RFC: Bazant and Zhou Simple Analysis refuted

[Dave Rogers]

Suppose Bazant's paper is the only evidence, what does the hypothetical juror say in terms of finding the building guilty of collapse propagation?

Guilty beyond reasonable doubt. To anticipate your next question, based on your results so far and my understanding of the mechanics, I'd still say guilty beyond reasonable doubt. The requirements of legal proof are IMHO rather more lax than those of scientific proof, and at the moment with an overload of 1.00 I'd say you're precisely on the edge of scientific proof.

Dave

 

[twinstead]

Unfortunately for many truthers, Bazant's paper isn't even close to being the only evidence.

 

[GregoryUrich]

Guilty beyond reasonable doubt. To anticipate your next question, based on your results so far and my understanding of the mechanics, I'd still say guilty beyond reasonable doubt. The requirements of legal proof are IMHO rather more lax than those of scientific proof, and at the moment with an overload of 1.00 I'd say you're precisely on the edge of scientific proof.

Dave

I thought of a couple of remaining issues or extenuating circumstances if you will.

1) The upper block floor-truss structure (outer) (98) hits the lower floor (97) prior to column-column impact. Energy is consumed here, but more important, the floor is dissociated from the structure by failure at its connections (i.e. the bolts) prior to column-column impact so it's weight should not be considered in the mgh energy. Essentially the floor impact occurs prior to and independent of the column-column impact.

2) The floor support (i.e. horizontal members) will also come into contact and must fail for the columns to be able to impact each other. Here we are talking about 112 substantial members which will require a significant amount of energy. These members are probably equivalent to the columns and there are twice as many so a very conservative strain energy would be 100 MJ. No doubt this would contribute to eccentricity of the vertical columns making buckling more likely, but Bazant is ignoring this.

3) The floors of the upper part will flex significantly under the force of decelleration absorbing some amount of energy.

If these issues amount to 100 MJ and the weight is subtracted, the overload ratio would be 0.56. Just removing the single floor weight gives 0.91.

 

[GregoryUrich]

Unfortunately for many truthers, Bazant's paper isn't even close to being the only evidence.

Is there any other support for the hypothesis that gravity driven collapse would continue all the way to the ground?

 

[einsteen]

I checked NIST NCSTAR1-5A and it is amazing that all these effects are ongoing during that late period, one would expect an exponential decay of effects. On the one hand one would expect that (to initiate initiation) there is always a very small movement (like I remember Greening saying) of the top section, a constant but small angular motion (too small to be measured within the resolution of the images) because that explains (from a theoretical point of view) how small rotational energy can "overcome" resistance.

If you look at a simple theoretical 1d model then imho you can never prove that initiation is possible if there is no initial movement, even when there is initial movement it is very difficult because a small velocity implies Ekin<E1 and that is something that will be arrested. If E1 for the weakest story is very low then a small initial movement can be overcomed (sorry if that is no proper English) but then the next story will do its job. Of course the real situation is a complex 3d model, but I think it is strange that the strain energy of the other walls (west, east, intact part of north) seems to have no affect and then also not the core itself that is still there!, the rotational energy is very low and why isn't that absorbed ? Anyone can explain that ? Mackey, Dave, Newtons, Apollo20 , Greg, Heiwa etc ?

 

[Dave Rogers]

I thought of a couple of remaining issues or extenuating circumstances if you will.

1) The upper block floor-truss structure (outer) (98) hits the lower floor (97) prior to column-column impact. Energy is consumed here, but more important, the floor is dissociated from the structure by failure at its connections (i.e. the bolts) prior to column-column impact so it's weight should not be considered in the mgh energy. Essentially the floor impact occurs prior to and independent of the column-column impact.

2) The floor support (i.e. horizontal members) will also come into contact and must fail for the columns to be able to impact each other. Here we are talking about 112 substantial members which will require a significant amount of energy. These members are probably equivalent to the columns and there are twice as many so a very conservative strain energy would be 100 MJ. No doubt this would contribute to eccentricity of the vertical columns making buckling more likely, but Bazant is ignoring this.

3) The floors of the upper part will flex significantly under the force of decelleration absorbing some amount of energy.

These are all valid points, but in considering them you now have to consider whether they separate the floors from the columns, and, if so, whether pancake failure of the floors is going to take place as a result. You'd then need to work out the energetics of a floor-by-floor-with-off-axis-column-impacts collapse, which I suspect would be far more energetically favourable than a 1-D model.

