'What about building 7'?

[LSSBB]

Originally pgimeno posted this (highlights added by LSSBB later):


Then LSSBB asked gerrycan this:

Now I don’t know if LSSBB was asking what solution convergence means specifically for this particular analysis, or if he was asking more generally. Either way, any Engineer (gerrycan is not an Engineer so this does not apply to him) worth his salt should have an understanding of the general concept of convergence in a mathematical sense and what that means for modeling and simulation.

Predictably gerrycan’s explanation is lacking in detail and almost cryptic:


To which LSSBB replied:

At this point the discussion should have ended as gerrycan read the article and began a journey of discovery where he learned about various topics like approximations, what convergence and non-convergence mean, infinite series, nonlinear systems, linear systems, boundary value problems, initial value problems, etc (and on and on and on).
Gerrycan should have realized that there is WAY more to these topics than what he is aware of and should have begun learning about material that Engineers are introduced to in school and then continue to learn from experience as they spend 40+ hours a week using those fundamental, foundational principles to solve problems, design things, test solutions, etc.
Instead he posted this:

LSSBB replied with:

Then gerrycan found a definition from ANSYS:


It begins to become apparent that gerrycan is now trying to find anything to word smith a reply that makes his “Load balancing the model” answer seem insightful and technically accurate.
LSSBB replies as one might expect:


LSSBB further elaborates:



Most Engineers try to use exact language (without being wordy) and to be as accurate as possible when describing something. That is why we like mathematics so much; it provides a concise, accurate way to describe something. But if you have to use words, use as many as are necessary to convey an accurate, exact meaning. Writing “Load balancing the model” falls short of that. This is what happens when non Engineers enter into discussions about technical topics they have a shallow grasp on.
Of course, gerrycan continues to attempt a defense of his position:

LSSBB explains a third time:


And then a fourth, with more detail:


After these attempts by LSSBB to educate gerrycan and encouraging him to research this topic more we get this reply from gerrycan:


Whether gerrycan is consulting with other truthers or simply investi-googling on his own I can’t say for sure, although I would suspect it is a combination of both.

Throwing out “Newton Raphson” as if he understands this method or has ever really used it in solving a problem is a desperate attempt to appear technical, mathematical, and scientific. This is a classic case of techno-babble where someone throws out technical sounding terms hoping to score some points. This particular line of discussion should have ended many posts ago. The real answer to LSSBB’s question as to whether or not gerrycan (or ziggy) understands solution convergence is “no”.

No……they don’t.

Thanks, that pretty much recaps it.

 

[Animal]

I feel the discussion has not even started, gerrycan and his team of experts which now includes Ziggi have not produced their reasons for the impossiblility they claim.

When this is done the discussion can start, they presented nothing to NIST and nothing to this forum.

If they want to be taken seriously in the real world why are they trolling here and tabloos site ?

They never will......they are only interested in "scoring points" so they can run back to their safe haven troofer forums and claim "victory" These are not the quotes of people trying to debate, learn nor sway opinion. This exercise is solely so they can chest thump to their fellow troofers.

It should be, after all, you guys are so far getting it handed to you collectively from one guy, who you suppose may be a team.
Goodness only knows what would happen if you guys came up against that team. Fancy finding out?

You have no agreeable authority left to appeal to, so you try to attack the authority of those who oppose you.
Kinda desperate that.

I think you're being a bit hard on Pgimeno there.

Ahhh, Jay the FEA expert. Did you like my description "load balance" ?

You and others that tried to pass off the false column displacement and the false leverage story in a matter of fact manner as NIST´s conclusions. Some people here fabricated these strawmen and passed them off as NIST´s work, and then you ridiculed gerrycan for not including them in his assessment of the 6.25 inch displacement.

Without these made up fantasies, you are again stuck with what NIST actually says caused the walk off: the expansion of those floor beams.

I already did, he just wasn't paying attention, and neither are you.
You should be lapping this stuff up Jay, after all, you are a self proclaimed expert in this stuff, claiming that others on here are "lay" as opposed to you being the consummate pro engineer.
Time to speak up Jay, no more hiding.

This isn't a quiz Jay, and even if it were, you wouldn't be asking the questions, so stop trying to officiate and PLEASE stop trying to get me to answer trick questions from your buddy.
Pathetic.

