How Buckling Led to "Free Fall" acceleration for part of WTC7's Collapse.

Landru

Moderator
Staff member
Bentham, you seem to be so pre-occupied with saying everything is too complex to figure out, that you failed to realize that I said the severe deformation of the east wall exterior columns would have to occur in a natural scenario when the east interior comes down.

The NIST model shows this deformation because they are pretending it is natural and removing the east interior. In reality, the east interior is not gone and that is why we don't see the exterior deformation as shown in the NIST model. I am speaking of the buckling of the columns at the top in their model, which Mick didn't seem to think could happen as he thought the fact that it was a tube would make a difference. I explained to him that the tube was quite wide and the north and south walls would not have much of an effect on most of the columns of the east wall.

The lack of east exterior wall deformation high in the building in the real collapse is because the east side interior did not collapse the way NIST claims. That is a fairy tale and the structural behavior proves it. I haven't seen anyone who supports the NIST WTC 7 report conclusions have an answer for it.

I also want to complain about how long it takes for my posts to appear. The last one took about 12 hours. I can't deal with that and then respond quickly. This site was not like that before and this large wait time is a real drag on the discussion.
You have been placed in moderation due to excessive off topic posts.
 

Oystein

Senior Member
...
The lack of east exterior wall deformation high in the building in the real collapse is because the east side interior did not collapse the way NIST claims. ...
Are you sure you talk about the east wall? Not the eastern third of the north wall?
I am asking because I am not aware of any video showing the east wall clearly during collapse. Only one I am aware of that shows east wall at all is this:

 

benthamitemetric

Senior Member
Bentham, you seem to be so pre-occupied with saying everything is too complex to figure out, that you failed to realize that I said the severe deformation of the east wall exterior columns would have to occur in a natural scenario when the east interior comes down.

The NIST model shows this deformation because they are pretending it is natural and removing the east interior. In reality, the east interior is not gone and that is why we don't see the exterior deformation as shown in the NIST model. I am speaking of the buckling of the columns at the top in their model, which Mick didn't seem to think could happen as he thought the fact that it was a tube would make a difference. I explained to him that the tube was quite wide and the north and south walls would not have much of an effect on most of the columns of the east wall.

The lack of east exterior wall deformation high in the building in the real collapse is because the east side interior did not collapse the way NIST claims. That is a fairy tale and the structural behavior proves it. I haven't seen anyone who supports the NIST WTC 7 report conclusions have an answer for it.
Do you have any video that shows the east wall of the building during the collapse? I'm not aware of any. Regardless, your claims about how it could or couldn't have deformed are, again, mere bare assertions. In your previous post re the modeling you did, you said you only modeled the northern wall and not the east wall, so it seems unlikely that you can even pretend to have a basis for these particular bare assertions.

And the NIST isn't "pretending" anything with its model. It's a global model based on certain clearly-stated assumptions and simplifications that follows from the output from the ANSYS model, which also was based on certain clearly-stated assumptions and simplifications. You will never have a computer model that is not based on assumptions and simplifications. The assumptions are necessary due all of the unknown variables re the condition of the building and the simplifications are necessary because no computer model can account for everything in such a complex event. There is no reasonable expectation that any computer model could produce an exact collapse visualization that matched reality given such assumptions and simplifications, and it makes zero sense to pretend that, because NIST's model (predictably) does not perfectly match reality, that all of your bare assertions re the collapse in reality needing to be caused by a controlled demolition therefore follow.

And you are still avoiding actually defining your criteria for how much the upper portion of the northern wall would have to deform in any non-controlled demolition collapse. You are making claims based on such criteria, so you should be able to articulate them.
 

Oystein

Senior Member
...
And you are still avoiding actually defining your criteria for how much the upper portion of the northern wall would have to deform in any non-controlled demolition collapse. ...
Tony has also been avoiding the problem of the EPH collapse - in his view, it is unconnected to the global collapse (affecting only a couple of top storeys), which is silly on its face.
 

