If you don't know this one yet, watch it now: video.google.com... – Building the World Trade
Peace be with you!
I strongly believe that even had the fires weakened the steel, the steel (only in the hot floors of course!) would merely have bent slowly, maybe
tipping the top of the towers a bit, if things went really wrong let it slide down, but NEVER crashing down on the base, with only this impulse,
making it look like somebody from beneath the earth was pulling the rooftop through hundreds of meters of steel on a long string. It's just a feeling
that the structure was not that feeble.
We would only have to build something with a similar structure, that's also weaker and that would be more prone to what we were told collapsed the
real WTC Towers.
You are very right. Okay, let's be very generous then. What we need then is a roughly cylindrical object, and it has to be weaker than the original.
Good! The original towers crumbled, so our object will have to fail too! Still, it must be strong enough to withstand minor impulses: wind, maybe even
a small „earthquake“. Let's say it shouldn't fall to pieces by merely staring at it menacingly.
In short, we will have to find some material and a very basic way of copying that architecture: a core, and a perimeter wall. These were allegedly
responsible for sensible stability of the towers. Fine.
It must be possible to lift the top ¼ of the object up. When we let it drop from a certain height (let us find a very generous way to simulate the
impulse ( = mass * velocity; verlocity can be derived from earth g = 9,81 m / s² [generous because it assumes the columns have „disappeared“
instead of bent])), it must smash the whole model beneath it.
Logically, it now depends on only a few parameters wether it succeeds or not: is the top heavy enough? Is the structure strong enough? Does it fall
fast enough (dependent on height only, not weight)?
I must admit ignorance on some of these subjects. For example: How do we measure stability in physics? I know there are a few engineers here who could
help us out on this. It is totally okay if we have to make some very generous estimations here. We wanted to be generous.
What else is important? The density, i.e. the ratio of weight to volume? It may be useful. Do we have to make estimates on the weight of the towers?
The volume should be easy, I bet I'd find the height and length of them if I weren't too tired to google already – 'll do tomorrow).
In the meantime, try to build that model in your head. Visualize it. If you play guitar with steel strings, take a piece of string and try to bend it.
It's easy, right? Cut it in half and notice it getting harder to bend the shorter it gets. We're not surprised. Try to imagine it being so short
that it fits the original weight
/height/width ratio of the perimeter wall segments. Watch the video again for reference, and take into
consideration that the original segments were hollow. Now try to imagine our model being made of such „guitar string segments“ (that'd be a lot
of glueing). Reduce it to 20 or so floors, a small segment. For the core columns, let's generously assume the thickness of small paperclips or a
needle. And for the trusses, let us do a lot of weaving – with a thin string of silk. I hope that's generous enough.
How large would the segment be now? As big as your room? Hardly. Your table? Maybe.
Now ask yourself: how heavy would any object have to be that we let drop on top of our beautiful model segment to flatten it totally?
Very heavy? Try a few things in your mind – a book, a loudspeaker... does it work? Or does it just deform here and there, bend maybe? Try something
heavier, your PC, for example. Be generous.
I really wonder if it's just me or if I'm making wrong assumptions.
[edit on 13-9-2006 by Akareyon]