Why did the WTC columns pull in?

e^n said:
To my utter amazement there is a video showing the south side of the north tower! I didn't think that this existed but apparently it does, this should hopefully convince you realcddeal.

http://www.youtube.com/watch?v=xR4qOo6XY-Y&feature=user
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The antenna seems to wobble a small amount and then go down and then tilts ever so slightly and then comes straight down for quite a distance, and finally completely falls to the side.

This does not disprove the fact that the antenna dropped before the perimeter roofline.
 
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realcddeal said:
This does not disprove the fact that the antenna dropped before the perimeter roofline.
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Referring to contested things as 'facts' is a typical truther tactic. The evidence to support this is a video taken from such an angle that motion of the roofline would be extremely hard to detect compared to videos from different angles. What do you support this claim with?

edit: almost forgot:
realcddeal said:
The temperatures you site are peak temperatures. I don't think anyone would claim peak temperatures exist everywhere in a fire and are certainly not indicative of object temperatures, especially big ones with large thermal capacities and the ability to transfer heat like interconnected steel columns and beams. The link says this straight out.
...
If you haven't yet you might want to take a look at the Cardington fire tests, done on a typical steel framed building.
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I was playing about with some graphing software and I thought i'd try and illustrate how you may be wrong here also:


edit2:
It's quite easy to produce a nice looking graph actually (this is using gnuplot)


Triple edit: The source for these is the Cardington fire tests test #4 (Office fire demonstration)
 
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realcddeal said:
The antenna seems to wobble a small amount and then go down and then tilts ever so slightly and then comes straight down for quite a distance, and finally completely falls to the side.
Click to expand...

The antenna is seen against a background of rising smoke, so without measurements it's very difficult to tell exactly how it's behaving. Come back when you have numbers.

Dave
 
e^n said:
Referring to contested things as 'facts' is a typical truther tactic. The evidence to support this is a video taken from such an angle that motion of the roofline would be extremely hard to detect compared to videos from different angles. What do you support this claim with?

edit: almost forgot:

I was playing about with some graphing software and I thought i'd try and illustrate how you may be wrong here also:
[qimg]http://xs124.xs.to/xs124/08092/temps867.png[/qimg]

edit2:
It's quite easy to produce a nice looking graph actually (this is using gnuplot)
[qimg]http://xs124.xs.to/xs124/08092/temps2520.png[/qimg]

Triple edit: The source for these is the Cardington fire tests test #4 (Office fire demonstration)
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Nice partial job. Now you need to finish the job and do the graphs for the steel beam and column temperatures, from the Cardington tests. Then we can have a discussion.
 
realcddeal said:
Nice partial job. Now you need to finish the job and do the graphs for the steel beam and column temperatures, from the Cardington tests. Then we can have a discussion.
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:rolleyes: Burden of Proof, Tony.

Besides, how about you tell us what temperatures does NIST predict in the structural elements? And then tell us how impossible it is?
 
Mackey: This thread supports that severed core columns would cause at least some perimeter bowing.

Confirm or deny before I include it in my hypothesis please
 
Sizzler said:
Mackey: This thread supports that severed core columns would cause at least some perimeter bowing.

Confirm or deny before I include it in my hypothesis please
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I wondered if you'd forgotten.

Severed core columns that lead to displacement of core structures will lead to perimeter bowing by the mechanism posited in the OP. It is one of many mechanisms that will do that. Severed core columns that do not lead to displacement, on the other hand, may not.
 
R.Mackey said:
I wondered if you'd forgotten.

Severed core columns that lead to displacement of core structures will lead to perimeter bowing by the mechanism posited in the OP. It is one of many mechanisms that will do that. Severed core columns that do not lead to displacement, on the other hand, may not.
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Thanks Mackey:)

ps. why didn't you address this before? You are a hard man to have a conversation with sometimes.
 
Gentlemen, you are missing the point of this thread. We know that the columns bowed very far inwards before collapse. The only way they could have done this is if they were HOT. 500c or 600c would do the trick. The calculations prove this. The conspiracy fantasies of therm*te and explosives will not cause this effect. Core column damage only will not cause any large noticeable bowing and the inward pull cannot be large enough to cause large deflections in cold perimeter columns before the truss-column connections are severed.

Either explain a mechanism that caused the columns to bow in that far (I'd like to see the math with it) or admit that the fire did in fact heat the steel to approximately 600c.
 
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Sizzler said:
Mackey: This thread supports that severed core columns would cause at least some perimeter bowing.

Confirm or deny before I include it in my hypothesis please
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Core column only damage will not cause the perimeter columns to deflect the amount that was observed. The steel needs to be heated to about 600c for the steel to deflect as much as observed.

You cannot ignore the fire and just pretend that the core columns caused ALL the deflection just because the caused some. Be realistic.
 