Tony Szamboti

Active Member
Are you sure you talk about the east wall? Not the eastern third of the north wall?
I am asking because I am not aware of any video showing the east wall clearly during collapse. Only one I am aware of that shows east wall at all is this:

Oy and Bentham, two birds with one proverbial stone here. You can see the east wall in the actual collapse in the video I posted in post #74. Here it is again for your convenience Source: https://www.youtube.com/watch?v=LMeXKNWcbew

There is no buckling up high like there should be if the east side interior had collapsed first and there is in NIST's inaccurate model.
 
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Tony Szamboti

Active Member
Do you have any video that shows the east wall of the building during the collapse? I'm not aware of any. Regardless, your claims about how it could or couldn't have deformed are, again, mere bare assertions. In your previous post re the modeling you did, you said you only modeled the northern wall and not the east wall, so it seems unlikely that you can even pretend to have a basis for these particular bare assertions.

And the NIST isn't "pretending" anything with its model. It's a global model based on certain clearly-stated assumptions and simplifications that follows from the output from the ANSYS model, which also was based on certain clearly-stated assumptions and simplifications. You will never have a computer model that is not based on assumptions and simplifications. The assumptions are necessary due all of the unknown variables re the condition of the building and the simplifications are necessary because no computer model can account for everything in such a complex event. There is no reasonable expectation that any computer model could produce an exact collapse visualization that matched reality given such assumptions and simplifications, and it makes zero sense to pretend that, because NIST's model (predictably) does not perfectly match reality, that all of your bare assertions re the collapse in reality needing to be caused by a controlled demolition therefore follow.

And you are still avoiding actually defining your criteria for how much the upper portion of the northern wall would have to deform in any non-controlled demolition collapse. You are making claims based on such criteria, so you should be able to articulate them.
Of course, NIST is pretending. Their model does not replicate a very large part of the beginning of the collapse in that there is no severe deformation of the east exterior wall in the real collapse and there is in theirs. That's because they took out the whole east side interior, but the structural behavior of the real building shows that could not have happened. Call making things up whatever you like, but that is just what the NIST WTC 7 report is doing. Your objections to that reality have no merit. The actual video shows no deformation of the east wall and everyone can see there isn't. Goodnight. I don't have all night to spend with those who don't even want to admit to a reality in front of their faces. Let me know when you can do so.
 

Redwood

Active Member
Are you sure you talk about the east wall? Not the eastern third of the north wall?
I am asking because I am not aware of any video showing the east wall clearly during collapse. Only one I am aware of that shows east wall at all is this:

This is the video that quite clearly shows a perimeter column falling long after most of WTC 7 has collapsed. How do Truthers deal with that?
 

Landru

Moderator
Staff member
Of course, NIST is pretending. Their model does not replicate a very large part of the beginning of the collapse in that there is no severe deformation of the east exterior wall in the real collapse and there is in theirs. That's because they took out the whole east side interior, but the structural behavior of the real building shows that could not have happened. Call making things up whatever you like, but that is just what the NIST WTC 7 report is doing. Your objections to that reality have no merit. The actual video shows no deformation of the east wall and everyone can see there isn't. Goodnight. I don't have all night to spend with those who don't even want to admit to a reality in front of their faces. Let me know when you can do so.
There are serious questions being asked of you that you are not answering. This is one of the reasons you're in moderation.
 

Oystein

Senior Member
Oy and Bentham, two birds with one proverbial stone here. You can see the east wall in the actual collapse in the video I posted in post #74. Here it is again for your convenience Source: https://www.youtube.com/watch?v=LMeXKNWcbew

There is no buckling up high like there should be if the east side interior had collapsed first and there is in NIST's inaccurate model.
Uhm ... *baffled* ... Tony? No! What you say is FALSE and the exact opposite is true:

You can NOT see the east wall in the actual collapse in the video you posted in post #74. You can only see the north wall.
 

benthamitemetric

Senior Member
Uhm ... *baffled* ... Tony? No! What you say is FALSE and the exact opposite is true:

You can NOT see the east wall in the actual collapse in the video you posted in post #74. You can only see the north wall.
Indeed. Don't even know what to say to this. Is it possible that after 8+ years talking about this, AE911Truth's most vocal mechanical engineer does not actually know the shape and orientation of WTC7?
 

