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reprehensor Donating Member (1000+ posts) Send PM | Profile | Ignore Fri Aug-25-06 06:09 AM
Original message
Structural Engineer doesn't buy "official" WTC collapse theory
On the Thursday, August 24, 2006 broadcast of Prof. James Fetzers (co-founder, ST911) Non-Random Thoughts radio program, he had a surprise guest; a Structural Engineer with a long background using structural steel.

Charles N. Pegelow gave his experienced, relevant opinion that the WTC buildings did not collapse due to plane impacts and fire, exclusively. He also doesnt put much stock in the pancake theory at all, saying that this would not apply to a welded, redundant steel structure, over-designed to withstand extreme environmental factors like a strong coastal storm.

You can listen to his debut interview at the RBN archive, for Thursday, August 24, 2006, in the 2nd hour (Hr2)
http://mp3.rbnlive.com/Fetzer06.html

You can view his resume here;
http://911blogger.com/node/2257
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greyl Donating Member (1000+ posts) Send PM | Profile | Ignore Fri Aug-25-06 07:26 AM
Response to Original message
1.  Is it this Charles N. Pegelow?
Pegelow: "My insurance company hired a very competent structural engineer ..."
www.thehomeinspector.com/Marketer/3Marketer2000/3MMM14.html
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Jazz2006 Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Aug-26-06 05:14 AM
Response to Reply #1
22. Yes, that appears to be the guy.
Sure doesn't sound like a structural engineer, does he?

Oh, and by the way, his resume indicates that he's a Halliburton company alumni.

I'm surprised that the "truthiness seekers" haven't called him out as a government shill yet.

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screembloodymurder Donating Member (1000+ posts) Send PM | Profile | Ignore Fri Aug-25-06 07:38 AM
Response to Original message
2. No advanced degree - is he a PE?
If not, he's no structural engineer. He can't even practice design w/o someone else stamping his work. The 911TM needs to do better.
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gbwarming Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Aug-26-06 01:22 AM
Response to Reply #2
15. PE Civil in the California database. Doesn't show a Structural authority
He might have Structual license in another state or I suppose he could be grandfathered in CA although I would have expected the board to have issued him a number in that case.

I didn't hear him make the claim that he ws a Structural Engineer, only Fetzer did that.
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AZCat Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Aug-26-06 01:42 AM
Response to Reply #15
16. He would have a license number even if he had reciprocity/grandfathering
I checked the Texas database and he wasn't listed (even for civil). It's possible that Fetzer doesn't understand the difference between civil and structural.
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greyl Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Aug-26-06 02:14 AM
Response to Reply #16
19. Fetzer didn't even know the towers were clad in aluminum. (!)
Edited on Sat Aug-26-06 02:16 AM by greyl
I was absolutely stunned at that admission. I mean, c'mon.

I listened to the mp3, and I didn't hear any structural engineering expertise from Pegelow.
It only sounded like he'd just watched a misleading movie like 9/11 Eyewitness.

Interestingly, he didn't argue against the pancake theory:

Pegelow: Once the thing starting initiating and it was progressing down, well you could say anything about I guess, uh... you know, once the velocity started taking it down at that point, but what I'm talking about is what actually initiated it.


Essentially, he makes the claim that he can't understand how the collapse began as a result of the plane impact, structural damage, and fires. He offers no calculations or specific knowledge, just a kind of hollow "it don't make sense to me", which is nothing knew among the CD hobbyist.

Another point missed, were the aluminum oxygen tanks from the plane. They latched onto the oxygen aspect, and forgot about the source of aluminum. In addition to the huge error with F vs C, did Fetzer admit it was possible that the glowing material flowing from the Tower was aluminum? Nope. He just can't imagine how that would be possible.

I was totally embarrassed for Fetzer when he was choking on his words at the beginning of the show.

Carefulplease is doing a good job with some of the details, I must say.

edit: spling
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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Fri Aug-25-06 03:59 PM
Response to Original message
3. Some problems with his arguments...
(I've just posted this in another thread)

You are right. One can no longer say that no structural engineer has ever challenged the impact+fire explanation of the collapse.

I've listened to the recent interview of Charles N. Pegelow by Jim Fetzer. He seems to base its assessment on the premises that (1) no perimeter column and no core column experienced a temperature exceeding 250 degree and 500-525 degree respectively. (Fetzer suggested that these were Fahrenheit figures, he concurred. I though this was a mere slip but he later reiterated that these were Fahrenheit figures he was talking about.)

He also assumes that (2) the whole structure is 9 times stronger than what is required to support the dead loads, in order for it to be able to resist the worst case wind loads.

He assumes that (3) the "reinforced concrete" floors would not fail because the slabs are under compression.

He claimed that the fires were not hot enough to (4) break the windows or (5) melt the aluminum claddings on the perimeter columns.

He concurs with Fetzer that (6) the towers were designed to withstand the impact of a Boeing 707.

His main argument is that because of the enormous reserve capacity of the towers, "some aircraft impacts" and "some fires" would not bring down the structure. This is not a compelling argument.

All the premises listed above are false or ungrounded.

(1) The NIST figures he cites are Centigrade, not Farenheit. They concern small, non representative physical samples of a fraction (1 to 3%) of the 287 column segments on the impact floors of WTC1 and WTC2.

(2) There is no ground for this figure. The numbers I've seen in the literature for the reserve capacity of cold columns are closer to ~500% for the perimeter columns and ~33% for the core columns, not an overall ~800%.

(3) The floors would still sag when the bottom cords or the supporting trusses expands. The top cord and the slabs resisting in compression is irrelevant.

(4) The windows were observed to brake as the fires progressed.

(5) The claddings weren't in contact with the steel. They were insulated from it. And a large temperature differential is expected between the inner and outer webs of the columns. This phenomenon in itself promotes buckling.

(6) The towers were not designed to withstand the impact of an aircraft travelling at cruise speed. The engineers considered the possibility of an impact from an aircraft lost in fog attempting to land on an approach course. There is a 6 to 10 fold difference in kinetic energy between the envisaged scenario and the 9/11 impacts.
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mhatrw Donating Member (1000+ posts) Send PM | Profile | Ignore Fri Aug-25-06 05:03 PM
Response to Reply #3
4. Please explain your use of the term "non representative."
Edited on Fri Aug-25-06 05:07 PM by mhatrw
On what do you base your contention that the WTC steel examined by NIST was "non representative"? "Non representative" of what? Is it your claim that NIST selectively examined recovered metal that it determined would be less likely to exhibit exposure to high temperatures?

I'm asking because my understanding is just the opposite -- that is, if the sample examined by NIST could be deemed "non representative" in any way it is because NIST selectively examined recovered pieces that they determined were localized in the vicinity of the highest fire temperatures.

Furthermore, even within this skewed sampling, NIST found nary a shred of hard, physical evidence that even a single piece of recovered WTC steel had ever been exposed to temperatures in excess of 600C.

The claddings weren't in contact with the steel. They were insulated from it. And a large temperature differential is expected between the inner and outer webs of the columns. This phenomenon in itself promotes buckling.

Yes, a large temperature differential is expected. But from the actual examination of the physical evidence, none was observed.
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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Fri Aug-25-06 05:40 PM
Response to Reply #4
5. Representativeness of the samples.
The steel samples examined by NIST are not representative of temperature distributions in the burning WTC Towers in 9/11 for many reasons.

(1) The selection criteria involved many factors besides possible fire exposure. Samples representative of typical failure modes or aircraft impact damage were also sought.

(2) When there was forensic evidence that the heat exposure or mechanical damage could have been incurred in the rubble pile the samples were discounted. This leaves very few unambiguous samples. Much of the steel of the impact floors was crushed and buried deep under the steel and material of many floors above (tens of thousands of tons) and was exposed to very hot underground fires for many weeks.

(3) The paint cracking method only worked when there was enough paint remaining to perform the analysis. This was seldom the case. Most often there was no paint remaining at all. This skewed the results since the column areas exposed to the most extreme temperatures and to aircraft debris impacts weren't likely to have had as much paint remaining on them as other samples had.

(4) The sample size is much too small for the results to be statistically significant.

This list is not intended to be exhaustive.
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mhatrw Donating Member (1000+ posts) Send PM | Profile | Ignore Fri Aug-25-06 07:25 PM
Response to Reply #5
7. Can you supply any evidence for any of your dubious claims?
(1) The selection criteria involved many factors besides possible fire exposure. Samples representative of typical failure modes or aircraft impact damage were also sought.

Are you contending that metal recovered from the direct impact zone would be less likely to exhibit heating than randomly selected metal? Sorry, but that makes no sense.

(2) When there was forensic evidence that the heat exposure or mechanical damage could have been incurred in the rubble pile the samples were discounted. This leaves very few unambiguous samples. Much of the steel of the impact floors was crushed and buried deep under the steel and material of many floors above (tens of thousands of tons) and was exposed to very hot underground fires for many weeks.

Do you have any evidence for this ridiculous claim? Yes, one of the three external panels that showed paint cracking demonstrated signs of being heated post-collapse. But rather than being systematically excluded from the survey, it was instead included with this fact explicitly noted. What evidence do you have that any other recovered samples showing significant post-collapse heating were treated any differently?

