Szamboti's Missing Jolt paper

[ozeco41]

Whilst I have few issues with the Bazantian limiting case during progression (within its scope of applicability, namely energetics only), I think it should be highlighted that the initial state was pretty unreasonable.

NO-ONE^* would expect arrest when dropping the entire intact upper section through large distance (x) onto intact structure below.

That specific issue could be massaged by providing the minimum distance (x) that would still result in progression...

And as I am sure you recognise it's a lot more complicated that simply providing a distance X^min.

The Bazant cases presumes a form of homogeneity in the dropping bit and the lower tower with or without a rubble layer interposed. They don't distinguish floors/perimeter/core.

The reality is that collapse progression ("global collapse") occurred as three distinct and related mechanisms ("ROOSD"; perimeter peel off and core strip down)

Somehow whatever the mechanism of collapse initiation was it then led into a transition stage in turn leading into established progression involving those three mechanisms.

I could not dare to even attempt to define how that transition worked and that transition would define X^min.

...I'm not sure if David Benson ever actually provided that value...

..I'm not familiar with his work. Did he take the Bazantian assumption of what I called "homogeneity" OR did he allow for transition into the three components of the global collapse? If he did he would be one of few at most. I don't know of anyone who has attempted to quantify those realities.

 

[beachnut]

No. How many readers or reviewers have the knowledge of the visual record required to properly review Bazant's claim in BLGB that his model matches all observables?

Checking such a claim requires a good understanding of what those observables are.

911 truth can't do the math, they can't comprehend models, so they attack knowledge. 911 truth should have gone to engineering school, 911 truth keeps proving they are knowledge free in engineering and models. Was the math what tripped 911 truth up, the differential equations? 911 truth is funny, 10 years and they could have earned a degree, no a PhD in structural engineering to understand the gravity collapse was not an illusion, and that "the gravity collapse was an illusion", was their delusion as they hunt for the evil guys, the Satan like guys in their fantasy version of 911.

... you are attacking things you don't understand, instead of setting goals and stating conclusions for you own work filled with nonsense.
...

To me, sitting on top of these images for years without doing anything with them is criminal. There was never a mystery as to the progression mechanism, just a bunch of hidden photographs I had no access to.

Nonsense. Why does Bazant not have silly crap in his paper. No wonder your math free work goes unpublished. Even Heiwa got published and his delusional work was total nonsense. And what was your great conclusion? Or is it criminal you never state a conclusion, never set a goal, never say anything that means anything. Why have you failed to publish a rebuttal paper to the work you attack? Good luck

Are you supporting the real cd deal, or not? Make a commitment after 10 years? Does tony's work support your claim unknown evil Satan like guys did 911 and not 19 terrorists? Does tony's work prove the gravity collapse is an illusion?

 

[ozeco41]

MT, do you reckon that ergo discusses engineering [etc] competently than, say, ozeco, BasqueArch, Newtons Bit, tfk;...

That's quite a broad group there Oystein.

...It appears as if you try to avoid criticising or slapping ergo at all costs. Is that because you regard his competence highly?

It's an artefact of M_T's own approach to WTC Collapse and which parties are Right OR Wrong. There is no grey area; no distinction between "big picture" and details in M_T's approach. Only his way which is "right" and all the rest which are wrong. Fully wrong. Totally wrong. Not even right on the big picture wrong in a bit of detail. Ergo gets sort of conditional benefit of the doubt because he runs takes an occasional step or two against the tide

...I know - I've tried several times to explore the issue with M_T and we have never progressed it.

...and copped occasional flack for daring to support a "truther"

 

[Major_Tom]

And as I am sure you recognise it's a lot more complicated that simply providing a distance X^min.

The Bazant cases presumes a form of homogeneity in the dropping bit and the lower tower with or without a rubble layer interposed. They don't distinguish floors/perimeter/core.

The reality is that collapse progression ("global collapse") occurred as three distinct and related mechanisms ("ROOSD"; perimeter peel off and core strip down)

Which is a distinctly non-homogeneous process. Exactly.

..I'm not familiar with his work. Did he take the Bazantian assumption of what I called "homogeneity" OR did he allow for transition into the three components of the global collapse? If he did he would be one of few at most. I don't know of anyone who has attempted to quantify those realities.

In BLGB, he is the second "B". Bazant, Le, Greening, Benson. He was a blockhead, but I believe he has modified his position.

Correction on Benson: He was in agreement with others including myself at the 9/11 Forum as early as July, 2008, as the first page of the linked thread shows:
http://the911forum.freeforums.org/p...-twin-towers-and-collapse-mechanisms-t62.html

He had a small "relaps" later in the thread but both "G" and the second "B" from BLGB were in agreement with the ROOSD concept as early as July, 2008.

