posted by the paranoid delusional Scheister
The obvious lack of decency shown by use of "guest" sock puppets shows Faux' obvious disinterest in anything approaching "the truth."
<br>QUOTE (-> | QUOTE | posted by the paranoid delusional Scheister
The obvious lack of decency shown by use of "guest" sock puppets shows Faux' obvious disinterest in anything approaching "the truth."
<br>Originally posted by Guest -
Wrong, I'm not Foxx.
And what's with this "it" business??? It that "it" as in "it rubs the lotion on its skin, or it gets the hose again". Smacks of Hannibal Lector's buddy...going to make a costume out of old Foxx?? I know that fox' fur is nice , but that's a little extreme...
<br>RE: Near Free-fall speeds...
| QUOTE | Originally posted by Foxx on page 74
Scheister has been emphasizing the fact that the towers did NOT fall at free-fall speeds since he first started posting in this thread (something that most of us already know and agree).
<br>Scheister reply ... "Well, you sure didn't when I started- and implying you did is, now wait for it, another lie. Keep runnin your mouth, a**hole, every time you open it I get more ammo. You just can't help yourself.
QUOTE (-> | QUOTE | Originally posted by Foxx on page 74
Scheister has been emphasizing the fact that the towers did NOT fall at free-fall speeds since he first started posting in this thread (something that most of us already know and agree).
<br>Scheister reply ... "Well, you sure didn't when I started- and implying you did is, now wait for it, another lie. Keep runnin your mouth, a**hole, every time you open it I get more ammo. You just can't help yourself.
Originally posted by Foxx on page 12
"Schneidster has added his .02 cents worth to the discussion of whether or not it was possible through physics that the buildings could have realistically fallen at near the rate of free-fall....
Personally, I believe that Andrew Johnson is correct in his basic physics... that given 'resistance' to the upper falling mass by the uncompromised materials and structure below, the buildings could not have 'collapsed' at near the rate of free-fall."
<br>Again, just as I did the first time I mentioned the fall rate, I stated... "the towers did NOT fall at free-fall speeds"
I have always from the beginning stated the buildings fell at NEAR free-fall speeds NOT AT 'free-fall' speeds.
You have me confused with someone else, Scheister...
...just as you are 'confused' (let's call that paranoid delusional) for your continual false allegations and lies that everyone under the sun is some sock-puppet invention of mine.
As I've already stated numerous times, I do not have any need for NOR DO I EVER utilize 'sock-puppets'... (unlike you with your alter-ego "CHUCKLES", whom you employ to boost your own ego).
How many more people are you going to accuse of being me? You've now accused a number of people, who have turned around and point blank told you that you are delusional. Don't you ever get tired of being wrong.
You have serious emotional problems, Scheister. Get help.
Schneibster
29th November 2005 - 08:13 AM
I got only one problem, Faux, and that's having to look at your sorry excuses for posts. You dig up something from twenty pages downstream from where the argument originated, after you got pwn3d, and now it's "I always didn't believe that..."
Whatever. Keep lying, dips**t. Honest to jeebus, I never thought I'd actually see someone dig a hole with his mouth.
Foxx
29th November 2005 - 08:23 AM
QUOTE (Schneibster+Nov 29 2005, 08:13 AM)
Whatever. Keep lying, dips**t. Honest to jeebus, I never thought I'd actually see someone dig a hole with his mouth. Heh - take a look in the mirror, Scheister. You are doing it every time you open yours.  BTW - another one of your lies and paranoid delusions... I have never posted personal information about you or anyone else. Look back a few pages... you opened your mouth and someone else dug up the 'personal info' on you that... rather than being some 'quantum physics professor' you are nothing more than a 'computer guy' who thinks he's a quantum physics professor (amongst other things). Don't blame me for that. Again, look in the mirror. When you recognize that you are doing it to yourself, and making yourself look like an idiot, trundle on down to get some counselling. Also, no one is forcing you to read my posts. Who is doing that to you? I suppose you want to accuse me of that also? Get help before you fall off the cliff, have a tantrum, and start beating on your monitor. Idiot !
metamars
29th November 2005 - 08:25 AM
QUOTE Are you real, real sure you want to go here? What are you going to do when I post a link to the post that shows you're lying? Are you catching whatever it is Faux has, or did you have it already? You explained NOTHING. YOU didn't even understand why the picture showed what you were saying couldn't be true until it had been explained to you five times. And I can prove THAT, too. It's all right there, in black and white. Next time, actually take the trouble to remember what was said before you stick your foot in your mouth any more. <br>Gee whiz, Schneibster, you seem to be saying that not only am I not recalling correctly, but that I am lying when I say that "I may be wrong". Lying implies intentionality, but hey, don't let such fine points cramp your style. Your eagerness to accuse others of lying is quite evident to anybody who has read even a portion of your posts. Not that your ad hominem attacks stop at accusations of lying. So, go ahead, post a link that "to the post that shows you're lying?" And also, explain why "the picture showed what you were saying couldn't be true until it had been explained to you five times" But before you do that, why don't you explain why the conservation of momentum calculation that I referred to is of such little interest to you? Is that why I'm now being added to your "liar's list"? So that you can deflect attention from the significance of this analysis? I find it interesting that, once again, you don't eagerly seize on the opportunity to encourage people reading this thread to take a quantitative analysis (or suggestion of same) to the sorts of people that can easily determine whether it's nonsense or not. Apparently, you can think of no higher or more worthy authority than yourself. If so, you are indeed a physorg.com 'pope'. No other authority is necessary. If anybody reading this thread finds it tiresome that Schneibster would spam it, once again, with accusations of lying, may I suggest printing out the Hoffman, Steven E. Jones, and Trumpman papers, plus my conservation of momentum post on page 73 of this thread (if a worked out calculation cannot be found) and taking these to a college near you and getting Ph.D. physicists, engineers, and applied mathematicians to take a look. Of course, we are not interested in hand-waiving by these gents, but rather solid, specific confirmation, refutation, and/or criticism. Certainly, any such professor who merely says "this is crap" or "this is lying" or some such without saying why is not contributing anything. Hopefully, you will not run into any such folks, but if so, there are always others you can ask. Oh, and I remind the readers of this thread that Schneibster has accused Foxx of lying (ad infinitum, ad ad nauseam) because he used, and continues to use, the phrase "near free-fall speed". However, BYU Physics Professor Steven E. Jones also describes the collapses this way (as do I ). Logically, Schneibster must also view Professor Steven E. Jones as a liar. If so, I find myself in good company, indeed. I'll take the 'lying' of a Steven E. Jones over the 'truth telling' of a Schneibster any day. Especially a Steven E. Jones that presents in front of his peers, seeks to publish in a peer-reviewed book, and calls for a full, international inquiry by a great number of his peers. (Perhaps in Schneibster-Space, these veracities are reversed, and take their expected meaning. However, I prefer to limit my physics inquiries to the universe my professors referred to, back in the day.) Why Indeed Did the WTC Buildings Collapse? (By BYU Physic Professor Steven E. Jones)QUOTE (-> | QUOTE | Are you real, real sure you want to go here? What are you going to do when I post a link to the post that shows you're lying? Are you catching whatever it is Faux has, or did you have it already? You explained NOTHING. YOU didn't even understand why the picture showed what you were saying couldn't be true until it had been explained to you five times. And I can prove THAT, too. It's all right there, in black and white. Next time, actually take the trouble to remember what was said before you stick your foot in your mouth any more.
