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Originally posted by ANOK
Yet no steel frame building has ever collapsed from fire...
Originally posted by gavron
Not one single person coming forward to say he helped in this once-in-a-lifetime event? It would be historic...bringing down a still burning multi-story building in a controlled fashion with little to no notice.
Amazing!
Originally posted by gavron
Originally posted by ANOK
Yet no steel frame building has ever collapsed from fire...
Actually, they two structures that were built the same both collapsed in the same fashion. Are there any other buildings in the world that were built like those two structures....that had aircraft fly into them....and caused multi-floor fires?
Originally posted by ANOK
Originally posted by gavron
Originally posted by ANOK
Yet no steel frame building has ever collapsed from fire...
Actually, they two structures that were built the same both collapsed in the same fashion. Are there any other buildings in the world that were built like those two structures....that had aircraft fly into them....and caused multi-floor fires?
The damage to the towers was asymmetrical so it could not have been cause of a symmetrical collapse.
If it was the aircraft damage then the towers should have fell towards that damage as it would be the path of least resistance.
[edit on 4/26/2010 by ANOK]
Originally posted by gavron
Originally posted by jprophet420
The proof from all previously solved incidences points to some sort of assisted demolition.
...but no reason why they would keep it a secret? If, after all, it was to protect the public, and other structures, to bring it down in a controlled fashion, why not just say so?
Not one single person coming forward to say he helped in this once-in-a-lifetime event? It would be historic...bringing down a still burning multi-story building in a controlled fashion with little to no notice.
Amazing!
Originally posted by Joey Canoli
Originally posted by Azp420
So no, I would not say that an equivalent mass supported by a series of these heated, unrestrained for 8 stories columns, would achieve free fall acceleration, as these ductile columns would still provide an amount of resistance needed to not allow the falling mass to reach its maximum acceleration.
Do you agree with the engineering principles discussed here?
www.civil.northwestern.edu...
To arrest the fall, the kinetic energy of the upper
part, which is equal to the potential energy release, would have to
be absorbed by the plastic hinge rotations, i.e., Wp would have to
be larger than Wg . Rather,
Wg /Wp'8.4 (3)
So, even under the most optimistic assumptions by far, the plastic
deformation can dissipate only a small part of the kinetic energy
acquired by the upper part of building.
When the next buckle with its group of plastic hinges forms,
the upper part has already traveled many floors down and has
acquired a much higher kinetic energy; the percentage of the kinetic
energy dissipated plastically is then of the order of 1%.
Originally posted by pteridine
Originally posted by ANOK
Originally posted by gavron
Originally posted by ANOK
Yet no steel frame building has ever collapsed from fire...
Actually, they two structures that were built the same both collapsed in the same fashion. Are there any other buildings in the world that were built like those two structures....that had aircraft fly into them....and caused multi-floor fires?
The damage to the towers was asymmetrical so it could not have been cause of a symmetrical collapse.
If it was the aircraft damage then the towers should have fell towards that damage as it would be the path of least resistance.
[edit on 4/26/2010 by ANOK]
If you watch the collapse videos, you will see the top of the tower tip toward the damage. This assymetrical collapse did occur as the weakened steel failed, which then precipitated the global collapse. Even this collapse was not completely symmetrical as the core columns remained for some seconds after the collapse of the rest of the building. Hence, your requirement that an assymetrical collapse should have occurred is satisfied.
[edit on 4/26/2010 by pteridine]
Originally posted by ANOK
Once again that PDF is using the NIST assumption that a whole block of floors acted as a plunger, which makes the rest of the paper mute.
Originally posted by Azp420
Edit: And I disagree with those engineering principles.
Originally posted by Joey Canoli
Originally posted by Azp420
Edit: And I disagree with those engineering principles.
Obviously, this was about the towers, not 7.
What I'am asking you about is the engineering principles that I specifically quoted.
Namely, will plastic hinges provide rsistance of about 1% or not.
The part of building lying beneath is then impacted again by an even larger mass falling with a greater velocity
Originally posted by Azp420
This is why OS believers try to steer discussion away from the blaring building 7.
Originally posted by Joey Canoli
Originally posted by Azp420
This is why OS believers try to steer discussion away from the blaring building 7.
I'm not doing that.
I'm asking your opinion on the general engineering principles of how much resistance plastic hinges give.
This does in fact tie into 7, b ut I'm trying to get a straight answer out of you on a principle only, and not even trying to debate any other issues at this time.
Originally posted by Azp420
You were the one that challenged my initial post about WTC7 free falling without CD being an impossibility and have failed to back that up.
Originally posted by Azp420
Let's play along and say that NIST have correctly described how thermal expansion has resulted in ONE (according to NIST) column being minimally braced 8 for stories. How did we get to 8 stories of minimally braced or unbraced column?
Why not collapse when we were unrestrained for 5 stories or 6 stories?
When we reach 8 stories the forces acting on the column are probably starting to exceed what the column can support and it fails in a ductile manner (it is steel not concrete). So no, I would not say that an equivalent mass supported by a series of these heated, unrestrained for 8 stories columns, would achieve free fall acceleration, as these ductile columns would still provide an amount of resistance needed to not allow the falling mass to reach its maximum acceleration.
Even if the column which was unrestrained for 8 stories provided no resistance at all, the rest of the columns would have provided huge resistance.
Originally posted by Azp420
I also said that whether or not a single failing column provides any resistance to free fall, the other 47 stories worth of mostly undamaged structure would have most definitely given a significant amount of resistance to free fall.
Originally posted by Azp420
As you keep attempting to side track the discussion on this I'll take it that you cannot find significant flaws in my reasoning or principles.
Originally posted by Joey Canoli
IF.... ~8 stories worth of the 47 story building had columns that were poorly restrained, and IF one accepts the engineering fact that a column failing plastically will give only about 1% resistance to the falling mass, then it follows that IF there is a "freefall" period, then the "freefall" distance should be roughly equal to that 8 story distance. And, that is exactly what's seen.
So what's the beef?
Originally posted by ANOK
The beef is that is one HUUUUUUGE 'IF'...
IF your columns were NOT 'poorly restrained' then what?
But of course you're not willing to except that likely scenario are you?
I thought you debunkers required proof and facts, but you're quite willing to except assumptions when they come from the government or their lackeys.
Originally posted by Azp420
Lol no. In terms of structural collapses they don't get more symmetrical than that. What should have happened when the top section of the tower leaned over as you stated, is that it continued on that trajectory, taking the path of least resistance to the ground, which is not changing course and plowing straight through the rest of the structure. The falling top section that started falling to the side was magically pulled in by some forces that the OS doesn't mention so we should all just forget about them. To paraphrase Bill Hicks, go back to sleep America, your government is in control.