Richard Gage Blueprint for Truth Rebuttals on YouTube by Chris Mohr

[Christopher7]

Originally Posted by chrismohr

I too agree that the NIST model did not perfectly reflect the reality of FFA for 2.25 seconds. Did it "represent the collapse with enough accuracy"? Here I disagree and say yes, it is enough accuracy

"Not perfectly" is a understatement. Their model does not fall at FFA. The draft report confirms this. Sunder admitted that "there was resistance in this case" and that free fall means "no supporting structure"/no resistance. You cannot change what he said or change the draft report.

This is critical because FFA means all the supporting structure had to have been removed in a very synchronized manner. That is the point and you know it. That is why you and the JREFers try to talk around it or say "that's close enough".

The NIST model is a progressive collapse and by definition it does not fall at FFA.

Quote:

As to my stick analogy

Despite the fact that you have no data to justify it and no legitimate reason to say it. You persist in ignoring the NIST collapse model with columns bending [not snapping like sticks] during the period of FFA.



Bazant confirms that bending steel columns provide significant resistance. He doesn't include fracturing but until he does and demonstrates that H beams weighing 500 pounds per foot can snap like sticks, saying or implying that the columns snapped like sticks is knowingly making a baseless, incorrect statement.
http://forums.randi.org/showpost.php...postcount=1050

If you are rebutting NIST and Chandler then you cannot use baseless, incorrect analogies.

Making claims that NIST does not make does not help the NIST report. It passes or fails on what they said and their draft report said, not what you or anybody here says. You may think you can explain the FFA or lack of it but that means diddly squat. We are debating whether or not the NIST report explains the FFA.

[Sunstealer]

Originally Posted by pgimeno

Oh, no, not again. Ergo, Szamboti and now Moore. Why is this concept so difficult to understand?

Mass does not vary with fragmentation. At all. Being loose might cushion the impacts somewhat, at best, but the rubble would still be able to crush floors because even with the cushioning, the increase of load would not be slow enough for it to be absorbed. [ETA: Less so if the structural elements the rubble lands on are not designed to withstand such mass. Like floors.] Just as a snow avalanche crushes a house, for example.

According to the above truthers this

YouTube Video This video is not hosted by the JREF. The JREF can not be held responsible for the suitability or legality of this material. By clicking the link below you agree to view content from an external website.

I AGREE

is impossible.

It's hilarious, they probably think a tonne of feathers is lighter than a tonne of steel.

[ozeco41]

Originally Posted by pgimeno

Yet another at #40, sorry I forgot the separator before the (**) and your text came in the wrong column.

Oops.

Too late to edit - we can live with it.

If the comment is wrong and someone criticises you for it I will 'fess up.

[GlennB]

Originally Posted by Christopher7

He doesn't include fracturing but until he does and demonstrates that H beams weighing 500 pounds per foot can snap like sticks, saying or implying that the columns snapped like sticks is knowingly making a baseless, incorrect statement.

They will "break like sticks" at the welds/bolts. Virtually every column at GZ clearly exhibited this effect. Those that bent were freak exceptions.

[Sunstealer]

C7 - what is the effect of strain rate on toughness in steels?

[Animal]

Originally Posted by Sunstealer

You may have worked with steel but your experience and knowledge of it is close to zero.

I can take a piece of steel and heat treat it so that it snaps like a stick. I can take the exact same piece and heat treat it so that it's ductile and doesn't.

Infact I can take a piece of steel and under certain conditions it will fracture in a brittle manner like a stick and in others it will bend and absorb the same force without breaking. See "ductile to brittle transition" in steels.

Stop talking out of your behind.

Agreed on all points.

Steel will bend if loading gradually exceeds it yield point, on the other hand if the loading instantaneously exceeds its ultimate failure point, it will snap.

[sheeplesnshills]

Originally Posted by Justin39640

I work with A LOT of steel and I can assure you, yes, sometimes it does. (think work hardening)

It also can snap if it is over hardened whilst heat treating.

