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Tags 9/11 , ANSYS , collapse initiation , collapse model , fea , nist , wtc7

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Old 28th December 2015, 11:12 AM   #1
Oystein
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Collapses: Fire Alone?

NIST-reports - decrypted version from which you can copy&paste can be found here:
https://onedrive.live.com/?id=23638D...638DA582FECBF6
(Thanks to MrKoenig from The911Forum.)


The short story of the NIST's collapse initiation is that the fire-induced failure of G79-44 on floor 13 triggered progressive floor collapses, leaving column 79 critically unbraced.

NIST arrived at this by the following sequence of models and their results:
  1. They modeled fire progression through floors 5-16 to get a couple of heating regimes
  2. They applied those heating regimes to a 16-story model in ANSYS
  3. ANSYS
  4. They found that fire Case B best fit observations
  5. After 4 hours of Case B fires, ANSYS had identified which girders, beams and connections were damaged and failed
  6. In a separate LS-DYNA model of 47 floors, they first applied gravity loads, then external damage, then temperatures prevalent after 4 hours of the ANSYS model, then, suddenly and at the same time, all damages that ANSYS found.
  7. Girder and beam connections determined to have "failed" started to fall in that model.
  8. The dynamic impact of falling masses on floors below was computed by LS-DYNA and found to punch out floor slabs below, such that after a few seconds, column 79 (and 80, 81) were unbraced over several stories and failed
  9. Total progressive collapse followed.

Now everybody always focuses on the G79-44 girder on floor 13, that "walked off" to the west, in NIST's story, being pushed off its seat by epanding secondary beams to its east.
Much debate ensues over whether such a "walk off" to west is plausible, with ARUP finding a "pull off" to either east or north plausible as well, and Truthers denying whatever they can.


BUT

What everybody seems to be ignoring is that this G79-44 girder on floor 13 wasn't the only girder or beam falling!

NIST also reports on a failure on the 14th floor of the connection of the G77-80 girder at column 79, which fell onto floor 13 and also apparently cascaded down.

To verify this is true, turn to Figure 11–36 of NIST NCSTAR 1-9 (see link at the beginning of the post) on page 512 (p578 of the PDF):

Column 80 is the center column of the three right-most core columns, and the G77-80 girder is the one to its left (west). Its connection on column 80 is drawn as a black dot, black meaning it has failed completely. The girder is drawn red, meaning it has lost vertical support. The secondary floor beams extending to both sides (north and south) are also drawn red, as their vertical support depends on G77-80 being vertically supported, which it isn't.

The LS-DYNA model starts running at a time t=0 without loads and damages. During the first 8.5 seconds, NIST applies gravity, external damage and temperatures and allows for the structure to settle. This is described in Section 12.3.2 on page 563 (p629 of the PDF) and following.

Then, at 8.5 s, NIST applies all the Case B fire damage that ANSYS determined after 4 h (Section 11.3.2, start at page 503), to the LS-DYNA model.
Failed connections are let fall.

Figure 12-42 shows the result at 9.5 seconds - 1 s later:

Note that this Figure shows floor structures from both floor 13 and floor 14 dropping on the respective floor below inside the area circled red on the right.

Figure 12-43 then shows the situation another 6 seconds later:

(Note that this image is only a PART of Figure 12-43 - the rest of the Figure has plots with the vertical stress and displacement of columns 79, 80 and 81).

In this image, the floor failures on floor 13 and floor 14 have already reached floor 5.


I am wondering:
  • What if only floor 14 had collapsed - or had collapsed ahead of the floor 13 G79-44? Could this have triggered the fl13 G79-44 collapse even if that girder had not walked off?
  • Has NIST, or anyone, considered this?
  • Is that a scenario that we could ask Dr. Hulsey to check out?
  • How appropriate was if of NIST to let all ANSYS failures occur at the same time in LS-DYNA, given that they most likely would have occurred at different points in time?
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Old 28th December 2015, 03:06 PM   #2
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Good summary Oystein. Three comments only - plus one example. Process comments only - I agree with your technical content:
Originally Posted by Oystein View Post
Now everybody always focuses on the G79-44 girder on floor 13, that "walked off" to the west, in NIST's story, being pushed off its seat by epanding secondary beams to its east.
Much debate ensues over whether such a "walk off" to west is plausible, with ARUP finding a "pull off" to either east or north plausible as well, and Truthers denying whatever they can.
Yes - because T Szamboti framed his claims with that limitation - the false focus on the single issue out of context. And most debunkers are content to focus on rebutting claims BUT limiting themselves to the false framework set by the truther. A guaranteed recipe for going in circles when the debunkers agree to disregard the multiple fatal errors in order to play the game as defined by the truthers. (Military version "Avoid fighting on the ground chosen by the enemy" ) Note the recent hundreds of posts (?) by gerrycan aimed and mostly successful at keeping the discussion within the false range of details he wants AND overlooking the false premises of logic he builds on.

