RFC: Bazant and Zhou Simple Analysis refuted

[uk_dave]

I believe it was impossible as there would not have been a dynamic load if the initial collapse was due to fire. One would need a huge dynamic load to cause anything close to a progressive collapse. It just wouldn't be there without other influences like explosives or incendiaries.

The subject of this thread explains that Bazant and Zhou do not have the dynamic load they claim.

So you believe there is not the slightest possibility of the collapse being able to proceed based on the failure witnessed? Not a shred of doubt in your mind?

[pomeroo]

Baloney Ron. You just said a few posts back that they got all of the steel they needed. Well in the report it is obvious that they felt they didn't.

No, typically, you can't manage to quote accurately from a post that just appeared. I am in no position to decide whether or not NIST had access to all the steel it needed. Mike Newman told me that the agency obtained a sufficient amount of steel to conduct its tests. Unlike most fantasists, I am not an authority on all subjects and I can speak only for myself.



Additionally, they made the same type of statement with regard to perimeter columns also. See NIST NCSTAR 1-3C pages xlv and xlvi.

I think people like you who want to call themselves rationalists when making these types of arguments should consider a new handle. I think something along the lines of gulliblists might do.


I think that after of more than six years of screaming, the fantasy movement should produce a single piece of evidence suggesting the existence of its mathematically-impossible conspiracy--the conspiracy whose goal was to transfer control of both houses of Congress from the Republicans to the Democrats--the conspiracy that somehow "forgot" to make a single one of its hijackers an Afghani or an Iraqi--the conspiracy that orchestrated a preposterous Rube-Goldberg operation on 9/11/01, but couldn't plant WMD in Iraq.

I still haven't found the part where NIST complains about not having enough steel. Do you agree that NIST understated its case?

[Tony Szamboti]

Won't work. Most of your blast wave would be along the face of the column not perpendicular. You need to think about the blast wave propagating along the thickness of the charge not radiating out equally in all directions. What you describe would give you a nice black mark on the column and a big noise.

I guess I don't understand what you are saying.

I believe that a wide flat plastic charge, which is tamped, would send most of its explosive force into the column. I am also wondering if the charge could have been placed at the edges of the column as that area would be stiffened by the end plate and transmit most of the force to the welds.

[Gravy]

GIANTS WIN!!!

Okay, Tony: you've had enough time to concoct any number of lame, denialist, weasel excuses for your completely contradictory statements, OR to adjust your beliefs to match reality.

Which is it? Go.

[beachnut]

I guess I don't understand what you are saying.

I believe that a wide flat plastic charge, which is tamped, would send most of its explosive force into the column. I am also wondering if the charge could have been placed at the edges of the column as that area would be stiffened by the end plate and transmit most of the force to the welds.
Would never see that blast!? FWZBRWQXs6g Very silent stuff. No real blast effects. realcddeal still is short evidence.

Where are the blasts like this on 9/11?

[Heiwa]

Show something specific that NIST got wrong. Show us where the conclusions are contradicted by the data.



From NIST report - NISTNCSTAR1-6D chapter 5.2 - we learn:

"The aircraft impacted the north wall of WTC 1 at 8:46 a.m. … between Floor 93 and Floor 98. … The subsequent fires weakened structural subsystems, including the core columns, floors and exterior walls. The core displaced downward … At 100 min (at 10:28:18), the north, east, and west walls at Floor 98 carried 7 percent, 35 percent and 30 percent more gravity load loads … and the south wall and the core carried about 7 percent and 20 percent less loads, respectively., … At 10.28 a.m., 102 min after the aircraft impact, WTC1 began to collapse. … The release of potential energy due to downward movement of the building mass above the buckled columns exceeded the strain energy that could be absorbed by the structure. Global collapse ensued."

The highlighted items are not proven.

The potential energy in the building only stressed it statically 20-30% of yield. If that energy is released it should fall to the ground!

It has nothing to do with the strain energy that could be absorbed by the structure, which, BTW, is not calculated by NIST!

Evidently a fair amount of any potential energy released = kinetic energy can be absorbed by the structure, if applied to it, and a static condition is re-established after e.g. local collapse of some supporting members= no further collapse.

So there is no evidence that global collapse ensues for the alleged cause and effect.

Above applies to WTC1. NIST suggests a copy/paste cause/effect for WTC2 even if damage there was in another location and size.

NIST suggests that the potential energy of the mass above was released when all columns in the initiation zone simultaneosuly failed. No evidence for that. It is clear from all evidence that the mass above moved when all visible columns below were intact!

It is then assumed that all the potential energy thus released and transformed into kinetic energy then IMPACTED other structure. No evidence for that.

And it is only if there is an IMPACT that strain energy of structure is of interest.

The above error on one page of the NIST report disqualifies the 10 000 other pages.

[Heiwa]

This thread went dead after my message #506! So I assume you all agree that the NIST report is wrong.

[GregoryUrich]

Anyone remember the opening topic?

I'll give some clues. It's not controlled demolition. It's not any and all errors in NIST. It's not opinions about other members. If you want to talk about these, PLEASE START NEW THREADS.

Here are some new issues related to the OT:

My derivation of Pdyn has a mistake resulting in an incorrectly low overload ratio. I incorrectly applied the 1/2 energy factor to only the potential energy components and not the strain energy.

I accept MT's arguments regarding Bazant's failure mode and initiation being incorrect, but I will deal with them in the introduction and discussion. I do this because the Bazant and Zhou "simple analysis" model and conclusions will most likely be refuted on their own without challenging every assumption.

Newtons Bit's strain energy calculations seem to have an error giving only 1/2 the strain energies. His derivation uses Pi/12 = 30 degrees, but Pi/12 = 15 degress.

I think these two issues will essentially cancel each other out. However, there are other issues regarding strain energies and I know Tony has some comments on this. Maybe we could first try to deal with the strain energies and then I can fix the two known issues and see where we land.

[GregoryUrich]

You're assuming a continuous taper to the columns, which wasn't actually the case. The column section changed stepwise at certain floors - I forget which, but AFAIR they were well below 97. There wasn't therefore any difference between the column profiles in the upper and lower blocks in the initial stages. That would suggest simultaneous crush up / crush down as a first approximation. For a better approximation you'd want to look at the boundary conditions for termination of the elastic shock wave at the free upper end of the upper block and the fixed lower end of the lower block; which gives higher reflection? The reflected elastic wave will contribute to the destruction of the structure fairly early on in the process.

...snip

As can be seen at:

http://wtcmodel.wikidot.com/nist-core-column-data

the core columns tapered quite linearly (every three floors) except for the bottom and topmost parts. The absolute weakest part of the core was floors 105-106. There was a transtition at floor 98 to 20-30% weaker columns. The force in the columns of the lowest floor of the upper part is only slightly less than the force applied to the lower part due to the weight of the lowest floor only acting only the lower part. This difference is 1/14 as opposed to the difference in strength which is at least 1/5. Using B&Z's primary assumption, the upper part most likely fails first, sparing the lower part.

I'm open to input regarding reflection, but it needs to be quantified through a reasonable modeling of the foundation including the baseplates and grillages as well as calculating how much energy gets transmitted to the ground. Losses due to damping should also probably be considered.

[twinstead]

This thread went dead after my message #506! So I assume you all agree that the NIST report is wrong.

I think you have no idea what an 'error' is, nor do you have any idea why the page you referenced, which in YOUR opinion doesn't have any evidence to support it, does indeed NOT 'invalidate the other 10,000 pages'.

You've already shown yourself incapable, in both expertise AND ideological bias, of investigating where you left your car keys let alone whether the NIST report contains errors or not.

Now, if we can get back to the topic I can continue to read stuff by people who actually know what they are talking about and learn a few things. In the mean time I'll defer to REAL experts to help me understand the NIST report.

[SDC]

This thread went dead after my message #506! So I assume you all agree that the NIST report is wrong.

Most of the people posting around here are in North America. In my area (Eastern time zone) you posted 506 at 1:23 am and then proclaimed your glorious victory at 5:41 am.

Hint: most people are asleep at those times. Or in any case, not on line.

[bje]

Most of the people posting around here are in North America. In my area (Eastern time zone) you posted 506 at 1:23 am and then proclaimed your glorious victory at 5:41 am.

Hint: most people are asleep at those times. Or in any case, not on line.


You assume Heiwa understands time zones - zones other than twilight zones.

[GregoryUrich]

Bump. PLEASE STAY ON TOPIC!

Anyone remember the opening topic?

I'll give some clues. It's not controlled demolition. It's not any and all errors in NIST. It's not opinions about other members. If you want to talk about these, PLEASE START NEW THREADS.

Here are some new issues related to the OT:

My derivation of Pdyn has a mistake resulting in an incorrectly low overload ratio. I incorrectly applied the 1/2 energy factor to only the potential energy components and not the strain energy.

I accept MT's arguments regarding Bazant's failure mode and initiation being incorrect, but I will deal with them in the introduction and discussion. I do this because the Bazant and Zhou "simple analysis" model and conclusions will most likely be refuted on their own without challenging every assumption.

Newtons Bit's strain energy calculations seem to have an error giving only 1/2 the strain energies. His derivation uses Pi/12 = 30 degrees, but Pi/12 = 15 degress.

I think these two issues will essentially cancel each other out. However, there are other issues regarding strain energies and I know Tony has some comments on this. Maybe we could first try to deal with the strain energies and then I can fix the two known issues and see where we land.

[Heiwa]

Most of the people posting around here are in North America. In my area (Eastern time zone) you posted 506 at 1:23 am and then proclaimed your glorious victory at 5:41 am.

Hint: most people are asleep at those times. Or in any case, not on line.

Actually I wrote it for US media - never sleeping? - so they could announce it in the local morning news ECT, etc. But they appear to be still sleeping. Sorry for disturbing your sleep. Back to topic. Is the relevant NIST statement about cause and effect - The release of potential energy due to downward movement of the building mass above the buckled columns exceeded the strain energy that could be absorbed by the structure. Global collapse ensued - true? This is one basic assumption of the Gurich paper, that is the topic.

[Newtons Bit]

Anyone remember the opening topic?

I'll give some clues. It's not controlled demolition. It's not any and all errors in NIST. It's not opinions about other members. If you want to talk about these, PLEASE START NEW THREADS.

Here are some new issues related to the OT:

My derivation of Pdyn has a mistake resulting in an incorrectly low overload ratio. I incorrectly applied the 1/2 energy factor to only the potential energy components and not the strain energy.

I accept MT's arguments regarding Bazant's failure mode and initiation being incorrect, but I will deal with them in the introduction and discussion. I do this because the Bazant and Zhou "simple analysis" model and conclusions will most likely be refuted on their own without challenging every assumption.

Newtons Bit's strain energy calculations seem to have an error giving only 1/2 the strain energies. His derivation uses Pi/12 = 30 degrees, but Pi/12 = 15 degress.

I think these two issues will essentially cancel each other out. However, there are other issues regarding strain energies and I know Tony has some comments on this. Maybe we could first try to deal with the strain energies and then I can fix the two known issues and see where we land.

Oops. There goes my factor of conservative in favor of collapse prevention. There's also another error in the calculation, in that the degree of rotation of the middle hinge is actually half of the top and bottom hinges, but fixing that one seems more trouble to explain it than to just get a lower number.

[WildCat]

Actually I wrote it for US media - never sleeping? - so they could announce it in the local morning news ECT, etc.
:dl:

[GregoryUrich]

Oops. There goes my factor of conservative in favor of collapse prevention. There's also another error in the calculation, in that the degree of rotation of the middle hinge is actually half of the top and bottom hinges, but fixing that one seems more trouble to explain it than to just get a lower number.

Isn't the degree of rotation for the middle hinge twice the top or bottom? That would give us a factor of 4Pi/6 (using 30 deg).

[Newtons Bit]

Isn't the degree of rotation for the middle hinge twice the top or bottom? That would give us a factor of 4Pi/6 (using 30 deg).

You measure the rotation from the horizontal. If the top and bottom would be 30 degrees, the middle one would actually rotate 60 degrees, this is true. However you would only use 30 degrees for the strain energy calc of the middle hinge.

It's not going to undergo 30 degrees of rotation.

Ooh Oooh, I could use this to show that I never really had a mistake after all! :D :D

[Major_Tom]

Myriad asks:

What is the evidentiary basis for doubting their expertise?

Collapse initiation in both buildings is perhaps the most profound engineering question there is.


Millions of follow human beings have sincere questions regarding the suspicious circumstances behind the collapses.


I'd say that any structural engineer worth his salt would want to know what possible design flaws lead to collapse initiation, if any.




Within this context, how is it possible that no photographic record is kept of the core columns from the collapse initiation zone?


Why do you ask that I share your "faith"?

Why not just show me some of these buckled columns?



Possibly the most fascinatiing structural failures ever and we can't photograph the 100 or so pieces of metal that initiated them?



"Mangled" columns are no longer an excuse, for the columns, both core and perimeter, were remarkably well-preserved.



Call me a skeptic.

And 6 years on, you ask why I don't share your faith?

[SDC]

MT's comments really come down to, "why didn't they prepare to study the collapse before it happened?" It's time to dance the Time Warp.

[WildCat]

I'd say that any structural engineer worth his salt would want to know what possible design flaws lead to collapse initiation, if any.
Absolutely. And so far the total number of structural engineers who doubt that the buildings collapsed without bombs is near zero.

Lots of kooks without any engineering experience with tall buildings whatsoever are questioning it though...

[Major_Tom]

Why is faith necessary? It is an investigative body, not a diety.

[GregoryUrich]

Myriad asks:

Collapse initiation in both buildings is perhaps the most profound engineering question there is.

Millions of follow human beings have sincere questions regarding the suspicious circumstances behind the collapses.

I'd say that any structural engineer worth his salt would want to know what possible design flaws lead to collapse initiation, if any.

Within this context, how is it possible that no photographic record is kept of the core columns from the collapse initiation zone?

Why do you ask that I share your "faith"?

Why not just show me some of these buckled columns?

Possibly the most fascinatiing structural failures ever and we can't photograph the 100 or so pieces of metal that initiated them?

"Mangled" columns are no longer an excuse, for the columns, both core and perimeter, were remarkably well-preserved.

Call me a skeptic.

And 6 years on, you ask why I don't share your faith?

MT,

Your point has been made. I think it's worth starting a new thread on collapse initiation. However, I would appreciate if we could focus on the OT here. I.e. overload ratio, strain energies, within the boundary of B&Z's primary assumption.

[e^n]

I'm sorry to interrupt your thread again Gregory, i'll make this brief.

Within this context, how is it possible that no photographic record is kept of the core columns from the collapse initiation zone?

Why do you pretend not to know the answer to this when you clearly do? Gravy has repeatedly pointed out that only four columns could be identified. Unless you expect to see a video of the core columns from inside the towers at the moment of collapse how else do you propose such evidence be gathered?.

[Myriad]

Collapse initiation in both buildings is perhaps the most profound engineering question there is.

Millions of follow human beings have sincere questions regarding the suspicious circumstances behind the collapses.

I'd say that any structural engineer worth his salt would want to know what possible design flaws lead to collapse initiation, if any.

Within this context, how is it possible that no photographic record is kept of the core columns from the collapse initiation zone?

Why do you ask that I share your "faith"?

Why not just show me some of these buckled columns?

Possibly the most fascinatiing structural failures ever and we can't photograph the 100 or so pieces of metal that initiated them?

"Mangled" columns are no longer an excuse, for the columns, both core and perimeter, were remarkably well-preserved.

Call me a skeptic.

And 6 years on, you ask why I don't share your faith?


No, I didn't ask why you don't share my evidence-based belief (which you insist on erroneously calling "faith," apparently in order to be provocative) in the competence of engineers. I already know why you don't.

What I asked is, if you don't believe that engineers (more specifically, a panel of 200 top engineers and other experts, inviting commentary and criticism by the rest of their community along the way) can arrive at a generally correct conclusion on the question of why a building collapse occurred, then on what do you rest your hopes that anyone can? If the people who design, build, and inspect skyscrapers are not competent, which you implied when you referred to them as "experts" and "authorities" in scare-quotes, then why shouldn't buildings fall for no known reason?

As for buckled columns in the collapse initiation zone, I've seen photographs showing, all told, hundreds of obviously buckled columns. (I regard any column as "buckled" if it is sufficiently bent that, if one end were aligned with an adjacent vertical member, the other end would be out of true by at least the cross-section width of the column, and thus no longer capable of supporting a vertical load in a space frame. Do you have a different definition of "buckled," and if so, what is it?) Experts who had an opportunity to actually measure the columns reported that thousands more that appear approximately straight in photographs are in fact also buckled to that degree. So, I see photographs of many buckled columns, and I have no reason to believe that some of the columns from the collapse initiation zone would not be among them.

You want photos of individual columns post-collapse from specific positions, even though you know that matching the vast majority of the individual columns to their as-built position was not possible, and a clear explanation of the reasons why have been available to you in the NIST report. Sorry, that means nothing. I could ask every astronomer on earth to show me the far side of the moon through a telescope, and not one of them could do so. Should I conclude that the far side of the moon doesn't exist, or should I listen to their explanation of why it cannot be seen through a telescope from earth? What do you find faulty about NIST's explanation of why most columns could not be matched to their as-built positions in the structure?

@GregoryUrich: I sympathize with your desire to keep the thread on one topic, but after many pages of discussion of other related topics, that ship has sailed. And it wasn't skeptics who introduced those topics or made good "points" in them that are worthy of response. Fortunately, people seem to be having no trouble following the parallel lines of discussion here.

Respectfully,
Myriad

[Heiwa]

I regard any column as "buckled" if it is sufficiently bent that, if one end were aligned with an adjacent vertical member, the other end would be out of true by at least the cross-section width of the column, and thus no longer capable of supporting a vertical load in a space frame. Do you have a different definition of "buckled," and if so, what is it?

