Quote (Santara @ Sep 11 2012 01:36pm)
I thought that was pretty straightforward. Plane impacts building, with inertia vastly greater than that planned by the design, breaks portions of the flame retardant from the I beams, and a combination of uneven expansion/contraction coupled with steel being weakened to roughly 50% of its load capacity, then collapse.
before u conclude how much the steal weakened u have to know how much heat it absorbed right?
and its not straightforward there is a huge section in the nist report ont his topic and in fact a sophisticated software had to be build to simulate it