WTC7 - The fires failed Girder 44-79

[Newtons Bit]

So they don't use the physical evidence? Interesting concept.

Engineering is a math-based design process created using theoretical concepts validated through physical testing. The entire point is to do things as efficient and cost effective as possible. There is no need to have physical anything to run an engineering analysis.

 

[carlitos]

I don't understand how those who think that all modeling has to be physical could ever cross a bridge, take an elevator or fly in a plane. What in the world do they think engineers do?

 

[ozeco41]

We should get this thread retitled:
"Game Playing by 'One Trick Ponies'"
...they can each play their favourite 'one trick'. So, for Tony, 000063 has identified the two tricks of 'limit the factors' and 'reverse burden of proof':

...Curious. All you do is try to stick to a small subset of the evidence and reverse the BOP...

...actually Tony has a couple of other tricks - but he rarely deploys more than the minimum number needed to evade questions or avoid presenting support for his false claims.

So in this thread he has continued the practice he started in the predecessor thread and he has focussed on the duo of:
1) Limiting himself to as few factors as he can get away with; AND
2) Attempting reverse burden of proof as often as he can get away with it.

The other 'pony trick' he practices routinely is 'make sure you have no model of mechanism to underpin fancy maths or FEA's' (...and, for the non-engineers, be aware that there is no mystique or magic about an FEA - it is simply a lot of 'fancy maths' in reality made practical these days that we have computer power to spare ) (The method allows you to include many more factors - hence need for computer - it was impractical back in the days of slide-rules - ironic given that Tony has chosen to limit factors in his recently described attempts at FEA. So he tries to attract the 'mystique and magic' of FEA whilst still limiting the factors to make sure he gets the answers he wants. .....but.....let's not go there at this stage.. it's been obvious for a long time... )

The 'one trick' of 'have no mechanism under your maths' could be Tony's trademark. I first met it in a paper 'Engineering Reality' back in 2007 and it was the main error of 'Missing Jolt'. More recently it has raised its head again in Tony's approach to this girder walk-off topic and in his approach to the derail discussion of Twin Towers collapse initiation on the predecessor thread.

Bottom line is that Tony shows signs of behaving as a 'one trick at a time pony' though he does have several tricks whereas RedIbis seems to be your literal 'only has one trick' pony:

That's not what Tsig said.

...as I have said on (several) previous occasions Red looks for a hole in logic of the debunker claim - usually a genuine weakness but in this case a pretended one (Pretending to not recognise the context of tsig's statement) - then he plays word games - again usually by playing off a 'narrow' definition of a word against a 'broad definition'. So it is no surprise that every time he joins in a thread it is still the same pony with the same 'trademark' 'one trick'. The only other thing that doesn't change is how few debunkers call him on the actual tactical trick.

A further thought... it appears, given the lack of evidence presented by the Truthers, the endless attempts to avoid questions and divert the arguments into meaningless word games, what we have left from them is not a quest for truth. It is a quest to avoid having to change their mind.

Which is why I prefer to separate truthing from trolling - with "quest for truth" as the difference. If the member clearly demonstrates no intention to progress discussion towards truth and shared understanding then the posts are trolling. And feeding the trolling is a waste of time - especially any appeal to logic, consistency, reason.....

Conversely progression of reasoned discussion could indicate a genuine search for truth.

 

[Justin39640]

I don't understand how those who think that all modeling has to be physical could ever cross a bridge, take an elevator or fly in a plane. What in the world do they think engineers do?

These days very few prototypes are physically built. Most exist in the virtual world. Most of the machines I work on are designed and proved without a single die being lifted. Straight from AutoCAD to the production line.

 

[tsig]

So they don't use the physical evidence? Interesting concept.

Well when I did engineering I used math first then matched the materials needed to what the figures told me.

In this case when I apply the math to the strength of the materiel it's obvious that the buildings collapsed by gravity.

