(bolding mine)
This is at least interesting because it might explain, with Heiwa's supposed background, why he's failing to grasp the realities of the WTC collapses.
WTC collapses - Layman's terms again
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This is at least interesting because it might explain, with Heiwa's supposed background, why he's failing to grasp the realities of the WTC collapses.
DC
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DC
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Pomeroo
instead of flaming others, you should take care that Marks tells NIST where they can find the once molten "aluminium" that came out of the tower, so they can test it, and dont have to speculate.
i find it pretty unfair that NIST and the rest are left with guessing while Mark had it in his hands and knows what it was.
Zorglub
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Sure, start by retract your claim that the people who jumped from the towers did so because they we´re intimitaded by the news they saw on TV. You have claimed this was the reason, not the raging fires leaving the victims with little choice but being burned alive or jump to a certain death.
funk de fino
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i am sorry in case you did read it by now
I read it before, so that is not an apology. Always the dishonest child aren't you?
DC
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i ask my self, how honest are you?
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Hm - a 33 000 tons ship at 5 m/s (10 knots) horzontal speed at collision has evidently more (2.78 times!) KE than an upper block of WTC 1 (also 33 000 tons) but only contacting vertcally the lower structure at 3 m/s.
The contact area is also very different. The ship's bow is pointed, the upper block is a 4000 m² floor flat. Assuming uniform density of the upper block and uniform impact over 4000m² the impact pressure is pretty low. The peak pressure is time dependent but remember - the columns only occupy 0.13% of the floor area. The rest is the upper floor of the lower structure that is subject to the pressure. Actually the same pressure is applied to the lowest floor of the upper block.
The ship collision may stop after a penetration of 5-10 meters into the other ship (of same size). The pointed bow of the striking ship really breaks the side of the stricken ship but after a while (even if the driving force of the striking ship is still on) the destruction is arrested.
Why the upper block of WTC 1 would cause the lower structure to collapse is beyond me. See http://heiwaco.tripod.com/WTC1slicea.GIF .
I would expect that only the columns of the upper block and the lower structure would slice the floors apart of respective parts and that the floors would get entangled as seen in the right figure of the link above. Two walls of the upper block may then have sheared off and fallen to the ground. The rest of the upper block remains in the top of the lower structure. The lower structure would still stand. Quite basic actually.
So pls re-do your energy calculations using my observations.
Kind regards
Heiwa
Bazant and Greening just did it!
http://www.civil.northwestern.edu/p... Did & Did Not Cause It - Revised 3-31-08.pdf
They start off with Abstract: Previous analysis of progressive collapse showed that gravity alone suffices to explain the overall collapse of the World Trade Center towers.
Gravity alone? Sorry, only by using very false assumptions that idea can be shown to be valid using some math of dubious standards. Correcting the math will invalidate the hypothesis. And an intact upper block during the whole push-down of the lower structure is one basic assumption. Pure madness of course. And then that the upper block is destoryed by a push-up on top of some rubble. My children (test) audience was screaming with laughter when I explained how stupid that was.
In my view Bazant and Greening have a hidden agenda!
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Newtons Bit
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What a brilliant display of truther density. You still haven't understood the difference between actually believing something and making an assumption to make math easier. Or perhaps you intentionally refuse to understand the difference.
Here's the list of Dr. Bazant's publications: http://www.civil.northwestern.edu/docs/Bazant/publicat.pdf
That's over 480 publications. This man is a leading expert in engineering. And he has been so for almost 3 decades. Are you seriously trying to suggest that he "doesn't know anything about how steel structures behave after local failures and only subject to gravity force"? And where's your list of publications again?
Heiwa:
I can assure you I do not have a hidden agenda, but if you believe I do, could you tell me what you think it might be....
All the collapse calculations I have seen, (or carried out myself!), involve approximations and assumptions. Either you do complex FE modeling or you HAVE TO simplify the problem and focus on the basic physics of the collapse. In my earliest calculations I ignored the possibility of simultaneous crush-up and crush-down, just to simplify the math. Later on I HAVE attempted to include initial crush-up but I believe it does not make much difference to the calculated collapse times. If you consider that the energy to collapse one floor, a quantity I call E1, is expended over 3.7 meters, you will have an energy of 2E1 expended over 7.4 meters in a simultaneous crush-up crush-down situation; it follows that the RATE of energy consumption with drop height remains essentially the same as in the pure crush-down case.
In the end we are looking at the rate of momentum buildup, which mostly depends on the velocity of descent of the upper mass, (the change of mass is secondary). As long as the collapse "power" exceeds the rate of work needed to overcome the resistive force offered by the lower section of the building we have a self-propagating collapse.
I can assure you I do not have a hidden agenda, but if you believe I do, could you tell me what you think it might be....
