• Journal of Engineering Mechanics: Discussion of "Progressive Collapse of the World Trade Center: A Simple Analysis" by K.A. Seffen
Dr. Crockett Grabbe
WTC Building #7, a 47-story high-rise not
hit by an airplane, exhibits all the characteristics of
classic controlled demolition with explosives:
(and some non-standard characteristics)
And exhibited none of the characteristics of destruction by fire, i.e.
1.
Slow onset with large visible deformations
2.
Asymmetrical collapse which follows the path of least resistance
(laws of conservation of momentum would cause a falling,
to the side most damaged by the fires)
3.
Evidence of fire temperatures capable of softening steel
4.
High-rise buildings
with much larger, hotter, and longer lasting fires have never “collapsed”.
As seen in this revealing photo, the
Twin Towers' destruction
exhibited all of the characteristics of destruction by explosives:
(and some non-standard characteristics)
No precedent for steel-framed high-rise collapse due to fire
And exhibited none of the characteristics of destruction by fire, i.e.
1.
Slow onset with large visible deformations
2.
Asymmetrical collapse which follows the path of least resistance
(laws of conservation of momentum would cause a falling, intact, from
the point of plane impact, to the side most damaged by the fires)