It's the ² in the equation e=mgh that's the killer.

 

[ozeco41]

Engineering is a math-based design process created using theoretical concepts validated through physical testing. The entire point is to do things as efficient and cost effective as possible. There is no need to have physical anything to run an engineering analysis.

I don't understand how those who think that all modeling has to be physical could ever cross a bridge, take an elevator or fly in a plane. What in the world do they think engineers do?

Given that RedIbis is waiting for apparent holes of logic lets remember that engineering is based on physical evidence....

...but most of it shifted in time. Often shifted by decades or longer.

Let's recall the context. There are two questions behind all this discussion of WTC steel which are:
1) The genuine need to explain the collapses of those buildings so that lessons can be learned for future buildings; AND
2) Meet the false claims and unsupportable expectations of truthers on the presumption that either CD needed to be explained OR that all anomalies raised by truthers should be explained at cost to the public purse.

"1)" is the legitimate question for investigation. Both premises of "2)" are not legitimate. There was no CD and no prima facie case that needed investigation AND public policy has to draw a line as to how far a society goes to satisfy the desires of a dishonest or deluded minority pursuing political goals.

So back on the 'time shifted' aspects of physical evidence.

The physical characteristics of the steel of WTC were known before construction. And determined by testing and measurement of physical attributes. So the analyses of collapse mechanisms conducted after 9/11 are based on physical evidence.

Most of the alleged reasons (usually unspecified) why truthers/trolls call for post 9/11 physical testing are in support of CD related claims. There was no CD therefore no such testing has any purpose.

And, yes, I am well aware of how truthers reverse that logic to make claims with a shallow semblance of pseudo legitimacy.

 

[tfk]

you should be telling me why there was no photographic evidence of fires in WTC 7 until at least 12:15 PM and all about the fire alarms and why they were set to test mode that morning.

I'll make a chain of speculations which, unlike Tony's ludicrous appeal to "suspicious by LACK of evidence", actually consider what was going on that day.

I readily admit that this a combination of unquestionably known events, and some speculation about human behavior under extreme duress. I feel comfortable with my speculation.

I invite anyone to offer what they think is a more plausible speculation, along with their reasoning, at any juncture.

I will ignore any "well, prove this", as stupidly clueless about the nature of this exercise.
___

1. My SWAG is that about 95% of the video & photo evidence available are from ground based cameras (as opposed to airborne).

2. There is zero airborne photo- or video-graphy after some time that morning, because the FAA ordered all planes & helicopters to land, including police & news choppers.

3. The south tower began to collapse. It caught everyone by surprise.

Photojournalists are not Olympic athletes. You are invited to try running thru mobbed streets with your brain SCREAMING that tons of steel are heading towards you, and you don't know where they'll land. That's puts a little motivation into your pace. "Leisurely saunter" was not the order of the day.

So I contend that everyone ran, gripped in terror, as fast as they could and as fast as the goddamn people in front of them permitted. Until they were enveloped by an unimaginable dense, choking cloud that plugged every orifice. (Do you remember the images of the people that emerged from that cloud?)

4. At this point they either took refuge wherever possible, or stumbled thru the streets, filling their eyes, ears, nose, throat & lungs with crap. Until they reached the edge of the cloud ...

5. ... and STARTED the process that EVERYONE ELSE was doing at the same time: looking for water to wash away the dirt.

Perhaps photojournalists are such a-holes that they'd push themselves to the front of that line. I don't think so. Perhaps they'd announce to the other New Yorkers, also gasping for air, who'd gotten to the water source first, that "I should go to the front of the line because I, after all, work for the New York Times!!" Perhaps, but I doubt it.

Perhaps the average Manhattanite, in the midst of the single most stressful minutes of their entire lives & also desperate to breathe again, would be so impressed & awed by this announcement that they would meekly step aside with friendly comments of "Of course. What was I thinking. Please go in front of all of us." Yeah, right.