 

[Ape of Good Hope]

They never will......they are only interested in "scoring points" so they can run back to their safe haven troofer forums and claim "victory" These are not the quotes of people trying to debate, learn nor sway opinion. This exercise is solely so they can chest thump to their fellow troofers.

This sort of thing hardly helps:

http://www.internationalskeptics.com/forums/converse.php?u=42340&u2=69674


Stay classy, truthers.



ETA - there were originally two visitor messages in the link, the second of which has since been removed.

 

[Crazy Chainsaw]

Playing games is all truthers can do,
when the graduate from low hanging fruit to fallen rotting
Nuts.
I see absolutely no critical thinking in Cters
Post in this thread. They seam to be promoting the
Theory false that The paint chips would have been
Used to cause rapid heating inducing failure and mimicking.a
Natural collapse.
An evolution theory simular to greening thermal
Weakening theory using AP.
No evidence however is avaliable to prove
The magic paint has any.sugnificancy to any
Discussion of the collapses.

 

[Crazy Chainsaw]

Playing games is all truthers can do,
when the graduate from low hanging fruit to fallen rotting
Nuts.
I see absolutely no critical thinking in Cters
Post in this thread. The seam to be promoting the
Theory false that The paint chips would have been
Used to cause rapid heating inducing failure and mimicking.a
Natural collapse.
An evolution theory simular to greening thermal
Weakening theory using AP.
No evidence however is avaliable to prove
The magic paint has any.sugnificancy to any
Discussion of the collapses.

 

[MileHighMadness]

Well...I can got my answers...gerrycan knows nothing about ANSYS or FEA modeling or design.

 

[pgimeno]

The East displacement, if it did occur, happened AFTER the girder failed.

That's ridiculous. The expansion doesn't take an instant. It probably was still expanding when the girder walked off.

Anyway, are you then admitting that if it happened BEFORE, that would have enabled the girder to walk off due to displacement of the column?

Is that your position?

(To start with, you have no proof of your assertion, and yours is as good as mine that it happened BEFORE. But I want to be absolutely clear on that point.)

It's very important, because, well, let's assume for a second that you were right and that the displacement of the column started after the girder failed. In that case, the issue is just a matter of the order of things and the fire intensity at certain spots at certain times, but it would be basically proven that, regardless of whether NIST got it right or not, WTC7 could indeed collapse due to fire, and therefore your concern:

I am open to any explanation as to how wtc7 collapsed. As it stands there is not a reasonable explanation for how fire could initiate it and it remains therefore possible that it was brought down with explosives.

should no longer be a concern, and you have reasons to be happy. Also, since it wouldn't change the rest of the report in any way, NIST's conclusions would stand.

 

[LSSBB]

They never will......they are only interested in "scoring points" so they can run back to their safe haven troofer forums and claim "victory" These are not the quotes of people trying to debate, learn nor sway opinion. This exercise is solely so they can chest thump to their fellow troofers.

http://en.m.wikipedia.org/wiki/Counting_coup

 

[pgimeno]

This is not about probabilities, this is about what NIST actually concludes in the report having itself assessed its own data and "probabilities," and that conclusion was to NOT specify the column displacement as a factor in the walk off event.




I already asked the source and the report´s conclusion is to not specify the column displacement as a factor in the walk off. "Making sure" is something you should have done before you claimed as a FACT that this column displacement was a factor in the walk off.




The flaw in the report is obvious: it does not give evidence for the possiblity of the alleged 6.25 inch displacement. And you obviously noted this flaw yourself because you went out "looking for ways in which ANSYS could have showed walk off as NIST reports it did."

But instead of just accepting the problem you made up a remedy to the flaw and passed it off as NIST´s story. Your leverage story was not a way in which the ANSYS "could have" shown walk off because it is based on assumptions that contradict NIST´s data, namely that the beams were still connected to the girder so that this phenomenon you claimed was in fact impossible according to NIST´s data.



You and others that tried to pass off the false column displacement and the false leverage story in a matter of fact manner as NIST´s conclusions. Some people here fabricated these strawmen and passed them off as NIST´s work, and then you ridiculed gerrycan for not including them in his assessment of the 6.25 inch displacement.

Without these made up fantasies, you are again stuck with what NIST actually says caused the walk off: the expansion of those floor beams.

