Merged Applicability of Bazant's model to the real world

[Major_Tom]

The OP is "Applicability of Bazant's model to the real world" and I am clear where the assumptions lie for Bazant and Zhou.

I am not clear where the assumptions apply to limit applicability of Bazant's later work with other collaborators. I had been hoping that someone could clarify things for me but it looks like I will have to do the hard mental graft of working through all the papers.

I could, but who would be capable of understanding what I say?

Step 1: Realize there is no "Bazant model". There are 2 distinct models haveing very different applications and purposes. The BZ model covers a single impact between columns that fall 12 ft and land dirctly upon one another. It was presented in 2001 and 2002.

The second model is a collapse propagation model, governed by different equations and presented for an entirely different purpose. It is first presented in BV in 2007 and expanded upon through the BL and BLGB papers in 2008.

The single biggest source of confusion is that people on this forum cannot distinguish between the 2 models and blur them together.

Each model must be studied and understood separately, or people begin to speak jabberwockey. When you combine the "best case scenario" approach in the BZ model with the crush up, crush down equations of motion for the collapse progression model (BV eqs 12 and 17), you get a big freaking mess.

If you combine that ignorance with vanity and pride, you get something like this thread.

Edited by Locknar: 

Edited to correctly reflect quoted material.

 

[Oystein]

...but who would be capable of understanding what I say?...

Hahaha
I know several here are capable of understanding where you err.
Given the trouble you have over at the other thread, you got some nerves pretending you could teach anyone about Bazant (and his alleged shortcomings).

 

[ozeco41]

The OP is "Applicability of Bazant's model to the real world" and I am clear where the assumptions lie for Bazant and Zhou.

I am not clear where the assumptions apply to limit applicability of Bazant's later work with other collaborators. I had been hoping that someone could clarify things for me but it looks like I will have to do the hard mental graft of working through all the papers.

I could, but who would be capable of understanding what I say?

Step 1: Realize there is no "Bazant model". There are 2 distinct models haveing very different applications and purposes. The BZ model covers a single impact between columns that fall 12 ft and land directly upon one another. It was presented in 2001 and 2002.

Yes. That one I am clear on. Misunderstanding of it is central to the starting premise errors that undermine the "Missing Jolt" paper and I have posted at some length on that.

...The second model is a collapse propagation model, governed by different equations and presented for an entirely different purpose. It is first presented in BV in 2007 and expanded upon through the BL and BLGB papers in 2008....

That much I already understand. AND the fact that the two are completely different things.

...The single biggest source of confusion is that people on this forum cannot distinguish between the 2 models and blur them together....

Also known. It is not so much the separate the two models - rather I am unsure how far the second or 'generic progression' model can be taken in application to WTC or any other specific target.

...Each model must be studied and understood separately, or people begin to speak jabberwockey. When you combine the "best case scenario" approach in the BZ model with the crush up, crush down equations of motion for the collapse progression model (BV eqs 12 and 17), you get a big freaking mess....

...and it is just that sort of mess where, at this stage, I am not confident in correcting mistaken posts beyond saying "you are confusing different things".

Bottom line is I prefer to be fully on top of understanding something before I go in boots and all to correct someone. I think I react more like a teacher trying to explain rather than a debater trying to win points.

Thanks for the explanation.

...If you combine that ignorance with vanity and pride, you get something like this thread.

The "noise to signal" ratio can get a bit high.

 

[Major_Tom]

That much I already understand. AND the fact that the two are completely different things.

Then you are way ahead of the curve already.

If you do not distinguish the 2 models you begin to believe that BV is about the mechanics of progressive collapse of best possible scenarios for survivability, or some such nonsense.

Why on earth would Bazant write three papers on the mechanics of a theoretical crush down model of the case for optimum survivability that has no application in the real world?

The simplest logical reality checks applied to BV, BL and BLGB and we wouldn't be having this conversation.

Bazant is obviously trying to model the collapse of real buildings in BV and the real behavior of WTC1 in BLGB just as he explicitly states

Here is another simple reality check you can apply: Go to BL at the link I provided and explain what sections 3, 4 and 5 mean.

Nobody here can do that. Sections 3, 4 and 5 demonstrate how totally gullible the regular posters have been. How can anyone read that and not sense a problem with the paper?

How can anyone miss such obvious signs that something is not quite right here?

 

[pgimeno]

MT,

Are you talking about enik's FEA, or about Bazan'ts papers?

Because reading your notes I could not really distinguish which one you're talking about. Your conclusions apply equally well to either.