6. >98% of the civilians (not rescue workers, not photojournalists) in the area selected the "better part of valor" option & evacuated, taking with them whatever cameras they might have had. Cameras witch had contributed significantly to the total record.

7. But some photographers waited for the cloud to dissipate. After all of the above, everybody in the area was seriously freaked. And, in this state, any photographer had to make the choice of whether to follow the hordes who were leaving the area, or to head back into the cloud.

Some left, some returned. I don't know what the ratio was. I am certain it was neither 100%:0% nor 0%:100%.

8. Returning to the area, after the smoke from wtc2 began to clear (20 - 30 minutes?), were rescue workers & a small number of dedicated photojournalists. Rescue workers don't take pictures. They've got more important things to do.

9. Then the North Tower began to collapse & and they went thru the whole exercise again..!

10. The 2nd cloud was even bigger than the first. (First order guess: 2x bigger south of tower 1, and 1.2x bigger north of it.) Everyone ran for their lives, a long way, to get out of the choking dust cloud.

11. I would wager that it was a small fraction of the remaining photographers who chose to wade back into the scene after the 2nd collapse, and the rest decided that they'd had enough.
___

So, in summary, I contend that the succession of the these events:

... the clearing of the airspace, collapse #1, evacuation (of the area and your bowels in terror), getting to breathable air, cleaning yourself up enough to breathe, waiting for the cloud to dissipate, finding the courage to walk back into the carnage, then

collapse #2, repeat of that whole cycle,

... resulted in far fewer cameras around ground zero (& wtc7) than earlier.

I contend that the above events (from the north tower collapse until photographers were back into ground zero) could easily have taken 30 to 90 minutes to play out.

I contend that those far fewer cameras were dispersed over a very large disaster site.

I contend that building 7, while damaged but not yet obviously burning, would not have pulled a photographer's eye away from the completely demolished towers & surrounding devastation, UNTIL it showed signs significant fires.

I contend that there is nothing the slightest bit nefarious, suspicious or the slightest bit surprising about a 90 minute delay between the collapse of the North Tower & one of the few photographers in the area noticing it, and snapping a picture.

I contend that Tony's breathless, accusatory "well, well, well how do you explain THIS not happening" is an absolutely typical bit of "Szamboti Buffoonery".
___

That's my speculation. For all, except the last paragraph above.

That last paragraph is absolute fact.

 

[Tony Szamboti]

So, is it your position that there were no fires until after noon and they were intentionally set?

Why were there no pictures? I don't know, maybe it had something to do with everyone having better things to do than walking around sight seeing. Do you really find this odd?

Why was the alarm set to "test"? I don't know. For me, the first thing I would do if I was going to burn down a building with thousands of firefighters around would be, make the alarm so it won't call the station. Makes sense to you?

I don't have the whole story, never claimed I did. I also don't go looking for reasons to be suspicious about something I see as straight forward. Got any good reason I should be suspicious?

Freefall acceleration of a football field size building should make you and anyone else suspicious.

And yes, I do think the fires were intentionally set. I do not believe flaming embers from 350 feet away set those fires in WTC 7. In reality, the collapses of the towers should have smothered the fires in them and there would have been nothing to set thing as far away as WTC 7 ablaze unless an electrical short or something like that was caused in the building hit with debris.

Fires on 10 floors of WTC 7 being caused by the North Tower collapse is nothing short of hocus pocus.

 

[Tony Szamboti]

I'll make a chain of speculations which, unlike Tony's ludicrous appeal to "suspicious by LACK of evidence", actually consider what was going on that day.

I readily admit that this a combination of unquestionably known events, and some speculation about human behavior under extreme duress. I feel comfortable with my speculation.

I invite anyone to offer what they think is a more plausible speculation, along with their reasoning, at any juncture.

