What the truth is about 9/11 and the demolition of the twin towers remains to be discovered. Certainly the official explanation does not hold water. You only have to read Richard Gage on the crush-down crush-up theory of Bazant to know what bunkum it is.“Evidently this crush down model and theory is complete nonsense, but it is the official explanation(s) of the WTC 1 destruction on 9/11! A small, fairly weak part C, 95% air, cannot possibly crush a big part A of similar structure only due to gravity and compress it into a 87.3 meters tall tower of rubble on the ground after 10 seconds! Anyone that has just dropped anything on something knows this. Try then to crush this something! You need a big force for that, which gravity alone cannot provide.”
Scaling the twin towers down and relying on layman’s terms the ‘big force’ needed would be something like the power-driving necessary to crush an aluminium beer-can. It would in fact need more since structural steel is stronger than aluminium. But because Newton applied his third law – for every action there is an equal and opposite reaction – across the range of materials, beer-cans make for a reasonable analogy. They are not perfectly analogous, for example, in a beer-can there is no inner core, there are no floors, doors or windows, but we can learn something from this very simple experiment.
To model the twin towers using beer-cans it is necessary to know the thickness of the aluminium. As I cut up beer-cans to make packing shim for my centre lathe I can tell you the thickness is 0.1mm (0.004″). The following are rough workings but good enough to demonstrate the scaling principle.
Circumference of beer-can = 8.15 inches = 0.68 ft
Perimeter of twin tower = 787.2 feet
Scaling is 1158 : 1
Thickness of beer can = 0.1mm = 4 thou.
Therefore for scaling up the beer-can walls to what they would measure at twin tower dimensions.
1158 x 0.004 = 4.632 inches
The thickness of the box columns in the twin towers were at their weakest 1/4 inch by 14 inch square. They also had spandrels welded across them of about 1/4 inch. These box pillars were spaced some 3 feet apart and welded together in strips of three across spandrels which I estimate themselves are five feet deep, ten feet wide and 1/4 inch thick. The inner core was even more rigid.
Scale models are used to test the viability of something being built. Engineers know that scaling up, and down works, as it should. That’s why they do it.
http://www.modelmakers-uk.co.uk/industrial-models
The structure of beer-cans is much less sturdy than the twin towers. When I did the above rough calculation to scale beer-cans to twin tower dimensions it surprised me to learn that it would take less than two and a half beer-cans to reach above twin towers proportions (about the same as you see in the photo). They look fatter but that is because they are cylindrical.
Anybody who still believes the nonsense that the top of the twin towers could cause a crush-down effect should stamp on a beer-can. Yes, it can be crushed down. But the amount of kinetic energy needed is huge. Also it does not always crush down evenly. It could not be done for example by dropping an empty, or even a full beer-can (believe me don’t waste the beer) so why anybody thinks it could happen to the twin towers is beyond me. Yet that is what those asking you to believe the crush down theory or the progressive collapse theory want you to believe.
Thankfully I never bought into that bunkum. But then I am a toolmaker. As Jonathan Cole quoting Feynman emphasised: “It doesn’t matter how beautiful your theory is, it does not matter how smart you are, if it does not agree with experiment, it’s wrong.”
All the Goss 
This article has three major problems.
First and most technically, there is the scaling problem. Scaled-down models do not behave the same as the full-size original that they represent. An obvious example is a pendulum. A 25 metre pendulum has a period of about 10 second. If we scale down by 100:1 we have a 0.25 metre pendulum, which obviously will swing faster. Should we expect the period to scale by 100:1 as well, to 0.1 second? In fact, a 0.25 metre pendulum has a period of about 1 second. Scaling is clearly more complex than it first looks, and anyone with a technical interest can explore just how complex it is here:
https://en.wikipedia.org/wiki/Scale_model
– “Similitude is the theory and art of predicting prototype (original object) performance from scale model observations”
https://en.wikipedia.org/wiki/Similitude_(model)
If we consider the beer can model of the Twin Towers proposed by John Goss at a scale of 1:1158, if they were to suddenly lose their solidity, the material at the highest point would fall to the bottom in 0.27 second. So the material would be acquiring energy from gravity for a much shorter time compared with the 415 metre Twin Towers; at a smaller scale, there is far less energy available for destruction of materials, because we can’t adjust Earth’s gravitational field. From a different but related field:
– ” Geotechnical engineers build scale models of dams, retaining walls, and structures all the time. But these models have one major shortcoming, and that’s the effect of gravity on fluid pressure. Because of their smaller surface area, scale models are subject to much smaller pressures than their full size counterparts. The pressure inside soil and structural members is extremely important to geotechnical engineers.
