What Really Happened on 9/11?

[Gravy]

Hold it, hold it, hold it!
Let's get this straight.
The steel did not get soft enough to deform, or even become pliable, as most people think of it.It did get weaker.

Where do you get off makin' sense around here?
That was a helpful description, even though I don't know a force/displacement curve from my earhole.

 

[ntech]

Uh, I just made a simple correction to someone's misstatement, my friend. You don't seem to have read my other posts here. Perhaps start with this one on the previous page http://www.internationalskeptics.com/forums/showpost.php?p=1551518&postcount=388

Sorry Gravy. I got carried away. ...and to another New Yorker too......

 

[Piggy]

I'm referring to a very detailed hour-long TV documentary examining in great detail exactly what happened from a structural point of view. Can anyone else remember any more details of this programme?

Here's a link to the US site:
http://www.pbs.org/wgbh/nova/wtc/

 

[Rolfe]

Hold it, hold it, hold it!
Let's get this straight.
The steel did not get soft enough to deform, or even become pliable, as most people think of it.It did get weaker. A fine distinction, I know, but let's be as accurate as possible
Take a generic steel. It has a yield stress of 36000psi (2.48x10^8 Pa) at 70 degrees F. Heat it to 500 degrees F, and that value is at 3/4 the original. At 800 degrees F, it is about 1/2.
Stress is Force/area in compression. You also have to add in M*C/I for bending, where C and I are geometry-based values--the shape is important, here.. Ideally, the collumns are in pure axial load--that's the way they are designed.
So now we have 1/2 the strength, plus!!!! steel gets longer as it gets hotter!!!! Amazing physical property, known to everyone except CT'er's. If the heating is symetrical, it all gets longer at the same rate. If not, as was likely the case, things get complex.
The floor trusses got longer (and weaker), trying to push the support collumns. This puts them (the collumns) in bending--they were designed for axial loading. Additionally, the collumns themselves are trying to get longer, while at the same time, getting weaker-both by heating.
It does not take long to fail a beam by restraining the ends (loading them), and heating the beam. You can find the values for Coefficient of thermal expansion (units are in/in/degree F), and calculate the strain (elongation per unit length (in/in)) at any temperature. Look that strain up on a force/displacement curve for your material, and figure the stress. Amazing how fast it goes to failure...

I think that's a bit more detail than Horizon were prepared to take in!

MATTHYS LEVY (Structural Engineer): Steel will lose half its strength by the time it rea, reaches about 500 degrees Centigrade, so that fire caused the steel to soften up. The columns began to soften, buckle, fail.

It's a pity the graphics aren't online. I seem to remember graphics of beams bending, and the ends sliding off the supports, but it's also possible that they were shown becoming longer.

Whatever, it's perfectly clear that the structural integrity of steel is severely compromised way before it gets anywhere near the quoted "melting point". Even without understanding every word of your explanation, I get that. What's so hard?

Rolfe.

 

[hurdygurdy]

It's a pity the graphics aren't online. I seem to remember graphics of beams bending, and the ends sliding off the supports, but it's also possible that they were shown becoming longer.

I finally downloaded a copy of the doc, so maybe I can help here. You mean these graphics?

 

[Rolfe]

Oh, I remember these. Actually, what I was thinking of were schematics with red trusses, but I remember these as well, so yes.

I've just been reading the "Loose Change" thread (man, oh man!) and I see that "Alek" is well aware of that documentary, as he quotes it - but only in support of a probably not entirely accurate assertion that there have been no other comparable examples of steel-famed buildings pancaking. However, he seems completely closed-minded to the explanation put forward when it is advanced from other sources, so I don't expect a look at Horizon would instantly convert him.

Rolfe.

 

[Piggy]

Q: How many conspiracy theorists does it take to change a light bulb?

A: That was no lightbulb, you idiot, it was a squib. You can see it plain as day on the video! I got a guy here with a degree in civil engineering can explain it all to you, if you'll just open your minds. You people are so blind! When are you gonna wake up and SEE THE TRUTH!!!! Oh, you can't. You know why? Cause you think a squib is a light bulb, which is why you can't SEE ANYTHING!!!!!!!!!!!!

 

[RandFan]

Q: How many conspiracy theorists does it take to change a light bulb?

A: That was no lightbulb, you idiot, it was a squib. You can see it plain as day on the video! I got a guy here with a degree in civil engineering can explain it all to you, if you'll just open your minds. You people are so blind! When are you gonna wake up and SEE THE TRUTH!!!! Oh, you can't. You know why? Cause you think a squib is a light bulb, which is why you can't SEE ANYTHING!!!!!!!!!!!!

I liked Piggy. He was just a kid for Ed's sake. He understood the necessity of morality.

 

[delphi_ote]

I liked Piggy. He was just a kid for Ed's sake. He understood the necessity of morality.

Kill the beast! Cut his throat! Spill his blood!