[chrismohr]

Wow I'm overwhelmed by the responses here. Thanks so much to everyone who has answers to the chrismohr911 re-rebuttals. I will comb through it all, research a bit, etc. If anyone wants to add YouTube video links or even links to JREF posts etc., the links give people a chance to look more deeply. Alienentity and Dave Thomas and other video producers especially, if you can give me links to your videos that would be great. Let's stay with these first few dozen re-rebuttals for a week or so till I compile enough info.

[Animal]

Originally Posted by chrismohr

Wow I'm overwhelmed by the responses here. Thanks so much to everyone who has answers to the chrismohr911 re-rebuttals. I will comb through it all, research a bit, etc. If anyone wants to add YouTube video links or even links to JREF posts etc., the links give people a chance to look more deeply. Alienentity and Dave Thomas and other video producers especially, if you can give me links to your videos that would be great. Let's stay with these first few dozen re-rebuttals for a week or so till I compile enough info.

Another point against their rebuttals.......the claims about the glass breakage. The glass breakage would have occurred not only because of the explosion from the fuel, but also from the warping of the building structure by the impact of the plane. I forget how much they said the building swayed, up it could have easily overstress the glass and cause it to fracture.

[chrismohr]

Originally Posted by Sunstealer

According to the above truthers this

YouTube Video This video is not hosted by the JREF. The JREF can not be held responsible for the suitability or legality of this material. By clicking the link below you agree to view content from an external website.

I AGREE

is impossible.

It's hilarious, they probably think a tonne of feathers is lighter than a tonne of steel.

This video clip you brought up http://www.youtube.com/watch?v=FM9Fe...layer_embedded is a good example of a clear simple link to answer such objections. I'll use it in my re-re-rebuttals. Thank you.

Both my radio debate and my in-person debate with Richard Gage involved me arguing against his assertion that a building that had broken up into pieces does not lose its mass (except for the parts that are completely pulverized and float away in a dust cloud). The example I used was that I would hate to have a ton of brick pieces falling on me! I couldn't believe I even had to argue such a point. It was indeed on the level of feathers vs bricks.

[Clayton Moore]

Originally Posted by chrismohr

This video clip you brought up http://www.youtube.com/watch?v=FM9Fe...layer_embedded is a good example of a clear simple link to answer such objections. I'll use it in my re-re-rebuttals. Thank you.

Both my radio debate and my in-person debate with Richard Gage involved me arguing against his assertion that a building that had broken up into pieces does not lose its mass (except for the parts that are completely pulverized and float away in a dust cloud). The example I used was that I would hate to have a ton of brick pieces falling on me! I couldn't believe I even had to argue such a point. It was indeed on the level of feathers vs bricks.

If a ton of bricks fell on you 1/4 inch bits of you wouldn't strewn all over the place. You'd be squashed as if by Mr. Squash It All Flat.

[chrismohr]

Originally Posted by GlennB

They will "break like sticks" at the welds/bolts. Virtually every column at GZ clearly exhibited this effect. Those that bent were freak exceptions.

http://i250.photobucket.com/albums/g...vedetail-1.jpg

I am tired of this debate with Chris7 but here we go again. I do want to be clear: am I mistaken in my belief that in Building 7 many columns actually buckled according to the NIST Report? I kind of thought the columns snapping like sticks at the welded points was more common in the Twin Towers and that there were in fact many buckled columns from Building 7. Do correct me if I am wrong.

More importantly, when I used the breaking stick analogy in my video 18 (http://www.youtube.com/watch?v=2MER5PhIDt0), as I have said before, I knew and I stated in the video that the buckling columns were not identical to a breaking stick in reality. But repeated answers to my inquiries here and elsewhere make it clear that the results of breaking and buckling columns are very similar. Euler's formulae, TFK's graph, etc. all show that a buckling column loses something like 98% of its strength. Whatever vestigal resistance a fully-buckled column provides to as building's collapse can be overcome by local torquing and leveraging of the undergoing chaotic collapse and still attached in places to one another.

