Szamboti's Missing Jolt paper

[Newtons Bit]

Your Freudian slip is showing

Whoopsie.

Still true though. I read his posts, had a laugh, and then went back to my life. There was absolutely no compulsion to respond to his commonly told lies.

 

[tfk]

that is bent into an arc thru that array.

Prior to tilting? 0.1sec in the collapse? No way!

achim, please.

I can only hope that you are merely PLAYING obtuse, and not REALLY this obtuse. Otherwise, this conversation is going to be over very quickly.

We are modeling the core columns from just (say 1 - 10 seconds) before the collapse initiation.

The tilting began just as soon as the towers stopped swaying, about 2 minutes after the jet impact. They settled into a tilted configuration. Oh, it may have been minor & difficult to measure from the crude videos of the external wall. But I guarantee you that the columns were facing a new, bending moment that they'd never felt before & never been designed to withstand. And that bending loads (and the arc into which it bent the core columns) grew continuously until it was extreme, just before the moment of collapse.

The top of both towers were bent tilted thru the collapse floors. The amount of flex in those columns just before collapse was extreme. The state of stress can be imagined by combining a thick (about 200' for the outer columns, about 70' thick for the core column) beam in flex (compression on the inner fiber, tension on the outer, zero at the neutral axis), PLUS a distributed, compressive gravity load. With the gravity load carried mostly by the outer columns, due to the core shrinkage.

So, 1 to 10 seconds before the collapse initiation, yes, the columns were bent into severe arcs.

So there were 3 states for the columns:
1. damaged or buckled to the point that they carried minimal or no load.
2. inelastic (not kink) buckled columns still carrying a fraction of their unbuckled loads, like the south wall on WTC1 (which buckled at about 100 minutes)
3. unbuckled columns, some of which (by definition of the impending global collapse that is a couple seconds away) are bent to the very edge of either buckling or connection failure.

Now, it is trivially easy to imagine a single column bent like this. However, bending an array of columns, while attempting to keep their lengths unchanging, is a completely different matter.

If you actually attempt to build such a model (with pencil & paper, 3D computer visualization programs or just using the Mach 1 brain with which you may have been born), instead issuing useless smart-azz one-liners, THEN you might begin to appreciate the problem.

femr is modeling this with straight, unchanging, undeformed lengths.

Yes, with a little fantasy you can imagine what has to be done. Ik chains etc. are a lot of work. That model is still a baby. Come back when it's done.

Trust me. Of the three of us (you, me & femr), ONE of us has a very good idea of "what has to be done". And from my seat, only one of us...

I'll be sure to look in when he's done. Would you care to place a wager of German beer against American beer that the objections that I've raised from the start end up debilitating his model to te point of near-uselessness? The matter to be judged by an impartial Professional Structural Engineer, of course.

Do you deny the existence of the inward bowing?

Noop and you know it. 3m sagging in 20 min of fire is nonsense anyway.

We just met, achim. I don't know much of anything about you. I will ask you what you think, not tell you. I request you do me the same courtesy.

BTW, the American slang is "Nope".

it does not matter one iota what was causing that bowing.

If so then it doesn't matter who the terrorists are.

Here is my sentence. Verbatim.

If [the bowing exists], then in a very real mechanical sense, (i.e., to the load carrying capacity of the columns), it does not matter one iota what was causing that bowing.

"... in a very real MECHANICAL sense ..."
"... to the LOAD CARRYING CAPACITY of the columns ..."

Perhaps your English is not quite as good as I first thought.

The columns have no politics. They will buckle at exactly the same side load no matter who, or what, is pulling them to the side. Please read my comment again.

"... no matter what is causing that bowing ..." means "sagging floors", or "buckled core columns", or "all the furniture sliding to the low point of the sag"...

It does not mean "George Bush" or "Osama bin Laden".

One thing that is 100% certain, there is precisely zero way for explosives or thermite to cause a bow that develops gradually over the course of 20 minutes.

