re: #366 BigPapa

Add to that, that steel’s strength is reduced by more than 50% when heated to the temperature of burning jet fuel. Therefore, steel does not need to melt to weaken and fail.

I’m shocked that the buildings held on for as long as they did.

I thought at the time that it was a tribute to I.M. Pei, the architect, and the team under him who designed and built them. According to a book I have on the WTC (one I’ve had for years before 9/11/2001), the towers were designed to survive the impact of the largest airliner around when they were put up- the Boeing 707, which was a lot smaller and less massive than the ones that hit them. Pei was worried about a repeat of the July 28, 1945 crash of a USAAF B-25 Mitchell medium bomber into the Empire State Building, and he knew that a steel-skeleton, glass-box high rise just can’t be built as strongly as one whose steel skeleton is covered mostly by granite, like the ESB. He built the Twin Towers strong enough so that if a four-engine jetliner (about half the size of a 757) hit one, it would stand up long enough to be evacuated.

It’s a measure of his true genius as an architect and engineer that it worked better than it had any right to, considering what actually happened.

cheers

eon