Critical Errors and Omissions in WTC7 Report Uncovered

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FORCES FROM THERMAL EXPANSION FAILED THE GIRDER AT COLUMN 79, THEN PUSHED THE GIRDER OFF ITS SEAT - NIST
 
the real pretext of the 4 part video series playlist is to give the impression that fires can't cause a building to collapse. The problem for those insisting on that false premise is the vulnerability to fire was not limited to a single point or a single event. As you point out, fire caused multiple structural failures within the building and that point undermines the central notion they want to put forth, I think that is why you are getting such resistance and being accused of being Orwellian. They wanted to give the impression that the whole case about if fire can weaken or did weaken a structure is dependent on a single event, or specifically the false impression that the whole case of whether fire weakened the WTC 7 structure (was) dependent on a single fluke event which they seek to disprove.

The objective of the videos I think was to push the notion of "see, fires shouldn't have caused the building to collapse" when in fact there were multiple examples of failures on several floors. The thing is even if the specific seat at column 79 didn't fail, it is not like saying there wouldn't have been a collapse because more failure could have occurred since multiple failures had already been occurring.

And that bias against admitting that fire can cause collapse or even local collapse is evident in how the videos talked about WTC 5 because very clearly the video gives the false impression that there were not fire induced failures in WTC 5. It surely doesn't explain that within WTC 5, several floors failed and collapsed due to fire.
Neatly analyzed and well put. Great.
 
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.
Content from External Source
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.
 
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FORCES FROM THERMAL EXPANSION FAILED THE GIRDER AT COLUMN 79, THEN PUSHED THE GIRDER OFF ITS SEAT - NIST

How could they "fail the girder" and THEN push it off its seat?

Edit: oh, you mean this slide from the tech briefing:


How far "off" did they push it? In which simulation? The most detailed simulation did not push it off. Just broke the bolts, and it was "rocked" off later.
 
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How could they "fail the girder" and THEN push it off its seat?

Edit: oh, you mean this slide from the tech briefing:


How far "off" did they push it? In which simulation? The most detailed simulation did not push it off. Just broke the bolts, and it was "rocked" off later.

No NIST assert the rock off thing as an alternative hypothesis and the beam stubs prevent this from happening.
 
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Would you agree that in the simulation video you posted, the 79-44 girder does not seem to play a large role in the floor collapses?

Now if the girder had only been pushed one inch (enough to break the erection bolts), then what effect would it have on the subsequent global collapse?

Looks like none to me.
 
Would you agree that in the simulation video you posted, the 79-44 girder does not seem to play a large role in the floor collapses?
I think that the simulation is unrealistic. It does not support what anyone is saying about the collapse of the building, NIST or otherwise.

Now if the girder had only been pushed one inch (enough to break the erection bolts), then what effect would it have on the subsequent global collapse?
Looks like none to me.
NIST said it was pushed further though. They said 5.5". Then they said 6.25". IF it had only been pushed 1" then it would have provided the lateral support to the column that NIST said was absent, so allowing it to buckle.


Here's how I see it Mick, and you really need to just say your mind this time, because I am getting pretty close to just clicking the red x here to be honest.

NISTs assertion - The column (79) buckled. It did so because it was not supported laterally. It lost this support because of girders that provided that support failing. The first one to do so was the girder at floor 13 spanning 79 and 44. This failed because of thermal expansion from floor beams to the east of it.

You need to state once and for all whether you agree with this or not.
 


The most detailed simulation did not push it off. Just broke the bolts, and it was "rocked" off later.
Quite likely because immediately prior to collapse the fire moved leftward, to the left of column 79, forcing (by expanding the beams in that area) the column center towards the top right.

Which I mentioned some time ago. It feels like years.
 
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NISTs assertion - The column (79) buckled. It did so because it was not supported laterally. It lost this support because of girders that provided that support failing. The first one to do so was the girder at floor 13 spanning 79 and 44. This failed because of thermal expansion from floor beams to the east of it.

You need to state once and for all whether you agree with this or not.

