Slartibartfast, it might be helpful if you made your point first, and then we can go back and pick it out step by step. I would still let you lead the discussion, but I might be less defensive in my answers if I knew where you were going. It's also the way scientific papers and discussions are organized, as well as legal ones. It's also a courtesy.
The properties of rubble. How it moves and how it behaves when encountering resistance, as compared to an intact block of storeys. Because it is in many different pieces, i.e., not held together by anything, rubble "falling" on top of a building will mostly flow over and outside it, not through it, except perhaps for some larger chunks. Rubble also cannot stay vertical as a mass for any significant length of time. The top of the rubble pile always flows down to the sides. That darn gravity again.
Slartibartfast, it might be helpful if you made your point first, and then we can go back and pick it out step by step. I would still let you lead the discussion, but I might be less defensive in my answers if I knew where you were going. It's also the way scientific papers and discussions are organized, as well as legal ones. It's also a courtesy.
The two main concepts in physics relevant to the collapse are momentum and kinetic energy. You seem hesitant to allow that two things moving at the same speed with the same mass have the same kinetic energy - this is a problem since momentum is only part of the story. I'm just trying to establish a context of how momentum and kinetic energy work so that we can both argue our theories within that context. That's all - I just don't find a discussion where there is no agreement on basic physics very interesting and I don't think that a reasonable discussion about crush-down/crush-up can be had without that agreement regarding the physics in play. I don't have time right now, but I'll answer your other posts later.
Much of the debris is in the form of dust, as we can see by the dust plumes in the pictures and that then covered Manhattan for days afterward, and as evidenced by the absence of larger chunks of matter at Ground Zero that one would normally find in natural collapses. That dust did settle of course, but it was not part of the "falling" debris that you are trying to include in this discussion of mass, and I don't think there has been an accurate estimate of how much of the buildings were converted into this dust, or what I like to call powder. Just sayin'.
Great. Provide any technical definition fo what "large amounts" are. How big as a % of the buildings mass? See... statements like "large amounts" are insufficient for any technical/scientific discussion.
This would be meat and drink to Heiwa, the banned Swedish Naval Architect, structural damage analyst and sometime advisor to the UN who swept all before him here on the jref prior to his banning.
'' Here iis a random link to his thread 'wWhy a one-way crush down is not possible ''
Much of the stuff that is being argued here is covered there too I think in case anyone wants to leaf through it for info .
This would be meat and drink to Heiwa, the banned Swedish Naval Architect, structural damage analyst and sometime advisor to the UN who swept all before him here on the jref prior to his banning.
'' Here iis a random link to his thread 'wWhy a one-way crush down is not possible '' ...
Heiwa? His work was called nonsense and delusional in a real engineering journal. You like delusions, no wonder you fall for the insanity of Heiwa's lies and moronic work.
I've watched your impressive (if ultimately futile) effort here, and thought that I would give it a try (I might be a noob, but I've got a little game... )
The properties of rubble. How it moves and how it behaves when encountering resistance, as compared to an intact block of storeys. Because it is in many different pieces, i.e., not held together by anything, rubble "falling" on top of a building will mostly flow over and outside it, not through it, except perhaps for some larger chunks. Rubble also cannot stay vertical as a mass for any significant length of time. The top of the rubble pile always flows down to the sides. That darn gravity again.
Yeah, but in order to flow down and to the sides, something has to change those velocity and momentum vectors off to the sides. Impacts with the top of the intact lower portion might work, as well as impacts with other pieces of rubble sitting on it. Either of those, however, will result in some amount of energy ending up in that intact top floor of the lower portion. Enough of that, and that floor will fail and drop everything, even if some of the rubble has been deflected off to the side. Then that floor's mass gets added to the rubble pile falling on the floor below, which may make up for the mass lost off to the sides while it was failing.
Your argument is, if I understand it correctly, that enough mass would have been deflected off to the sides to create a net reduction in the mass striking the floors below, and that this reduction would have happened at a quick enough rate to have saved most of the lower portion of the building, assuming nothing but gravity. I admit I am taking posters such as Almond at their word on this, but the impression I have got from reading this thread is that the numbers defining the building's strength and the force imparted by the rubble do not support that idea at all. Do your calculations indicate otherwise and/or why should I believe yours instead of the others?
It's a *********** rubble pile. I can't believe this is actually being taken as a serious argument.
