With this approach you have shown - dragging up long ago addressed points and backtracking where the official theory is proven incorrect - at best I can use your comments to make a point, but there will never be a resolution between us.  That's why I'd still like to use the time I have to focus on discussion with LG for the moment.

If there is never a resolution between us it won't be for lack of effort on my part.  Feel free to continue discussion with LG, but I intend to continue commenting all the same.

I really do hope that you can at least understand what I've been describing, because so far a great deal of your arguments have been about things that I'm not even intending to convey and that I'm frankly surprised you've somehow concluded from my actual statements.  If there is any confusion about any point I've tried to make, please ask and I'll try to clarify by putting it another way.  

Cheers.

[W Tell]

(Sigh) Here we are again, debating the physics of this. And getting nowhere.

I've already put forward that the buildings needed to fall. Can I ask this quick question... Did the terrorists understand physics enough to hit the buildings as they did and bring them down in a timely manner? As far as I know, the whole conversation on these collapses have only happened after that day. As if no one saw it coming.

But I do remember an archetect talking about how well these buildings could sustain a hit, before the fact.

So did the terrorists know the buildings would fall using physics (that seems to be the area in most contention right now) or did they get lucky. Cause result wise, they definatly improved from their 93 effort.

[Liquid Gardens]

W Tell, on 20 September 2012 - 12:10 AM, said:

(Sigh) Here we are again, debating the physics of this. And getting nowhere.

I've already put forward that the buildings needed to fall. Can I ask this quick question... Did the terrorists understand physics enough to hit the buildings as they did and bring them down in a timely manner? As far as I know, the whole conversation on these collapses have only happened after that day. As if no one saw it coming.

But I do remember an archetect talking about how well these buildings could sustain a hit, before the fact.

So did the terrorists know the buildings would fall using physics (that seems to be the area in most contention right now) or did they get lucky. Cause result wise, they definatly improved from their 93 effort.

We should be able to get somewhere though, physics is objective and has defined rules.  If you can't get anywhere with physics, I'm not sure what hope there is for progress on other more subjective topics.  I think the current area of contention is the feasibility of the towers collapsing from the damage and fire alone, and the evidence for a demolition.

I'm not sure that the terrorists knew that their attacks were going to cause the total collapses that it did. I think the need for a collapse, so far that I've heard of, is from the alleged American/Zionist conspirators.    Not sure on that though, and I guess I'm not sure by 'terrorists' you only mean the AlQaeda guys, or if you're also including the other proposed conspirators. Even if the buildings hadn't collapsed, it still would have been the most damaging terrorist attack in history that I'm aware of, I think the AQ terrorists would have settled for that possibility gladly.

[booNyzarC]

Q24, on 19 September 2012 - 07:51 PM, said:

I think simple viewing of the tower collapse footage, where Gage commentates on destruction of the upper block, tells us the correct answer far more effectively than any of our arguing over it – there’s no disputing reality.

The problem with Gage's interpretation is that he erroneously includes the upper portion of the lower block as part of the upper block when collapse initiates.

His lower red line is around what floor?  The 90th or so?  I'm not sure, I'd have to look very closely and count, but it is most certainly not where collapse initiated.

The actual collapse initiation was at about the 98th story, as we can clearly see here:




So his whole claim about the upper block being destroyed 4 seconds into collapse is complete nonsense and based on either intentionally misleading or misinterpreted evidence.  Of course the floors immediately below the 98th are destroyed in short order, they were damaged by the impact of the plane and ravaged by the subsequent fires.  This is the 'cutting through butter' reference that I have been talking about.

It isn't the upper block being destroyed, it is the top layers of the lower block being destroyed.

Surely you can see this Q24?

[Q24]

booNyzarC, on 19 September 2012 - 08:23 PM, said:

What exactly is 'greater than gravity' about the momentum of the upper block?

Ok that wasn’t the clearest description I gave.  Though I would really have expected you to get it in context of the rest of the paragraph.  All I was saying is that existing velocity of the upper block is greater than gravity can accelerate any broken structure at the collapse front... therefore momentum of the upper block is always the driving force of the collapse... and the upper block must suffer continued damage as a result.  We’ve been over it all before.

booNyzarC, on 19 September 2012 - 08:23 PM, said:

Is this the same Anders Björkman that claims the lower part of the tower would survive even if you dropped the upper block from two miles high?

That is an interesting question.  In that scenario there’s going to be a lot more momentum than ever existed on 9/11.  There is also going to be less time for columns to bend and connections to sheer, meaning greater force expended in the impact and increased damage to any given story – due to the equal and opposite forces of Newton’s third law, there’s going to be very little left intact of the upper block in very short order.  Bjorkman’s theory has potential.

