It looks like you're using an Ad Blocker.
Please white-list or disable AboveTopSecret.com in your ad-blocking tool.
Thank you.
Some features of ATS will be disabled while you continue to use an ad-blocker.
To get this clear, the distinction you make between pancake collapse and crush down collapse is that in a pancake collapse the floor connections fail, and in a crush down collapse the support columns fail?
The details of the failure process after the decisive initial trigger that sets the upper part in motion are of course very complicated and their clarification would require large computer simulations. For example, the upper part of one tower is tilting as it begins to fall ~Appendix II!; the distribution of impact forces among the underlying columns of the framed tube and the core, and between the columns and the floor-supporting trusses, is highly nonuniform; etc. However, a computer is not necessary to conclude that the collapse of the majority of columns of one floor must have caused the whole tower to collapse. This may be demonstrated by the following elementary calculations, in which simplifying assumptions most optimistic in regard to survival are made.
For our purpose, we may assume that all the impact forces go into the columns and are distributed among them equally. Unlikely though such a distribution may be, it is nevertheless the most optimistic hypothesis to make because the resistance of the building to the impact is, for such a distribution, the highest.
Ok, forget the columns, forget the antenna, forget any mass but the 12 floors. Do you agree that when 12 floors fall on a single floor, the single floor inevitably fails? And once it has failed, 13 floors falls on the next floor, which also inevitably fails? And after that ones failed, 14 floors etc.. If you do agree to that, do you also agree that collapse was inevitable once it was initiated?
He says it himself. His "crush-down" model as you call is is "Unlikely". He assumes that all the impact force go into the support columns because it is in favor of arrest. That did not happen in reality. So crush-down as you define it did not happen. In the "official explanation" crush-down as you define it is called "unlikely". (if you count Bazants work as official explanation).
Originally posted by Darkwing01
No.
One floor impacts one floor.
....
So each time you have a collision the pancaking collisions become more and more like crush down collisions.
But this isn't Bazant's crush down, it is not an indestructible element impacting a frangible lower body in a one-dimension. This is uncompacted rubble we are talking about, the coefficient of restitution has now grown to enormous proportions.
So at this point it is no longer possible to speak in any meaningful sense of however many floor impacting however many floors.
Go back to the rice falling on the scale: Take that same pile of rice out of the packet and drop in onto the scale, see the difference?
Which makes it all the more telling that they decided to go with this over pancaking.
Pancaking doesn't work because you can't fudge the numbers as easily and the projected collapse time even without losses just doesn't add up.
So your conclusion is that once the collapse is initiated, complete collapse in inevitable?
You have already given 2 different definitions of "crush-down", and I haven't even given my own definition yet. This is why these terms only confuse discussion.
It only causes confusion, this reaction being proof of that.
.
Pancaking as a model doesn't work? Pancaking as a hypothesis doesn't work? Pancaking as an explanation does not work? Describe what it exactly is that does not work without using the term pancake
Originally posted by Darkwing01
No, the only thing that is inevitable is that collapse would eventually be arrested.
You description of the collapse does not work as a model because has no connection to what can readily be observed in the collapse footage, in fact it directly contradicts it. It also doesn't work as a model because it only addresses the first in a putative series of iterations and fails to account for the rubble which formed during the collapse.
Your description of the failure of the floor assemblies does not work as an hypothesis because it is falsified by the rubble pile and computed collapse time.
It does not work as an explanation because it doesn't explain what is to be explained: How the collapse happened so fast, so completely and so symmetrically.
Your theory basically amounts to this:
-Something heavy fell on something else, breaking it.
-[Insert Miracle here]
-The government would never do such a thing.
-Therefore gravity alone was responsible.
You nailed it. Therefore this must be the truth after all
Then explain which floor would eventually arrest the collapse. How is this possible when there is the mass of at least 12 unsupported floors above it? How can a single floor support the mass of 12 floors?
Originally posted by Darkwing01
PLB!!!!
It is one thing to quote out of context, but it is quite another when you start criticizing the preamble or conclusion for not being the main body. Just two posts above I gave you a detailed outline and you have given NO indication that you understand it.
Until you can demonstrate that you have some grasp of what I am talking about it isn't really worth discussing.
It is a tough question for you to answer, I understand why you are avoiding it. Still, too bad you choose to chicken out.
But after this the floor is wrecked, it is not a connected assembly anymore, by the time all 12 floors have been destroyed like this you no longer have floors, you have an uncompressed heap of rubble. So each time you have a collision the pancaking collisions become more and more like crush down collisions.
Which floor is going to arrest this mass? How come this floor is capable of holding this mass? Explain this.
Originally posted by -PLB-
reply to post by Darkwing01
You think the majority of mass falling not down (the direction gravity is pulling it), but falling to the side? What force is causing this to happen? How is this a reasonable assumption to make?