 

[ozeco41]

That much I already understand. AND the fact that the two are completely different things.

Then you are way ahead of the curve already.

If you do not distinguish the 2 models you begin to believe that BV is about the mechanics of progressive collapse of best possible scenarios for survivability, or some such nonsense.

Why on earth would Bazant write three papers on the mechanics of a theoretical crush down model of the case for optimum survivability that has no application in the real world?

The simplest logical reality checks applied to BV, BL and BLGB and we wouldn't be having this conversation.

Bazant is obviously trying to model the collapse of real buildings in BV and the real behavior of WTC1 in BLGB just as he explicitly states

Here is another simple reality check you can apply: Go to BL at the link I provided and explain what sections 3, 4 and 5 mean.

Nobody here can do that. Sections 3, 4 and 5 demonstrate how totally gullible the regular posters have been. How can anyone read that and not sense a problem with the paper?...

...memory returns. That - Section 3 onwards - is where my alarm bells rang when I first saw the paper - probably a couple of years back - but I turned away from the issue - mental laziness. He seems to be treating the tower sections as if they are homogeneous entities and has no regard for the clear fact that collapse progression (of the WTC Twin Towers to be precise) is three main and distinct processes. First the separation of outer columns which then took no further part in the process. Second the pancaking of the open office space which has stuff all interaction with the columns either core or outer. Then, third, the core which may lend itself to treatment in a similar manner to a traditional grid block layout building. At that point I reserved judgement allowing him benefit of the doubt that somehow he was not ignoring these real factors OR that some magic of his maths, hidden from my comprehension, would roll up the massive assumptions.

And no way could I, make that 'can I', reconcile "crush down - crush up" with the three clearly separate processes of the Twin Towers global collapses. To me the concept requires some integral homogeneity of the two parts of tower and no amount of fancy maths seems to explain that away. So, if it is sus on that bit it could well be sus on other parts. And that is about as far as my thinking went.

...How can anyone miss such obvious signs that something is not quite right here?

Didn't miss the signs. I simply hadn't worked through the concepts to assure myself either way. And I will not attack an authority until I am sure of my ground.

Note I used the word "attack" there with some precision. I have previously commented on the use of the word "attack" in this thread. Finding and describing where the bounding assumptions limit applicability is not "attack". It is accepting what the authority says whilst explaining or clarifying it. Not disagreeing. When we start disagreeing it can become attack. I am still some distance from "attack". But I am getting clearer on the boundaries set by assumptions.

 

[tfk]

MT,

If I may paraphrase the inimitable Inigo Montoya …

"You say all these words. I do not think that Bazant's papers mean what you think they mean."

I had been hoping that someone could clarify things for me

I could, but who would be capable of understanding what I say?

LoL...
Probably true.
But the explanation for this may not be the first one that jumps to your mind.

But why don't you try to explain it anyway. In your own words, please.
It's always enlightening & entertaining whenever you guys screw up the courage to actually say anything.

Step 1: Realize there is no "Bazant model". There are 2 distinct models haveing very different applications and purposes.

Nope.

The BZ model covers a single impact between columns that fall 12 ft and land dirctly upon one another. It was presented in 2001 and 2002.

The second model is a collapse propagation model, governed by different equations and presented for an entirely different purpose.

Gee, one might think that, if someone had generated a "single story collapse model", and they were subsequently interested in generating a "multi-story collapse model", then that single story collapse model might be a great place to start.

Especially since all the fundamental principles that apply to a single story collapse also apply to a multi-story collapse.

Pretty strange that someone as sharp as Bazant would start all over with a brand new "distinct" model.

Why don't you go ahead and explain the differences between the "two distinct models".

First principles (not ultimate purposes) would be a good place to start.


tk

 

[tfk]

This is a good thread. Finally something to read again on JREF.

I am wondering why tfk did not address enik's post #1075 wherein he asks tfk to post some jpegs of his catheter design. TFK posted instead a link to the NIST WTC FAQ. -- ??? WTF? I know that bee dunkers have a tendency not to answer simple, straightforward questions, but such a response that is so blatantly fake is shocking, even by bee dunker standards.

You're too easily shocked.

My catheter is not the topic of conversation. The WTC towers are.

enik claims that he has produced an FEA model of several floors of the towers.

I have zero interest in going thru the details of that model when:

1. several of his statements have demonstrated a severely limited understanding of FEA (e.g., modeling the truss seats as rigid fixed constraints).

