Merged Applicability of Bazant's model to the real world

[tfk]

Wrong Benson. Try this one.

Bazant, Z.P., Le, J.-L., Greening, F.R., and Benson, D.B. (2008). “What did and did not cause collapse of World Trade Center twin towers in New York?”. J. of Engrg. Mechanics ASCE 134 (10) 892–906. (5), p. 54.

Are there really two David Bensons?

 

[ozeco41]

...In the graph above, the work done crushing (whatever) from 0 to z2 using the force curve F(z) is the sum of the area W1 + CA. (Where CA = the common area = the orange area.)

The work done crushing the same (whatever) from 0 to z2 using a constant force Fc is equal to W2 + CA....

(...my emphasis added.)
Let's not forget that a large part of the concerns with Bazant's papers is whether or not the findings apply to WTC Twin Towers collapse.

Which, of course, requires careful consideration of what you dismiss with the word "whatever". What does Bazant consider was "crushed" at WTC as distinct from what he includes as "crushed" in his objective of developing a more generic model.

 

[ozeco41]

Are there really two David Bensons?

I dunno.

Odds must favour many.

 

[Cuddles]

Derail removed to AAH. Stay on topic. For the forgetful, the topic is not when someone edited their post.

Replying to this modbox in thread will be off topic  Posted By: Cuddles

 

[Major_Tom]

TFK post 1312: "
The question is "WHY are they defined to be equal?""

Two sections later Bazant reformulates as a continuous model. He will replace the varying curve with an average equivalent value.

That is why he does it. Explained in more detail in BL.

My mistake in the last posts.

 

[femr2]

Derail removed to AAH. Stay on topic. For the forgetful, the topic is not when someone edited their post.

Replying to this modbox in thread will be off topic  Posted By: Cuddles

Yet quoting text from posts removed eight hours before a response is made allowed to stand ? I see.

I'll assume all off-topic posts will be dilligently moved out of the thread from now on then. Crikey, that's probably a lot of work for you, given the thread history.

 

[Major_Tom]

___

YOU claimed that the analyses in BZ & BV were fundamentally different.

I disagreed & invited you to explain yourself.

You refused to reply

Tom, you seem to be the only person left posting that believes this crap.

Can you explain why you disagree?

 

[Major_Tom]

Sorry Oz,

Major Tom claimed that he could explain all this to you.

But when invited to do so, he goes silent.

If you expect him to "put you right", you're gonna be sorely disappointed.
___
___

Major Tom,

Why are you leaving Oz hanging?

Why have you not replied to my invitation to explain your "understanding" of the difference between BZ & BV?

You've stated repeatedly, sarcastically, (& comically) that BV's "crush down - crush up" theory is wrong, ludicrous, a joke. You state that Bazant has made "simple errors".

Why haven't you explained BV's crush up & crush down "simple errors"?

You claim that Bazant's equations 12 & 17 in BV "cannot be applied to the WTC towers" & "have been debunked long ago".

Please explain why they cannot be applied to the TTs.
And provide your debunking.

The phrase "put up or shut up" comes to mind…

tk

PS. You claimed that Ryan Mackey's statements about the precision & usefulness of models was "all BS and a lie".

I asked you here to elaborate on exactly which statements were "BS & a lie".

Thus far, lots of insulting accusations, and zero explanations.

Typical...

Yes. Tom, the concept of crush down, then crush up is explained in detail in BV, BL and BLGB.

Tom, do you believe in the concept of crush down, then crush up?

Please explain to us little people why Bazant is correct when he claims that significant crush up is impossible before crush down is complete.

Is he wrong? Why or why not?

 

[newton3376]

W1 and W2 are defined to be equal. Quite different to setting them equal, yes ?

Why don't W1 and W2 appear in Fig 4.c ?

You didn't answer the questions any more then MT did.

And you made the SAME mistake claiming W1 doesn't appear in Fig 4.c...

Sigh.

 

[newton3376]

(...my emphasis added.)
Let's not forget that a large part of the concerns with Bazant's papers is whether or not the findings apply to WTC Twin Towers collapse.

Which, of course, requires careful consideration of what you dismiss with the word "whatever". What does Bazant consider was "crushed" at WTC as distinct from what he includes as "crushed" in his objective of developing a more generic model.

I think you missed the point....

Analyzing the graph mathematically as a general calculation of simple areas is a bit different from going into the physical interpretations of how that calculation applies to specific cases.....

It doesn't matter if this was a graph from the WTC or not....the way you would calculate the work done using that graph is the same.

If you guys can't get the math right, what makes you think you understand the physics interpretation of the math/graphs?

 

[Major_Tom]

My mistake is fixable upon edit or in the next post.

Not the good Dr's.

No amount of patchwork can save BV, BL and BLGB.

The regular posters here can be expected to hide from this fact for a few more months.

It took about 8 months for some posters to learn to distinguish between BZ and BV. R Mackey had his break-through just a week ago, in this very thread.

TFK still hasn't, as his quoted posts reveal.

 

[Major_Tom]

uh, no. If worthless, why would they bother to publish it? Why would reviewers and editors accept and publish it?

The assumptions are called "simplifying assumptions" and not "worthlessing assumptions" because they simplify the problem -- in this case, as in Dr. Bazant's other works on the subject, providing a bounding envelope of likely outcomes. This result is not precise, but it's hardly worthless. Those assumptions are not guesses about what actually happened. They describe the model that the researchers applied to the problem.

All of science uses models. All of it. And some models are better than others. Some models only apply in certain situations and require some care before relying on them. If we took such a hardline, black-or-white view as you did, there would be no such thing as science. Nothing is 100% precise. Everything, every prediction, every estimation, every calculation relies upon sampling and assumptions and simplifications. Some fields like economics are so abstracted it's sometimes hard to even draw similarity between the simplifications and reality.