Actually NIST says the first girders to fail were the 81-26 girders on floors 13 and 14, at 3.5 hr (in Case B, which is what was carried forward to LSDYNA)

1-9-Structural 524 (pdf 590)

After 3.5 h of heating, the fire had damaged the floor beams, girders and floor slab sections on Floors 8,
12, 13, and 14. The girders bracing interior Columns 79, 80, and 81 were still intact, except for the girder
between exterior Column 26 and interior Column 81, which had buckled and walked off of the bearing
seat on Floors 13 and 14.
At the seated connection at Column 79, all the bolts had sheared on Floor 13
and two to three bolts had sheared on Floors 12 and 14. Approximately one-half to three-quarters of the
east floor beams had a connection damage level of 0.75-0.99 on Floors 11, 12, 13, and 14.
Content from External Source
Then on floor 12 at 4.0 hr (along with 79-44), and a lot of the beams and girders damaged or failed.

By 4.0 h of heating, there was substantially more damage in the WTC 7 structural system, particularly the
loss of lateral support to Column 79 after the failure of girder connections at Floors 10, 11, 12, and 13.
Floor beams, girders and floor slab sections at Floors 8, 10, 11, 12, 13, and 14 were damaged in the
vicinity of Column 79, primarily from the effects of thermal expansion within the structural system. All
the north-south girders framing into Columns 79, 80, and 81 on Floor 13, and the east floor beams, had
been damaged. The girder between Columns 44 and 79 had walked off the bearing seat at Column 79 on
Floor 13,
and all 4 bolts had failed on Floor 14 and two to three bolts had failed on Floor 12 at this seated
connection. The girder between Columns 79 and 80 and Columns 80 and 81 had buckled on Floor 13.
The girder between Columns 81 and 26 had buckled and walked off the bearing seat on Floor 12.
Approximately one-half to three-quarters of the east floor beams had a connection damage level of 0.75-
0.99 on Floors 11, 12, and 14
Content from External Source
There is no suggestion of the 79-44 girder failure being a triggering event.
 
There is no suggestion of the 79-44 girder failure being a triggering event.

"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 connecting Columns 79 and 44 to the west on the 13th floor."
"The displaced girder and other local fire-induced damage caused Floor 13 to collapse, beginning a cascade of floor failures down to the 5th floor ... This left Column 79 with insufficient lateral support in the east-west direction. The column buckled eastward, becoming the initial local failure for collapse initiation." NCSTAR 1-A, p 19-20

As you said yourself earlier, there's not much point in arguing semantics Mick.
 
You are quoting from the summary yet Mick explained NCSTAR 1-9 "Structural Fire Response and Probable Collapse Sequence of World Trade Center Building 7" is the comprehensive report on the collapse:

Initial Local Failure for Collapse Initiation

An initial local failure occurred at the lower floors (below Floor 14) of the building due to fire-induced floor failures, leading to buckling of a critical column (the initiating event) which supported a large-span floor bay with an area of about 200 m2 (2,000 ft2).

The leading hypothesis for the failure sequence that characterized the initial local failure was based on fire-induced failure events in the tenant floors. Floor beams, girders, slabs, and connections heated more quickly and to higher temperatures than the columns. Elevated temperatures in the floor elements led to thermal expansion, with or without thermal weakening and sagging, which resulted in failure of floor connections and/or buckling of floor beams. Sufficient floor component failures (connections and/or beams) resulted in at least one unsupported column over multiple floors at the lower floors. This column buckled and led to the initiation of global collapse."
NIST NCSTAR 1-9, WTC Investigation 323

World Trade Center 5

The World Trade Center Building 5 (WTC 5) was a 9 story office building located on the northeast corner of the World Trade Center Plaza. The collapse of WTC 1 caused damage to WTC 5 and started fires in it (McAllister 2002). The uncontrolled fires resulted in complete burnout of most floors and partial collapse of four floors. The building was steel frame construction with field-bolted connections between floor beams and column tree assemblies. Failure of large sections of floor, in areas not damaged by falling debris from WTC 1, resulted from bolt tear-out at these connections as a result of the uncontrolled fires (Figure 8–14). Photographs of two recovered samples of floor beams (Figure 8–15) show how the field bolts tore out from the beam web weakened by the fires (McAllister 2002).
338 NIST NCSTAR 1-9, WTC Investigation

see: https://www.metabunk.org/threads/critical-errors-and-omissions-in-wtc7-report-uncovered.2332/page-12#post-69630
 
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You are quoting from the summary yet Mick explained NCSTAR 1-9 "Structural Fire Response and Probable Collapse Sequence of World Trade Center Building 7" is the comprehensive report on the collapse

From NCSTAR 1-A -
"Federal Building and Fire Safety Investigation of the World Trade Center Disaster
Final Report on the Collapse of World Trade Center Building 7
"

page 22

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.
 