2. No competent person has reviewed his work (AFAIK)

3. he has been invited repeatedly to elaborate on his job function, but has pointedly refused.

4. There exists a far, far more detailed FEA model that has been generated by experienced professionals, cross checked by experienced professionals, and explained in fine detail by those experienced professionals.

So I gave him a reference to the FEA model that I believe is pertinent to this discussion. And invited him to point out exactly what they got wrong, and what the correct answers should have been.

There has been a deafening silence ever since...

 

[Major_Tom]

Ozeco and anyone who wants to understand what the Achille's heels of BL really are:


BL relinked: http://www.civil.northwestern.edu/people/bazant/PDFs/Papers/D25.pdf

It is important that you look at sections 4 and 5 very carefully and understand them. That is the heart of the mechanics argument. If you do, you will understand just how bad the BV collapse propagation model really is.



Section 4: Entitled "Can crush up proceed simultaneously with crush down?"

Bazant begins to explain, "It can, but only briefly at the beginning of collapse, as mentioned in the paper" (BV).

He then goes on to "prove" why it "can't". Only a true disciple of Bazant can read this and believe what he says. What a crock!

These explanations have led to his disciples preaching the Doctrine of "crush up, then crush down" throughout the land. People wished to believe so badly that they began to hallucinate upper blocks themselves. No kidding. I gave 3 examples earlier of R Mackey, Dave Rogers and Newton's Bit hallicinating an upper block just as the Master has preached. Notice they also insult those who can see past the illusion. Very typical of a true believer. They couldn't actually see the "upper block" descend to earth because of "all that dust" but the faithful knew that the block was in there somewhere because their master had "proven" it exists using "Newton's Laws".

To me, this is pure gullibility. Looks like physics but is is only a form of hypnotism.

And honestly, is there any difference between them and those they criticize at AE911T for their poor use of physics?


This is probably the single worst application of physics to WTC1 I've seen Bazant make.

Now here is a test question. If you can answer it correctly, you will understand the root of his mistake.

What, according to Bazant, prevents "crush up" from occurring until has famous "block" contacts earth?


The answer is somewhere is sections 4 and 5. Can you spot it? When you do, you will understand why this paper is such a freaking joke.

(if you cannot, let me know and we'll go over it together.)


I'd love to hear what R Mackey, rocket scientist, and TFK, engineer and mighty intellectual, have to teach us little people about the true meaning of sections 4 and 5.

 

[ozeco41]

Ozeco and anyone who wants to understand what the Achilles heels of BL really are:....

It is hard work reading that paper - I am years out of practice. What I look for is "what is the underlying model which the academic style hides behind a fog of mathematics and which may be based on a totally wrong foundation"

I made that same type of observation in the first post I ever made on the internet. Richard Dawkins Net Forum, 13/14 (depending on time zone) Nov 2007 when I said this:

Re: World Trade Center? What Really Happened?

The supporters of 9/11 conspiracies build on the same foundation as the creationists - poor logic, worse science together with distortions, lies and deliberate deceptions.

The paper referenced as 'Engineering Reality' by Tony Szamboti is typical of many which look impressive in detail to the non-engineer. The complex calculations may even be correct but the base premises are faulty and the resulting conclusions can readily be demonstrated to be totally wrong....

So when I work through papers such as Bazant et al and I see things which don't look correct then:

• I check to see if he is talking about WTC - the real towers - not some generic imaginary construct; AND
• I examine what he says to see if it fits the observed realities of how the actual collapse occurred.

One part of the BL paper attracted my attention:

The result is that the crush-up stops i.e drops to zero when the first overlying story is squashed by the distance of only about 1.0% of its original height for the North Tower, and only by about 0.7% for the South Tower these values are about 11 or 8 times greater than the elastic limit of column deformation. Why is the distance smaller for the South Tower even though the falling upper part is much more massive? That is because the initial crush-up velocity is similar for both towers, whereas the columns are much stronger in proportion to the weight carried....

So he is talking about WTC1 and WTC2 and BUT says "...whereas the columns are
much stronger in proportion to the weight carried...."

Which columns? Which columns resisted collapse in the Twin Towers?

So prima facie his paper is based on a wrong model. Therefore it is not applicable to WTC collapse. I do not need Bazant as an authority to support my understanding of the WTC Global Collapse. BL is excluded on the basis of that one section. And I will put the other Bazant papers (other than BZ) into the category of "dubious" when applied to WTC collapse.

Now in a previous post I made a clear distinction between "attacking" Bazant's work and "explaining" the limits of validity of his work.

