Critical Errors and Omissions in WTC7 Report Uncovered

[mynym]

But, at the end of the day, NIST were still correct...

In the end, there was never any way for NIST to be incorrect in any "critical" way in the first place.

You are inferring entirely different things when you wrongly claim their error to be "critical", as you well know. (We know the player made the break. He was the only person in the room.)

What would be critical or serve as a falsification of the NIST report?

Perhaps this will save everyone a lot of time, technical details... rhetoric and semantics: Nothing.

But that won't stop us from playing pretend and debating it as if there could be "critical" errors, apparently.

 

[Oxymoron]

The science in this case requires a developed understanding of situations, including that of the interactivity of components in a structure, and the understanding that conclusions about a specific instance within that structure cannot be extrapolated to the whole.

So you are saying that it is too chaotic to understand, especially as no one was there to see it and it is all reverse engineered to approximate what was visually seen from the outside.

Also required is a developed understanding of what follows after collapse, where the structure becomes a mechanism, with dynamic forces coming into play.

After the collapse of what exactly?

NIST does indeed deal with those understandings, and this thread doesn't.

They took years to come up with a simulation which has erroneous figures and the graphics do not match and any slight deviation from their 'magic formulation' would result in 7 STANDING.

It's not science. It's a fraudulent claim, with a hidden agenda.

Yes, this is exactly what we have been saying for years. The NIST report is not science, it is a fraudulent claim, (after their previous fraudulent claims were debunked), with a hidden agenda.

The errors and omissions "discovered" are insignificant. There never was a discoverable critical point to be found in the interior of a long-lasting wandering fire in a steel skyscraper.

But NIST claim there is and that they found it.

The failure ensued from a myriad of events occurring not just at the girder, but on the floor above and below,

Great so it happened over many hours, not in seconds? Where and when, talk us through it.

due to unprecedently high temperatures, due to a long-standing FIRE.

And what exactly is unprecedented about the temperature and the "long-standing" FIRE?

It fascinates me. Or, rather, all pseudoscience does.

Agreed, makes me wonder how they get away with it even on part of the population.

 

[gerrycan]

But the claim that it is a critical error *is* rhetoric, so it's appropriate to address that part in kind.

The explanation of the initiating event supposed by NIST to have occurred in WTC7 in their report is invalidated given the information in the structural drawings for the building. The discrepancies between the two. when accounted for in their analysis, is critical to it. These errors and omissions are critical, and invalidate the claim by NIST that the girder between C79 and C44 could walk off the connection seat at C79 by way of thermally expanding beams to the east of it. If anyone wants to dispute that in a meaningful way, they should do so with data and figures, not with rhetoric, I agree with you there.

 

[Pete Tar]

Is it proven that they used the wrong figure in the detailed simulation and report, or was it just in the summary that the wrong figure showed up? That's what I gathered from Mick.

Is it proven that you have invalidated the claim the girder could walk off due to heat expansion given the presence of the correct dimensions/structure, or do you just personally find it 'unlikely'?
It could still have walked off due to other stresses present in combination with fire expansion couldn't it, or do those corrections make movement/failure impossible?

(sorry if you have to repeat yourself, but a summary with regard to those specific points might be handy.)

 

[Jazzy]

But the claim that it is a critical error *is* rhetoric, so it's appropriate to address that part in kind.

And there's absolutely no need to go further.

This guy has avoided answering more than forty questions of mine, on the way to delivering "work" less exacting than material I was playing with more than half a century ago. I have nothing other than that to say.

[...]

 

[gerrycan]

Is it proven that they used the wrong figure in the detailed simulation and report, or was it just in the summary that the wrong figure showed up? That's what I gathered from Mick.

Is it proven that you have invalidated the claim the girder could walk off due to heat expansion given the presence of the correct dimensions/structure, or do you just personally find it 'unlikely'?
It could still have walked off due to other stresses present in combination with fire expansion couldn't it, or do those corrections make movement/failure impossible?

(sorry if you have to repeat yourself, but a summary with regard to those specific points might be handy.)