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Actually NIST says the first girders to fail were the 81-26 girders on floors 13 and 14, at 3.5 hr (in Case B, which is what was carried forward to LSDYNA)

Mick, you are quoting from reports of a computer analysis, are you aware of this? rep seems not to be.
 
From NCSTAR 1-A
From NCSTAR 1-A -
"Federal Building and Fire Safety Investigation of the World Trade Center Disaster
Final Report on the Collapse of World Trade Center Building 7
".

and Mick explained:
  • 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

This is from NCSTAR 1-9:
8.10 SUMMARY

The leading hypothesis for the initiation of the collapse of WTC 7 involved:

Initial local fire-induced floor failures initiating in the tenant floors,

• At least one long unsupported column at the lower floors,

• Buckling of a critical column (the initiating event), which supported a large-span floor bay,

• An initial local failure that brought down the interior structure below the east penthouse, and

• Horizontal progression of the failure across the lower floors that resulted in a progressive collapse of the entire structure.

358 NIST NCSTAR 1-9, WTC Investigation



8.2 LEADING COLLAPSE HYPOTHESIS FOR WTC 7

Based on observations and analyses of photographic and videographic records, critical study of the steel framing, and simplified and detailed analyses to investigate possible failure modes that could lead to an initiating event, the following leading collapse hypothesis was identified.

Initial Local Failure for Collapse Initiation

An initial local failure occurred at the lower floors (below Floor 14) of the building due to fire-induced floor failures, leading to buckling of a critical column (the initiating event) which supported a large-span floor bay with an area of about 200 m2 (2,000 ft2).

The leading hypothesis for the failure sequence that characterized the initial local failure was based on fire-induced failure events in the tenant floors. Floor beams, girders, slabs, and connections heated more quickly and to higher temperatures than the columns. Elevated temperatures in the floor elements led to thermal expansion, with or without thermal weakening and sagging, which resulted in failure of floor connections and/or buckling of floor beams. Sufficient floor component failures (connections and/or beams) resulted in at least one unsupported column over multiple floors at the lower floors. This column buckled and led to the initiation of global collapse.

NIST NCSTAR 1-9, WTC Investigation 323

Bottom line is fires caused the collapse, multiple failures occured due to the fires, and you can't disprove that by acting like a single point within the building was a fluke. See:
https://www.metabunk.org/threads/cr...wtc7-report-uncovered.2332/page-12#post-69630
to see that fires caused multiple failures.
 
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and Mick explained:
  • 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.
  • see above
 
I take that as a yes, that you agree that fires caused the collapse. What other conclusion is logical from the thread you asked me to read?
You have very little comprehension of this thread rep. You need to read it. You do not understand when someone is posting about a hypothetical model, using a hypothetical scenario, and when they are talking about the conclusions that NIST reached. Maybe you should start a thread on this and try and learn to discern between the two. For example, Mick's last post above is talking about Case B in LS DYNA simulation. You clearly do not understand that this is the case. I believe Mick does though, and you are totally missing the point that he is making.
Would you like me to start a thread that deals with the LSDYNA and ANSYS finite element analysis studies that were carried out on WTC7 and we could maybe chat about it there? BOTH these models were unable to explicitly model the connection details at column 79 and 81, NIST say because of the element target size (0.15M-0.3M). This means that they actually have little or no bearing on the content of this thread, or the videos being discussed. Let me know if you want to discuss the FEA models elsewhere, I would be happy to try and help you through it as best I can.
 