Your argument is, if I understand it correctly, that enough mass would have been deflected off to the sides to create a net reduction in the mass striking the floors below, and that this reduction would have happened at a quick enough rate to have saved most of the lower portion of the building, assuming nothing but gravity.
My argument is that rubble sitting on top of a building cannot crush it. This is kindergarten-level understanding.
I admit I am taking posters such as Almond at their word on this, but the impression I have got from reading this thread is that the numbers defining the building's strength and the force imparted by the rubble do not support that idea at all. Do your calculations indicate otherwise and/or why should I believe yours instead of the others?
I have not seen any numbers on the force imparted by the rubble. Nor would I care, except to see who is willing to risk their career in claiming such utter nonsense.
My bowling ball argument is based on reality. How the impact from the bowling ball refers through the person's body to the ground is irrelevant to the point I was making. The bowling ball falling on someone's head clearly will fracture their skull. The fragments of bowling ball will not. There is no unconsidered factor here. If there is, please identify it specifically.
So then again you state that a 10lbs of debris will not fracture someones skull whereas a 10lbs intact bowling ball will. Is that correct?
I bet that makes people who are working with sand, snow and water very happy... especially those who work with thousands of pounds of it at a time becaue those are small fragments... and hence (in your world) incapable of hurting or killing them.
Have you notified the proper engineering channels of your discovery?
(how was that car crushed again? You have never answered)
I already pointed out where energy is lost in the system. To say that it was only converted into "heat" and "sound" is too stupid to comment to. Do civil engineers not have to know any physics? I don't think you're an engineer. If you are, you are knowingly lying.
Then I'm sure you can show how much energy was lost to the system. I'm sure you can show with math the amount of debris which did not impact the towers and was ejected outwards and how that loss of mass changed the dynamics enough to arrest the collapse.
I've actually found that the insults tossed at me tend to suggest that I don't understand the very principles that, in fact, debunk the official collapse hypothesis. It must be some new kind of 21st century newspeak (or maybe it's just old) to insist that the "debunker" understands something he/she clearly doesn't, and that the opponent, who clearly and demonstrably does understand, "doesn't". I know it's cliche to say it, but it is an Orwellian experience trying to debate "debunkers".
Then you can easily point me to any peer reviewed engineering or physics papers ANYWHERE IN THE WORLD, IN ANY LANGUAGE which states that NIST is wrong. Even that portions of NIST are wrong.
Please provide one. Just one.
I'm not asking for much. (hell I have 4 peer reviewed journal articles on my CV...)
Much of the debris is in the form of dust, as we can see by the dust plumes in the pictures and that then covered Manhattan for days afterward, and as evidenced by the absence of larger chunks of matter at Ground Zero that one would normally find in natural collapses. That dust did settle of course, but it was not part of the "falling" debris that you are trying to include in this discussion of mass, and I don't think there has been an accurate estimate of how much of the buildings were converted into this dust, or what I like to call powder. Just sayin'.
Here's an estimate on the distribution of sizes of concrete particles, according to Dr. Greening, for a 10x10x10cm cube of concrete impacted at the energies estimated from the collapse:
10cm-1cm: 30%
1cm-1mm: 20%
1mm-100μm: 15%
100μm-10μm: 10%
Less than 10μm: 25% Source
I think you will agree that only the smaller particles would have it easier to escape due to air pressure. The bigger ones would have more difficulty to escape that quickly due to their inertia at a minimum.
Now it would just be a baseless claim to say that most of the rubble spilled outside the towers' footprint. If, say, half of the rubble stood within it, then there would have been more than enough mass to crush the rest of the building, then turning more of it into rubble which couldn't escape that easily at first.
But you haven't yet addressed the point that in the demolitions I showed you the top falls basically intact, as Bažant predicted, so why should the WTC towers' top sections turn completely into rubble *before* starting to crush down, contradicting what is actually seen in the videos? So far your only argument has been your own belief, while Bažant proves his point using sound physics arguments and math.
The properties of rubble. How it moves and how it behaves when encountering resistance, as compared to an intact block of storeys. Because it is in many different pieces, i.e., not held together by anything, rubble "falling" on top of a building will mostly flow over and outside it, not through it, except perhaps for some larger chunks. Rubble also cannot stay vertical as a mass for any significant length of time. The top of the rubble pile always flows down to the sides. That darn gravity again.