That just leaves Bazant and his graduate student Le in agreement with the gist of his own paper, BLGB.

The other "G" and "B" peeled off to the ROOSD concept early on.

 

[pgimeno]

Source? Where are the photos of this?

Prominent example:
http://whywtc7fell.info/misinfo/aeppt97/059.html
Another example:
http://www.stevespak.com/fires/manhattan/wtc6.html
Check the second photo. And the third. And the last. Credit goes to TruthersLie for this post in which he mentions iron workers talking about 14 floors pancaked on top of each other: http://www.internationalskeptics.com/forums/showpost.php?p=5192820&postcount=9
Still far off topic.

That's from a different paper (Bazant 2007) to that which NIST discusses (Bazant 2002), and is therefore not «officially endorsed». Fail again.

It's from "What DID and DID NOT Cause Collapse of WTC Twin Towers.." (BLGB) first published in 2007. Revised three times after that.

I'm well aware of that. Still not «official».

 

[ozeco41]

Which is a distinctly non-homogeneous process. Exactly....

Spot on. It isn't simple. The attempts at analyses from my perspective fall into two camps:
1) Those that want to take the mathematical path and therefore, of necessity, make simplifying assumptions. Those simplifying assumptions then serve as a source of confusion to us of the masses discussing on the Internet. (Setting aside whether "They" confuse themselves. )

2) Those like me who prefer to analyse the actually mechanisms which really happened. The necessity down that path being that it is too complicated and you cannot define most of the mechanisms sufficiently to let you put mathematical "proof" onto it.

The exception being Twin Towers global collapse stage where, as I have said many times, all the energies and forces are "overwhelming" so the maths doesn't need to be precise.

In BLGB, he is the second "B". Bazant, Le, Greening, Benson.

...yes but I thought femr2 could have been referring to other independent work by DB.

 

[Major_Tom]

I have been an "equal opportunity" critic of both yourselves, STJ911 and AE911T.

Little doubt about that since my first posts, for which I was booted from their forum. Both imaginary sides live under false claims and censorship of anything outside the STJ911, AE911T, NIST, JREF, Bazant nexus. Both sides depend on false data.

I think they all feed the general public a piece of $#@&. Have I been unclear about that?

 

[femr2]

And as I am sure you recognise it's a lot more complicated that simply providing a distance X^min.

Sure, especially given it's all 1D, but the value can be useful (for me) in a number of ways. Translating it into a velocity-based value not the least-useful.

Somehow whatever the mechanism of collapse initiation was it then led into a transition stage in turn leading into established progression involving those three mechanisms.

It is that "transition" stage which is skipped between the end-point of NIST and start-point of Bazant that I'm looking at in this instance.

Basically, I'd be more interested in impact velocity rather than the actual drop distance.

A freefall drop of the entire upper section, treated as a single 1D mass, results in an impact velocity.

I'd like to know the minimum velocity that still results in the 1D progression.

..I'm not familiar with his work.

You probably are. He's the other "B" in BLGB. (ETA: I see you are aware) Member of the911forum but hasn't posted in a while.

He has performed a number of example calcs there, as he had a "functional" bazant/BLGB model to play with. Not quite independant work, but a useful insight into BLGB for sure. He's the only person I am/have been in contact with that is in a position to "run" the full BLGB model with variation in the initial state.

 

[beachnut]

...
I think they all feed the general public a piece of $#@&. Have I been unclear about that?

For the rational side you attack, yes, you are clear, you don't do math and engineering.

 

[pgimeno]

A freefall drop of the entire upper section, treated as a single 1D mass, results in an impact velocity.

I'd like to know the minimum velocity that still results in the 1D progression.

Just to be sure, are we still talking about the 1D model of axial column-to-column impacts?

 

[femr2]

Just to be sure, are we still talking about the 1D model of axial column-to-column impacts?

Bazant and co...

 

[ozeco41]

Sure, especially given it's all 1D, but the value can be useful (for me) in a number of ways. Translating it into a velocity-based value not the least-useful....

I comprehend where velocity would fit against your measurement work.

...A freefall drop of the entire upper section, treated as a single 1D mass, results in an impact velocity....

Hence my distinction into the two approaches. There was no free fall in the real collapse ("Missing Jolt" notwithstanding. ) So the "impact velocity" is a theoretical construct from a simplified model. At this stage I cannot see how that interfaces with actual collapse measurements.

...I'd like to know the minimum velocity that still results in the 1D progression....

See previous comment.

...He has performed a number of example calcs there, as he had a "functional" bazant/BLGB model to play with. Not quite independant work, but a useful insight into BLGB for sure. He's the only person I am/have been in contact with that is in a position to "run" the full BLGB model with variation in the initial state.