I will ignore any "well, prove this", as stupidly clueless about the nature of this exercise.
___

1. My SWAG is that about 95% of the video & photo evidence available are from ground based cameras (as opposed to airborne).

2. There is zero airborne photo- or video-graphy after some time that morning, because the FAA ordered all planes & helicopters to land, including police & news choppers.

3. The south tower began to collapse. It caught everyone by surprise.

Photojournalists are not Olympic athletes. You are invited to try running thru mobbed streets with your brain SCREAMING that tons of steel are heading towards you, and you don't know where they'll land. That's puts a little motivation into your pace. "Leisurely saunter" was not the order of the day.

So I contend that everyone ran, gripped in terror, as fast as they could and as fast as the goddamn people in front of them permitted. Until they were enveloped by an unimaginable dense, choking cloud that plugged every orifice. (Do you remember the images of the people that emerged from that cloud?)

4. At this point they either took refuge wherever possible, or stumbled thru the streets, filling their eyes, ears, nose, throat & lungs with crap. Until they reached the edge of the cloud ...

5. ... and STARTED the process that EVERYONE ELSE was doing at the same time: looking for water to wash away the dirt.

Perhaps photojournalists are such a-holes that they'd push themselves to the front of that line. I don't think so. Perhaps they'd announce to the other New Yorkers, also gasping for air, who'd gotten to the water source first, that "I should go to the front of the line because I, after all, work for the New York Times!!" Perhaps, but I doubt it.

Perhaps the average Manhattanite, in the midst of the single most stressful minutes of their entire lives & also desperate to breathe again, would be so impressed & awed by this announcement that they would meekly step aside with friendly comments of "Of course. What was I thinking. Please go in front of all of us." Yeah, right.

6. >98% of the civilians (not rescue workers, not photojournalists) in the area selected the "better part of valor" option & evacuated, taking with them whatever cameras they might have had. Cameras witch had contributed significantly to the total record.

7. But some photographers waited for the cloud to dissipate. After all of the above, everybody in the area was seriously freaked. And, in this state, any photographer had to make the choice of whether to follow the hordes who were leaving the area, or to head back into the cloud.

Some left, some returned. I don't know what the ratio was. I am certain it was neither 100%:0% nor 0%:100%.

8. Returning to the area, after the smoke from wtc2 began to clear (20 - 30 minutes?), were rescue workers & a small number of dedicated photojournalists. Rescue workers don't take pictures. They've got more important things to do.

9. Then the North Tower began to collapse & and they went thru the whole exercise again..!

10. The 2nd cloud was even bigger than the first. (First order guess: 2x bigger south of tower 1, and 1.2x bigger north of it.) Everyone ran for their lives, a long way, to get out of the choking dust cloud.

11. I would wager that it was a small fraction of the remaining photographers who chose to wade back into the scene after the 2nd collapse, and the rest decided that they'd had enough.
___

So, in summary, I contend that the succession of the these events:

... the clearing of the airspace, collapse #1, evacuation (of the area and your bowels in terror), getting to breathable air, cleaning yourself up enough to breathe, waiting for the cloud to dissipate, finding the courage to walk back into the carnage, then

collapse #2, repeat of that whole cycle,

... resulted in far fewer cameras around ground zero (& wtc7) than earlier.

I contend that the above events (from the north tower collapse until photographers were back into ground zero) could easily have taken 30 to 90 minutes to play out.

I contend that those far fewer cameras were dispersed over a very large disaster site.

I contend that building 7, while damaged but not yet obviously burning, would not have pulled a photographer's eye away from the completely demolished towers & surrounding devastation, UNTIL it showed signs significant fires.

I contend that there is nothing the slightest bit nefarious, suspicious or the slightest bit surprising about a 90 minute delay between the collapse of the North Tower & one of the few photographers in the area noticing it, and snapping a picture.

I contend that Tony's breathless, accusatory "well, well, well how do you explain THIS not happening" is an absolutely typical bit of "Szamboti Buffoonery".
___

That's my speculation. For all, except the last paragraph above.