I don't mind repeating it. The original claim by NIST was that the seat plate was 11" wide, and that once the girder had shifted 5.5" and its web was no longer directly above the plate, the girder failed. When it was pointed out to them that the seat plate width was actually 12" on the correct structural drawing, they couldn't reasonably dispute that, after all, it is on the structural drawings that they claim to have based their analysis on. The important thing to note is that if NIST had reached the figure of 5.5" for expansion by using the element dimensions and their own temperature claims, how could they possibly adjust that claim to accommodate for the increase in the seat width, ie the girder has to walk further now, 6.25" according to NISTs erratum statement. They attribute this to a typo. When you check the elements with their temperatures for maximum unrestrained expansion it can't even get near 5.5 never mind 6.25".
When you look at their model illustrations in the report, they have the connection totally wrong. The lower plate is off by 90 degrees in one of them. Given that there are no stiffener plates visible anywhere and the implications that has for the walk off theory. In illustrations and simulation screenshots from NIST, the connection is wrong. When the connection is analysed on paper, and an FEA, the connection doesn't get near failing. It doesn't fail when subjected to NISTs conditions. If NIST truly are concerned enough about public safety not to want to jeopardise it, they should be equally as vigorous in protecting it by investigating the destruction of building 7 competently and transparently. A good start would be for them to comment about the implications that this data, in particular, the stiffeners, has for their thermal expansion claims.

 

[Mick West]

Jazzy has a one week ban for violations of the politeness policy.

 

[Pete Tar]

So Mick, is it true that the error is used in the meat of the investigation, or was it just the less-thorough summary?
With reference to what you said here...
(Or is this discussing a different point?)

Here's what I think happened, and I admit from the start it sounds a little silly, but that's only because it accounts for human failings in paraphrasing and reducing a description of huge complexity.

• NCSTAR 1-9 "Structural Fire Response and Probable Collapse Sequence of World Trade Center Building 7" is the comprehensive report on the collapse
• NCSTAR 1-A "Final Report on the collapse of WTC7" is essentially a summary of this and other reports.

1-A-Final sums up about 100 pages of 1-9-Structural with a couple of paragraphs:

Fire-induced thermal expansion of the floor system surrounding Column 79 led to the collapse of
Floor 13, which triggered a cascade of floor failures. In this case, the floor beams on the east side of the
building expanded enough that they pushed the girder spanning between Columns 79 and 44 to the west
on the 13th floor. (See Figure 1–5 for column numbering and the locations of girders and beams.) This
movement was enough for the girder to walk off of its support at Column 79.

The unsupported girder and other local fire-induced damage caused Floor 13 to collapse, beginning a
cascade of floor failures down to the 5th floor (which, as noted in Section 1.2.3, was much thicker and
stronger). Many of these floors had already been at least partially weakened by the fires in the vicinity of
Column 79. This left Column 79 with insufficient lateral support, and as a consequence, the column
buckled eastward, becoming the initial local failure for collapse initiation.

This summation of 1-A-Final give undue weight to the effects the 79-44 girder, giving the impression that the girder actually fell, and made the floors below it collapse. Hence the importance people place on how far it was pushed.

In fact the simulation and the information in 1-9-Structural show that the girder did not initially fall. What fell were the beams and girders affected by "other fire-induced local damage". Including on the floor ABOVE the girder.

The 79-44 girder was again given undue focus in the NIST WTC7 Tech Briefing. But again they did not say the girder fell. They did not say the falling girder triggered the collapse.
https://www.metabunk.org/files/NIST_WTC7_Tech_Briefing.pdf

And the actual technical briefing was very simplistic, and not very good.


So when we discuss what "NIST claims", we should look at their detailed claims, not the summary, and not a slideshow.

 

[Mick West]

So Mick, is it true that the error is used in the meat of the investigation, or was it just the less-thorough summary?
With reference to what you said here...
(Or is this discussing a different point?)

Gerry suggests two "critical" errors, the width of the seat, and the presence of stiffener plates.

NIST says they had the width of the seat correct in the simulation.

NIST gives no indication that they had stiffener plates, and their own rendering indicate they were not in the simulation. So if the stiffener plates were actually there, then this probably means that they used the wrong failure criteria for that particular failure mode of that particular connection.