<br>Gee whiz, Schneibster, you seem to be saying that not only am I not recalling correctly, but that I am lying when I say that "I may be wrong". Lying implies intentionality, but hey, don't let such fine points cramp your style. Your eagerness to accuse others of lying is quite evident to anybody who has read even a portion of your posts. Not that your ad hominem attacks stop at accusations of lying.
So, go ahead, post a link that "to the post that shows you're lying?" And also, explain why "the picture showed what you were saying couldn't be true until it had been explained to you five times"
But before you do that, why don't you explain why the conservation of momentum calculation that I referred to is of such little interest to you? Is that why I'm now being added to your "liar's list"? So that you can deflect attention from the significance of this analysis?
I find it interesting that, once again, you don't eagerly seize on the opportunity to encourage people reading this thread to take a quantitative analysis (or suggestion of same) to the sorts of people that can easily determine whether it's nonsense or not. Apparently, you can think of no higher or more worthy authority than yourself. If so, you are indeed a physorg.com 'pope'. No other authority is necessary.
If anybody reading this thread finds it tiresome that Schneibster would spam it, once again, with accusations of lying, may I suggest printing out the Hoffman, Steven E. Jones, and Trumpman papers, plus my conservation of momentum post on page 73 of this thread (if a worked out calculation cannot be found) and taking these to a college near you and getting Ph.D. physicists, engineers, and applied mathematicians to take a look. Of course, we are not interested in hand-waiving by these gents, but rather solid, specific confirmation, refutation, and/or criticism.
Certainly, any such professor who merely says "this is crap" or "this is lying" or some such without saying why is not contributing anything. Hopefully, you will not run into any such folks, but if so, there are always others you can ask.
Oh, and I remind the readers of this thread that Schneibster has accused Foxx of lying (ad infinitum, ad ad nauseam) because he used, and continues to use, the phrase "near free-fall speed". However, BYU Physics Professor Steven E. Jones also describes the collapses this way (as do I ). Logically, Schneibster must also view Professor Steven E. Jones as a liar.
If so, I find myself in good company, indeed. I'll take the 'lying' of a Steven E. Jones over the 'truth telling' of a Schneibster any day. Especially a Steven E. Jones that presents in front of his peers, seeks to publish in a peer-reviewed book, and calls for a full, international inquiry by a great number of his peers.
(Perhaps in Schneibster-Space, these veracities are reversed, and take their expected meaning. However, I prefer to limit my physics inquiries to the universe my professors referred to, back in the day.)
Why Indeed Did the WTC Buildings Collapse? (By BYU Physic Professor Steven E. Jones)
How do the upper floors fall so quickly, then, and still conserve momentum in the collapsing buildings? The contradiction is ignored by FEMA, NIST and 9-11 Commission reports where conservation of momentum and the fall times were not analyzed. The paradox is easily resolved by the explosive demolition hypothesis, whereby explosives quickly remove lower-floor material including steel support columns and allow near free-fall-speed collapses (Harris, 2000).
Schneibster
29th November 2005 - 08:28 AM
Hee hee, "thinks he's a quantum physics professor." Now I hate to say it, but friend, a primary reason your *** is weak is because I actually know how quantum mechanics works, or at least as much as I've been able to absorb from a bunch of books written by the smartest minds around that have worked on it. But I don't confuse what I know with what a professional physicist knows about quantum mechanics, not ever, not once. So here you are, lying again. Like I said, you just can't resist.
metamars
29th November 2005 - 09:55 AM
| QUOTE | Exactly correct, metamars. This is what 'these people' are somehow missing. Scheister has been emphasizing the fact that the towers did NOT fall at free-fall speeds since he first started posting in this thread (something that most of us already know and agree).
Those of us who point to the fact that they fell at 'near' free-fall speeds (as evidence of controlled demolition) recognize that in order to do so, there must be next-to-no resistance provided by the lower portion of the fire-unaffected (still sound) column structure below.
<br>
The problem with the statement "there must be next-to-no resistance..." is that, while it's a reasonable qualitative statement, it's not quantitative enough. Especially when you compare the more reaslistic collapse time of 12 - 16 seconds. That is, at the outside, almost double the free fall time. This is still "near", from your perspective, my perspective, and Steven E. Jones' perspective, but the real question is, "is it near enough?"
What's exciting about the conservation of linear momentum calculation is that, assuming no (structural) resistance, you get almost exactly the speed of collapse observed. Since there is still a .5 second or so "lag", a skeptic might still raise the question "is it near enough"? I believe that even civil engineers (as opposed to "merely" physicists, say) would mostly agree that this is indeed "near enough" to indicate CD.
However, as I have complained bitterly about relying on even the collective intuition of NIST engineers to provide a belief in the "local collapse always grows into a global collapse" credo, I cannot say that we can all of a sudden consider their collective intuition re the conservation of momentum calculation to constitute proof.
However, as a means of piqueing the interest of engineers who can look more deeply into the issue, I believe this approach is superlative. For one thing, they may indeed do a calculation along the lines I indicated (adding columns), and get a result that is quantitative enough for them to conclude what you and I believe.
It may also be possible to eliminate the .5 second lag by taking air resistance into account.
Even doing that, though, at the end of the day I don't believe civil engineers will be completely convinced without significant computer modeling. Thus, the need to argue convincingly that it's necessary.
adoucette
29th November 2005 - 02:28 PM
QUOTE (metamars+Nov 29 2005, 01:37 AM)
To conceptualize what Heller is talking about: imagine cutting each tower into slices 1 floor thick, from the collapse zone on down. (Above the collapse zone, there is no need to do this.) Further, imagine shrinking the height of each floor down to an infinitesimally small value. Pretend that a set of giant claws are holding each floor in place, at it's proper height, but that each claw releases it's floor a split second before the mass falling on top of it hits it. Thus, there is no upward force being considered due to columns, diagonal supports, etc. AT ALL.
So basically, the algorithm is as follows (Assuming collapse initiation at floor 73):
Take the mass of floors 73 through 111 (call this m(Sum(39)), and calculate the downward momentum after falling through a single floor. You certainly can easily calculate the downward velocity at impact and the time interval required for this first impact to occur. Call them v0 and t0
At height = 72 floors, by conservation of momentum, the total downward momentum a split second before impact:
p(m(Sum(39))) ( p is standard nomenclature for momentum )
must equal the total downward momentum after impact:
p(m(Sum(39))) + p(m(Floor 72))
But this is just
p(m(Sum(40))) (i.e, the momentum of the top 40 floors)
(Note that one of the assumptions of this calculation is that the masses "stick together", i.e., they do not bounce. The collision is inelastic. This is favorable to the FEMA Fairy Tale, plus makes the math easy :-) )
Since you know p(m(Sum(40))), and since you know m(Sum(40)), you very easily can determine the new downward velocity of the combined mass right after this first impact (of course, it will be less than the downward velocity of m(Sum(39)) just before impact)
Using these values, you basically iterate the process sketched out above.
You end up with a set of time intervals, t0, t1, t2, ... t71 such that when you add them up, you get the total time of collapse.
Well, ain't it amazing, but apparently when Hoffman did this calculation, it just so happens that you get almost exactly what was observed. Thus, the statement that "the buildings collapsed almost as though the frames didn't exist" is correct.