That last paragraph is absolute fact.

North Tower collapses at 10:28 AM and the first photos of fires in WTC 7 were taken at about 12:15 PM. That is a 107 minute delay. The dust settled within a half hour and the police helicopters would not have landed right after the North Tower went down and would have been looking for problems. Why didn't they see anything?

 

[LashL]

Get back to the topic of the thread, stat.

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

 

[beachnut]

Freefall acceleration of a football field size building should make you and anyone else suspicious.

And yes, I do think the fires were intentionally set. I do not believe flaming embers from 350 feet away set those fires in WTC 7.

Not understanding gravity, denying the collapse lasted for over 16 seconds leads to the CD fantasy for WTC 7. Now more fantasy, delusions of fires being set.

The debris hit WTC 7, it was zero feet for the fire to travel, zero. Fire was dropped on WTC 7. Explain how a fire goes out when there is no water to put it out and it is flung into a building, through the air, fire likes air, lots of air, making the burning office contents burn more. Air is needed to make fire burn better. Guess you don't like the "flaming arrow" theory. Deny history, ignore gravity, spread the fantasy of CD based on, nothing.

Who set the fires? Terrorists set the fires by running two jets filled with 66,000 pounds of fuel in each. This is not engineering you are using, it is nonsense. The collapse of the WTC towers set WTC 7 on fire; there was no water to put out the fires. Is the MIB setting the fires a new theory?

 

[Robrob]

Get back to the topic of the thread, stat.

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

So you exiled the "off topic" responses but left the "off topic" post they addressed?

 

[LSSBB]

Freefall acceleration of a football field size building should make you and anyone else suspicious.

How long was the visible portion of the building AT freefall acceleration, Tony?

 

[Tony Szamboti]

How long was the visible portion of the building AT freefall acceleration, Tony?

NIST tells us it was 2.25 seconds or about eight stories of the fall. Please bear in mind that irrespective of any argument about columns having a minimum resistance during buckling, that there would be eight stories of mass to be accelerated by the falling upper mass if the collapse were natural. This would cause a decrease in velocity due to conservation of momentum alone. Why don't we see this?

 

[LSSBB]

NIST tells us it was 2.25 seconds. Please bear in mind that irrespective of any argument about columns having a minimum resistance during buckling, that there would be eight stories of mass to be accelerated by the falling upper mass if the collapse were natural. This would cause a decrease in velocity due to conservation of momentum alone. Why don't we see this?

Interesting. And what did NIST's acceleration curve show? How long do YOU say it was at freefall? Please take into account measurement error when providing your answer.

 

[000063]

Freefall acceleration of a football field size building should make you and anyone else suspicious.....

Time to first lie; first sentence.

North Tower collapses at 10:28 AM and the first photos of fires in WTC 7 were taken at about 12:15 PM. That is a 107 minute delay. The dust settled within a half hour and the police helicopters would not have landed right after the North Tower went down and would have been looking for problems. Why didn't they see anything?

Because 7 was, how do you say, not the priority. The priority and focus of most people would be the two buildings that just collapsed with thousands of people, including cops, in them, or Golf Tango Foxtrot Oscaring.

NIST tells us it was 2.25 seconds or about eight stories of the fall. Please bear in mind that irrespective of any argument about columns having a minimum resistance during buckling, that there would be eight stories of mass to be accelerated by the falling upper mass if the collapse were natural. This would cause a decrease in velocity due to conservation of momentum alone. Why don't we see this?

You mean the 2.25 seconds that were the middle period of three periods where the portion measured was moving at less than FFA, indicating that there was, gasp, resistance?

You realize that you can't say the entire building was collapsing if the E. Penthouse had already collapsed, right?

You do know that eight is less than 47, right?