For the EXAMPLE - and the inevitable same example in two guises. Missing Jolt - where true to his SOP Tony made false assumptions - the relevant jolt could NEVER happen yet debunkers were content to accept the false premise and go looking for jolts - even arguing to support T Sz that littler jolts still somehow qualified. (And "tilt causes/prevents axial impact" is the same error in genetic form. Another one where debunkers were prepared to stay within the false context set by the truther - usually T Sz on that occasion also. Debunkers argued the maths of a coming future event - the impact - WHEN at the starting point of the argument the event was already past history - the column ends had already missed.)

Originally Posted by Oystein View Post
What everybody seems to be ignoring is that this G79-44 girder on floor 13 wasn't the only girder or beam falling!
Way back when Tony Szamboti first posted his WTC nonsense I "called him on three points - in order:
1) His assumption of "pristine" i.e. assumption that the column had not moved. I asserted that until he proved his assumption his claim was "Not proven" I did not bother "rebutting the claim - merely pointed out that it was not supported.
2) His false single focus on "girder walk-off" when Col 79 HAD failed and MUST have lost multiple layers of support;
3) His higher order false claims including the nonsense that if NIST is wrong on one detail the whole of their hypothesis is rebutted. Note that gerrycan and T Sz still persist with that nonsense.

There are several reasons why those foundation errors do not get discussed. The main one being that those of us - me and a couple of others - who identify the foundation errors simply do not bother debating the irrelevant issues of details. Whilst many members enjoy "whack a mole" as a pastime. And some try to use demonstration of errors of detail to lead back up to a more valid framework of argument. Reality is that gerrycan's claims have long descended into trolling.

Originally Posted by Oystein View Post
I am wondering:
  • What if only floor 14 had collapsed - or had collapsed ahead of the floor 13 G79-44? Could this have triggered the fl13 G79-44 collapse even if that girder had not walked off?
  • Has NIST, or anyone, considered this?
  • Is that a scenario that we could ask Dr. Hulsey to check out?
  • How appropriate was if of NIST to let all ANSYS failures occur at the same time in LS-DYNA, given that they most likely would have occurred at different points in time?
I would recommend getting clear what the objective is AND who are the target group(s) for the proposed effort. Two obvious ones are -
(1) trying to persuade truthers which I suggest is a lost cause; and
(2) "doing it for scientific curiosity" is valid but of little 9/11 relevance e.g. discussing thermXte does not interest me and others of like mind in the context of 9/11 where there was no CD.

Last edited by ozeco41; 28th December 2015 at 03:41 PM.
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Old 28th December 2015, 03:57 PM   #3
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Originally Posted by ozeco41 View Post
...
I would recommend getting clear what the objective is AND who are the target group(s) for the proposed effort. Two obvious ones are -
(1) trying to persuade truthers which I suggest is a lost cause; and
(2) "doing it for scientific curiosity" is valid but of little 9/11 relevance e.g. discussing thermXte does not interest me and others of like mind in the context of 9/11 where there was no CD.
Objective:
  • Understand the NIST report better
  • Understand and discuss NIST's methodology analysing simulations designed to match observations to a reasonable degree in relevant features
  • Alert members of a "detail" of the NIST report that probably is news to most, and discuss what can be made of it
  • Defocus the old G79-44 girder
  • Perhaps come up with proposals for further studies, e.g. addressed at Dr. Hulsey
Target group:
  • The able engineering minds here
  • I had considered writing explicitly that this might include gerrycan, despite his trolling and his agenda, but would definitely exclude TSz, who has today and yesterday displayed a shocking degree of engineering disability (I truly believed, and wrote several times, that he is a blunt and shameless liar, but it has started to dawn on me in his latest posts that perhapse he really is entirely incapable of reading for comprehension and understanding an engineering report)
  • Anyone interested in learning a bit more about the logic and the results of the NIST report

The bulleted list "I am wondering" was meant as suggestions on what to make of this finding (new to me) that NIST's simulations had not only one critical girder starting a cascading vertical collapse progression but (at least) two.
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Old 28th December 2015, 04:26 PM   #4
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Understood.

