Architects, Engineers, and Scientists Analyze Failings of NIST's WTC 7 Final Report!

Originally posted by exponent

Well you're free to speculate all you like, but what is the point? It adds nothing to the discussion and can prove nothing?

The steel in 1975 had no fireproofing damage, the fire was fought and only occupied a relatively small area.

The steel had no fireproofing material on it in 1975 either.

The 1975 fire was not small, as it went from 11 th floor to 19th floor.

There was actually some minor damage which occurred, but it was not too serious.

You can't be making the argument that steel is invulnerable to fire, so you must be (unless I am mistaken!) making the argument that the fires on 911 were not significant enough to damage the steel. How do you resolve this with NISTs tests which do not agree with you?

The argument is like this.

Oswald shot Kennedy proved by Warren Commission.
No missle downed Flight 800 proved by Investigation.
McVay bombed Murah Building proved by investigation.
Terrorists bombed WTC 1993 proved by investigation.
Terrorists pulled off 911 proved by investigation.

So no the fires, which I have stated several times, in WTC1-2-7, were insufficient to cause buildings to fall.

Since this thread is in re: WTC7 then the fires were insufficient to collapse, disentegrate, pulverize, demolish WTC7.

Do you know the same engineers that investigated Murah are the same ones who investigated 911.

If the coroner is on your payroll you can get away with murder.

Did you go to the link and read the information/
The link that was posted twice on this page.

WTC7 exhibited eight characteristics of a controlled demolition. None of those eight points are sufficiently answered in the NIST report.

WTC7 exhibits eight characteristic signature events of controlled demolition. Since NIST mentions this once in their report and does not investigate that possibility, they have produced a prejudiced conclusion.

Originally posted by bsbray11

Originally posted by exponent
These trusses had only a few square inches of contact space to the rest of the steel in the towers, but hundreds of square inches of surface area which was involved in flame.

Just so no one is confused, NIST's failure mechanisms only needed trusses to be heated to the point of a certain amount of expansion (which they didn't really define) so that a certain amount of force would be applied laterally to the perimeter columns (also no calculations from NIST for that). Then the perimeter columns are somewhat deflected, and supposedly after so much of this (they also didn't say how many would need to be deflected or by how much) the "global collapse" ensued, which NIST simply called "inevitable," again without showing any work.

Just trying to make it clear that, not even the "official" reports are actually saying heat itself caused actual significant strength loss in the steel columns or even the trusses

Just so you're not confused, that's not the failure mode. The failure mode is that the floor trusses go into tension and, to put it in laymen's terms, act as ropes to support the core columns that are severed. This tension force is approximately 4 kips in the horizontal direction on each perimeter column. If the lateral bracing providing by the floors is compromised, such as if the trusses heat up and sag a bit, then the problem changes.

This is what happened.

I've even done calcs to verify it. newtonsbit.blogspot.com...

Originally posted by Newtons.Bit
I've even done calcs to verify it. newtonsbit.blogspot.com...

In a 600C fire, the Modulus of Elasticity will have reduced to approximately 0.3 of its original value, and the yield strength to 0.5 of its original value.

I see you haven't updated your blog yet as to this sentence. I have to wonder why you word this the way you do.

Wouldn't the correct way to say this be: If the steel becomes 600C.....?

And does that correlate to NIST's own findings?

Originally posted by Griff

Originally posted by Newtons.Bit
I've even done calcs to verify it. newtonsbit.blogspot.com...

In a 600C fire, the Modulus of Elasticity will have reduced to approximately 0.3 of its original value, and the yield strength to 0.5 of its original value.

I see you haven't updated your blog yet as to this sentence. I have to wonder why you word this the way you do.

Wouldn't the correct way to say this be: If the steel becomes 600C.....?

And does that correlate to NIST's own findings?

Well, not only that but I take issue with the magnitude of the affects to Young's modulus and yield strength. For instance, this shows the Young's modulus to drop from 32 Mpsi to 18 Mpsi for 1100 F (600 C). That's 56% of the original value - not 30% as stated.

www.engineeringtoolbox.com...

