I think that some folks are asking questions which are answered on NIST’s website:
Particularly questions about how fast the building came down (compared to free fall) and why it appeared to come down symmetrically. Please take a gander and see if that helps.
In previous WTC threads I’ve offered my opinions on certain technical issues and those are based on my education - I have a BS and MS in structural engineering from UIUC (one of the top CE schools in the country). For folks who are making statements about what is and is not possible on technical issues may I ask what your education or work background is in the related fields?
Carson, for example, you mentioned you’ve done steel fabrication work. Alex, how about you?
Carson, as far as heating steel goes: Structural steel loses about 50% yield strength at 600C (about 1100F). It’s metal and will heat up very quickly. At lower temps the loss of strength isn’t so catastrophic but thermal expansion can result in major stress as the structures geometry changes - joints could break, beams and columns can buckle.