On the other hand, I'd be interested in watching how you address JayUtah's questions. I'll give you time to address them.

And I asked you to be more specific about "data and numbers." Give us a roadmap for how real engineers would have solved this problem in a different (and presumably more scientific) way. And maybe some examples of how real engineers have solved it differently (and presumably more scientifically) elsewhere, so we know your insistence has actual merit. Your inability to do so -- nay, your continued disinterest in even acknowledging that those questions were asked of you -- seems to be indicating that you want to impose a standard of evidence without being quizzed too hard on whether it's a good one.

As I said, this thread and the related ones in this subforum contain a discussion on the methodologies used. You say you're not interested in "pet theories," but unfortunately you've fallen into the trap of blatantly demanding only one kind of answer, without regard for whether it's the right kind of answer. That has the effect of begging the question. You want your blustery denials to be seen as some kind of intellectual victory, but you're not participating in the intellectual exercise with more than a semblance of interest.

 

[Animal]

Well...I can got my answers...gerrycan knows nothing about ANSYS or FEA modeling or design.

It took you that long?

 

[JayUtah]

...with an eye to some larger comprehensive theory.

That's a pretty optimistic hope. It's been more than a decade. The 9/11 conspiracy theorists prosecute their case in exactly the same manner as every other conspiracy theorist ever had, using arguments that are all too familiar to, again, every other conspiracy theory. It's about scoring meaningless rhetorical points by appearing to best whoever will engage them in their silly games. I do sympathize with your sentiment, but I think you're barking up the wrong tree if you ever hope to get an actual credible alternative, affirmatively argued, and defensibly sustained.

 

[Dave Rogers]

Yeah, if I wanted the kind of education that teaches that attaining satisfactory convergence in ANSYS has nothing to do with load balance I would have came here.

Since there's obviously nothing else of interest in gerrycan's posts, perhaps someone could clarify exactly which logical fallacy this is. Gerrycan stated that "model convergence" meant "load balancing the model", has had it explained to him that load balancing is the means of determining in this particular instance whether model convergence has occurred but is not itself synonymous with model convergence, and is now characterising this response as "attaining satisfactory convergence in ANSYS has nothing to do with load balance". Of course, it's a non sequitur, but so are all formal logical fallacies; I just wondered whether it fell into any other specific class, but I'm having trouble unpicking it.

Dave

 

[Hellbound]

Since there's obviously nothing else of interest in gerrycan's posts, perhaps someone could clarify exactly which logical fallacy this is. Gerrycan stated that "model convergence" meant "load balancing the model", has had it explained to him that load balancing is the means of determining in this particular instance whether model convergence has occurred but is not itself synonymous with model convergence, and is now characterising this response as "attaining satisfactory convergence in ANSYS has nothing to do with load balance". Of course, it's a non sequitur, but so are all formal logical fallacies; I just wondered whether it fell into any other specific class, but I'm having trouble unpicking it.

Dave

Seems a classic strawman to me. Make a caricature of your opponants argument by exaggerating or simplifying it, and argue against that instead of the actual argument.

 

[Dave Rogers]

Seems a classic strawman to me. Make a caricature of your opponants argument by exaggerating or simplifying it, and argue against that instead of the actual argument.

That's part of it, certainly, but there's at least a hint of claiming that the opponent is denying the antecedent in the way the strawman is constructed; he seems to be equating a statement that load balancing is not synonymous with model convergence to one that load balancing is unrelated to model convergence.

Maybe it's a bit of a hobby-horse of mine, but I quite enjoy the study of precisely expressed illogic.

Dave

 

[WilliamSeger]

[FONT=&quot]1) [/FONT][FONT=&quot]NIST analyzes the northeast corner floor system to evaluate its response to elevated temperatures and to confirm which failure modes need to be accounted for in the 16-story and 47 stories models.[/FONT]​

[FONT=&quot] [/FONT]​

[FONT=&quot] “A finite element analysis of the northeast corner floor system was conducted to evaluate its response to elevated temperatures and to confirm which failure modes needed to be accounted for in the 16-story ANSYS model. ….. This analysis demonstrated possible failure mechanisms that were used to develop the leading collapse hypothesis further. The failure modes in this model were incorporated into the 16 story ANSYS and 47 story LS-DYNA analyses.[/FONT][FONT=&quot] (Section 8.8 pp.349,353)[/FONT]
[FONT=&quot]
[/FONT]​