The sum of t0 to t71 will equal free fall time plus the slowing caused by R0 to R71 where Rn is the resistance time of each floor to the fall. We don't know what the Rn values are but considering the MOMENTUM of the fall, i.e. MASS X VELOCITY, one can pretty quickly realize that R is going to be, at most, a small fraction of a second. What's more, both M and V increase on the way down, so while Rn increases as n gets smaller, the MOMENTUM also increases, thus preserving the sub-second collapse time. Rn values between 3/100s up to as high as 7/100s of a second would allow for the collapse to occur within the various reported time frames for the collapse. Those R values seem reasonable to me, based on the massive overload of the falling mass. Arthur
adoucette
29th November 2005 - 03:04 PM
Further analysis of the picture of WTC 7  Note that the pedestrian bridge is over the promenade. Note that this is NOT a street. Now look at the aerial view of this area.  West Broadway separates WTC 7 from the Post Office. It would appear that the street sign you see in the distance is the West Broadway sign, which means the damage you see, as well as the fires are in the WTC 5 & 6 building and not the WTC 7 building. The photographer has his back to the WTC 7 building. This is consistant with the aerial depiction of the fact that the pedestrian bridge originates between WTC 5 & 6 and is not attached to either, as well as the promenade that runs in front of both buildings. If this was WTC 7, then note that the WTC 7 building is set back compared to the Post Office, and so you would have an obvious view of the long face of the Post Office in the right of the picture. The two buildings are on the same plane, thus this also indicates this is not WTC 7 and the Post Office. Arthur
metamars
29th November 2005 - 03:21 PM
| QUOTE | The sum of t0 to t71 will equal free fall time plus the slowing caused by R0 to R71 where Rn is the resistance time of each floor to the fall.
<br>Errr, uhmm, you didn't define "resistance time", nor explain how it relates to the calculation that I sketeched out, nor actually calculated anything.
I believe you can actually do this calculation if you make a serious effort......
QUOTE (-> | QUOTE | The sum of t0 to t71 will equal free fall time plus the slowing caused by R0 to R71 where Rn is the resistance time of each floor to the fall.
<br>Errr, uhmm, you didn't define "resistance time", nor explain how it relates to the calculation that I sketeched out, nor actually calculated anything.
I believe you can actually do this calculation if you make a serious effort......
Those R values seem reasonable to me, based on the massive overload of the falling mass.
<br>See above.
adoucette
29th November 2005 - 04:38 PM
QUOTE (metamars+Nov 29 2005, 03:21 PM) | QUOTE | The sum of t0 to t71 will equal free fall time plus the slowing caused by R0 to R71 where Rn is the resistance time of each floor to the fall.
<br>Errr, uhmm, you didn't define "resistance time", nor explain how it relates to the calculation that I sketeched out, nor actually calculated anything.
I believe you can actually do this calculation if you make a serious effort......
QUOTE (-> | QUOTE | The sum of t0 to t71 will equal free fall time plus the slowing caused by R0 to R71 where Rn is the resistance time of each floor to the fall.
<br>Errr, uhmm, you didn't define "resistance time", nor explain how it relates to the calculation that I sketeched out, nor actually calculated anything.
I believe you can actually do this calculation if you make a serious effort......
Those R values seem reasonable to me, based on the massive overload of the falling mass.
<br>See above. Actually I did define it, but I don't know what the actual times would be. They wouldn't be the same for each floor as the resistance of the core structure increases as you go down and the momentum of the falling mass increases, these two would interact to produce the Rn time for each floor. Since acceleration increases based upon the square of the time I would also presume that the Momentum would most likely increase faster than the resistance.
As you said, without a incredibly complex computer simulation estimating these values appears impossible.
However one can do, as I did, and estimate the range of Rn values based on the observed collapse time. Thus I figure Rn values in the range of 0.03 to 0.07 of a second would work.
The logical question then is 'Do these Rn values seem reasonable?".
They do to me.
Arthur
Guest
29th November 2005 - 05:04 PM
What might "seem reasonable" to adoucette flys in the face of reason to most.
An example - when asked what caused the molten metal beneath the buildings adoucette offers smouldering fires. Reason and science tells most that to reach any degree of temperature fires need oxygen. In the case of the WTC, which had a million tons or more of dust and rubble atop the fires - more than enough to extinguish even raging fires - and the continous pouring of water by the fire department, it is a peculiar form of reasoning that adoucette displays.
Nothing unusual for adoucette et al - when the reasoning employed MUST result in backing the official story just what we have come to expect.
Can I ask those more familiar with the workings of such matters - would you expect the Professor Jones paper, after peer review, to have the effect those of us in the September 11 truth camp are fervently hoping? Will the mainstream press be forced to ackowledge it?
metamars
29th November 2005 - 05:43 PM
| QUOTE | Actually I did define it, but I don't know what the actual times would be.
<br>Well, I suppose in a way you did define it, though if you actually did the specific calculation I sketched out, you wouldn't calculate this. Also, it doesn't provide any insight (that I can see). And that is because the effect of crashing through the floors is cumulative. Thus, while it might be of interest to calculate the net "resistance time" at any particular point in the collapse, your baseline would have to be the start of the collapse.
Put another way, if Uncle Bob beat you driving to Aunt Matilda's home for Thanksgiving dinner in New York, this should not amaze you merely because Uncle Bob drove an average of 40 mph, while you drove 30 mph. It also depends on when Bob left his home, and how far his home is from Aunt Matilda's, as compared to these parameters in your case.
Even more serious, though, is the fact that you are just guessing at the values of Rn, not based on any physics at all.
QUOTE (-> | QUOTE | Actually I did define it, but I don't know what the actual times would be.
<br>Well, I suppose in a way you did define it, though if you actually did the specific calculation I sketched out, you wouldn't calculate this. Also, it doesn't provide any insight (that I can see). And that is because the effect of crashing through the floors is cumulative. Thus, while it might be of interest to calculate the net "resistance time" at any particular point in the collapse, your baseline would have to be the start of the collapse.
Put another way, if Uncle Bob beat you driving to Aunt Matilda's home for Thanksgiving dinner in New York, this should not amaze you merely because Uncle Bob drove an average of 40 mph, while you drove 30 mph. It also depends on when Bob left his home, and how far his home is from Aunt Matilda's, as compared to these parameters in your case.
Even more serious, though, is the fact that you are just guessing at the values of Rn, not based on any physics at all.
As you said, without a incredibly complex computer simulation estimating these values appears impossible.
<br>I never said an "incredibly" complex computer "simulation". Neither is the case.
To do this calculation by hand would take something like an hour (barring mathematical shortcuts), and it would be very boring, involving 73 iterations of basically the same process. To program on a computer would take something like half an hour, and at least be mildly entertaining.
In fact, I will eventually do exactly that, if nobody can find a solid reference that I would think is already in cyberspace.
| QUOTE |
However one can do, as I did, and estimate the range of Rn values based on the observed collapse time. Thus I figure Rn values in the range of 0.03 to 0.07 of a second would work.
The logical question then is 'Do these Rn values seem reasonable?".
They do to me.
<br>See above.
adoucette
29th November 2005 - 05:44 PM
QUOTE (Guest+Nov 29 2005, 05:04 PM) What might "seem reasonable" to adoucette flys in the face of reason to most.
An example - when asked what caused the molten metal beneath the buildings adoucette offers smouldering fires. Reason and science tells most that to reach any degree of temperature fires need oxygen. In the case of the WTC, which had a million tons or more of dust and rubble atop the fires - more than enough to extinguish even raging fires - and the continous pouring of water by the fire department, it is a peculiar form of reasoning that adoucette displays.
Nothing unusual for adoucette et al - when the reasoning employed MUST result in backing the official story just what we have come to expect.