By even raising those issues you're asserting that the Bazant model is inadequate to analyse the collapse, so you're implicitly saying that a more complex model that treats the floors separately from the columns is needed. I'd be inclined to agree with that, but it appears computationally intractable. In short, rather than refuting Bazant's conclusions, you've challenged the validity of his model.

Is there any other support for the hypothesis that gravity driven collapse would continue all the way to the ground?

There are some very simple energetic considerations that imply that if floor 98 collapses floor 97 then the collapse will propagate, and Greening's papers are probably the best analysis of them. 98 on 97 is the crux, though. I wonder whether that would be possible to model in a 3D approximation?

Of course, there's also the negative evidence side of things, in that no plausible evidence has been brought forward for anything other than gravity driven collapse, and the absence of flash and sufficiently loud reports strongly suggests the absence of explosives. I realise you may see that as an evasion, but it places a strong burden of proof on those challenging gravity driven collapse; you need to prove it was physically impossible, not just unlikely, because it would need to stand alone as evidence.

Dave

 

[Heiwa]

Coming back to the now infamous photo of WTC1 South face at 10.23 am Therese McAllister of Nist admits that most values of indent depth indicated on the photo are uncertain as the area is covered by smoke on the photo. OK, so the obvious question is then why not use another photo, without smoke? I.e. do a better job!

 

[e^n]

Coming back to the now infamous photo of WTC1 South face at 10.23 am Therese McAllister of Nist admits that most values of indent depth indicated on the photo are uncertain as the area is covered by smoke on the photo. OK, so the obvious question is then why not use another photo, without smoke? I.e. do a better job!

NIST used several photos for each tower, it's very hard to get a picture without smoke when the towers are pouring out smoke.

 

[Major_Tom]

It is the 1-D aspect to the model which forces the analysis down a very narrow path.

1-D means that falling object MUST hit objects below it.

In a 3-D model objects can fall right past other objects and miss them completely.

In the case of columns they may hit floor panels (this is much more highly probable).


Dave, I'm guessing you would go on to reason that this would leave many lower block columns without lateral support and they will fall from their own weight.

But how would that lead to such a COMPACT collapse front as seen in the following picture.


http://www.sharpprintinginc.com/911_math/collapse_cloud.jpg[/IMG



[QUOTE]Of course, there's also the negative evidence side of things, in that no plausible evidence has been brought forward for anything other than gravity driven collapse, and the absence of flash and sufficiently loud reports strongly suggests the absence of explosives.[/QUOTE]


In other threads it has been noted that the core column-to-column welds were very vulnerable to lateral impacts just along the weld on the long side of the rectangular cross-section.

It was argued by Newtons Bit among others that it wouldn't require much of a "kick" to crack the weld.


Of the methods used to split the main support columns mentioned by those crazy truthers, wouldn't this be the easiest choice for demolition planners?

To what degree would you expect to see flashed if these small devices were installed inside elevator shafts inside the core?

How loud would the individual popping sounds need to be if the welds are so easy to crack, as NB mentions?

 

[twinstead]

Coming back to the now infamous photo of WTC1 South face at 10.23 am Therese McAllister of Nist admits that most values of indent depth indicated on the photo are uncertain as the area is covered by smoke on the photo. OK, so the obvious question is then why not use another photo, without smoke? I.e. do a better job!

Of course. They just needed to do a better job.

And perhaps they should have used the close-up images the special mini camera-equipped seeing-through-smoke flying pink unicorns the fire department released just before the collapses.

I find the lack of those images quite suspicious, don't you?

 

[twinstead]

Of the methods used to split the main support columns mentioned by those crazy truthers, wouldn't this be the easiest choice for demolition planners?

To what degree would you expect to see flashed if these small devices were installed inside elevator shafts inside the core?

How loud would the individual popping sounds need to be if the welds are so easy to crack, as NB mentions?

Unless you can provide ANY evidence of these things, all it appears to be to an observer is hand waving away lack of evidence of CD by thinking up ways it could be accomplished, a la Max Photon. Seriously, conjecture is fun to a point but not if you are attempting to pin a mass murder rap on somebody. You'll need to do better than that.

What are you conducting, a think tank or an investigation?

 

[Dave Rogers]

Dave, I'm guessing you would go on to reason that this would leave many lower block columns without lateral support and they will fall from their own weight.

But how would that lead to such a COMPACT collapse front as seen in the following picture.