[FONT=&quot]2) [/FONT][FONT=&quot]NIST determines C79-44 failed by lateral-torsional buckling in the one story and 16 story models.[/FONT]​

[FONT=&quot]Here is a paraphrased version of the most detailed explanation of how NIST described the failure of girder C79-44 for a one floor model in their report (NCSTAR 1-9, section 8.8, their pp. 349-354):
The expanding beams pushed the C79-44 girder to the west. The expanding girder jammed at C79 and C44. The beams continued to expand and were axially compressed by the resisting girder, buckling the beams. The sagging beams rotated the heated, buckled girder to the east. (See Figures 8-26, 8-27). At a certain rotated critical angle of the top flange, the girder failed to carry its load and fell. (Section 11.2.9, pp.487-488)[/FONT]
[FONT=&quot]“Axial compression then increased in the floor beams, and at a beam temperature of 436 °C, the northmost beam began to buckle laterally. Buckling of other floor beams followed as shown in Figure 8–27 (a), leading to collapse of the floor system, and rocking of the girder off its seat at Column 79 as shown in Figure 8–27 (b)”[/FONT][FONT=&quot] (p. 353) See Figures 8-27(a,b).[/FONT]
[FONT=&quot]“If a beam or girder twisted half of its flange width laterally, it would not be able to support its gravity loads and would be removed from the analysis. “ [/FONT][FONT=&quot]In this girder case half of the W30x133 flange width = 5.25”[/FONT]
[FONT=&quot]
It should also be noted that whereas the attention has been focused on the seat at C79, this unrestrained girder condition at this seat was of an area of a few square inches whereas the twisting forces on the girder occurred over the entire ~44 foot girder, failing it as NIST noted in their lateral- torsional buckling analysis and figures.[/FONT][FONT=&quot][/FONT]

​

[FONT=&quot]3) NIST uses the one floor model findings in the 16 floor model section 11.4.1 and determines C79-44 failed by buckling.[/FONT]​

[FONT=&quot] “Thermal Effects on Floor Beams and Girders[/FONT]​

[FONT=&quot]The girder between Columns 26 and 81 buckled and walked off the bearing seat between 3.25 h and 3.5 h. In a similar fashion, the girders between Columns 79 and 80 and Columns 80 and 81 buckled and the girder between Columns 44 and 79 buckled and walked off the bearing seat between 3.7 h and 4.0 h. Girder buckling was due to the combined effects of (1) gravity loads from the floor beams, (2) lateral westward displacement due to the thermal expansion in the east floor beams, and (3) increased axial loads due to thermal expansion in the girder. “(p.527)[/FONT]

[FONT=&quot][/FONT][FONT=&quot][/FONT]
[FONT=&quot]4) [/FONT][FONT=&quot]In light of the buckled girder failure, how then is the following consistent?[/FONT]
[FONT=&quot][/FONT]
[FONT=&quot][/FONT]​

[FONT=&quot] “Thermal Effects on Connections for Floor Beams and Girders[/FONT]​

[FONT=&quot]Walk off occurred when beams that framed into the girders from one side thermally expanded and the resulting compressive forces in the beams pushed laterally on the girder from one side, sheared the bolts at the seated connection, and then continued to push the girder laterally until it walked off the bearing seat. A girder was considered to have lost vertical support when its web was no longer supported by the bearing seat. The bearing seat at Column 79 was 11 in. wide. Thus, when the girder end at Column 79 had been pushed laterally at least 5.5 in., it was no longer supported by the bearing seat.“[/FONT][FONT=&quot](p.527)[/FONT]
[FONT=&quot]
[/FONT]​

[FONT=&quot]The failure of the girder by buckling is clear. Is this second explanation consistent with the buckling mode?[/FONT]​

[FONT=&quot]a) [/FONT][FONT=&quot]The beams continued to push laterally in both explanations.[/FONT]​

[FONT=&quot]b) [/FONT][FONT=&quot]The girder lost vertical support when the web was no longer supported by the bearing seat in both explanations.[/FONT]​

[FONT=&quot]c) [/FONT][FONT=&quot]The girder end at Column 79 had been pushed laterally at least 5.5” (half the buckling flange failure lateral distance from vertical was 5.25”) in both explanations.[/FONT]​