Tony Szamboti

Active Member
Uhm ... *baffled* ... Tony? No! What you say is FALSE and the exact opposite is true:

You can NOT see the east wall in the actual collapse in the video you posted in post #74. You can only see the north wall.
The east exterior wall is certainly visible in the video I posted in post #74. The video was filmed from the northeast.
 

deirdre

Moderator
Staff member
@Tony Szamboti regarding my deletion of your off topic posts... if you wish to 'debate' other members of this thread one-on-one on ANOTHER forum (because we require evidence here) then please private message them.
 

benthamitemetric

Senior Member
The east exterior wall is certainly visible in the video I posted in post #74. The video was filmed from the northeast.
You are mistaken. The video you posted in post 74 is of topmost portion the northern face of the building. The eastern face cannot be seen at all as the eastern wall is at an acute angle to the north wall and runs south-west to the south wall. It is truly amazing that you do not seem to understand the orientation of, and what is visible in, the most famous collapse video of the building.



Oystein separately posted a video wherein you can see a portion of the east wall for a few seconds of the collapse, but you certainly can't see most of the wall for most of the collapse. That video is not a sufficient basis to say much of anything about the overall behavior of the eastern wall. For whatever reason, you cannot seem to bring yourself to acknowledge the glaring limits to what you know and insist on filling in all the gaps with your bare assertions. Maybe step back and re-read my earlier post and actually try to address what I wrote. That might help you break out of these tired old assertions and facilitate an actual evidence-based discussion.

For starters, you are still avoiding actually specifying any actual criteria for which we'd even judge the behavior of the wall that cannot be clearly seen in any video, even if we could see it.
 

benthamitemetric

Senior Member
Just to elaborate on my point above how you cannot see the east face of the building from the camera view provided by Tony in post 74, here is that camera angle via google maps:

upload_2017-10-12_10-13-10.png


upload_2017-10-12_10-54-23.png


The camera was a CBS camera located in midtown at the GM Building on fifth avenue. For argument's sake, I have assumed it was located on the east side of that building. That location is about 4 miles north of where WTC7 stood and about a block to the east. The eastern face of WTC7, however, was angled. You can see the angle of that east face in the foot print of the park where the park abuts W. Broadway just below the southern point of the line I drew (the new WTC7 abandoned the old WTC7's expanded footprint, which let the city extend Greenwich St. and build a new park). There shouldn't be any doubt about this as the video itself is clear, but the map shows also clearly that the camera's vantage point was not far enough to the east to see the eastern face.

It is also worth repeating that none of the camera angles show what was happening to most of any of the building's faces from any side as they are obscured by other buildings in every known piece of footage, so we're only talking about the topmost sections of those faces, in any case.
 
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Oystein

Senior Member
To tighten up benthamitemetric's and my case further, here is the evidence that the video Tony made reference to was indeed shot from the GM building at 767 5th Ave, New York City, NY 10153, USA.

Again, this is Tony's video (I am not embedding again to keep this post a bit shorter): Source: https://www.youtube.com/watch?v=LMeXKNWcbew


It actually has footage from two different cameras. From 0:00 to 0:14 minutes, we het this perspective:

TonyVideo 10s.jpg
and from 0:17 minutes to the end, we get this perspective:
TonyVideo 23s.jpg

In the next two images, I have drawn in the contours of three buildings that are seen in both angles:

TonyVideo 10s augmented.jpg

TonyVideo 23s augmented.jpg

Especially when you lool at the tall building behind WTC7 (which, I assume, is one of the WFC towers, but that's unimportant), it is obvious that the second camera position is to the left (east) of the first position. So that camera has a better chance of capturing the east wall, right?