Look at the picture yourself. At the bottom of the collapse front you can see a large section of perimeter columns that's falling outwards and away from the tower. If you look at the post-collapse images, you can see perimeter column trees, which have fallen away a distance several times the width of the towers. This is one side of those classic truther two-way arguments, where the debris field is at once too big and too small; these arguments only survive because their proponents won't make predictions. How big would you expect the collapse front to be if what we can see in your picture is actually happening?

Of the methods used to split the main support columns mentioned by those crazy truthers, wouldn't this be the easiest choice for demolition planners?

Non-evidence. If both the gravity collapse hypothesis and the CD hypothesis point to the weld planes as the point of fracture, then the identification of the weld planes as the point of fracture is of zero value in distinguishing between them. In fact, though, it's only the gravity hypothesis that points unequivocally to the weld planes as the point of failure; for the CD hypothesis, what you're proposing is actually a complicating factor, in that it places an unnecessary constraint on the placement of charges. You don't realise it, but you're actually presenting a fairly weak argument against CD.

To what degree would you expect to see flashed if these small devices were installed inside elevator shafts inside the core?

How loud would the individual popping sounds need to be if the welds are so easy to crack, as NB mentions?

Denying the possibility of evidence in favour of your hypothesis does not strengthen your hypothesis.

Dave

 

[Major_Tom]

Non-evidence. If both the gravity collapse hypothesis and the CD hypothesis point to the weld planes as the point of fracture, then the identification of the weld planes as the point of fracture is of zero value in distinguishing between them.

Non-evidence but clearly the natural Achille's Heel within the buildings.

Both the CD and nonCD viewpoints MUST see the weld planes as the point of fracture because there is clear and overwhelming forensic photographic evidence for this.

Your point about not being able to distinguish between the 2 by looking at the welds surfaces themselves captures the essence of the argument well.

From the CD planning perspective this is pure genius.


Actually, charge placement is will utilize elevator shafts. The chief targets will be the 500 and 1000 columns. These are the most accessible through elevator shafts.

You don't realise it, but you're actually presenting a fairly weak argument against CD.

I did realize that even though people were unable to notice that the "hinges" were welds and they are separated by 38 feet, more or less, as soon as I pointed it out it would be received as further evidence towards a gravity driven collapse.

But don't we all want to know the TRUE mechanism of collapse? And isn't this information vital to that purpose?

If a person is able to think " few moves ahead", after the knee-jerk mental reaction they will realize that weld plane failure and 47 very straight 38 foot long columns all welded at the exact same elevations are not necessarily consistent with gravity collapse.

In my last point about the flashes, I was just passing the idea that the devices don't have to be that powerful and will be located for the most part in elevator shafts.


Remember the "spire" argument I gave earlier? I claim the spire consists of columns from only column rows 700 and 800. You mentioned 500 and 600 are good choices, too.

Good eye. Not many people would have noticed that so quickly (meaning you skipped the other possibilities: 600, 700 ect)

The 700 and 800 columns have a unique geometrical layout and it is not difficuly to distinguish them from the 500-600 row.

I'll hold off on the argument for now, but I know that you are smart enough to know that if the spire consists of 700-800 columns only, your notion about weld failure gravity driven collapse goes right out the window.

Thanks for your thoughtful response.

 

[Newtons Bit]

And then of course Pdyn is dependent on the stiffness which the displacement is dependent on...

Using your value of 414MJ (should be somewhat less) for the losses in the initial failure and 4m/sec. The wave propagates all the way to the ground. I'm still splitting the energy evenly between the upper and lower springs which isn't realistic. I end up with an overload ratio of 1.00.

Where did I say 414MJ again? Typo?

 

[Dave Rogers]

Your point about not being able to distinguish between the 2 by looking at the welds surfaces themselves captures the essence of the argument well.

From the CD planning perspective this is pure genius.

That's rather a tenuous argument. You're saying that the columns fractured exactly where they would have been expected to fracture, proving that the conspirators designed the collapse in such a way that they would fracture exactly where they were expected to fracture. That's just the "no evidence of a conspiracy is evidence of a conspiracy" argument.

I did realize that even though people were unable to notice that the "hinges" were welds and they are separated by 38 feet, more or less, as soon as I pointed it out it would be received as further evidence towards a gravity driven collapse.

I wish you would stop pretending to be the only person to have noticed this. It was, as Gravy keeps repeating, well-known before you came to this forum.

http://www.911myths.com/html/30_foot_lengths_of_steel.html

I'll hold off on the argument for now, but I know that you are smart enough to know that if the spire consists of 700-800 columns only, your notion about weld failure gravity driven collapse goes right out the window.

