"the jet fuel was mostly spent on the initial impact. The fires were just smouldering away, no where near the 1500 deg C needed to melt the
steel."
Are you a fireman? Black smoke is not smoldering. It is full of volital gas's created from the building contents. Gas's which are created from the
heat of the fire.
The steel does not need to melt, just weaken and deform enough for the strength of the shape to change.
"The fact that the central pillars (40 or so?) filled with concrete and re-inforced steel that went from the top of the building to the bedrock
disintegrated, really makes you look harder at the whole thing. Sure if the floors pancaked the central pillars would still be there...."
The concrete has enormus compressive strength but low tinsil strength. It is used to encase the steel so the shape of say an I beam stays an I. Crack
and vibrate the concrete and the strength is less.
The central core supports only half of the load of the floor span. If the outside support fails the core could not hold up the rest of the
building.
This magazine which I subscribe to had several great articles on both the WTC and the Pentagon in regards to 9-11
www.bdcmag.com...
I believe the WTC was either a staged event, or the whitehouse knew it and let it happen to pave the way for the rest of their plan. I don't think
they expected the building to collaps.
I think the whitehouse restricting the air quality warnings is almost as bad as the attack.