(3) The paint cracking method only worked when there was enough paint remaining to perform the analysis. This was seldom the case. Most often there was no paint remaining at all. This skewed the results since the column areas exposed to the most extreme temperatures and to aircraft debris impacts weren't likely to have had as much paint remaining on them as other samples had.

Again, I have to ask you exactly what evidence you can supply that supports this wild theory of yours. For example, what perimeter columns were examined that had "no paint remaining at all"? The answer, of course, is none whatsoever.

(4) The sample size is much too small for the results to be statistically significant.

Would you care to demonstrate this dubious contention of yours for us mathematically?
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BootinUp Donating Member (1000+ posts) Send PM | Profile | Ignore Fri Aug-25-06 07:54 PM
Response to Reply #7
9. His point about samples affected by the collapse and subsequent
fires in the pile is certainly not dubious. Its probably the single biggest problem they had in gathering your physical evidence for you.

Look in that older thread you referred us to and I posted in a short time ago, the OP has taken info about the sampling methods from the NIST report and included it in his post.
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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Sat Aug-26-06 03:25 AM
Response to Reply #7
20. "Mud cracking" method of max temperature evaluation.
Edited on Sat Aug-26-06 03:27 AM by Carefulplease
Edited to fix bold tags.

(3) The paint cracking method only worked when there was enough paint remaining to perform the analysis. This was seldom the case. Most often there was no paint remaining at all. This skewed the results since the column areas exposed to the most extreme temperatures and to aircraft debris impacts weren't likely to have had as much paint remaining on them as other samples had.

Again, I have to ask you exactly what evidence you can supply that supports this wild theory of yours. For example, what perimeter columns were examined that had "no paint remaining at all"? The answer, of course, is none whatsoever.


That is not a theory of mine and the claim isn't wild at all. I do not know how many (if any) full panels (columns-trees : 3 columns x 3 floors) had no paint remaining on them at all. Only panels with known as-built location were selected. Areas on those panels were selected for mud cracking analysis on the basis of the paint condition. They were selected "provided that sufficient paint was available for the analysis". Mechanical damage would also produce mud cracking. However this would result in directionality in the pattern. Such samples were "dismissed" (NISTAR1-3C p. 219.)

Four core columns were examined. Two of them had no sufficient paint available anywhere on them. The other two had "minimal" paint on "three to five spots per column". The cause of the loss of paint was not determined and could have been due to "pre- or post-collapse temperature excursion, ambient corrosion subsequent to collapse, or mechanical damage". (My emphasis)

http://wtc.nist.gov/NCSTAR1-3Cchaps.pdf
pp. 219-220
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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Sat Aug-26-06 03:59 AM
Response to Reply #7
21. Statistical significance...
(4) The sample size is much too small for the results to be statistically significant.

Would you care to demonstrate this dubious contention of yours for us mathematically?


For instance four (presumed) fire exposed columns were examined. None was shown to have been heated much above 600C (I'm simplifying). The sample is 4 and the population is 47 ((47*2)/2)

If half the fire exposed core columns had been heated to more than 600C and this were detectable -- and according to NIST fire dynamics model, fewer columns were actually so heated -- then the most probable result of the testing would be 2 positives and 2 negatives. The probability to get 4 negatives would be (1/2)^4 = 1/16. This is more probable than 1/20. Hence it is not statistically significant according to most measures (p < .05 or p < .01)

In the case of the "core columns heated above 250C" results, the statistical significance is even weaker. The case of the perimeter panels is closer to being significant but the results (~10% above 250C) are consistent with NIST's fire models.

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zforce Donating Member (157 posts) Send PM | Profile | Ignore Sat Aug-26-06 09:49 PM
Response to Reply #21
31. Umm...
Edited on Sat Aug-26-06 10:12 PM by zforce
Careful stated...

The case of the perimeter panels is closer to being significant but the results (~10% above 250C) are consistent with NIST's fire models.

Yet the fact of the matter is, the NIST actually doesn't have one perimeter column conclusively attesting to temps above 250c.

Furthermore, you neglect the fact that the NIST had omitted two investigative tools- Metastable Phases in Weld Metal and Relaxation of Residual Stresses in Welds. These two forensic tools would have determined in themselves the exact temps most of the steel had reached(between 300c and 500c), including steel lacking paint and the 3 pieces of steel with paint that MIGHT have exceeded temps of above 250c(mudcracking).

Also you should note the "discrepencies".

See Nist Appendix D

Comparing the results from the two analyses, some discrepancies exist where the visual observations made by WJE were in opposition to that of the results of the paint mapping technique utilized by NIST. As most of the observations of sooting and paint damage made by WJE were corroborated by the fire exposure-time sequence maps, it may be that a degradation mechanism exists where the primer paint exposed to the pre-collapse fires was damaged (resulting in the visual patterns) without increasing the local temperature of the steel above 250 C.

Z: The above statement is explaining the discrepency with regard to what the WJE had observed (soot and paint damage) and what the NIST had mapped..In other words, the NIST had mapped an area that the WJE had observed to be damaged, as an area where there shouldn't of been steel temps of above 250c. Hence the nist goes onto explain that maybe there is a "degrading mechanism" that can damage the paint faster and keep the steel temps from increasing above 250c.

From there, we move onto another discrepency, and in all actuality, quite opposite of the preceding one...

Additional to the discrepancy between the visual observations of WJE and the paint mapping technique of NIST, there were seven panels where precollapse fires were observable, yet neither analysis technique indicated the exposure on the recovered panel. One example of this was from piece M-2 where images show fires/external flaming for over 16 continuous minutes on the 98th floor (Sec. 2.3.1).


Fires for 16 minutes on 7 panels, yet no evidence of exposure over 250c?

In all reality, just one panel of steel from the fire area should/could be representative of all the steel in the Fire Area, since all the steel was primarily affected in the same way by the fires, that is to say..Fires for almost the same amount of time(give or take a few mins (16 to 20 minutes-dwell times).



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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Sun Aug-27-06 12:13 AM
Response to Reply #31
34. I am not so careful anymore...
Edited on Sun Aug-27-06 12:14 AM by Carefulplease
Careful stated...

The case of the perimeter panels is closer to being significant but the results (~10% above 250C) are consistent with NIST's fire models.


Yet the fact of the matter is, the NIST actually doesn't have one perimeter column conclusively attesting to temps above 250c.

Did I ever contest this "fact of the matter"? (Although they do have three samples "tentatively" attesting to such temperatures, if you will.) The issue here is the actual significance of this fact for our knowledge the condition of the WTC steel on the fire floors prior to the collapses in 9/11 2001.

Furthermore, you neglect the fact that the NIST had omitted two investigative tools- Metastable Phases in Weld Metal and Relaxation of Residual Stresses in Welds. These two forensic tools would have determined in themselves the exact temps most of the steel had reached(between 300c and 500c), including steel lacking paint and the 3 pieces of steel with paint that MIGHT have exceeded temps of above 250c(mudcracking).

I did not mentions the methods of Metastable Phases in Weld Metal and Relaxation of Residual Stresses in Welds? My, my... How could I've neglected that! I bow my head in shame.

However, the only mentions of these techniques I could find in relation with the 9/11 events were located in some of the NIST progress, draft and final reports.

(A)http://wtc.nist.gov/pubs/MediaUpdate%20_FINAL_ProgressReport051303.pdf
(B)http://wtc.nist.gov/NISTNCSTAR1-3.pdf
(C)http://wtc.nist.gov/NISTNCSTAR1-3Cchaps.pdf

Examinations of stable and metastable phases *were* performed. (B) p.95 and (C). They yielded many interesting results regarding the steel manufacturing process. The existence of many confounding factors and calibration issues limited their forensic uses.

The "stress relaxation" method is not further mentioned after (A). This might be because the calibration process was tricky, or it proved inapplicable to the available samples, or it put the NIST scientists asleep, or maybe it revealed the presence of thermite and so it was suppressed.

Also you should note the "discrepancies".

See Nist Appendix D

Comparing the results from the two analyses, some discrepancies exist where the visual observations made by WJE were in opposition to that of the results of the paint mapping technique utilized by NIST. As most of the observations of sooting and paint damage made by WJE were corroborated by the fire exposure-time sequence maps, it may be that a degradation mechanism exists where the primer paint exposed to the pre-collapse fires was damaged (resulting in the visual patterns) without increasing the local temperature of the steel above 250 C.

Z: The above statement is explaining the discrepency with regard to what the WJE had observed (soot and paint damage) and what the NIST had mapped..In other words, the NIST had mapped an area that the WJE had observed to be damaged, as an area where there shouldn't of been steel temps of above 250c. Hence the nist goes onto explain that maybe there is a "degrading mechanism" that can damage the paint faster and keep the steel temps from increasing above 250c.

This is a bit of a stetch. They just say that the damage observed by WJE could occur at temperatures below 250C. These are samples that NIST tested negative -- hence the discrepancy. The samples did not display the peculiar isotropic pattern of mud-cracking NIST found to be indicative of temperatures above 250C. So the discrepancy is of no consequence for NIST's (few) positive samples.

From there, we move onto another discrepency, and in all actuality, quite opposite of the preceding one...

Additional to the discrepancy between the visual observations of WJE and the paint mapping technique of NIST, there were seven panels where precollapse fires were observable, yet neither analysis technique indicated the exposure on the recovered panel. One example of this was from piece M-2 where images show fires/external flaming for over 16 continuous minutes on the 98th floor (Sec. 2.3.1).