Also, this chart, which I have now posted in a half dozen threads like this



shows a reduction in yield strength to about 39% of the original.

So basically one is overstated and the other understated.

Still trying to figure out why we're talking about 600 C though - that doesn't go with the NIST report test results. We can make the towers do flips if we want to use data outside the NIST report. That would be beside the point (and the topic) though.

Newtons Bit,
Nice math. However it does not take into account that there are several core columns with I-beams attached horizontally to them and that the exterior columns also were stabilized by I-beams at the intersection of the floor truss and the exterior columns, and at the intersection of the floor trusses and the core columns.
It also assumes that a plane cut one of the core columns. And even if it did cut a core column, then explain how the core columns in the rubble piles were thirty feet long and so conveniently easily loaded on to disposal trucks.

Originally posted by bsbray11
That's easy: they kept modifying the simulation parameters. If you don't know what I'm talking about already, then someone else can post the relevant part of the NIST report or I can do it later. They assumed a priori that fire and impact damages caused the collapses, and then they kept simulating the fires on computers and increasing the amount of heat until they could start producing failures.

No they didn't, what they actually did is take reasonable error margins. Even so your argument is completely irrelevant, if they actually got failure within reasonable fire temperatures, then your complaint is invalid. If they manipulated the values outside the acceptable range then your complaint would be valid. Nobody has pointed out the latter despite many attempts.

If you're talking about actual lab tests, I would love to see the test where NIST showed expanding trusses deflecting perimeter columns.

That is not the failure mechanism, please read my previous posts!

Do you have any idea how showing that allows verifying their actual calculations or simulations independently? Why do you think it would be important to consider those kinds of calculations in the first place?

I'm not sure what exactly you're saying here, NIST have released model data that has been requested via FOIA. The software they use is all available. Why has nobody verified their actual simulations independently?

I actually didn't know this. Can you link to it? And does it add this force to the tensions from the spandrel plates and end-to-end connections (which would have tried to hold the columns in place)?

It's part of NCSTAR 1-6. I prefer not to give direct references as that encourages reading only a small section and then commenting. If you do not know this already, you need to read the report in more detail.

Bazant's work has been criticized for assuming variables where either experimental data or the actual structural documentation needs to be consulted, among other problems. The paper was written 2 days after 9/11, before any investigation whatsoever, and with absolutely no precedent on which to base the physics.

The first part of this quote is valid, and the last part slips into complete rubbish. While Bazants work did appear quickly, it's not based on unknown physical principles and since then his work has been repeated with more rigour by people such as Gregory Urich, Dr Frank Greening etc. All of these analyses agree with Bazant.

With regards to your link to 911research, the whole section starts with

Zdenek Bazant and Yong Zhou must be super-geniuses

This is not a serious critique.

But they physically found no evidence for this, or even for heating above around 200-300 C. Not to mention steel glows dark red in broad daylight at this temperature. In general it is an insane temperature to transfer to much steel, because of how much heat energy is required to do it.

I can show you steel in the Cardington tests reaching these temperatures within a few minutes. It's not insane at all and this is just your personal speculation. Provide some evidence from a non-truther source please.

Have you ever looked at that math? Would you be willing to or do you find yourself automatically assuming it's wrong and that NIST is still pure?

I'm confused as to how NISTs supposedly incorrect math could change how the fires performed in the physical tests they used to verify this. Care to give an explanation?

This next section is in reply to fmcanarney

The steel had no fireproofing material on it in 1975 either.

No that is incorrect

The 1975 fire was not small, as it went from 11 th floor to 19th floor.

This is also incorrect, it covered a few floors through a wiring duct

The argument is like this.
...
So no the fires, which I have stated several times, in WTC1-2-7, were insufficient to cause buildings to fall.

You've stated it, and lied [edit: should say presented lies, apologies about that] and misrepresented facts to support it. I'm fairly sure you can believe in something if you misrepresent the truth, but in reality virtually none of your points stand up to scrutiny.

For example, what evidence do you have that steel was unfireproofed in 1975, or do you just take it on faith that it was? Can you show me a single piece of reliable evidence that shows this? I suspect not.