I ain't budging on this Chris7 because all evidence points to what I am saying as being true. And BTW we aren't even agreeing on what we are debating here. I'm debating controlled demolition vs. natural collapse. Go ahead and debate against NIST, I'm not their apologist even though I agree with most of their technical conclusions. The breaking stick analogy in my video was properly identified as such. No baseless falsehoods here. If someone could prove to me that a fully buckled column would still hold up, say, 35% of its designed load capacity, that would get my attention and we could reopen this discussion. But I look at the "buckled" column in MM's picture in the post below and there ain't much of it left at the buckling point. Much of it has snapped apart and only a small part is still holding together at all. This is just an initial observation, but I wonder if this is the case with many of the other buckled columns. Am I observing correctly that most of the column has actually snapped and not just buckled?

[chrismohr]

Originally Posted by Clayton Moore

If a ton of bricks fell on you 1/4 inch bits of you wouldn't strewn all over the place. You'd be squashed as if by Mr. Squash It All Flat.

Thank you for agreeing with me! Now please explain this to Richard Gage.

[Miragememories]

Originally Posted by Christopher7

"...Bazant confirms that bending steel columns provide significant resistance. He doesn't include fracturing but until he does and demonstrates that H beams weighing 500 pounds per foot can snap like sticks, saying or implying that the columns snapped like sticks is knowingly making a baseless, incorrect statement.
http://forums.randi.org/showpost.php...postcount=1050..."

Originally Posted by GlennB

"They will "break like sticks" at the welds/bolts. Virtually every column at GZ clearly exhibited this effect. Those that bent were freak exceptions."

Freak exceptions?

A freaky heat source and a freaky power source no doubt?










MM

[GlennB]

Originally Posted by chrismohr

I am tired of this debate with Chris7 but here we go again. I do want to be clear: am I mistaken in my belief that in Building 7 many columns actually buckled according to the NIST Report? I kind of thought the columns snapping like sticks at the welded points was more common in the Twin Towers and that there were in fact many buckled columns from Building 7. Do correct me if I am wrong.

It depends what you mean by "buckled".

Elastic or plastic buckling? And the entire column length or just each single unit within the column, given that each "column" was constructed from many separate sections? Whole columns certainly buckled but whether their elements were plastically deformed or ruptured is another matter.

NCSTAR 1-9 Vol II, searched for "failure mode", yields no reference to fracturing or bending of the bulk steel of the columns (there is probably a technical term for this, but I'm not aware of it). afaics every failure mode relates to connections.

Intuitively at least, it would seem perverse for the body of a column section to fracture when there is a weaker link such as a weld available. But you might want to get one of the heavyweight engineering types here onto that question.

I must admit I've never seen a WTC photo of any broken column section (though they might exist), just a few bent ones.

[GlennB]

Originally Posted by Miragememories

Freak exceptions?

A freaky heat source and a freaky power source no doubt?

Nobody has any idea what you're talking about.

[000063]

Originally Posted by Clayton Moore

If a ton of bricks fell on you 1/4 inch bits of you wouldn't strewn all over the place. You'd be squashed as if by Mr. Squash It All Flat.

Originally Posted by Clayton Moore

What do cement mixer trucks have to do with bone fragments found as a result of the total destruction of the three buildings on 9/11?

Originally Posted by Clayton Moore

A crushing blow does not chop its recipient into tiny pieces.

Originally Posted by Clayton Moore

WTC7 basically globally collapses into its own footprint and the discussion waddles in squirting hoses.

Originally Posted by Clayton Moore

...
The support columns had to be disabled to keep the buildings basically within their footprints when they collapsed...

