Originally Posted by wombat2u2004
According to my brother in law who is a New York based Engineer, he explained to me in 1980 on a visit we both had to the WTC, that those two buildings were very heavily designed to take sideward movement.....it's because of very high winds at that height. They even had a sway factor engineered into their construction to compensate for those heavy winds.
A five metre sway factor, that if exceeded, would enable lifts etc etc to actually shut down.
The impact of those aircraft into those buildings may well have caused that sway factor to be exceeded, thus stopping the lifts from working.....but certainly not enough to move those building at the angle required to intiate a toppling momentum.
The heat generated by exploding fuel would have almost melted the structural components required to support the loads placed upon them from above....therefore, upper floors falling on lower ones (which were not designed to take a FALLING weight, but only dead and live loads), impacted to such a degree on those lower floors as to create a crushing action.....the rest is history.
Wombat