Fires for 16 minutes on 7 panels, yet no evidence of exposure over 250c?

Duration of flame exposure is just one factor in columns heating. NIST's fire models and fire tests show this. Gas flows and radiation from other surfaces contribute much. External flaming can be accompanied with inflows through the window bases and cold currents on the interior walls.

In all reality, just one panel of steel from the fire area should/could be representative of all the steel in the Fire Area, since all the steel was primarily affected in the same way by the fires, that is to say..Fires for almost the same amount of time(give or take a few mins (16 to 20 minutes-dwell times).

No. The fire models and tests (and common sense) indicate that the fires affect the steel differently as a function of a great number of factors related to area geometry, the presence of partitions, proximal surface temperatures and irradiation, gas flows, oxygen availability, etc.
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Sun Aug-27-06 02:49 AM
Response to Reply #34
35. You have to be more precise..
with your statements.

What did you mean by the following statement?

The case of the perimeter panels is closer to being significant but the results (~10% above 250C) are consistent with NIST's fire models.

How about this..explain how the Negative results (temps less than 250c) are consistent with 10% of the steel being above 250c?

Are the following 7 pieces of steel calculated in your "10% above 250c" figure..

Additional to the discrepancy between the visual observations of WJE and the paint mapping technique of NIST, there were seven panels where precollapse fires were observable, yet neither analysis technique indicated the exposure on the recovered panel. One example of this was from piece M-2 where images show fires/external flaming for over 16 continuous minutes on the 98th floor (Sec. 2.3.1). ?

Careful goes on to say...

I did not mentions the methods of Metastable Phases in Weld Metal and Relaxation of Residual Stresses in Welds? My, my... How could I've neglected that! I bow my head in shame.

However, the only mentions of these techniques I could find in relation with the 9/11 events were located in some of the NIST progress, draft and final reports.


Thee following testing methods were never performed by the NIST when determining steel temperatures...

(NIST)

The examination of residual stresses and metastable phases in welds have yielded two possible

additional tests for detecting high temperature exposure. Measured stress profiles across

weldments show that the weld stress relaxes gradually upon heating to temperatures between

300 C and 600 C. Using calibration techniques, it would be possible to characterize

temperature exposure with an estimated 50 C accuracy. Regarding metastable phases,

irreversible phase transformations from an unidentified phase were seen at roughly 400 C in

differential scanning calorimetry studies of weld metal. If the phase can be identified as a

common one for ferrous weldments, this technique could act as a .litmus. test for this

temperature.

NIST NCSTAR 1-3C, WTC Investigation

Metastable Phases in Weld Metal

.....the technique would need to be calibrated on identical welds that were known not to have burned. Nevertheless, this technique remains available if needed to apply to critical temperature determinations on a specific component.(remains available 2005)

D.2.4 Relaxation of Residual Stresses in Welds

the technique would need to be calibrated on identical welds that were known not to have burned. Nevertheless, this technique remains available if needed to apply to critical temperature determinations on a specific component.



It is my personal belief that the Nist did carry out the tests above, and further that those results came back presenting LOW steel temps, just like the rest of the Sample.

And if that was the case(low steel temps including those 3 inconclusive samples), then that would in fact bring the whole NIST investigation/hypothesis to a complete stop, since it would remove the UNSUPPORTED assumptions that the FEW pieces of steel that found themselves in "no mans land" ( 251c to 600c) somehow supposedly supported the NIST case that steel reached critical temps of 550c etdc.., even though over 170 pieces hadn't.

That is the only reasonable explanation I can find for the NIST supposedly "not finishing its JOB" or in other words, determining the exact temp those 3 inconclusive pieces of steel via the forensic tools of residual stresses and metastable phases .









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AZCat Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Aug-27-06 06:48 AM
Response to Reply #35
36. Without any corroborating evidence...
I think your personal belief about the annealing in welds being calibrated and tested (and subsequently failing to indicate high temperature exposure) is insufficient to damn the NIST. You claim that this is the only reasonable explanation you can find for the NIST not further exploring this (at least in publications), yet don't seem to have put any energy into investigating why else (other than your dubious theory).
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Sun Aug-27-06 12:58 PM
Response to Reply #36
37. Go ahead AZ, explain why the NIST
Edited on Sun Aug-27-06 01:02 PM by zforce
chose not to perform such accurate forensic tests on the remaining samples of steel (steel that lacked paint, and on the 3 pieces of steel that MIGHT have experienced temps above 250c.

Surely you can explain why the NIST didn't think it worthwhile to have one piece of steel conclusively supporting their silly little hypothesis?
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AZCat Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Aug-27-06 01:49 PM
Response to Reply #37
38. Why don't you ask them, instead of asking me?
Rather than living in the land of "suppose" why don't you actually find out? And what evidence do you have that the test are really that accurate? We all know that annealing occurs, but does it respond linearly and consistently? If not it's going to be a bitch to model. Contacting the BFRL might be a nice idea also - they know lots about this stuff.
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Sun Aug-27-06 02:27 PM
Response to Reply #38
39. I already did ask them..
and they responded with basically a "You got me, I really don't know exactly why the tests weren't performed, maybe it had something to do with time and money constraints" (stephen banovic).

Further AZ states...Rather than living in the land of "suppose" why don't you actually find out?

Z: Maybe you should advise the NIST of this philosophy of yours.

And what evidence do you have that the test are really that accurate?

Z: Ummm..I thought I already did, surely the NIST statment I provided stating such tests are really that accurate can be taken as evidence, NO?

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seatnineb Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Aug-27-06 02:34 PM
Response to Reply #39
40. Welcome to DU Zforce !.....I like your style!
Edited on Sun Aug-27-06 02:35 PM by seatnineb
Keep up the great work!

:hi:
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Sun Aug-27-06 03:23 PM
Response to Reply #40
43. Thanks for the welcome and complement.
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AZCat Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Aug-27-06 02:42 PM
Response to Reply #39
41. I disagree.
You assume that calibration can actually occur between unheated welds and those exposed to heat - this all depends on the existence of a common phase. We don't have anything to show whether or not this is true.

Stephen Banovic's answer sounds legitimate to me - perhaps this was sacrificed in lieu of more important investigation? Did he provide names of those who would be able to clarify further?

It would be nice if the NIST had done this, but I understand that they might have limitations not readily apparent, just as you might have limitations on how much time and energy you might be able to devote to investigating the investigation.
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Sun Aug-27-06 03:22 PM
Response to Reply #41
42. Disagree all you want..
however, it doesn't change the fact that


Measured stress profiles across
weldments show that the weld stress relaxes gradually upon heating to temperatures between
300 C and 600 C. Using calibration techniques, it would be possible to characterize
temperature exposure with an estimated 50 C accuracy. Regarding metastable phases,
irreversible phase transformations from an unidentified phase were seen at roughly 400 C in
differential scanning calorimetry studies of weld metal. If the phase can be identified as a
common one for ferrous weldments, this technique could act as a .litmus. test for this
temperature.(NIST)


Further, time constraints and money constraints sound like an explanation, however there seems to be a couple of problems with such an explanation..One in particular, The NIST's ONGOING WTC 7 Investigation. For some reason or another this investigation doesn't seem to be constrained by time or money.

So the question is, why would the NIST feel constrained by time and money regarding the investigation into to WTC 1 and 2,yet feel no constraint with regard to WTC7?



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AZCat Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Aug-27-06 03:27 PM
Response to Reply #42
44. Thanks for your permission.
It's nice to be able to disagree whenever I want. :)

I want to draw attention to the IF in the para you included in your post. Perhaps the phase wasn't identified as a common one? Again - it would be nice to know if they did pursue this to that end, but I reiterate my point made several posts above - I think it is wrong for you to assume that the only reason the NIST didn't publish anything about this is because they wanted to hide conclusions that disagreed with their hypothesis.

The question about constraints, again, should not be directed to me. I wasn't in charge of either the budget or the schedule for the investigation.
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Sun Aug-27-06 04:00 PM
Response to Reply #44
45. Maybe you're having trouble understanding..
Edited on Sun Aug-27-06 04:00 PM by zforce
the NIST's official position that they never implemented the tests,thus they would have no idea if the phase was a common one or not.

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AZCat Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Aug-27-06 04:04 PM
Response to Reply #45
46. Ah - I did misunderstand.
That isn't uncommon (either for me or for the forum in general).

My other point still stands, though.
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Sun Aug-27-06 04:07 PM
Response to Reply #46
47. What point is that?
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AZCat Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Aug-27-06 04:10 PM
Response to Reply #47
48. The one about constraints.
I'm not in a position to answer that.
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Sun Aug-27-06 04:23 PM
Response to Reply #48
49. Indeed we both agree..
your following point stands

"I'm not in a position to answer that."









