Madan (M R <[EMAIL PROTECTED]>) wrote: <Hope the new World Trade Center will be in 100 % SI. Currently I am vacationing in India.> It's interesting that you should mention SI in connection with the World Trade Center. The destroyed buildings *may* have been designed to metric specifications. During the first day's coverage, ABC News interviewed a structural engineer to find out why the towers collapsed. During the course of the engineer's explanation (the extremely hot jet fuel-fed fires weakened the steel walls, thus allowing the attached floors to break away and fall atop one another like dominoes), he mentioned that the external vertical beams were spaced 39 inches (1 meter?) apart, much closer than in other buildings. He said that this close spacing gave the towers plenty of redundant load paths to survive the airplane impacts, but that the softening of the steel from the heat did them in. Jason