All the collapse calculations I have seen, (or carried out myself!), involve approximations and assumptions. Either you do complex FE modeling or you HAVE TO simplify the problem and focus on the basic physics of the collapse. In my earliest calculations I ignored the possibility of simultaneous crush-up and crush-down, just to simplify the math. Later on I HAVE attempted to include initial crush-up but I believe it does not make much difference to the calculated collapse times. If you consider that the energy to collapse one floor, a quantity I call E1, is expended over 3.7 meters, you will have an energy of 2E1 expended over 7.4 meters in a simultaneous crush-up crush-down situation; it follows that the RATE of energy consumption with drop height remains essentially the same as in the pure crush-down case.
In the end we are looking at the rate of momentum buildup, which mostly depends on the velocity of descent of the upper mass, (the change of mass is secondary). As long as the collapse "power" exceeds the rate of work needed to overcome the resistive force offered by the lower section of the building we have a self-propagating collapse.
DGM
Skeptic not Atheist
But to accept this Heiwa would have to take gravity into consideration. Why do that if "gut feelings" are all you need?
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You referred to scale model tests and computer simulations that show limited penetration and damage from colliding ships. I looked and found that those tests involved 1,000 ton ships, unless there were other tests I'm not aware of. Please show the evidence that colliding 33,000 ton ships would behave the same way. I'll assume that they would, for the purpose of argument below, but I'd like to see the evidence. (Pointing to an authoritative text stating something like "all nautical collisions between ships of equal size behave the same regardless of scale" would be sufficient, but I doubt you'll find such a claim.)
Okay, but the upper block accelerating at 0.5g (due to the residual resistance) for 3 meters develops a velocity above 5 m/sec, so let's say it's the same velocity (and thus the same kinetic energy) as the 33,000 ton ship.
The colliding ship stops because the kinetic energy is limited. I accounted for the additional engine thrust; it's significant (at least, if you assume as I did, somewhat unrealistically, that all of the engine horsepower is converted into thrust with 100% efficiency) but not a large contribution compared to the initial kinetic energy.
The ship has a pointed bow that concentrates force, but it's penetrating steel plate that's designed to resist the force of ocean storm waves. The falling tower block has steel columns that also concentrate force, but they're penetrating concrete floors designed to resist the force of desks, chairs, filing cabinets, and people walking on them. (Surely, you're aware that a ship with a hull made of a few inches of concrete layered onto 22 gauge steel would crumble as soon as it was launched.) So I'm not giving the colliding ship any penetrating advantage over the colliding upper block. For the sake of argument I'll say it's the same -- that the kinetic energy of the upper block at 5 m/sec can cause it to penetrate the same "5 to 10" meters into the lower block as the colliding ship penetrates into the target ship's hull.
But wait -- by the time it's penetrated 5 meters of the structure below, the 33,000 ton upper block has gained another 1.6 billion Joules from the conversion of gravitational potential energy. This is far more than the about 400 million joules of kinetic energy it had when it was going 5 m/sec. Remember that the 400 megajoules of kinetic energy at 5 m/sec is more than enough to penetrate the 5 meters; the colliding ships prove that. So all that additional potential energy gained from graviational force acting on the upper block is free to become kinetic energy. So the upper block has not stopped, it has not slowed down, it has in fact sped up; the 33,000 tons are now moving at almost 10 meters per second.
If the kinetic energy of the upper block moving (let's use your smaller figure now) at 3 m/sec (150 megajoules) is sufficient to penetrate even half a meter of the structure below, then by falling that half a meter the upper block has gained back those same 150 megajoules from gravitational potential energy, and the collapse will continue.
That's what Apollo20 means when he says "gravity overwhelms everything."
I'm aware of that. But I'm doing my best to help.
What you've failed to take into account is that in each of your successive figures, the upper block has gained more energy than it lost from resistance.
Also, your figures suggesting that the resistance increases enough to arrest collapse because the upper and lower structures get increasingly entangled in one another do not depict a possible scenario. The lateral forces on the column ends (your black lines) in the fourth drawing are too large for them to stay connected. They break apart at their welds. And the floors cannot fall past each other as you've depicted in the 5th frame and cannot support the weight of multiple other floors stacked up on them as you've depicted in the 4th frame. So, the situation in your fifth drawing cannot develop.
If you're ever at a construction site, and the top couple of floors of framework start falling, do not think, "it's okay, they'll get tangled in the lower framework and won't fall all the way to the ground. I have nothing to worry about." Instead, run.
Done.
Respectfully,
Myriad
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Yes, but topic is his latest article, ref [2] in my article, where Bazant/Greening et al suggest that the WTC 1 upper block remains intact during push down and is destroyed afterward by a push up on top of some rubble. It seems Bazant has no idea about collapse arrest of locally failed steel structures. Nobody is perfect!