[FONT=&quot]d) [/FONT][FONT=&quot]The girder was no longer supported by the bearing seat in both explanations.[/FONT]​

[FONT=&quot] [/FONT]
[FONT=&quot]
[/FONT]​

[FONT=&quot]5) [/FONT][FONT=&quot]NIST is right, fire not explosives caused the collapse of WTC7[/FONT]​

[FONT=&quot] [/FONT]​

[FONT=&quot][/FONT]​

[FONT=&quot] [/FONT][qimg]http://img208.imageshack.us/img208/8979/figure827.jpg[/qimg]​

​

Yay. Show some models where NIST got the crucial connection totally wrong... That'll help.

Limp, unimpressive reply.

It was more than was warranted.

[qimg]http://www.internationalskeptics.com/forums/attachment.php?attachmentid=32620&stc=1&d=1425431431[/qimg]

Does this look like the column 79 girder connection to you, or does it look more like column 81 ?

Well, no, that was certainly not "more than was warranted"; it was thoroughly inadequate unless you're conceding the point. If BasqueArch's paraphrasing of NCSTAR 1-9, section 8.8 is accurate, then the "walk-off" description used in the 16-floor model is just a Readers Digest version of how they arrived at that failure mode. So for starters, do you agree, disagree, or have no comment on what section 8.8 actually says? If you disagree, then please provide your own interpretation. If you agree, then that is the NIST explanation that should deserve focus rather than the simplified walk-off version.

(That would also seem to satisfy Ziggi's request for details about what the report says, so hopefully he will now proceed to making a point.)

 

[gerrycan]

When NIST were confronted with the fact that they needed to somehow move the expansion from 5.5 to 6.25", they had to release an erratum statement to that effect. If they explicitly believed that an additional factor was expansion of the C76-79 pushing the column east wasn't that statement the place to specify that?

 

[WilliamSeger]

When NIST were confronted with the fact that they needed to somehow move the expansion from 5.5 to 6.25", they had to release an erratum statement to that effect. If they explicitly believed that an additional factor was expansion of the C76-79 pushing the column east wasn't that statement the place to specify that?

That's nowhere near answering what I asked.

 

[Dave Rogers]

When NIST were confronted with the fact that they needed to somehow move the expansion from 5.5 to 6.25",

Now that one is definitely poisoning the well. Classic example.

Dave

 

[gerrycan]

That's nowhere near answering what I asked.

I'll try to answer it later. Still think what I said was pertinent though

 

[jaydeehess]

Correct! Thank you for your humble and sharp observation. Chapter 11 of NIST´s report on Building 7 only says that this displacement of column 79 happened in the 3.7 to 4 hour slot of the simulation, and chapter 11 says elsewhere that the 44-79 girder walked off the seat during this same general time slot.

In reality NIST states that these time periods had a begin time separated by 12 minutes.

This has given the impression that the displacement of the column could have aided the walk off event, but NIST does not actually say that, anywhere. And more specifically, when you read the summary of the walk off event in chapter 11, you will see that NIST does not specify this displacement of the column as a factor in the walk off event.

Neither do they say it did not contribute to walk off. However, given that movement of girder between col79-44 is a few hundred percent more than cvol displacement, the obvious explanation for this is that NIST concentrated on the most prominent factor in walk off. One other reality and experience based observation is that gross failure in complex systems is rarely due to a solitary event.

The most obvious explanation is that the 44-79 girder walks off the seat before the column is displaced

Really? They also do not specifically state that column displacement was a factor in col buckling. In fact they don't mention it again. Why even bother mentioning it if its not,supposedly, a factor in either girder walk off(in which discussion the description happens to be) , nor in col 79 buckling?
So, no, the most obvious explanation, given location of that discussion and mentioning it at all, something called context, indicates that it was a secondary factor in girder walk off.

Gerrycan seems to have another explanation for why NIST did not specify this as a factor in the walk off scenario. I don´t know which one is correct, but that is not really the main issue. All we have to know is that this column displacement was not a factor in the walk off according to NIST.

You must KNOW that by reading between the lines, lines you conveniently separate from context. Neither you or Gerrycan has an explanation as to why its mentioned in the first place. Are there not a lot of structural movements not specifically described in the text? Yet here's one that is and you two automatically , and without regard to context, dismiss it.