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AZCat Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Aug-27-06 04:27 PM
Response to Reply #49
50. It would be pointless for me to engage in supposition about this.
Did Stephen Banovic point you in the direction of anyone who might be in a position to answer your questions?
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Sun Aug-27-06 05:17 PM
Response to Reply #50
51. NO.
He couldn't give me an "answer" nor could he point me to an "answer", all he could do was "suppose", just like me(though my suppostion does make more sense).
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mhatrw Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Aug-28-06 04:26 PM
Response to Reply #36
71. It's highly ironic that you fault zforce for not providing
"corroborating evidence" for his rational deductions concerning NIST's physical survey (using the process of elimination) considering the fact that NIST's own assessment of its recovered metal offered no ""corroborating evidence" whatsoever for its assumptions regarding the towers' collapses.
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AZCat Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Aug-28-06 07:53 PM
Response to Reply #71
72. Why is that ironic?
Please explain why it is ironic for me to ask zforce for corroboration. Please be sure to note that I am not at present an employee of the NIST nor was I involved in the WTC collapse investigation so I am in no way responsible for the contents of any of their reports, including assumptions or conclusions within those reports. Zforce, on the other hand, is responsible for the assumptions and deductions he or she makes in his or her posts.
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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Sun Aug-27-06 05:35 PM
Response to Reply #35
52. NIST *did* attempt implementations of these methods...
Edited on Sun Aug-27-06 06:20 PM by Carefulplease
Edited: rephrased subject for clarity.

However they ran into calibration issues. You previous quotes were selective.

D.2.4 Relaxation of Residual Stresses in Welds

In addition to metastable microstructural phases, residual stresses develop during weld cooling. These form when the yield stress of the cooling metal increases sufficiently to resist deformation against the thermal expansion (contraction) stresses within the weld metal. If the weld metal cools fast enough, the stresses trapped within the structure are large. Annealing at a given temperature will allow the stresses to relax by lowering the flow stress of the metal and allowing plastic flow to occur. Measurement of the residual stresses in welds was surveyed as a possible indicator of the temperature that might have been reached in a fire.

Figure D6 shows the residual stress profiles measured in prototype welds on non-WTC steel using neutron diffraction. The technique is able to resolve the stresses sufficiently to be able to determine temperature exposures between 200 C and 500 C with an estimated resolution of 50 C. However, this technique suffers from the same difficulties as the DTA technique described above. The sample preparation was time-consuming and critical. Since the flow stress depends on chemical composition as much as the presence or absence of metastable phases, the technique would need to be calibrated on identical welds that were known not to have burned. Nevertheless, this technique remains available if needed to apply to critical temperature determinations on a specific component.


http://wtc.nist.gov/NISTNCSTAR1-3CAppxs.pdf
p. 436

You ought to read about the difficulties with the DTA technique (used for the detection of metastable phases) in the same document.

Regarding your other issues: You can not infer from the late arrival of the WTC7 final report that they have an unlimited budget.

And, yes, those 7 perimeter panels were taken into account in my 10% figure since NIST merely augmented to 21 panels the sample that had already been examined by WJE.
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Sun Aug-27-06 08:35 PM
Response to Reply #52
53. My, my..it seems you are misinterpreting once again,,
They did not implement the tests on said steel/welds. All they did was describe the "difficulties" in determining the "flow stress". Thus if they were going to implement the tests they would need to be calibrated on identical welds that were known not to have burned (removing the difficulties).

Hence...

"...this technique remains available if needed to apply to critical temperature determinations on a specific component.(NIST)


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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Sun Aug-27-06 09:58 PM
Response to Reply #53
55. I've read that quote already. You leave out the rest...
What immediately precedes this quote is precisely the answer to your question. You should have included it when you first asked you question. You also leave out the associated difficulties this method shares with the metastable phases analysis method:

DTA scans of weld metal would, thus, in the case of similar welds, predict exposure of the base metal to temperatures in excess of 400 C, and would be a litmus test for that temperature. Difficulties arise when trying to broadly apply this technique to the rest of the materials recovered by National Institute of Standards and Technology (NIST). Sample acquisition and preparation was time consuming, as was the actual experiment. Also, given the 14 different grades of steel and the many different welding techniques and materials used in the fabrication of the various components in the WTC, different chemistries, welding temperatures, and cooling rates will produce different metastable phases, each with a characteristic transformation temperature. Each weld would need to be examined in detail and calibrated with tests of identical material that was known not to have burned. These operational requirements make this technique very difficult to apply, but it was still available if a detailed examination of a critical element was necessary.

In addition, you asked: "Explain why the NIST chose not to perform such accurate forensic tests on the remaining samples of steel (steel that lacked paint, and on the 3 pieces of steel that MIGHT have experienced temps above 250c.

Surely you can explain why the NIST didn't think it worthwhile to have one piece of steel conclusively supporting their silly little hypothesis?"


NIST found evidence that one of these three piece (K-16) was heated in the debris pile. Such tests would have been of little use. Another one (K-1) does not show heating in a weld area. These testing methods only apply to welds. The remaining piece (K-2) gave indication of heating below the truss seat. NIST *did* perform other microstructural examinations and hardness measurements. They concluded that the sample did not experience temperatures above 500C. I suppose this was good enough for them. The steel wouldn't have weakened significantly at temperatures above 400C yet below 500C.



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zforce Donating Member (157 posts) Send PM | Profile | Ignore Sun Aug-27-06 11:07 PM
Response to Reply #55
57. What's going on here?
Edited on Sun Aug-27-06 11:44 PM by zforce
(corrected for change in the subject-line)

I thought the issue between you and I was "Did the NIST implement these tests or didn't they".

You said they *did*, I said they *didn't* and proved it in my last post , however for some reason or another you ignored this issue with your last post, and in fact seemed to shift your position from...



"NIST *did* implement these methods (changed)

to

'NIST *did* perform other microstructural examinations and hardness measurements.

Can you clarify your position for me, did they or didn't they implement the tests in question?
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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Sun Aug-27-06 11:57 PM
Response to Reply #57
60. they did *attempt* to implement the method.
You are misquoting me. Notice the word "attempt" in my subject line (edited long before your reply). Actually they used the first method on welds that had known properties. They discovered that they couldn't use it "broadly" on the collected samples because of the severity of the callibration issues.
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Mon Aug-28-06 12:03 AM
Response to Reply #60
61. What was you subject line before you editted it?
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Mon Aug-28-06 11:37 PM
Response to Reply #55
75. Getting back to where we had left off..
Edited on Tue Aug-29-06 12:30 AM by zforce
You state..

NIST found evidence that one of these three piece (K-16) was heated in the debris pile. Such tests would have been of little use. Another one (K-1) does not show heating in a weld area. These testing methods only apply to welds. The remaining piece (K-2) gave indication of heating below the truss seat. NIST *did* perform other microstructural examinations and hardness measurements. They concluded that the sample did not experience temperatures above 500C. I suppose this was good enough for them. The steel wouldn't have weakened significantly at temperatures above 400C yet below 500C

Z: K-16 is basically irrelevant to our discussion, seeing that that is the column probably emanating from WTC 7(sulfidization).(my mistake for not pointing that out earlier)

However..

K-1 did indeed "show heating" in weld areas, specifically the flange area.

K-2 no implemetation or attempt to implement said tests (Metastable Phases in Weld Metal and examination of residual stresses) on said steel/weld.

Thus my point stands, the NIST chose not to exclude nor attempt to exclude many pieces of steel(including the above two)from temperatures between 300c to 600c for some odd reason. Yes, the tests were more difficult than examining the paint for mudcracking, but the fact remains..

"...this technique remains available if needed to apply to critical temperature determinations on a specific component.(NIST)"


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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Tue Aug-29-06 12:44 AM
Response to Reply #75
76. K-16 is from WTC1 or WTC2
K-16 is from WTC1 or WTC2. However it was from floor 53 or below. So we both are right that it is irrelevant to the present issue. (However it is relevant to Jones's thermate hypothesis. This was discussed in another thread recently.)

So, the technique might have been applied to K-1 and K-2. In view of the difficulties involved with the calibration it does not seem unreasonable to me that they did not apply them in addition to the other detailed examinations they performed.

You seem to overestimate the stakes in performing them. These two methods might be slightly more precise but maybe not more reliable than the paint mud-cracking method and other microstructural tests they performed. They might not have been able to obtain calibrating samples that would have been known to be relevantly similar with a sufficient degree of certainty.

The direct fire exposure to the perimeter columns was found to be much less critical in the collapse initiation sequence than were the sagings of the truss floors and the plastic creep of the core columns. The loss of lateral bracing on the perimeter walls on the height of many floors was the primary cause of their initial buckling failure.
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dailykoff Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Aug-29-06 02:52 PM
Response to Reply #76
83. HA! You just bought the farm.
The direct fire exposure to the perimeter columns was found to be much less critical in the collapse initiation sequence

Right you are.

than were the sagings of the truss floors and the plastic creep of the core columns. The loss of lateral bracing on the perimeter walls on the height of many floors was the primary cause of their initial buckling failure.

Total nonsense. The perimeter walls did not require the floor trusses either to support themselves (they supported the floor trusses) or to remain rigid. In addition to the spandrel plates and the joist girders in each floor (which the NIST "overlooks") the hat trusses and beam-framed floors, of which there were nearly a dozen in each tower, performed that function. In any case, loss of lateral bracing, if critical, would have produced bowing, not buckling.

Congratulations, you just admitted that the entire NIST collapse theory is horseshit.

:rofl:
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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Tue Aug-29-06 09:20 PM
Response to Reply #83
84. Not quite accurate...
(1) The perimeter walls supported the vertical loads of the truss floors while the trusses were *also* bracing the walls against vertical deflections.

(2) There were no joist girders in the truss framed floors. Some floors were beamed framed or some combination (some elevator floors were beam framed in the short span zones). The impacted and burning floors mostly were truss framed.