Now, to determine which camera position that is, let's turn to two truther pages and their repositories:
First, a video posted by Nathan Flach:

From this video, here is a screenshot at 3 seconds - augmented and original:
NathanVideo 03s augmented.jpg

NathanVideo 03s.jpg
The yellow line is just a vertical under the gap between EMP and WMP.
It is obviously the very same camera. Even the marqee is the same. Nathan has this video description:
Secondly, turn to http://www.911conspiracy.tv/7_WTC.html#CBS_GM_Building and scroll down just a little to the third video: "3. CBS GM Building". To the left there is a screenshot, which reproduce here with some contours augmented:
WTC7_CBS_GM_Building_cam augmented.jpg

This screenshot is taken a second or so earlier, before the text marquee "LOWER MANHATTAN VIDEOTAPE" is shown (run the videos to see that I picked the moment for my screenshot when that text first appeared).
Again, obviously the same camera.

911conspiracy.tv has this description of the video (my emphasis):
Shot from the GM building.

The address of the GM Building can be found at Wikipedia: https://en.wikipedia.org/wiki/General_Motors_Building_(Manhattan)

It is 767 5th Ave, New York City, NY 10153, USA, which "is bound by Fifth Avenue and Madison Avenue between 59th Street and 58th Street". And that's next to the SW-corner of Central Park, just as benthamitemetric has it in his map:
https://www.openstreetmap.org/?mlat=40.763889&mlon=-73.9725&zoom=18#map=15/40.7615/-73.9792
 

Attachments

Redwood

Active Member
To tighten up benthamitemetric's and my case further, here is the evidence that the video Tony made reference to was indeed shot from the GM building at 767 5th Ave, New York City, NY 10153, USA.

Again, this is Tony's video (I am not embedding again to keep this post a bit shorter): Source: https://www.youtube.com/watch?v=LMeXKNWcbew


It actually has footage from two different cameras. From 0:00 to 0:14 minutes, we het this perspective:

View attachment 29713
and from 0:17 minutes to the end, we get this perspective:
View attachment 29715

In the next two images, I have drawn in the contours of three buildings that are seen in both angles:

View attachment 29712
View attachment 29714
Especially when you lool at the tall building behind WTC7 (which, I assume, is one of the WFC towers, but that's unimportant), it is obvious that the second camera position is to the left (east) of the first position. So that camera has a better chance of capturing the east wall, right?

Now, to determine which camera position that is, let's turn to two truther pages and their repositories:
First, a video posted by Nathan Flach:

From this video, here is a screenshot at 3 seconds - augmented and original:
View attachment 29710
View attachment 29711
The yellow line is just a vertical under the gap between EMP and WMP.
It is obviously the very same camera. Even the marqee is the same. Nathan has this video description:
Secondly, turn to http://www.911conspiracy.tv/7_WTC.html#CBS_GM_Building and scroll down just a little to the third video: "3. CBS GM Building". To the left there is a screenshot, which reproduce here with some contours augmented:
View attachment 29716
This screenshot is taken a second or so earlier, before the text marquee "LOWER MANHATTAN VIDEOTAPE" is shown (run the videos to see that I picked the moment for my screenshot when that text first appeared).
Again, obviously the same camera.

911conspiracy.tv has this description of the video (my emphasis):
Shot from the GM building.

The address of the GM Building can be found at Wikipedia: https://en.wikipedia.org/wiki/General_Motors_Building_(Manhattan)

It is 767 5th Ave, New York City, NY 10153, USA, which "is bound by Fifth Avenue and Madison Avenue between 59th Street and 58th Street". And that's next to the SW-corner of Central Park, just as benthamitemetric has it in his map:
https://www.openstreetmap.org/?mlat=40.763889&mlon=-73.9725&zoom=18#map=15/40.7615/-73.9792
Just to help: The other camera location was the CNN camera atop 5 Penn Plaza. I once thought that there were only four videos that captured the complete collapse sequence of WTC 7, until I realized there were actually two. (Reading the invaluable NCSTAR 1-9 really helped!) Here's the CNN video: (Source: https://www.youtube.com/watch?v=wqA46_bX5n0(https://www.youtube.com/watch?v=wqA46_bX5n0)
You can tell from the parallax that the CBS and CNN videos are distinct.
 