Well I posted what I believe and how I came up with it. I suspect others will make up their own minds as to the logic of my calculations and what is reasonable or not. As to the "molten metal", seems there is scant evidence for same. Eventually the metal would have cooled and solidified, but I've yet to see a picture of them hauling a big hunk of solid metal out of that pile. Got one? As to how long fires burn, well the debris pile was certainly not airtight, and thus air could reach a fire burning down below. Secondly a fire CREATES a draft, drawing air to it. Third, if it is burning within the pile, getting water ONTO it is problematic, regardless of how much you pour onto the pile. Water has surface tension and will follow girders and such away from where you put it. Thirdly, a long burning fire will raise the temp of the materials above it such that much of the water will vaporize on the way down. This raised temp can extend quite a way from the fire since the huge debris pile above it will work as an effective insultation layer. While this was the largest pile of debris ever, other rubble piles have had similar long burning fires, and if you check the details, you will find they can be difficult to put out. Arthur
metamars
29th November 2005 - 06:05 PM
| QUOTE | Can I ask those more familiar with the workings of such matters - would you expect the Professor Jones paper, after peer review, to have the effect those of us in the September 11 truth camp are fervently hoping? Will the mainstream press be forced to ackowledge it?
<br>The mainstream press will be the last entity on the face of the Earth to acknowledge what really happened on 911. Even the US Government will admit the truth before them. 
Okay, this may not be quite right. But whether your name is Zelikow or Zuber, you are still a "Z" and during roll call, you will never have to sweat being called first.
The NY Times has still not acknowledged the truth of the JFK assassination, and that was 40 years ago. What on earth makes you think 911 will be any different?
The correct attitude toward the US media is "how soon can we put this whore out of business"?
To get the word out, you must, unfortunately, bypass the media. Not exactly what the Founding Fathers had in mind when they risked their lives for freedom, but that is the reality. Please deal with it.
In the mean time, please don't let the lack of MSM recognition which you will never get, anyhow,* deter you at all in any efforts to enlighten the technical community. Nobody knows how this will play out, but our duty not only as citizens of our own coutries, but as citizens of the world, is to do our best to bring accountability to government and disempower the war mongers, however we may perceive the best way to do that. There are babies being born in Iraq already with such gross birth defects as a "head growing out of it's head", almost certainly due to US depleted uranium munition poisoning. If that is not motivation enough to do your part, then I don't know what is.
* Heck, Schneibster will admit a mistake before this happens!
yesitdid
29th November 2005 - 06:39 PM
QUOTE (adoucette+Nov 29 2005, 03:04 PM) Further analysis of the picture of WTC 7 Note that the pedestrian bridge is over the promenade. Note that this is NOT a street. Now look at the aerial view of this area. West Broadway separates WTC 7 from the Post Office. It would appear that the street sign you see in the distance is the West Broadway sign, which means the damage you see, as well as the fires are in the WTC 5 & 6 building and not the WTC 7 building. The photographer has his back to the WTC 7 building. This is consistant with the aerial depiction of the fact that the pedestrian bridge originates between WTC 5 & 6 and is not attached to either, as well as the promenade that runs in front of both buildings. If this was WTC 7, then note that the WTC 7 building is set back compared to the Post Office, and so you would have an obvious view of the long face of the Post Office in the right of the picture. The two buildings are on the same plane, thus this also indicates this is not WTC 7 and the Post Office. Arthur omigosh , you could be right. I notice now that the picture L-23-b actually says it is WTC 7 and that the lower part of the face looks very different than that in 23-a. My mistake. Frankly the photo 23-b shows a greater extent of damage than does 23-a. No wonder that damaged columns are visible in 23-a given the extent of damage to #5 & 6.
yesitdid
29th November 2005 - 07:01 PM
Mass of 39 floors = 39m
velocity v=v(initial) + at
First drop, assuming free fall, the momentum of the top section will be
p(1) = 39m(at) ,, (initial velocity is zero)
Now the next floor collides inelastically with the 39 floor upper section and that will reduce the velocity(conservation of momentum)
p(1)=p(2)=40mv
where v is the velocity once the top 39 floors combines with the next floor
so
39m(at)=40mv
(39/40)(at)=v
at is the velocity in free fall of the upper section travelling 4 meters
4=0.5 at^2 = 0.5(9.8)t^2
t=0.904 seconds so at=9.8(0.904) = 8.85 m/s
(39/40)(8.85)=8.63 m/s
So in the fisrt collision as envisioned by this simplified accounting changes the velocity by
(8.85-8.63)/8.85 *100= 2.5%
In subsequent collisions the falling mass will increase while the individual floor mass remains the same. The initial velocity will no longer be zero and thus the velocity of subsequent collisions will be much greater than this one. therefore a 2.5% reduction in velocity is the single largest change due to these collisions and the further one goes the less significant the slowing gets.
Schneibster
29th November 2005 - 07:03 PM
Nicely done, yesitdid.
adoucette
29th November 2005 - 07:13 PM
QUOTE (metamars+Nov 29 2005, 05:43 PM) | QUOTE | Actually I did define it, but I don't know what the actual times would be.
<br>Well, I suppose in a way you did define it, though if you actually did the specific calculation I sketched out, you wouldn't calculate this. Also, it doesn't provide any insight (that I can see). And that is because the effect of crashing through the floors is cumulative. Thus, while it might be of interest to calculate the net "resistance time" at any particular point in the collapse, your baseline would have to be the start of the collapse.
Put another way, if Uncle Bob beat you driving to Aunt Matilda's home for Thanksgiving dinner in New York, this should not amaze you merely because Uncle Bob drove an average of 40 mph, while you drove 30 mph. It also depends on when Bob left his home, and how far his home is from Aunt Matilda's, as compared to these parameters in your case.
Even more serious, though, is the fact that you are just guessing at the values of Rn, not based on any physics at all.
QUOTE (-> | QUOTE | Actually I did define it, but I don't know what the actual times would be.
<br>Well, I suppose in a way you did define it, though if you actually did the specific calculation I sketched out, you wouldn't calculate this. Also, it doesn't provide any insight (that I can see). And that is because the effect of crashing through the floors is cumulative. Thus, while it might be of interest to calculate the net "resistance time" at any particular point in the collapse, your baseline would have to be the start of the collapse.
Put another way, if Uncle Bob beat you driving to Aunt Matilda's home for Thanksgiving dinner in New York, this should not amaze you merely because Uncle Bob drove an average of 40 mph, while you drove 30 mph. It also depends on when Bob left his home, and how far his home is from Aunt Matilda's, as compared to these parameters in your case.
Even more serious, though, is the fact that you are just guessing at the values of Rn, not based on any physics at all.
As you said, without a incredibly complex computer simulation estimating these values appears impossible.
<br>I never said an "incredibly" complex computer "simulation". Neither is the case.
To do this calculation by hand would take something like an hour (barring mathematical shortcuts), and it would be very boring, involving 73 iterations of basically the same process. To program on a computer would take something like half an hour, and at least be mildly entertaining.
In fact, I will eventually do exactly that, if nobody can find a solid reference that I would think is already in cyberspace.
| QUOTE |
However one can do, as I did, and estimate the range of Rn values based on the observed collapse time. Thus I figure Rn values in the range of 0.03 to 0.07 of a second would work.
The logical question then is 'Do these Rn values seem reasonable?".
They do to me.
<br>See above.
I have no idea how you could derive resistance time via any calculation we are capable of formulating.
Your formula, using momentum, implies a measure of velocity. How do you derive velocity at a per floor level unless you take resistance time into account?
i.e. No resistance than fall is simply acceleration under gravity (ignoring air resistance)
But of course there was resistance (even if, as they say, it was futile) so there would of course be some slowing down from free fall time. Thus I subtract from the no resistance fall time the resistance put up by each floor.