I suggest it does not really matter, as they were just using that as a hypothetical for a narrative, and it does not appear to fail in that way in the full simulation. However they way they discuss it make it seem a lot more important that it actually was.

 

[Oxymoron]

I suggest it does not really matter, as they were just using that as a hypothetical for a narrative, and it does not appear to fail in that way in the full simulation. However they way they discuss it make it seem a lot more important that it actually was.

Does anything really matter when you apply the standards of 'hypothetical narrative'... aka 'Official Story'.

Seriously, what would it actually take for you to say... 'that was a serious omission' or 'no that doesn't work with these figures, their argument is seriously flawed'?

 

[Mick West]

Does anything really matter when you apply the standards of 'hypothetical narrative'... aka 'Official Story'.

Seriously, what would it actually take for you to say... 'that was a serious omission' or 'no that doesn't work with these figures, their argument is seriously flawed'?

Something that would prevent the building falling.

 

[Oxymoron]

Something that would prevent the building falling.

You could have been a politician

Could you give an example of something that may, in your opinion, fit that criteria?

 

[Mick West]

You could have been a politician

Could you give an example of something that may, in your opinion, fit that criteria?

Fully moment resisting connections internally. As it was numerous connections failed to some degree because they were just knife or seated connections. If it was revealed they were actually all moment connections then the building would almost certainly not have fallen.

 

[Oxymoron]

Fully moment resisting connections internally. As it was numerous connections failed to some degree because they were just knife or seated connections. If it was revealed they were actually all moment connections then the building would almost certainly not have fallen.

I love the little caveats there... "would almost certainly not have fallen" & "actually all moment connections"

So even then it is vaguely possible even if unlikely?

Which could have been said 'as is', because previously, (and since), no high rise building has collapsed completely due to fire.

OOI, could you give an example of a high rise building which incorporates "Fully moment resisting connections internally."

 

[Mick West]

I love the little caveats there... "would almost certainly not have fallen" & "actually all moment connections"

So even then it is vaguely possible even if unlikely?

It's always best to allow uncertainty, even if it's very small. Once you've fallen into the pit of certainty, it can be hard to get back out.

Which could have been said 'as is', because previously, (and since), no high rise building has collapsed completely due to fire.

OOI, could you give an example of a high rise building which incorporates "Fully moment resisting connections internally."

First Interstate Bank. Or any tall building in an earthquake zone.

 

[gerrycan]

It's always best to allow uncertainty, even if it's very small. Once you've fallen into the pit of certainty, it can be hard to get back out.



First Interstate Bank. Or any tall building in an earthquake zone.

You have seen the drawings for the bank? You just made a huge claim there Mick, that the designers of WTC7 blundered with their design of the internal connections. Please explain specifically what difference these types of connections would have made to NISTs analysis re girder walk off.

 

[Mick West]

You have seen the drawings for the bank? You just made a huge claim there Mick, that the designers of WTC7 blundered with their design of the internal connections. Please explain specifically what difference these types of connections would have made to NISTs analysis re girder walk off.

http://www.lafire.com/famous_fires/1988-0504_1stInterstateFire/ExSummary/LAFD-ExecutiveSummary.htm

The Tower is constructed of structural steel moment-resisting space frame and composite concrete and steel decking.

Moment resisting connections are much more resistant to failure than seated or knifed connections.

WTC7 was not in an earthquake zone. Who said they blundered? Sure they did not anticipate the full consequences of thermal expansion and progressive collapse, but nobody did.

 

[gerrycan]

Are you suggesting that the design engineers for WTC7 should have designed for a supposed event that is clearly impossible and also unprecedented. Buildings have to move Mick.

they did not anticipate the full consequences of thermal expansion

You agreed earlier in this thread that the maximum expansion that could happen in the beams was way less than NIST supposed it was.
Therefor they did. Mick, you are having real trouble admitting that NIST got this wrong. At some point, you need to face some hard facts. In the past you have been able to survive by repeating NIST mantras at people, but that tactic will not work for this thread, as you have found out.

 

[Hitstirrer]

Sure they did not anticipate the full consequences of thermal expansion and progressive collapse, but nobody did.