"Buckled" of steel structure by definition means bent, twisted or crumpled up and is the key word of the NIST announced only cause/effect of the global collapse: The release of potential energy due to downward movement of the building mass above the buckled columns exceeded the strain energy that could be absorbed by the structure. Global collapse ensued.

Evidently a bent column does not result in much downward movement unless it is bent 180°! A twisted column does not result in any downward movement at all. A crumpled up up column, i.e. compressed into folds or creases, produce downward movement but stops when compression stops.

It is sad that NIST cannot produce any "buckled" column of the initiation zones, be it bent 180° or crumpled up, that would have produced downward motion. We are talking about 566 columns that must have "buckled" for the effect ... and none is found.

[Myriad]

From NIST report - NISTNCSTAR1-6D chapter 5.2 - we learn:

"The aircraft impacted the north wall of WTC 1 at 8:46 a.m. … between Floor 93 and Floor 98. … The subsequent fires weakened structural subsystems, including the core columns, floors and exterior walls. The core displaced downward … At 100 min (at 10:28:18), the north, east, and west walls at Floor 98 carried 7 percent, 35 percent and 30 percent more gravity load loads … and the south wall and the core carried about 7 percent and 20 percent less loads, respectively., … At 10.28 a.m., 102 min after the aircraft impact, WTC1 began to collapse. … The release of potential energy due to downward movement of the building mass above the buckled columns exceeded the strain energy that could be absorbed by the structure. Global collapse ensued."

The highlighted items are not proven.


Hi Heiwa. The quote from NCSTAR above is oddly redacted, with text from a later paragraph inserted out of sequence and some important points removed. Here's the original, with the text pasted in from a later paragraph struck out, and the blanks filled in in blue:

"The aircraft impacted the north wall of WTC 1 at 8:46 a.m. The aircraft severed exterior columns and floors on the north side of the tower and core columns and floor members between Floor 93 and Floor 98. The subsequent fires weakened structural subsystems, including the core columns, floors and exterior walls. The core displaced downward, the floors sagged, and the south exterior wall bowed inward. At 100 min (at 10:28:18), the north, east, and west walls at Floor 98 carried 7 percent, 35 percent and 30 percent more gravity load loads than the state after impact and the south wall and the core carried about 7 percent and 20 percent less loads, respectively. At 10.28 a.m., 102 min after the aircraft impact, WTC1 began to collapse.

The sentence at the end, that you bolded, is actually from two pages later in the report.

This strange editing appears designed to convey several false ideas about what NIST actually said in the paragraph.

- It omitted all mention of the damage caused by the airplane impact, creating the false impression that NIST is attributing the effects that follow solely to "the subsequent fires."

- It omits the sagging of the floor and the buckling of the wall, creating the false impression that the downward displacement of the core was the individual initiating event, instead of occurring along with other changes in the structure. Actually, the report is quite clear that the instability that initiated the collapse "started at the center of the south wall and rapidly progressed horizontally to the sides." (Pg. 314)

- It omits the phrase "than the state after impact" from the section pasted in from a later paragraph, creating the false impression that the figures given from increased loads were increases over the original building loads, instead of increases over the already increased and unbalanced loads experienced as a result of the impact damage.

- It inserts and appends sentences from later paragraphs, out of sequence, obfuscating the five-stage sequence that the report actually delineates very clearly.

NIST suggests that the potential energy of the mass above was released when all columns in the initiation zone simultaneosuly failed. No evidence for that. It is clear from all evidence that the mass above moved when all visible columns below were intact!


The edited version you posted suggests that, yes. But the original report says:

Instability started at the center of the south wall and rapidly progessed horizontally toward the sides. As a result of the buckling of the south wall, the south wall was significantly unloaded (Fig 5-3), redistributing its load to the softened core through the hat truss and to the south side of the east and west walls through the spandrels. ... The section of the building above the impact zone tilted to the south (observed at about 8°, Table 5-2) as column instability progressed rapidly from the south wall to the adjacent east and west walls (see Fig. 5-8), resulting inn increased gravity load on the core columns.

That is not a simultaneous failure, though it was a rapidly progressing one. Why was the paragraph edited to suggest something that the original report did not suggest?

It is then assumed that all the potential energy thus released and transformed into kinetic energy then IMPACTED other structure. No evidence for that.

And it is only if there is an IMPACT that strain energy of structure is of interest.


Kinetic energy and strain energy are relevant factors as long as there is movement, which there was, specifically an 8° tilt, in NIST's Event 5. "Impact" is not mentioned in the NCSTAR chapter being referenced here, so no "assumption" of impact was made. It's not NIST's fault that the edited paragraph you posted rearranged the text to juxtapose a statement regarding movement of the structure, and consequent kinetic and strain energies, with the fire-weakening effects they describe in Events 3 and 4.

The above error on one page of the NIST report disqualifies the 10 000 other pages.


Who edited the report to introduce those errors, and why? I'd say that disqualifies the person who moved the words around, rather than the actual report.

Respectfully,
Myriad

[Myriad]

"Buckled" of steel structure by definition means bent, twisted or crumpled up and is the key word of the NIST announced only cause/effect of the global collapse: The release of potential energy due to downward movement of the building mass above the buckled columns exceeded the strain energy that could be absorbed by the structure. Global collapse ensued.


Several engineering glossaries I consulted all defined "buckle" the same way: "To bend under compression." None specify any minimum angle of bending for the term to be applicable.

Most of the columns were measurably bent, many of them to a degree that's easily visible even in photographs. So, there are plenty of photographs of buckled columns.

Evidently a bent column does not result in much downward movement unless it is bent 180°!


What nonsense. A few minutes of elementary trig tell me that a column that's buckled into a circular arc so that it is phi degrees out of true where phi <= 45° (hence forming an arc of angle 2*phi with a radius of curvature of L * tan(2*phi) where L is the original column length) results in downward movement of at least L * (1 - cos(phi)). The column is shortened by a factor of cos (phi). If one end is fixed to the vertical the downward movement is increased to L * sin (phi) * sin (2*phi), with lateral movement of L * sin (phi) * cos (2*phi). Less uniform bends would have larger effects.

It is sad that NIST cannot produce any "buckled" column of the initiation zones, be it bent 180° or crumpled up, that would have produced downward motion. We are talking about 566 columns that must have "buckled" for the effect ... and none is found.


If you really think that a column must be bent 180 degrees or crumpled up to be buckled, then it's no wonder that NIST cannot produce any that satisfy you. The problem is simply that you misunderstand what "buckled" means.

Respectfully,
Myriad

[beachnut]

Anyone remember the opening topic?

I'll give some clues. It's not controlled demolition. It's not any and all errors in NIST. It's not opinions about other members. If you want to talk about these, PLEASE START NEW THREADS.

Here are some new issues related to the OT:

My derivation of Pdyn has a mistake resulting in an incorrectly low overload ratio. I incorrectly applied the 1/2 energy factor to only the potential energy components and not the strain energy.

I accept MT's arguments regarding Bazant's failure mode and initiation being incorrect, but I will deal with them in the introduction and discussion. I do this because the Bazant and Zhou "simple analysis" model and conclusions will most likely be refuted on their own without challenging every assumption.

Newtons Bit's strain energy calculations seem to have an error giving only 1/2 the strain energies. His derivation uses Pi/12 = 30 degrees, but Pi/12 = 15 degress.

I think these two issues will essentially cancel each other out. However, there are other issues regarding strain energies and I know Tony has some comments on this. Maybe we could first try to deal with the strain energies and then I can fix the two known issues and see where we land.
Yep, and you are attacking a model because you can not find silent RDX, thermite evidence, or real facts to support your failed ideas on 9/11. Yep, you are attacking a model! You could just email those guys so they can be happy you are not a peer. Your peers are 9/11 truth. Wow

Yes you have given up on RDX, it is too noisy (no evidence), too much blast (no blast evidence on steel), too much fantasy. So you wrote a paper to attack a model, and you do not even have a clue how much weight a single floor can hold. Have you talked to Robertson about this; I mean with you and your peer reviewed paper, he should talk to you?
Have you talked to the Washington Post or New York Times?
Have you done anything? With evidence like this, a simple model may be wrong. You should have something! But let me explain, the model is useful for a few reasons and you have failed to fine one of them. Failure is yours, you have failed to make this public in a big way, you have failed to find your silent explosives, and remember the big problem! Jones woke up one day 4 years after 9/11 and made up thermite as he was dropping Cinderblocks 10 feet to simulate the concrete in the WTC being dustified! Cool

[Heiwa]

Evidently I do not quote several pages of unproven observations - just some relevant ones. NIST tries to convey the message that 'buckling' was sudden and everywhere in the 4 000 m² large intitiation area, height of which for WTC1 - subject of my article - is not given. And NIST intentionally leaves 'buckling' vague to mislead the readers. And this strange buckling of columns shall cause release of potential energy of the mass above.

However, when I look at videos of WTC1 the roof moves downward several meters ... and no visible columns are 'buckled'. And none is found in the rubble.

And this release of potential energy - roof moving down several meters - is very slow!! It takes a couple of seconds. But suddenly the mass above the initiation zone explodes ... and the roof falls very quick.

But no real sign of any buckled columns at that moment.

And what the amount of potential energy released has to do with the strain energy in the intact structure is beyond me. NIST fails completey to explain what happens with the potential energy after it was released! It becomes kinetic energy ... and then what? An impact? Not seen anaywhere. And this little kinetic energy destroys the whole tower?

I would expect it to be arrested (consumed by the 'buckling' of columns) and diverted and absorbed by the intact structure and that the mass above rested on it with some lose parts falling down beside.

[WildCat]

This strange editing appears designed to convey several false ideas about what NIST actually said in the paragraph.
Of course it was, because Heiwa is a liar as are the rest of the charlatans and frauds that make up the "truth" movement.

[Newtons Bit]

Isn't the degree of rotation for the middle hinge twice the top or bottom? That would give us a factor of 4Pi/6 (using 30 deg).

You only use half the rotation of the total on the middle hinge as it takes half the work to rotate it as the top and bottom hinges.

If you want to get as accurate as you can for the strain energy from the plastic hinges - ignoring the fact that 1/3rd of the exterior columns have a splce at a plastic hinge - I recommend using 6 degrees of rotation at the hinges. The top and bottom hinges will rotate 6 degrees when the middle hinge rotates 12 degrees. 12 degrees is about the limit that a room-temperature hot-rolled shape can undergo before it begins to tear. That's 0.4188 radians total (you should check that :D).

It is worth noting that the exterior columns that showed large amounts of bending inwards did so only because they were hot. If they were cold, they wouldn't be able to bend as far as they did without breaking. And if they were cold, they wouldn't have bent inwards at any noticeable degree.

[rwguinn]

Of course it was, because Heiwa is a liar as are the rest of the charlatans and frauds that make up the "truth" movement.
You think that you, myriad, and especially Heiwa could take it to a new thread, or ressurect one of the ones that showed lie of all this crap years ago?
Better yet, put the ijits on ignore.

Next derail will get reported.

[Major_Tom]

Most of the columns were measurably bent, many of them to a degree that's easily visible even in photographs. So, there are plenty of photographs of buckled columns.


Verifiably untrue.


You've captured the essense of the misunderstanding.

This is the untruth that the Bazant model relies upon.

This is the untruth that you require to explain collapse initiation.



Nobody has any excuse but laziness not to verify for themselves whether the above statement is true or not.

[Apollo20]

Well, there is the excuse that they are JREFers

[Myriad]

Most of the core columns recovered were significantly deformed, which made it difficult to select undeformed regions to harvest test specimens from. Even the relatively straight sections were often slightly bent.NIST NCSTAR 1-3D "Mechanical properties of structural steel," page 48 (82 in the PDF).

Photos? Sure. The first image I found, picking a site at random from a search on "photographs wtc columns", was this: http://911research.wtc7.net/wtc/arch/docs/image5.jpg Ignore the obviously buckled I-beams; the issue is core columns, like the one running horizontally behind the workman. Lay a straightedge against the edges of that column. Is it straight?

No bent columns here:
http://forums.randi.org/imagehosting/1301247955c05aa48d.jpg
Oh, wait...

Tom, I look forward to your verification of the untruth of the statement, "Most of the columns were measurably bent, many of them to a degree that's easily visible even in photographs. So, there are plenty of photographs of buckled columns."

Respectfully,
Myriad

[einsteen]

Heiwa,

My conclusion is that collapse initiation can be proved in 1d only if there is initial movement and a homogenous force during a distance h (of a story), if there is no initial movement it is impossible. Since it is believed that it was a slow process one could use v1>0 in the homogenous 1d model. But for a more realistic model, in which the force grows and drops it is impossible. even with a small v1>0. The 1d papers that show that the collapse continues are not able to prove initiation, they have to assume it. I agree with you.

[Heiwa]

I like Gurich's paper about overload caused by the mass above on the structure below.

The mass above is of course a hotch potch of structural items so it easiest just to look at one of them and apply the theory to it, e.g. core column #501

It is an H-beam with two flanges 17x3.5 inch connected by a 2.2x12.6 inch web.

In metric terms the flanges are 430x90 mm and the web is 56x320 mm. The cross area is about 950 cm², i.e. the column is very solid. It weighs 750 kgs/m. It may carry as much as 700 tons transmitted to it from the floors above, i.e. each floor above transmits about 50 tons to the column through bolted connections.

The compressive stress in this core column at floors 94-98 is then abt 736 kgs/cm² or 74 MPa or 30% of the yield stress of the steel. The (smallest) moment of inertia I of this section is about 120 000 cm4 and its radius of gyration is of the order 35 cms. With a free length of 350 cms the slenderness ration is 10! Removing three floors as support and the free length is 1 400 cms and the slenderness ratio is still only 40! The thick steel plates, 56 and 90 mm cannot buckle under any circumstance when the compressive stress is only 30% of yield stress even if the temperature is 500°C.

Anyway our humble experts at NIST suggest that a part of this column 'buckles' - probably it bends - in the initiation zone and then disappears (none has been found) so that the upper, top part - 700 tons - most of it floors bolted to it, drops down on the lower part - and hits it with an impact force!

NIST thus assumes that the upper part of one column hits the lower part of the same column without missing it. What happens then? I would assume that most bolted floor connections of the upper part shear off due to the impact.

And that should be the end of it. Hostile comments are always welcome as the houris await me in Paradise.

PS There are many photos of a woman standing waving on floor 93 of WTC 1 at the hole in the North wall. Not far behind her, inside WTC1 is core column #501.

[bje]

PS There are many photos of a woman standing waving on floor 93 of WTC 1 at the hole in the North wall. Not far behind her, inside WTC1 is core column #501.


...and WTC 1 was still standing at that point.

Ooops.

[Heiwa]

...and WTC 1 was still standing at that point.

Ooops.

The tragedy is that this woman apparently walked through the burning initiation zone inferno, according NIST, where red hot columns were being 'buckled' and walls were tipping, and she had no fear. And slowly the whole mass above dropped down and crushed her.

[bje]

The tragedy is that this woman apparently walked through the burning initiation zone inferno, according NIST, where red hot columns were being 'buckled' and walls were tipping, and she had no fear. And slowly the whole mass above dropped down and crushed her.


You would, of course, be able to provide the citation in NIST of what she "walked through", right, Heiwa?

Let's see it.

[Apollo20]

Actually there is a later photo of that brave woman, Edna Cintron(?), falling to her death. I suspect she fell to escape the heat.....

[WildCat]

The tragedy is that this woman apparently walked through the burning initiation zone inferno, according NIST, where red hot columns were being 'buckled' and walls were tipping, and she had no fear. And slowly the whole mass above dropped down and crushed her.
This confirms that you area despicable liar! There are fires raging above and below her, obvious even in this 2 sec. video. And she is clearly terrified:
glWYTfbOi6Q

[Heiwa]

This confirms that you area despicable liar! There are fires raging above and below her, obvious even in this 2 sec. video. And she is clearly terrified:
glWYTfbOi6Q

There are plenty of videos of the woman in the damaged wall and there is very little fire. The point is that the very strong core column #501 is just 15 metres behind her. And she was probably standing on floor 94.

[WildCat]

There are plenty of videos of the woman in the damaged wall and there is very little fire.
This is another lie Heiwa. The fires are raging in every video of Edna Cintron. "Truthers" like to show only a zoomed-in portion of the video to "prove" that there were no fires. It's another example of the lies and misinformation that is the lifeblood of the "truth" movement. Edna was trapped by the fires, it takes quite a bit of desperation for someone to perch precariously 1000 feet above ground as she was. She wasn't there to wave "hi mom" for the TV cameras. She was terrified, and likely knew she was only buying time for the inevitable.

The way "truthers" are using her desperate predicament is disgusting.

[DGM]

There are plenty of videos of the woman in the damaged wall and there is very little fire. The point is that the very strong core column #501 is just 15 metres behind her. And she was probably standing on floor 94.
Why don't you take your junk to a new thread?
Maybe call it the "Heiwa hallucinations and other delusions thread"

Stop derailing this thread. You have been reported.

[Dave Rogers]

The tragedy is that this woman apparently walked through the burning initiation zone inferno, according NIST, where red hot columns were being 'buckled' and walls were tipping, and she had no fear.

Heiwa, if you're that certain of Edna Cintron's mental state at that precise moment, you should be applying for Randi's millions. I wanted to say something about you being a revolting, loathsome excuse for a human being, but that would be attacking the person rather than the argument; however, you should maybe consider the possibility that your above statement suggests such an appalling lack of empathy that it's unlikely to win you many allies among the sane.

Dave

[Pookster]

... and she had no fear ...