The only way the Bazant & Verdure model and result are "worthless" is if there exists a plausible case that lies outside its bounding envelope. Well, we're still waiting for such a solution.

I understand enik might claim he has one, but like the Great Oz he keeps it well hidden, behind a curtain. This is silly. If anyone has such a result, it should be examined, verified, and published, at the very least in a conference setting.

None of this has happened. Ergo, there is no validity to claims that Bazant & Verdure is worthless. QED.

---

For the tl;dr crowd: The quoted poster knows precisely zip about science.

A quote from R Mackey, just a short time ago. The quote is pure bunk, but few of you noticed. Why bunk? Because this is the mutant frankenstein theory invented on JREF. He totally misinterprets BV, BL and BLGB. Just like the last few years.

Few if any of you noticed that you invented your own theory here on JREF, and through intense group-think, most every poster began to believe it. (And spray hatred at those who don't).

He suddenly changed his mind a few posts later.

I'm still waiting to ask him what cause the change of heart?

 

[TruthersLie]

My mistake is fixable upon edit or in the next post.

Not the good Dr's.

No amount of patchwork can save BV, BL and BLGB.

The regular posters here can be expected to hide from this fact for a few more months.

It took about 8 months for some posters to learn to distinguish between BZ and BV. R Mackey had his break-through just a week ago, in this very thread.

TFK still hasn't, as his quoted posts reveal.

So from your words here, we can expect that in the "next few months" you will have submitted your critique to Dr. Bazant, JEM, or ASCE?

When will you be doing this?

 

[twinstead]

"Some dudes" on the interwebz complaining about how Bazant is worthless impresses me NOT.

 

[W.D.Clinger]

Kibbitz away.

Okay. First, an apology...

Bonus questions for ya, MT.

In the diagrams, Bazant indicates the values of:
Fc, F0, ∆Fd, ∆Fa, W1, W2, λh, zc, h, K & mg.
One of these is incorrectly identified in the graphs? Which one?

You should assume I know at least two different ways to answer that question. I apologize for the coyness of what follows; I'm trying not to give those answers away.

But you have an error, too, tfk. Very fundamental. You say

- W1 is associated with the portion of the fall when the upper block decelerates.
- W2 is associated with the portion of the collapse when the upper block accelerates.

This is incorrect. Note the block accelerates while still in the W1 region in 4a, and it also accelerates while in W2 region in 4b, therefore the association you claim is false.

The block decelerates whenever F(z)> mg.
It accelerates whenever F(z)<mg.

Here I agree with both Major_Tom and with you. Your original comment struck me as incorrect, so I agree with Major_Tom, but the last two sentences of the above are correct, so I also have to agree with you about that part.

I asked you which of the values described on Bazant's graphs was incorrectly marked. No answer...?

Bažant and Verdure's paper contains several errors, including that one. In reading that paper, we all have to figure out how we're supposed to correct those errors. In general, there will be several different ways to correct an error. Which correction is best is somewhat subjective, because it involves a guess concerning the intentions of the authors.

You have identified an error, but I think you guessed wrong about the authors' intent and are attempting to repair the error in a way that will require several other corrections to the paper. I think Major_Tom's view of W1 and W2 is more likely to be what the authors intended, and that the error you found should be repaired in a way that does not associate W1 with deceleration and W2 with acceleration.

This may be related to the labelling of the x-axes in figures 3 and 4. Excepting the bottom row of figure 4, Bažant and Verdure label the x-axis with u and h, not z. According to the first column of page 311, they treat z as a constant.

All of the technical errors (as opposed to modelling errors) I have found in that paper are consistent with the hypothesis that its two authors used slightly different notational conventions and failed to reconcile those conventions fully; some of the responsibility for that may lie with the reviewers and editor, who may have overlooked those errors or requested some last-minute changes without checking the results. That sloppiness makes the paper harder to read, especially for non-engineers such as myself and Major_Tom, which may explain some aspects of this thread.

 

[triforcharity]

My mistake is fixable upon edit or in the next post.

Not the good Dr's.

No amount of patchwork can save BV, BL and BLGB.

The regular posters here can be expected to hide from this fact for a few more months.

It took about 8 months for some posters to learn to distinguish between BZ and BV. R Mackey had his break-through just a week ago, in this very thread.

TFK still hasn't, as his quoted posts reveal.

Have you submitted your discussions to the journals that these papers appear in?

If no, why not?

 

[tsig]

A little too late for that, Ozeco, but consider #2 on his second list: Smiling.

I'm actually smiling right now.

I'll be smiling pretty much the whole time as I assemble a final collection of arguments against BV, BL and BLGB.


I have literally thousands of posts with the JREF forum that botch the Bazant papers so badly that the Author himself wouldn't recognize your Frankenstein hybrid misrepresentation as being in any way related to his writings.


Open mouth, insert foot...that sort of thing.




Anyway, I'll leave some time for R Mackey to respond.

Are you mistaking the JREF for some sort of peer review organization?

 

[Carll68]

In the bigger picture, can someone explain why this minutia being discussed matters? I mean, what difference does it really make if any of Bazants papers have incorrect formulas?

 

[tfk]

It took about 8 months for some posters to learn to distinguish between BZ and BV. R Mackey had his break-through just a week ago, in this very thread.

TFK still hasn't, as his quoted posts reveal.

You speak for Major Tom.

I'll speak for tfk.

You're not qualified.

Your delusion that you have brought enlightenment & the reversal of stances on BZ & BV's papers to Ryan or to the rank & file posters here is a PERFECT metric of how reliable are your assertions on any of these topics.

 

[Major_Tom]

Tom, posts 1327 and 1328 have questions for you.

Let's see if you can answer them without falling on your face.