Assuming that the floors are the key to the slowing down time then your basic approach makes sense (though I suspect the buckling of the central core may have played a more important role in slowing the fall. I suspect the bolts and Truss seats holding the floor trusses simply sheared off, rather quickly, from the perimeter columns so that the floors probably played less of a roll than the central column. It was, in fact, their prime responsibility to handle gravity loads)
And as I have pointed out, I have no way to determine what the Rn times were, which is why I think you need a complex model to estimate it. All I showed was the Rn times appeared to have to fall within a RANGE of times for the collapse to work driven by gravity alone. After a little more thought I would amend that to be that the AVERAGE Rn times would have to fall within this range. For instance, the high Rns could be above this range and the last below it and still work.
Do you disagree with this logical assessment and if so why?
I may have paraphrased what you posted, but I thought that was what you were asking for here:
QUOTE (-> | QUOTE |
However one can do, as I did, and estimate the range of Rn values based on the observed collapse time. Thus I figure Rn values in the range of 0.03 to 0.07 of a second would work.
The logical question then is 'Do these Rn values seem reasonable?".
They do to me.
<br>See above.
I have no idea how you could derive resistance time via any calculation we are capable of formulating.
Your formula, using momentum, implies a measure of velocity. How do you derive velocity at a per floor level unless you take resistance time into account?
i.e. No resistance than fall is simply acceleration under gravity (ignoring air resistance)
But of course there was resistance (even if, as they say, it was futile) so there would of course be some slowing down from free fall time. Thus I subtract from the no resistance fall time the resistance put up by each floor.
Assuming that the floors are the key to the slowing down time then your basic approach makes sense (though I suspect the buckling of the central core may have played a more important role in slowing the fall. I suspect the bolts and Truss seats holding the floor trusses simply sheared off, rather quickly, from the perimeter columns so that the floors probably played less of a roll than the central column. It was, in fact, their prime responsibility to handle gravity loads)
And as I have pointed out, I have no way to determine what the Rn times were, which is why I think you need a complex model to estimate it. All I showed was the Rn times appeared to have to fall within a RANGE of times for the collapse to work driven by gravity alone. After a little more thought I would amend that to be that the AVERAGE Rn times would have to fall within this range. For instance, the high Rns could be above this range and the last below it and still work.
Do you disagree with this logical assessment and if so why?
I may have paraphrased what you posted, but I thought that was what you were asking for here:
I don't believe civil engineers will be completely convinced without significant computer modeling. Thus, the need to argue convincingly that it's necessary.
<br>I used the term complex based on what NIST did for their modeling of two KNOWN quantities, Plane and Tower. Modeling the collapse would include many more structural elements and a much wider range of unknowns, thus the COMPLEX part.
Arthur
adoucette
29th November 2005 - 07:28 PM
QUOTE (yesitdid+Nov 29 2005, 07:01 PM) Mass of 39 floors = 39m
velocity v=v(initial) + at
First drop, assuming free fall, the momentum of the top section will be
p(1) = 39m(at) ,, (initial velocity is zero)
Now the next floor collides inelastically with the 39 floor upper section and that will reduce the velocity(conservation of momentum)
p(1)=p(2)=40mv
where v is the velocity once the top 39 floors combines with the next floor
so
39m(at)=40mv
(39/40)(at)=v
at is the velocity in free fall of the upper section travelling 4 meters
4=0.5 at^2 = 0.5(9.8)t^2
t=0.904 seconds so at=9.8(0.904) = 8.85 m/s
(39/40)(8.85)=8.63 m/s
So in the fisrt collision as envisioned by this simplified accounting changes the velocity by
(8.85-8.63)/8.85 *100= 2.5%
In subsequent collisions the falling mass will increase while the individual floor mass remains the same. The initial velocity will no longer be zero and thus the velocity of subsequent collisions will be much greater than this one. therefore a 2.5% reduction in velocity is the single largest change due to these collisions and the further one goes the less significant the slowing gets. I considered this approach, but my logic was that the conservation of momentum would mean that the lower floor would gain the momentum lost by the falling mass. Thus the next floor would be hit by the same momentum as the previous floor plus the momentum gained over the next 12 ft, regardless of the loss of momentum to the upper section in the previous collision. Arthur
metamars
29th November 2005 - 09:18 PM
| QUOTE | Your formula, using momentum, implies a measure of velocity. How do you derive velocity at a per floor level unless you take resistance time into account?
<br>I will eventually do this calculation (using a computer program) and post the results. I don't have the time to teach you physics.
I will also post the program.
Of course, if anybody finds this out there in cyberspace, or has a half hour or so, feel free.
Schneibster
29th November 2005 - 09:36 PM
OK, quick analysis:
The impulse on the next lower floor is equal to the impulse on the stack of floors falling on it; Newton's Third Law, for every action (the impact) there is an equal and opposite reaction (the collapse).
Force is mass times acceleration; thus, due to these equal and opposite forces, the stack of floors accelerates upward (which we call deceleration, in non-technical terms, or negative acceleration in technical terms; in plain language, it slows down) and the single floor accelerates downward.
This means that if a stack of thirty-nine floors falls on one floor, then the stack of floors will have reduced its speed after the collision by some fraction of its speed before the collision, distributing momentum to the newly added floor; so that the struck floor takes on that new speed, and the falling mass slows slightly.
How much does the single floor accelerate? It accelerates to the speed of the already falling floors, minus the deceleration imposed by its resistance. How much does the falling mass decelerate? To answer this question, we turn to the principle of conservation of momentum. Since the single floor has zero velocity (not moving) before the impact, it must have zero momentum, since momentum is mass times velocity. After the collision, the momentum must be the same, but for a greater mass; thus, the velocity of the total mass must have decreased, since there is now more mass, but the same momentum. How much less? It's a simple ratio: the ratio of the new velocity to the old velocity must be the inverse of the ratio of the new mass to the old mass; this way, the product of the mass and velocity will be the same for both the old mass and velocity, and the new mass and velocity. A little algebra will show you that
m(new)/m(old) = v(old)/v(new)
implies that
m(new) x v(new) = m(old) x v(old).
So what is that ratio? It is simply
40 floors/39 floors.
Thus, the new velocity must now be 39/40 of what it was; that is, 1/40 less. 1/40 is 2.5%.
When the mass of 40 floors strikes the next floor down, it will decelerate again, to 1/41 of its velocity at impact; however, do not neglect the fact that it is subject to the acceleration of gravity, which will give it far more than the 1/40 it lost in the prior impact. So not only will the resistance of the next floor only slow the mass by 1/41 (2.44%, instead of the previous 2.5%), but the velocity will be much more than it was the last time (by 9.80665m/s^2 during the time/distance between the impact with the originally struck floor and the newly struck floor). Thus, the resistance of this new floor will be much less in terms of the momentum of the falling mass than the resistance of the originally struck floor. (It's not that it will be less resistance; it's that it will be far more force; but if we express the resistance as a percentage of the force, then the percentage will be far smaller due to both the continued acceleration and the greater mass).
As I have said many times on this thread, if the floor below the collapse didn't stop the falling building segment, no floor below that one had any chance at all, as the momentum increased due to the force of gravity, and due to the addition of more and more floors to the falling section.
Not only that, but impulse is force times time; if you multiply that out, you'll see that impulse is equal to momentum:
I = Ft
F = ma
a = v/t
F = mv/t
I = tmv/t = mv
P = mv
I = P
Thus, if we decrease the time of the collision, we must INCREASE THE FORCE. A more rigidly supported floor will attempt to stop the falling mass more quickly; thus, it is not the rigidity of the floor that determines its strength, and in fact higher rigidity multiplies the force, thus REDUCING the strength. It is the flexibility of the supports (and of the floor) that REDUCES the force, by distributing the momentum exchange over a greater period of time. However, this is ONLY true if the limits of elasticity of the supports are not exceeded; if they are, then THEY AND THAT WHICH THEY SUPPORT WILL GATHER MOMENTUM FROM THE FALLING MASS. Now, steel may be highly elastic, but it is not very flexible; that means that the floors were quite rigid. The mountings might have been flexible, but their limits of movement were extremely short. Thus, we see that the time over which the entire momentum of the falling mass would have applied force to the floor was very short, on the order of milliseconds (thousandths of a second; 0.001 seconds is a millisecond). And this means that the force would have been enormous, far beyond the elastic limits of the core columns. Which I have also said a number of times.