Standing at the edge of a very large open hole (that she may or may not have known the cause for) with extensive damage in most directions she would have looked inside the building ... at around the 94th floor ... with smoke clearly visible to her if she looked up or down from that ledge, likely having seen dead bodies and/or body parts as she moved to that ledge ...

and you want to claim she had "no fear"?

Seriously?

I was afraid for her just seeing the images after the fact. If anything, fear of dying was the order of the day on 9/11. What makes her an exception? Her actions speak of someone wanting desperately to find a way out of that building.

[Pookster]

Heiwa, if you're that certain of Edna Cintron's mental state at that precise moment, you should be applying for Randi's millions. I wanted to say something about you being a revolting, loathsome excuse for a human being, but that would be attacking the person rather than the argument; however, you should maybe consider the possibility that your above statement suggests such an appalling lack of empathy that it's unlikely to win you many allies among the sane.

Dave

I'd say it too, along with a few more choice words. But, I agree it would be attacking the person rather than the argument.

[bje]

The point is that the very strong core column #501 is just 15 metres behind her. And she was probably standing on floor 94.


Still waiting for your citation from NIST, Heiwa. Having trouble coming up with one?

[Heiwa]

Why don't you take your junk to a new thread?
Maybe call it the "Heiwa hallucinations and other delusions thread"

Stop derailing this thread. You have been reported.

The thread is about the Bazant/Zhou analysis. I suggest the author simplify by, e.g. only applying the analysis to one column, #501, and provide some info about that. No hallucinations. Very strong column to say the least. And it cannot collapse according to any known theory. Can, e.g. be shown in appendix. I look forward to Gurich final paper.

[funk de fino]

The thread is about the Bazant/Zhou analysis. I suggest the author simplify by, e.g. only applying the analysis to one column, #501, and provide some info about that. No hallucinations. Very strong column to say the least. And it cannot collapse according to any known theory. Can, e.g. be shown in appendix. I look forward to Gurich final paper.

The stupid gets worse

[uk_dave]

The stupid gets worse

I think he means it could only sink. :confused:

[Heiwa]

The stupid gets worse

On the contrary. NIST/Bazant suggest that the whole top part above dropped down on the whole structure below because all structure in the initiation zone disappeared ... or 'buckled'. And then there was global collapse. No evidence for anything, of course. 'Buckled'? What do they mean? Gurich tries to clarify the matters.

That the whole 4000 m² large and several storeys high initiation zone 'buckled'? And then disappeared? So that the top part could start to drop and release potential energy? That is really stupid. I know, most Americans believe it, but really? Can't they look at the videos?

Anyway, as suggested politely, it is easier just to look at one column, e.g. #501 in the initiation zone and see what could have happened to it using the proposed theory. Where did it disappear?

[uk_dave]

Silly engineers. Fancy designing towers with all those unnecessary extra columns and wasting clients money on fireproofing.

Tsk tsk. Amateur structural engineers ROCK!

[Heiwa]

Silly engineers. Fancy designing towers with all those unnecessary extra columns and wasting clients money on fireproofing.

Tsk tsk. Amateur structural engineers ROCK!

Not at all. It is called redundancy. Quite necessary in the real world. Nobody is perfect, except NIST and Bazant, of course, but their supporters seem only to be believers of various types of hope, trust and confidence in ... nothing. OT of course, Back to T. Why cannot anybody explain why core column #501 disappeared?

[SDC]

Not at all. It is called redundancy. Quite necessary in the real world. Nobody is perfect, except NIST and Bazant, of course, but their supporters seem only to be believers of various types of hope, trust and confidence in ... nothing. OT of course, Back to T. Why cannot anybody explain why core column #501 disappeared?

Well, we don't like to discuss it, but core column #501 had stepped out for coffee and a donut when the plane struck. He wasn't able to get back in time, and as a result the whole building came down.

Of course, considering the nationality of so many of NYC's coffee vendors (hint: they all seem to be named "Abdul" or "Mohammed"), there are suspicions that it was a ... dare I say it? Yes! inside job!!

[DGM]

Not at all. It is called redundancy. Quite necessary in the real world. Nobody is perfect, except NIST and Bazant, of course, but their supporters seem only to be believers of various types of hope, trust and confidence in ... nothing. OT of course, Back to T. Why cannot anybody explain why core column #501 disappeared?
Divers cut it off after the collapse. Of course they were later killed so they couldn't talk.

[Myriad]

Evidently I do not quote several pages of unproven observations - just some relevant ones.

No, you (or whoever you might have copied the modified NIST paragraph from) did not edit the text to omit irrelevant portions. You changed the order of sentences, and you removed specific phrases to change the meaning and implications of what remained. Let's look at this again. Here is what you stated in your post:

From NIST report - NISTNCSTAR1-6D chapter 5.2 - we learn:

"The aircraft impacted the north wall of WTC 1 at 8:46 a.m. … between Floor 93 and Floor 98. … The subsequent fires weakened structural subsystems, including the core columns, floors and exterior walls. The core displaced downward … At 100 min (at 10:28:18), the north, east, and west walls at Floor 98 carried 7 percent, 35 percent and 30 percent more gravity load loads … and the south wall and the core carried about 7 percent and 20 percent less loads, respectively., … At 10.28 a.m., 102 min after the aircraft impact, WTC1 began to collapse. … The release of potential energy due to downward movement of the building mass above the buckled columns exceeded the strain energy that could be absorbed by the structure. Global collapse ensued."


And here is the original paragraph from the NIST report:

"The aircraft impacted the north wall of WTC 1 at 8:46 a.m. The aircraft severed exterior columns and floors on the north side of the tower and core columns and floor members between Floor 93 and Floor 98. The subsequent fires weakened structural subsystems, including the core columns, floors and exterior walls. The core displaced downward, the floors sagged, and the south exterior wall bowed inward. At 10.28 a.m., 102 min after the aircraft impact, WTC1 began to collapse.

[from a later page]: "At 100 min (at 10:28:18), the north, east, and west walls at Floor 98 carried 7 percent, 35 percent and 30 percent more gravity load loads than the state after impact and the south wall and the core carried about 7 percent and 20 percent less loads, respectively."


As before, the blue text is the text that was removed in the process of (you claim) collecting "relevant" passages.

At one point five words are removed to completely change the apparent meaning of the statement. That is not editing for brevity, it is attempted deception. Fortunately such deception cannot succeed, because anyone can compare the modified sentences with the originals in the report. Another removed passage describes the damage from the airplane crash. If you indeed regard that damage as "irrelevant," you are very much mistaken, and obviously so. Severed exterior members, core columns, and floor members are in fact highly relevant to a structural collapse initiated at the same floors where that damage had occurred.

And NIST intentionally leaves 'buckling' vague to mislead the readers.


There is nothing vague about the term. If you didn't understand it correctly that was not NIST's fault. Their documents are technical reports for a technically proficient audience.

NIST suggests that the potential energy of the mass above was released when all columns in the initiation zone simultaneosuly failed.


NIST did not suggest anything of the sort. They describe a progressive failure. Again, anyone can see what NIST actually stated outright (not suggested) by referring to the original report:

Instability started at the center of the south wall and rapidly progessed horizontally toward the sides. As a result of the buckling of the south wall, the south wall was significantly unloaded (Fig 5-3), redistributing its load to the softened core through the hat truss and to the south side of the east and west walls through the spandrels. ... The section of the building above the impact zone tilted to the south (observed at about 8°, Table 5-2) as column instability progressed rapidly from the south wall to the adjacent east and west walls (see Fig. 5-8), resulting in increased gravity load on the core columns. (NISTNCSTAR1-6D. Pg. 324)

And what the amount of potential energy released has to do with the strain energy in the intact structure is beyond me. NIST fails completey to explain what happens with the potential energy after it was released! It becomes kinetic energy ... and then what? An impact? Not seen anaywhere. And this little kinetic energy destroys the whole tower?


If the relationship between the strain energy and the potential energy is indeed beyond you (and I'll take your word on it), then perhaps you should study the subject some more before pronouncing conclusions about it. Just a suggestion.

I would expect it to be arrested (consumed by the 'buckling' of columns) and diverted and absorbed by the intact structure and that the mass above rested on it with some lose parts falling down beside.


Let's suppose that, in some alternate universe, that did indeed happen. Imagine the energy absorbed as strain by buckling columns brought the upper mass to a stop, with the 99th floor pan resting against the 98th floor pan along the south wall, the north wall columns still upright, and the east wall, west wall, and core buckled to reduce their vertical span by (on average) half a story, or 6 feet (more toward the south, less toward the north).

The question is, could this structure possibly stand? I don't know for certain, but it would take real calculations in three dimensions by a real structural engineer to convince me that it could. The top would be tilted 3.3 degrees, causing the south wall columns above the break to no longer align, either in position or angle, with south wall columns below. Instead, these columns (bearing a greater share of the load than normal, because of the tilt) now bear on the 98th floor pan. Due to the tilt, all the columns above and below are now subject to lateral forces. The angle is small so these lateral forces are not large compared to the vertical ones, but the columns were not designed to withstand such lateral forces at all, and they're already buckled and so only have a small fraction of their capacity at this point. Plus, the original airplane impact damage is still there on the remaining floors, and it's still on fire.

In order for it to remain static (now that we've magically brought it to a halt), it's not enough that the average strength of the remaining members remains above the average loads on them. Instead, every single member must be able to bear the actual load it receives, individually, without buckling. If any one member is overloaded to the point of buckling, it will buckle, and we no longer have a static situation. That is to say, things will start moving again.

If that's the case, it means that actually, they couldn't have come to a stop as hypothesized in the first place.

I like Gurich's paper about overload caused by the mass above on the structure below.

The mass above is of course a hotch potch of structural items so it easiest just to look at one of them and apply the theory to it, e.g. core column #501

It is an H-beam with two flanges 17x3.5 inch connected by a 2.2x12.6 inch web.

In metric terms the flanges are 430x90 mm and the web is 56x320 mm. The cross area is about 950 cm², i.e. the column is very solid. It weighs 750 kgs/m. It may carry as much as 700 tons transmitted to it from the floors above, i.e. each floor above transmits about 50 tons to the column through bolted connections.

The compressive stress in this core column at floors 94-98 is then abt 736 kgs/cm² or 74 MPa or 30% of the yield stress of the steel. The (smallest) moment of inertia I of this section is about 120 000 cm4 and its radius of gyration is of the order 35 cms. With a free length of 350 cms the slenderness ration is 10! Removing three floors as support and the free length is 1 400 cms and the slenderness ratio is still only 40! The thick steel plates, 56 and 90 mm cannot buckle under any circumstance when the compressive stress is only 30% of yield stress even if the temperature is 500°C.


Again, even if your figures are correct, they are meaningless, because you are comparing average loads against yield stress. That assumes the loads are balanced, equally distributed. But averages mean nothing when determining whether failure occurs. It's like saying that because the average income in the U.S. far exceeds the cost of adequate food, no one in the U.S. goes hungry. Because of the airplane impact damage, which you deliberately omitted all mention of from your NIST quote and later excused that omission as not being among the "relevant" facts, the loads were not normally or equally distributed. Failure begins if the load on even one member exceeds its capacity to withstand. At that point, for further collapse not to occur, you must show that the structure can reach a new configuration of redistributed stresses in which every member -- again, not just the average, and not just one column that you pick out, but every single individual member -- is capable of resisting the load on it without buckling. So far, you have not described such a configuration and proven it stable with real calculations of the forces acting on the individual members.

I strongly suggest you read my essay on progressive failure, here: http://forums.randi.org/showthread.php?t=102994. I wrote it with you in mind, because you keep arguing about the impossibility of collapse based on comparing average loads with average capacities. Major Tom might also find it useful.

Anyway our humble experts at NIST suggest that a part of this column 'buckles' - probably it bends - in the initiation zone and then disappears (none has been found) so that the upper, top part - 700 tons - most of it floors bolted to it, drops down on the lower part - and hits it with an impact force!


NIST does not suggest that any columns disappeared (obviously). They could not match specific columns to specific as-built positions, for reasons they explained, but nowhere do they state that columns were absent from the rubble pile. Nor do they describe an "impact" (other than the airplane impact) as being a necessary step in collapse initiation.

NIST thus assumes that the upper part of one column hits the lower part of the same column without missing it. What happens then? I would assume that most bolted floor connections of the upper part shear off due to the impact.


No, NIST does not assume that the upper columns hit the lower part without missing it. Greening, Bazant and Zhou assume that, for the sake of evaluating a simplified scenario as biased against collapse as possible. In reality it is impossible, after a 3.3 degree tilt, for all the columns to directly align with columns below. Instead, columns meet floors, and floors cannot resist large loads concentrated into small areas the way columns can -- which makes reaching a new statically stable configuration, once the upper mass starts moving, even more unlikely.

And that should be the end of it. Hostile comments are always welcome as the houris await me in Paradise.


I hope you do not regard my correcting your errors as hostile. I sometimes pay teachers, editors and proofreaders to correct mine, and I never thought they were being hostile when doing so.

Respectfully,
Myriad

[uk_dave]

I hope you do not regard my correcting your errors as hostile. I sometimes pay teachers, editors and proofreaders to correct mine, and I never thought they were being hostile when doing so.

Respectfully,
Myriad

But it does make one wonder whether Heiwa runs his business in the same..... selective manner.

[Heiwa]

And here is the original paragraph from the NIST report:

"The aircraft impacted the north wall of WTC 1 at 8:46 a.m. The aircraft severed exterior columns and floors on the north side of the tower and core columns and floor members between Floor 93 and Floor 98. The subsequent fires weakened structural subsystems, including the core columns, floors and exterior walls. The core displaced downward, the floors sagged, and the south exterior wall bowed inward. At 10.28 a.m., 102 min after the aircraft impact, WTC1 began to collapse.



How does NIST know that any core columns were severed between floors 93 and 98? Pls provide the evidence. The photos of videos of the poor woman later appearing leaning at some severed exterior columns and standing on floor 94 - not severed - and waving does not show any severe damages inside the WTC1 north wall at all. Look, please. Use your eyes. Use your brain. And do not just believe what some poor NIST employées invent to please their Masters in the hope to please them.

[DavidJames]

...what some poor NIST employées invent to please their Masters in the hope to please them.Okay, so some "NIST employees" are co-conspirators in the murder of 3000 people.

Care to tell us specifically who they are and what you plan on doing to bring justice.

[Pookster]

How does NIST know that any core columns were severed between floors 93 and 98? Pls provide the evidence. The photos of videos of the poor woman later appearing leaning at some severed exterior columns and standing on floor 94 - not severed - and waving does not show any severe damages inside the WTC1 north wall at all. Look, please. Use your eyes. Use your brain. And do not just believe what some poor NIST employées invent to please their Masters in the hope to please them.

Use our eyes and brains? I saw a floor slab missing where there should've been one. You don't consider that severe damage?

[Myriad]

How does NIST know that any core columns were severed between floors 93 and 98?


From http://wtc.nist.gov/oct05NCSTAR1-2index.htm:

In order to estimate the aircraft impact damage to the WTC towers, the following steps were undertaken:

• Constitutive relationships were developed to describe the behavior and failure of the materials under the dynamic impact conditions of the aircraft. These materials included the various grades of steels used in the exterior walls, core columns, and floor trusses of the towers, weldment metal, bolts, reinforced concrete, aircraft materials, and nonstructural contents.
• Global impact models were developed for the towers and aircraft. The tower models included the primary structural components of the towers in the impact zone, including exterior walls, floor systems, core columns, and connections, along with nonstructural building contents. A refined finite element mesh was used for the areas in the path of the aircraft, and a coarser mesh was used elsewhere. The aircraft model included the aircraft engines, wings, fuselage, the empennage, and landing gear, as well as nonstructural components of the aircraft. The aircraft model also included a representation of the fuel, using the smooth particle hydrodynamics approach.
• Component and subassembly impact analyses were conducted to support the development of the global impact models. The primary objectives of these analyses were to (1) develop an understanding of the interactive failure phenomenon of the aircraft and tower components, and (2) develop the simulation techniques required for the global analysis of the aircraft impacts into the WTC towers, including variations in mesh density and numerical tools for modeling fluid-structure interaction for fuel impact and dispersion. The component and subassembly analyses were used to determine model simplifications for reducing the overall model size while maintaining fidelity in the global analyses.
• Initial conditions were estimated for the impact of the aircraft into the WTC towers. These included the aircraft speed at impact, aircraft orientation and trajectory, and impact location of the aircraft nose. The estimates also included the uncertainties associated with these parameters. This step utilized the videos and photographs that captured the impact event and subsequent damage to the exterior of the towers.
• Sensitivity analyses were conducted at the component and subassembly levels to assess the effect of uncertainties on the level of damage to the towers due to impact and to determine the most influential parameters that affect the damage estimates. The analyses were used to reduce the number of parameters that would be varied in the global impact simulations.
• Analyses of aircraft impact into WTC 1 and WTC 2 were conducted using the global tower and aircraft models. The analysis results included the estimation of the structural damage that degraded their strength and the condition and position of nonstructural contents such as partitions, workstations, aircraft fuel, and other debris that influenced the behavior of the subsequent fires in the towers. The global analyses included, for each tower, a “base case” based on reasonable initial estimates of all input parameters. They also provided a range of damage estimates based on variations of the most influential parameters. This range included more severe and less severe damage cases.
• Approximate analyses were conducted to provide guidance to the global finite element impact analyses. These included: (1) analysis of the overall aircraft impact forces and assessment of the relative importance of the airframe strength and weight distribution, (2) evaluation of the potential effects of the energy in the rotating engine components on the calculated engine impact response, (3) influence of the static preloads in the towers on the calculated impact damage and residual strength predictions, and (4) analysis of the load characteristics required to damage core columns compared to the potential loading from impact of aircraft components.