That's from your first post to this thread which you are worried about being "derailed." If you don't want to mislead people then you should start your videos by saying that the evidence is that fires caused the collapse. That would certainly improve your video because otherwise it could mislead people into not understanding that fires caused the collapse. But since you were unwilling to give a simple one word answer to my question if you agree that fires caused the collapse, it doesn't appear that you are "happy to discuss the information openly and honestly."
The videos are about the veracity of NISTs collapse hypothesis.
I also referred to a specific point in your video where I explained: "Tangled Webs NIST and WTC7 @ 4:31 the video deceptively asks people to compare WTC5 to WTC7 and it gives the false impression that no steel failed and collapsed within WTC5
The video makes a comparison between wtc5 and wtc7, it shows fires in both buildings and it shows both buildings after the fires. You can draw your own conclusions from the images presented. You said this already and I responded, if you didn't like the answer that you got, then there's little point in discussing it further.
I also have said I would discuss the information with you in a private or a public forum, you have declined, so we will just agree to disagree on this.
Seeing as you are fond of 'one word answers' try giving me one to this question. Did NIST blame thermal expansion of floor beams to the east of column 79 for pushing the girder spanning columns 44 and 79 off its seat?
 
Okay, I have had a brainwave that may be a satisfactory compromise for the 'initiating event' controversy that has dogged this thread. In reverse order of occurrence..................
We could call the column buckling 'the initiating event'.
We could call the girder failing the 'pre-initiating event'
And we could then refer to the thermally expanding beams to the east the 'event required to facilitate the pre-intiating and initiating event'.
Sound good? ;)
 
Okay, I have had a brainwave that may be a satisfactory compromise for the 'initiating event' controversy that has dogged this thread. In reverse order of occurrence..................
We could call the column buckling 'the initiating event'.
We could call the girder failing the 'pre-initiating event'
And we could then refer to the thermally expanding beams to the east the 'event required to facilitate the pre-intiating and initiating event'.
Sound good? ;)

No. Because arbitrarily labeling 79-44 "failing" as a "pre-initiating event" is imposing your own conclusions on the discussion.

Let's avoid confusion entirely, and instead just describe what is in the NIST hypothesis.
Call the columns buckling "the column buckling"
Call the girder failing by whatever NIST describe as happening to the girder.

And don't ignore everything else that happened before the column buckled. Yes, the girder was considered to be failed before the column bucked. But that does not mean the girder fell down, causing all the other floors to fall. NIST does not claim that, you do. NIST's simulations do not show that, you even put up a video that demonstrates that the simulations do not show that.

So why are you continuing to insist the girder fell and triggered the floor collapse?
 
I decided to go back to the start of this thread after this last post from Jazzy to see how we got to such a juvenile point. Fascinating really. At the start, much energy is expended attempting to disprove gerry's original information about stiffeners. As it was gradually accepted that they should have been included in NIST's drawings and modelling, the thread moved to suggest that stiffeners would make no difference anyway. When it was shown that they would have a massive difference, a move to attack the professionals saying that was seen. A demand was made to know the names of others concurring, and requiring to be informed of the quotes from those people. Having reached the point where gerry's original input was in danger of being conceded the only recourse was to look for an escape route. That was attempted by denying that the girder both dropped from its seat and also that it was the initiating event. Much heel digging in was then seen which required them to totally ignore NIST's own words in all their reports and presentations. That went on for some time until once again danger of conceding loomed. Another escape tunnel was required. That was found in the shape of a protracted debate on the meaning of 'initiation'. Whether 'floor' falling meant the girder supporting that floor fell or not. Strong support in the form of 'appeal to authority' from NIST, using spin, to re-name the real inititing event of the girder and floor system dropping from 13 to 12 so that people could claim that the buckled column was the initiating event thus avoiding having to concede NIST's own words quite specifically saying many times that the girder was pushed off its seat. When danger loomed yet again the old favourite of 'lets debate theoretical temperatures' ploy was pulled from the box of debunker tricks. You guys would have made excellent theologians when debating how many angels can dance on a pinhead was all the vogue.
And there we have it. If you can stand the pain go and re-read Jazzy's last entry and you will get my gist.
 
No. Because arbitrarily labeling 79-44 "failing" as a "pre-initiating event" is imposing your own conclusions on the discussion.

Let's avoid confusion entirely, and instead just describe what is in the NIST hypothesis.
Call the columns buckling "the column buckling"
Call the girder failing by whatever NIST describe as happening to the girder.

And don't ignore everything else that happened before the column buckled. Yes, the girder was considered to be failed before the column bucked. But that does not mean the girder fell down, causing all the other floors to fall. NIST does not claim that, you do. NIST's simulations do not show that, you even put up a video that demonstrates that the simulations do not show that.