(3) The spandrel plates and the hat truss would not have helped much with bowing. Quite the contrary, the hat truss would have redistributed some of the load of the creeping core to the walls.

(4) Pronounced bowing would eventually leads to buckling and/or failure or splice plate connections.

(5) The pronounced bowing isn't an hypothesis; it is an observed datum.
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dailykoff Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-30-06 12:41 AM
Response to Reply #84
90. LOL, your story changes with every
dumbass post, just like debunking911's used to. Gee, where'd he go?

Anyway:

(1) The perimeter walls supported the vertical loads of the truss floors

--Bingo.


while the trusses were *also* bracing the walls against vertical deflections.

-- Obviously, but their loss would have no effect except maybe in a hurricane, as the perimeter walls were also braced by the structural elements I mentioned above.

(2) There were no joist girders in the truss framed floors.

--Wrong. The NIST report simply doesn't mention them. How the hell do you think the corners were supported?

Some floors were beamed framed or some combination (some elevator floors were beam framed in the short span zones). The impacted and burning floors mostly were truss framed.

--You're thinking of the escalator floors, not elevator floors, and I don't think that last statement is accurate.

(3) The spandrel plates and the hat truss would not have helped much with bowing. Quite the contrary, the hat truss would have redistributed some of the load of the creeping core to the walls.

--Just the opposite. The hat trusses would have redistributed loads away from the damaged columns.

(4) Pronounced bowing would eventually leads to buckling and/or failure or splice plate connections.

--So you're admitting there was no observed buckling, but there "would" have been. Okay.

(5) The pronounced bowing isn't an hypothesis; it is an observed datum.

--Any perimeter column bowing was a result of the top sections beginning to rotate. The certainly didn't cause it, except in the fantasy world of the 9/11 faithful.
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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Sat Sep-02-06 01:51 AM
Response to Reply #90
99. Some issues about the demise of the WTC Towers
while the trusses were *also* bracing the walls against vertical deflections.

-- Obviously, but their loss would have no effect except maybe in a hurricane, as the perimeter walls were also braced by the structural elements I mentioned above.

(2) There were no joist girders in the truss framed floors.

--Wrong. The NIST report simply doesn't mention them. How the hell do you think the corners were supported?


The corners of the two-way floor assemblies were supported by the corner core columns. We've already been over the issues of these joist girders. You seem to be the only person on Earth to know them to have ever existed. Have you found some new evidence?

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=125&topic_id=56836&mesg_id=99797

Some floors were beamed framed or some combination (some elevator floors were beam framed in the short span zones). The impacted and burning floors mostly were truss framed.

--You're thinking of the escalator floors, not elevator floors, and I don't think that last statement is accurate.


I am thinking of transit elevator floors such as the lobbies. The floors in the impact area of both towers all were truss framed. See the thread referenced above for references.

(3) The spandrel plates and the hat truss would not have helped much with bowing. Quite the contrary, the hat truss would have redistributed some of the load of the creeping core to the walls.

--Just the opposite. The hat trusses would have redistributed loads away from the damaged columns.


It works both ways -- whatever subsystem buckles or creeps transfers some load to the other until both are oveverloaded.

(4) Pronounced bowing would eventually leads to buckling and/or failure or splice plate connections.

--So you're admitting there was no observed buckling, but there "would" have been. Okay.


Bowing and loss of lateral support would have lead to one or the other (plastic buckling or splice failure.) I would assume that significant lateral deflection would soon lead to column failure. This is something all structural engineers who have studied the WTC demise seem to agree on.

(5) The pronounced bowing isn't an hypothesis; it is an observed datum.

--Any perimeter column bowing was a result of the top sections beginning to rotate. The certainly didn't cause it, except in the fantasy world of the 9/11 faithful.


This makes no sense. The bowing was observed half an hour before the collapse initiation. The top section began to rotate when a perimeter wall buckled past its yield point.

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dailykoff Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Sep-02-06 02:09 AM
Response to Reply #99
101. Thanks, your spelling is much improved.
Other than that, you haven't added anything to any of these issues except to rephrase your previous misunderstandings and mistatements and pad them out with a little fresh nonsense.

So please see my comments above and here:

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=125&topic_id=56836&mesg_id=99800

:)
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dailykoff Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Sep-02-06 10:16 AM
Response to Reply #101
104. p.s. the NIST apparently inhabits
an alternative engineering universe where basic terms and concepts like load transfer, redundancy, column buckling, and joist girders are unknown and a whole new Hollywood discourse is invented to describe never-before-seen 9/11 phenomena.

Weird. :shrug:
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Wed Aug-30-06 12:04 AM
Response to Reply #76
87. Detailed examinations?
So, the technique might have been applied to K-1 and K-2. In view of the difficulties involved with the calibration it does not seem unreasonable to me that they did not apply them in addition to the other detailed examinations they performed.


Let me explain something, these so called detailed examinations detailed nothing, as is attested by the fact that the NIST *doesn't* have one conclusive piece of evidence suggesting steel temps reached above 250c, let alone their target number 550c and higher.

What these detailed examinations left us with though, were a whole bunch of "dismissed" columns including another two core columns that lacked paint(making 4 all together 2paint+2no paint), and further, they left us with two pieces of steel(k-1 and k-2) with visible signs of mudcracking which could have or could not have been caused by the fire. IF caused by the fires as most Oct'ers WILL *assume*, then, to them its "evidence" that the fires were able to effect the steel.

Therefore, by the NIST CHOOSING *not* to perform such precise tests, they went ahead and bolstered their dying hypothesis in the eyes of their "FAITHFUL", by one, reducing the amount of steel tested thus being able to claim to their faithful, "Steel sample not representative", and by two, not eliminating columns k-1 and k-2, thus giving their faithful something to hold on to and use against those "wackos":-

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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Wed Aug-30-06 12:40 AM
Response to Reply #87
89. "NIST CHOOSING *not* to perform such precise tests"
We've been over this already. You inquired why NIST choose not to perform those two tests. There were quite severe calibrations issues.

They did not need to perform those particular tests to bolster their "dying hypothesis".

This "hypothesis" is merely that the law of physics held good on 9/11 2001. There were compelling reasons to believe that the insulation material was widely dislodged. Their model is very conservative in this respect. The fires were observed to be widespread and known to be hot. The physics of fire dynamics and heat transfer is well understood. They tested and calibrated their models with large scale burn tests. It would just have defied the laws of physics if the exposed columns had not heated to critical temperatures in such circumstances and in that timeframe.

This "hypothesis" was the consensus among expects before NIST even began their enquiry into the precise collapse initiations sequence. The "hypothesis" you refer to was so qualified, even, only by some amateur controlled-demolitionists with no relevant engineering qualifications.



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zforce Donating Member (157 posts) Send PM | Profile | Ignore Wed Aug-30-06 11:26 PM
Response to Reply #89
93. Enough already with the rationalizations...
"...this technique remains available if needed to apply to critical temperature determinations on a specific component."(NIST)


When all is said and done, it comes down to the fact the NIST didn't even TRY to apply these tests on the two specific components(k-1 and k-2) that were in need of critical temperature determinations, let alone the many other components that were just "dismissed" out of hand because they had lacked paint.

While your at it.. enough already with the suppositions regarding the the limited diffused fires.





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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Thu Aug-31-06 01:20 AM
Response to Reply #93
96. The fires weren't limited and diffused...
They were widespread and intense. The entry hole of the aircrafts and the several hundreds of blown out widow panes let much fresh oxygen in to vent the fires. The heat output was estimated to be in the order of 1 GigaWatt. That's the power of a typical nuclear power plant. The heat sink provided by the steel structure is also limited to the extent of the area where fire insulation (foam or wallboard) was dislodged.

The "availability" of your two beloved forensic tools for the examination of specific components does not entail the practicality, reliability or feasibility of their use in testing the two panel samples that had positive mud-cracking . If you still worry about that you might want to ask them how feasible it would have been to use them on the two items we discussed. They stated already why their widespread use is impractical.

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zforce Donating Member (157 posts) Send PM | Profile | Ignore Sun Aug-27-06 08:43 PM
Response to Reply #52
54. I don't understand..
You say...

"And, yes, those 7 perimeter panels were taken into account in my 10% figure since NIST merely augmented to 21 panels the sample that had already been examined by WJE."

Are you saying that NIST had a higher hypothetical percentage number of steel above 250c, but when said seven panels proved inconsistent they just lowered their hypothetical percentage number to 10%?

Please explain..
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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Sun Aug-27-06 11:00 PM
Response to Reply #54
56. That is not what I am saying...
What I am saying is that NIST examined sample areas from 21 fire-exposed perimeter panels. They found evidence of *pre-collapse* temperature in excess of 250C on two of them (not three). Thus my ~10% figure. You ask me if my figure takes into account the 8 panels previously examined by WJE. My answer is positive since these are panels K-2, N-8, N-7, N-12, S-9, S-10, C-11, M-14 (from the last appendix).

See http://wtc.nist.gov/NISTNCSTAR1-3Cchaps.pdf
p.208 and figure 2-48 for details on fire exposure and identification.

