posted on Feb, 2 2005 @ 04:31 PM
Originally posted by General Zapata
Originally posted by HowardRoark
The initial impact caused severe damage to a large percentage of the structural steel framing. It is entirely possible that even without the
subsequent fires, that damage would have been enough to cause the collapses.
If this is true, then the WTC would have to be the single worst failure of structural engineering ever. It would take very, very dodgy engineering for
this to happen. Very unlikely.
Actually, that could have been the very case. Although the Designers supposedly designed the building to withstand the impact from an airliner, you
have to wonder what sort of assumptions they made regarding that impact. In any case, the damage wrought by the impacts was extensive. And was
certainly not something that could have been reasonably foreseen. Hindsight is always 20/20.
both of the impacts breached and damaged the core areas. This allowed the fire to travel rapidly up the building. This is clearly
evident in the videos of the moments before the collapse.
listen to the mp3 recording of the firefighters. They say that the fire is localized to 2 or 3 floors ONLY, and that they could control it. This was
just before the building gave way.
No, they had just reached the bottom
of the fire floors. It looked controllable, because the fire front had moved on. Look at the videos just
before the collapse. There were fires burning on floors well
above the impact points.
The floor slabs in the area of the impact were ripped away. These slabs also contributed to the structural strength.
incorrect. As a student of engineering, I was taught in first year structural that floor slabs in a building are classified as extra-structural
fixtures. They should have no bearing, in a well designed building, on the building's overall structural integrity.
If the building was a standard beam and column construction with either diagonal wind bracing or a masonry core, that would have been the case. The
WTC towers were not typical buildings. The floor slabs played an integral part in stiffening the structure. Google it if you don’t believe me.
As different parts of the building heated up due to fire and others cooled, the affected parts of the structure expanded or
This is really grasping at straws. The coefficient of expansion of steel is indeed relatively high compared to other materials, but no where near
enough to cause such drastic changes at so low a temperature. The steel would have melted LONG before it warped enough to sufficiently damage the
structural integrity of the building. Railway tracks are spaced at a few centimeters apart for every mile or so of track. This shows you how little
steel will expand in this case.
Expansion of steel framed structures under fire conditions have been extensively studied.
Also, there is a difference between a steel column heated by a fire and a rail track in the sun.
There is a difference between unrestrained expansion of steel and restrained expansion.
Expansion is not an exponential function. It is in fact somewhat logarithmic. If the heat doubles, the expansion will not double.
That makes no sense.
[edit on 2-2-2005 by HowardRoark]