Why was that ?

Could it be because it had never happened before ?

Just on 9/11- the third building in history to fall due to fire - all three on the same day, and the very first due to a 'new phenomenon'.

Would it be reasonable for any designer to anticipate those odds ?

 

[gerrycan]

If only someone had told those highly qualified structural design engineers about thermal expansion, they could have left expansion gaps........oh wait a minute. Mick what was that maximum expansion figure again?

 

[Mick West]

Why was that ?

Could it be because it had never happened before ?

Yes. That's exactly why.

Just on 9/11- the third building in history to fall due to fire - all three on the same day, and the very first due to a 'new phenomenon'.

Would it be reasonable for any designer to anticipate those odds ?

No, it would not.

 

[Mick West]

Are you suggesting that the design engineers for WTC7 should have designed for a supposed event that is clearly impossible and also unprecedented. Buildings have to move Mick.
You agreed earlier in this thread that the maximum expansion that could happen in the beams was way less than NIST supposed it was.
Therefor they did. Mick, you are having real trouble admitting that NIST got this wrong. At some point, you need to face some hard facts. In the past you have been able to survive by repeating NIST mantras at people, but that tactic will not work for this thread, as you have found out.

It's not a tactic. This is not a high-school debate.

You (and to a certain extent NIST) are focussing too much on this one "walk-off". The bigger picture is that multiple connections would have failed in the fire.

 

[Hitstirrer]

The bigger picture is that multiple connections would have failed in the fire.

Why don't NIST agree with you ?

Why do they point specifically to a single connection ?

Your bare assertion that 'multiple connections would have failed' isn't backed by either calculations, evidence, or even the support of NIST.

 

[Oxymoron]

Who said they blundered? Sure they did not anticipate the full consequences of thermal expansion and progressive collapse, but nobody did.

Why was that ? Could it be because it had never happened before ?

Yes. That's exactly why.

If only someone had told those highly qualified structural design engineers about thermal expansion, they could have left expansion gaps......

Is the cart not going before the horse here? i.e. could it be the other way around...(I know that was your point gerry but just to drive it home).

'It had never happened before', (collapse due to fire), because they had always envisioned that and had always taken it into account in the design and build, making proper connections and allowing for expansion, (I know it sounds a bit avante guard), using appropriate fire retardents and steel thicknesses... meaning that when high rise buildings catch fire... as they do and has happened many times... they do not collapse in a heap at near freefall acceleration.

Someone somewhere obviously takes these factors into account and 'anticipate', or they would all fall down from roaming office fires.

 

[Mick West]

Why don't NIST agree with you ?

They do.

Why do they point specifically to a single connection ?

Because they wanted to describe a "probable collapse sequence".

Your bare assertion that 'multiple connections would have failed' isn't backed by either calculations, evidence, or even the support of NIST.

 

[gerrycan]

It's not a tactic. This is not a high-school debate.

You (and to a certain extent NIST) are focussing too much on this one "walk-off". The bigger picture is that multiple connections would have failed in the fire.

You're right, this is indeed not a high school debate. This thread is about NISTs hypothesis re the collapse of WTC7 and what they focused on. As you correctly state, NIST focused on the 'walk off' theory, and proposed it as a collapse initiation mechanism. I therefor focused in on this hypothesis, which i think is a reasonable thing to do. At the start of this thread, you presumably believed the walk off theory, mainly because you hadn't examined it. When presented with data that clearly does debunk it, you are now making excuses for NIST and trying to shift the goalposts. This is the kind of thing that you could maybe forgive in a high school debate, but not here.
You have questioned this right from the start, as you should, and your questions have been answered. The answers that you go do not agree with your agenda re NIST and WTC7 so now you are moving the focus. The hard facts are that NIST DID make critical errors and omissions in their report, and you don't want to admit it. However, this is not a high school debate, and even if you don't like the answers that you get, that does not exclude you from either accepting those answers or disputing them. You tried to debunk the information and failed, and are now running from NISTs own conclusions and saying that they over focused on this connection. And for some reason, suppose that i should not also focus in on that connection to examine their hypothesis. Fair enough, it isn't a high school debate, but it does a good impression at times. If it were a proper debate though, and we had a neutral party who had to conclude on the info so far, they would clearly uphold the title of this thread as true. The fact that you obviously do not, is starting to erode your credibility.