Perhaps, to demonstrate that you have read what NIST really said, and are not just repeating hear-say, you should come back here with the excerpt from the NIST report where they explain WHY they feel that they could not get that amount of inward bowing from the floor sag.

It doesn't matter one iota what they feel.

Allow me to reiterate:

"Perhaps, to demonstrate that you have read what NIST really said, and are not just repeating hear-say, you should come back here with the excerpt from the NIST report where they explain WHY they feel that they could not get that amount of inward bowing from the floor sag."

I didn't address whether or not you think it matters what they say. I would like to first demonstrate that you in fact KNOW what they say.

Can you give me ONE valid, supportable reason that you feel entitled to smear the reputations of these extraordinarily accomplished people?

Logic.

Ahhh, I see.

One word. Zero context. Zero substantiation.

An argument worthy of any 13 year old, achim. You would do well to try much harder than this if you wish me to continue to converse with you.

By the way, I also asked you to answer the following question. Please do so, so that I have some gage with which to calibrate your personal concept of "logic".

So that I understand the qualifications that you possess to make that judgment, would you be so kind as to reveal your engineering background & years of experience.

Please give me a generic answer to this question.

BEACHNUT[/B]]
While NAZI Germany was persecuting Jews and driving out the best minds in their country ...

Let's get it right. Nazi Germany supported by Grandpa Bush. That's what you are talking about. Are you talking about the immigrated scientist prior to the war or about the Nazi scientists the CIA took to USA e.g. to Fort Dettrick (source of Antrax for Irak for example)?

Just in case you missed it, that was beachnut's post.

It's easy to tell us apart. Of the two, I am the blushing schoolgirl with the oh-so-farkin'-delicate sensibilities...

I wouldn't pull the NAZI card on someone from Germany, unless they did something like, oh, I don't know, pull out that old, utterly debunked "George Bush's grandfather bankrolled Hitler" crappola.

... Nazi Germany supported by Grandpa Bush ...

Well, hot damn. Will you lookee there...

Tom

 

[ElMondoHummus]

The tilting began just as soon as the towers stopped swaying, about 2 minutes after the jet impact. They settled into a tilted configuration. Oh, it may have been minor & difficult to measure from the crude videos of the external wall. But I guarantee you that the columns were facing a new, bending moment that they'd never felt before & never been designed to withstand. And that bending loads (and the arc into which it bent the core columns) grew continuously until it was extreme, just before the moment of collapse.

Just a further note for newer folk who may be reading this: Tom can indeed guarantee the stress on the columns because it's true even if you posit controlled demolitions. If the columns were not pulled out of alignment, and also not severely flexed, then the jets impacts, the fireballs, and the subsequent fires were faked because all of those would've caused the very stresses Tom is talking about here.
Simply put:

• If the jets actually crashed, but everything after that was "Inside Job", then many columns are still misaligned as well as badly stressed because the jets severed some columns, thus resulting in load transfer to the surviving, intact ones.
• If the jets were faked, but the noted fireballs were actually demolitions, then many columns were still stressed. The explosion clearly severed perimeter columns (you can even see that in pictures) and the loss of those columns would cause stress on both other perimeter plus many interior ones. That stress would result in a flex that would cause misalignment.
• If the jets and the fireballs were both fakes, but the fires were deliberately set, then you may have an argument if the fire resistant material on the steel was enough to hold off thermal creep before the supposed demolitions went off. Otherwise, you still have stress that could lead to misalignments, depending on the amount of creep. Yes, the Arup engineering firm did indeed posit that such thermal creep could occur even with SFRM intact on the steel, so this is not an unimaginable scenario.
• If the jets and the fireballs and the fires were all faked, only then do you have an argument that the columns could not have been stressed and misaligned at all. Problem is, you're a no-planer well before this point and have amply demonstrated your ignorance of the majority of the evidence.

