Posted: Dec 04, 2010 12:38 pm
It's complicated enough that it took thousands of years of architecture to figure out how to keep a building taller than a hundred feet or so from falling over.
A common vein throughout claims that the towers could not have fallen due to airplane impact & fire is the assumption that the building is strong. All skyscrapers are relatively weak. The only reason they stand is because of careful and precise designs which distribute the weight ever so carefully. Like a bridge, if you remove or sufficiently weaken just a few pieces the entire structure will fail, since each piece is dependent on the other pieces for its strength.