The 8 panels examined by WJE (including M-2) were all included in NIST's sample of 21. They are not 8 further panels.
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Sun Aug-27-06 11:19 PM
Response to Reply #56
58. You seem to be misunderstanding me
I am asking you if the NIST's Hypothetical position of 10% of the steel being above 250c had changed when they found CONCRETE EVIDENCE that some of that 10% percent they initially supposed was over 250c turned out to be less than 250c?

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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Mon Aug-28-06 12:04 AM
Response to Reply #58
62. There is no such hypothetical.
The ~10% couldn't have changed since it is *my* figure and I base it on their final conclusions. (2 positive results in 21 panels)

I've also argued that is has little statistical significance or representativeness.

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zforce Donating Member (157 posts) Send PM | Profile | Ignore Mon Aug-28-06 12:20 AM
Response to Reply #62
63. What the heck..
I had asked you to clarify your position in message #35.

Thus your 10 percent figure is nothing but wishful thinking, for there wasn't one piece of steel conclusively attesting to temps of above 250c..thus out of the 21 panels you have 0% attesting conclusively to temps above 250c.
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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Mon Aug-28-06 12:34 AM
Response to Reply #63
65. Did I ever even suggest that the positives were "conclusive"?
They provide good evidence of heating above 250C, that's all.
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Mon Aug-28-06 01:03 AM
Response to Reply #65
68. Yes,, you kinda did
You stated..

The case of the perimeter panels is closer to being significant but the results (~10% above 250C) are consistent with NIST's fire models.

Results = 10% above 250c

conclusion (kn-klzhn)
n.
1. The close or last part; the end or finish.
2. The result or outcome of an act or process.
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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Mon Aug-28-06 01:31 AM
Response to Reply #68
69. Not at all !
The two individual positive results being conclusive wouldn't improve at all the consistency of the testing results with the simulation results. Quite the contrary, their being inconclusive (or even useless) would lead to even better (or perfect) consistency with the simulation results whatever these would have been.

So, my claim of consistency can not be construed as an evidence that I took the results to be conclusive of (pre-collapse) temperatures higher than 250C in those panels.

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zforce Donating Member (157 posts) Send PM | Profile | Ignore Mon Aug-28-06 09:54 PM
Response to Reply #69
73. Lets slow down a bit..
Can you tell me how the tentative "results (~10% above 250C)" are consistent with the NIST's fire model?
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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Tue Aug-29-06 01:46 AM
Response to Reply #73
77. You will find the temperature histories in the relevant reports...
Check these and the relevant sub-reports.

http://wtc.nist.gov/oct05NCSTAR1-5index.htm
http://wtc.nist.gov/oct05NCSTAR1-6index.htm

The first one allows you to locate the fires. The second allows you to pinpoint the areas where insulation was damaged and what the temperature histories were.

Note that critical temperatures weren't reached in structural elements that had intact insulation. NIST assumed in their models that insulation was dislodged only in the direct path of the aircraft debris field. This is just a fraction of the areas where the fires spread. Those single columns that reached high temperatures also did not reach them uniformly and so could have tested negative when they could be tested at all. Overall this seems consistent with a satistically non-significant result of two positives in a sample of 21.

(When a columns heated as a consequence of insulation removal from aircraft debris, then it was also likely to miss primer paint to provide visual evidence of such.)

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zforce Donating Member (157 posts) Send PM | Profile | Ignore Tue Aug-29-06 10:22 PM
Response to Reply #77
85. I seem to be missing the part...
Edited on Tue Aug-29-06 10:22 PM by zforce
where the NIST states their fire model is consistent with the TENTATIVE results.

In fact, the NIST's fire model seems to be suggesting that there was a much higher percentage of columns being above 250c (emanating from the fire affected floors) , also their fire model results don't seem that tenetative.

Anyways...

A quick question..

How long(minutes) do you think it would take for a bare column to reach critical temps when exposed to a temperature of 1100c?



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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Tue Aug-29-06 11:16 PM
Response to Reply #85
86. Can you make your question more precise?
Radiation rather than conduction is the primary mode of heat transfer. So I would need to how deep the mass of heated gaz is. Is 1100C the top layer temperature and does it fall linearly to ~200C on the floor? Also, am I to assume that the column reaches 600C (or 650C?) uniformly, at the surface of the inner web or across the full thickness of the inner web plate? (Is that rather a core column? Is it a box or wide-flange beam?

What kind of simplifying assumption can you grant me? I am not sure I have the competence to perform the calculation but maybe I can try. I've never studied the theory of radiative transfer. However there are a couple engineers here (AZCat and LARED) who maybe will help.

As for NIST and their "tentative" results (tentative was my word, not their):

They've stated -- and I've argued -- that the samples are not necessarily representative of the other fire affected columns nor are the results statistically significant. For these reasons they do not contradict (hence are consistent with) the simulations.

I don't see that there was a much higher percentage (>10%) of columns that were heated above 250C, unless you only consider the fire exposed walls where insulation was damaged. This also motivates my claim of consistency.
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Wed Aug-30-06 12:18 AM
Response to Reply #86
88. A core column to reach temps of 550c.
They've stated -- and I've argued -- that the samples are not necessarily representative of the other fire affected columns nor are the results statistically significant. For these reasons they do not contradict (hence are consistent with) the simulations.

Z: Hmmm..I wonder what caused you to say that?
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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Wed Aug-30-06 12:45 AM
Response to Reply #88
91. What caused me to say that?
I have argued all of these points in some details already. If you are still unconvinced but have no new objections to my previous arguments, what do you expect me to add?

Let's agree to disagree is all I could say.
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Wed Aug-30-06 11:32 PM
Response to Reply #91
94. (cough)
87. Detailed examinations?


Therefore, by the NIST CHOOSING *not* to perform such precise tests, they went ahead and bolstered their dying hypothesis in the eyes of their "FAITHFUL", by one, reducing the amount of steel tested thus being able to claim to their faithful, "Steel sample not representative", and by two, not eliminating columns k-1 and k-2, thus giving their faithful something to hold on to and use against those "wackos..


Compare my statement with your "rationalization".

Careful stated...
They've stated -- and I've argued -- that the samples are not necessarily representative of the other fire affected columns nor are the results statistically significant. For these reasons they do not contradict (hence are consistent with) the simulations.
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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Thu Aug-31-06 12:44 AM
Response to Reply #94
95. I've compared the two statements...
Edited on Thu Aug-31-06 01:33 AM by Carefulplease
Edit -- reworking of first sentence.

Your statement consists in some ungrounded speculations as to the motives of the NIST investigators for choosing to perform some battery of exotic forensic tests to the exclusion of others -- and your trying to extract a smoking gun out of this.

My "rationalization" is just the reiteration of an earlier statement that you questioned and that I then backed up with arguments and calculation.

A statement that is true can not be a rationalization. Is it false? Why?
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Fri Sep-01-06 10:42 PM
Response to Reply #95
97. "Exotic forensic tests"?
Careful states..

Your statement consists in some ungrounded speculations as to the motives of the NIST investigators for choosing to perform some battery of exotic forensic tests to the exclusion of others -- and your trying to extract a smoking gun out of this.


Please point us to what has led you to claim the forensic tests were "exotic"?


In the meantime, let me state for the record, "the tests were not exotic", they might have been difficult( a little more work) as the NIST claims, but they were not exotic..In fact, they seem to be very common tests..

http://www.google.com/search?hl=en&lr=&q=Relaxation+of+Residual+Stresses+in+Welds+temperature

Results 1 - 10 of about 79,100 for Relaxation of Residual Stresses in Welds temperature.



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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Sat Sep-02-06 12:20 AM
Response to Reply #97
98. Relaxation of Persistent Pressures in Beans and the Production of Gases.
Edited on Sat Sep-02-06 12:22 AM by Carefulplease
Edited to fix tags

I would think these are exotic techniques. NIST seems to have merely surveyed them as potential tools. There is little evidence that those are standard tools in forensic fire investigations.

Consider that Google will return lots of irrelevent hits if you omit to put a phrase in quotation marks:

Relaxation of Residual Stresses in Welds temperature : 79,100 hits
Relaxation of Persistent Pressure in Beans gases: 108,000 hits
Observation of Persistent Anxieties in Dogs weather : 168,100 hits


However :

"Metastable Phase in Weld Metals" temperature : Zero hits
"Metastable Phase in Weld" temperature : Zero hits


The following more relaxed search works better:

"Relaxation of Residual Stresses" temperature : 1,100 hits

However, how relevant are those hits?

"Fire investigation" : 997,000 hits
"Fire investigation" "Presence of Accelerant" : 89 hits
"Fire investigation" "Matastable Phase" : 1 hit
(not a relevant hit)

Finally,

"Fire investigation" "Residual Stresses" : 42 hits

However these don't seem relevant either. If I further focus this search with the addition of such strings as "maximum temperature", "maximal temperature", "highest temperature" or "temperature reached", the only relevant hits I get (I got one irrelevant one) are links to the NIST investigation.







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zforce Donating Member (157 posts) Send PM | Profile | Ignore Sat Sep-02-06 02:01 AM
Response to Reply #98
100. Oh boy..
Edited on Sat Sep-02-06 02:05 AM by zforce
First you had failed to provide me with evidence for your claim that the NIST fire model is consistent with your belief that 10% of the steel sample was above 250c, now you fail to provide me with the evidence to support you claim that determining of residual stresses and metastables phases in welds are as you say, "Exotic".