So why are you continuing to insist the girder fell and triggered the floor collapse?

Because that is what NIST said. Have you not seen and understood the visual and written information from them saying that?

Its not gerry insisting that it was pushed off its seat. In point of fact it was that statement from NIST that began his entire investigation to see if that was possible. And guess what, that is the basis of this entire thread.

And if it was pushed off its seat then all the beams attached to it together with all the concrete still there would fall down with it.
 
Mick, you are quoting from reports of a computer analysis, are you aware of this? rep seems not to be.

As opposed to what?

Surely your assertion that 79-44 failed is also based on the computer analysis? Or is there something else?
 
Because that is what NIST said. Have you not seen and understood the visual and written information from them saying that?

Its not gerry insisting that it was pushed off its seat. In point of fact it was that statement from NIST that began his entire investigation to see if that was possible. And guess what, that is the basis of this entire thread.

And if it was pushed off its seat then all the beams attached to it together with all the concrete still there would fall down with it.

And yet several other girders were also pushed off their seats. And several sections of floor fell where no girders were unseated. And in NISTs own simulation of what happened, the girder you are referring to did not fall in any way that contributed significantly - in fact it seems to have been rocked off its seat by a combination of buckling, and the floor above it collapsing.
 
And yet several other girders were also pushed off their seats. And several sections of floor fell where no girders were unseated. And in NISTs own simulation of what happened, the girder you are referring to did not fall in any way that contributed significantly - in fact it seems to have been rocked off its seat by a combination of buckling, and the floor above it collapsing.

I must apologise. I mistakenly thought that you preferred to cling to the written words of NIST in their reports. My bad. I now see that we must take much more regard of simulated computer models based on input that we are not allowed to check.

And which bears no resemblance to the written word. you see my difficulty ? I was confused as to which of their cliams to accept. But of course you don;t have such a difficulty. You can accept eother version. Whichever version matches your chosen argument at any one time.
 
I decided to go back to the start of this thread after this last post from Jazzy to see how we got to such a juvenile point. Fascinating really. At the start, much energy is expended attempting to disprove gerry's original information about stiffeners. As it was gradually accepted that they should have been included in NIST's drawings and modelling, the thread moved to suggest that stiffeners would make no difference anyway. When it was shown that they would have a massive difference, a move to attack the professionals saying that was seen. A demand was made to know the names of others concurring, and requiring to be informed of the quotes from those people. Having reached the point where gerry's original input was in danger of being conceded the only recourse was to look for an escape route. That was attempted by denying that the girder both dropped from its seat and also that it was the initiating event. Much heel digging in was then seen which required them to totally ignore NIST's own words in all their reports and presentations. That went on for some time until once again danger of conceding loomed. Another escape tunnel was required. That was found in the shape of a protracted debate on the meaning of 'initiation'. Whether 'floor' falling meant the girder supporting that floor fell or not. Strong support in the form of 'appeal to authority' from NIST, using spin, to re-name the real inititing event of the girder and floor system dropping from 13 to 12 so that people could claim that the buckled column was the initiating event thus avoiding having to concede NIST's own words quite specifically saying many times that the girder was pushed off its seat. When danger loomed yet again the old favourite of 'lets debate theoretical temperatures' ploy was pulled from the box of debunker tricks. You guys would have made excellent theologians when debating how many angels can dance on a pinhead was all the vogue.
And there we have it. If you can stand the pain go and re-read Jazzy's last entry and you will get my gist.

The turning point for me was viewing this video


It shows that G79-44 (in green) did not trigger anything, and in fact the video starts at the point where the floor above it has fallen onto it, and the girder is in place, just buckled or bowed.

I though "that's very odd, I thought that the girder falling was the initiating event". So I decided to read 1-9-Structural again, and I realized that they did not. It's been a huge misrepresentation. Sure they describe it as failed, but they also describe a lot of other girder and beams as failed, including the matching girder to the south, which failed around 30 minutes earlier:


(not to mention all the beams that had "loss of vertical support")

At which point I realized this entire argument about the stiffener plates has no significant impact on NISTs description of what happened.
 
