This is an open challenge, open to anyone who believes the WTC Towers collapsed under their own weight after only fire and impact damages. It has
been around for at least 4 years to my knowledge but I have yet to see a single model of the collapses that satisfies it. It is based on plainly
The challenge is in 5 parts, from the easiest to the most difficult.
All five require building a structure that will undergo top-down progressive total collapse -- i.e.: when disturbed near the top, it will collapse
from the top down to the bottom, leaving no part standing. The disturbance can include mechanical force, such as projectile impacts, and fires,
augmented with hydrocarbon fuels. Explosives and electromagnetic energy beams are not permitted.
Your structure can be made out of anything: straws, toothpicks, cards, dominoes, mud, vegetables, pancakes, etc.
The designers of the Twin Towers were able to meet all 5 challenges using steel and concrete.
Build an upright structure that will undergo progressive collapse.
Build an upright structure with a square footprint and an aspect ratio of at least 6.5 (6.5 times as high as it is wide) that will undergo progressive
Build a structure as required by CHALLENGE #2 which, in the collapse process, will throw pieces outward in all directions such that at least 80% of
the weight of the materials ends up lying outside of the footprint, but their center of mass lies inside the footprint.
Build a structure as required by CHALLENGE #2 which is also capable of withstanding a 100 MPH wind without collapsing. The structure has to be closed
in the sense that it cannot allow air to pass through it.
Build a structure that meets the requirements of both CHALLENGES #3 and #4.
Challenge #5 can be completely ignored until someone gets that far, as far as I am concerned.
The challenge is simply to build a model structure, any model
, that can
a) undergo a progressive collapse,
b) is at least 6.5 times as tall as it is wide,
c) 80% of the debris has to land outside of the footprint (which is square).
The requirement, that the model be able to withstand 100 mph winds, something about that does not sound right to me. I agree it's important to
remember that the WTC buildings themselves could support significant lateral loading, hurricane-force winds even, so that they were NOT just a literal
house of cards, but I'm not as certain that the force would scale to the building materials effectively. Like I said, I doubt anyone will even
manage to get to part 5.
People always say the reason NIST never modeled the global collapses, or attempted to analyze them in any way whatsoever, was because the collapses
were much too complex to analyze.
Well here is a way to reproduce things that both WTC Tower collapses accomplished, in a simple way yet in a
way that simultaneously proves that all of these features are indeed possible!
And also to reiterate, it still has yet to be accomplished. I think, because it is impossible, because there was more to the collapses than just
fire and plane impacts. But I would love to be shown any model that accomplishes these things.
So can anyone come up with any sort of model at all, that undergoes progressive collapse while shedding at least 80% of its mass to outside of its
footprint? It's been some number of years and the answer appears to be NO
No evidence that a building can withstand a progressive or 'pancake' collapse while still meeting this condition, because the theory and the facts
contradict each other. This theory says most of the PE/KE (mass) went to crushing the building below, while facts tell us that the clear majority of
the mass was being ejected outwards. And apparently no one can demonstrate that both are possible simultaneously. This is not surprising to me, like
many other people, because the theory was counter-intuitive in light of this information in the first place.
Edit to add, Bhazant, Greening and others did an energy calculation that assumed so much mass was lost over the sides of the buildings as they
collapsed. They were not able to allow the ~80-90% mass ejection indicated by photographs of Ground Zero without throwing their calculations off and
giving collapse times longer than reality. So they assumed a much smaller amount of mass was ejected, suggesting that 50% or more of the total mass
of either tower was STILL in its footprint when it was done collapsing. So here we even have theoretical/mathematical evidence to support the idea
that ejecting so much mass and still maintaining a "progressive collapse" is impossible, aside from the fact that no one has been able to physically
demonstrate it in the simple terms provided on this thread. Bhazant, Greening, etc. had to assume half of each building was still within its
footprint, among a lot of other hairy assumptions, just to get a theory to work out on paper. Red flags should be going up for anyone who likes
theories to fit with the actual data...
[edit on 12-8-2009 by bsbray11]