Tom is right about his guarantee in all cases except where everything - the collisions, the fireballs, and the fires - were faked. And if that's the argument someone wants to make in response, then good luck trying to prove it. Not a single no-planer has been able to make his points fly; every single argument positing that has fallen flat on its face 2 inches from takeoff. So, everyone can accept that the flexing and stresses were there. Or, someone can resurrect the no-plane arguments yet again and force us to link posts from the archive for the umpteenth time.

Just noting this, in case someone wanted to try to challenge the notion that the columns could not have gotten experienced the stresses and subsequent misalignment.

 

[Newtons Bit]

I'm amused that some people think the towers can be modeled with IK chains (which are nothing more than animator tools) more accurately than with 3d finite elements.

 

[femr2]

I'm amused that some people think the towers can be modeled with IK chains (which are nothing more than animator tools) more accurately than with 3d finite elements.

And so you should. There has been no suggestion of anything of the kind, simply (and repeatedly) that it'll be used to visualise various scenarios, which at the moment are described using static 2D stick models. Visualise only. Not simulate, in the slightest. In essence it's a 3D stick model, a point repeatedly made clear.

Will conclusions be drawn from the model itself ? Not directly as far as I'm concerned. It will be used as a visualisation aid. Helpful, for me at least, to get a reasonable 3D view of what implications may result from looking at initiation in different ways.

To give an example: There's currently an animation which shows column overlap resulting from a 3 degree initial tilt. Is anyone *in their right mind* going to turn around and point out that columns are not going to intersect like that in the real world ? One would have hoped not, but hey.

In the context of this particular thread, for me, what it showed (in it's utterly infant form) was that for a 3 degree tilt, the distance between the 99th and 98th floor on the south edge was probably pretty small, and that any subsequent vertical drop would involve a pretty continuous series of impacts between the floors themselves, followed by the 1000 series columns (to a certain extent, without getting into the whole column alignment malarky), followed by the core bracing, followed by the 900 series columns, followed by...

Pretty simple observations in my book, fairly obvious, but useful to be able to see it.

Result ? Lots of smaller magnitude *jolts* over a period of time. Once the angles are worked out a bit more accurately, might even go so far as to estimate a period of time for that series of sequential impacts. Useful ? Maybe. Have I stated that before ? Nope. The model is still being built, and the initial tilt and vertical drop data needs to be a lot better to really say such, but just wanted to try and put things into a bit of perspective here.

Now, regardless of who may have made assumptions, misunderstood context, purpose or scope, the bottom line is it's a visualisation aid (feels like I should repeat that as often as I can), and that it's unlikely that any conclusions will be drawn from use of it in itself. Perhaps rigging a scenario, getting a feel for some of the less obvious spatial implications, staring into space for a while and THEN making some conclusions based on a bit of spatial context info it might help us to see, sure. Nowt wrong with that.

Suggest folk take care to not get too carried away within their own particular trains of thought.

 

[Baylor]

Oh dear, you're back.

 

[achimspok]

Perfect summary of your engineering skills; commenting on junk about Chicago. Instead of presenting college credentials, or supporting Tony, or digging up engineering precepts to support your position (whatever it is, but you can't explain), you jump on bashing Bush which is cute, but exposes a propensity to spew moronic conspiracy theories based on political bias.

Oops, did anyone of you present any skills? Noop.
Nothing but smugness. Pages and pages and pages.
Oh well, I was here a while ago. I thought it would be nice to discuss this topic.
There was no discussion. Now it's page 35. I think back then it was 5 or 6 or something like that. It doesn't matter. There was ZERO discussion about that topic. It was the ver same ****ING babble that is going on right now.

Edited by Tricky: 

Edited for rule 10. Profanities must be completely masked in public section.

"Ah, Germany is known for..." "You said Chicago first." "Achim must be 13."

What tfk going on here? Engineering? Can't find anything like that.
Well, I told Tony what I think in a personal message.
Isn't your style here, right?

Crappola, Tom? Or should I write "ol daddyo" to do it in your style.