Gotcha - thanks. I have no immediate interest - could become important to me if discussion here heads off the rails into confusion land and I have to put brain in gear to contribute. (I'm still running in "coast mode" at 0330 local time on Sept 11th)

 

[femr2]

At this stage I cannot see how that interfaces with actual collapse measurements.

It doesn't. But it would be interesting to see how much 'headroom' there is in a 12ft freefall initial state. How little would still result in progression ? Would 6ft arrest ? 1ft ? 1 inch ?

 

[tfk]

...
He had a small "relaps" later in the thread but both "G" and the second "B" from BLGB were in agreement with the ROOSD concept as early as July, 2008.

That just leaves Bazant and his graduate student Le in agreement with the gist of his own paper, BLGB.

The other "G" and "B" peeled off to the ROOSD concept early on.

Please link to where Greening & Benson say - in their own words, not your interpretation of their words - that they rescind their support of the BLGB paper.

What do Benson & Greening assert now regarding "controlled demolition" vs. "collapsed due to damage from jet impact & subsequent fire"?

Now this result split the subsequent JREF debate into two camps. One side was led by the usual JREF nay-sayers who declared, (without proof), the model does not represent the Twin Towers in any way shape or form. On the other side was the lone voice of Hiewa, an oil-rig engineer, who avidly defended the model and its ability to resist progressive collapse. The gist of Heiwa’s argument was that the details of Dr. Sauer’s model, or indeed any model, are irrelevant to any tests of Bazant’s crush-down hypothesis because a smaller upper block can never crush a larger lower block as long as they are made of the same materials and have the same basic structure. This being the case for WTC 1 & 2, or so Heiwa claims, means that it is physically impossible for the upper blocks of WTC 1 or 2 to destroy the lower (larger) sections of the towers without first destroying themselves! Now this got me thinking about models and collapse mechanisms for WTC 1 & 2 and I thought a thread on this interesting topic would be useful over here on The911Forums.

Where I would disagree with Heiwa is that the structural details of a meaningful physical model of the Towers are not just important, they are crucial!

My conclusions from this passage:

1. It must cheese Dr. G off no end that the folks that he disdainfully dismissed as "the usual JREF nay-sayers" ended up being right about just about every single substantive argument. And more importantly, right about the ultimate conclusion: the analysis by NIST was done honestly & competently, NIST's conclusions (damage & fire caused the collapse) have been borne out and accepted by the engineering community as correct, AND there is precisely zero evidence (that holds up to the slightest scrutiny) of any controlled demolition.

And the JREF nay-sayers were right for one specific reason: they listened to the opinions of experts. Not blindly, not uncritically. They asked questions, challenged things that didn't seem right (at first blush) but listened to the experts follow-up explanations.

2. I can't say anything about how familiar Greening was (at that time) with Heiwa's claptrap. He seems to show some skepticism ("... or so Heiwa claims ..."). But not the level of "that's just plain wrong" that would be appropriate of someone with a knowledge of structures & mechanics.

I'd be curious what Dr. Greening thinks about Heiwa's claptrap today.

Any linky's, MT?

 

[ozeco41]

Which is a distinctly non-homogeneous process. Exactly.
In BLGB, he is the second "B". Bazant, Le, Greening, Benson....

Hey M_T the thread was moving too fast. You edited the post after my earlier comment and I think you added the following additional info:

...He was a blockhead, but I believe he has modified his position.

I disagree with your labelling "blockhead" as being unnecessarily denigratory. If you mean a supporter of a Heiwa style rigid block interpretation why not say so? If you don't the label is simply personal insult.

...Correction on Benson: He was in agreement with others including myself at the 9/11 Forum as early as July, 2008, as the first page of the linked thread shows:
http://the911forum.freeforums.org/p...-twin-towers-and-collapse-mechanisms-t62.html

He had a small "relaps" later in the thread but both "G" and the second "B" from BLGB were in agreement with the ROOSD concept as early as July, 2008.

That just leaves Bazant and his graduate student Le in agreement with the gist of his own paper, BLGB.

The other "G" and "B" peeled off to the ROOSD concept early on.

If they switched to the concept which you label "ROOSD" July 2008 they were only 7 months behind me. I may follow up if I need the info.

 

[ozeco41]

It doesn't. But it would be interesting to see how much 'headroom' there is in a 12ft freefall initial state. How little would still result in progression ? Would 6ft arrest ? 1ft ? 1 inch ?

I don't think it helps. It is still an artificial scenario.