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I must apologise. I mistakenly thought that you preferred to cling to the written words of NIST in their reports. My bad. I now see that we must take much more regard of simulated computer models based on input that we are not allowed to check.

And which bears no resemblance to the written word. you see my difficulty ? I was confused as to which of their cliams to accept. But of course you don;t have such a difficulty. You can accept eother version. Whichever version matches your chosen argument at any one time.

How does the report differ from the models exactly?

I'm feeling that you both have this super fixed idea that G44-77 was supposed to come crashing down, triggering massive floor collapses.

But that is not what NIST claim. They don't claim that ANYWHERE. They most they say is that it was pushed off its seat, leading to lack of vertical support. But that that lack of vertical support is just what happened to the entire eastern side of the building on multiple floors, including floors ABOVE that girder.
 
How does the report differ from the models exactly?

I'm feeling that you both have this super fixed idea that G44-77 was supposed to come crashing down, triggering massive floor collapses.

But that is not what NIST claim. They don't claim that ANYWHERE. They most they say is that it was pushed off its seat, leading to lack of vertical support. But that that lack of vertical support is just what happened to the entire eastern side of the building on multiple floors, including floors ABOVE that girder.


How can you find it so very easy to ignore NIST's own contention as here in the final report :-

"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. 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

Why do you continue to claim that NIST didn't say that ? Why do you say such things as this :- " I'm feeling that you both have this super fixed idea that G44-77 was supposed to come crashing down, triggering massive floor collapses."

NIST said that - not gerry. Note the words in blue above.

I will summarise the sequence.

NIST said " the floor beams to the east side of the building expanded enough that they pushed the girder connecting
Columns 79 and 44 to the west on the 13th floor".
NIST said " This movement was enough for the girder to walk off of its support at Column 79".
NIST said " 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."
NIST said " This left Column 79 with insufficient lateral support, and as a consequence, the column
buckled eastward".


Look for the key words above. " beams expanded - girder pushed - girder walk off - cascade of floor failures - column buckled.

Its a sequence that has a beginning and a conclusion. Or initiation leading to result.

You really do begin to back yourself into a corner by denying this.

 
I decided to go back to the start of this thread after this last post from Jazzy to see how we got to such a juvenile point. Fascinating really. At the start, much energy is expended attempting to disprove gerry's original information about stiffeners.

It's a process but Gerry has basically been successful in shifting things around a bit. Just my opinion on it. Attempts to move the goal posts/specifications represents a score, as far as I'm concerned.

Interesting contrast:
My point is that while it possibly invalidates this particular initiating event hypothesis, it does not therefore invalidate the collapse of the building - unless you claim that this is the only possible initiating event.

But when I first got here and asked Mick about possible falsifications he wrote that basically anything that didn't fit the NIST report would act as a falsification of his theory on WTC 7 and lead him to "possibly" start considering the evidence for other theories instead of going into debunking or "anti-theory" mode on everything but NIST.

"...the numbers that would make me start to suspect that WTC7 was a controlled demolition would basically be anything that does not fit the NIST report."

"...the obvious inference is that the fires caused the collapse. If we then read the NIST report we see lots of analysis of the extent of the fire, and the potential damage to connections and beams, comparisons to other building fires, and analysis of the sequence of the collapse. All of that fits the theory that the fire caused the collapse.

But you come along and say "no no, exploding donuts, lol"."

Given that specification, if the NIST report is falsified then other possibilities, scenarios, simulations and so forth should not be invented in order to avoid a comprehensive investigation. Instead, a possible falsification should begin the process of "....start to suspect..." that could lead to a real, comprehensive investigation.
 
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At the start, much energy is expended attempting to disprove gerry's original information about stiffeners. As it was gradually accepted that they should have been included in NIST's drawings and modelling,

Where is the evidence it was not used in the modeling? Isn't it the case that NIST knew about it and they were just presenting images with more details shown for Column 44 but that was just explaining illustrations in the report, not the model they used?

8.7.5 Seats Used for Floor System Connections

Floor beams and girders that framed into exterior columns, and in some instances, girders that framed into interior columns, had seated connections. For example, the girder that framed between interior Column 79 and exterior Column 44 had such connections at both ends.