With regards to your "8 features", I assume you're referring to ae911truth (although they list 10). Of their 10, the following are easily shown to be wrong: 1,2,4,5,6,7,8,10.

[edit on 14-9-2008 by exponent]

reply to post by Valhall


Interesting. Thanks Valhall.

I have computed the total deflection with the new numbers using the very same equations Newton used.

I came up with:

Deflection:

23PL^3/(1296EI)=23(6)(37x12)^3/(1296x18,000x739)=0.7 inches.

With a few iterations (8 to be exact) of the P-delta calculations (which I will not post at the moment but will scan them tomorrow if need be) with the new E and adjusted Mu+

I came to find the P-Delta deflection as .73-.74 inches.

Thus, having a total deflection of 1.43-1.44 inches. Not the 4.75 inches Newton calculated.

There's a pretty big difference there, I'd say.

Originally posted by Newtons.Bit
The failure mode is that the floor trusses go into tension and, to put it in laymen's terms, act as ropes to support the core columns that are severed.

What core columns were severed and how do we know?

Originally posted by exponent
No they didn't, what they actually did is take reasonable error margins.

Who decides what's "reasonable"? You? I asked you if you had seen the numbers on how energetic they assume those fires were, and you completely ignored my question.

if they actually got failure within reasonable fire temperatures, then your complaint is invalid.

The temperatures were not extraordinary, the amount of heat they assumed was.

If they manipulated the values outside the acceptable range then your complaint would be valid. Nobody has pointed out the latter despite many attempts.

How would you know?

I'm not sure what exactly you're saying here, NIST have released model data that has been requested via FOIA. The software they use is all available. Why has nobody verified their actual simulations independently?

Maybe a lack of structural documentation has something to do with it. Something to investigate?

The first part of this quote is valid, and the last part slips into complete rubbish. While Bazants work did appear quickly, it's not based on unknown physical principles

No, it isn't, but you don't know that you can apply them so simply to the towers falling, under some kind of assumed collapse mechanism that no one had even established yet. That was my point. There was not, and still isn't, a set of formulas with which you can just crank out a collapse scenario with any degree of certainty that it's going to bear any relation at all to reality. Computer simulations so far have only offered the first second or so of initiation. Even just the effects of impact-loading in steel structures is something new to engineering, as that was something the FEMA engineer Astaneh-Asl was studying in the lab a month before 9/11 took place.

and since then his work has been repeated with more rigour by people such as Gregory Urich, Dr Frank Greening etc. All of these analyses agree with Bazant.

That's your story. Neither of those people mean anything to me. They're JREF'ers. Greening is a chemist by trade and I've seen enough garbage from him, from his suggestions of thermite forming on its own in the towers to help bring them down, to dimensionless mathematical "models" of collapse scenarios that neglect just about everything you possibly could just to prove a (meaningless) point.

With regards to your link to 911research, the whole section starts with

Zdenek Bazant and Yong Zhou must be super-geniuses

This is not a serious critique.

Too good for sarcasm? Really? I thought they brought up good points, whether or not you refuse to consider them. We'll all just keep having disagreements so long as you keep avoiding what really stands out as "wrong" to us.

I can show you steel in the Cardington tests reaching these temperatures within a few minutes.

Yeah, but they were intentionally high-powered fires, which wasn't the case at the WTC. They did other tests at Cardington where it took 30 minutes or longer for segments (of MUCH THINNER) steel to reach those temperatures. What do you think made the difference?

It's not insane at all and this is just your personal speculation. Provide some evidence from a non-truther source please.

Here's the NIST excerpts:

A floor section was modeled to investigate failure modes and sequences of failures under combined gravity and thermal loads. The floor section was heated to 700 ºC (with a linear thermal gradient through the slab thickness from 700 ºC to 300 ºC at the top surface of the slab) over a period of 30 min. Initially the thermal expansion of the floor pushed the columns outward, but with increased temperatures, the floor sagged and the columns were pulled inward. (p 98/148)

A spray burner generating 1.9 MW or 3.4 MW of power was ignited in a 23 ft by 11.8 ft by 12.5 ft high compartment. The temperatures near the ceiling approached 900 ºC. (p 123/173)

Look up the power ratings for wood stoves. Let's say we use a 1500-watt stove as the reference (decently sized, look them up). So 1.9 MW of power is equivalent to over 1250 of these stoves. 3.4 MW is over 2250 of them.

