Merged Applicability of Bazant's model to the real world

[ProBonoShill]

I think most rational people would call your reply here incoherent. You seem to use that word loosely, much like your silly attempts at explaining the lack of deceleration of the upper section of WTC 1 as being possible in a natural collapse.

I'm a rational person and his reply made complete sense. He explained it well enough that a layperson such as myself can understand it, why you an engineer cannot is beyond me. Are you really an engineer?

It is actually a joke that anyone technical who has looked into the technical aspects of Sept. 11, 2001, and is even a little bit aware of politics, can come away with any conclusion other than it was a shock and awe ruse to get the people of the U.S. to support the use of their military for pre-planned illicit oil wars.

Do you have a theory about what happened on 9/11?

Care to share?

What benefits were gained in these "illicit oil wars" ? Evidence, got any?

On top of the evidence for controlled demolition, there is so much evidence for motive by insiders, with things like the PNAC manifesto, Dick Cheney's secret national energy policy meetings, and the Bush administration's lies about WMD in Iraq etc. that one has to make a concerted effort to ignore it and keep believing it was all fortuitously caused by evil terrorists from an area that these people wanted some control over.

Ahhhh the chronic truther dilemma:

How did people who weren't competent enough to plant a few WND in Iraq or disguise their plans for mass murder, manage to pull off an operation involving thousands of people without leaving any evidence or ever being implicated.

Will you be the first person to solve the dilemma Tony?

 

[GlennB]

The reason why the verinage demolition has a noticeable impact and the WTC didn't is rather simple. An offset of just a couple of inches causes a dramatic difference between an open-steel shape (such as an HSS in the WTC) and a concrete column. Observe:

[URL]http://www.internationalskeptics.com/forums/imagehosting/thum_163294ca33ea7e99ac.jpg[/URL]

As seen, the impact area of the concrete is still most of the original area. The column will probably fail in compression buckling.

The steel impact is about 1% of the original area, however. What does this mean? It means that about 1% of the steel shape from the upper block and 1% of of that from the lower block impact. The entirety of the force must be transmitted through this location. The local areas do not have enough capacity to develop 3mg, as Tony Szamboti likes to claim. Instead the steel will cut through each other. An expression "like a hot knife through butter" might apply here, but I think a demonstration of it is in order:

[URL]http://www.internationalskeptics.com/forums/imagehosting/thum_163294ca33f522e512.jpg[/URL]

Apologies to Howard Taylor.

Very illuminating, thank you. So whether they meet as mangled scrap or pristine ends slightly offset (in a Szambotian fantasy impact) the result is the same.

But my French is weak. Is his duck "on fire" on "in the oven" ?

 

[grmcdorman]

From my high-school french:
"Mon canard est en feu" = My duck is on fire
On the box, "Beurre du Quebec" = Quebec butter. Can't read the text on the other side of the box, appears to be "product of French [illegible]" (lit. francophone, i.e. French culture).
"Pas de probleme" = No problem.

No oven to be seen, that I can tell.

 

[GlennB]

From my high-school french:
"Mon canard est en feu" = My duck is on fire

No oven to be seen, that I can tell.

Right, that was my impression. So why would he want to chainsaw a box of butter because his duck is on fire? So soothe its burns? If his duck was "in the oven" I can see a pressing need for butter, to put on the roasting duck. Est-ce que je manque le point ?

 

[Newtons Bit]

Eeehn, he's a French Quebecer. He's not supposed to make sense.

 

[ozeco41]

Meanwhile, back on the topic, we seem to have reached the stage where:

• Bazant and Zhou made very conservative assumptions in their paper - one being that there was axial contact between top portion and bottom portion of columns at the start of the "global collapse";
• That assumption showed that there was sufficient energy for "global collapse" even in that most conservative scenario;
• MacQueen and Szamboti took that extreme conservative assumption as the premise for their "Missing Jolt" paper;
• In the actual collapse of the Twin Towers there was not (much if any) axial contact between column parts;
• Therefore Bazant and Zhou is not applicable to support "Missing Jolt" or any other analysis which relies on the presumption of full axial contact to transfer near design loads;
• and, drifting slightly from topic, that inapplicability is one of the fundamental errors in "Missing Jolt".

Is that the correct status of the topic?

Does anyone wish to pursue the topic into further detail? Or is that wishful thinking?

 

[ergo]

[*] In the actual collapse of the Twin Towers there was not (much if any) axial contact between column parts; [/LIST]

Forgive me if I'm behind on this, but the proof of which is where?

