Hey Sean,

Yep, that was my issue too.  In fact, the main critique of the NIST report is that it deals only with the failure and collapse of the top portion, suggesting as a given that that was enough to make the rest of the undamaged tower not just buckle but also break into small pieces.  Another point of criticism is that the NIST report does not factor in the dissipation of heat through the steel which means the heat would not have accumulated just in the damaged section.  This is also suggested by photos of people (i'll link to them when i find them again) poking their heads out of the damaged sections.  If there was such a blazing and hot inferno localized in those sections/floors, how could anyone have done that?  Also there is audio evidence that firefighters had reached some of those sections and reported the fires under control.  Also at issue is the testimony of William Rodriguez and others who were in the basement and heard an explosion beneath them...

gretavo

Sean Ingham wrote:

I apologize if this question has been answered already or is naive and too
speculative: Is the official theory that the heat weakened the steel supports
for the floor or a set of floors near the plane impact so that these could
collapse, and then the force generated by the initial collapse of these floors
was great enough to cause the collapse of the floor immediately beneath them,
and, a fortiori, the floor beneath that one and so forth?  If causing the
collapse of floors at the top generates so much force that their collapse
induces the collapse of floors beneath them, why do demolition crews bother to
rig explosives to every floor?  That is, why not rig explosives to the top
floors and then let their collapse trigger the collapse of the floors beneath? Is it just overkill?  Best, Sean