So to put it all together, if the first floor below the collapse couldn't stop the collapse, then no other floor could because of the increasing momentum of the collapsing section; and the first floor below the collapse was subjected to forces far beyond the abilities of its supports to handle. So what happened? The building collapsed.
Now, kinetic energy is NOT conserved; only total energy is. So when the falling mass slows, and loses kinetic energy, that's because some of the kinetic energy was turned to heat, either directly or during the performance of some work (like breaking the floor slab apart, bending the core columns, breaking the perimeter columns apart, etc.). The falling mass does not stop, it merely slows down. But when it does, then some of its kinetic energy must be dissipated. No matter how it is dissipated, it must all turn to heat as it does work.
A lot of work got done while the building was collapsing, and that means a lot of energy got dissipated as heat. Thus, a lot of heat was present in the rubble and the dust cloud after the building fell.
Schneibster
29th November 2005 - 09:41 PM
QUOTE (metamars+) I don't have the time to teach you physics. |
BWAHAHAHAHAHAHAHAHAHA! You don't have the PHYSICS to teach anyone physics!
yesitdid
29th November 2005 - 11:20 PM
| QUOTE | Now, kinetic energy is NOT conserved; only total energy is. So when the falling mass slows, and loses kinetic energy, that's because some of the kinetic energy was turned to heat, either directly or during the performance of some work (like breaking the floor slab apart, bending the core columns, breaking the perimeter columns apart, etc.). The falling mass does not stop, it merely slows down. But when it does, then some of its kinetic energy must be dissipated. No matter how it is dissipated, it must all turn to heat as it does work
<br>Well not all into heat. Some as you say goes into the deformation and breaking up of the structure and its contents, some into horizontal velocity component as pieces bounce off each other and of course into vibration that caused the loud noise and the seismic rumble each of which in turn convert into heat energy.
Schneibster
29th November 2005 - 11:23 PM
Arthur pointed out in a PM that I was unclear about where the energy to do the deforming and crushing and so forth came from. I think he's right, so I will clarify here. In addition, I'd like to give proper credit to yesitdid; my post is an expansion and explanation of the calculations from yesitdid's earlier post. The momentum, P, is found from: P = mv Where, m is mass and v is velocity. The kinetic energy, KE, however, is found from: KE = mv^2/2 Thus we see that the kinetic energy increases as half the square of the velocity, whereas the momentum only increases as the velocity. When momentum is transferred, it is conserved; however, KE is NOT conserved (although total energy is). The work of overcoming the resistance of the floor being struck is therefore not done by the momentum, but by the KE. Following yesitdid's lead, we'll use the real-world example: P = mv = (39 floors x 9.80665m/s^2 for 3m) To get velocity in terms of distance and acceleration, we'll use Eq. 9 from my post 35886 on this thread: v = a(√(2d/a)) = 9.80665m/s^2 x √(2 x 3m / 9.80665m/s^2) = 7.6707170460133647143265921338491 = 7.67m/s To get the mass of a floor, we'll use my calculation of 4285.5 metric tonnes per floor from that same post; thus, P(before) = mv = (4285.5t x 39) x 7.67m/s = 1282041458.1269207048466178129948 = 1,282,000,000 kg x m/s Now, the KE: KE(before) = mv^2/2 = ((4285.5t x 39) x (7.67m/s)^2)/2 = 4917088633.275 = 4.917GJ = 1,365,857.9536875 kWh OK, now with the added mass, we'll have 1,282,000,000 kg x m/s / (4285.5t x 40) = 7.4789491198630305964684273304982 = 7.47m/s As we can see, the velocity has dropped by about 1/40th. Now, the KE: KE(after) = ((4285.5t x 40) x ( 7.47m/s)^2)/2 = 4794161417.4431249999999999999938 = 4.794GJ for a loss of 122927215.83187500000000000000619 = 122.9MJ That 122.9MJ went into deforming, bending, crushing, and heating. It's equivalent to 0.0293803 US short tons of TNT, which is about 60 pounds of high explosive. Think you could collapse the core columns for one floor with 60 pounds of explosives? I bet you could do it with 6. Now THAT'S physics.
Schneibster
29th November 2005 - 11:29 PM
QUOTE (yesitdid+) Well not all into heat. |
Not all DIRECTLY into heat, but it all ends up heat anyway (although the sound energy doesn't wind up in the pile of rubble after it turns to heat, and some of the seismic energy doesn't either). But it all EVENTUALLY winds up as heat, and almost all of that heat is in the pile of rubble.
I think looking your post over that you got that; perhaps I wasn't clear enough I was talking about eventually.
Schneibster
29th November 2005 - 11:35 PM
Oh, and by the way, metamars, please note that no calculations involving some mythical "delay time" are needed; you can just figure it right on down, figuring the slowing at each step, to get the time needed for each step, and add them all up at the end. Or you could get tricky, since it involves a descending series, and do it all in one big calculation, if you know enough math. Heh.