And if we're all now arguing about floor assemblies collapsing down around a core (in other words, back to the original FEMA hypothesis) can someone please inform NIST and/or Bazant? Because I don't think this is the official model of collapse.

 

[ozeco41]

Forgive me if I'm behind on this, but the proof of which is where?

It is nearly self evident.

Remember we are talking about the collapse stage following the initial downward movement of the top block. The fact that the top block is moving downwards means no significant axial loaded columns resisting it. The only point for discussion is "how many columns were or could have been in axial contact?" The answer to that is "not enough to hold up the top block" OR, more pedantically, sufficient when combined with friction resistances, to slow the top block down a bit.

...And if we're all now arguing about floor assemblies collapsing down around a core (in other words, back to the original FEMA hypothesis) can someone please inform NIST and/or Bazant? Because I don't think this is the official model of collapse.

I cannot speak for others here but my posts are directed to answering the question of "demolition or not?" I am not much interested in arguing for or against FEMA, NIST et al. I wouldn't have a clue from memory what the "original FEMA hypothesis" was. NIST's original position was "global collapse was inevitable" - remember what point in the collapse we are discussing. The initial collapse has just occurred and the top block is descending. From that point Bazant and Zhou said "enough energy for it to continue even if all the columns were in line". And they weren't in line transferring axial loads because the top block was falling.

Astonishing how many people miss that simple fact.

It is one point where I agree with Tony Szamboti - we just have a different explanation as to why there were no columns in contact.

And I don't think anyone would be disagreeing about "floor assemblies collapsing down around a core" - there may be different arguments as to how it was caused.

 

[R.Mackey]

An expression "like a hot knife through butter" might apply here, but I think a demonstration of it is in order:

Apologies to Howard Taylor.

haha... Schlock FTW!

His comic is much more scientifically literate than any Truther I can think of.

 

[Newtons Bit]

The original FEMA pancake theory entailed the floor trusses heating up, expanding outwards breaking the bolts holding the trusses to the columns, further heating up, sagging and then collapsing on top of the floor below. Enough floors pile up and the whole thing goes without the columns ever being drastically affected.

NIST, however, found that the vast majority of the floor trusses did not slip their bolts. Rather it was column failure that led to the initial collapse.

 

[ozeco41]

The original FEMA pancake theory entailed the floor trusses heating up, expanding outwards breaking the bolts holding the trusses to the columns, further heating up, sagging and then collapsing on top of the floor below. Enough floors pile up and the whole thing goes without the columns ever being drastically affected.

NIST, however, found that the vast majority of the floor trusses did not slip their bolts. Rather it was column failure that led to the initial collapse.

That bit I remember but it is about "initial collapse" not "global collapse" which was the stage that ergo commented on.

...not surprising I didn't see what he meant.

Thanks,

 

[Tony Szamboti]

The reason why the verinage demolition has a noticeable impact and the WTC didn't is rather simple. An offset of just a couple of inches causes a dramatic difference between an open-steel shape (such as an HSS in the WTC) and a concrete column. Observe:

[qimg]http://www.internationalskeptics.com/forums/imagehosting/thum_163294ca33ea7e99ac.jpg[/qimg]

As seen, the impact area of the concrete is still most of the original area. The column will probably fail in compression buckling.

The steel impact is about 1% of the original area, however. What does this mean? It means that about 1% of the steel shape from the upper block and 1% of of that from the lower block impact. The entirety of the force must be transmitted through this location. The local areas do not have enough capacity to develop 3mg, as Tony Szamboti likes to claim. Instead the steel will cut through each other. An expression "like a hot knife through butter" might apply here, but I think a demonstration of it is in order:

[qimg]http://www.internationalskeptics.com/forums/imagehosting/thum_163294ca33f522e512.jpg[/qimg]

Apologies to Howard Taylor.

Unfortunately for your theory, the Balzac-Vitry building's upper section moves sideways several feet and surely misses most of the lower columns, yet there is still a significant deceleration.

As for the steel column situation the high stress in the steel will cause it to deform and spread the load and the St. Venant Principle will cause any point stresses to spread a short distance away and it will not go through it like a hot knife through butter. What you are saying is an extreme stretch and essentially impossible for a generally blunt impact with a tilt angle of no more than 3 degrees maximum when the first impact should have occurred. There isn't much of an offset especially for the core columns and there certainly would be no knife edge in this situation. I would bet you could not create a model, either virtual or real, to do what you say.

 

[Newtons Bit]

Unfortunately for your theory, the Balzac-Vitry building's upper section moves sideways several feet and surely misses most of the lower columns, yet there is still a significant deceleration.