Perhaps, to demonstrate that you have read what NIST really said

It's BLA BLA, Tom! You have proven that you know near to zero about the collapses.
All you have repeated was a completely wrong NOVA animation.
If you really (or anyone here) would have the engineering experience you coquet with THEN ... Oh, I don't know. That NIST animation is such a crap that you probably immediately would have lost your last white hair and 40pounds of weight. However.

Catenary forces, Tom? (Just north south?) 55 inches inwards? 20 minutes after the first window broke due to surface temperature? No, don't try to make any sense of it.
It doesn't matter at all right?
Shear forces, Tom? ...shearing the perimeter columns above and below the spandrels but the floor connections didn't fail? Oh, i forgot it doesn't matter.
Someone here described how the damaged tower had to distribute all loads to the south because of the damage in the north and therefore the tower HAD TO bow and collapse in the south. Well, the south tower did simply the wrong thing, right?

Daddyo Tom, help the people over here but please watch the collapses first. Reading the NIST report tells you 50% (or may be nothing) if you never saw what they talking about. Listen to the witness testimonies! Compare both sides!
Allow your brain to think about questions like "Why has Pitts written that the fire was burnt out at 3:15 and why has McGratton simulated a lot of fire until 5:xx? Well, both is NIST and the difference between the visual evidence and the ignoring of the visual evidence is the goal that has to be achieved.

Nazi Germany? I know Tom, it was *nut. I answered with Bush's grandpa. It's all the same crappola from the beginning to page 35 and we could do it for the next 100 pages.

Hey, NIST said the tower jumped.
NO, no way. You must be joking.
What? What's your reputation to say something like that?
Brrrbrlrnbj!
That's what I knew befor! You are some 13 year old fascist and the tower jumped! I saw it. I saw a superb simulation with a good portion of failure in it. I swear the tower jumped. And completely collapsed.
Why?
The core wasn't able to stand after jumping.
What?
The core wasn't able to stand after jumping. What's the mystery? You don't know nothing about engineering, right. After the tower jumped it collapsed. That's absolutely normal for a jumping tower.
Are you crazy?
Hey, show me your diploma or shut the **** up! The tower collapsed right after jumping, got it, you 13 year old Nazi lunatic.

No doubt, Tom can guarantee the stresses. No doubt, it began to sag after the swaying ended? The No-Planer argument is just funny but yes, it's the way the things going over here right? Should it sag in the north or in the south? Doesn't matter, right Tom?

Sorry guys! Good night and good luck!

 

[beachnut]

...
Suggest folk take care to not get too carried away within their own particular trains of thought.

With your 911truth train of thought in mind, please explain why your fellow super-engineer achimspok says Grandpa Bush has something to do with Tony's missing jolt?

And how about the line up on these bending exterior columns who make up the main lateral support for the core? Have you asked Robertson who designed the structure of the WTC towers why you and Tony have failed for 8 years to understand the collapse? Robertson seems to understand the collapse; why don't the 911 truth engineers?

Would this be a slow jolt? How does bending columns being heated by office fires after being set by 10,000 gallons of burning jet fuel work in the world of delusions you and Tony live in?

Which part of your post was in support of Tony's missing jolt paper? Can you help his paper be published in a real engineering Journal?

... Allow your brain to think about questions like "Why has Pitts written that the fire was burnt out at 3:15 and why has McGratton simulated a lot of fire until 5:xx? Well, both is NIST and the difference between the visual evidence and the ignoring of the visual evidence is the goal that has to be achieved. ...
Sorry ...!

is this for the missing jolt thread. The towers were burning right up to collapse; what happen in WTC7 is another thread as is the nazi junk and granpahbush moronic tripe.
What does WTC7 on fire have to do with the missing jolt in a tower? Do you think the video resolution and fps would allow Tony to see the jolt he is looking for, and why?

imntspok, imkeith

 

[femr2]

Which part of your post was in support of Tony's missing jolt paper?

I would have thought it would be easy for you to see that I indicated one reason (made very simple by being able to see it in a simple animated 3D stick model ) why a single large magnitude *jolt* may not be expected. Clearly not.