Pls provide the evidence.


The reports containing all the evidence can be downloaded free of charge at the above linked page.

Respectfully,
Myriad

[Heiwa]

From http://wtc.nist.gov/oct05NCSTAR1-2index.htm:

In order to estimate the aircraft impact damage to the WTC towers, the following steps were undertaken:

• Constitutive relationships were developed to describe the behavior and failure of the materials under the dynamic impact conditions of the aircraft. These materials included the various grades of steels used in the exterior walls, core columns, and floor trusses of the towers, weldment metal, bolts, reinforced concrete, aircraft materials, and nonstructural contents.
• Global impact models were developed for the towers and aircraft. The tower models included the primary structural components of the towers in the impact zone, including exterior walls, floor systems, core columns, and connections, along with nonstructural building contents. A refined finite element mesh was used for the areas in the path of the aircraft, and a coarser mesh was used elsewhere. The aircraft model included the aircraft engines, wings, fuselage, the empennage, and landing gear, as well as nonstructural components of the aircraft. The aircraft model also included a representation of the fuel, using the smooth particle hydrodynamics approach.
• Component and subassembly impact analyses were conducted to support the development of the global impact models. The primary objectives of these analyses were to (1) develop an understanding of the interactive failure phenomenon of the aircraft and tower components, and (2) develop the simulation techniques required for the global analysis of the aircraft impacts into the WTC towers, including variations in mesh density and numerical tools for modeling fluid-structure interaction for fuel impact and dispersion. The component and subassembly analyses were used to determine model simplifications for reducing the overall model size while maintaining fidelity in the global analyses.
• Initial conditions were estimated for the impact of the aircraft into the WTC towers. These included the aircraft speed at impact, aircraft orientation and trajectory, and impact location of the aircraft nose. The estimates also included the uncertainties associated with these parameters. This step utilized the videos and photographs that captured the impact event and subsequent damage to the exterior of the towers.
• Sensitivity analyses were conducted at the component and subassembly levels to assess the effect of uncertainties on the level of damage to the towers due to impact and to determine the most influential parameters that affect the damage estimates. The analyses were used to reduce the number of parameters that would be varied in the global impact simulations.
• Analyses of aircraft impact into WTC 1 and WTC 2 were conducted using the global tower and aircraft models. The analysis results included the estimation of the structural damage that degraded their strength and the condition and position of nonstructural contents such as partitions, workstations, aircraft fuel, and other debris that influenced the behavior of the subsequent fires in the towers. The global analyses included, for each tower, a “base case” based on reasonable initial estimates of all input parameters. They also provided a range of damage estimates based on variations of the most influential parameters. This range included more severe and less severe damage cases.
• Approximate analyses were conducted to provide guidance to the global finite element impact analyses. These included: (1) analysis of the overall aircraft impact forces and assessment of the relative importance of the airframe strength and weight distribution, (2) evaluation of the potential effects of the energy in the rotating engine components on the calculated engine impact response, (3) influence of the static preloads in the towers on the calculated impact damage and residual strength predictions, and (4) analysis of the load characteristics required to damage core columns compared to the potential loading from impact of aircraft components.




The reports containing all the evidence can be downloaded free of charge at the above linked page.

Respectfully,
Myriad

Yes, I am aware of these approximate simulations but I have not found any indications that, e.g. core column #501 - very strong to say the least - would have been damaged. It is fitted between two floors that would have sliced the plane as a cheese and then the column itself is very slender and would just deflect anything hitting it. 90 mm thick steel plates!
One problem is that none of the 280+ columns of the WTC1 initiation zone has been identified and analysed - damaged by plane or later 'buckled' (undefined) by heat in combination with very low compressive stresses (the mass above) and finally disappearing (how!) to allow the mass above to drop.

If you allege, as NIST, that the cause of the whole collapse is 'buckled' columns in the initiation zone, the least you need is one sample of such structural part.

[e^n]

Yes, I am aware of these approximate simulations but I have not found any indications that, e.g. core column #501 - very strong to say the least - would have been damaged.

If you allege, as NIST, that the cause of the whole collapse is 'buckled' columns in the initiation zone, the least you need is one sample of such structural part.

Your standard of evidence is tremendously biased. Such evidence can not reasonably be expected to exist, you are denying a plausible theory by demanding implausible amounts of evidence.

Have you found an error with NISTs simulation or have you performed a superior one which indicates column 501 would not be damaged? If not you are arguing from your personal disbelief which does not hold weight.

edit: I should add to make the above a bit clearer, when I say 'can not reasonably by expected to exist' I mean that the columns in WTC1 can be identified only by a small stamping on the steel, given the tremendous forces involved that day it is plausible that such columns could not be identified. It is important to realise how much evidence you should expect to be available to select a specific theory, whether this evidence is considerable enough to accept the theory as being correct is disputable, but you cannot claim that a lack of specific columns being recovered makes the NIST theory unprovable

[uk_dave]

NISTs theory is proved by what was witnessed on the day.

No one has managed to prove that this theory is impossible. Until they do so, there is no reason to believe that the towers could not have collapsed from the structural damage and fires alone.

[einsteen]

It is of course a combination of what can be seen/measured/estimated and what you have to assume in order to arrive at your end result. I've seen 100s of videos but not that the fireproofing was stripped. But if one can live with an incomplete explanation then that is fine.

[uk_dave]

It is of course a combination of what can be seen/measured/estimated and what you have to assume in order to arrive at your end result. I've seen 100s of videos but not that the fireproofing was stripped. But if one can live with an incomplete explanation then that is fine.


First, find out what spray on fireproofing is like. Is it hard or soft? Brittle or malleable?

Then consider the impact of a large object with the fireproof structure; an impact so great that large steel columns are visibly severed and debris from the impacting body is seen to burst out through the wall opposite the point of impact.

Then tell me the fireproofing had a better chance of being undamaged than damaged.

[Dave Rogers]

But if one can live with an incomplete explanation then that is fine.

The explanation's complete, it's the proof that has one or two thin spots. You must be thinking of somebody else's explanation.

Dave

[Dave Rogers]

Getting back, however briefly, to the original topic of this thread, I'd just like to comment on one paragraph of Gregory's paper.


It may be argued that the column damage contributed to weakness of the structure at collapse onset, but the collapse was clearly between floors 97-98 in WTC 1 and only three columns suffered light to moderate damage in the most severe case of impact simulation. Thus impact damage cannot be assumed to reduce the energy requirements for plastic deformation of the columns.


This clearly doesn't follow.

We know, of course, that significant numbers of exterior columns were severed at the point of initial impact. Gregory is arguing that, because the collapse onset was above this level, we still have to consider buckling of these columns at the region of collapse onset. However, the downward motion of the upper block can just as easily be accommodated by a downward displacement of the section of the column between the collapse initiation zone and the point of fracture of the column. The only structural elements restraining the columns from this downward motion are the spandrels and floor connections, which are therefore being loaded in shear and bending rather than compression.

Looking at the core columns, NIST's modelling predicts serious damage to a proportion of these also, and again the downward motion can be accommodated by downward displacement of the short section between the collapse zone and the point of failure. The only elements restraining the core columns are the floor connections, whose strength against shear is virtually negligible.

Finally, NIST's fire modelling predicts reduced yield strengths for core columns which at the time of collapse were significantly heated by fire, and again this permits a failure mode where the column is severed at the point of reduced strength, below the collapse initiation zone.

There is a certain amount of double counting to be eliminated here, because the failure of the columns due to heating was itself a cause of collapse initiation. However, I would argue that, for the reasons given above, the assumption that the structure in the region of collapse initiation was able to resist collapse with 98% of its undamaged strength is a significant overestimate, and that therefore the overload ratio is higher than the paper predicts.

Dave

[Norseman]

Yes, I am aware of these approximate simulations but I have not found any indications that, e.g. core column #501 - very strong to say the least - would have been damaged. It is fitted between two floors that would have sliced the plane as a cheese and then the column itself is very slender and would just deflect anything hitting it. 90 mm thick steel plates!
One problem is that none of the 280+ columns of the WTC1 initiation zone has been identified and analysed - damaged by plane or later 'buckled' (undefined) by heat in combination with very low compressive stresses (the mass above) and finally disappearing (how!) to allow the mass above to drop.

If you allege, as NIST, that the cause of the whole collapse is 'buckled' columns in the initiation zone, the least you need is one sample of such structural part.

These pictures of columns from the collapse initiation zone of WTC 1 have been posted by me earlier in this thread. I post them again in case you missed them.

http://forums.randi.org/imagehosting/thum_18141478e61f7f03e7.jpg
This is exterior column 210, a part of exterior panel A209 floor 97-100.

http://forums.randi.org/imagehosting/thum_1814147911cfef3c41.jpg
This is core column 605A floor 98-101

In addition to the columns above this is panel A130 floor 93-96 that was struck directly by the aircraft nose:
http://forums.randi.org/imagehosting/thum_18141479894a6d8c35.jpg
Here is a high resolution version showing the original identification labeling, so that you personally can identify the panel:
http://wtc.nist.gov/images/WTC-003_hires.jpg

All these columns are discussed in NIST NCSTAR 1-3B og 1-3C together with other columns and exterior panels from both towers. There are several pictures of severely buckled columns in these two reports. In addition I can show you numerous photographs of buckled columns in the debris pile after the collapse.

Do not try to move the goal posts after this Heiwa.

[GregoryUrich]

Getting back, however briefly, to the original topic of this thread, I'd just like to comment on one paragraph of Gregory's paper.



This clearly doesn't follow.

We know, of course, that significant numbers of exterior columns were severed at the point of initial impact. Gregory is arguing that, because the collapse onset was above this level, we still have to consider buckling of these columns at the region of collapse onset. However, the downward motion of the upper block can just as easily be accommodated by a downward displacement of the section of the column between the collapse initiation zone and the point of fracture of the column. The only structural elements restraining the columns from this downward motion are the spandrels and floor connections, which are therefore being loaded in shear and bending rather than compression.

Looking at the core columns, NIST's modelling predicts serious damage to a proportion of these also, and again the downward motion can be accommodated by downward displacement of the short section between the collapse zone and the point of failure. The only elements restraining the core columns are the floor connections, whose strength against shear is virtually negligible.

Finally, NIST's fire modelling predicts reduced yield strengths for core columns which at the time of collapse were significantly heated by fire, and again this permits a failure mode where the column is severed at the point of reduced strength, below the collapse initiation zone.

There is a certain amount of double counting to be eliminated here, because the failure of the columns due to heating was itself a cause of collapse initiation. However, I would argue that, for the reasons given above, the assumption that the structure in the region of collapse initiation was able to resist collapse with 98% of its undamaged strength is a significant overestimate, and that therefore the overload ratio is higher than the paper predicts.

Dave

I've been thinking a bit about this too. I agree that your points above are in line with a more realistic approach. The point about heating seems to be the main point of contention between the plane-fire-gravity (PFG) hypothesis and the plane-fire-CD-gravity (PFCDG) hypothesis. I think this question alone is worthy of a careful anaylsis of NIST's work because the conclusions are based on modeling rather than evidence.

Nonetheless, the strength at collapse initiation must be nearly mg because as soon as the strength falls below mg collapse will ensue. That would increase the overload ratio somewhat. However there are still other issues that may further reduce the ratio. More below.

I'm having trouble keeping the arguments within the Bazant and Zhou paradigm and making it more realistic without getting into a full blown collapse analysis. Keep in mind that the point of my paper is examining whether or not B&Z prove anything. My (hypo)thesis is that a more realistic analysis is necessary to prove the PFG hypothesis, NOT that the PFG hypothesis is incorrect.

The basic thesis of B&Z is that even with assumptions in favor of collapse arrest that the overload ratio is overwhelmingly in favor of collapse. Nonetheless they make many assumptions in favor of continued collapse. My approach has been to correct the assumptions in favor of continued collapse to make them neutral or slightly favoring arrest.

Thus to stay within the B&Z paradigm, I have corrected the collapse initiation level, but I have ignored damage below the collapse area. This is because B&Z have the upper part impacting an undamaged lower part. More realistically, the collapse initiation is on more than one floor and includes tilting: 97-98 on the north side, 96-97 on the south side, and the lower part is damaged.

There are more issues that involve the many assumptions. I will try to motivate each of the choices more carefully (similar to above) when I do a rewrite.

[Heiwa]

NISTs theory is proved by what was witnessed on the day.

No one has managed to prove that this theory is impossible. Until they do so, there is no reason to believe that the towers could not have collapsed from the structural damage and fires alone.

Not really! Nist states: "The release of potential energy due to downward movement of the building mass above the buckled columns (the cause) exceeded the strain energy that could be absorbed by the structure. Global collapse ensued (the effect) ."

No buckled columns below the building mass above have been identified or seen to 'buckle' at any time.

Downward movement of mass above cannot be correlated to 'buckled' columns below, e.g. the roof moves when all visible columns between floors 93-98 are not buckled.

Core column #501 cannot buckle under any circumstances. It is too strong. Same applies for a majority of other core columns.

The potential energy of mass above is not calculated by NIST.

The cause is not proven!

The strain energy of the structure is not calculated by NIST!

It is not shown that the potential energy exceeded the strain energy.

Regardless - it is not even shown that the potential energy of mass above was applied to the structure and that its strain energy is relevant.

Thus the effect (that we see) cannot be related to the proposed cause by NIST.

Conclusion - the effect, lack of strain energy and global collapse, could very well have been caused by something else. Don't ask me what.

[SDC]

Conclusion - the effect, global collapse, could very well have been caused by something else. Don't ask me what.

Cut by me to the last bit. H, don't weasel. You are obliged to say "what" you think it was. If you don't, even the wee tots at whom you claim your research is aimed will be entitled to holler "weasel" at you.

[Norseman]

Core column #501 cannot buckle under any circumstances. It is too strong. Same applies for a majority of other core columns.


In other words you are claiming that if all the other exterior and interior columns failed/were removed except #501, it should alone manage to keep the upper block standing.

[Dave Rogers]

Core column #501 cannot buckle under any circumstances. It is too strong. Same applies for a majority of other core columns.

Another Stundie nomination, from one of the true greats.

Dave

[stateofgrace]

Not really! Nist states: "The release of potential energy due to downward movement of the building mass above the buckled columns (the cause) exceeded the strain energy that could be absorbed by the structure. Global collapse ensued (the effect) ."

No buckled columns below the building mass above have been identified or seen to 'buckle' at any time.

Downward movement of mass above cannot be correlated to 'buckled' columns below, e.g. the roof moves when all visible columns between floors 93-98 are not buckled.


Am I missing something here?

Are you saying the perimeter columns did not buckle?

Core column #501 cannot buckle under any circumstances. It is too strong. Same applies for a majority of other core columns.
:dl:
Don't ask me what.Ok we won't .

[Heiwa]

These pictures of columns from the collapse initiation zone of WTC 1 have been posted by me earlier in this thread. I post them again in case you missed them.

http://forums.randi.org/imagehosting/thum_18141478e61f7f03e7.jpg
This is exterior column 210, a part of exterior panel A209 floor 97-100.

http://forums.randi.org/imagehosting/thum_1814147911cfef3c41.jpg
This is core column 605A floor 98-101

In addition to the columns above this is panel A130 floor 93-96 that was struck directly by the aircraft nose:
http://forums.randi.org/imagehosting/thum_18141479894a6d8c35.jpg
Here is a high resolution version showing the original identification labeling, so that you personally can identify the panel:
http://wtc.nist.gov/images/WTC-003_hires.jpg

All these columns are discussed in NIST NCSTAR 1-3B og 1-3C together with other columns and exterior panels from both towers. There are several pictures of severely buckled columns in these two reports. In addition I can show you numerous photographs of buckled columns in the debris pile after the collapse.

Do not try to move the goal posts after this Heiwa.

Evidently a column damaged before the collapse (by the nose of a plane) is of no interest. Nor is a 180° bent core column above the initiation zone of interest - the structure above is assumed to be intact all the time during the collapse until it probably is 'buckled' in contact with ground. Same with the crumpled up perimeter column - that should be a square box - that was part of the mass above.

In a proper forensic analysis you sort out all the parts, mainly columns, in the rubble and line them up on some football fields for further study. Not too difficult. By looking at the fracture surfaces of the columns, you can establish how they were ripped apart. Also the shape of each column after 'buckling' can be established. You do not even have to move the goal posts.

[Heiwa]

In other words you are claiming that if all the other exterior and interior columns failed/were removed except #501, it should alone manage to keep the upper block standing.

No, the same applies to all columns. #501 is just an example. I write for children. To keep it simple.

[Heiwa]

Cut by me to the last bit. H, don't weasel. You are obliged to say "what" you think it was. If you don't, even the wee tots at whom you claim your research is aimed will be entitled to holler "weasel" at you.

I have to disappoint you. I only claim NIST/Bazant are wrong in their analysises. Wrong cause! Buckling, potential energy, impacts!?!? Cannot produce the effect. That is easy to show using scientific methods. Too little energy. Gurich will show it in his rewritten paper.

So something else produced the effect. Using much more energy. But OT.

[DGM]

No, the same applies to all columns. #501 is just an example. I write for children. To keep it simple.
You write for children because they're the only ones that you can fool.

[SDC]

Another Stundie nomination, from one of the true greats.

Dave

I disagree. I don't think he can be ranked with the greats, yet. With Malcolm Kirkman, for example? Nah. He (Heiwa) has real potential, but he hasn't realized it yet.

Of course, he's got time. He doesn't appear to be someone who will either give up, or go out of control and commit suicide by mod.