Foxx
30th November 2005 - 02:47 AM
Floors, floors, floors ... pancaking floors... accelerating floors... impacting floors... decelerating floors... floors, floors, floors... free-falling floors... near free-falling floors... and every once in a blue moon, someone throws the dog a bone and says (under their breath, almost as a sideline issue) 'buckling columns' (as if these follow the same rules and forces as pancaking floors). All of the previous calculations only take into account collapsing floors (as if the towers were box-tubes full of floors [truss floors at that] and looked like this...  or this...  When are 'you people' going to take into account those 47 Massive Interior Core Columns and transverse stiffening beams ? ...  See any 'buckling' in this column? See any fracturing of the weld-joint? Do you see the size of the transverse stiffening beams which provided the lateral stiffness to the core columns? Do you think (or propose) that such connections will fail through 'buckling'... being pulled out of plumb by a couple of 1" bolts connecting the truss floors to the spandrels of the core columns? When you quit referring to floors and start referring to 'stories' (such as the 73 story,vs 72 story, etc, etc, etc...) AND... start to take into account the massive resistance and redundancy built into the central core columns laterally stiffened by huge transverse beams which provided ample resistance to buckling such as those beams and moment connections pictured above, THEN you will begin to display an understanding of the structural framework of the central core, and will realize that all of your calculations ONLY hold a shred a reality as long as you keep refusing to acknowledge the core which COULD NOT have collapsed according to your 'pancaking floors' calculations. Everyone is so wound up in theoretical calculations that only address 'collapsing pancaking floors' that you have lost touch with reality. As I read over the contortions, used to perform mathematical calculations on 'collapsing FLOORS, I am sitting here shaking my head in disbelief. 'Pilots', 'computer programmers', and 'cable guys' busying themselves with basic high school physics to address structural engineering aspects well beyond their understanding, and coming up with calculations and formulas that address only one structural aspect of the towers (as IF that aspect is the 'most important' structural aspect of the towers), and then extrapolating, that their basic physics calculations 'answer' how the towers fell). Heh... These calculations DO NOT address THE MOST IMPORTANT structural aspect, and therefore are barely relevant). Engineering professionals have various theories about how the 'damage' caused by the impact of the aircraft and the effects of the ensuing fire (the alleged inferno) combined to cause the 'Total Global Disproportionate Progressive Collapse' of the WTC towers. When evaluating the structure of the WTC towers, each 'expert' starts by making a set of assumptions. IF assumptions change, the analysis that is built on them often becomes invalid, so the accuracy of the initial assumptions about the WTC construction and parameters leading to 'collapse' is crucial. No one knows for a fact what damages were done to the core columns or to the fireproofing upon internal steel structures actually was. Of course, each 'engineer' (or engineering team) attempts to make its best guess... however each theory is still a 'guess', and as there is no consensus between ALL engineers and teams... to quote Weidlinger, Eagar, Bazant, Clifton. FEMA or NIST (as if 'one' speaks gospel) is erroneous and mere speculation. There are NO provable ' FACTS' in any of these guesses or speculations. Anyone basing their calculations on 'floor' failures, as if they can determine the speed, momentum or forces involved to lead to 'global collapse' (based soley on such simple calculations) is just pissing in the wind. IF the towers were simple box tubes with suspended truss floors spanning from side to side, these calculations might have some merit. As they were not... they tell us nothing of real importance. IF the towers were simple box tubes with suspended truss floors spanning from side to side, scenarios presented (such as simple falling-floors-scenarios) MAY have 'collapsed' as these proponents of gravity-driven collapse calculate. However, they were NOT, so these calculations mean very little. It is utterly impossible for a standard construction 'post and beam' (post & lintel) building...  ...to 'pancake' down through itself in a gravity driven collapse anywhere near the speed of free-fall, due to the resistance and multiple redundancies of alternate load bearing paths which must be compromised during failure... apart from controlled demolition The alleged 'buckling' af ALL columns symmetrically and instantaneously is impossible apart from the addition of some force like the Grinch (or unnatural cutting force) which removes the structural integrity of each story sequentially. The 'alleged' increasing momentum and force is only plausibly possible if the building was constructed of suspended floors falling on the next lower floor. This does not work (is NOT possible) in a standard 'post & lintel' construction, and the central core WAS structurally engineered as a post & beam construction, (just like traditional buildings). It could NOT (by any means) fail at the speed of 'suspended-floors' failing rates. Even IF, (in your fantasies) the WTC towers collapsed due to gravity driven causes, the suspended truss floors would strip away from the central core leaving a good portion of the central core standing. As we all know, this did not happen. In fact, there were parts of the much weaker perimeter core left standing while the central core (massive columns & transverse beams) were 'disintegrated' right down to the foundation. This is not possible in the real world of physics. Official government supporters... go sell your story to Popular Mechanics or Scientific American, or Guilianis biographer. I (for one) aren't in the market for bull-patties.
adoucette
30th November 2005 - 03:41 AM
QUOTE (Foxx+) Engineering professionals have various theories about how the 'damage' caused by the impact of the aircraft and the effects of the ensuing fire (the alleged inferno) combined to cause the 'Total Global Disproportionate Progressive Collapse' of the WTC towers.
When evaluating the structure of the WTC towers, each 'expert' starts by making a set of assumptions.
IF assumptions change, the analysis that is built on them often becomes invalid, so the accuracy of the initial assumptions about the WTC construction and parameters leading to 'collapse' is crucial.
No one knows for a fact what damages were done to the core columns or to the fireproofing upon internal steel structures actually was.
Of course, each 'engineer' (or engineering team) attempts to make its best guess... however each theory is still a 'guess', and as there is no consensus between ALL engineers and teams... to quote Weidlinger, Eagar, Bazant, Clifton. FEMA or NIST (as if 'one' speaks gospel) is erroneous and mere speculation.
There are NO provable 'FACTS' in any of these guesses or speculations. <br>I refer you to chapter 6 of the NIST document, on the modeling of the towers, the planes, the impact, the fires, the office space, the structural members, resistance of the fireproofing etc. This was no mere 'set of assumptions', the tower model was built off the plans and included subsequent modifications, the plane model came from Boeing and P&W design docs, the models were tested to verify they actually modeled the building. The simulation of just the crash took 2 weeks on a 12 node parallel computer system. So, no this was not a bunch of guys making guesses, it was a DETAILED analysis and computer simulation where the simulation results were verified against what was observed. So, is it a FACT? No, but it is as close to FACTUAL as has been done. What they did and how they did it is all laid out in detail. I've yet to see you punch any holes in their work. You keep handwaving that things are IMPOSSIBLE, but I've yet to see you prove any of these impossiblities. (reminds me of a line from Princess Bride about the meaning of Inconceivable) As to your pictures of beams, they actually make the case as there is no evidence of explosions yet they are twisted like pretzels. And while I agree with you, that any analysis that WE do will be simplistic in comparison to NIST's work, what CAN be shown is the Kinetic Energy of the falling building section, above the point of collapse, has sufficient energy to MASSIVELY overload those central columns. While I think Schneibster and YesItDid are on the right track, I also think that further analysis of the collapse will indicate that a great deal more Kinetic Energy was expended during the collapse than the last set of figures indicate and much of that went into demolishing the core columns, material within the floors and the floors themselves. Still, I'm positive we will find that there is a great excess of KE available, more than enough to do the job and with no help from any Controlled Demolition devices. Arthur
Schneibster
30th November 2005 - 03:49 AM
QUOTE (Faux+) When are 'you people' going to take into account those 47 Massive Interior Core Columns and transverse stiffening beams ? ... |
I did. You're lying again. QUOTE (Faux+) See any 'buckling' in this column? |
Faux, ONE section of ONE column? You're kidding, right? QUOTE (Faux+) See any fracturing of the weld-joint? |
Again, ONE weld joint? You're kidding, right? QUOTE (Faux+) Do you see the size of the transverse stiffening beams which provided the lateral stiffness to the core columns? Do you think (or propose) that such connections will fail through 'buckling'... being pulled out of plumb by a couple of 1" bolts connecting the truss floors to the spandrels of the core columns? |
Well, they look pretty buckled to me. Wonder what did that? Explosives, perhaps? No, no, that's right, explosives CUT the steel, they don't BEND it. QUOTE (Faux+) central core columns laterally stiffened by huge transverse beams which provided ample resistance to buckling such as those beams and moment connections pictured above |
Oh, you mean all those BUCKLED huge transverse beams? Are THOSE the huge transverse beams you're referring to? Where's all the "ample resistance" that kept them from BUCKLING, then? QUOTE (Faux+) you will begin to display an understanding of the structural framework of the central core |
Based on what I've written in this post alone, I'd have to say that my understanding of the structural framework of the central core considerably exceeds yours. Not to mention the fact that I'm LOOKING at your picture, and SEEING the buckled cross-braces, which are exactly what I would expect to see if everything happened just as I said. And that is MOST DEFINITELY NOT what I would expect to see if the building had been demolished with explosives; those core columns and lateral braces would have been CUT by the explosives. QUOTE (Faux+) 'Pilots', 'computer programmers', and 'cable guys' busying themselves with basic high school physics to address structural engineering aspects well beyond their understanding |
Well beyond YOUR understanding, perhaps. I think that's relatively obvious looking at the picture you posted and the "conclusions" you drew from it.
I don't see any point in any more of this. You've jumped from unfounded statements about a photo you apparently didn't actually consider the implications of, to more lies about what others have said, to ridiculous speculation. Again.
Faux, you are completely useless here. Why do you bother? No one's going to listen to your drivel for longer than it takes to look at the pictures you post, and see that what you say about them JUST AIN'T SO. If they even get past the lie in the VERY FIRST SENTENCE OF YOUR POST.