If you build a 1:100 scale model of a 100′ dam, you’ve really built only an actual-size model of the top 12 inches. The forces inside the model will not resemble the actual behavior of the dam. Engineers get around this by taking that scale model and putting it on a geotechnical centrifuge like the one in the link below. When you put that dam model under a static load of 100 times normal gravity, it will be subjected to the same forces and pressures as the real dam, and you can take useful measurements. “
http://www.nees.rpi.edu/
Incidentally, John’s 1:1158 model could not be tested in this centrifuge because the disparity of scale is far too great – the centrifuge cannot simulate anything near 1158 times Earth’s gravity.
The other problems with John’s article are that at 4.6 inch thickness, his scaled up beer cans are much stronger than the perimeters of the Twin Towers, even allowing for the additional strength of steel over aluminium – we may neglect the core structures because the video record shows that these still stood after the floor assemblies had been destroyed and the perimeters had fallen away outwards. Also, Bazant’s “crush down then crush up” is a highly specific model of progressive collapse, and not the collapse as recognised by most engineers -ie. it’s a straw man argument in the first place.
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What your Wikipedia link shows is what Feynman said: “It doesn’t matter how beautiful your theory is, it does not matter how smart you are, if it does not agree with experiment, it’s wrong.”
You are trying to discuss diversionary theories applied to fluid situations: ships, aircraft, submarines, earthquakes &C and it is only by testing that you can be sure the results are correct. I am sorry but too busy to discuss your other inaccuracies Clark. I should just mention that the inner core (remarkably) came down with the rest of the towers. Your comment makes out they were still standing.
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John, I of course agree with Feynman; “if it does not agree with experiment, it’s wrong”. But experiments with models are not the same as experiments at full size; that is simply a scientific fact – a fact which you seem to be denying. I am not being diversionary; those were the examples I could find, but the scaling problem of course applies just as much in structural engineering, and if you could ask Feynman, he would agree.
Likewise, I really don’t know how you can deny that the Twin Towers’ core structures (briefly) survived the major part of the collapses, since we have already discussed it:
https://www.craigmurray.org.uk/archives/2010/01/the_911_post/comment-page-101/#comment-641775
The following is the A&E911 video of former NIST employee Peter Ketcham; it has some of the best views of the core remnants that I have seen anywhere. They can be seen at 15:39 (vaguely), 17:38 (a high section which falls by 17:40, but it clearly stood after the perimeter and floor structures had already fallen), 21:06 and 21:13 (clearest shots of WTC2 core remnant after main collapse had completed), and 26:33 (close-up of earlier view):
Quite clearly, the interior floor structures and the outer perimeter structures had gone before the core structures finally followed them. This simple observation obviates any need for Bazant’s “crush down then crush up” theory. It disproves any theory involving Twin Towers being brought down from below by destruction of their cores, and it means that we can disregard the strength of the cores when considering the main collapses.
I’m sure Feynman would agree with this also: “If it contradicts observation, it’s wrong”.
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No he never said that. That appears to be Killickian metaphysics to me.
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Viewing 17:38 to 17:40 in the Ketcham video, the fact that we see the core remnant after the main collapse has passed disproves Bazant’s assertion that the “upper block” remained intact as it “crushed” the lower part of the building; it simply is not possible, because there’s what’s left of the core, sticking up clear as day after the top section of building has gone.
We can therefore ignore Bazant’s maths; it is simply irrelevant. “Crush down then crush up” is just as untenable as “cores destroyed by nukes”, because there is the core for all to see.
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