The fact of the matter is, when it comes to determining if steel/welds have been exposed to elevated temps, metastable phases and residual stresses would bascially be Metallography 101.

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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Sat Sep-02-06 02:48 AM
Response to Reply #100
102. Theroretically possible -- yes. But are they practical?
The issue is whether these techniques are practical enough to be applied in forensic fire investigations without an excessive investment of resources. All you can provide about their use is 91,000 irrelevant Google hits (that mostly do not even relate to these techniques at all -- let alone as they relate to the determination of maximal temperatures). Could it be that there are zero relevant hits because the techniques are seldom used in the context of forensic engineering because of the severe calibrations issues NIST enumerates?

I did provide evidence that the results from the fire models are *consistent* with the analysis of the steel samples. Do you not agree that the results of the simulations show a proportion of the fire exposed perimeter panels that have been heated above 250C not to be very much higher than 10% -- so that obtaining a sampling of 2 in 21 isn't less probable that p = 0.05? Do not get mislead by the pictures of the fire exposed walls where the insulation was damaged that are shown in one of the NIST sub-report. That is just one fraction of the fire exposed walls.
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Sat Sep-02-06 03:55 AM
Response to Reply #102
103. No luck with "Exotic", eh?
Anyways, yes, for a METALLOGRAPHIC ANALYSIS that consists in determining the ***THERMAL EXCURSIONS*** experienced by the WTC steel such tests would indeed be very practical.

Now, with regard to the Google hits, rather than reading the number of specific keyword links, why don't you click on on one of the many links which will inform you of the SIMPLE calibration techniques.

http://www.davidson.com.au/products/strain/mg/technology/technotes/tn503.pdf#search=%

BTW, regarding your fire model...were the results of project 3/Task 5 (determining thermal excursions in steel) provided to the "fire modelers" before or after their fire model was complete?







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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Sat Sep-02-06 09:02 PM
Response to Reply #103
105. Some simple calibration technique...
The issue about calibration is not related to a difficulty in measuring accurately the stresses. It is rather related to the problem of mapping stress patterns to maximal temperature exposure in samples that have not been prepared in controlled conditions. What NIST needs is identical welds produced with identical techniques and with identical materials that are known not to have burned.

The reference you now present has no relevance to such calibration issues at all. It does not have any relevance to the issue of the determination of maximal reached temperature. It is just about one particular technique for measuring residual stresses in metals.

Now, for your second concern: The fire modeling team might have hoped for useful data from the metallurgical team at some point. I do not know. However, I do not suppose they would have put restrictions on the parameters of the model based on results that are not statistically significant.

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zforce Donating Member (157 posts) Send PM | Profile | Ignore Sat Sep-02-06 09:41 PM
Response to Reply #105
106. How "exotic" would that be..
...finding an identical piece of steel with the same weld(same manufacturer), but not burned?

Well, based on the hundreds of unburned samples I would suspect, not very.

Again, there is nothing exotic about the tests, they are simple tests that would be used to determine the thermal excursions that had taken place in the steel.

Example..

Burned piece
unburned piece(by george we found one)

Analysis of burned piece..note structure/stress
Analysis of unburned piece note structure/stress and then heat until structure matches the burned piece and then note temperature of match.

WOW..that was so exotic..

Now, for your second concern: The fire modeling team might have hoped for useful data from the metallurgical team at some point. I do not know. However, I do not suppose they would have put restrictions on the parameters of the model based on results that are not statistically significant.


Actually the fire modelers did indeed incorporate/tweak their model around the facts(steel less than 250c) and then created their own ("above 250c facts).


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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Sat Sep-02-06 10:13 PM
Response to Reply #106
107. It seems to me you might be underestimating the difficulties...
It still seems to me you might be underestimating the difficulties involved and the potential benefits. I have made my points and you have made yours. So, let us agree to disagree.
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Sat Sep-02-06 10:41 PM
Response to Reply #107
108. I highly doubt it..
Anyways, the fact remains, *NIST did not even attempt to perform* the tests on the many members that needed critical temperature determinations, which is in direct contradiction to their statement..

"...this technique remains available if needed to apply to critical temperature determinations on a specific component."(NIST)

No Careful, the quote in no way implies ..."this exotic test is not available for critical temperature determinations on specific components".



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AZCat Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-30-06 06:02 AM
Response to Reply #86
92. Man, I haven't done a PDE in forever.
We generally "cheat" whenever doing heat transfer analysis and use a linearized model (like RTS)because heat transfer as PDE (partial differential equation) can be a real pain in the ass. There are some computational tools that simplify the process some but I haven't used any of them.

Radiative heat transfer by itself isn't that complicated. It depends on the difference between the fourth powers of the absolute temperatures of the various surfaces, whereas conduction and convection just depend on the difference between temperatures (absolute or relative - it doesn't make a difference). This means that a model incorporating radiation is more sensitive to small differences between the model temperatures and actual temperatures and to differences in boundary conditions and therefore is less reliable when extrapolating.
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Sun Aug-27-06 11:28 PM
Response to Reply #52
59. Did you change the subject line from

(basically)
NIST implemented the tests

To

NIST ATTEMPTED to implement the tests
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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Mon Aug-28-06 12:27 AM
Response to Reply #59
64. It might have been interpreted thus.
I can't remember the original ambiguous phrasing but I tried to make my thought clearer. I apologize for my accusation of your misquoting me if this results from my edit. Did you read my original message long before you replied to it? It makes sense that you could have.

The remark on the further tests they made is not a diversionary tactic. The issue for me always had been why the tests weren't (broadly) implemented. I did not take your charge that they had been implemented and the results were suppressed seriously. I did not attempt to refute this. So the issue for me never has been "whether or not" but rather "why not".
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Mon Aug-28-06 12:58 AM
Response to Reply #64
66. That is what had happened.
I was replying to your original message, at which time I had gotten a little busy here at the house causing me to leave the partially typed message(reply) that I was typing and finish it at a later time.

Anyways..I'll respond to your clarified position sometime tomorrow.

Peace
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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Mon Aug-28-06 01:01 AM
Response to Reply #66
67. In that case I apologize again for the misunderstanding. n/t
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mhatrw Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Aug-28-06 04:17 PM
Response to Reply #21
70. How about the fact that NO recovered WTC metal whatsoever
showed any signed of being heated past 600C either pre- or post-collapse?

How can you and NIST simply dismiss this fact as statistically insignificant without invoking a shred of mathematical analysis, lot compliance sampling standards be damned?

NIST's model presume such conditions must have existed, yet not a single piece of NIST's recovered evidence suggests this fundamental assumption and only 2 pieces in total suggest even temperatures higher than 250C.

I can't think of single other speculative scientific hypothesis that could survived this complete lack of support in terms of the only directly measurable physical evidence.
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greyl Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Aug-28-06 10:16 PM
Response to Reply #70
74. We know the temperature of Uranus.
(Can you guess where I'm going with this?)

We know the temperature that jet fuel burns.
We know the temperature that various office furniture burns.
We have video evidence of apparently molten metal dripping from 1 of the towers that was clearly hotter than the softening point of steel. (There was more than one steel alloy used in the Tower's construction).
We have evidence of molten metal in the debris.

Why are CTists the only ones allowed to use that evidence to support their hypotheses?
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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Tue Aug-29-06 01:54 AM
Response to Reply #74
78. Those are good points...
In another forum NEW-FONZE remarked:

But on the topic of Herr Doktor Jones, here is a quote from "Why Indeed...":

Using metallographic analysis , NIST determined that there was no evidence that any samples had reached temperatures above 600 C.

Jones thinks this is a very important observation by NIST and uses it to argue that the steel columns did not get hot enough to soften and lose strength.

However, in the same "Why Indeed.." report Jones argues (i) That the temperature of hot spots in the rubble pile were approx 845 -1040C, and (ii) That the thermite he proposes was used to cut steel, created molten iron at very high temperatures initially above 2000C.

So, here we see Jones literally blowing hot and cold!
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mhatrw Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Aug-29-06 01:00 PM
Response to Reply #74
79. We think we know the temperature of Uranus.
If we sent a couple hundred probes to the surface of Uranus and they all told us that our estimate was off by several hundred degrees, what do you think would happen to our estimate?
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greyl Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Aug-29-06 01:09 PM
Response to Reply #79
80. Oh man, that was just a catchy subject line. :) However,
Edited on Tue Aug-29-06 01:17 PM by greyl
you would obviously be surprised how close our estimates of all manner of detail of heavenly bodies can be. It may be interesting for you to check out the science behind how we know.
Furthermore, Uranus isn't one temperature, but we have a damn good idea of the various temperatures at various depths of atmosphere at different points around the orb, and while it's at different points of it's movement.

Anyway, I think my point was made afte the subject line.
Any comment on the rest of my post?

edit: clarity
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mhatrw Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Aug-29-06 01:31 PM
Response to Reply #80
81. When direct evidence contradicts indirect evidence,
direct evidence wins.

If I stick 200 calibrated thermometers in Uranus and they all say 98.6F, I have to conclude that you don't have a fever -- despite you protestations that you feel hot, or even the indirect evidence that you are sweaty and your white blood cell count is elevated.

As much of our theories about solar system as you think come from indirect models, much more comes from our examination of the few directly examinable clues that have made their way from space to our planet -- namely meteorites and lunar samples.