So you think the fires in the WTC towers on 9/11 must have been equivalent to the energy of between 1250 and 2250 wood stove fires, per living-room size area. Right?

I'm confused as to how NISTs supposedly incorrect math could change how the fires performed in the physical tests they used to verify this.

Can you tell me where in the report they reproduced the collapse mechanism in a lab?

this was exponents comment:
It's not insane at all and this is just your personal speculation. Provide some evidence from a non-truther source please.

Providing some evidence from a "NON-TRUTHER" source.

1250 woodburning stoves in a living room sized structure is from a non truther source. It is from the NIST report.

I was telling him you did post from a nontruther source ---- the NIST report.

[edit on 14-9-2008 by fmcanarney]

reply to post by fmcanarney


Excuse me, I just posted NIST's own numbers and did simple division.

Is division the "truther source," or is NIST? Or can you not read?



Btw, 1250 is the lower bounds. I wonder why you automatically selected that one over the other when they both came directly from NIST?

[edit on 14-9-2008 by bsbray11]

Bsbray,
Took the figures out of NIST and calculated that between 1250-2250 wood burning stoves in a living room sized area each emitting 1500W of heat were used. Does this sound contrived and using any means to an end. Does the end "proving fires and damage caused demise of WTC7" justify employing that much heat to produce improbable temperatures?

The thread is not a discussion, it is several persons staunchly defending the official report.

Originally posted by bsbray11
Who decides what's "reasonable"? You?

No, the data coupled with engineer opinion does. If you know a value as 80 +/- 10, reasonable margins would be 70 and 90, unreasonable margins would be 50 and 120.

I asked you if you had seen the numbers on how energetic they assume those fires were, and you completely ignored my question.

I apologise, NISTs tests on multi-workstation compartments which you can find here: wtc.nist.gov...

The temperatures were not extraordinary, the amount of heat they assumed was.

If you're using Dr Greening's critique here, he incorrectly calculated the floor area as far as I know. Please feel free to be more specific.

How would you know?

Because I have been researching this issue for a couple of years? I have yet to see a reliable criticism of the reports which would change the conclusions. Do you believe there has been a serious challenge? If so could you cite please?

Maybe a lack of structural documentation has something to do with it. Something to investigate?

This was of course a trick question. There are plenty of fire, impact, collapse etc simulations. Edinburgh, Purdue, Weidlinger all conducted studies into 911 and managed to do just fine. In fact NISTs SAP2000 model gives you pretty much all the information you need to simulate the towers.

No, it isn't, but you don't know that you can apply them so simply to the towers falling, under some kind of assumed collapse mechanism that no one had even established yet. That was my point. There was not, and still isn't, a set of formulas with which you can just crank out a collapse scenario with any degree of certainty that it's going to bear any relation at all to reality.

They are quite simplistic, 1d models, but they do match the observations. I don't deny they can be improved and indeed Gregory Urich, Dr Greening et al have done a good job of trying to incorporate all possible variables.

Computer simulations so far have only offered the first second or so of initiation. Even just the effects of impact-loading in steel structures is something new to engineering, as that was something the FEMA engineer Astaneh-Asl was studying in the lab a month before 9/11 took place.

Well there's no denying that, nobody is claiming to know 100% of what is going on, simply that we have a very good explanation of collapse without need to invoke any supernatural elements like nano thermite or space beams. We can explain impacts, structural weakening and eventually collapse quite well with only things we have direct evidence for.

That's your story. Neither of those people mean anything to me. They're JREF'ers.

Gregory Urich is a member of scholars for truth and justice (I think, there are a few groups now).

Greening is a chemist by trade and I've seen enough garbage from him, from his suggestions of thermite forming on its own in the towers to help bring them down, to dimensionless mathematical "models" of collapse scenarios that neglect just about everything you possibly could just to prove a (meaningless) point.