Originally Posted by Clayton Moore

Jumping rope and 9/11 truth - how the sheeple have been trained to avoid unpopular truth about WTC 7

Sunday, September 25, 2011
by Mike Adams, the Health Ranger

http://www.naturalnews.com/033684_911_truth_WTC_7.html

1059Share
[Share this Article]

Quote:

...To watch the WTC 7 building fall into its own footprint,...

Quote:

...Rather, it is a question of how did all the support columns for the entire building simultaneously shatter and bring the building down at free-fall acceleration into its own footprint?...

The morons thrive on coincidence and buildings destroying themselves.

Originally Posted by Clayton Moore

If buildings could be weakened as the 9/11 buildings were said to have been on 9/11 with a total destruction into a basic footprint there would be no need for controlled demolitions.

...

First it's "in its own footprint", then its "mostly within its footprint", now it's "all over the place". I wonder if "all over the place" is "within its footprint" or "within its basic footprint". We all know that the debris field for all three buildings covered several times more ground than the building's footprint. Heck, WTC 1's collapse hit WTC 6 on its way to WTC 7. Not one, but two buildings are within its "basic footprint"?

[000063]

Originally Posted by GlennB

Nobody has any idea what you're talking about.

Including himself.

He's just nitpicking at the stick analogy, much like truthers pick at apparent "anomalies" in the Official Story because that's all they can understand. The funny thing is that the analogy is perfectly correct; when something fractures, it is a sudden loss of most of its strength. All the fancy calculations and such go right over his head, but likening a steel beam to a stick? That's clearly ludicrous.

[pgimeno]

Originally Posted by chrismohr

This video clip you brought up http://www.youtube.com/watch?v=FM9Fe...layer_embedded is a good example of a clear simple link to answer such objections. I'll use it in my re-re-rebuttals. Thank you.

Note it's also used in my #16 response as a hint on how the jet fuel descending down the elevator shaft could break the elevator doors open. Maybe I should have included an explanation as well.

[pgimeno]

Originally Posted by Miragememories

http://img210.imageshack.us/img210/5...crelic1bt5.jpg

Thanks MM. Here it is again in all its glory:

Originally Posted by Christopher7

Bazant confirms that bending steel columns provide significant resistance. He doesn't include fracturing but until he does and demonstrates that H beams weighing 500 pounds per foot can snap like sticks, saying or implying that the columns snapped like sticks is knowingly making a baseless, incorrect statement.

Given the above image, I'm entitled to call you a liar if you keep claiming it is a baseless incorrect statement. That column clearly shows fracture. The crane video clearly shows steel losing its strength after failure. The Bazant book is a study on steel behavior. A materials scientist is also pointing you to the mistakes in your assumptions.

Your only response:




ETA: This image shows clear fracture as well, most notably near the top:

[carlitos]

Originally Posted by truth guys

90,000 Liters of Jet Fuel Regardless of the volume, the jet fuel burned off within the first 15 minutes. So what is the source of the "intense heat" after that?

Originally Posted by pgimeno

The fires that the jet fuel initiated, obviously!

The inability / unwillingness of the truth people to understand this simple concept has blown me away since day one here.

• Add lighter fluid to charcoal
• Light fluid, step away from grill
• Fluid burns a bit and quickly goes away
• Charcoal gets much much much hotter over time

I mean, some of these people must barbecue, right? What the hell is wrong with their brains, that they can't see how it's the same concept? Does this TruthMakesPeace guy ever grill anything? Does nanuthermite cook his burgers?

Originally Posted by Christopher7

He says he was not given a reason FWIW.

link

Originally Posted by Darat -Administrator / JREF Forum Liaison

TruthMakesPeace has been banned. This is a ban imposed in my role as Forum Liaison and follows repeated threats by TruthMakesPeace of legal action against the Forum and the JREF.

Maybe more truth would make more peace.