Tony Szamboti

Active Member
The argument made by some NIST WTC 7 report supporters here, that you can’t see the east wall in video from the north because of the trapezoidal shape, does not obviate the argument about the lack of east exterior column deformation at the top in the actual collapse.

In the NIST model the entire east side exterior starts buckling at the top of the building, as it would if the east interior had collapsed, and it includes columns on the east side of the north wall, which is certainly visible in video. Unfortunately, for these NIST report supporters, that behavior is not observed in the actual collapse, showing the east side interior did not collapse the way NIST claims.

In addition to the lack of deformation of the east side exterior in the actual collapse, there are several other points of evidence that the east penthouse only collapsed into the top of the building and left the east side core columns intact for most of their height. This is why we don't see the east exterior columns buckle at the top of the building in the actual collapse the way they do in the NIST model.

The full argument is actually a closed loop and to try and say you can't see the east wall is not even a partial counter to it. Of course, those trying to make that argument are not engineers and didn't think about it being the east side of the building, which includes the east side of the north wall. They naively thought that if they can show you can't see the actual east wall itself that they had a counter. They don't and their lack of understanding structural behavior shows. Of course, this is what happens when those with less understanding than required try to argue. Eventually, that lack of understanding is exposed.
 
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deirdre

Moderator
Staff member
The full argument is actually a closed loop and to try and say you can't see the east wall is not even a partial counter to it. Of course, those trying to make that argument are not engineers and didn't think about it being the east side of the building, which includes the east side of the north wall. They naively thought that if they can show you can't see the actual east wall itself that they had a counter

Or maybe they were just arguing that your insisting the East wall is what we see in the video was wrong. You can't have a productive discussion if people think they are looking at two completely different things.



Are you sure you talk about the east wall? Not the eastern third of the north wall?
I am asking because I am not aware of any video showing the east wall clearly during collapse. Only one I am aware of that shows east wall at all is this:
and you replied:
upload_2017-10-21_13-24-13.png


then you said:

The east exterior wall is certainly visible in the video I posted in post #74. The video was filmed from the northeast
 

Tony Szamboti

Active Member
Or maybe they were just arguing that your insisting the East wall is what we see in the video was wrong. You can't have a productive discussion if people think they are looking at two completely different things.





and you replied:
View attachment 29847

then you said:
The argument about not being able to see the east wall itself in the video is a moot point. It is the entire east side which should be deforming at the top of the building if the east side interior had actually collapsed the way NIST claims. There is no column buckling at the top of the building as is seen in the NIST model and what would have to have happened if the east side interior had collapsed before the exterior.

The NIST model does not replicate the actual collapse and it is far from it. In fact, the lack of exterior deformation at the top of the building in the real collapse is also an argument against the Arup and Weidlinger analyses, as they also claim the east side interior collapsed first.
 
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Oystein

Senior Member
...to try and say you can't see the east wall is not even a partial counter to it. Of course, those trying to make that argument are not engineers and didn't think about it being the east side of the building, which includes the east side of the north wall. ...
You may want to correct this erroneous statement. As Deirdre already documented, I had immediately responded to your bizarre claim that the video shows the east wall:
Are you sure you talk about the east wall? Not the eastern third of the north wall?
So you see, I, the non-engineer DID "think about it being the east side of the building", and gave you a chance to correct your error.

You now coming back and pretending that you were thinking right and I was thinking wrong about what is and isn't seen in the video is ourageous.

It is very difficult to start a serious debate with you if you insist so stubbornly on making FALSE claims.

I may respond constructively to a post of yours if you manage to not load it with false premises.
 

Tony Szamboti

Active Member
Some here are trying to keep the argument on whether or not you can see the east wall and whether or not I was wrong on that. They are in fact arguing a moot point, with their obvious problem being that they can't address the real issue, which is no deformation of the east side, which would be visible on the east side of the north face in the video.