I'm tempted to fine tune with my usual pedantry --- but I'll resist -- you define a good starting point and issues needing clarification will emerge.

I suggest the sooner or later some mapping of the "taxonomy" of the issues will be needed. At the simplest (and it isn't simple) the NIST reports have to be seen in some sort of full context. (e.g. did NIST go easy on the issue of sub standard not up to code design would demand recognising the overall socio-political context.) But by all means try for technical only.

The technical context (draft version 0.01)
Top Level.
1) WTC 7 collapsed on 9/11 2001
2) Only two claims as to causes:
(a) Fire effects alone; OR << Status - default hypothesis
(b) Assistance of MHI AKA "CD" << Status - claimed by truth movement. No valid hypothesis presented.
3) Range and status of hypotheses
(a) NIST is the main official version. << The TOPIC - Status no extant professional disagreement on the significant points. Some acknowledged differences at detail level. None affecting main points of NIST.
(b) Many bits of fragmented truther claims for CD - none requiring serious discussion and no truthers prepared to engage in valid reasoned arguments. ( Oystein - your challenge to gerrycan fits in "(a)" - not here - if he wants to present a CD hypothesis it does not fit in this initiative until he proves it to prima facie. And I agree Tony has worn out his welcome.)
(c) Other hypotheses which support NIST at significant higher levels - differ at insignificant details. Status if needed would require defining "significant" and testing some of the differences - again "If needed" - I think it is outside your objective "Understand NIST"


HOWEVER:
RL intervenes - "The grass is riz - I wonder where the mower is?"

And the edge trimming tools - I know - in the shed.....

Last edited by ozeco41; 28th December 2015 at 04:29 PM.
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Old 29th December 2015, 01:07 AM   #5
Oystein
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Originally Posted by ozeco41 View Post
...
The technical context (draft version 0.01)
Top Level.
1) WTC 7 collapsed on 9/11 2001
2) Only two claims as to causes:
(a) Fire effects alone; OR << Status - default hypothesis
(b) Assistance of MHI AKA "CD" << Status - claimed by truth movement. No valid hypothesis presented.
2(b) doesn't exist as a published, debatable hypothesis, so it cannot be part of the technical context here.

Originally Posted by ozeco41 View Post
3) Range and status of hypotheses
(a) NIST is the main official version. << The TOPIC - Status no extant professional disagreement on the significant points. Some acknowledged differences at detail level. None affecting main points of NIST.
(b) Many bits of fragmented truther claims for CD - none requiring serious discussion and no truthers prepared to engage in valid reasoned arguments. ( Oystein - your challenge to gerrycan fits in "(a)" - not here - if he wants to present a CD hypothesis it does not fit in this initiative until he proves it to prima facie. And I agree Tony has worn out his welcome.)
(c) Other hypotheses which support NIST at significant higher levels - differ at insignificant details. Status if needed would require defining "significant" and testing some of the differences - again "If needed" - I think it is outside your objective "Understand NIST"
3(b) must be limited by the extant truther claims about how different FEAs with different starting conditions yield different detail results and what this supposedly can be spun to - if any truthers want to bring this up, fine - but there is no need to debate this at all, we know from the other threads how that fails.

I'd frame the technical context thus:
  • All the extant collapse hypotheses that are a) examined by FEA and b) have falsifiable technical details agree that fires caused the failure of beam and girder connections around columns 79-81, resulting in column buckling to start global collapse
  • These hypotheses, together have come up with various plausible detail mechanisms to account for these girder failures, such as:
    • Push-off by expanding contributory beams on floor 13 (NIST) while heating
    • Pull off to the east or north on floor 10 or 13 (ARUP, Nordenson) while cooling
    • Torque-off while heating on floor 13 (ARUP)
    • Failure in tension on floor 14 as corresponding, expanding girders below pushed the column out of plumb (NIST)
  • The first mechanism has been at the forefront of the technical debates for years. The next two came to our collective consciosness and attention in recent days when benthamitemetric bought them and posted them at Metabunk. We are discussing them in threads of their own. The last detail, I think, has so far been overlooked by most or all; I found it and brought it up in response to a question by TSz, and think it deserves its own thread, seeing that the other detail mechanisms have their own threads, too.
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Old 29th December 2015, 01:35 AM   #6
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Originally Posted by Oystein View Post
2(b) doesn't exist as a published, debatable hypothesis, so it cannot be part of the technical context here.
Agreed.