 

[Mick West]

Someone somewhere obviously takes these factors into account and 'anticipate', or they would all fall down from roaming office fires.

We've been over this before. This was a novel event. It was unanticipated. Recommendations were made to change building codes based on lessons that were learned.

 

[gerrycan]

We've been over this before. This was a novel event. It was unanticipated. Recommendations were made to change building codes based on lessons that were learned.

So what was different about WTC7 as compared to every other highrise that has survived fire?

 

[Mick West]

You're right, this is indeed not a high school debate. This thread is about NISTs hypothesis re the collapse of WTC7 and what they focused on. As you correctly state, NIST focused on the 'walk off' theory, and proposed it as a collapse initiation mechanism. I therefor focused in on this hypothesis, which i think is a reasonable thing to do. At the start of this thread, you presumably believed the walk off theory, mainly because you hadn't examined it. When presented with data that clearly does debunk it, you are now making excuses for NIST and trying to shift the goalposts. This is the kind of thing that you could maybe forgive in a high school debate, but not here.
You have questioned this right from the start, as you should, and your questions have been answered. The answers that you go do not agree with your agenda re NIST and WTC7 so now you are moving the focus. The hard facts are that NIST DID make critical errors and omissions in their report, and you don't want to admit it. However, this is not a high school debate, and even if you don't like the answers that you get, that does not exclude you from either accepting those answers or disputing them. You tried to debunk the information and failed, and are now running from NISTs own conclusions and saying that they over focused on this connection. And for some reason, suppose that i should not also focus in on that connection to examine their hypothesis. Fair enough, it isn't a high school debate, but it does a good impression at times. If it were a proper debate though, and we had a neutral party who had to conclude on the info so far, they would clearly uphold the title of this thread as true. The fact that you obviously do not, is starting to erode your credibility.

Your opinion on my credibility is neither here nor there in the grand scheme of things. The real questions are

• Is the stiffener plate issue really "critical" to the extent it requires a new investigation?
• How do you effectively communicate this to people if it is.

 

[Mick West]

So what was different about WTC7 as compared to every other highrise that has survived fire?

Don't you know? Surely you've looked this up by now.

 

[gerrycan]

Specifically Mick, what was different that allowed the building to collapse like this. Let's not do the high school thing any more. Straight question.

 

[Mick West]

Specifically Mick, what was different that allowed the building to collapse like this. Let's not do the high school thing any more. Straight question.

I wanted to know if you actually did not know, or if you were asking me for rhetorical purposes.

WTC7 had long span asymmetric framing with simple interior connections. First Interstate Bank and One Meridian Plaza had short span symmetric framing with fully restrained moment connections.

Were not not aware of this?

 

[gerrycan]

What you do not address is the fact that WTC7 did not collapse for the reasons that NIST suppose. I do not actually believe that you have seen the drawings for either of the 2 buildings that you use for comparison, But you have seen the drawings for WTC7 now, because I showed you them. I also showed you that these beams were not long enough to expand the way that NIST said they did. You even insisted on doing the sums yourself, and came to the exact same answer.
You cannot address this, from NIST in NCSTAR 1-9, which by your own posts on this thread, you admit is in error.

You also cannot deny that thermal expansion was at the heart of NISTs explanation, this makes the fact that you are clinging to the long span mantra a total contradiction. See this :

Now you are running from the walk off theory because you and NIST have been so thoroughly debunked. That is why you cannot deal with this, from NIST:

Also, you need to deal with this statement where NIST actually admit that they were unable to model the connection details accurately :

At some point, you need to really have this debate, and make tough admissions re the tough questions that you remain unable to answer.

 

[Mick West]

You asked about building differences. Did you have a point? Or were you really not just aware of the differences?

 

[gerrycan]

You asked about building differences. Did you have a point? Or were you really not just aware of the differences?