I think he will rank more like... hmm, you're in the UK, I believe... Well, let me explain. US Baseball has its Hall of fame which elects retired players every year. And there are always controversies around this question: who is more worthy: the short-career spectacular? (Say, Don Mattingly). Or the long-career unspectacular who built up an impressive record by longevity and being consistently pretty good. (Say, Don Sutton, or Jack Morse.)

As things stand now, I predict that Heiwa will be of the latter variety; a Don Sutton among his kind. Always there, working hard, but never truly great.

Your views may differ. In this, I make no claims to certainty. Just my opinion.

[Norseman]

No, the same applies to all columns. #501 is just an example. I write for children. To keep it simple.
In other words, you claim that any column alone could have carried the upper block without failing, if all the other columns on a floor were removed. It is you who claimed that:

Core column #501 cannot buckle under any circumstances. It is too strong. Same applies for a majority of other core columns.

[e^n]

No, the same applies to all columns. #501 is just an example. I write for children. To keep it simple.

It may be true that every core column in the WTC was too slender to undergo euler buckling (Thanks Newtons Bit for helping my understanding) but they are certainly vunerable to inelastic buckling.

How much force must be applied to fail this column assuming the load distribution is not entirely uniform?

[Furcifer]

[snip]
So something else produced the effect. Using much more energy. [snip]

Yikes.

[StoneRook]

Not really! Nist states: "The release of potential energy due to downward movement of the building mass above the buckled columns (the cause) exceeded the strain energy that could be absorbed by the structure. Global collapse ensued (the effect) ."

No buckled columns below the building mass above have been identified or seen to 'buckle' at any time.

Downward movement of mass above cannot be correlated to 'buckled' columns below, e.g. the roof moves when all visible columns between floors 93-98 are not buckled.

Core column #501 cannot buckle under any circumstances. It is too strong. Same applies for a majority of other core columns.

The potential energy of mass above is not calculated by NIST.

The cause is not proven!

The strain energy of the structure is not calculated by NIST!

It is not shown that the potential energy exceeded the strain energy.

Regardless - it is not even shown that the potential energy of mass above was applied to the structure and that its strain energy is relevant.

Thus the effect (that we see) cannot be related to the proposed cause by NIST.

Conclusion - the effect, lack of strain energy and global collapse, could very well have been caused by something else. Don't ask me what.

Heiwa,

I've asked before, can you show your calculations for this?

Can you show how 501 cannot collapse under any circumstance?



You say NIST cannot prove it - can you prove what you say?

Again, please show your work here.

[Norseman]

Evidently a column damaged before the collapse (by the nose of a plane) is of no interest. Nor is a 180° bent core column above the initiation zone of interest - the structure above is assumed to be intact all the time during the collapse until it probably is 'buckled' in contact with ground. Same with the crumpled up perimeter column - that should be a square box - that was part of the mass above.

In a proper forensic analysis you sort out all the parts, mainly columns, in the rubble and line them up on some football fields for further study. Not too difficult. By looking at the fracture surfaces of the columns, you can establish how they were ripped apart. Also the shape of each column after 'buckling' can be established. You do not even have to move the goal posts.

You moved the goal posts big time, because you asked:
One problem is that none of the 280+ columns of the WTC1 initiation zone has been identified and analysed - damaged by plane or later 'buckled' (undefined) by heat in combination with very low compressive stresses (the mass above) and finally disappearing (how!) to allow the mass above to drop.

If you allege, as NIST, that the cause of the whole collapse is 'buckled' columns in the initiation zone, the least you need is one sample of such structural part.

And when I called your bluff, you then tried to explain it away by moving the goal posts.

And let me correct you on the perimeter column part, it was a part of the block blow. The crumbled up perimeter column looks very much like it was overloaded by the upper block during the collapse initiation. In fact the panel this column was a part of, A 209:97-100, covered floor 97 - 100. The collapse initiated on floor 98. The panel obviously broke in two parts, when the progressive collapse that initiated on the south side progressed to the position of this panel close to the north east corner of WTC 1 on the east side.

[Heiwa]

It may be true that every core column in the WTC was too slender to undergo euler buckling (Thanks Newtons Bit for helping my understanding) but they are certainly vunerable to inelastic buckling.

How much force must be applied to fail this column assuming the load distribution is not entirely uniform?

Buckling is always inelastic be it bending, twisting or crumpling up beyond yield stress. When it bucklebends the bending stresses are >yield, when it buckletwists the torsion stresses are >yield and when it bucklecrumples up it is the compressive stresses that are >yield. When a stress is >yield plastic deformation will start of different types and ruptures will occur if the stress >ultimate stress of the material. Otherwise it just deforms permanently. To stress a column you need a force. To deform it you need energy.

NIST fails to explain what type of buckling the 280+ columns in the initiation zone failed from. Due to low slenderness ratio of the core columns it should have been bucklecrumpling up ... but no such failed/deformed columns have been found.

Too little energy available for it, actually. Draw your own conclusions from that!

[uk_dave]

I thought it was the perimeter columns which failed......

...oh nevermind, it's not worth the effort

[Heiwa]

Heiwa,

I've asked before, can you show your calculations for this?

Can you show how 501 cannot collapse under any circumstance?



You say NIST cannot prove it - can you prove what you say?

Again, please show your work here.

You have to visit my website for it. As I am not allowed to link to it you can google with Anders Björkman + NIST. OK, the paper is written for children but maybe you will manage? 501 is a very solid column with slenderness ratio 10. To bucklebend it by compression is not possible as it will yield before it starts to bend. So only bucklecrumpleup is possible and for that you need a concentrated force of >2250 tons + a good support, which are not available anywhere. Anyway, NIST has given up the buckling idea and suggests now in its FAQ December 2007 that 6-11 floors in and above the initiation zone suddenly dropped down and caused the collapse. This is why you cannot see any perimeter columns bucklingcollapsing at all (Please note that a little bending is not equal to beckling). Evidently there is no evidence that any floors dropped down either. It is just an invention by NIST experts to support the myth that WTC1 collapsed by itself without any evil expeditious external energy input.

[uk_dave]

...... WTC1 collapsed by itself without any evil expeditious external energy input.

Ha!! My vote definitely goes to NIST.

Too funny.

[Apollo20]

Heiwa:

I am a little confused..... we all agree that WTC 1 & 2 collapsed, right, .... well that means that "floors dropped down", right, ... But you claim that "there is no evidence that any floors dropped down". So what are you saying?

And as for buckling, .... let's say there was very little buckling, and the main mode of core column failure was fracture at the weld planes. That was possible "without any evil expeditious external energy input" wouldn't you say?

[einsteen]

I've an other question Apollo20,

page 10 from http://www.nistreview.org/WTC-REPORT-GREENING.pdf

Prof Wierzbicki said that it takes 1.139*10^6 J to cut an exterior column,
then multiplying times 236+47*6.7 gives the often mentioned E1 value 0.63 GJ, Bazant independently derived 0.5 GJ from first principles.

In the paper we can read: Thus Wierzbicki considers floor support failure under lateral impact loading while Bažant’s considers the failure of the floor supports under axial impact loading. The fact that the energy calculated in each of these cases is about the same suggests that the energy dissipated in a floor collapse is relatively insensitive to the mode of failure of the support structures. This is a common observation in studies of collisions of large objects involving complex structures such as aircraft, automobiles, trains, and ships.

What I still don't understand is that the toppling of the block is crucial for a collapse that continues, I'm not really into columns and axial loads etc but does the above conclusion not really contradict that the toppling is relevant ?

And I don't know what Heiwa means with that single column, but it was no block standing on a single column but a large amount of columns, assume 80% is still intact then the 0.5GJ could be multiplied by 0.8, a huge amount of energy is needed.

The destroy is not directly possible form potential energy, first kinetic energy should be garthered. But in a slow movement there is not much kinetic or rotational energy. In 1d you can proof that it is absorbed, 3d is absolutely incredibly difficult but I still think it is amazing that your energy calculation (based on radial impact) is the same as a real crushing of the story and therefore the approach 3d -> 1d could be valid.

ps. and I don't know exactly where the fireproofing was dislodges, which core columns but that should give another factor. But the static load is still really a fraction of the maximum load

[Heiwa]

Heiwa:

I am a little confused..... we all agree that WTC 1 & 2 collapsed, right, .... well that means that "floors dropped down", right, ... But you claim that "there is no evidence that any floors dropped down". So what are you saying?

And as for buckling, .... let's say there was very little buckling, and the main mode of core column failure was fracture at the weld planes. That was possible "without any evil expeditious external energy input" wouldn't you say?

No - the floors dropped down first (cause) and the towers collapsed afterwards (effect). Why/how/when the floors dropped down (cause) is not known. Nist fantasy?

No - there is no such thing as very little buckling (unless you bump into someone's car at a supermarket parking with hysterical results). NIST has given up the official mass above 'buckled columns' idea and release of potential energy (cause) because the effect is ... no collapse.

Why would an assembly butt weld fracture in a lowly compressed column? What would cause that? Any details of this weld incl. location? It seems many welded connections failed ... but this was apparently long after collapse initiation; bolted floors suddenly falling down according NIST latest FAQ December 2007.

[Apollo20]

Einsteen/Heiwa:

I agree that collapse initiation is the key issue to be resolved in understanding the collapse. My energy transfer calculations were really only aimed at describing the energetics of the collapse itself using a simple model involving E1, "the energy needed to collapse one floor." I discussed the issue of how to calculate E1 in my paper because back when I wrote that paper I was struggling with ways to determine E1 and was happy to find any "guestimates" in the published literature. It was only later that I started to consider the tilting of the upper block as an important additional factor.

In the collapse initiation of WTC 2 we can clearly see the inward bowing of the east perimeter wall. I think this happened mainly because of the loss of horizontal bracing, as the trusses in the impact/fire-affected zone failed, than from the heating of the perimeter wall. Anyway, the bowing ultimately led to the east perimeter wall failure and allowed the upper block to tilt by tan^-1 (3.7/64) = 3.3 degrees - which is a lot! I think it was this downward movement that caused core columns to fail at their weakest point -the weld planes.

[StoneRook]

Heiwa - went to your site and must say....

"wow"

You compare the collapse to a child jumping on a bed?

You suggest building a model of the WTC out of plwood and some metal, and use a "water tank" to simulate the upper WTC block?

Then put a "pan of diesel oil on fire to simulate the jet fuel?

Ouch - even as a layman to structural engineering, I can see all kinds of wrong with your test....

I don't remember seeing a vast tank of water in the WTC that covered the entire floor(s).

I don't remember seeing it covered in plywood!

You don't model the trusses, the hat truss, the inner core and outer wall being pulled in by the sagging floor, you simply build four poles to hold up a water tank, surround it with plywood, fill that space with debris and a pan of diesel oil, and catch it on fire....

Can you really state is an accurate test?

You have read the NIST report, right?

[rwguinn]

Heiwa - went to your site and must say....

"wow"

<<snip>>
Can you really state is an accurate test?

You have read the NIST report, right?

sure he can--he states it all the time.
that doesn't make it true--see ad Nauseam (http://en.wikipedia.org/wiki/Ad_nauseam)

and item 2:
Nope. reading is for people who don't have enough imagination to make stuff up on the spot.

[pomeroo]

No, the same applies to all columns. #501 is just an example. I write for children. To keep it simple.


You write for children in order to communicate with an audience of your intellectual peers.

[Tony Szamboti]

Heiwa:

I am a little confused..... we all agree that WTC 1 & 2 collapsed, right, .... well that means that "floors dropped down", right, ... But you claim that "there is no evidence that any floors dropped down". So what are you saying?

And as for buckling, .... let's say there was very little buckling, and the main mode of core column failure was fracture at the weld planes. That was possible "without any evil expeditious external energy input" wouldn't you say?

Dr. Greening, you say above that you believe it was downward movement which caused the core columns to fail at their weakest point, which was the welds. I believe they were really only more susceptible in shear and bending. I am wondering if you could flesh out the mechanism that you believe might be able to account for the weld planes to fail at the initiation.

[beachnut]

I've an other question Apollo20,

page 10 from http://www.nistreview.org/WTC-REPORT-GREENING.pdf

Prof Wierzbicki said that it takes 1.139*10^6 J to cut an exterior column,
then multiplying times 236+47*6.7 gives the often mentioned E1 value 0.63 GJ, Bazant independently derived 0.5 GJ from first principles.

In the paper we can read: Thus Wierzbicki considers floor support failure under lateral impact loading while Bažant’s considers the failure of the floor supports under axial impact loading. The fact that the energy calculated in each of these cases is about the same suggests that the energy dissipated in a floor collapse is relatively insensitive to the mode of failure of the support structures. This is a common observation in studies of collisions of large objects involving complex structures such as aircraft, automobiles, trains, and ships.

What I still don't understand is that the toppling of the block is crucial for a collapse that continues, I'm not really into columns and axial loads etc but does the above conclusion not really contradict that the toppling is relevant ?

And I don't know what Heiwa means with that single column, but it was no block standing on a single column but a large amount of columns, assume 80% is still intact then the 0.5GJ could be multiplied by 0.8, a huge amount of energy is needed.

The destroy is not directly possible form potential energy, first kinetic energy should be garthered. But in a slow movement there is not much kinetic or rotational energy. In 1d you can proof that it is absorbed, 3d is absolutely incredibly difficult but I still think it is amazing that your energy calculation (based on radial impact) is the same as a real crushing of the story and therefore the approach 3d -> 1d could be valid.

ps. and I don't know exactly where the fireproofing was dislodges, which core columns but that should give another factor. But the static load is still really a fraction of the maximum load
Does this means each aircraft impact alone had enough energy, (huge amount of energy is needed) at 2.8GJ and 4.3GJ, to cut all the columns! More than once!?

And the tops falling had more than enough energy to destroy the floor below! Since a single floor can only hold itself and 10 or 11 floors, any thing over 6 floors falling any distance would make the floors below fail. These are the facts of the case and you can see the results in video recorded on 9/11. Debunking 9/11 truth is like cheating and having the answers already. Got some facts yet 9/11 truth?

You should weigh the floors and see how many it takes to fall or just land on a single floor before the floor fails, making the shell peel off, and the core unable to stand alone. Like you see on 9/11! A full scale model with no CD or thermite added like 9/11 truth lies about.

a slow movement there is not much kinetic or rotational energy WHAAAATTTT? Did you know moving only 1.85 meters, the WTC small top packs more than .5GJ. Oops, slow moving big mass is a lot of KE! U B Wrong. Hate to do the #s on the big top! Ouch. This means if it moves a distance of one floor, there is 1GJ! And the big top has a lot more falling just half a floor, would have a KE of 1.85! Small movement of big mass is a lot of energy, this is why a BIG slow train can not stop fast. This is why a slow ship hitting a big iceberg sinks!

[tsig]

Because release of potential energy of a mass above (cause) does not cause global collapse due to lack of strain energy of the structure below (effect) as alleged by NIST and Bazant (and Zhou).

The two are not related! First of all the potential energy must be applied to the structure below - there is no evidence for that.

NIST and Bazant assume the application of potential energy is an impact at high velocity on the structure below. No evidence for that.

If the application is at low velocity, which is the case, stresses in the structure below (and above!) are hardly affected and will evidently be same before and after loading.

It like hitting a nail (structure below) with a hammer (potential energy released). Too little speed nothing happens. To much speed nail bends and hammer slides off the nail and the energy is lost. It is not easy to hit a nail.

Bazant actually assumes that WTC1 is hammered 90 times; mass above (rigid and stiff all the time) first drops one floor that magically disappeared due to heat (the initiation zone) and crushes the floor below, i.e. deforms/buckles the supporting columns there and sweeps them out of the way (no evidence for that), then it drops another floor with same effect, then again ... 90 times. Evidently the rubble does not show any buckled columns, like that. Anywhere.

So Bazant's and Zhou's basic assumption is 100% wrong. Garbage in = garbage out.

NIST has abandoned the hammer/nail theory and suggests (FAQ Dec 2007) that 5-10 floors (in mass above) suddenly dropped down in the initiation zone (cause) and overloaded the first floor of the structure below (effect).

There is no evidence for that cause at all. It is pure fantasy. Note that NIST actually assumes that the mass above first disintegrates (before it was solid and stiff) and that now some subparts of the mass above (floors) suddenly drop down and do the hammering!

But again, there is no evidence that even one floor suddenly dropped!

In my article for children I just politely ask NIST and Bazant to re-do their analysises. No big deal! Very often mistakes are done in technical papers for various reasons.

Have you ever used a hammer?

[twinstead]

Heiwa don't you think it presumptuous that you ask NIST and Bazant to 're-do' their analysis? I'm sure their first response would be "just who the hell are YOU?"

What I mean is what if NIST and Bazant consider you to be somebody who has no idea what he is talking about questioning their conclusions?

Is there something you are expert on that you would consider some moron trying to tell you what he thinks about it irrelevant because he doesn't know what he is talking about?

What would your response be if Bazant or any of the EXPERT contributers to NIST said you didn't know what you were talking about?

[tsig]

I like Gurich's paper about overload caused by the mass above on the structure below.

The mass above is of course a hotch potch of structural items so it easiest just to look at one of them and apply the theory to it, e.g. core column #501

It is an H-beam with two flanges 17x3.5 inch connected by a 2.2x12.6 inch web.

In metric terms the flanges are 430x90 mm and the web is 56x320 mm. The cross area is about 950 cm², i.e. the column is very solid. It weighs 750 kgs/m. It may carry as much as 700 tons transmitted to it from the floors above, i.e. each floor above transmits about 50 tons to the column through bolted connections.

The compressive stress in this core column at floors 94-98 is then abt 736 kgs/cm² or 74 MPa or 30% of the yield stress of the steel. The (smallest) moment of inertia I of this section is about 120 000 cm4 and its radius of gyration is of the order 35 cms. With a free length of 350 cms the slenderness ration is 10! Removing three floors as support and the free length is 1 400 cms and the slenderness ratio is still only 40! The thick steel plates, 56 and 90 mm cannot buckle under any circumstance when the compressive stress is only 30% of yield stress even if the temperature is 500°C.