I've made the scope and purpose of the model as clear as needs be as far as I'm concerned. The only purpose of my brief visit.

Take care.

 

[beachnut]

I would have thought it would be easy for you to see that I indicated one reason (made very simple by being able to see it in a simple animated 3D stick model ) why a single large magnitude *jolt* may not be expected. Clearly not.

I've made the scope and purpose of the model as clear as needs be as far as I'm concerned. The only purpose of my brief visit.

Take care.

I thought you supported the CD 911 truth delusion. Your continuous impacts was noted and does not support CD or thermite claims.

Will you be taking down your delusional you-tube videos of CD? Or is your special treatment of mechanical floors with delusional CD techniques still in play as your conspiracy theory fantasy?

Jolt is out, got it! CD is???

 

[achimspok]

is this for the missing jolt thread. The towers were burning right up to collapse; what happen in WTC7 is another thread as is the nazi junk and granpahbush

Beachnut, the nazi junk was YOUR post! Need a link? No I think you need help.

 

[beachnut]

Beachnut, the nazi junk was YOUR post! Need a link? No I think you need help.

Femr2 has no jolt, what say u?

Jolt? No Jolt?

What did your WTC7 fire have to do with a Tower Jolt? A little help, it has been years since grad school...

imntspok, imkeith

 

[achimspok]

Beachnut, the nazi junk was YOUR post! I replied with grandpa Bush.

You really need help.

 

[beachnut]

Beachnut, the nazi junk was YOUR post! I replied with grandpa Bush.

You really need help.

http://journalof911studies.com/volume/2008/TheMissingJolt4.pdf

Jolt or no Jolt, and why? What is your take?

Do you agree with Tony or femr2?

 

[achimspok]

Jolt or no Jolt, and why?

No jolt in the sense of a thousand "jolts". Imo the top was nearly in permanent contact to the lower part.

Would you say the floor slaps bowed 3m downwards in 20min and were capable to pull the columns inward?

 

[beachnut]

No jolt in the sense of a thousand "jolts". Imo the top was nearly in permanent contact to the lower part.

Would you say the floor slaps bowed 3m downwards in 20min and were capable to pull the columns inward?

This floor is disconnected. With impacts 7 to 11 time greater in kinetic energy than designed what do you expect with impacts as great as 1300 to 2,000 pound bombs?

WWSD... What does fire do to steel? Like this building, the WTC is not immune to fire.

? trick question?

Did the shell columns which gave the WTC the outstanding lateral support bow?

I hate trick questions.

Not hard to hit the largest buildings in the world on 911 with nearly calm winds and perfect weather.

No little jolt and no big jolt; so Tony's attempt at backing in CD like all of 911 truth has failed for 8 years.

 

[tfk]

Achim,

You don't listen very well. Or perhaps you don't hear other voices because the ones inside your own head talk so loud.

"Ah, Germany is known for..." "You said Chicago first." "Achim must be 13."

You'd do better if you paid attention to who said what.

I didn't mention Germany, in any but respectful tones.

I said your argument was worthy of a 13 year old. And it was.

What tfk going on here? Engineering? Can't find anything like that.

Neither have you brought anything like engineering.

It's BLA BLA, Tom! You have proven that you know near to zero about the collapses.

You haven't brought the slightest discussion about the collapses. You've made a few baseless assertions. If you want to make some arguments, make them. Nobody (except you) is stopping you. But you wander off into all this other irrelevant nonsense.

All you have repeated was a completely wrong NOVA animation.

You don't listen very well. NOVA is a TV station. NOVA's (& the BBC's, and the NYT's) versions of what happened on 9/11 are of precisely zero interest to me. Because reporters know next to nothing about what happened. They get their info from engineers. And they get their facts wrong all the time. What the engineers say matters to me.

BTW, you've dodged the question for about the 3rd time. What is YOUR engineering background, if any?

If you really (or anyone here) would have the engineering experience you coquet with THEN ... Oh, I don't know. That NIST animation is such a crap that you probably immediately would have lost your last white hair and 40pounds of weight. However.

