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Is there a legitimate reason to question the official narrative*?

Is there a legitimate reason to question the official narrative?


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Apparently, some here, you included, have adopted that gem of a strategy: "Here, look at this. It proves my point. Case closed."
I've explained the relevance of the video I posted. You asked for an example of cascade failure, I posted one. You didn't seem aware of the relevance of that video, I explained it in detail. I don't see how your "case closed" claim applies there. Maybe you missed my followup explanation?


Were the lab temperatures higher or lower than in the towers, in your opinion?
No idea. Probably lower in some places and higher in other places.


And as the test administrators wrote, the SFRM slowed the rate at which the steel accumulated heat, as well as slowing the rate at which it dissipated that heat. But if steel is already 800C, what purpose is SFRM serving at that time?
Uniformizing the heating rate.

You probably have missed this sentence from a reference you were given:

Recent research indicates that travelling fires are generally likely to be less severe that fires which are assumed to engulf the whole compartment but that it might be possible in some instances for non-uniform heating across a compartment floor to cause a failure mechanism in the structure, which might not occur if uniform temperatures were applied[6].
http://www.steelconstruction.info/Fire_testing#Success_and_failure_in_fire_testing


So you think all that needs to be done is to conduct a test of the same structure without SFRM? I think that's a good idea.
I'm not. You're the one who wants repeatable tests. I'm satisfied with the results. There are so many ways in which SFRM can be missing, it's impossible to know where it was missing and where it didn't spall, and it's impossible to test every possible way that can happen.
 
Tony I think this may be one of CTBUH's critique of NIST, because they said that NIST did not account for thermal contraction after the beams in the burned out areas of the buildings began to cool down. So we had thermal expansion, bowing against the resistance of the perimeters, sagging, then the steel stiffening as it cools down a bit AND shrinking in size while frozen in the sagged position. That pulled the buildings inward in ways not fully explained by the NIST Report, if I understood their critique correctly.

You are saying the inward bowing occurred when the trusses cooled down. That might be a little hard considering that there were fires on the south side of the building at the time of the collapse.

Additionally, your theory requires the same amount of outward deformation of the columns due to thermal expansion of the trusses and that would be somewhat minimal as the trusses would not be very capable in compression.

I don't think you have a winner here Chris, but nice try.
 
The reality has to be that the inward bowing occurred when the core dropped and pulled on the exterior through the floors. That is the only mechanism that works.

The problem is that the core drops right before the exterior, so there is no time for the exterior to be bowed inward minutes beforehand on the south face of the North Tower.

They say there is a photo of this occurring, but strangely no video. I tend to think somebody is blowing smoke about the minutes before collapse inward bowing and it is what is causing the incoherence.
 
You are saying the inward bowing occurred when the trusses cooled down. That might be a little hard considering that there were fires on the south side of the building at the time of the collapse.

Additionally, your theory requires the same amount of outward deformation of the columns due to thermal expansion of the trusses and that would be somewhat minimal as the trusses would not be very capable in compression.

I don't think you have a winner here Chris, but nice try.

Wouldn't core bracing failure and.core overload cause column
Pull in as observed?
 
I like "Bold".

Dave

Dave, my hypotheses are viable and match the real evidence.

With your inability to provide a mechanism that matches your theory of minutes before collapse inward bowing and your recent failed claim that brittle fracture could have been responsible for column failure, and that it would eliminate column energy dissipation, you are 0 for 2. This is usually the way it goes when one initially emotionally supports what turns out to be an invalid hypothesis after the actual details are examined.
 
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Wouldn't core bracing failure and.core overload cause column
Pull in as observed?

By core bracing it has to be assumed you mean the core floor beams. If they had failed the core would have collapsed.

This puts us back at when the core failed, which was right before the exterior, not minutes before.

It is also hard to see how the core beams would fail, but that is another issue.
 
The reality has to be that the inward bowing occurred when the core dropped and pulled on the exterior through the floors. That is the only mechanism that works.

The problem is that the core drops right before the exterior, so there is no time for the exterior to be bowed inward minutes beforehand on the south face of the North Tower.

They say there is a photo of this occurring, but strangely no video. I tend to think somebody is blowing smoke about the minutes before collapse inward bowing and it is what is causing the incoherence.

Still Images from the video showed the pull
In, but are of lower resolution than the camera
Photo.
That is why there is no video, also you need to explain,
the hanging floors. Before collapse.
 
By core bracing it has to be assumed you mean the core floor beams. If they had failed the core would have collapsed.

This puts us back at when the core failed, which was right before the exterior, not minutes before.

It is also hard to see how the core beams would fail, but that is another issue.

No I mean the critical bracing in the core,
that failed and allowed the top block to
Move.
It was pointed out to me years ago that
The bracing had to fail first.
 
Still Images from the video showed the pull
In, but are of lower resolution than the camera
Photo.
That is why there is no video, also you need to explain,
the hanging floors. Before collapse.

I have never seen video of the south face of the North Tower pulled inward minutes before the collapse. Logic says it happened when the core failed right before the exterior. The exterior failed somewhat abruptly when it was pulled inward by the core.
 
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The reality has to be that the inward bowing occurred when the core dropped and pulled on the exterior through the floors. That is the only mechanism that works.

The problem is that the core drops right before the exterior, so there is no time for the exterior to be bowed inward minutes beforehand on the south face of the North Tower.

They say there is a photo of this occurring, but strangely no video. I tend to think somebody is blowing smoke about the minutes before collapse inward bowing and it is what is causing the incoherence.

The NIST report is littered with photos of both towers in which the bowing is analysed. You demand video evidence for one particular face of the N tower?

Explain why core-led collapse led to bowing of exterior columns, in both towers, minutes before collapse initiation. No need to refer to NIST models, btw, just explain how your theory lives with this contradiction.
 
No I mean the critical bracing in the core,
that failed and allowed the top block to
Move.
It was pointed out to me years ago that
The bracing had to fail first.

The bracing of the columns in the core was performed by the horizontal floor beams between columns at every story. It sounds like you believe there was diagonal bracing. There wasn't.
 
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Infact there was diagonal bracing on the reinforced
Mechanical floors.
As this photo clearly shows.
http://911research.wtc7.net/talks/wtc/ndocs/wtc1_core.jpg

Yes, there was on the mechanical floors but that situation only existed in a small percentage of the structure and would not have had any effect on where the collapse occurred at the 98th floor in the North Tower. The closest mechanical floors were at least ten stories above and about 20 stories below.
 
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Yes, there was on the mechanical floors but that situation only existed in a small percentage of the structure and would not have had any effect on where the collapse occurred at the 98th floor in the North Tower. The closest mechanical floors were at least ten stories above and about 20 stories below.

Agreed, but as Thomas Edgars pointed out to
me disunity of the core and bracing floor beams has to
occur for the top block to tilt.
Such elastic stress then induces weld failure
in the core and the core collapses.
 
Agreed, but as Thomas Edgars pointed out to
me disunity of the core and bracing floor beams has to
occur for the top block to tilt.
Such elastic stress then induces weld failure
in the core and the core collapses.

The top block didn't tilt until two to three stories into the collapse of the North Tower. At that point there would have been a couple of stories of disunity between the core's columns and its floor beams.
 
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The top block didn't tilt until two to three stories into the collapse of the North Tower. At that point there would have been a couple of stories of disunity between the core's columns and its floor beams.

Exactly and the elastic stress produced would pop
The welds that were welded in the core every 36 feet.
 

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