We have a name for the belief in theories that have been contradicted by the best available direct physical evidence. It's called superstition.
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greyl Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Aug-29-06 01:42 PM
Response to Reply #81
82. Now, your're posting silliness.
Please feel free to respond to my original main point, rather than fishtailing.
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Fri Aug-25-06 10:44 PM
Response to Reply #5
12. Hmmm...
Careful stated...

"1) The selection criteria involved many factors besides possible fire exposure. Samples representative of typical failure modes or aircraft impact damage were also sought."


http://wtc.nist.gov/progress_report_june04/appendixf.pdf

1. NIST
From the recovered steel, sufficient representative samples from each important class of steel groups are available for a full examination (i.e., chemical, metallurgical, and mechanical property analyses) to investigate why and how WTC 1 and WTC 2 collapsed following the initial impact of the aircraft"

F.6 SUMMARY
NIST has 236 samples from the WTC buildings, the majority belonging to WTC 1 and WTC 2. These samples represent roughly 0.25 percent to 0.5 percent of the 200,000 tons of structural steel used in the construction of the two towers. NIST believes the collection of steel from the WTC towers is sufficient for the Investigation. This assertion is drawn from the following two statements. First, recovery of material from locations in or near the impact and fire damaged regions of WTC 1 and WTC 2 was remarkably good, including four exterior panels directly hit by the airplane and three core columns located within these areas. Second, sufficient representative samples exist for all 14 grades of exterior panel material, 2 grades of the core column material (which represents 99 percent, by total number, of columns), and both grades for the floor truss material.

This report identifies the structural steel elements recovered from the WTC towers. Later reports will determine the physical and mechanical properties of the steels and weld metal and the characteristics of the metal, weldments, and connections from WTC buildings. Additionally, a damage assessment/failures mode examination of the recovered structural steel elements will be performed. This information will be utilized in an effort to determine why and how WTC 1 and WTC 2 collapsed following the initial impact of the aircraft.



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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Fri Aug-25-06 10:56 PM
Response to Reply #12
13. "Three core columns located within these areas"
This might be "good". It is still not representative of the distibution the highest temperature reached by 74 core columns.

Notice that your quote does not contradict anything that I said.
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Fri Aug-25-06 11:42 PM
Response to Reply #13
14. You seem to be misinterpreting..
the NIST report.

Below is the first of the reasons the NIST gives as to why they believe they have a REPRESENTATIVE SAMPLE..

First, recovery of material from locations in or near the impact and fire damaged regions of WTC 1 and WTC 2 was remarkably good, including four exterior panels directly hit by the airplane and three core columns located within these areas.

Recovery of material from locations "in or near the impact" AND "fire damaged regions of wtc 1 and 2 was REMARKARBLY GOOD..included in the GOOD sample (representative sample) we have 4 panels that took a direct hit and three core columns located near said direct hit.

So you see, the NIST actually did have a representative sample, that is of course until the results had contradicted their silly little hypothesis.

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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Sat Aug-26-06 01:42 AM
Response to Reply #14
17. "Representative sample" is a stastistical concept.
"Recovery of material was good" (for many investigation purposes) does not entails that the sample is representative of temperature distributions (just one purpose).

What hypothesis was silly?
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zforce Donating Member (157 posts) Send PM | Profile | Ignore Sat Aug-26-06 01:59 AM
Response to Reply #17
18. I would advise you to take a look..
into what the "investigation' had consisted of in detremining why the structures had failed.

http://wtc.nist.gov/progress_report_june04/chapter2.pdf

---------The collection of steel from the WTC towers is adequate for purposes of NISTs investigation (i.e., chemical, metallurgical, and mechanical property analyses as well as a substantial damage assessment and failure mode examination) to examine why and how WTC 1 and WTC 2 collapsed following the impact of the aircraft and ensuing fires.---------

Does "Metallurgical" ring a bell?

NO?

IF not, then let me help you ring that bell...

http://www.nist.gov/testimony/2002/wtcplan.html

----------Collection and Analysis of Forensic Evidence: structural steel, material specimens and other forensic evidence to the extent they have been collected or are otherwise available; metallurgical and mechanical analysis of steel to evaluate quality and estimate maximum temperatures; analysis of fire and elevator control panels.-----------

BTW, The "fire" hypothesis was silly..
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Grateful for Hope Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Aug-26-06 05:59 AM
Response to Reply #17
23. You are guessing here
and, my interpretation of the NIST comment about their sample is that they were satisfied that the sample was representative of all the variables they considered important to the study - including temperature distributions.

I am sure that NIST was quite aware of what "representative sample" means, as are many of us here.
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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Sat Aug-26-06 05:18 PM
Response to Reply #23
26. You are interpreting here...
You are right that NIST knows what "representative" means, either formally or informally.

NIST never said that their sample was representative of heat exposures. However they did say that it was *not* representative. Their only uses of "representative" are found is statements that the samples are representative (informally) of the types, grades and classes of steel used in the construction -- in cases where they collected all or most of them. Or they say, repeatedly, that the samples are *not* representative (formally) of heat exposure or some types of failure modes when the sample size is too small or the collection method is obviously biased (because they looked specifically for such items) or skewed (because such items were less likely to be found or retained -- e.g. there were often confounding factors or the severe damage impaired the analysis)

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Grateful for Hope Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Aug-26-06 05:33 PM
Response to Reply #26
27. Please provide some links to substantiate what you are saying
Excerpts would do nicely. Thank you in advance.
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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Sat Aug-26-06 05:53 PM
Response to Reply #27
28. Too much work, sorry. However...
Hey, I have to type all this stuff! Copy-paste is disallowed in the NIST pdf doccuments. However the search function works.

Here is what you can do. Scan the NISTCSTAR1-3.pdf document (Mechanical and Metallurgical Analysis of Structural Steel) for all instances of the word "representative". You will find maybe 15-20 relevant instances, all of which exemplify the uses of "representative" (grades, types, etc.) and "not representative" (perimeter or core column temperatures, etc.) that I have explained. There are zero counterexamples.

http://wtc.nist.gov/NISTNCSTAR1-3.pdf

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Grateful for Hope Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Aug-26-06 06:32 PM
Response to Reply #28
29. Thanks for the advice
I wish I had time to do this right now, but, alas, I don't.
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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Sat Aug-26-06 07:37 PM
Response to Reply #29
30. Your're welcome...
When you find the time; it takes two minutes, and it's instructive.

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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Fri Aug-25-06 05:57 PM
Response to Reply #4
6. Column buckling...
The claddings weren't in contact with the steel. They were insulated from it. And a large temperature differential is expected between the inner and outer webs of the columns. This phenomenon in itself promotes buckling.

Yes, a large temperature differential is expected. But from the actual examination of the physical evidence, none was observed.


No. What you agree should have been expected was in fact observed.

Perimeter columns exposed to fire had a greater tendency for local buckling of the inner web than those known to have no exposure. A similar correlation did not exist for weld failure.


From the Executive Summary of this document:
http://wtc.nist.gov/NISTNCSTAR1-3.pdf
p. xlii

This certainly suggests that the fire exposed inner webs expanded critically while they were being restricted by the columns flanges and outer webs.
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mhatrw Donating Member (1000+ posts) Send PM | Profile | Ignore Fri Aug-25-06 07:33 PM
Response to Reply #6
8. Circular reasoning.
First you said the expected large temperature differential promoted buckling. Now you claim that the evidence of buckling shows there was a large temperature differential. Nothing in your logical circle changes the fact that no large temperature differentials were observed in NIST's metallurgical analysis.

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BootinUp Donating Member (1000+ posts) Send PM | Profile | Ignore Fri Aug-25-06 08:23 PM
Response to Reply #8
10. I guess the question is
how much temperature differential would it take to cause the buckling. Perhaps it is less than you imagine.
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Carefulplease Donating Member (749 posts) Send PM | Profile | Ignore Fri Aug-25-06 08:31 PM
Response to Reply #8
11. I didn't make that reasoning...
I agree that moderate fire temperatures might account for the observed buckling. My argument (if you've followed the discussion) was that the aluminum claddings were not to be expected to melt even if the fires were hot.

I also responded to a challenge. Somebody claimed that there were no evidence of buckling due to fires. But there were.


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dailykoff Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Aug-26-06 10:57 AM
Response to Reply #6
25. There was no core column buckling
and any perimeter column buckling was an effect, not a cause, of the top sections toppling, or beginning to.
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dailykoff Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Aug-26-06 10:54 AM
Response to Original message
24. He's absolutely right
and he's got a backbone to boot. Rare in that profession.
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greyl Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Aug-26-06 10:12 PM
Response to Reply #24
32. What profession are you trying to smear the professors of? nt
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Jazz2006 Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Aug-26-06 10:54 PM
Response to Original message
33. He's a Halliburton alumni with no apparent expertise... the truthiness
Edited on Sat Aug-26-06 10:58 PM by Jazz2006
seekers sure seem to be pinning some pretty high hopes on this guy.


It appears that Mr. Pegelow is a Halliburton alumni with no apparent relevant expertise when it comes to buildings or structural engineering.

It was obvious in that interview that he really had little idea what he was talking about and Fetzer kept interrupting when he was afraid that Pegelow would either screw up or say something to hurt the truthiness seeker cause.

It should be interesting to watch what happens next.

:popcorn:


Edit for clarity, couldn't fit everything I wanted to in the subject line so reworded the body of the message.
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