Anyway our humble experts at NIST suggest that a part of this column 'buckles' - probably it bends - in the initiation zone and then disappears (none has been found) so that the upper, top part - 700 tons - most of it floors bolted to it, drops down on the lower part - and hits it with an impact force!

NIST thus assumes that the upper part of one column hits the lower part of the same column without missing it. What happens then? I would assume that most bolted floor connections of the upper part shear off due to the impact.

And that should be the end of it. Hostile comments are always welcome as the houris await me in Paradise.

PS There are many photos of a woman standing waving on floor 93 of WTC 1 at the hole in the North wall. Not far behind her, inside WTC1 is core column #501.

The women died is that enough truth for you.

[Heiwa]

Heiwa - went to your site and must say....

"wow"

You compare the collapse to a child jumping on a bed?

You suggest building a model of the WTC out of plwood and some metal, and use a "water tank" to simulate the upper WTC block?

Then put a "pan of diesel oil on fire to simulate the jet fuel?

Ouch - even as a layman to structural engineering, I can see all kinds of wrong with your test....

I don't remember seeing a vast tank of water in the WTC that covered the entire floor(s).

I don't remember seeing it covered in plywood!

You don't model the trusses, the hat truss, the inner core and outer wall being pulled in by the sagging floor, you simply build four poles to hold up a water tank, surround it with plywood, fill that space with debris and a pan of diesel oil, and catch it on fire....

Can you really state is an accurate test?

You have read the NIST report, right?

I see that helpful henchmen of Nist are at it again and need some assistance to understand. The purpose of the model is only to see what happens to a steel column under 30% of yield compression when heated to 500°C, which apparently is a condition for later collapse. Nothing happens. And this is apparently one reason why Nist has abandoned that idea and now suggests that complete floors, 6 or 11, dropping down initiated the collapse.

But Nist fails to explain why floors dropped down at all. Somebody forgot to secure them? Somebody removed the bolts? These NIST FAQ December 2007 answers are really hilarious.

[Heiwa]

Heiwa don't you think it presumptuous that you ask NIST and Bazant to 're-do' their analysis? I'm sure their first response would be "just who the hell are YOU?"

What I mean is what if NIST and Bazant consider you to be somebody who has no idea what he is talking about questioning their conclusions?

Is there something you are expert on that you would consider some moron trying to tell you what he thinks about it irrelevant because he doesn't know what he is talking about?

What would your response be if Bazant or any of the EXPERT contributers to NIST said you didn't know what you were talking about?

Well, I was in fact corresponding with NIST about steel columns not crumpling up (buckling) at 500°C as contributing to collapse and NIST replied with a reference to floors dropping down instead + link to FAQ December 2007. Maybe they had read my CV?
If somebody told me I don't know what I am talking about, I am of course curious to know what technical aspect of the problem under discussion I have misunderstood. So we discuss collapse inititation. Crumpling columns are apparently not possible. Dropping floors? Frankly speaking, I cannot follow any logic there. Defective welding? I have no details but doubt it causes global collapse.
You need plenty of energy not only to initiate but also to complete global collapse of a structure and the potential energy available is too little.

[tsig]

Well, I was in fact corresponding with NIST about steel columns not crumpling up (buckling) at 500°C as contributing to collapse and NIST replied with a reference to floors dropping down instead + link to FAQ December 2007. Maybe they had read my CV?
If somebody told me I don't know what I am talking about, I am of course curious to know what technical aspect of the problem under discussion I have misunderstood. So we discuss collapse inititation. Crumpling columns are apparently not possible. Dropping floors? Frankly speaking, I cannot follow any logic there. Defective welding? I have no details but doubt it causes global collapse.
You need plenty of energy not only to initiate but also to complete global collapse of a structure and the potential energy available is too little.


Do you do English?

[twinstead]

Well, I was in fact corresponding with NIST about steel columns not crumpling up (buckling) at 500°C as contributing to collapse and NIST replied with a reference to floors dropping down instead + link to FAQ December 2007. Maybe they had read my CV?
If somebody told me I don't know what I am talking about, I am of course curious to know what technical aspect of the problem under discussion I have misunderstood. So we discuss collapse inititation. Crumpling columns are apparently not possible. Dropping floors? Frankly speaking, I cannot follow any logic there. Defective welding? I have no details but doubt it causes global collapse.
You need plenty of energy not only to initiate but also to complete global collapse of a structure and the potential energy available is too little.

You have been shown where you are wrong and/or where you don't know what you are talking about. Heck, since I'm not one to even try to understand much of this, I even showed this thread to a couple friends over at the engineering part of my local university and THEY said you don't know what you are talking about. Every person on this forum whom I suspect does know what he talking about says you don't know what you are talking about.

I mean no disrespect, of course, but this worries me. As a layman I need to rely on experts, and if all the experts who disagree with you are wrong, If the consensus of experts world wide is wrong, if the building code changes occurring world wide because of the NIST's findings are wrong, then there is something seriously wrong with the engineering community, and we are in grave danger walking into any large building anywhere.

Don't you agree?

[Norseman]

The mass above is of course a hotch potch of structural items so it easiest just to look at one of them and apply the theory to it, e.g. core column #501

It is an H-beam with two flanges 17x3.5 inch connected by a 2.2x12.6 inch web.

In metric terms the flanges are 430x90 mm and the web is 56x320 mm. The cross area is about 950 cm², i.e. the column is very solid. It weighs 750 kgs/m. It may carry as much as 700 tons transmitted to it from the floors above, i.e. each floor above transmits about 50 tons to the column through bolted connections.

The compressive stress in this core column at floors 94-98 is then abt 736 kgs/cm² or 74 MPa or 30% of the yield stress of the steel. The (smallest) moment of inertia I of this section is about 120 000 cm4 and its radius of gyration is of the order 35 cms. With a free length of 350 cms the slenderness ration is 10! Removing three floors as support and the free length is 1 400 cms and the slenderness ratio is still only 40! The thick steel plates, 56 and 90 mm cannot buckle under any circumstance when the compressive stress is only 30% of yield stress even if the temperature is 500°C.


Heiwa, are you aware of the fact that you picked the measurements for the section of column 501 that goes from floor 92 - 95. When I add in the extra floors using your 50 ton figure I find that this section was loaded to 40% of yield stress between floor 92 and 93. I get the same load factor for the two next column sections above.

I assume you found your measurements here:
http://wtcmodel.wikidot.com/cc501

I have not checked how you found that 50 ton figure, but maybe I should. And why this obsession with just 500 degree celsius, why not 600 or 700 degrees celsius. The later temperatures makes a dramatic difference.

[Major_Tom]

Apollo20 writes:

And as for buckling, .... let's say there was very little buckling, and the main mode of core column failure was fracture at the weld planes. That was possible "without any evil expeditious external energy input" wouldn't you say?

Same for the perimeter. Very little buckling observed in the rubble.

Very little buckling in the core, very little in the perimeter.

What do you have left?

No core box columns recovered from the collapse initiation zones.

38 foot giant rectangular things. Where did they go?

I am wondering if you could flesh out the mechanism that you believe might be able to account for the weld planes to fail at the initiation.

And don't forget about the lack of perimeter buckling seen in the rubble while explaining the progressive collapse mechanism.




The inability to provide buckled core columns from the collapse initiation regions shows that the Bazant theory of collapse initiation is not true.

You simply wish it to be true.

I found one of your damaged core box columns from the airplane strike. It has a dent in it's side but no buckle.



Norseman writes:

The crumbled up perimeter column looks very much like it was overloaded by the upper block during the collapse initiation.

This type of damage is the rare, rare exception.

You won't find many pieces like that among the debris, almost none.


Again, "faith" in buckling is all you have.

[Major_Tom]

Myriad writes:

Most of the columns were measurably bent, many of them to a degree that's easily visible even in photographs.

Of core columns this is simply untrue.

Of perimeter columns you will see bending but very little plastic buckling.


They could not match specific columns to specific as-built positions, for reasons they explained,

This is the center of the lie.

You point to debris which is so thoroughly mangled it is unrecognizable.

Please show me some core and perimeter columns that are so badly damaged they are on the verge of being unrecognizable.


The core columns in these regions were not recovered because they would ruin the power of the lie.


Judy Wood claims "dustification", and yet cannot show one partially "dustified" column.

Steven Jones claims "angle cuts" or "thermite cuts", yet cannot find more than a single angle-cut column (which is actually an oxy-lance cut).

You seem to claim that the evidence in this region was unrecognizable, yet you can't show core box columns that are partially unrecognizable.



So they are either totally destroyed or in remarkably good shape?

Your notion of the core "buckling" contains as much evidence as "dustification", and requires as much faith.



These lies have simply been repeated so many times that many people believe they are true.

[Myriad]

They could not match specific columns to specific as-built positions, for reasons they explained,


This is the center of the lie.

You point to debris which is so thoroughly mangled it is unrecognizable.

Please show me some core and perimeter columns that are so badly damaged they are on the verge of being unrecognizable.


Pardon me. I should have been more truthful, and said, "They could not match specific columns to specific as-built positions, for reasons they explained, but which since you haven't read their explanation, will be mysterious and suspicious to you."

Why don't you go read what those reasons actually are, and then we'll talk about this some more? I'll wait. (Hint: it has nothing to do with how "mangled" the columns were.)

Respectfully,
Myriad

[DGM]

Myriad writes:



Of core columns this is simply untrue.

Of perimeter columns you will bending but very little plastic buckling.




This is the center of the lie.

You point to debris which is so thoroughly mangled it is unrecognizable.

Please show me some core and perimeter columns that are so badly damaged they are on the verge of being unrecognizable.


The core columns in these regions were not recovered because they would ruin the power of the lie.


Judy Wood claims "dustification", and yet cannot show one partially "dustified" column.

Steven Jones claims "angle cuts" or "thermite cuts", yet cannot find more than a single angle-cut column (which is actually an oxy-lance cut).

You seem to claim that the evidence in this region was unrecognizable, yet you can't show core box columns that are partially unrecognizable.



So they are either totally destroyed or in remarkably good shape?

Your notion of the core "buckling" contains as much evidence as "dustification", and requires as much faith.



These lies have simply been repeated so many times that many people believe they are true.
You need a new hobby! Everything you have shown only supports what should have happened. Columns break at the weakest point, the weld. It's a shame you can't justify this in your mind.

[Major_Tom]

You need a new hobby! Everything you have shown only supports what should have happened. Columns break at the weakest point, the weld. It's a shame you can't justify this in your mind.

It escaped notice by your "experts" for many years.

Only now do you call it obvious.


What this actually shows is that nobody seemed to notice just how straight these columns really were until a "hobbyist" pointed it out.


Should have? Your experts missed it.


The Emperor has no clothes.

[DGM]

It escaped notice by your "experts" for many years.

Only now do you call it obvious.


What this actually shows is that nobody seemed to notice just how straight these columns really were until a "hobbyist" pointed it out.


Should have? Your experts missed it.


The Emperor has no clothes.
Why do you keep saying this? Most engineers are not in the habit of stating the obvious for the sake of the uninformed. You were not the first to notice this, you were the first to assume it was strange.

[Heiwa]

You have been shown where you are wrong and/or where you don't know what you are talking about. Heck, since I'm not one to even try to understand much of this, I even showed this thread to a couple friends over at the engineering part of my local university and THEY said you don't know what you are talking about. Every person on this forum whom I suspect does know what he talking about says you don't know what you are talking about.

I mean no disrespect, of course, but this worries me. As a layman I need to rely on experts, and if all the experts who disagree with you are wrong, If the consensus of experts world wide is wrong, if the building code changes occurring world wide because of the NIST's findings are wrong, then there is something seriously wrong with the engineering community, and we are in grave danger walking into any large building anywhere.

Don't you agree?

Details, please. What's wrong? We discuss what initiated the collapse and caused the alleged release of potential energy that later allegedly contributed to the global collapse. I show that the original structure was little stressed under compression (<30% yield) before inititation and that heat (500°C) will hardly affect it. But then I assume that something happens - buckling of all columns - and ask what kind of buckling; bending, twisting (torsion) or crumpling up (compression)? NIST ignores that.

And then there is the question if the 'buckling' resulted in release of potential energy (mass dropping down). It would appear that most energy is used only to 'buckle' the columns that deform a little ... and then should come to rest in a new state of equilibrium with deformed structural parts. This is what normally happens!

And NIST has apparently abandoned the complete column 'buckling' scenario and now suggests floors dropping down that initiated the global collapse.

But every video of the WTC1 collapse clearly shows that the roof drops considerably before anything serious happens at the initiation zone - where the floors are supposed to have dropped as the visible columns there are intact. After that all is hidden by smoke and dust.

Anyway, I also show that potential energy of a mass above cannot exceed the strain energy of the structure; another reason why global collapse will not ensue for the original NIST conclusion.

It is very disturbing that no pieces of the structure of the initiation zone are available for serious forensic examination to establish the initiation.

[Major_Tom]

Myriad notes:

"They could not match specific columns to specific as-built positions, for reasons they explained,

Is this from NIST 1-3c ?

I'm not seeing many reasons. Can you please indicate to what section and pages you are referring?


Why do you keep saying this? Most engineers are not in the habit of stating the obvious for the sake of the uninformed.

So NIST knew and didn't think it was important to mention? Bazant knew?

???


I couldn't be the first person to notice. You'd have to be blind not to notice.

[Major_Tom]

Einstein notes of samples of structural parts from the collapse initiation zones:

Such evidence can not reasonably be expected to exist,


??? Dustified?


Dave follows with:

Looking at the core columns, NIST's modelling predicts serious damage to a proportion of these also


If you are an investigative body, why theorize when you have access to the crime scene and the structural members being discussed?


Why are we "guessing" collapse initiation 6 years later when both core and perimeter sections contained all the information we needed?

[uk_dave]

So NIST knew and didn't think it was important to mention? Bazant knew?


What? That the core columns failed at their welds?

Maybe they should have produced a 'janet and john' version of their report.

Or, more in keeping with the 'truth' movement, produced 500 5 minute videos and posted them on youtube.

[Furcifer]

Why are we "guessing" collapse initiation 6 years later when both core and perimeter sections contained all the information we needed?


That's a bold statement after the fact. I find it fascinating that the truth movement puts their faith in the notion that the evidence of conspiracy could easily be found in information that cannot possibly be obtained. It's always about theorizing about what's not there, instead of focussing on what is there. No offence, but a statement such as the one above clearly shows you will never be satisfied Major Tom. No matter how much you are shown and explained you will always fall back on this arguement because in your eyes it's so simple. It's a symptom of woo many on this forum have seen over and over.

To answer your question, we are guessing collapse initiation because it is an impossible question to answer with the given information unless you are willing to accept the fact that it was caused by the impact of two jets hijacked by terrorists and flown into the buildings.

[bje]

I find it fascinating that the truth movement puts their faith in the notion that the evidence of conspiracy could easily be found in information that cannot possibly be obtained.



It's the nature of the beast. Remember the Truther's main premise: "If there's neither a photo nor video of an event, it didn't happen." Thus, because there's no video nor a photo of the Titanic sinking AA77 hitting the Pentagon, it didn't happen.

[GregoryUrich]

Einstein notes of samples of structural parts from the collapse initiation zones:




??? Dustified?


Dave follows with:

Looking at the core columns, NIST's modelling predicts serious damage to a proportion of these also


If you are an investigative body, why theorize when you have access to the crime scene and the structural members being discussed?


Why are we "guessing" collapse initiation 6 years later when both core and perimeter sections contained all the information we needed?

Ok, we have an issue here regarding failure mode. I would like to start a new thread to focus on this issue. My proposal for the OT:

Failure mode in WTC towers

Major Tom has, after a review of 100s and 100s of photos, pointed out that columns (both external annd internal) showing member failure (rupture or buckling) represent a very small minority compared to columns failing at their connections (i.e. welds amd bolts). If there was consensus on this issue it would greatly help further the discussion.

I think it would be useful to split the discussion between collapse initiation and the rest of the collapse. Collapse initiation involved less than 3% of the total number of column members (i.e 3 story, whole pieces of steel or external panels with which the vertical supporting structure was assembled during construction). The rest of the collapse involves the other (more than 97%) column members.

For the 97% question:

If member buckling is an important failure mode then I suggest at least half of the photos should show this. We have seen a number of buckled columns but they are still seem to be a very small minority. If the available photos cover only 10% of the members, we should be able to find 75 different buckled core columns and at least 200 buckled external panels.

Personally I have looked at 100s and 100s of photos, essentially randomly on many different sites and in Joel Myerowitz's book. I haven't seen very many examples of member failure either. Is this really an issue? Or are we just not understanding one another?

My suggestion is that, if there are people opposing this conclusion, to do an honest random sample of 50-100 photos and report back with numbers and sources. We will need to agree on what member failure as opposed to connection failure looks like. Any ideas?

[Myriad]

Is this from NIST 1-3c ?

I'm not seeing many reasons. Can you please indicate to what section and pages you are referring?


You mean, you've accused NIST of lying about the steel identification process ("This is the center of the lie") without having examined the relevant documentation of their work? Or even being aware of its existence?

Chapter 3 (which is the main body) of http://wtc.nist.gov/NISTNCSTAR1-3B.pdf]NCSTAR 1-3B describes, item by item, what evidence was available to determine the as-built position of each piece of the recovered steel.

However, rather than skip directly to chapter 3, please read the document from the beginning, so you won't need me to answer your inevitable next question, "why was so little of the steel recovered?"