 

[ozeco41]

NIST tells us it was 2.25 seconds or about eight stories of the fall. Please bear in mind that irrespective of any argument about columns having a minimum resistance during buckling, that there would be eight stories of mass to be accelerated by the falling upper mass if the collapse were natural. This would cause a decrease in velocity due to conservation of momentum alone. Why don't we see this?

Once again we see Tony's characteristic back to front "logic". He starts claiming something about reality then goes round in a big circle to prove reality was wrong OR his starting assumptions were right OR some similar bit of circular nonsense. Remember "Missing Jolt" as probably the most prominent example of circularity of logic??? (He "proved" his main assumption right in that one.)

For this bit of confused thinking the starting point should be that there was a period of observed falling of the outer shell for about 2.5 seconds and at about FFA.

Now the challenge for both sides of the "CD or no CD?" argument is to explain how that bit of reality was either consistent with their conclusion OR inconsistent with the opposing sides conclusion OR both.

Simple enough setting.

Are Tony's comments a) Valid and/or b) Relevant?

1) POINT 1 - "NIST tells us..." - actually says nothing - but it is a standard Tony 'framing ploy' to confuse the object of discussion. Are we discussing "What really happened?" OR "NIST was wrong version X^TSz?"

Let's go with "What really happened?" for now unless Tony says he is not discussing "What really happened?"

So the issue with POINT 1 - "NIST tells us..." is really "Do we (both sides) agree that there was "...a period of observed falling of the outer shell for about 2.5 seconds and at about FFA". Tony is relying on it for his claim and I don't see debunkers disagreeing. So we can set aside the following two matters unless someone can show that they need to be dealt with:
(a) all the nit picking about 'at or about or over FFA' and
(b) arguments about the timing tighter than let's say 0.7 second either way.

2) POINT 2 - "Please bear in mind that irrespective of any argument about columns having a minimum resistance during buckling," OK by me.

3) POINT 3 - "...that there would be eight stories of mass to be accelerated..." Tony starts to tilt the playing field to suit his pre-determined conclusion. All we know is "eight stories of façade mass plus whatever may be attached somehow and out of sight..." So explicitly drop the implication that it is eights storeys total mass please Tony.

4) POINT 4 - "...by the falling upper mass..." Confused thinking or deliberate attempt to mislead? Dunno - it could easily be both. WTF is he talking about - at least he needs to make clear the underlying model he is describing ...which could lead us to another standard Tony ploy i.e. lack of a clear mechanism.... It is the mass falling at FFA we are interested in - not some alternate 'upper mass' somehow impacting on it.

5) POINT 5 - "...if the collapse were natural." EH??? Why does it differ between "natural" and "man made"? The physics is the same. We see a bit of building falling with certain speed/acceleration parameters. Said falling resulting from some causal mechanism. Whether the causal mechanism is CD or 'natural' the same physics applies. Tony is again either not thinking clearly OR trying to tell porkies.

6) POINT 6 - "This would cause a decrease in velocity due to conservation of momentum alone. Why don't we see this?" Well I think I can see where the confusion is coming from but better if Tony tries again to sort out this bit - otherwise "gobbledegook" comes to mind.

 

[BasqueArch]

NIST was right . The beams pushed the girder off its seat. As the girder was pushed, buckled and deflected greatly, the heated seat could also have failed.

Originally Posted by Tony Szamboti
No, the slides do not show the girder buckled. It is deflected. The beams keep it from rotating and for lateral torsional buckling and vertical load capacity to be lost the beam or girder needs to rotate. NIST used a rule of rotation equal to half the flange width for saying the beam or girder lost its load carrying capacity. That did not occur in the FEA I sent you the results of.

Additionally, the girder gets locked up against the flange of column 79 due to thermal expansion and is unable to traverse westward. So I don't see how you got the notion that the bottom flange moved more than 6.5 inches. On top of that the beams can't expand more than about 4.75 inches no matter what the temperature was due to sagging induced shortening becoming greater than expansion at a little over 600 degrees C. Then there are the flange stiffeners which would require about 9 inches of westward travel before the girder would come off the seat.