[Animal]

Originally Posted by carlitos

The inability / unwillingness of the truth people to understand this simple concept has blown me away since day one here.

• Add lighter fluid to charcoal
• Light fluid, step away from grill
• Fluid burns a bit and quickly goes away
• Charcoal gets much much much hotter over time

I mean, some of these people must barbecue, right? What the hell is wrong with their brains, that they can't see how it's the same concept? Does this TruthMakesPeace guy ever grill anything? Does nanuthermite cook his burgers?




link


Maybe more truth would make more peace.

And to go along with that......is the asinine claim that since there were people standing in the openings, the fires could not have been hot enough to weaken steel.......yet 140 years ago they had this..

http://www.youtube.com/watch?v=Drsgs6-3Qlg

[Clayton Moore]

Originally Posted by 000063

First it's "in its own footprint", then its "mostly within its footprint", now it's "all over the place". I wonder if "all over the place" is "within its footprint" or "within its basic footprint". We all know that the debris field for all three buildings covered several times more ground than the building's footprint. Heck, WTC 1's collapse hit WTC 6 on its way to WTC 7. Not one, but two buildings are within its "basic footprint"?

If a ton of bricks fell on you 1/4 inch bits of you wouldn't strewn all over the place. You'd be squashed as if by Mr. Squash It All Flat.

[DGM]

Originally Posted by Clayton Moore

If a ton of bricks fell on you 1/4 inch bits of you wouldn't strewn all over the place. You'd be squashed as if by Mr. Squash It All Flat.

How high did the bricks fall from? What type of surface was I standing on?

[000063]

Originally Posted by Clayton Moore

If a ton of bricks fell on you 1/4 inch bits of you wouldn't strewn all over the place. You'd be squashed as if by Mr. Squash It All Flat.

You are not actually answering the question, I note.

Two buildings are within the "basic footprint" of WTC1?

[chrismohr]

Thanks Carlitos for the info about TruthMakesPeace. I definitely won't ask a second time!

[triforcharity]

Originally Posted by Animal

Another point against their rebuttals.......the claims about the glass breakage. The glass breakage would have occurred not only because of the explosion from the fuel, but also from the warping of the building structure by the impact of the plane. I forget how much they said the building swayed, up it could have easily overstress the glass and cause it to fracture.

You know, i've thought about this before.

Does anyone know what the requirements for the windows were? Like, code wise? How thick, how much force that can withstand, etc?

I've always been curious....

[Animal]

Originally Posted by triforcharity

You know, i've thought about this before.

Does anyone know what the requirements for the windows were? Like, code wise? How thick, how much force that can withstand, etc?

I've always been curious....

I don't have codes that go back that far

The new code calls for 110 (or 120 mph ) wind load.
Short duration laod in accordance with ASTM E 1300

It would have to be safety glazing in accordance with CPSC 16 CFR 1201

It isn't the impact loads, but the twisting and racking that would be the problem.

[Christopher7]

Originally Posted by chrismohr

But repeated answers to my inquiries here and elsewhere make it clear that the results of breaking and buckling columns are very similar. Euler's formulae, TFK's graph, etc. all show that a buckling column loses something like 98% of its strength.

Please post these formulas and graph.

[chrismohr]

Originally Posted by Christopher7

Please post these formulas and graph.

Try this:
http://forums.randi.org/showpost.php...postcount=3831
Also post 3638.
One thing on rereadiang, I think TFK said in this post that buckling is important to collapse initiation but then as collapse progressed the columns snapped? Am I reading this right? If so, then NIST's talk of collapse initiation via buckling turns into columns breaking apart at the welded connections even in Building 7? This I did not catch before, and I may be misunderstanding Tom's meaning.