That one example leads me to accept that his work is faulty as applied to WTC collapse. I remain open to being persuaded that my understanding is wrong but, so far, I cannot recall anyone addressing in detail the type of concern I identify.

However I have no interest in attacking Bazant or his disciples here nor in taking Bazant on in the academic circles of published papers etc. That academic arena has never been my interest. My interest is is knowing where the bounding assumptions of his paper limit applicability of his work to my understanding of the actual collapses which occurred at WTC on 9/11. And any limits they pace on my ability to explain 9/11 collapses to interested other persons who are interested - whether on Internet forums or in face to face contacts.

That means that I have no interest in joining this challenge:

...I'd love to hear what R Mackey, rocket scientist, and TFK, engineer and mighty intellectual, have to teach us little people about the true meaning of sections 4 and 5.

..whilst ever it is expressed in such inappropriate language.

 

[enik]

You're too easily shocked.

My catheter is not the topic of conversation. The WTC towers are.

enik claims that he has produced an FEA model of several floors of the towers.

I have zero interest in going thru the details of that model when:

1. several of his statements have demonstrated a severely limited understanding of FEA (e.g., modeling the truss seats as rigid fixed constraints).

2. No competent person has reviewed his work (AFAIK)

3. he has been invited repeatedly to elaborate on his job function, but has pointedly refused.

4. There exists a far, far more detailed FEA model that has been generated by experienced professionals, cross checked by experienced professionals, and explained in fine detail by those experienced professionals.

So I gave him a reference to the FEA model that I believe is pertinent to this discussion. And invited him to point out exactly what they got wrong, and what the correct answers should have been.

There has been a deafening silence ever since...

Need a lesson in FEA 101?

 

[Newtons Bit]

Need a lesson in FEA 101?

There's nothing in his statement that requires correction. Got logic 101?

 

[rwguinn]

There's nothing in his statement that requires correction. Got logic 101?

You nailed that one.
Constrained the seats in rotation? Conservative? Conservative for what?
whoo-boy

 

[tfk]

Need a lesson in FEA 101?

Sure, kid. Give it a shot.

 

[Newtons Bit]

You nailed that one.
Constrained the seats in rotation? Conservative? Conservative for what?
whoo-boy

I'm going to start using moment connected trusses in my buildings from now on. It's obviously more (un?)conservative.

 

[newton3376]

Ozeco and anyone who wants to understand what the Achille's heels of BL really are:


BL relinked: http://www.civil.northwestern.edu/people/bazant/PDFs/Papers/D25.pdf

It is important that you look at sections 4 and 5 very carefully and understand them. That is the heart of the mechanics argument. If you do, you will understand just how bad the BV collapse propagation model really is.



Section 4: Entitled "Can crush up proceed simultaneously with crush down?"

Bazant begins to explain, "It can, but only briefly at the beginning of collapse, as mentioned in the paper" (BV).

He then goes on to "prove" why it "can't". Only a true disciple of Bazant can read this and believe what he says. What a crock!

These explanations have led to his disciples preaching the Doctrine of "crush up, then crush down" throughout the land. People wished to believe so badly that they began to hallucinate upper blocks themselves. No kidding. I gave 3 examples earlier of R Mackey, Dave Rogers and Newton's Bit hallicinating an upper block just as the Master has preached. Notice they also insult those who can see past the illusion. Very typical of a true believer. They couldn't actually see the "upper block" descend to earth because of "all that dust" but the faithful knew that the block was in there somewhere because their master had "proven" it exists using "Newton's Laws".

To me, this is pure gullibility. Looks like physics but is is only a form of hypnotism.

And honestly, is there any difference between them and those they criticize at AE911T for their poor use of physics?


This is probably the single worst application of physics to WTC1 I've seen Bazant make.

Now here is a test question. If you can answer it correctly, you will understand the root of his mistake.

What, according to Bazant, prevents "crush up" from occurring until has famous "block" contacts earth?


The answer is somewhere is sections 4 and 5. Can you spot it? When you do, you will understand why this paper is such a freaking joke.

(if you cannot, let me know and we'll go over it together.)


I'd love to hear what R Mackey, rocket scientist, and TFK, engineer and mighty intellectual, have to teach us little people about the true meaning of sections 4 and 5.

Why should anyone bother MT?

All you do is bluff about physics...

It's painfully obvious that you are NOT an engineer or scientist and have only a basic knowledge of mathematics.