I would rather by far "know" how the cascading failure and load redistributions of the initial collapse allowed the top block to start to descend without the interposing of any free fall state. I regard the "free fall" as an artefact of a theoretical and oversimplified model #.

So from my perspective why push an oversimplified model into territory which is probably beyond its applicability. Granted I doubt anyone could ever quantify the real what actually happened complexity of the collapse initiation.


# Free fall of the whole block I mean. I would not be surprised if there were small bits of individual members falling at around "G" in the mess of initiation - similar to WTC7 but at micro scale - not worth pursuing though - I'm just covering the possibility.

 

[ozeco41]

...My conclusions from this passage:

"from this passage"????

BUT with a large dose of extrapolation and scope of claim extension.

 

[tfk]

MT, do you really believe engineers even read (past tense) BLGB … ?

No.

Wrong.

I did.

I've seen several other mechanical & structural engineers, (as well as several mathematicians & scientists) who have read BLGB, understand its approach, its assumptions, its simplifications & its conclusions, and agree with it.

I've also seen lots of truthers like you two, who don't seem to possess a clue how to interpret the meaning or the math in the papers, yet claim that it must be wrong.

… somehow.

… in some unstateable fashion.

MT, do you really believe engineers … support crush down, crush up?

I do.

I'm not really convinced that either of you understand the boundaries of the concept.

Either of you care to write down your understanding of what it really means.

Why would they?

Something to do with "being correct", perhaps...

How many readers or reviewers have the knowledge of the visual record required to properly review Bazant's claim in BLGB that his model matches all observables?

Care to state where BLBG makes this claim? (Without excising a comment from its context, of course.)

Care to explain why, if BLBG states that his model "matches all observations" (as you assert), he explicitly states the following:

For the duration of video record, the foregoing equations give the correction of height due to tilt, which attains 0.48 m at 2 seconds (the video record actually extends up to 4 s, at which time, according to NIST, the tilt angle to the East was 25◦ and to the South probably remained small). Thus the tilt after 2 s is too high for comparing the present one-dimensional model to the video, although this model appears adequate for the overall collapse.

Still think that Bazant thinks that his model "matches all observations"?

Checking such a claim requires a good understanding of what those observables are.

Nope.

Checking Bazant's claims (& math) requires an understanding of structural mechanics, in order to first understand which variables are important to his analysis, and which variables are irrelevant.

The structural mechanics & the math are the pieces of the puzzle that you, and femr, lack.

AFTER you understand which variables are significant, THEN you can go to videos or engineering references to verify that you're using appropriate values for that subset of variables.

The flip side of this coin is that there are 10,000 variables that are totally irrelevant to his methods & his math.

These irrelevancies seem to be the specific variables (& observations) that you truthers are hung up on.

 

[tfk]

"from this passage"????

BUT with a large dose of extrapolation and scope of claim extension. http://conleys.com.au/smilies/naughty.gif

Yup.

I think I explained my two provisional conclusions fairly clearly.

Which do you think are unjustified & why.

 

[Myriad]

It doesn't. But it would be interesting to see how much 'headroom' there is in a 12ft freefall initial state. How little would still result in progression ? Would 6ft arrest ? 1ft ? 1 inch ?

You don't need any initial freefall state. You just need the downward velocity to stay above zero.

If the upper mass descends at less than free fall, that means the potential energy, instead of all being converted into kinetic energy, is doing work on whatever elements of the structure are causing the resistance. Doing work is doing damage.

So, it's quite feasible for the first story of fall to be well below free fall and encountering a lot of resistance the entire way -- but by the same token, when it finishes falling one floor's distance, the damage done to cause that resistance means there's no longer a "still intact" floor below for it to collide with.

From the start, that's a more likely scenario than meters of free fall followed by one big sudden collision, due to the nature of the perimeter and core columns, for which multi-story buckling is more likely than three-hinge buckling within a single floor. For the floor areas, a typical office cubicle layout would leave some room for unresisted falling, except that (1) any tall strong structures like server racks or banks of filing cabinets could start transferring momentum to the floor below well before the upper floor falls the full distance, and (2) if we're talking about the very first story of descent, the columns and floors are still at least partially connected together at that point.

There is an implicit assumption in the above, that the work/damage to the structure that slows the fall is all occurring in the top of the lower section. But that actually doesn't matter; if the damage were to the bottom of the upper section during the first story of descent, that would have exactly the same effect in terms of rendering a solid collision between "intact" floors (let alone an impact that transfers enough momentum to arrest the collapse) impossible.

An unresisted free fall followed by a big crash that crushes "the next" floor is merely a simpler model to think about and calculate. The integral of the resisting force through a story of fall -- that is, the work done on the structure to damage it during one story of collapse -- works out the same either way.

Respectfully,
Myriad