[Christopher7]

Originally Posted by chrismohr

Try this:
http://forums.randi.org/showpost.php...postcount=3831
Also post 3638.
One thing on rereadiang, I think TFK said in this post that buckling is important to collapse initiation but then as collapse progressed the columns snapped? Am I reading this right? If so, then NIST's talk of collapse initiation via buckling turns into columns breaking apart at the welded connections even in Building 7? This I did not catch before, and I may be misunderstanding Tom's meaning.

Figure 12-62 shows the exterior columns buckling and providing resistance after onset of global collapse and that means during the FFA.

The buckling is over 7 floors or about 90 feet so the decent is roughly 20 feet in Fig 12-62, well into the FFA and the exterior columns are only about half way to the fully formed hinge point where they would loose an estimated 98% of their strength. That would not happen until about 80 feet into the FFA.

In other words, the NIST model is NOT falling at FFA nor are the columns snapping like sticks.

Your stick analogy is wrong because even if it did happen it would be well after the onset of FFA so what's the point?

ETA:
I watched that part again and you are using the snapping stick to explain the sudden onset of FFA.

At 4:55 you say that NIST used a video tape looking straight at the north perimeter wall as you play the CBS eye level video. This is incorrect. NIST used camera 3 at street level.

[GlennB]

Originally Posted by chrismohr

Try this:
http://forums.randi.org/showpost.php...postcount=3831
Also post 3638.
One thing on rereadiang, I think TFK said in this post that buckling is important to collapse initiation but then as collapse progressed the columns snapped? Am I reading this right? If so, then NIST's talk of collapse initiation via buckling turns into columns breaking apart at the welded connections even in Building 7?

It's certainly what he says in that post. And for a column to break anywhere other than a connection would be a very strange event as connections are easily the weakest link. If your stick had a groove cut around it that's where the eventual break would occur, as it were.

Chris7 prefers to insist on plastic buckling of the column material itself, as this allows him to claim "2% retained support" (or something) which would result in slightly < g acceleration. It's just more C7 straw-grasping to support his CD delusion.

[Christopher7]

Originally Posted by GlennB

It's certainly what he says in that post. And for a column to break anywhere other than a connection would be a very strange event as connections are easily the weakest link. If your stick had a groove cut around it that's where the eventual break would occur, as it were.

Chris7 prefers to insist on plastic buckling of the column material itself, as this allows him to claim "2% retained support" (or something) which would result in slightly < g acceleration. It's just more C7 straw-grasping to support his CD delusion.

That's not what I said at all Glenn.
The consistency of misinterpretation says a lot about the posters here.

The exterior columns were still buckling after the onset of FFA. Therefore, the NIST model is NOT falling at FFA.

[MarkLindeman]

Originally Posted by Christopher7

Figure 12-62 shows the exterior columns buckling and providing resistance after onset of global collapse and that means during the FFA.

Why does "after onset of global collapse" (in your words) mean "during the FFA"?

What Figure 12-62 says it shows is "[e]xterior column buckling after initiation of global collapse with debris impact and fire-induced damage" (i.e., a model result). The text says, "When all the exterior columns had buckled, as shown in Figure 12-62, the entire building above the buckled-column region moved downward as a single unit, resulting in the global collapse of WTC 7."

How do you conclude that 12-62 shows exterior columns providing resistance during the FFA? I find that bizarre.

Maybe you are eyeballing how far the south face has dropped in this model run at the moment of 12-62, and comparing it with the Stage 1 displacement? There would be several problems with that; maybe the easiest to understand is that the Stage 1 displacement is measured on the north wall.

[GlennB]

Originally Posted by Christopher7

That's not what I said at all Glenn.
The consistency of misinterpretation says a lot about the posters here.

The exterior columns were still buckling after the onset of FFA. Therefore, the NIST model is NOT falling at FFA.

Wrong, as MarkLindeman has idicated above. Onset of 'global collapse' is not synonymous with beginning of FFA. Except, perhaps, in your mind.

1-9 Vol II states that all exterior columns had buckled "within approximately 2 seconds" of onset of collapse. This matches almost precisely the beginning of Stage 2, as per their graphs.