On top of that the St. Venant Principle will cause the high stress in the steel to spread a short distance away and it will not go through it like a hot knife through butter. What you are saying is an extreme stretch and essentially impossible for a tilt angle of no more than 3 degrees maximum when the first impact should have occurred. I would bet you could not create a model either virtual or real to do what you say.

You need to read your AISC again, buddy. A concentrated load will cause a local failure. The entire section will not be engaged.

End of story. You lose. Good day, sir.

 

[Tony Szamboti]

You need to read your AISC again, buddy. A concentrated load will cause a local failure. The entire section will not be engaged.

End of story. You lose. Good day, sir.

Why would you say something like this when I did say a concentrated load would cause a local deformation? My point was that it is not what you said earlier, when you were implying the impacting column would go right through the entire lower column without generating a deceleration. You certainly have no basis to tell anyone they lost here, and and your 1% contact is certainly not what would have happened. I would say that you are at a loss to explain why there was no deceleration of the upper section of WTC 1.

 

[beachnut]

Why would you say something like this when I did say a concentrated load would cause a local deformation? My point was that it is not what you said earlier, when you were implying the impacting column would go right through the entire lower column without generating a deceleration. You certainly have no basis to tell anyone they lost here, and and your 1% contact is certainly not what would have happened. I would say that you are at a loss to explain why there was no deceleration of the upper section of WTC 1.

Why do you continue spewing nonsense. The WTC collapsed at velocities matching the momentum transfer. You failed again. Your CD delusion is showing.

When will you publish a letter to Bazant like Heiwa did!?

 

[Newtons Bit]

Why would you say something like this when I did say a concentrated load would cause a local deformation?

Local deformation != local failure. Tearing and ripping isn't just a little failure you can hand waive away. It changes the internal load path inside the column to one that doesn't engage the entire section. In fact, it only engages a few square inches, see the diagram above. Strength of the member becomes the rupture stress times the cross-sectional area orthogonal to the tear. Which ain't much.

My point was that it is not what you said earlier, when you were implying the impacting column would go right through the entire lower column without generating a deceleration. You certainly have no basis to tell anyone they lost here, and and your 1% contact is certainly not what would have happened. I would say that you are at a loss to explain why there was no deceleration of the upper section of WTC 1.

The shredded and buckled ends of the columns cannot perfectly impact each other. They will be offset. Suggesting otherwise is patently ludicrous.

 

[ozeco41]

...The shredded and buckled ends of the columns cannot perfectly impact each other. They will be offset. Suggesting otherwise is patently ludicrous.

Correct.

And, if we consider the most obvious example of the outer wall columns which were pulled inwards, those columns would fail and the ends overlap in the initial collapse.

And there is no way that the overlapping ends could ever get back into axial load transferring end for end contact.

Which is the bit of the collapse scenario that Tony refuses to come to grips with.

Understandable because it nails the lid on his misguided "Missing Jolt" hypothesis.

 

[Tony Szamboti]

Local deformation != local failure. Tearing and ripping isn't just a little failure you can hand waive away. It changes the internal load path inside the column to one that doesn't engage the entire section. In fact, it only engages a few square inches, see the diagram above. Strength of the member becomes the rupture stress times the cross-sectional area orthogonal to the tear. Which ain't much.




The shredded and buckled ends of the columns cannot perfectly impact each other. They will be offset. Suggesting otherwise is patently ludicrous.

When two objects of the same hardness impact on a small area, which cannot sustain the load, there will be local deformation, which will spread the load. Knives only work on objects which are softer than they are.

After the local deformation a load amplification would be needed to go any further. Your explanation is the one that does some hand waving to proceed and to get a small contact area, as the small tilt would not cause that much misalignment.

If you think your explanation has some merit show some calculations for how it could proceed without a need for load amplification, and how you would get such a small contact area to begin with.

 

[femr2]

Few inches.

 

[pgimeno]

Unfortunately for your theory, the Balzac-Vitry building's upper section moves sideways several feet and surely misses most of the lower columns, yet there is still a significant deceleration.

I don't know how many times I've told you. Balzac-Vitry was made of load-bearing walls, not columns. The vérinage patent clearly specifies it's applicable to buildings with load-bearing walls, not columns.

I will concede that the walls are not aligned though:

(stills from the video in here: http://dubertin.blogspace.fr/218802...on-de-la-barre-DEF-a-Vitry-Banlieue-Sensible/)

Therefore the deceleration must come from the beams/floors. Obviously the walls can't possibly miss the beams here.