Greening is also the source for your claims about heat output above as far as I know. Can you point out something they've ignored in their models? Lets bear in mind his paper was co-authored by Bazant, David B Benson etc. It has (as far as I know) been accepted for publication in a distinguished journal. You cannot simply dismiss their results with "oh I don't believe it therefore it's not true".

Too good for sarcasm? Really? I thought they brought up good points, whether or not you refuse to consider them. We'll all just keep having disagreements so long as you keep avoiding what really stands out as "wrong" to us.

Disparaging sarcasm indicates a rather poor bias, the page you're referring to has no calculations, and contains facts we can show are wrong (the idea that a 5 to 1 safety ratio is common). It is just speculation without any actual science to back it up.

Yeah, but they were intentionally high-powered fires, which wasn't the case at the WTC. They did other tests at Cardington where it took 30 minutes or longer for segments (of MUCH THINNER) steel to reach those temperatures. What do you think made the difference?

Can you show me a single instance of that? Even in the smallest fires last time I looked steel temperatures rose extremely rapidly.

Here's the NIST excerpts:

Look up the power ratings for wood stoves. Let's say we use a 1500-watt stove as the reference (decently sized, look them up). So 1.9 MW of power is equivalent to over 1250 of these stoves. 3.4 MW is over 2250 of them.

So you think the fires in the WTC towers on 9/11 must have been equivalent to the energy of between 1250 and 2250 wood stove fires, per living-room size area. Right?

No, you do not understand the purpose of these tests. Please go back and re-read what they were using them for.

Can you tell me where in the report they reproduced the collapse mechanism in a lab?

Of course they did not do this. Do you believe this is the only way to sufficiently verifiy their conclusions, or would you accept some more reasonable evidence?

edit: I should point out that this post was quite harsh in tone. I am just trying to get this reply finished quickly. I am more than happy to continue civil debate, but lets start citing and making points explicitly.

[edit on 15-9-2008 by exponent]

Originally posted by exponent
In fact NISTs SAP2000 model gives you pretty much all the information you need to simulate the towers.

Again, this is not what we are saying.

What we are saying is: It is impossible to peer review NIST's work with only NIST's data.

With my green sky analogy again: If I wrote a paper that the sky was green and all you had to go on was a picture that I painted with the sky being green, could you say my paper was false?

Well there's no denying that, nobody is claiming to know 100% of what is going on, simply that we have a very good explanation of collapse without need to invoke any supernatural elements like nano thermite or space beams.

Neither of which are "supernatural".

We can explain impacts, structural weakening and eventually collapse quite well with only things we have direct evidence for.

Only if your evidence shows heating to a certain temperature. Does it?

and contains facts we can show are wrong (the idea that a 5 to 1 safety ratio is common). It is just speculation without any actual science to back it up.

That is not the idea as far as I'm concerned. I believe the idea is that since the wind load would place a tremendous load on the exterior in hurricane force winds, by design, those exterior columns would have a high safety margin. Now, since the day wasn't windy, that reserve would be used for other loads. But, I will agree it's probably not 2000% more.

Of course they did not do this. Do you believe this is the only way to sufficiently verifiy their conclusions, or would you accept some more reasonable evidence?

It's not unreasonable to ask for empirical proof in the scientific method.

Please take my words with kindness also, I usually don't mean to be harsh, but it's difficult to not come accross that way on just internet forums.

Originally posted by Griff
Again, this is not what we are saying.

What we are saying is: It is impossible to peer review NIST's work with only NIST's data.

With my green sky analogy again: If I wrote a paper that the sky was green and all you had to go on was a picture that I painted with the sky being green, could you say my paper was false?

I understand your point, but I don't think you understand my response to it

If you presented me a paper, that said essentially "we use this painted picture as evidence the sky is green". I would respond simply "such a painting has no connection with reality, I could not repeat this painting and get the same result.

You've made the argument before that you think NISTs simulations were correctly presented, so I am confused as to what exactly your complaint is. There likely is no other data available on the construction of the building, and typical truther arguments have argued that NIST simply manipulated the starting conditions in order to induce a response. As you have structural data and seperate fire data, you can change this and induce smaller, cooler fires, less structural damage etc.