No, nothing of the sort. The collapse was a far more complex event than any of the models of it that can feasibly be constructed. To take a very simple model of such a collapse and make a confident prediction from it that only the weaker core columns will collapse is completely unwarranted. By the time the collapse has progressed to floor 50, there are large pieces of debris and framing that have fallen considerable distances impacting eccentrically on all parts of the surviving core. The shocks to the floors will be most efficiently transmitted to the outermost core columns. Any perimeter columns that fall inwards or are deflected inwards - note that, by conservation of momentum, any event that throws a perimeter column outwards must throw something else inwards - will impact sideways on the outermost core columns. The corner columns are the strongest, but they're also the most vulnerable to damage during collapse. I would not accept that any specific subset of core columns surviving was anomalous in such a complex process. What you're suggesting is perilously close to the Texas Sharpshooter fallacy; how could that particular set of columns be expected in advance to have survived the initial collapse? The answer is that the choice was not preordained.

Dave

 

[GregoryUrich]

Where did I say 414MJ again? Typo?

In your analysis refuting Ross. It's the combined elastic and plastic strain energy for the lower floor, adjusted for strain rate. But you used a larger cross-sectional area so it should be somewhat less.

 

[Newtons Bit]

In your analysis refuting Ross. It's the combined elastic and plastic strain energy for the lower floor, adjusted for strain rate. But you used a larger cross-sectional area so it should be somewhat less.

What? How dare you use my own work against me!

I may have comments about this later.

 

[GregoryUrich]

Non-evidence but clearly the natural Achille's Heel within the buildings.

Both the CD and nonCD viewpoints MUST see the weld planes as the point of fracture because there is clear and overwhelming forensic photographic evidence for this.

Your point about not being able to distinguish between the 2 by looking at the welds surfaces themselves captures the essence of the argument well.

From the CD planning perspective this is pure genius.


Actually, charge placement is will utilize elevator shafts. The chief targets will be the 500 and 1000 columns. These are the most accessible through elevator shafts.



I did realize that even though people were unable to notice that the "hinges" were welds and they are separated by 38 feet, more or less, as soon as I pointed it out it would be received as further evidence towards a gravity driven collapse.

But don't we all want to know the TRUE mechanism of collapse? And isn't this information vital to that purpose?

If a person is able to think " few moves ahead", after the knee-jerk mental reaction they will realize that weld plane failure and 47 very straight 38 foot long columns all welded at the exact same elevations are not necessarily consistent with gravity collapse.

In my last point about the flashes, I was just passing the idea that the devices don't have to be that powerful and will be located for the most part in elevator shafts.


Remember the "spire" argument I gave earlier? I claim the spire consists of columns from only column rows 700 and 800. You mentioned 500 and 600 are good choices, too.

Good eye. Not many people would have noticed that so quickly (meaning you skipped the other possibilities: 600, 700 ect)

The 700 and 800 columns have a unique geometrical layout and it is not difficuly to distinguish them from the 500-600 row.

I'll hold off on the argument for now, but I know that you are smart enough to know that if the spire consists of 700-800 columns only, your notion about weld failure gravity driven collapse goes right out the window.

Thanks for your thoughtful response.

MT,

I think the charges would need to be even larger than cutter-charges for your proposed demolition method. Cutter-charges are placed at an angle so gravity does the rest. Just breaking the welds won't do anything. The columns would need to be displaced. Each one has at least 6 horizontal members connected to it and there is at least 2000 tons pressing down on each of the columns you are talking about. Also, they need to be displaced entirely, otherwise the ends will have a different damage pattern.

I'm not as smart as Dave, could you explain?

 

[Major_Tom]

Yes. The question is what would be the minimum lateral "kick" necessary to crack the weld and kick it sufficiently.

If you use too much explosive you could get something like this:

The column above is one of the rare columns that was actually bent along it's length.




Dave, I know these are not proof.

Don't they make you folks think a bit?

 

[DGM]

Yes. The question is what would be the minimum lateral "kick" necessary to crack the weld and kick it sufficiently.

[qimg]http://www.sharpprintinginc.com/911_old/Photo%20archives/bomb%20marks/God%20Bless2.jpg[/qimg]

If you use too much explosive you could get something like this:

[qimg]http://www.sharpprintinginc.com/911_old/Photo%20archives/bomb%20marks/AZ-TF-Pole-cam0541_z1.jpg[/qimg]

The column above is one of the rare columns that was actually bent along it's length.




Dave, I know these are not proof.

Don't they make you folks think a bit?

Why can't these explosives be heard?