So why should they bother to spend the time to explain any of this to you? You make mistake after mistake after mistake.....and when they are corrected you just make vague and general comments about how "everyone is wrong" but we rarely see any mathematics or physics from you.

The few times you have attempted to delve into a little bit of math you were shown to be in error....so why should anyone bother with you?

You don't understand the papers you are whinging about....why bother talking to someone who won't understand anyway? It's just a waste of time because you lack the basic foundational physics/math knowledge and do not have any engineering experience.

Just because uneducated and clueless truthers might think you sound impressive doesn't mean those of us who know any better would think that.

And as you can see....we find your arguments VERY unimpressive.

 

[tfk]

MT,
… But why don't you try to explain [the difference between the BZ & BV models] anyway. In your own words, please.
It's always enlightening & entertaining ...

Step 1: Realize there is no "Bazant model". There are 2 distinct models haveing very different applications and purposes.

Nope.

[crickets]

I'll accept your silence as "your bluff called, and you folding".

Followed by this nonsense

It is important that you look at sections 4 and 5 very carefully and understand them. That is the heart of the mechanics argument. If you do, you will understand just how bad the BV collapse propagation model really is.



Section 4: Entitled "Can crush up proceed simultaneously with crush down?"

Bazant begins to explain, "It can, but only briefly at the beginning of collapse, as mentioned in the paper" (BV).

He then goes on to "prove" why it "can't". Only a true disciple of Bazant can read this and believe what he says. What a crock!

These explanations have led to his disciples preaching the Doctrine of "crush up, then crush down" throughout the land.

It would help you credibility if you could at least get the order right.
"crush down, then crush up".

People wished to believe so badly that they began to hallucinate upper blocks themselves. No kidding. I gave 3 examples earlier of R Mackey, Dave Rogers and Newton's Bit hallicinating an upper block just as the Master has preached. Notice they also insult those who can see past the illusion. Very typical of a true believer. They couldn't actually see the "upper block" descend to earth because of "all that dust" but the faithful knew that the block was in there somewhere because their master had "proven" it exists using "Newton's Laws".

To me, this is pure gullibility. Looks like physics but is is only a form of hypnotism.

This is a fine example of projection, MT.

Since you don't understand the mechanics, you project onto people that do understand the only tool that you can wield: a sycophant's Appeal to Authority.

Your limitations are not everyone's limitations.

And honestly, is there any difference between them and those they criticize at AE911T for their poor use of physics?

There are 3 types of "physics" users at AE91T.

1. The vast majority, who may (highly unlikely) or may mot (almost certainly) have a clue about "physics". It's impossible to tell, because on they "issue of the century", they choose to stay silent.

2. The few who publish, like Gage, Bjorkman & Szamboti [& BTW you & femr], and prove beyond doubt that they haven't the slightest clue about "physics".

3. Those (like Jones & Chandler) who understand physics just fine, but fall on their face because this "physics" is really engineering.

And this is a perfect example. All the physics in BZ & BV is pure & pristine. All of the limitations of the model (what you may quaintly refer to as the errors) reside in the engineering, not the physics.

This is probably the single worst application of physics to WTC1 I've seen Bazant make.

It's so cute when you use words you don't understand.

Like "physics".

Now here is a test question. If you can answer it correctly, you will understand the root of his mistake.

What, according to Bazant, prevents "crush up" from occurring until has famous "block" contacts earth?


The answer is somewhere is sections 4 and 5. Can you spot it? When you do, you will understand why this paper is such a freaking joke.

(if you cannot, let me know and we'll go over it together.)


I'd love to hear what R Mackey, rocket scientist, and TFK, engineer and mighty intellectual, have to teach us little people about the true meaning of sections 4 and 5.

Well, MT, you get your wish.

Walk me thru it.

This should be HIGHLY entertaining...

tk

PS. First you'll have to demonstrate that you understand Bazant's model (according to you, "models"). So providing "the answer that you could give, but could anyone here at JREF understand" would be a good (and, I'm sure, an amusing) start.

 

[rwguinn]

I'm going to start using moment connected trusses in my buildings from now on. It's obviously more (un?)conservative.

Damn! There goes the value of my Rigidium stock!
Think of all the money you'll save on materials.

 

[Newtons Bit]

Damn! There goes the value of my Rigidium stock!
Think of all the money you'll save on materials.

I just need to find a way to to prevent the floors from buckling due to building sway.

 

[rwguinn]

I just need to find a way to to prevent the floors from buckling due to building sway.

Guy wires.
Or flying buttresses. I hear they are making a comeback...