No defence to the comments of James Gourley?

booNyzarC, on 19 September 2012 - 08:23 PM, said:

Here's a thought... Maybe because Bazant wasn't trying to achieve a simulation?

That is no sort of point at all.  Did you not realise that a simulation should be able to validate or disprove a theory?  Here’s a thought as to why every vaguely accurate simulation available disproves Bazant’s theory... because a computer based physics model cannot bend the rules as a back of an envelope theory can.

booNyzarC, on 19 September 2012 - 08:23 PM, said:

No it doesn't.  What a ridiculous statement.

That was rude  

So what part of...

"An important hypothesis implied in this analysis is that the impacting upper part, many floors in height, is so stiff that it does not bend nor shear on vertical planes, and that the distribution of column displacements across the tower is almost linear, like for a rigid body."

... and its implications don’t you understand?

It’s simple.  If the upper block is not stiff, does bend and/or sheer, and is not rigid, come any point during the collapse, then Bazant’s theory (the official theory) as it stands no longer explains the progression.

I’m sorry to say that I got bored reading through the same repetitive and easily refuted points of your next posts so won’t comment.  Except for the animation.  That’s most interesting.  It is inaccurate in ways so telling – clearly put together by someone with a bias and/or who doesn’t understand either the building construction or collapse or even the official theory - but interesting nonetheless.  Did you make that animation booNy, or simply endorse it?

[Q24]

Liquid Gardens, on 20 September 2012 - 12:22 AM, said:

I'm not sure that the terrorists knew that their attacks were going to cause the total collapses that it did.

"We calculated the number of casualties from the enemy, who would be killed based on the position of the tower. We calculated that the floors that would be hit would be three or four floors. I was the most optimistic of them all. (...Inaudible...) due to my experience in this field, I was thinking that the fire from the gas in the plane would melt the iron structure of the building and collapse the area where the plane hit and all the floors above it only. This is all that we had hoped for."

~Osama bin Laden, 2001

It seems that even the alleged 'mastermind' endorsed my argument.

Stick around W Tell, it's a breath of fresh air to have a different perspective and direction on the discussion.

[booNyzarC]

Q24, on 20 September 2012 - 12:56 AM, said:

Ok that wasn’t the clearest description I gave.  Though I would really have expected you to get it in context of the rest of the paragraph.  All I was saying is that existing velocity of the upper block is greater than gravity can accelerate any broken structure at the collapse front... therefore momentum of the upper block is always the driving force of the collapse... and the upper block must suffer continued damage as a result.  We’ve been over it all before.

We have been over it before and you still don't get it.  After the momentum of the upper block impels the crushed portion at the top of the lower block to a specific velocity, gravity continues to accelerate both from there as collapse continues.

Q24, on 20 September 2012 - 12:56 AM, said:

That is an interesting question.  In that scenario there’s going to be a lot more momentum than ever existed on 9/11.  There is also going to be less time for columns to bend and connections to sheer, meaning greater force expended in the impact and increased damage to any given story – due to the equal and opposite forces of Newton’s third law, there’s going to be very little left intact of the upper block in very short order.  Bjorkman’s theory has potential.

Bjorkman's theory has the potential to get him laughed out of any structural engineering firm in the world.  If he still has a job, I'd be shocked and appalled at his employers.

Q24, on 20 September 2012 - 12:56 AM, said:

No defence to the comments of James Gourley?

I'll have to look into this I suppose.  I haven't looked at James Gourley yet, but am I correct that he's an...  attorney?  Well then, I guess we should expect some convincing structural engineering and physics points from him eh?  I'll have to give a full evaluation a rain check if you don't mind.

Q24, on 20 September 2012 - 12:56 AM, said:

That is no sort of point at all.  Did you not realise that a simulation should be able to validate or disprove a theory?  Here’s a thought as to why every vaguely accurate simulation available disproves Bazant’s theory... because a computer based physics model cannot bend the rules as a back of an envelope theory can.

It is a perfectly valid point.  Bazant wasn't trying to mimic the actual collapse sequences, he was making assumptions in favor of building survival (with the exception of assumed free fall of the upper block of course).  No simulation is going to depict column on column impact and fully plastic buckling of the columns throughout collapse because it is blatantly obvious that these things did not happen; hence why Bazant wasn't trying to make a simulation.

Q24, on 20 September 2012 - 12:56 AM, said:

That was rude  

Funny.  