There is no chance that girder came off its seat under any fire heating scenario.

Other engineers show this is wrong.
TS’ FEA color gradient displacement slides show:
[1] The girder expanded along its length and was restrained by cols. 79 and 44. = buckled
[2] (Measurements rounded to one decimal point.) The girder is shown with a west displacement of 0.1 to 2.6 inches for a distance of ~ 1 foot from the trapped girder end at C79 and by the flange at C44. The rest of the girder is shown having moved west by 3.8 to 6.3 inches. = buckled. (due to 0.1 to 6.3 inches horizontal differential)
[3] The 3D graphics show the girder rotated about its vertical axis and deformed about its horizontal axis. = buckled.

“Restrained beams, when exposed to fire, develop significant restraint forces and these forces
can alter the response of the beam. The development of fire induced forces, and gradual
softening of steel resulting from high temperature, produce large deflections in the beam.
Strength failure occurs in the beam either when the capacity of the connections is exceeded due to large rotations, or when a plastic mechanism develops in the beam after undergoing large deflections.
There have been limited studies on the behavior of restrained beams under fire conditions.
Fire resistance tests on axially restrained steel beams revealed the development of significant axial force and large deflections due to restraint [1-3].” Pp.106

(Thanks to Sunstealer’s link of Structures in Fire - Proceedings of the Sixth International Conference. 123 papers selected for publication,2010)
http://www.egr.msu.edu/sif10/flyer of conf/SiF10 Conference Proceedings.pdf

“….. As steel temperature continues to increase with fire exposure time, softening of steel causes larger deflections and rotations until the first plastic hinge develop in the beam. The plastic hinge, which forms at the location of maximum bending moment in the beam, causes sudden increase in deflection (see Fig.1(c)), which leads to reduction and then reversal of the axial force in the beam from compressive to tensile force.
The beam enters a catenary phase in Stage III when the fire-induced compressive axial force vanishes as shown in Fig. 1(b). In the catenary phase, tensile force develops in the beam and the load bearing mechanism gradually shifts form flexural to cable (tensile) until failure occurs by rupture of the beam (or in the connections). When the beam undergoes the above three stages, it is assumed that the connections continue to perform elastically. Therefore, fire-induced forces and rotations in the beam must not exceed the connections capacity.”
P. 107. – ibid.

TS’ slides show the girder buckled. The slides show the horizontal displacement but not the large vertical deflections of the girder. The girder was pushed and twisted past the seat by the expanding and sagging beams or the girder fractured and failed.
The weight of the buckled beams, with a 20” deflection (NIST), and whose horizontal axes were above the girder’s horizontal axis, torqued the girder towards the beams. The girder’s bottom flange rotated past the already 6.3” bottom flange lateral displacement.

Heated beams pushed the girder west 6.3”, the girder expanded, restrained, buckled, greatly deflected. The 20” sagged beams twisted the top of the girder towards them and the bottom flange away additionally >0.2”, =>6.5” , >half the 12” seat, girder fell off. Or the girder ruptured (above) since it was not restrained by the failed bolts.

Fire caused the failure of Girder 44-79, not CD.

 

[BasqueArch]

Who produced these slides? Can they be posted here?

TS' slides are his intellectual property. It's up to him who he provides them to. TS' 5 FEA slides prove him wrong. That's why he's not posting them here.
My opinion is that he's now torturing his original FEA to see if he can have it say what he wants.

 

[tsig]

NIST tells us it was 2.25 seconds or about eight stories of the fall. Please bear in mind that irrespective of any argument about columns having a minimum resistance during buckling, that there would be eight stories of mass to be accelerated by the falling upper mass if the collapse were natural. This would cause a decrease in velocity due to conservation of momentum alone. Why don't we see this?

Can you explain that?