Originally Posted by Oystein View Post
3(b) must be limited by the extant truther claims about how different FEAs with different starting conditions yield different detail results and what this supposedly can be spun to - if any truthers want to bring this up, fine - but there is no need to debate this at all, we know from the other threads how that fails.
Agreed also. Which brings us to the weakness of all this 9/11 discussion - there are no truther claims worthy of discussion EXCEPT that "debunkers" have historically accepted and continue to accept "burden of DISproof". Which puts us in the bind I (we?) have identified many times. There aint nothin worthy of discussion in the domain of "conspiracy". The engineering mechanics is of interest but.....

However :
Originally Posted by Oystein View Post
I'd frame the technical context thus:
  • All the extant collapse hypotheses that are a) examined by FEA and b) have falsifiable technical details agree that fires caused the failure of beam and girder connections around columns 79-81, resulting in column buckling to start global collapse
  • These hypotheses, together have come up with various plausible detail mechanisms to account for these girder failures, such as:
    • Push-off by expanding contributory beams on floor 13 (NIST) while heating
    • Pull off to the east or north on floor 10 or 13 (ARUP, Nordenson) while cooling
    • Torque-off while heating on floor 13 (ARUP)
    • Failure in tension on floor 14 as corresponding, expanding girders below pushed the column out of plumb (NIST)
  • The first mechanism has been at the forefront of the technical debates for years. The next two came to our collective consciousness and attention in recent days when benthamitemetric bought them and posted them at Metabunk. We are discussing them in threads of their own. The last detail, I think, has so far been overlooked by most or all; I found it and brought it up in response to a question by TSz, and think it deserves its own thread, seeing that the other detail mechanisms have their own threads, too.
Agreed.
PLUS - don't overlook that some members here - Basquearch being one - have explained the failure of the girder in very persuasive terms. Apart from the more basic issue that I stop at for WTC 7 - T Szamboti as the main leader on the opposition to girder walk-off a la NIST has not proven his starting assumptions. So his claim is "not proven" on that basis and probably "disproven" by a number of detail level rebuttals.

HOWEVER we are accepting the need for discussion of the technical issues when there is no need for discussion:
(a) in the absence of a valid discussable pro CD hypothesis. That is the level of the issues taxonomy at which truthers could have a valid case to make. All their lower level details nonsense lacks validity absent a legitimate objective of claim - which is the foundation issue that gerrycan specifically rejected when I challenged him on it around 8 December;
(b) UNLESS the purpose of discussion is "scientific" (actually engineering forensic) curiosity.

And you know me well enough - "(b)" is of more interest to me than thermXte in dust because it is more directly related to understanding of WTC collapses - which are directly related to rebuttal of CTs about CD.

Last edited by ozeco41; 29th December 2015 at 01:37 AM.
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Old 29th December 2015, 01:43 AM   #7
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Originally Posted by ozeco41 View Post
...
HOWEVER we are accepting the need for discussion of the technical issues when there is no need for discussion:
(a) in the absence of a valid discussable pro CD hypothesis. That is the level of the issues taxonomy at which truthers could have a valid case to make. All their lower level details nonsense lacks validity absent a legitimate objective of claim - which is the foundation issue that gerrycan specifically rejected when I challenged him on it around 8 December;
(b) UNLESS the purpose of discussion is "scientific" (actually engineering forensic) curiosity.
And (b) it is.
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Old 29th February 2016, 01:58 PM   #8
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The girder walk off party was looking for THE straw that broke the camel's back.. or as the Truth guys claim... no way Jose did it happen or could it trigger the break the camel's back.

The fact is... as Ozzie mentions and often eludes to... the buildings' structural frasmes... were under all manner of stress and the "degradation" was progressing in multiple yet connected... as the structure acts as a composite... ways.

It is simply absurd to look at one girder... one connection when the entire building has been on fire for 7 hours. And this is why I simply don't bother with these girder 44-79 on floor 13 debates. WOT waste of time.

It's more than likely that the computer modeling can handle all the nodes and complexity especially without real time data to drive the model.

The structure was slowly losing its integrity and reach ONE MOMENT in time when it tipped passed stability into unstable and began to rapidly collapse.. it has passed the point of no return.
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Old 8th March 2016, 10:28 AM   #9
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Mod WarningThis is what was salvaged at the first attempt at this topic. Do not go off topic again. Keep it civil, keep it on topic. The topic is not the other posters.
Responding to this mod box in thread will be off topic Posted By:kmortis
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