Q24, on 20 September 2012 - 12:56 AM, said:

So what part of...

"An important hypothesis implied in this analysis is that the impacting upper part, many floors in height, is so stiff that it does not bend nor shear on vertical planes, and that the distribution of column displacements across the tower is almost linear, like for a rigid body."

... and its implications don’t you understand?

It’s simple.  If the upper block is not stiff, does bend and/or sheer, and is not rigid, come any point during the collapse, then Bazant’s theory (the official theory) as it stands no longer explains the progression.

Limiting case.  Not reality.  Limiting case.  Not reality.

I swear, sometimes I just want to shake you Q24.  You are being obstinately obtuse in making the distinction between reality and Bazant's limiting case.

Q24, on 20 September 2012 - 12:56 AM, said:

I’m sorry to say that I got bored reading through the same repetitive and easily refuted points of your next posts so won’t comment.  

Easily refuted?  Oh really?  I guess that's why your response is a 'no comment.'  It couldn't possibly be because my last few posts completely destroy your entire position in this debate could it?  Because they most certainly do.

Tuck tail and run.  Avoid avoid avoid.  Great game plan Q24.

Q24, on 20 September 2012 - 12:56 AM, said:

Except for the animation.  That’s most interesting.  It is inaccurate in ways so telling – clearly put together by someone with a bias and/or who doesn’t understand either the building construction or collapse or even the official theory - but interesting nonetheless.  Did you make that animation booNy, or simply endorse it?

I made the animation and I made it to hopefully help illustrate Bazant's limiting case.  Again, it isn't representative of the actual collapse.  Which is clearly depicted on the image itself in plain text, intentionally, because I suspected that you would try to pull some kind of nonsensical BS about it.

But please do tell.  What is so telling about it's inaccuracy?  What does it indicate in terms of ignorance regarding building construction, collapse, or 'the official theory?'

I'm sincerely curious because I'm actually rather proud of that rudimentary animation and the explanations I provided which were intended to explain and clarify the visual.

Should I have said "there are more than 6 core columns?"  It seemed a reasonable simplification considering that your own image consisted of 6 core columns...  or was it 8?  I'm not sure whether you intended the heavier lines on either side of your 6 core columns to also be columns or if they were just the separation point for the horizontal floor depiction in your picture.  At any rate, I'm not creating an animation with 47 core columns with the tools I have available.  Perhaps if I had some decent CAD software I'd consider it.

[Liquid Gardens]

Quote

Bazant’s theory (the official theory)

Wait, I thought Bazant's theory was intentionally not supposed to be represent the actual collapse, how is it the 'official theory'?  I thought the NIST report was the 'official theory' to some extent, that's not quite the same as Bazant, right?  Sorry, just trying to keep my models straight.

[Liquid Gardens]

Boony, my understanding of the point of 'limiting case' is that it is kind of a best case scenario?  If the building cannot withstand this scenario than it can't withstand almost any.  If I'm understanding Q right, wouldn't it be an even more limiting case then if we hypothesized that the upper block is not rigid and is shedding mass to some extent, that would be more of a best case scenario for the lower block?  I think I understand how column on column impacts do favor the lower block survival, but not then a non-damaged upper block.  I'm not saying that the upper block was damaged enough to change anything, Q has largely just insisted there's deterioration with no adjective but of course the key question is 'how much' which is a complicated one, but I'm just trying to translate Q's point here if I'm understanding it correctly.

[booNyzarC]

Liquid Gardens, on 20 September 2012 - 01:26 AM, said:

Wait, I thought Bazant's theory was intentionally not supposed to be represent the actual collapse, how is it the 'official theory'?  I thought the NIST report was the 'official theory' to some extent, that's not quite the same as Bazant, right?  Sorry, just trying to keep my models straight.

Yes and no.  Bazant's limiting case is representative of the inevitability of global collapse under the best of conditions.  There is really only one assumption in Bazant's limiting case that isn't in favor of building survival, and that is the initial drop of the upper block at free fall speed through the initially failed story.  As explained in my post 333, the implications of this are negligible and the end result would still be the same even if free fall wasn't assumed, but free fall at initiation simplifies the overall scenario which is the predominant reason that Bazant included the assumption in the first place.

NIST on the other hand was completely, totally, and entirely focused on collapse initiation.  As soon as downward motion began (i.e. falling) they were done.  They didn't attempt to model the entire collapse sequence because Bazant's limiting cause proves that even under the best scenario, global collapse will commence once it is initiated.