This shows these debunkers have no argument against what I am saying.
 

Oystein

Senior Member
Some here are trying to keep the argument on whether or not you can see the east wall and whether or not I was wrong on that.
No, Tony, that is FALSE. These two questions were thoroughly settled once and for all nine days ago. Even you are not arguing any longer that you were right.
Once again, you start off a post with a FALSE premise. This behaviour will not get you started on anything. Change it!

They are in fact arguing a moot point,
If this point is moot, why did you bring it up in the first place, why did you insist on it, why did it rile you up so much that you sent me an unsolicited email insulting me?

When, exactly, did this point turn moot in your mind?

with their obvious problem being that they can't address the real issue, which is no deformation of the east side, which would be visible on the east side of the north face in the video.
When I asked you to clarify EXACTLY THAT POINT you acted as if the east wall was visible and as if that point was anything but moot.

This shows these debunkers have no argument against what I am saying.
Whatever.

Try writing posts that are not loaded with FALSE premises, and people might actually address them.
A good start would be to correct gladly your mistakes and own them.
 

Jeffrey Orling

Senior Member
The argument about not being able to see the east wall itself in the video is a moot point. It is the entire east side which should be deforming at the top of the building if the east side interior had actually collapsed the way NIST claims. There is no column buckling at the top of the building as is seen in the NIST model and what would have to have happened if the east side interior had collapsed before the exterior.

The NIST model does not replicate the actual collapse and it is far from it. In fact, the lack of exterior deformation at the top of the building in the real collapse is also an argument against the Arup and Weidlinger analyses, as they also claim the east side interior collapsed first.
The East facade did not buckle... it fell down because the braced frame from ground to floor 7 was pulled inward by the collapse of transfer trusses 1 and 2. the cause of their collapse may have been from mass falling fro, floor 13... I don't buy that... or some failure of the truss system which caused everything above the east side to plunge down... and the failures rapidly propagated westward.

Essentially the bottom if the facade was pulled out from it at floor 7... and this explains the FF for 100 feet.
 

Tony Szamboti

Active Member
The East facade did not buckle... it fell down because the braced frame from ground to floor 7 was pulled inward by the collapse of transfer trusses 1 and 2. the cause of their collapse may have been from mass falling fro, floor 13... I don't buy that... or some failure of the truss system which caused everything above the east side to plunge down... and the failures rapidly propagated westward.

Essentially the bottom if the facade was pulled out from it at floor 7... and this explains the FF for 100 feet.
We know NIST did not get the collapse initiation mechanism right and you believe the failure of two of the transfer trusses where what started it. It sounds like you think they should redo the analysis looking at the transfer trusses. Is that right?
 

Jeffrey Orling

Senior Member
We know NIST did not get the collapse initiation mechanism right and you believe the failure of two of the transfer trusses where what started it. It sounds like you think they should redo the analysis looking at the transfer trusses. Is that right?
Tony... I am not satisfied with the fact that the transfers were mostly ignored. What led to the RELEASE was the failure of those trusses. What caused their failure needs to be determined. I suppose it could have initiated in load transfer region. Or it could have initiated on some floor(s) above them... but the "internal movement" would go unseen from outside. The drop of the EPH in advance of RELEASE tells us something failed below it... and it APPEARS to have dropped right thru the building...as evidenced by the facade showing a wave of distortion as it descends. But we can"t see where the initiating failure was.

I do think this needs ti be determined.

