Fold-in Nature of WTC7 Collapse
East wall folding over and onto building.
The event is recorded by femr in this video clip
GIF animation of the event here
More discussion here
The following photos are of the WTC7 rubble. There is very little damage to buildings located just across the street from WTC 7.
The exterior walls are folded inwards over the top of the rubble on all sides.
Interior columns fail slightly before the exterior
A close-up of the roofline descent shows the building interior fail slightly before the exterior walls.
In the quality video clip Close-up of Penthouse
One can notice, in order:
1) East Penthouse Collapses from left to right
2) Rest of penthouse collapses, all supporting columns seem to lose strength simultaneously.
3) The whole outside of the building follows closely behind. There is maybe a one second delay between the simultaneous failure of the penthouse columns and the equally simultaneous failure of the entire perimeter.
The whole penthouse fell slightly before exterior of the building because we can see a faster penthouse disappear within the building in the video.
This helps confirm the probable order of column failure. The interior columns failed just before the exterior frame, pulling the exterior inwards and over the interior.
The early fall of the penthouse allowed the building to fold inwards while falling.
Created on 10/01/2009 10:45 AM by admin
Updated on 02/15/2013 05:28 PM by admin