Here is my post from April 16. You ignored it completely. None of the fantasists posting in this thread have responded to my question, Does the misalignment reduce the momentum of the falling mass? Here is another opportunity to provide a yes-or-no answer.
Heiwa has demonstrated that he is an incompetent.
Mark, who you described as "questionable," seems to have covered the matter of the aluminum pretty thoroughly. If you had read what he wrote, you'd know how to find the sample he held.
My post from April 16:
Can we assume that you won't be attempting to answer my question, either?
Here's a sunburst: I cannot possibly remember everything that is said on the shows I host.
Here is what Mark wrote:
"One of the benefits of my work is that I sometimes get tours behind the scenes in a wide range places: theaters, TV studios, skyscraper mechanical systems, power plants, laboratories, museums, and exhibits.
The pieces of WTC aluminum I handled had characteristics of having cooled while falling in the air (I suppose falling through water is also a possibility). The curator said to me "I bet you can't guess what this is," but I guessed right away. This was before I knew of the conspiracy nonsense or the video of molten material coming from the south tower.
There is a place where the public can handle small debris from Ground Zero: steel, glass, and rubble (which has been cleared for this purpose by investigators and by families). I'm not going to advertise it here because I'm certain that 9/11 deniers would steal these things. People can PM me if they want to visit that place.
At Ground Zero, on Liberty Street next to FDNY 10 House there is a small exhibit that includes large pieces of structural steel, the battered uniform of a fallen firefighter, part of an aircraft fuselage, metal that has melted and cooled (appears to be mostly aluminum), and other artifacts from the towers. Tribute 9/11 WTC Visitor Center (http://www.tributewtc.org/)"
We conclude, then, that Mark told the truth, and--surprise!--the liars were attempting to twist his words. As usual, I am left wondering why you, a fantasist, would call attention to a statement that lends no support whatever to the false claims of your evil movement.
Very good - you redid the energy calculations. If your read my home page you find that once we investigated 200+ collisions where oil tankers were stricken by other ships and what happened then. Apart from oil spills in a minority of the collisions (most damage is just above waterline) all collisions were arrested sooner or later. Similar statistics are available for other type of collisions, incl. 33 000 tons ships hitting other ships.
Re WTC 1 the collision energy involved is very small and as soon as it is applied to both parts, it starts to destroy the parts. Both parts. As outlined in my article at http://heiwaco.tripod.com/nist3.htm .
This means, among many things, that energy is consumed and should result in a deceleration, and that parts may shear off and drop down. The energy of those latter parts do not then contribute to anything (than hitting bystanders in the way).
The conclusion of my article is that the WTC 1 upper block (mostly air inside the very solid columns and the thin floors) would have been destroyed after falling on the lower structure due many local failures (floors being sliced by columns) and that two of the upper block walls may shear off and drop down while all the floors remain entangled into one another. This is a typical collapse arrest of a steel structure.
The energies involved are consumed in this mess. Quite easy to calculate actually, if you do the effort. Anybody suggesting that the upper block remains intact is not a serious engineer.
Kind regards
Heiwa
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You are not a serious engineer, as you are incapable of calculating the energies involved. Real engineers, on the other hand, have done so, refuting your erroneous conclusions.
Just out of curiosity, explain for us the difference between the planes hitting (instead of the floors they actually hit) a) the very top floor, b) floors roughly in the middle of the buildings, and c) floors near the bottom of the buildings.
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So Apollo20 is Mr Greening? or Bazant? Which one? Anyway, nice to meet you at JREF forum.
So what do you think about my article at http://heiwaco.tripod.com/nist3.htm ?
Still convinced that the WTC 1 upper block is indestructible until push-up?
I list 7 conspiracy theories incl. that one in my paper that you adhere to. Can you explain that?
Can you provide any evidence that the upper block is still intact before the destruction below starts?
All videos I look at show the upper block selfdestructing before anything happens to the lower structure. It means that my scenario with the lower structure columns slicing the upper block floors doesn't even start.
Anyway, a collapse analysis must consider that there are many sub-parts of the structures invoved, each with is PE, KE and SE. In the WTC 1 case you must consider that the upper/lower columns will slice the lower/upper floors, the floors will hinge and drop on one another, etc. The columns will never hit one another. Plenty of local failures energy may be released but it will all be consumed by the same local failures and other failures, friction between all loose floors, etc. and every collapse is arrested. Two of the upper block walls should shear off the upper block and drop down, and so on. The assumption of a rigid, solid, upper block with uniform density, that is indestructible during push down is pure fantasy.
How to do the calculations are outlined in my paper and ref [4] there.
Kind regards
Heiwa
Newtons Bit
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Dr. Greening. He has a Ph.D. Give the man a little bit of respect for his hardwork.