I know what NIST said, I just wanted to make the point that you'd repeat it, which you did. You have asked about the 'target element size' thing, it is right there above in my last post. NISTs models, which you selectively rely on, and NISTs words, which you are also very selective with, both contain critical errors/omissions that you are unable to deal with. All you have is NISTs original claims. You cannot explain these claims and justify them in the light of the data that I have given you in this thread. You are unable to quantify the difference that this data would make. All you have is NISTs original claims to fall back on, and that won't work any more. Debunked.

 

[Mick West]

I know what NIST said, I just wanted to make the point that you'd repeat it, which you did. You have asked about the 'target element size' thing, it is right there above in my last post. NISTs models, which you selectively rely on, and NISTs words, which you are also very selective with, both contain critical errors/omissions that you are unable to deal with. All you have is NISTs original claims. You cannot explain these claims and justify them in the light of the data that I have given you in this thread. You are unable to quantify the difference that this data would make. All you have is NISTs original claims to fall back on, and that won't work any more. Debunked.

I'm really not following your argument here.

Yes, thermal expansion is at the heart of NISTs explanation. As are the long spans, and the simple connections, and the asymmetric framing. But all those things existed. So what have you debunked?

You have possibly debunked the failure criteria for one connection in one direction for one mode of failure. That's really it.

You then ignore everything else that might possibly have failed, and declare the entire investigation null and void.

 

[Mick West]

And NIST's explanation about target element size is perfectly reasonable. Of course they could have modelled in finer detail. They did not because of limits on the total number of elements, not because of a limit on the size of elements.

1-9, p544 (pdf 610)

To model the damage and sequence of failures in WTC 7 following the initial failure event, failure
models were used within the framework of the LS-DYNA finite element analyses. For the global
collapse analyses of WTC 7, shell element sizes were 6 in. to 12 in. to maintain a model size of
approximately 3 million elements (see Table 12–1). With this resolution, the gradients around a fracture
could not be accurately resolved, and the damage criteria required adjustment to obtain the appropriate
strength and ductility of the structures (see NIST NCSTAR 1-2B). Simulating the global response of
WTC 7 required the same level of refinement throughout the model.

 

[gerrycan]

You have possibly debunked the failure criteria for one connection in one direction for one mode of failure. That's really it.

(my bolding) You should withdraw all of that post, but the bolding bit shows just how little you understand about the structural reality of the NE of WTC7. I think people can see quite clearly if they look at this thread just how thoroughly this has been debunked. This is not impolite, it is reality : the bolded bit above betrays the lack of of any engineering credibility that if you did posses, would have motivated you to run a mile from this debate. I notice that you are starting to do this now. To be honest, i don't blame you. So would I, if I were defending a lie as pathetic as NISTs.

 

[gerrycan]

And NIST's explanation about target element size is perfectly reasonable. Of course they could have modelled in finer detail. They did not because of limits on the total number of elements, not because of a limit on the size of elements.

1-9, p544 (pdf 610)

To model the damage and sequence of failures in WTC 7 following the initial failure event, failure
models were used within the framework of the LS-DYNA finite element analyses. For the global
collapse analyses of WTC 7, shell element sizes were 6 in. to 12 in. to maintain a model size of
approximately 3 million elements (see Table 12–1). With this resolution, the gradients around a fracture
could not be accurately resolved, and the damage criteria required adjustment to obtain the appropriate
strength and ductility of the structures (see NIST NCSTAR 1-2B). Simulating the global response of
WTC 7 required the same level of refinement throughout the model.

So the bit that they chose not to model in finer detail is the bit that they say is the most important to their explanation. That makes less sense than a chocolate firegaurd Mick.

 

[Mick West]

(my bolding) You should withdraw all of that post, but the bolding bit shows just how little you understand about the structural reality of the NE of WTC7. I think people can see quite clearly if they look at this thread just how thoroughly this has been debunked. This is not impolite, it is reality : the bolded bit above betrays the lack of of any engineering credibility that if you did posses, would have motivated you to run a mile from this debate. I notice that you are starting to do this now. To be honest, i don't blame you. So would I, if I were defending a lie as pathetic as NISTs.

Veering towards the ad hom there gerry. Let's keep it factual.