I am no engineer, but that's my understanding of this situation. I will help you attain any information you need to recreate this simulation, but I don't understand why you don't think it's possible.

Neither of which are "supernatural".

Actually they both are. Nano-thermites are cited as being able to create high explosive like blast effects, thermite like heat effects, all while being silent. These things are mutually exclusive, therefore supernatural.

Space beams exceed maximum power limits and there is no physical mechanism for 'dustification', therefore supernatural.

Only if your evidence shows heating to a certain temperature. Does it?

Sure, but I am sure you are going to debate this and say recovered steel samples only show low temperatures. This is true, but omits the fact that fire was clearly evident in large quantity, and that NISTs test fires show large amounts of heat release. Yes the evidence shows large amounts of heating, but it depends on what you consider 'evidence'.

That is not the idea as far as I'm concerned. I believe the idea is that since the wind load would place a tremendous load on the exterior in hurricane force winds, by design, those exterior columns would have a high safety margin. Now, since the day wasn't windy, that reserve would be used for other loads. But, I will agree it's probably not 2000% more.

Actually no you are correct that some of the live loads may have had huge amounts of safety margin, but the dead loads certainly did not. I'm not sure if the claims are intrinsically linked but they are both wrong, perhaps for different reasons.

It's not unreasonable to ask for empirical proof in the scientific method.

No it's not, but it is unreasonable to expect NIST to build any sort of large scale reproduction of the towers and attempt to reproduce conditions that day. I am sure you can't disagree with me on this can you?

Please take my words with kindness also, I usually don't mean to be harsh, but it's difficult to not come accross that way on just internet forums.

Noted, I do respect the fact you're an engineer, but if you look at what some of the people with appropriate credentials have said it makes you doubt. Argument by authority is not strong, and I'm glad you haven't fallen into the trap

Originally posted by exponent
If you presented me a paper, that said essentially "we use this painted picture as evidence the sky is green". I would respond simply "such a painting has no connection with reality, I could not repeat this painting and get the same result.

Can I not say the same of NIST? Can I repeat (or even them) this "simulation" in real life? That's my point. Also, the point of if you had no other reference to the physical reality that the sky is blue...you would have to accept my paper that the sky is green. Because this painting is the only reference available.

There likely is no other data available on the construction of the building,

So, NIST just made it up?

I will help you attain any information you need to recreate this simulation, but I don't understand why you don't think it's possible.

That's the point. Of course you can give me NIST's information to recreate their simulation and it will work. Question is: IS NIST'S INFORMATION CORRECT? And how do we know without verification?

Actually they both are. Nano-thermites are cited as being able to create high explosive like blast effects, thermite like heat effects, all while being silent. These things are mutually exclusive, therefore supernatural.

I'm not sure who claims that nano-thermate causes explosive like blasts?

Space beams exceed maximum power limits and there is no physical mechanism for 'dustification', therefore supernatural.

You know this as fact? Why have we been persuing these weapons for over 30 years then if they are unpracticle?

Actually no you are correct that some of the live loads may have had huge amounts of safety margin, but the dead loads certainly did not. I'm not sure if the claims are intrinsically linked but they are both wrong, perhaps for different reasons.

See this is where structural engineering comes into play. When designing, you have to look at all loads and what they do to a structure. This includes live, wind, dead, siesmic etc. loads. Then we design the structure for the maximum of these values. That includes bending, deflection, moment etc. So, when they say a member can withstand something, it means that that something is the ultimate and the other loads produce something less. Hence, if the wind load governs and the wind is not blowing that day, there is more capacity for other loads. Etc, etc.

No it's not, but it is unreasonable to expect NIST to build any sort of large scale reproduction of the towers and attempt to reproduce conditions that day. I am sure you can't disagree with me on this can you?

Yes, I can. Because it wouldn't take an entire structure to show a few columns bending inward from trusses pulling on them. BTW, how much have we spent on the war in Iraq? How many full towers could have been built with that money? So, yes, it's possible.