By the way, you might also notice a few images of buckled, non-straight, core column steel in that document, if you look very carefully. (That is, carefully enough not to miss the large color photographs on pages 6, 40, 41, 42, 43, 44, 45, 77, 78, and 79.)

Respectfully,
Myriad

[Norseman]

Norseman writes:
The crumbled up perimeter column looks very much like it was overloaded by the upper block during the collapse initiation.
This type of damage is the rare, rare exception.

You won't find many pieces like that among the debris, almost none.


Yes, of course it is rare since it came from the floor where the collapse initiated in WTC 1. It was weakened by fire, it became overloaded when the progressive collapse that broke off all the columns on floor 98th reached its position close to the north east corner. It was this collapse that allowed the upper block to fall down inside the lower block and completely destroy the whole tower. We should not expect to see this type of damage in the other perimeter columns, because they peeled of the tower when the upper block went down inside the lower block and disconnected the interior floors from the columns. When the exterior walls peeled off they broke up in smaller sections. As expected they failed in the bolt connections when they broke up. If you take your time to study NIST NCSTAR 1-3C you will find that NIST is very well aware of the fact that the exterior columns failed in their bolt connections.

[Major_Tom]

Gregory writes:

My suggestion is that, if there are people opposing this conclusion, to do an honest random sample of 50-100 photos and report back with numbers and sources. We will need to agree on what member failure as opposed to connection failure looks like. Any ideas?

I agree. But this requires effort on the part of the observer.

This is always the stumbling-block: Effort and honesty.

I am sorry for posting things in this thread which seem to deviate from the direction you wish to see, Gregory. I didn't have the time to start another thread properly and the questions were related to the Bazant paper.

This is what I suggest for anyone that wants to know: Start a separate photo collection for all the core box columns you see that are not...

1) Remarkably straight

2) Separated from from the others cleanly along their original weld surfaces. (Just look at their ends.)


You will find that the photo album is not that big at all.

You will notice that you have to look past many, many very straight columns with squared-off ends just to find one or two.




It is within this context that the inability to study the actual initiation failure mode by collecting representative columns samples from those areas is shown to be nonsense.

4 core samples collected?

You folks have a deep-seated faith.

I've been surprised to discover how little you actually have by way of evidence.


I believed you had more.


Your defense of such a scant collection of core columns tells the honest reader that you have nothing but a belief system:


Buildings fell, therefore core columns buckled.

[Major_Tom]

Norseman writes:

It was this collapse that allowed the upper block to fall down inside the lower block and completely destroy the whole tower. We should not expect to see this type of damage in the other perimeter columns, because they peeled of the tower when the upper block went down inside the lower block

Thanks for giving some kind of failure scenario. Notice how nobody else is repeating this scenario. Your scenario, or floor failure, are about the only possibilities left for people who believe in the OT, considering the general conditions of both core and perimeter columns seen in the rubble.

Considering that mechanical room perimeter columns just below the failure initiation point on WTC 2, east face, were seen unbuckled, speared into the ground and had flew clear over WTC 4, you scenario is at least an attempt to explain what was observed.


3bodyproblem notes in fascination:

I find it fascinating that the truth movement puts their faith in the notion that the evidence of conspiracy could easily be found in information that cannot possibly be obtained.

This info couldn't possibly have been obtained?


???

[Newtons Bit]

Major Tom, the reasons why the columns failed in buckling but no large deformities are present in the columns is based on simple engineering principles.

http://forums.randi.org/imagehosting/thum_16329479baa90cc44e.jpg (http://forums.randi.org/vbimghost.php?do=displayimg&imgid=10396)

Just do the math. Figure out what bending moments are on the column splice when the column is still elastic. When you figure that out, you'll know why.

[GregoryUrich]

Gregory writes:



I agree. But this requires effort on the part of the observer.

This is always the stumbling-block: Effort and honesty.

I am sorry for posting things in this thread which seem to deviate from the direction you wish to see, Gregory. I didn't have the time to start another thread properly and the questions were related to the Bazant paper.

This is what I suggest for anyone that wants to know: Start a separate photo collection for all the core box columns you see that are not...

1) Remarkably straight

2) Separated from from the others cleanly along their original weld surfaces. (Just look at their ends.)


You will find that the photo album is not that big at all.

You will notice that you have to look past many, many very straight columns with squared-off ends just to find one or two.




It is within this context that the inability to study the actual initiation failure mode by collecting representative columns samples from those areas is shown to be nonsense.

4 core samples collected?

You folks have a deep-seated faith.

I've been surprised to discover how little you actually have by way of evidence.


I believed you had more.


Your defense of such a scant collection of core columns tells the honest reader that you have nothing but a belief system:


Buildings fell, therefore core columns buckled.

No problem. I just think a new thread would help focus on the failure mode which is an important issue in itself. I can start it and see if anyone follows.

[Norseman]

No core box columns recovered from the collapse initiation zones.

38 foot giant rectangular things. Where did they go?


There were no box columns in the collapse initiation zone of WTC 1 on floor 98. All were rolled wide flange columns.

In the initiation zone of WTC 2 on floor 81/82 there was only 17 box column out of 47. And they were square and nothing like the size of the big square ones lower in the tower.

See Figure 2-6 in NIST NCSTAR 1-3 for floor of transition from box column to rolled wide flange column.

This column was recovered from the collapse initiation zone of WTC 2:
http://forums.randi.org/imagehosting/18141479bb34421c8c.jpg

See NIST NCSTAR 1-3B and 1-3C for further details.

But I guess that you are going to deny that this one is genuine to since it was photographed in a parking lot and not in the debris pile.

How do you think it failed?

[Major_Tom]

Thanks for showing some model, NB.


We'll look into this to see if this matches what was observed.



Gregory, good idea.

[SDC]

Major Tom, the reasons why the columns failed in buckling but no large deformities are present in the columns is based on simple engineering principles.

http://forums.randi.org/imagehosting/thum_16329479baa90cc44e.jpg (http://forums.randi.org/vbimghost.php?do=displayimg&imgid=10396)

Just do the math. Figure out what bending moments are on the column splice when the column is still elastic. When you figure that out, you'll know why.

NB, you must have noticed that MT doesn't do math. He looks at pictures. Not a bad practice in and of itself, but no substitute for serious work.

This thread is just insane. Heiwa and MT and all... they are clueless. They will probably spend the rest of their lives maintaining their unsupportable positions, regardless of common sense, observation, and the work of actual engineers. What madness.

[Major_Tom]

Norseman, thanks for the photo. Strong weld, no?


.

[Norseman]

Norseman, thanks for the photo. Strong weld, no?


Or could it be that the upper portion of that column was weakened by heat due to fire. And that it still had support from the channel that connected it to the floor trusses on floor 81. So when the upper block started to tilt, when the columns on the east side of that floor failed, it therefore buckled above floor 81 when it became overloaded, and broke off from the upper block like all the columns on that level, allowing the upper block of WTC 2 to fall down inside the lower block, where it ripped off the floor connections on its way down.

Therefore this column is expected to look differently than majority of the column sections in the collapse that broke at their bolt connections or weld connections as expected. But that would not prevent those columns from being bent in the collapse before their connections broke. Or after.

[GregoryUrich]

Major Tom, the reasons why the columns failed in buckling but no large deformities are present in the columns is based on simple engineering principles.

http://forums.randi.org/imagehosting/thum_16329479baa90cc44e.jpg (http://forums.randi.org/vbimghost.php?do=displayimg&imgid=10396)

Just do the math. Figure out what bending moments are on the column splice when the column is still elastic. When you figure that out, you'll know why.

Not to make things complicated, but shouldn't the three horizontal members be able to handle some magnitude of eccentricity. Granted the towers had severe eccentricity due to tilting. Not really proper usage of term "eccentricity" but I think you'll get my drift.

[beachnut]

I have recalculated Bazant and Zhou's overload ratio with the result that progressive collapse is not predicted by the model. Please see the article:

http://www.cool-places.0catch.com/docs/Overload.pdf

Any constructive comments would be appreciated.
If you provide a model that proves the WTC can not fail due to impact and fire; you will be wrong again. And I think this paper has some real stupid statements in it. But when you get to your own paper, it will be a failure like the rest of 9/11 truth. 6 years and not a single correct conclusion.
http://www.beachymon.com/photo/failure.jpg
Since the WTC did fail due to impact and fire, you have failed in advance.

[Newtons Bit]

Not to make things complicated, but shouldn't the three horizontal members be able to handle some magnitude of eccentricity. Granted the towers had severe eccentricity due to tilting. Not really proper usage of term "eccentricity" but I think you'll get my drift.

Draw a moment and shear diagram of the column. Then do it again with the diaphragm disconnected.

I didn't draw that picture to scale, however. Column splices are typically 4feet above finished floor to make it easier on the labor to construct.

[Heiwa]

Subject is collapse initiation and WTC1 is easiest to study, i.e. we can see on all videos how the roof drops for 4-5 seconds and there is still no damage at floor 93. In fact it appears that the top part of WTC1 above the initiation zone becomes 15 meters shorter while structure below floor 93 is still intact. And no structure above floor 93 is seen being pushed outwards.

So how can the top part lose 15 meters of its height in a few seconds? Did the walls bucklebend 180° inwards? Where did the floors end up. And what happened to the core? Did it bucklebend 180° utwards still inside the building?

The answers are evidently found by studying the remnants of columns from floor 93-101 of WTC1.

[Furcifer]

3bodyproblem notes in fascination:
This info couldn't possibly have been obtained?
???

You changed tenses and therein lies the problem. Perhaps it could have. Perhaps, in a mountain of rubble, the exact pieces you so desire could have been extracted. But they weren't.

Veiled in your question of "How?" is "Why?", and i see no answer to your "How" that will ever change the answer to your actual question of "Why?". Perhaps I'm being too cryptic, I'm not sure.

Anyways, my apologies to Greg and yourself as this is off topic. I mean no disrespect as this is an intelligent conversation and I encourage it to continue.

As to your question (one of them), the welds look nonexistent in the photos. It's interesting and I'll have to learn more.

[Major_Tom]

3bodyproblem and all, I believe we are moving that ongoing conversation within this thread to a new thread entitled "failure mode" at Gregory's request.

I'll be moving my part of this exchange over there.

No offence taken. I appreciate the honest discourse.

[Heiwa]

If you provide a model that proves the WTC can not fail due to impact and fire; you will be wrong again.

Let's do a model test!

You need:

4 off steel pipes, length 750 mm, dia 20 mm wall thickness 1 mm (each cross area 62.83 mm²). Yield stress 23.5 kgs/mm²
1 off 1000 x 1000 x 5 mm steel plate (weight about 40 kgs)
4 off 1000 x 1500 x 5 mm steel plates (each weight about 60 kgs)
4 off 960 x 4 x 3 mm steel flat bars (spandrels)
4 off plywood sheets 995 x 920 x 5 mm. Make some holes in them to allow air to enter and smoke to escape! One hole can look like as if a model air plane has made it.

You weld the pipes to the corners of the square steel plate and you get a table with four legs. Each leg has slenderness ratio abt. 75. Weld the spandrels between the legs at about half height.
Put table on firm ground, e.g. cement floor.
Then weld the four other plates on the top of this table to form a 'water tank'.
Fix the four plywood sheets between the legs of the table as a skirt.

Decorations: The 'water tank' on the table is the 'upper mass' of WTC1. You can paint it to look like it. The four plywood sheets - the skirt - are the walls of the initiation zone of WTC1. You can paint that too to look like it. It is in fact a 1/20 model of part of WTC1 'mass above' and 'initiation zone'. The legs are four of the columns!

Load on table: In order to compress the table legs in the WTC1 model initiation zone at say 30% yield we need abt 1 500 kgs of weight on the table top! Thus you fill the water tank to level about 1.5 meter and there you are: 1 500 kgs of water + 280 kgs of steel plates = 1 780 kgs are carried by four legs each cross area 63 mm². Stress in columns = 7.06 kgs/mm² = 30% of yield stress.

Table, 0.755, m and tank, 1.5 m, make a 2.255 m high model of WTC1 mass above and initiation zone!

Then you fit a suitable thermometer to record the temperature inside the initiation zone.

The volume of the initiation zone is only 0.75 m3 and it is quite easy to heat it up to 500°C!

Cost of model is not too much: 7 m² of 5 mm steel plate (280 kgs) - say $400:- Pipes $20:-, Skirt $80:- welding rods, paint and misc. $100:- . Labour $ 0:-, if you ask daddy to assemble it.

Now the fun starts! We are going to put this model of WTC1 on fire! Or at least the initiation zone.

Put a tray of one gallon diesel oil on the cement floor between the legs of the model and fill the rest of the initiation zone with paper, rugs and similar.
Now put the diesel oil on fire! See how the initiation zone heats up, air is drawn in and smoke escapes through the holes. Very soon the temperature is 500°C uniformly inside the initiation zone and the table legs are heated up to same temperature. The plywood will burn very slowly.

The purpose of the model test is of course to establish the stiffness of the table leg pipes (the columns of the initiation zone) under heat and to see if suddenly, at, e.g. temperature 500° C, the mass above (luckily most water in this test) drops down, at a significant speed and with an enormous kinetic energy, and impacts on the cement floor with an enormous dynamic load.

Or does nothing of that sort happen? Maybe the table legs will just bulge. You will find out (the latter)!

[westprog]

the potential energy available is too little.

Have you done the potential energy calculation?

[Heiwa]

Have you done the potential energy calculation?

Of course. That is the first I did (of course only two months ago when I first seriously studied the matter) ... and which NIST didn't do ... ever. See my paper! The top of WTC1 is 95% air! On top of a lightly compressed structure below. Nothing can happen. It seems the Washington Lyers henchmen were out on the streets of NY 911 and in the media 911 and told otherwise = pure propaganda (check them out - http://www.sott.net/articles/show/146563-The-9-11-Solution-RESTORED-The-Video-Google-Censored ). Small Town Truthers have then difficulties to get their message through.

FCC rules? It seems ABC was fined $1.4 million yesterday to have shown a nude bottom (arse) of a female police between 18 and 22 hrs pm last Friday and that any Small Town Truthers news can only be shown between 03.59 and 04.00 hrs am any local US time, so I understand the latter has problems to get their message out. It is very simple! Buildings built with steel columns as supporting structure never collapses completely due to a local fire high up on some top storeys. It is a fact. The opposite is propaganda.

Do my simple model test and convince yourself.

[pomeroo]

Of course. That is the first I did (of course only two months ago when I first seriously studied the matter) ... and which NIST didn't do ... ever. See my paper! The top of WTC1 is 95% air! On top of a lightly compressed structure below. Nothing can happen. It seems the Washington Lyers henchmen were out on the streets of NY 911 and in the media 911 and told otherwise = pure propaganda (check them out - http://www.sott.net/articles/show/146563-The-9-11-Solution-RESTORED-The-Video-Google-Censored ). Small Town Truthers have then difficulties to get their message through.

FCC rules? It seems ABC was fined $1.4 million yesterday to have shown a nude bottom (arse) of a female police between 18 and 22 hrs pm last Friday and that any Small Town Truthers news can only be shown between 03.59 and 04.00 hrs am any local US time, so I understand the latter has problems to get their message out. It is very simple! Buildings built with steel columns as supporting structure never collapses completely due to a local fire high up on some top storeys. It is a fact. The opposite is propaganda.

Do my simple model test and convince yourself.


How do steel buildings fare when fully-fueled commercial airliners slam into them at high speeds? To date, the only two examples we have collapsed. Why are you talking about buildings with small local fires and pretending it has relevance to the jihadist attacks of 9/11/01. You should stop peddling propaganda and learn something about physics. The real scientists and engineers here have made you look ridiculous.

[DGM]

How do steel buildings fare when fully-fueled commercial airliners slam into them at high speeds? To date, the only two examples we have collapsed. Why are you talking about buildings with small local fires and pretending it has relevance to the jihadist attacks of 9/11/01. You should stop peddling propaganda and learn something about physics. The real scientists and engineers here have made you look ridiculous.
Actually Ron no one here had to make him look ridiculous.

[StoneRook]

95% air???

Where do you come up with these figures?

I've talked to two engineers I know, and showed them your "paper" and your "model"..

They said it is completely off...

To wit, they suggested if you wanted to model the WTC, you actually have to make a model that has some connection to the real thing....

Which your "model' doesn't do.

The also warned me not to go into any structure/ship you may have had any hand in constructing....

Good advice I think....

Thanks for the "henceman" comment, just goes to show when you hit someone on the head with reality, they have to flail about and claim people are "in on it",

whatever makes you sleep at night I suppose...

[Heiwa]

95% air???

Where do you come up with these figures?

I've talked to two engineers I know, and showed them your "paper" and your "model"..

They said it is completely off...

To wit, they suggested if you wanted to model the WTC, you actually have to make a model that has some connection to the real thing....

Which your "model' doesn't do.

The also warned me not to go into any structure/ship you may have had any hand in constructing....

Good advice I think....

Thanks for the "henceman" comment, just goes to show when you hit someone on the head with reality, they have to flail about and claim people are "in on it",

whatever makes you sleep at night I suppose...

Evidently the top of WTC1 is 95% air volume wise. Then you have 4% concrete, glass, furniture, cabling, etc and 1% steel structure. Like most skyscrapers. And you can slam an airplane into it and destroy part of the steel structure and nothing happens due to structural redundancy. The tower was built very strong! Very low stresses in the structure.

The steel structure takes very little space so an aluminium/plastic plane cannot destroy many steel parts. Most fuel in the plane burns very quickly in a ball of fire and then a normal office fire starts. No big deal. Cannot harm the steel structure. It is like a fire in an iron stove. The stove does not melt, buckle or collapse. If you believe otherwise, you have been fooled.