While you're here - when will you open a thread to tell us your ideas on why, when and how WTC7 was CD'd?

[MarkLindeman]

Originally Posted by GlennB

1-9 Vol II states that all exterior columns had buckled "within approximately 2 seconds" of onset of collapse. This matches almost precisely the beginning of Stage 2, as per their graphs.

Glenn, just to clarify, as you know, that quotation (actually, the report doesn't spell out "seconds") refers specifically to the model result under discussion. I agree that in this respect, the model appears to agree well with the observables.

I mention this because C7 (like other people I've encountered) often doesn't seem to understand how working models are used. Basically, he seems to think that if he can find any aspect of "the NIST model" that doesn't agree with the observables, then he has rebutted "the model," ergo NIST has failed, the report is a pack of lies, etc. As you know, that isn't how serious empirical inquiry works. Certainly a model may diverge from observables to such an extent that it isn't suitable for its intended use, and/or that the underlying hypothesis is gravely infirmed or rebutted outright. Or not. That is a matter of substantive judgment. A hallmark of "truther" critiques of the NIST reports is that they don't incorporate this understanding; they stop too soon.

In one of these threads yesterday, C7 wrote something like, 'Please don't tell me that the report was close enough for government work.' Snark aside, whether a model is "close enough" is a serious and subtle question. Anyone who doesn't acknowledge that is operating at a disadvantage in serious technical discussion -- but perhaps, in some contexts, an advantage in polemic.

OK, I've exhausted my meta quota for April. I'll sit back and see whether, against all odds, I actually learn something about girders 'n' stuff.

[chrismohr]

Originally Posted by GlennB

Wrong, as MarkLindeman has idicated above. Onset of 'global collapse' is not synonymous with beginning of FFA. Except, perhaps, in your mind.

1-9 Vol II states that all exterior columns had buckled "within approximately 2 seconds" of onset of collapse. This matches almost precisely the beginning of Stage 2, as per their graphs.

While you're here - when will you open a thread to tell us your ideas on why, when and how WTC7 was CD'd?

So Glenn, Mark,

I still have questions about what Chris7 is bringing up here. First of all, it is still my understanding that NIST's draft document on Building 7 did not acknowledge freefall at all. That came into the final report, and Chris7 asserts that NIST did not change their model when they acknowledged freefall. From what I can see, Chris 7 is correct when he says this.

However, Glenn quotes NIST 1-9 (above) saying complete buckling had happened within 2 seconds of the collapse, so if I understand correctly here, the original unchanged model could allow for freefall at that point.

Now Glenn, here is where I get really confused: when you said, "And for a column to break anywhere other than a connection would be a very strange event as connections are easily the weakest link. If your stick had a groove cut around it that's where the eventual break would occur, as it were. Chris7 prefers to insist on plastic buckling of the column material itself, as this allows him to claim "2% retained support" (or something) which would result in slightly < g acceleration. It's just more C7 straw-grasping to support his CD delusion." The reason this is confusing to me is because all the NIST modeling, especially figure 12-62, shows precisely what Chris7 says happened in the NIST model, which is plastic buckling of the column material itself. Isn't that exactly what I am seeing when I look at Figure 12-62?. Look at the computer model of the view from the south around the 11th floor or so. That looks like severe, extreme, plastic buckling of the column material to me.

Lest you think I am agreeing with Chris7, I am also looking at his own post 4121 at the top of page 104. There C7 shows another set of four NIST diagrams. In these model diagrams, at 13 and 14 seconds I see plastic buckling globally in floors 7-14 and columns snapping all over the place along the east side where the penthouse has collapsed. At 15 seconds, I see columns beginning to snap along the right side. One second into the global collapse, at 16 seconds, I see more columns snapping along the right side. Two seconds into the global collapse, which would be the 17th second, there is no diagram shown by Chris7, but that may be the point at which the buckling columns are globally snapping like, dare I say it, sticks. I don't know for sure. I'm just observing what I see in these two sets of NIST computer simulations.