"coquet" is the wrong word. Perhaps "claim".

The NIST animation? WTC7?

If that is the one you are referring to, I don't believe it.

Oh, I believe that they got the failure mode right. I believe that they got the collapse initiation right, because of external evidence.

But after the first couple seconds, I think that the collapse was far too chaotic to be captured in detail by their (or anyone's) model.

There is an ART to interpreting models like this. You further you wander from known states, the less reliable they are. I think that NIST made a serious error by trying to run this model of the entire collapse. I think that they MAY HAVE done so because of political pressure, for not having modeled the total collapse of the towers. If that was the case, I think it was a bad decision.

Catenary forces, Tom? (Just north south?)

There was a fundamental difference between the north-south trusses & the east-west trusses.

55 inches inwards?

Yup.

20 minutes after the first window broke due to surface temperature?

A fair number of the windows in the area of the early fires had been broken by that little issue of a 120 ton jet flying thru them. What is your point about the windows & the 20 minutes? Thin steel like the trusses can easily buckle in 20 minutes. Or less.

Shear forces, Tom? ...shearing the perimeter columns above and below the spandrels but the floor connections didn't fail?

Do you even know what "shear forces" are?

Someone here described how the damaged tower had to distribute all loads to the south because of the damage in the north and therefore the tower HAD TO bow and collapse in the south.

Why does the fact that you've been able to absorb or restate absolutely nothing of what I've said give me zero confidence that you are quoting this innominate person accurately?

Well, the south tower did simply the wrong thing, right?

Did the planes hit the same? Do you expect all cars in accidents to spin off at the same angles? Are you clueless about the clearly explained reasons why each building fell in the direction that it did? Have you looked at the load and strain diagrams in NCSTAR1-6D?

Reading the NIST report tells you 50% (or may be nothing) if you never saw what they talking about. Listen to the witness testimonies! Compare both sides!

Ahhh, ignore the PhDs in Structural Engineering, but listen to ... Professors of Comparative Religions? Radio shock jocks? A stock broker?

I have listened to both sides. The Structural Engineers know what they are talking about. The religious studies professors, the radio shock jocks, the stock brokers (& you) don't.

Tom

 

[Dave Rogers]

In the context of this particular thread, for me, what it showed (in it's utterly infant form) was that for a 3 degree tilt, the distance between the 99th and 98th floor on the south edge was probably pretty small, and that any subsequent vertical drop would involve a pretty continuous series of impacts between the floors themselves, followed by the 1000 series columns (to a certain extent, without getting into the whole column alignment malarky), followed by the core bracing, followed by the 900 series columns, followed by...

Pretty simple observations in my book, fairly obvious, but useful to be able to see it.

Result ? Lots of smaller magnitude *jolts* over a period of time. Once the angles are worked out a bit more accurately, might even go so far as to estimate a period of time for that series of sequential impacts.

It doesn't really need an animation, though. I arrived at the same conclusion using simple trigonometry and a spreadsheet.

Good luck getting Tony to believe you.

Dave

 

[achimspok]

You'd do better if you paid attention to who said what.

Please Tom, don't try again to make a case out of nothing. I responded to all that barking around here not just to you. Btw, you are the most sympathetic here. I never thought I would write something like that ever in my life. Well, it's a question of the pool you are swimming in at the very moment. Btw, I bet that German beer. Imo Femr do a very good job what ever he think about the whole topic. At least it is a question what you expect a model should do or can do and btw it is a usual way to start with a simple model.

You don't listen very well. NOVA is a TV station.

Yes, I know. I saw Sunder explaining that TV animation step by step. You tried to explain the initiation sequence in the very same way. If you ever find the time then watch the video *nut linked a frame. The sequence you described is wrong. That's not a question of "troofers" or CD or what ever. It simply didn't happen that way.

There was a fundamental difference between the north-south trusses & the east-west trusses.