But let's assume all the steel columns buckle in way of the impact/fire zone. The only result would be that the columns bend and crumple and that the top part of the tower above (95% air) moves down a little. The buckled columns will act as fenders and prevent damage of the tower below. If you believe otherwise, you have been fooled, I have to repeat.

My model will however demonstrate that the columns will not buckle due to the fire.

I have designed and built many steel ships with very good results so you do not have to worry about that. Sleep well.

[Furcifer]

The steel structure takes very little space so an aluminium/plastic plane cannot destroy many steel parts. Most fuel in the plane burns very quickly in a ball of fire and then a normal office fire starts. No big deal. Cannot harm the steel structure. It is like a fire in an iron stove. The stove does not melt, buckle or collapse. If you believe otherwise, you have been fooled.



Except for the fire ball part, this paragraph is completely backwards. It was a big steel strucutre, with many destroyed steel parts, the fire was a big deal, it did harm the steel strucutre, stoves have deformed from too much heat (good oak and a strong wind) and you have been fooled if you believe otherwise.

[DGM]

Except for the fire ball part, this paragraph is completely backwards. It was a big steel strucutre, with many destroyed steel parts, the fire was a big deal, it did harm the steel strucutre, stoves have deformed from too much heat (good oak and a strong wind) and you have been fooled if you believe otherwise.
The 95% part has to do with if it was a solid object. I suspect he mentions this to fool the children that he hopes to convince. You know to sound smart to the uninformed. Why he says it here is beyond me.

[Furcifer]

The 95% part has to do with if it was a solid object. I suspect he mentions this to fool the children that he hopes to convince. You know to sound smart to the uninformed. Why he says it here is beyond me.


too bad the planes missed the 95% and only hit the other 5%.

[bje]

I have designed and built many steel ships with very good results so you do not have to worry about that. Sleep well.


You mean your ships sank faster than free fall?

[Heiwa]

Except for the fire ball part, this paragraph is completely backwards. It was a big steel strucutre, with many destroyed steel parts, the fire was a big deal, it did harm the steel strucutre, stoves have deformed from too much heat (good oak and a strong wind) and you have been fooled if you believe otherwise.

According NIST the WTC1 impact cut 65% of the vertical columns of one wall while the other three walls were 100% intact. Looking through the hole we see some local damage to three floors, that must have sliced the plane horizontally. These floors were originally hanging on the wall and core columns and are not sagging, i.e. were held in place by the core columns after impact.

A fair distance from the hole is the core with fewer, stronger and wider spaced columns and there is no evidence that even the core columns closest to the hole were damaged as the floors were still in place (apart from some little floor damages just inside the hole). And the tower was still standing = plenty of redundancy. In my opinion 92% of the supporting columns were intact = a small damage. The resultant office fire (mainly furniture) only heated some local steel structure max 500°C and then no serious deformation of steel structure can take place. It was not a closed stove - more an open fire place, BBQ style, you know. The steel equipment you use to grill beefsteaks do not melt or buckle but I agree. It is quite hot just above the burning coal.

I fully agree with NYFD that they could have handled the fires, i.e. contain them, stop them from spreading or let them burn out. No panic! I have actually been trained to do such jobs.

The sudden falling down of the roof 15 meters not associated with any visible damage to the walls at the hole, i.e. the top part telescoping (sliding down into the tower below), is not correctly explained by NIST. It takes place 5 seconds prior to the tower below collapsing. It cannot be the result of columns buckling below the top part as they are seen intact and could never be damaged by the available heat. Do my model test and convince yourself!

The NIST cause "The release of potential energy due to downward movement of the building mass above the buckled columns exceeded the strain energy that could be absorbed by the structure" is therefore wrong. No columns buckled in the fire zone. Why invent that? And of course NIST never shows in its 10 000 pages report that the potential energy released did exceed the strain energy that could be absorbed by the structure. It is just a nonsense statement by civil servants to please their Masters and not to be harrassed by their henchmen and other hoodlums.

It is not easy to be a civil servant with such Masters.

[Furcifer]

According NIST the WTC1 impact cut 65% of the vertical columns of one wall while the other three walls were 100% intact.


It's been a while since I last perused NCSTAR, but if the above statement is correct (all of it) there's a glaring omission as to damage on the exterior columns on the exit side. Can you please provide direct reference to this, or is this merely your own deduction?



Looking through the hole we see some local damage to three floors, that must have sliced the plane horizontally. These floors were originally hanging on the wall and core columns and are not sagging, i.e. were held in place by the core columns after impact.

I'm not exactly sure what you are saying here but I'd guess it to be as follows: "The floors as seen through the hole in the facade appear to be held in place by connection to the core alone as there is no observed sagging" Without getting into whether or not the floors sagged in the impact area prior to collapse, I'm curious what your answer to the following question would be:
Wouldn't the moment arm created by the now detached floor trusses place a much greater torsional force on the core columns at their connections? Thus remaining attached to the core columns caused more damage (this torsional force applied over time) than if they had merely snapped off at initial impact?

[bje]

I fully agree with NYFD that they could have handled the fires, i.e. contain them, stop them from spreading or let them burn out.


NONE of the firefighters of NYFD said any such thing, Heiwa. Why do you lie about it?

[Heiwa]

I'm curious what your answer to the following question would be:
Wouldn't the moment arm created by the now detached floor trusses place a much greater torsional force on the core columns at their connections? Thus remaining attached to the core columns caused more damage (this torsional force applied over time) than if they had merely snapped off at initial impact?

Evidently the floor truss bolted connection to all columns transmits a shear force that compresses the column and a bending moment that bends the column. But looking at the actual connection of the truss to the column the bending moment must be very small - the max bending of the truss is therefore at its mid-length. When one support - at the wall column - is removed, you would expect the truss to sag but it is also held by the thin plate connecting all trusses (and the cement on top) and the weights are small (500 kgs/m²) so the sag is also small.

[einsteen]

too bad the planes missed the 95% and only hit the other 5%.
It's nice to make a joke about it but that was what actually happened. If all kinetic energy of the plane would be available to cut the columns (if we believe the values to cut them) then the block would fall immediately.

[Furcifer]

It's nice to make a joke about it but that was what actually happened. If all kinetic energy of the plane would be available to cut the columns (if we believe the values to cut them) then the block would fall immediately.

Not nice to make a joke, but if it serves to a lesson so be it. What I see in yur retort is a testament to the redundancy of the structure. Despite what many of you see as a sign of conspiracy I see as sign of man's ingenuity. I'm glad that the structure held as long as it did and allowed many to escape, instead of falling immediately and proving yur point.

[Furcifer]

Evidently the floor truss bolted connection to all columns transmits a shear force that compresses the column and a bending moment that bends the column.

Clarify please?

[Norseman]

According NIST the WTC1 impact cut 65% of the vertical columns of one wall while the other three walls were 100% intact.

I fully agree with NYFD that they could have handled the fires, i.e. contain them, stop them from spreading or let them burn out. No panic! I have actually been trained to do such jobs.


Heiwa, 3bodyproblem and bje called you on these two claims. But the words bluff or lie I would think is a far better word than the word claim in this case. When are you going to address them. We are still waiting.

[Heiwa]

Clarify please?

Basic! Shear force is the accumulation of vertical load (500 kgs/m²) on the floor truss that is transmitted to the column via the truss' end connection. It adds to the compression of the column. The shear force also produces bending of the truss around its neutral axis. Depending on the truss' end connection the bending moment may be transmitted to the column. If the end connection is, e.g. a pin joint - just one bolt - no bending moment is transmitted. If the end connection is a bolt + a small angle support some bending moment may be transmitted. I will now transfer to the 'Failure mode in WTC Towers thread.

[Dave Rogers]

Subject is collapse initiation and WTC1 is easiest to study, i.e. we can see on all videos how the roof drops for 4-5 seconds and there is still no damage at floor 93. In fact it appears that the top part of WTC1 above the initiation zone becomes 15 meters shorter while structure below floor 93 is still intact. And no structure above floor 93 is seen being pushed outwards.

So how can the top part lose 15 meters of its height in a few seconds? Did the walls bucklebend 180° inwards? Where did the floors end up. And what happened to the core? Did it bucklebend 180° utwards still inside the building?

I think you need to try to answer your own question here, Heiwa. So far you've said that none of the structural members buckled, that there was no damage to the initiation zone and that the building became 15 metres shorter despite the absence of any damage. Clearly, in the absence of any damage or buckling of structural members, the building could not have got 15 metres shorter. Therefore, what you've "proved" is that WTC1 is still standing.

Dave

[Heiwa]

I think you need to try to answer your own question here, Heiwa. So far you've said that none of the structural members buckled, that there was no damage to the initiation zone and that the building became 15 metres shorter despite the absence of any damage. Clearly, in the absence of any damage or buckling of structural members, the building could not have got 15 metres shorter. Therefore, what you've "proved" is that WTC1 is still standing.

Dave

You have to switch to the new thread, where somebody suggests that initiation was 'buckling' of the south wall and that the whole top part tilted to south, etc. You are 100% right that the building could not have become 15 metres shorter or mass/top above telescoped 15 metres into structure below in 2 seconds (viewed from the north) unless there were serious damages to all perimeter walls' and core's columns. But none are seen! And no columns from the relevant zone have been found in the rubble. Part of the mystery.

Real mystery is of course how this lightly stressed (compressed) structure would crumple in the first place. Do my model test to see that compressed columns do not crumple or disappear at 500°C.

[bje]

I think you need to try to answer your own question here, Heiwa.


Never expect answers from arrogant, discourteous Truthers. It's the nature of the beast.

[Heiwa]

Never expect answers from arrogant, discourteous Truthers. It's the nature of the beast.

Aha, the lying hoodlum henchman missed my reply 06.18 am. Sleeping again? Good night!

[Norseman]

Aha, the lying hoodlum henchman missed my reply 06.18 am. Sleeping again? Good night!
You are avoiding the question bje asked you a little bit earlier in the thread. And how many intact columns were there on the south side of WTC 1, you have not answered that question from 3bodyproblem either.

[pomeroo]

Evidently the top of WTC1 is 95% air volume wise. Then you have 4% concrete, glass, furniture, cabling, etc and 1% steel structure. Like most skyscrapers. And you can slam an airplane into it and destroy part of the steel structure and nothing happens due to structural redundancy. The tower was built very strong! Very low stresses in the structure.

The steel structure takes very little space so an aluminium/plastic plane cannot destroy many steel parts. Most fuel in the plane burns very quickly in a ball of fire and then a normal office fire starts. No big deal. Cannot harm the steel structure. It is like a fire in an iron stove. The stove does not melt, buckle or collapse. If you believe otherwise, you have been fooled.

But let's assume all the steel columns buckle in way of the impact/fire zone. The only result would be that the columns bend and crumple and that the top part of the tower above (95% air) moves down a little. The buckled columns will act as fenders and prevent damage of the tower below. If you believe otherwise, you have been fooled, I have to repeat.

My model will however demonstrate that the columns will not buckle due to the fire.

I have designed and built many steel ships with very good results so you do not have to worry about that. Sleep well.



You are incompetent to model the Twin Towers. You have provided ample proof of that fact. It's time you retired from the field, taking your agenda-driven preconceived conclusions with you.

[westprog]

Of course. That is the first I did (of course only two months ago when I first seriously studied the matter) ... and which NIST didn't do ... ever. See my paper! The top of WTC1 is 95% air! On top of a lightly compressed structure below. Nothing can happen.

And what value did you obtain for the potential energy of the portion of the buildings above the impact?

[westprog]

Most fuel in the plane burns very quickly in a ball of fire and then a normal office fire starts. No big deal. Cannot harm the steel structure. It is like a fire in an iron stove. The stove does not melt, buckle or collapse. If you believe otherwise, you have been fooled.


Heiwa, I've seen pictures like http://www.lmc.ep.usp.br/People/Valdir/imagens/fire/Madrid_Windsor.jpg

which appear to show steel buckling in an office fire. The structure appears to be collapsing. Am I mistaken in my belief?

[westprog]

And of course NIST never shows in its 10 000 pages report that the potential energy released did exceed the strain energy that could be absorbed by the structure.

Again, I look forward to seeing your value for the potential energy released.

[bje]

Aha, the lying hoodlum henchman missed my reply 06.18 am. Sleeping again? Good night!


The point is that you didn't miss my many questions over the last several weeks, Heiwa.

And you would not answer them, either. Are you now prepared to answer my questions and those of all the others here?

[westprog]

The point is that you didn't miss my many questions over the last several weeks, Heiwa.

And you would not answer them, either. Are you now prepared to answer my questions and those of all the others here?

I'm sure that Heiwa will be along shortly to address all these points. I'm especially interested in his observation that office fires cannot cause steel to buckle, and I'd like to compare his value for the potential energy contained in the portion of the WTC above the impacts with my own. No rush.

[metamars]

A fully dynamic analysis will utilize calculus to make dynamical evolution mathematically precise. If you study, e.g., the Ari-Gur/Singer paper, the question of subtracting a net plastic energy before or after a net elastic energy doesn't arise. Not in a simple way such as being discussed, anyway.

From their experimental results, seen in Fig. 2a, http://metamars.i8.com/ , at the particular spot in the rod that measurements were made, we can see that an elastic deformation and plastic deformation only overlap for about 1.5 msec. The elastic pulse preceeds the plastic pulse by about .5 msec. So, at least for the Ari-Gur/Singer scenario, it looks like you can say that, in some sense, you can subtract a portion of elastic energy before plastic energy.



I took a look at the Ari-Gur paper to try and quantitatively determine energy dissipation due to elastic vs. non-elastic dissipation.

The following is inexact - I am eyeballing a graphs to derive figures from it. I hope somebody else will follow up by studying the Ari-Gur paper, then giving either one of the authors a call, or else somebody else who actually works in the field of impact studies. I make assumptions that I'm not really sure about, so take with a grain of salt. I would appreciate it if other people studied this paper....

p. 622 of their paper (which I have uploaded) gives 2 compressive strain vs. time plots (side-by-side). The peak strain for the first plot is about 1000 mu, and the peak strain for the second plot is about 1500 mu. I'm not sure which test sample this is for. A pair of graphs on the bottom of p. 633 show experimental and theoretical graphs for one of the steel samples. Oddly enough, the theoretical graph seem to match the experimental graphs on p. 622 better (ignoring the inversion about the time axis.)

In any event, I referred to the theoretical graph, since I am eye-balling things, and this is the easiest to eyeball.


From the graph, the main elastic pulse is (very) roughly equal in area to a box 1000 mu high by .35 msec wide. Since the speed of sound in steel is 5,100 m/s, that means that the initial "pulse" is felt over a length of about 1.5 m. Since all the steel specimens were under 1 meter (max 380 mm), I take this to mean that it's a good approximation to consider the strain as being representative of the specimen as a whole, and furthermore that the rod can transfer elastic energy (to be calculated below) through the rod in an amount equal to 1.5 m/ 230 mm = 6.5 times the elastic strain energy corresponding to a 230 mm rod, compressed 1000 microns, statically. (Actually, this can't be correct, as I will show.)

Please note that I had previously thought that the pulses were smaller than the sample. Thus, I thought the pulses were mostly exiting out the bottom of the impacted rod, never to return.

Now, that seems to be definitely wrong! The fact that nobody ever questioned me on this point just shows, I think, why we need to talk to experts in the field. I don't know that anybody is looking at the relevant studies, besides myself, and I am clearly not a domain expert.

Anyway, rolling right along....

p. 623 has dimension and measurements of the various steel specimens being impacted. Using a middling one, Y5, I have a length of 230 mm, width 19.05 mm, and thickness 1.6 mm.

From Hooke's Law, using a constant of 10^9 N/m^2, I find that the elastic static strain energy is

(19.05 x 10^-3 m) * ( 1.6 x 10^-3 m ) (10^9 N/m^2) * (1,000 / 1,000,000) * (2.3 x 10^-1 m)


= 7.01 Newton


However, the Kinetic Energy is just 1/2 m v^2, where the striking mass has mass 180 grams and velocity 10.05 m/s

so KE = .5 * .18 kg * 100 m^2/s^2

= 9 Newton

Earlier, we saw that the "pulse" would have exceeded the length of the struck object. If we interpret this as meaning that 6.5 x the static strain energy is passing through this object, we end up with an energy sink greater than the energy source! Obviously, a contradiction.

That being the case, it seems unintuitive that the strain energy would "sit around" in the struck rod until after (9 Newton - 7.01 Newton) got dissipated in plastic strain, and then leave through the bottom of the rod. The plastic strain begins after the elastic loading begins, and it's oscillations "of consequence" continue after the main elastic pulse has terminated.

If the main elastic pulse had lasted about as long as the plastic strain oscillations, I would think it likely that all of the 'extra' (i.e., exceeding the static case) elastic energy goes into plastic strain. However, this isn't the case.

All of which means, I'm really not sure what becomes of the elastic energy.

As we are discussing energy dissipation in a collapse, and we want to try and get a handle as to how much elastic strain energy can pass through the bottom of the building via the columns, I would hope that I'm not the only one interested in quantitative experiments which can shed light on this.

N.B. : Ari-Gur never responded to my email inviting him to participate.

[metamars]

From Hooke's Law, using a constant of 10^9 N/m^2, I find that the elastic static strain energy is

(19.05 x 10^-3 m) * ( 1.6 x 10^-3 m ) (10^9 N/m^2) * (1,000 / 1,000,000) * (2.3 x 10^-1 m)


= 7.01 Newton


Actually, it's Newton-m, or Joules



However, the Kinetic Energy is just 1/2 m v^2, where the striking mass has mass 180 grams and velocity 10.05 m/s

so KE = .5 * .18 kg * 100 m^2/s^2

= 9 Newton


ditto