I think perhaps that NIST didn't want to "blame" diesel because the decision to store so much on sight was "political". Office fires are not political.
 

benthamitemetric

Senior Member
So now that we've established that Tony clearly misunderstood the video evidence he cited in support of his claims, is there anything else left to his claims? Not from what I can see. Since we do not know whether the eastern wall behaved in a way consistent with the predictions of NIST simulations, all Tony can point to is that the north eastern corner in reality was more resilient than in the simulation, at least for the first few floors of distance that it fell. What Tony can't tell us is why this discrepancy between NIST's high level simulation, which is clearly and explicitly based on a number of assumptions and simplifications, and reality is at all indicative of a fundamental error in NIST's model. He offers no criteria as to how the building would necessarily behave in a natural collapse scenario and does not at all support his contention that a natural collapse is inconsistent with the observed behavior of the building in reality; he does not even offer any criteria for the contention that the NIST simulation output was materially different from the building in reality, given what can actually be seen in video evidence of the building in reality and all of the clearly and explicitly stated assumptions and simplifications in NIST's model. He acknowledges that the so-called "free fall" period could happen as a result of the outer columns buckling but thinks such mechanism couldn't have happened in reality because the outer columns in the north eastern corner would also necessarily be pulled in a little bit (as they were NISTs simulation) at the time the core collapsed. Even putting aside that Tony misunderstood the video evidence, Tony's whole chain of objections here is tantamount to a (logically tortured) grasping at straws.
 
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benthamitemetric

Senior Member
Tony... I am not satisfied with the fact that the transfers were mostly ignored. What led to the RELEASE was the failure of those trusses. What caused their failure needs to be determined. I suppose it could have initiated in load transfer region. Or it could have initiated on some floor(s) above them... but the "internal movement" would go unseen from outside. The drop of the EPH in advance of RELEASE tells us something failed below it... and it APPEARS to have dropped right thru the building...as evidenced by the facade showing a wave of distortion as it descends. But we can"t see where the initiating failure was.

I do think this needs ti be determined.

I think perhaps that NIST didn't want to "blame" diesel because the decision to store so much on sight was "political". Office fires are not political.
NIST did not ignore the transfer trusses. Here is a paper written by one of the principal authors of the NIST WTC7 report that details how he believed the transfer trusses led to the horizontal failure propagation:

upload_2017-11-4_10-42-2.png



It's not clear from the NIST report itself (or at least I do not recall the NIST report commenting on) exactly what role the transfer trusses played in the horizontal propagation. Clearly, however, NIST considered their role.
 

Mick West

Administrator
Staff member
It's not clear from the NIST report itself (or at least I do not recall the NIST report commenting on) exactly what role the transfer trusses played in the horizontal propagation. Clearly, however, NIST considered their role.
Surely the role would have been apparent in the progression simulation?
 

benthamitemetric

Senior Member
Surely the role would have been apparent in the progression simulation?
I'd assume so, and, in fact, in the link I provided above, Gilsanz and Ng explicitly discuss observing the role the transfer trusses played in NIST's early model of the global collapse. I just didn't recall whether the final NIST WTC7 report also noted NIST's conclusions re the transfer trusses. Looking back at that report now, it seems that NIST does believe the trusses could have played a roll in the horizontal propagation; they just do not provide much in the way of a narrative description of that role. See, e.g., this graphic from NCSTAR 1-9:

upload_2017-11-4_22-52-27.png


Suffice to say, there is a big difference between not providing a narrative account of the exact role of a certain system and not considering the role of that system. In NIST's case, I believe a careful reading of NCSTAR 1-9 and the Gilsanz/Ng article make clear that they did consider the role of the transfer trusses.
 

Jeffrey Orling

Senior Member
Interesting demos... One has to consider the ratio of the OAL unbraced length to the smallest plan dimension of the column. The demo shows the buckling in the small axis... which is obvious to be the one that will drive the direction of the buckling. Bracing adds strength to resist buckling as demo 1 shows. Perhaps you should repeat and remove some of the floors and observe the buckling.

Note in the design of the twin towers core some of the bracing was not framed directly into the web or flange such as the belt girders which were outside the perimeter and cantilevered from the core. Also in both designs the column ends were unrestrained... and that's where the multi story column buckling occurred.
 