Noted, I do respect the fact you're an engineer, but if you look at what some of the people with appropriate credentials have said it makes you doubt. Argument by authority is not strong, and I'm glad you haven't fallen into the trap

I have always said I could be wrong in my convictions. See my signature about absolutes and people thinking they know everything.

reply to post by ThroatYogurt


Again i have pointed out to you at least a dozen times with no rebutal:

Just because a CT is debunked, the OS does not become proven. Thats not how science works and it never will be.

It is however how religion works. That is for another forum.

So, is nobody willing to debate Dr. Greening's calculations? If he is correct, that for the amount of heat that NIST suggests was in WTC7, it would have taken a fuel load of FOUR times what they calculated as available. I posted some quotes twice on the previous page(pg 9) with no rebuttal.
I will post a link again in hopes that some will take the time to read it and verify his math and conclusions. the911forum.freeforums.org...

Originally posted by exponent

Originally posted by bsbray11
Who decides what's "reasonable"? You?

No, the data

Data cannot interpret itself.

coupled with engineer opinion

There is nowhere near a consensus. Even the "official" side of things has so many contradictory details and assumptions, even just between the FEMA and NIST reports (neither of which peer-reviewed), there is no single "engineer opinion" you can refer to unless you play favorites, which of course you will. I still haven't seen any empirical precedent for using 3.4 MW of power.

There are plenty of fire, impact, collapse etc simulations.

There are also entire movies made in CGI without any regard to what is physically possible. That's why referencing structural documentation or anything that can be verified independently (and not just through NIST ) is important.

They are quite simplistic, 1d models, but they do match the observations.

Can you "observe" a 1-d model? What are you even talking about? There was debris ejection alone, of most of the towers' mass, that Greening completely neglects as he drops each floor onto the next without losing any mass the entire time. That is NOT realistic. I don't even have to mention any further problems with that idiot's work, he obviously does not pay attention to critical details.

Well there's no denying that, nobody is claiming to know 100% of what is going on, simply that we have a very good explanation of collapse

You mean of the initiation? (Not going so far as to call it "very good")

No one has ever analyzed global collapse beyond theoretical mathematics that have no empirical basis (Greening is a laughable example). NIST did not analyze global collapse. FEMA did not. I never did hear of a well-defined replacement for "pancake theory."

Greening is also the source for your claims about heat output above as far as I know.

No, and this is the 3rd time I've posted this. If you can read, those excerpts are from the NIST report, then I did simple division. That's where you see how many times one number, will "fit" inside the other number. I used a calculator program on my computer. I have a problem with the numbers I am looking at, because it does not look realistic and I am not seeing an empirical basis for this amount of heat.

Disparaging sarcasm indicates a rather poor bias, the page you're referring to has no calculations

I posted some numbers above following that web page, and it really wasn't that hard.

and contains facts we can show are wrong (the idea that a 5 to 1 safety ratio is common)

Common for skyscrapers that are the tallest in the world when they are built, or common for all buildings in general?

Can you show me a single instance of that? Even in the smallest fires last time I looked steel temperatures rose extremely rapidly.

Look through this temperature data from Cardington's office fire test and you will see multiple examples of maximum heating being after 30 minutes of direct exposure.

Test 4 : Office Fire Temperature Data

In fact, the first example took about 45 minutes to reach its max temperature, which was 580 C.

No, you do not understand the purpose of these tests. Please go back and re-read what they were using them for.

So if I waste my time going back and reading what exactly they were trying to find, am I going to be disappointed to find that cranking up the amount of heat to ridiculous levels is still playing a role in the results? Or am I going to see that the unrealistic heat is completely irrelevant to what they're doing?

Can you tell me where in the report they reproduced the collapse mechanism in a lab?

Of course they did not do this. Do you believe this is the only way to sufficiently verifiy their conclusions, or would you accept some more reasonable evidence?

It would have to be more than arbitrary numbers I'm afraid. Yes, there needs to be empirical data to back up everything they assume, no assumptions or getting to pick what seems "reasonable" to fit any given scenario.

Edit to clean up the code.

[edit on 16-9-2008 by bsbray11]