So the to things that seem inaccurate to me at this point are: 1) saying that Chris7 is holding onto the plastic deformation of columns assertion when in fact that is exactly how NIST modeled the collapse onset and 2) Chris7's apparently inaccurate timing of the NIST models in relation to the 2.25 seconds of freefall rates. Am I wrong here?

[GlennB]

Originally Posted by chrismohr

The reason this is confusing to me is because all the NIST modeling, especially figure 12-62, shows precisely what Chris7 says happened in the NIST model, which is plastic buckling of the column material itself. Isn't that exactly what I am seeing when I look at Figure 12-62?. Look at the computer model of the view from the south around the 11th floor or so. That looks like severe, extreme, plastic buckling of the column material to me.

I can only suggest it's more of a visual effect caused by a lot of individual elements - with limits to the resolution available - being packed into quite a small diagram, giving the impression of curves. Go back to the pdf, scale up the view to 400% or so and the curves become less apparent at the level of individual elements, and you'll notice the 'stepped' effect of small individual lines at high magnification.

While you're in there, do that search for "failure mode"

I should warn you, though, that tfk has forgotten more about these subjects than I can ever hope to know. I'd go with his statement that "Fracturing connectors takes a MASSIVELY reduced amount of energy compared to column buckling." (where he's talking about plastic buckling, I presume)

[thedopefishlives]

Originally Posted by MarkLindeman

Glenn, just to clarify, as you know, that quotation (actually, the report doesn't spell out "seconds") refers specifically to the model result under discussion. I agree that in this respect, the model appears to agree well with the observables.

I mention this because C7 (like other people I've encountered) often doesn't seem to understand how working models are used. Basically, he seems to think that if he can find any aspect of "the NIST model" that doesn't agree with the observables, then he has rebutted "the model," ergo NIST has failed, the report is a pack of lies, etc. As you know, that isn't how serious empirical inquiry works. Certainly a model may diverge from observables to such an extent that it isn't suitable for its intended use, and/or that the underlying hypothesis is gravely infirmed or rebutted outright. Or not. That is a matter of substantive judgment. A hallmark of "truther" critiques of the NIST reports is that they don't incorporate this understanding; they stop too soon.

In one of these threads yesterday, C7 wrote something like, 'Please don't tell me that the report was close enough for government work.' Snark aside, whether a model is "close enough" is a serious and subtle question. Anyone who doesn't acknowledge that is operating at a disadvantage in serious technical discussion -- but perhaps, in some contexts, an advantage in polemic.

OK, I've exhausted my meta quota for April. I'll sit back and see whether, against all odds, I actually learn something about girders 'n' stuff.

Their lack of understanding of how the models work and are used has been well-demonstrated already. I had actually intended to make a comment similar to yours, how it's completely irrational to expect a full computer simulation with best-guess estimates for inputs to match the observables perfectly. It's just not possible - similar to trying to explain to these maroons how computer modeling works or why the expectations they have are unreasonable.

[pgimeno]

Hey Christopher7, I'll try to explain it once again.

NIST just couldn't model the details of every connection with its exact failure modes. It would probably have taken many years for such a simulation to run, if it converged at all. NIST had to make concessions in order to carry out the calculation. Column resistance was an INPUT to the model, not a RESULT.

Therefore, using an incomplete model for the purpose of proving that the structural members should have provided resistance is silly. The model can't represent exactly the way the building collapsed. We know, you know, it's not an accurate representation of the collapse in all of its features.

As MarkLindeman put it:

Originally Posted by MarkLindeman

Certainly a model may diverge from observables to such an extent that it isn't suitable for its intended use,

except, in this case, its intended use is NOT to prove the resistance of the structural members, mind you. You're taking the model out of its applicability range.