Seat connections to exterior columns where the floor beam framing was perpendicular to the exterior moment frame were as shown in Figure 8–20. Where the floor beam framed into an exterior column at a skew angle, the seat angle was replaced by a plate. Figure 8–21 shows the seat connection at Column 79 that supported the girder spanning to Column 44 on the exterior. The details of the connections of the other two girders that framed into Column 79 are not shown.

In a seated connection, the beam or girder was supported by the seat, which was welded to the column. Bolts were installed that fasten the beam or girder to the seat for erection purposes. These erection bolts did not carry any gravity load; rather, they were installed to insure that the beam or girder was held in place during erection. NIST found no evidence that the girders or beams in WTC 7 were welded to the seats. In a similar way, an angle or plate was bolted to the top flange to prevent the beam or girder from twisting, but there was little restraint to bending in the plane of the beam.

348 NIST NCSTAR 1-9, WTC Investigation

Consider the girder that spanned between Column 79 on the interior of the building and Column 44 on the exterior. Thermal expansion of this girder would have loaded the erection bolts in shear, since (1) there were no shear studs anchoring the girder to the slab (and thereby restraining elongation), and (2) the columns were prevented from lateral movement because they were embedded in the floor slabs which had considerable in-plane stiffness. Additionally, the expansion of floor beams that framed into this girder, because the framing was asymmetrical, tended to add additional shear load to the erection bolts. The combination of these two shear loads could have failed the bolts in shear. If the erection bolts were to fail, then there would be no positive attachment preventing the girder from being pushed off the seat.

NIST NCSTAR 1-9, WTC Investigation 349
 
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Where is the evidence it was used in the modeling?
Because NIST refers to it, they just were explaining that for the particular illustration "Figure 8-21": "The details of the connections of the other two girders that framed into Column 79 are not shown." But you can see details in Figure 8-20
 
How can you find it so very easy to ignore NIST's own contention as here in the final report :-

"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. 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

Why do you continue to claim that NIST didn't say that ? Why do you say such things as this :- " I'm feeling that you both have this super fixed idea that G44-77 was supposed to come crashing down, triggering massive floor collapses."

NIST said that - not gerry. Note the words in blue above.

I will summarise the sequence.

NIST said " the floor beams to the east side of the building expanded enough that they pushed the girder connecting
Columns 79 and 44 to the west on the 13th floor".
NIST said " This movement was enough for the girder to walk off of its support at Column 79".
NIST said " 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."
NIST said " This left Column 79 with insufficient lateral support, and as a consequence, the column
buckled eastward".


Look for the key words above. " beams expanded - girder pushed - girder walk off - cascade of floor failures - column buckled.

Its a sequence that has a beginning and a conclusion. Or initiation leading to result.

You really do begin to back yourself into a corner by denying this.

I'm not denying it. However nowhere in that does it say that the girder fell off its seat to the west. And you totally ignore the much larger "other local fire-induced damage".

And again you are quoting from the summary, and ignoring the full report.
 
Because NIST refers to it, they just were explaining that for the particular illustration "Figure 8-21": "The details of the connections of the other two girders that framed into Column 79 are not shown." But you can see details in Figure 8-20

That argument if fallacious.

By that line of reasoning, the omission of stiffeners elsewhere in the report, as demonstrated by Gerry, also proves that they were not used in the model.

  • So I ask again, where is the evidence it was used in the modeling?
 
Where is the evidence it was not used in the modeling? Isn't it the case that NIST knew about it and they were just presenting images with more details shown for Column 44 but that was just explaining illustrations in the report, not the model they used?

8.7.5 Seats Used for Floor System Connections

Floor beams and girders that framed into exterior columns, and in some instances, girders that framed into interior columns, had seated connections. For example, the girder that framed between interior Column 79 and exterior Column 44 had such connections at both ends.

Seat connections to exterior columns where the floor beam framing was perpendicular to the exterior moment frame were as shown in Figure 8–20. Where the floor beam framed into an exterior column at a skew angle, the seat angle was replaced by a plate. Figure 8–21 shows the seat connection at Column 79 that supported the girder spanning to Column 44 on the exterior. The details of the connections of the other two girders that framed into Column 79 are not shown.

