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Rath said:
sethnintendo said:


Okay say the jet fuel did weaken the steel enough.   Do you really think that the steel would be weaken on all sides of the building evenly to have the buildings collapse onto themselves perfectly.  To me it would seem that the side that got hit would make the building topple over from that side.  However, according to you and the official explanation all the sides must have burnt and weakened the steel evenly.


The steel weakens the most where the fire is strongest, these beams can no longer bear load. Extra load is therefore put on surrounding load bearing beams. This eventually causes mass collapse in the direction of the force acting upon it - gravity acts downwards not sideways.

The actual physics behind the collapse are well explained

http://www.civil.northwestern.edu/people/bazant/PDFs/Papers/466.pdf

You clearly have misunderstandings of 'the official explanation' and the physics involved if you think that for a building to collapse upon itself all sides must have been equally weakened.

Okay well what I pulled from the Northwestern document why it didn't topple over was because

"Before disappearing from view, the upper part of the South
tower was seen to tilt significantly and of the North tower
mildly. Some wondered why the tilting did not continue,
so that the upper part would pivot about its base like a
falling tree of (Bažant and Zhou 2002b). However,
such toppling to the side was impossible because the horizontal
reaction to the rate of angular momentum of the upper part would
have exceeded the elastoplastic shear resistance of the story at
least 10.3x( Bažant and Zhou 2002b)."

just trying to think about in layman's term and can't really understand it because I don't know what elastoplastic shear resistance is or how they would even calculate that.

Now check it out on video at 20 secs in:

http://www.youtube.com/watch?v=iwN-koZt1Ig&feature=autoplay&list=PL621A4B03C1169C78&index=10&playnext=10