I got news for you. Debris is not a fluid. Neither is dust. See the difference in this video:
These are mountains of dustified concrete and soil. They don't spread along the whole floor as a fluid would do. Debris has much more difficulty to flow than fluids, because it's not a fluid. Ultimately it settles and ceases flowing far before a fluid would.
The time needed for the dust to leave the footprint (not the heavier parts, e.g. the core columns that failed and stayed within the footprint or the steel plates and trusses of the flooring system, of which little were seen flying outside, if any, or the heavier pieces of concrete from the floors, of which there were large chunks visible on the surface of the rubble pile) would be compensated by the speed at which rubble was generated (110 floors in, say, at most 22 seconds is about 5 floors a second; the faster the collapse speed the faster the rubble was generated). Your argument that "[r]ubble also cannot stay vertical as a mass for any significant length of time" is thus moot.
So, you'd need a credible argument if you want to state that the rubble left the building before being able to crush it. So far you've just stated a belief, which is contradicted by every piece of evidence, e.g. the "crush-up" prior to "crush-down" did not happen as anyone can see, besides the fact that physics predicts it wouldn't happen.
As for your argument that rubble is just a collection of individual parts that together can't damage a structure more than each individual part by itself, you've already been indicated how wrong you are. As a reminder, the rubble on the front of the collapse was driven by the weight of the rubble which was right over it and remained there, which was a significant part, if only due to the laws of inertia. What you see being ejected is mostly dust (which doesn't account for more than 50% of the existing concrete) and the perimeter panels (which were "peeled off"). The building was more than that though.
Didn't Greening estimate that there was 120,000 tons of dust in the streets afer the collapses ? Say 400 tons from each floor of both Twin Towers. That's a very considerabe reduction in mass all on its own.Then there was almost no wire mesh reinforcing matting of which there were two layers in each floor. That's 9.2 million square feet per Tower that's also missing. Then there is 4.5 million square feet of floor decking per Tower that does not appear in the rubble. Core columns ?....there should be 10 MILES of them....massive core columns that are also largely missing. Concrete ? Hardly enough to make a decent rockery. Sure the centre of the footprint ogf WTC1 was virtually bare.
Didn't Greening estimate that there was 120,000 tons of dust in the streets afer the collapses ? Say 400 tons from each floor of both Twin Towers. That's a very considerabe reduction in mass all on its own.Then there was almost no wire mesh reinforcing matting of which there were two layers in each floor. That's 9.2 million square feet per Tower that's also missing. Then there is 4.5 million square feet of floor decking per Tower that does not appear in the rubble. Core columns ?....there should be 10 MILES of them....massive core columns that are also largely missing. Concrete ? Hardly enough to make a decent rockery. Sure the centre of the footprint ogf WTC1 was virtually bare.
Now it would just be a baseless claim to say that most of the rubble spilled outside the towers' footprint. If, say, half of the rubble stood within it, then there would have been more than enough mass to crush the rest of the building, then turning more of it into rubble which couldn't escape that easily at first.
I didn't know Bazant made predictions about demolitions.Why wouldn't he just ask demolitioners? What else does he predict? How long he'll remain employed at Northwestern?
I got news for you. Debris is not a fluid. Neither is dust. See the difference in this video:
As for your argument that rubble is just a collection of individual parts that together can't damage a structure more than each individual part by itself, you've already been indicated how wrong you are. As a reminder, the rubble on the front of the collapse was driven by the weight of the rubble which was right over it and remained there, which was a significant part, if only due to the laws of inertia.
Ah yes I remember now . Maybe you should talk to people that were actually there before you talk about "missing" material. I know you've seen pictures that disprove your "thoughts" so I won't go there.
Ah yes I remember now . Maybe you should talk to people that were actually there before you talk about "missing" material. I know you've seen pictures that disprove your "thoughts" so I won't go there.
I trust pictures a lot more than I trust people whe it comes to 9/11 DGM. Especially early pictures where they may have been revealing more than they knew.
Do you have any panoramic photos of the rubble pile in the footprint of WTC1 ? No closeups Wide or panoramic shots only.
I trust pictures a lot more than I trust people whe it comes to 9/11 DGM. Especially early pictures where they may have been revealing more than they knew.
Do you have any panoramic photos of the rubble pile in the footprint of WTC1 ? No closeups Wide or panoramic shots only.
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Which falls to the ground faster, Mr. Civil Engineer?