In a seated connection, the beam or girder was supported by the seat, which was welded to the column. Bolts were installed that fasten the beam or girder to the seat for erection purposes. These erection bolts did not carry any gravity load; rather, they were installed to insure that the beam or girder was held in place during erection. NIST found no evidence that the girders or beams in WTC 7 were welded to the seats. In a similar way, an angle or plate was bolted to the top flange to prevent the beam or girder from twisting, but there was little restraint to bending in the plane of the beam.

348 NIST NCSTAR 1-9, WTC Investigation

Consider the girder that spanned between Column 79 on the interior of the building and Column 44 on the exterior. Thermal expansion of this girder would have loaded the erection bolts in shear, since (1) there were no shear studs anchoring the girder to the slab (and thereby restraining elongation), and (2) the columns were prevented from lateral movement because they were embedded in the floor slabs which had considerable in-plane stiffness. Additionally, the expansion of floor beams that framed into this girder, because the framing was asymmetrical, tended to add additional shear load to the erection bolts. The combination of these two shear loads could have failed the bolts in shear. If the erection bolts were to fail, then there would be no positive attachment preventing the girder from being pushed off the seat.

NIST NCSTAR 1-9, WTC Investigation 349


You really are clutching at straws now. Notice the disclaimer on those drawings? ( Based on fabrication shop drawings )

At risk of being blunt - These arn't real fabrication drawings. They are 'based' on real drawings. They are not to scale. The don't show the stiffeners on the girder. They are illustrations. But of course you know that.

Can you think of a reason why they took the trouble to design and draw illustrations ? Wouldn't it have been easier to cut/paste the real drawings ? But - hang on- that would have shown the real elements there and real dimensions. Hmmm.

But your demand for evidence that the real elements and dimensions were not used in the modelling is interesting. Many people have been demanding that information from NIST for years. And isn't it strange that the very information you demand in order to satisfy your mind is exactly the same as is being sought by others.
 
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I'm not denying it. However nowhere in that does it say that the girder fell off its seat to the west. And you totally ignore the much larger "other local fire-induced damage".

And again you are quoting from the summary, and ignoring the full report.

lol what part of 'pushed off its seat by expansion' is hard to grasp ?
]
And last time I looked a 'push' by the beams would be towards the West.
 
This from the full 1-9 Structural, page 611 (pdf 677)

11. Initial Local Failure for Collapse Initiation. The simple shear connection between Column 79
and the girder that spanned the distance to the north face (to Column 44) failed on Floor 13. The
connection failed due to shearing of erection bolts, caused by lateral thermal expansion of floor
beams supporting the northeast floor system and, to a lesser extent, by the thermal expansion of
the girder connecting Columns 79 and 44. Further thermal expansion of the floor beams pushed
the girder off its seat, which led to the failure of the floor system surrounding Column 79 on
Floor 13. The collapse of Floor 13 onto the floors below—some of which were already
weakened by fires—triggered a cascade of floor failures in the northeast region.
This, in turn, led
to loss of lateral support to Column 79 in the east-west direction over nine stories (between Floors
5 and 14). The increase in unsupported length led to the buckling failure of Column 79, which
was the collapse initiation event.
Content from External Source
Again though this is a summary of a much more complex set of events. It's not at all clear how they justify this pushing off leading to the floor system collapse.

More reading required.
 
This from the full 1-9 Structural, page 611 (pdf 677)

11. Initial Local Failure for Collapse Initiation. The simple shear connection between Column 79
and the girder that spanned the distance to the north face (to Column 44) failed on Floor 13. The
connection failed due to shearing of erection bolts, caused by lateral thermal expansion of floor
beams supporting the northeast floor system and, to a lesser extent, by the thermal expansion of
the girder connecting Columns 79 and 44. Further thermal expansion of the floor beams pushed
the girder off its seat, which led to the failure of the floor system surrounding Column 79 on
Floor 13. The collapse of Floor 13 onto the floors below—some of which were already
weakened by fires—triggered a cascade of floor failures in the northeast region.
This, in turn, led
to loss of lateral support to Column 79 in the east-west direction over nine stories (between Floors
5 and 14). The increase in unsupported length led to the buckling failure of Column 79, which
was the collapse initiation event.
Content from External Source
Again though this is a summary of a much more complex set of events. It's not at all clear how they justify this pushing off leading to the floor system collapse.

More reading required.


Did I just hear a penny drop ?
 
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