This is an example of a partial core failure mechanism that pulls in the perimeter wall.
It shows that in general there are ways to create inward bowing along the perimeter of the building by partial core failure rather than with long truss sagging as the NIST claims.
A basic mechanism in which a partial core failure would pull in the perimeter is shown below.
DIfferent variations of pivots can lead to an inward bowing along the face of the perimeter of about 4 ft with only about 8 ft sagging of the 1000 row columns. That would be the maximum inward bowing seen on WTC1. WTC2 had much less inward bowing until the initiation sequence.
These geometrical possibilities were not considered within the NIST reports.
Created on 07/25/2011 12:08 AM by admin
Updated on 03/10/2013 10:02 PM by admin