Yes, I did. I apologize.

Sizzler said:
Mackey: Doesn't his model also demonstrate that core column cutting due to therm?te (assuming proper therm?te cutting devices exist) theoretically could have been the culprit too? I'm pretty sure firgure 3 and 4 support the notion that cut core columns alone, could result in perimeter bowing.
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I don't think so. Some perimeter bowing, yes, but not as much as was observed. NIST basically ran this experiment in the component simulations of NCSTAR1-6 and could not even get close to the observed bowing... Newton's Bit's derivation doesn't include the hat truss action, which will oppose displacement from the cut columns. NIST ran into this difference between its component sims and the global sim, too.

Cut enough and I guess it's possible. There is more than one way to make the perimeter bow. I just don't think there's more than one way that's plausible. Maybe you've got a good idea.
 
R.Mackey said:
Yes, I did. I apologize.



I don't think so. Some perimeter bowing, yes, but not as much as was observed. NIST basically ran this experiment in the component simulations of NCSTAR1-6 and could not even get close to the observed bowing... Newton's Bit's derivation doesn't include the hat truss action, which will oppose displacement from the cut columns. NIST ran into this difference between its component sims and the global sim, too.

Cut enough and I guess it's possible. There is more than one way to make the perimeter bow. I just don't think there's more than one way that's plausible. Maybe you've got a good idea.
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Yes, NIST includes hat truss action in determining that 6kip figure and I took that number from that. And that number seems very reasonable to me.
 
Newtons Bit said:
Core column only damage will not cause the perimeter columns to deflect the amount that was observed. The steel needs to be heated to about 600c for the steel to deflect as much as observed.

You cannot ignore the fire and just pretend that the core columns caused ALL the deflection just because the caused some. Be realistic.
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But if more core columns are cut, that would increase bowing, right?

Also if connections between perimeter and floor trusses were cut, that would increase bowing right?

Given the estimated core damage that NIST reports, I understand what you are saying. But if more and more columns were cut through time, wouldn't bowing occur too?
 
R.Mackey said:
Yes, I did. I apologize.



I don't think so. Some perimeter bowing, yes, but not as much as was observed. NIST basically ran this experiment in the component simulations of NCSTAR1-6 and could not even get close to the observed bowing... Newton's Bit's derivation doesn't include the hat truss action, which will oppose displacement from the cut columns. NIST ran into this difference between its component sims and the global sim, too.

Cut enough and I guess it's possible. There is more than one way to make the perimeter bow. I just don't think there's more than one way that's plausible. Maybe you've got a good idea.
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Right, so if one were to cut MORE columns, it would bow more. Right?
 
Sizzler said:
But if more core columns are cut, that would increase bowing, right?
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It would never result in the columns bowing inwards to the extent seen.

Also if connections between perimeter and floor trusses were cut, that would increase bowing right?
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The connection between the perimeter columns and the floor trusses is what applies to the force to the columns. Sever some on some floors only increases the total load on those of the other floors. This idea still suffers from the fact that the connections have a finite capacity.

Given the estimated core damage that NIST reports, I understand what you are saying. But if more and more columns were cut through time, wouldn't bowing occur too?
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Yes, but not to the extend that is observed. How is it that you can look at a picture like this:
nist1-6D-fig39.JPG


And say that fire is not part of the equation? Why MUST you try to find another explanation (falsely) when this explanation fits all the criteria and all the observed phenomenon?
 
Newtons Bit said:
It would never result in the columns bowing inwards to the extent seen.



The connection between the perimeter columns and the floor trusses is what applies to the force to the columns. Sever some on some floors only increases the total load on those of the other floors. This idea still suffers from the fact that the connections have a finite capacity.



Yes, but not to the extend that is observed. How is it that you can look at a picture like this: [qimg]http://bp0.blogger.com/_-e0bzNzFdXc/R8CFUMUe5eI/AAAAAAAAANs/r8Tb9QuweDQ/s400/nist1-6D-fig39.JPG[/qimg]

And say that fire is not part of the equation? Why MUST you try to find another explanation (falsely) when this explanation fits all the criteria and all the observed phenomenon?
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I accept that fire increased bowing. I just wanted to how cutting more columns would affect bowing.

Thanks:)
 
Sizzler said:
Right, so if one were to cut MORE columns, it would bow more. Right?
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Eh... maybe, maybe not. Cut too many and the core becomes unstable. WTC 2 is interesting in this respect.

Newtons Bit said:
And say that fire is not part of the equation? Why MUST you try to find another explanation (falsely) when this explanation fits all the criteria and all the observed phenomenon?
Click to expand...

I put him up to formulating his own hypothesis, this may be part of the exploration. So blame me if you want. :boxedin:
 
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