So the two combined represent 'the official theory,' though after all of the study I've invested in this subject I'm inclined to agree that NIST may not have nailed collapse initiation with as much accuracy as I'd like.  Personally, I think that creep induced by the localized and concentrated damage of the plane impacts played a much larger role than the sagging floor trusses, but both contributed to the actual event without a doubt.

As for reference by the 9/11 Truth Movement to "the official theory of collapse" they are essentially referring to any idea which doesn't involve controlled demolitions.  It is ambiguous and all inclusive from what I've seen.  My way or the highway.  If you don't buy the controlled demolition claims, you're an "official theory" adherent.  This is a lot like BR's continuous parroting of "I don't know the real story, but the official one is definitely wrong!"

Liquid Gardens, on 20 September 2012 - 01:36 AM, said:

Boony, my understanding of the point of 'limiting case' is that it is kind of a best case scenario?  If the building cannot withstand this scenario than it can't withstand almost any.  If I'm understanding Q right, wouldn't it be an even more limiting case then if we hypothesized that the upper block is not rigid and is shedding mass to some extent, that would be more of a best case scenario for the lower block?  I think I understand how column on column impacts do favor the lower block survival, but not then a non-damaged upper block.  I'm not saying that the upper block was damaged enough to change anything, Q has largely just insisted there's deterioration with no adjective but of course the key question is 'how much' which is a complicated one, but I'm just trying to translate Q's point here if I'm understanding it correctly.

Yes, that is the intention of the limiting case.  If the building can't survive under the best of conditions, it will fail under any conditions.

You raise a valid point about the shedding of mass during collapse.  This certainly did happen during collapse as is clearly evident in all of the footage, and it did indeed shed tons of mass.  From a perspective of percentages though, how much was shed?  Was it 1%?  5%?  10%?  20%?  all the way up to 50%?  I don't know exactly how much was shed, but clearly it wasn't, and couldn't have been, as much as 50%.  25%?  Unlikely when you consider the geometrical area involved.  These buildings had huge footprints and only a certain percentage of the materials around the edges of the buildings could be expelled outward at the collapse zones.

How much would this impact the resulting collapse inevitability?  It wouldn't have a significant impact with such massive buildings.  The ejecta does serve to dissipate some of the energy imparted by the descending upper mass, but it isn't enough to significantly contribute to collapse cessation.  The vast majority of the crushed stories was prevented from being ejected due to the huge surface area of the collapse front(s), and therefore contributed to the descending mass of the upper block.

Hope that helps to clarify a bit.

[Liquid Gardens]

Quote

Hope that helps to clarify a bit.

It does, thanks.  It's my understanding that the floors could only hold about 6 stories being applied suddenly, so even with some mass ejection there's still a lot of mass left to withstand. Plus the collapsed floors adding mass, but I think that is being disputed.

[W Tell]

Liquid Gardens, on 20 September 2012 - 12:22 AM, said:

We should be able to get somewhere though, physics is objective and has defined rules.  If you can't get anywhere with physics, I'm not sure what hope there is for progress on other more subjective topics.  I think the current area of contention is the feasibility of the towers collapsing from the damage and fire alone, and the evidence for a demolition.

I'm not sure that the terrorists knew that their attacks were going to cause the total collapses that it did. I think the need for a collapse, so far that I've heard of, is from the alleged American/Zionist conspirators. Not sure on that though, and I guess I'm not sure by 'terrorists' you only mean the AlQaeda guys, or if you're also including the other proposed conspirators. Even if the buildings hadn't collapsed, it still would have been the most damaging terrorist attack in history that I'm aware of, I think the AQ terrorists would have settled for that possibility gladly.

Not quite what I was going for. Here's what I'm getting at. We have spent the last eleven years arguing about how these buildings came down. In all honosty the pro collapse people have lost this argument all these years to the point we get a blender effect and NIST pushing their models to the extreme.

We've had eleven years to justify these buildings falling as they did, it hasn't happened. I know it would if the truthers would just shut up. But they don't. We are left now with an official story so convluted that Isaacs laws mean nothing. I won't even bring up Bazant, who's not supposed to be talking about this collapse, but he is...

With all of this in mind, did the terrorists just give it another flying **** (excuse my launguge) and hit the buildings differently than in 93? Or did they know that with a major attempt like this, that if they had the balls and the audasity to follow through, that their plan would come to fruition? No one ever talks about how much the terrorists knew, ever.

But here we are eleven years later. The CT side has not changed. The OC has had to remodel the collapses over and over again just to make it work.

If we screw around with these facts so long after the event, of a collapse, after the impact, would they have been confident to pull the event of in the first place? (please don't tell me they would because they were religious zealots)