I am telling you that the *fact* that steel loses strength due to heat- in ordinary building fires, leading to structural failure - is known, and we are specifically taught how to design for that. Its a very small point. The building I posted a pic of was maybe 5 stories high, and you could see the sagging steel structure- it obviously at least partly melted. Put another hundred stories on that- I think it'd be flat, what do you think?
I agree that the incredibly uniform demolition of both towers strikes me as bizarre- but I have seen many bizarre things in the real world. In fact, a skyscraper is itself something of a defiance of the laws of physics, so maybe that holds in both erection and spontaneous demolition.
Here's a cool video of a 13 story steel building collapsing due to fire:
http://video.aol.com/video-detail/delft ... 3741771392
Another steel building destroyed by fire:
http://newsimg.bbc.co.uk/media/images/4 ... ire203.jpg
http://news.bbc.co.uk/2/hi/uk_news/engl ... 105942.stm
A spokesman for the fire service said the blaze had resulted in a black smoke cloud which could be seen for miles.
He added: "Intense heat buckled the steel girders holding the roof."
Here's a nice picture of a test subjecting a steel beam and a wooden glulam (timber) beam to 30 min of fire. Guess what? As you can see, wood (big, thick pieces) is more structurally sound for longer times in a fire than steel! (File under crazy but true...and things you learn in architecture school.)
http://farm4.static.flickr.com/3542/336 ... 0319_o.jpg
Theres unfortunately tons more examples- which is why they invented steel fireproofing. Its that stuff that looks like cottage cheese. Flocking, they call it. Theres also intumescent paint, which is basically paint which foams up in the presence of heat, turning into fire retardant insulation. Another technique used is to fill steel structural tubes with water.
Amazing how widespread this misconception is.
Why then heck cant I post pictures anymore? Is it the new forum?