In view of the
description of how the "designed to withstand the impact of an airplane" myth saw the light posted recently by Oystein in another thread (thanks, Oystein), I take back my taking back.
The towers were not
designed to withstand the impact of an airplane. They were designed to withstand a hurricane of a certain magnitude, and as a result of that resistance, it was found that the force exerted by a plane at 600 mph would not be enough to tip it over.
Robertson even contradicts himself in the
NAE article:
The two towers were the first structures outside of the military and nuclear industries designed to resist the impact of a jet airliner, the Boeing 707.
(p.7)
These charts demonstrate conclusively that we should not and cannot design buildings and structures to resist the impact of these aircraft.
(p.8)
After reading the cited post by tfk, I'll go with the second quote.
Robertson does not contradict himself, he says he considered a 707 in the design, at 180 mph, in the Charts.
Robertson is saying he designed for an impact of an aircraft accident, the mostly like would be lost in the fog slow speed.
Robertson says we can not design for Terrorists flying planes at high speed. That is not contradiction, it is a different point.
Robertson never said 600 mph, at best that is what you said; some Port Authority engineers took the lateral numbers and ran the energy/momentum of a 600 mph 707 and found the towers would not topple, not a good analogy and there is no one to confirm the 600 mph design point. It could be worse, the Port Authority found out Robertson designed for a 707 impact, and they looked up the speed of a 707, found 600 mph in the Boeing 707 data sheet, and published it. Blind BS, or was some physics involved. The White Paper with 600 mph 707 was a bragging marketing tool, not science, more like propaganda, how much was right?
The building can resist low speed impacts, it can't resist high speed impacts; not contradiction, but more like What Is.
It is both
http://www.nae.edu/File.aspx?id=7345 .
"We should not and can not design buildings and structures to resist the impact of these aircraft."
Robertson is talking about the terrorists attacks, not a 707 lost in the fog, but an attack by terrorists planes.
The towers were designed to resist an impact from an airliner, Robertson clearly states it, and presents his chart above for the energy involved.
The two towers were the first structures outside of the military and nuclear industries designed to resist the impact of a jet airliner, the Boeing 707.
Not a contradiction. Robertson says the towers resist impacts from low speed aircraft, and not high speed aircraft. Like your car, can resists an impact at 5 mph into a wall, but not 50 mph. Simple physics. You don't need computers to do the calculations, in fact computers don't do calculations, people do. To say Robertson could not do a calculation of aircraft impacts is BS.
Anyone who says the WTC were designed to resist an aircraft impact, they were right, a low speed aircraft impact, as Robertson did, and explains.