Right. Nevertheless the long trusses were connected via support trusses east-west connected to the east and west walls. How may I imagine a 10ft sagging resulting in a inward bowing of 55in without deformation of the east and west face? (That's not a rhetorical question. It's just a question.)

What is your point about the windows & the 20 minutes? Thin steel like the trusses can easily buckle in 20 minutes. Or less.

The windows in the SE survived the impact. Therefor you 120ton argument doesn't matter. Windows (I gave you a link at the911forum) brake almost immediately in the moment a surface temperature of 600°C is first reached. Therefore the surface temperature of the perimeter columns until 10am was lower. Since the windows were unbroken in that area the (renovated) fireproofing in that area should be intact too. So far it is confirmed by NIST.
A substantial fire in that area (even in the middle of the long trusses and 9m away from the windows) would result in a fast rising temperature even at the windows surface. So far it is confirmed by the visual evidence (no visible fire - unbroken windows and vice versa). After 75 minutes of substantial fires on all impacted floors no fire spread into the east half of the south side of all involved floors.
The behavior changed dramatically in the very moment the WTC2 started to collapse (no as a result of suction or ground shaking). You can observe a darting flame from the center of the floor resulting in 3-4 floors high flames within a second. Minutes later the whole south east burnt on several floors. The windows failed immediately.
Now I would expect the still fireproofed trusses and exterior columns to withstand that fire for a while since it was a "usual" office fire. (No need to remind me of the damage and subsequent deformations and load distributions.)
20 minutes after that fire started (and the windows were broken) NIST measured the maximum of inward bowing right in that area. They tested the behavior of the trusses. They simulated the fire. All that confirms that the trusses wouldn't sag 3 meters in that short time. If they would or could then it should be easy to calculate the catenary forces. It should be possible to simulate or calculate the necessary forces bow a grid of perimeter columns 20 minutes in a "office fire". (No need to say that a much longer fire in the SW resulted in no visible bowing and therefor apparently not in any floor sagging of at least a comparable magnitude. Nevertheless, here the fireproofing was damaged and probably kerosene was involved at least in the first minutes of the fire.)
Imo the trusses didn't sag that much even in WTC2. There a good visual sources but nowhere you can find a clue for a sagging of that extend (the floor slap would hang down to the floor below).
Now it needs a lot of fantasy to blame the fire for that extreme sagging withing 20 minutes. Imo other forces and deformations must be involved and the only answer I can imagine is an extreme core deformation. (You did the XY vs. IB calculation and it tells the very same. It's not about 10 or 20 inches.)

I know, you don't give a damn. The perimeter was bowed. End of story.
That's not my way to look at it.

Do you even know what "shear forces" are?

C'mon Daddyo! What kind of force would either "shear" the bolts of the floor connections or "cut" the columns above an below the spandrels?
Sunders: "...and suddenly the columns snapped and as a result..."
No, the columns didn't snap! Once the collapse started the bowed columns started to bow more and more. At some point (about half a floor height down) the connections between the panels failed. The lower panels were spanned over the lower floors and "snapped" outwards. The breaking of the bowed exterior columns was not the initial failure that started the rapid progression of global failure and the descent of the top. (And please spare me something like "the initial failure was caused by the airplane".)
In fact, NIST had a problem to simulate or reconstruct the floor sagging.
I don't know if there ever tried to test inward bowing that way. I don't think so.
The "snapping columns" didn't happen that way Sunder described it.
I have a problem with it. You don't. Fine.
I try to see the events in the context of hundreds strange coincidences that day.
You don't have a problem with it. Fine.
Well, I bet the German beer but success is always a question of expectation, right?

@Bnut
I'm totally impressed.
Nobody ever said that the WTC was immune to fire.

 

[Tony Szamboti]

It doesn't really need an animation, though. I arrived at the same conclusion using simple trigonometry and a spreadsheet.

Good luck getting Tony to believe you.

Dave

Can you tell us where to find this spreadsheet data of yours, with the energy dissipations and the tilt angle at each separate impact location, as the collapse proceeds? I have been asking you for it for a while now.