posted on Dec, 6 2007 @ 08:52 PM
Les Robertson's group was only one of the engineering groups on the WTC project, and his wasn't
the group that did the plane impact
calculations and published them.
The firm that published information on the designs' capacity for plane impacts was Worthington, Skilling, Helle & Jackson.
This particular item of information was the 3rd point on an eleven-point white paper that firm released while the towers were being designed:
3. The buildings have been investigated and found to be safe in an assumed collision with a large jet airliner (Boeing 707-DC 8) traveling at 600
miles per hour. Analysis indicates that such collision would result in only local damage which could not cause collapse or substantial damage to the
building and would not endanger the lives and safety of occupants not in the immediate area of impact.
--City in the Sky, p 131
Note that what the above quote says must have been true because it was proven with a heavier plane (767) on 9/11. The plane impacts severed less than
15% of the columns on the impacted floors in either building. If you think that's a lot, then look up the concept of a "safety factor" in
structural engineering. The fires would have had to have done at least 4x the damage of the impacts to bring the structures to the brink of collapse
with a generalized safety factor of only 2 for the impacted floors.
[edit on 6-12-2007 by bsbray11]