Gamolon

New Member
So now the NIST analysis is spot on? Before you were saying it is wrong because it showed a gradual onset.
View attachment 30987

How would that graph vary exactly if there was just a few tons of resistance? Like 1% of the weight?
So if I am reading the graph above correctly, it indicates the following:

1. The data points at 1.5s and 1.75s indicate a slight decrease in velocity from about 10ft/sec to 9ft/sec (deceleration)
2. The data points at 1.75s and 2s indicate an increase in velocity from about 9ft/sec to 19ft/sec (acceleration)
3. The data points 2.25s and 2.5s indicate an increase in velocity from about 25ft/sec to 41ft/sec (acceleration)
4. The data points 4s and 4.25 indicate no increase in velocity which stayed at about 82ft/sec (constant, no acceleration or deceleration)

If so, it would mean that for 1. above, resistance of some sort was met. For 2., we're at free fall or no resistance. For 3. we're at greater than free fall. For 4., we're at a constant rate of descent, no acceleration, no deceleration.

Is this all correct?
 

Jedo

Member
Some physics knowledge to be thrown into this thread regarding

1. the conservation of momentum

There is a very basic law of physics that is being violated by the collapse of this building: the conservation of momentum.
You need to look at conversation of momentum and of energy in conjunction.
There is no conservation of momentum regarding masses in a gravity field for movement perpendicular to the equipotential surfaces (i.e. up or down colloquially speaking). Just think of a ball thrown up in the air: it starts with some upward momentum, it attains zero momentum at the turning point, and it increases constantly its downward momentum until it hits the ground, where the momentum gets reversed again or gets zero, depending on the elastic properties of ground and ball.

There is only conservation of momentum of the total system, which is the combined system of WTC7 and planet Earth. Good luck with that. :p

2. the transparency of air

Honestly, this question puts me in a peculiar position: it's almost equivalent to asking me to find documentation to air being transparent.
Documentation for air being transparent (you have actually to take care of the wavelength of the radiation, but I guess you meant in the visible regime), see any absorption or transmission spectra of the atmosphere or of the pure gases air consists of. ;)

Sorry, i really had to comment on this despite being off-topic, still it is a bunk statement and I debunk it as such. Hope moderators leave it anyway (please! :rolleyes:)
 

Oystein

Senior Member
Some physics knowledge to be thrown into this thread regarding

1. the conservation of momentum





There is no conservation of momentum regarding masses in a gravity field for movement perpendicular to the equipotential surfaces (i.e. up or down colloquially speaking). Just think of a ball thrown up in the air: it starts with some upward momentum, it attains zero momentum at the turning point, and it increases constantly its downward momentum until it hits the ground, where the momentum gets reversed again or gets zero, depending on the elastic properties of ground and ball.

There is only conservation of momentum of the total system, which is the combined system of WTC7 and planet Earth. Good luck with that. :p

...
All true, obviously.

When I commented that consideration of CoM is insufficient, that you also need to think of CoE, I was thinking about a minimum requirement of considerations. A collapse can be viewed as an event with many collisions, resulting in accelerations and velocities, some of which may be observed. The Truther argument that CoM is violated is never made out. In the case of WTC7, I haven't even seen a hint how Truthers would plan on making it out, if they ever tried.

In the case of WTC1+2, there is some limited applicability of "CoM+CoE" when looking at a crude model for the pancaking collapse propagation, where floor slabs are only weakly coupled to planet earth as the mass of many stories impacts one from above: The impact itself is sufficiently short so that gravity does not add significant Momentum, and the column-to-floor connectors were too weak to convey much Momentum or Energy to the columns and thus down to the foundations. It turns out that a simple "CoM+CoE" pancaking model predicts the actual acceleration of the twin tower tops quite nicely: a ~ 2/3 g after a few floors have been impacted. This means that 1/3 of the accrued PE differential was available to break connections, crush concrete and building contents, bend steel. That was, of course, more than enough to make collapse propagation inevitable.

I don't see how a similar model can be constructed for WTC7.
 

John85

Member
This means that 1/3 of the accrued PE differential was available to break connections, crush concrete and building contents, bend steel. That was, of course, more than enough to make collapse propagation inevitable.
Calculations welcomed, if you have evidence to support this claim.
 
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