Foxx
30th November 2005 - 04:14 AM
Thanks for your reply Adoucette.
I think I will wait for others to make their remarks before responding in total to your reply.
However, one of your remarks stands out like a sore thumb to me...
| QUOTE | As to your pictures of beams, they actually make the case as there is no evidence of explosions yet they are twisted like pretzels.
<br>The 'twisting like pretzels' of the massive transverse beam (IMHO), was due to the 'fall', (and nothing to do with initiating events).
I agree with you that I see no signs of 'explosive actions' nor 'initial failure sequences' to cause this 'pretzel twisting'.
In my view, this 'twisting' occured during the 'fall' (or landing).
Far more important than this twisting of the transverse beam (from whatever cause)... is the condition of the core column.
Do you see any signs of 'buckling' or 'pre-collapse failures' in the column?
Do you see any fracturing at the weld joint?
Perhaps this picture is not as 'clear' as the WTC 7 photos we have been discussing?
Later
yesitdid
30th November 2005 - 04:33 AM
QUOTE (Foxx+Nov 30 2005, 02:47 AM) Everyone is so wound up in theoretical calculations that only address 'collapsing pancaking floors' that you have lost touch with reality. As I read over the contortions, used to perform mathematical calculations on 'collapsing FLOORS, I am sitting here shaking my head in disbelief. 'Pilots', 'computer programmers', and 'cable guys' busying themselves with basic high school physics to address structural engineering aspects well beyond their understanding, and coming up with calculations and formulas that address only one structural aspect of the towers (as IF that aspect is the 'most important' structural aspect of the towers), and then extrapolating, that their basic physics calculations 'answer' how the towers fell). Heh... These calculations DO NOT address THE MOST IMPORTANT structural aspect, and therefore are barely relevant). Heh, indeed, fiberglass specialist. do not attack anyone else's ability based on credentials Foxx. Your's ain't no better. As far as the simplified physics calcs of pancaking floors goes , hell, it was one of your guys who started it. by metamars in relation to Hoffman's claim. I understand why you shake your head at the calculations Foxx. You can't follow them. 
yesitdid
30th November 2005 - 04:36 AM
QUOTE (Foxx+Nov 30 2005, 04:14 AM)
Do you see any signs of 'buckling' or 'pre-collapse failures' in the column?
Do you see any fracturing at the weld joint?
Over an approx six to eight foot long section of ONE column?? You're kidding, right? 
Foxx
30th November 2005 - 04:41 AM
| QUOTE | Originally posted by Scheister
Based on what I've written in this post alone, I'd have to say that my understanding of the structural framework of the central core considerably exceeds yours.
<br>Would you? Hmmmmm ??? ....
QUOTE (-> | QUOTE | Originally posted by Scheister
Based on what I've written in this post alone, I'd have to say that my understanding of the structural framework of the central core considerably exceeds yours.
<br>Would you? Hmmmmm ??? ....
Originally posted by Scheister
Remember, this force is being transmitted down a rigid column of concrete with rigid columns of steel inside it; that means that it shatters rather than yielding.
<br>Reply by Foxx: ..."Tell me, Oh great wise one. If the steel columns were inside concrete columns, wouldn't that make them less susceptible to heat effects?...
---------
Yep, I guess you're right Scheister... you've really demonstrated your 'knowledge' of the structural aspects of the WTC towers.
Schneibster
30th November 2005 - 04:45 AM
Faux doesn't learn anything new, so it assumes no one else can either.
Foxx
30th November 2005 - 05:00 AM
QUOTE (Schneibster+Nov 30 2005, 04:45 AM) Faux doesn't learn anything new, so it assumes no one else can either. Oh, I think you are capable of learning, Schiester. You learned from me that the steel core columns were NOT encased in concrete... didn't you ??? If you listen well, (and pay attention)...you will learn more.
Schneibster
30th November 2005 - 05:08 AM
Stick around and you might learn some physics if you can get your head out of there.
metamars
30th November 2005 - 06:06 AM
| QUOTE | I never said an "incredibly" complex computer "simulation". Neither is the case.
To do this calculation by hand would take something like an hour (barring mathematical shortcuts), and it would be very boring, involving 73 iterations of basically the same process. To program on a computer would take something like half an hour, and at least be mildly entertaining.
<br>It's somewhat more complicated than I thought when I wrote this, due to the non-zero v0 term representing the downward velocity at the top of each floor, immediately after the impact. You end up having to solve a quadratic equation for t.
eq. 5.6.4 and 5.6.5 at http://www.library.cornell.edu/nr/bookcpdf/c5-6.pdf give you a computer friendly way to solve the quadratic. The physical (non-zero) value of t at each step should be given by x2, not x1, in 5.6.5
If nobody posts a solution by tomorrow, hopefully I will have the time to do it then.
adoucette
30th November 2005 - 07:04 AM
QUOTE (Foxx+Nov 30 2005, 04:14 AM) The 'twisting like pretzels' of the massive transverse beam (IMHO), was due to the 'fall', (and nothing to do with initiating events).
I agree with you that I see no signs of 'explosive actions' nor 'initial failure sequences' to cause this 'pretzel twisting'.
In my view, this 'twisting' occured during the 'fall' (or landing).
Far more important than this twisting of the transverse beam (from whatever cause)... is the condition of the core column.
Do you see any signs of 'buckling' or 'pre-collapse failures' in the column?
Do you see any fracturing at the weld joint?
Well if you look at the picture I think you would be hard pressed to come up with a way the impact of a fall would cause the twisting in opposite directions of the transverse beams. If the beam was in "free fall" as in a CD, the same problem applies. As to the Core Column, its a relatively short section, I think one would have to see the ENDS to make a determination of its condition. What I can assure you though, just from the picture, is the column doesn't extend very far off frame. Wonder why? Arthur
Foxx
30th November 2005 - 07:38 AM
| QUOTE | Originally posted by YID
Heh, indeed, fiberglass specialist.
do not attack anyone else's ability based on credentials Foxx. Your's ain't no better.
<br>Yid, I am no 'better' than anyone else posting here.
Scheister complains that I posted 'personal details' about him.(which I did not do, and had no clue until such was posted by someone else).
Yet you now mention that I am a composites technician. Isn't that posting 'personal details'?
(C'est la vie - Not that I care about it, really).
Thanks for you kudos regarding 'fiberglass specialist'.
http://foxxaero.homestead.com/indsail_001.html
(I am not Richard Jenkins - I just provided design input for the configuration of the Windjet water POC vehicle).
'Reinforced composites' is a highly advanced field which deals with materials engineering and structural design on a daily basis.
'Fiberglass boatbuilding' has advanced way beyond your wildest dreams...heh...
http://www.foxxaero.com/newsplash.html
Sure, it may not be hi-rise building architectural engineering, but it is a much more closely related field than (shall we say) 'electronics engineering'.
I design & build 'structures' every day.
Do you?
That doesn't make me any 'better' or 'more knowledgeable' than you (or anyone else)... we all have our own field of interests and expertise.
With regard to Scheister... so he is a computer programmer...so what?
I see no 'shame' in that.
Nor... in being a 'pilot' or a 'cable technician' or involved in any other 'trade'.
But, let's face the facts here.
Being a 'composites guy', a 'computer guy', a 'cable guy', a 'pilot guy', or a 'bricklayer guy' doesn't make any of us 'experts' on the WTC 'collapse' does it? Nor do these differing trades make us 'idiots'.
We are all now just speculating.
We have now all entered the nightmare (prophesized by Bill Manning - of Fire Engineering) that unless the destruction of real evidence is stopped (January 2002) , we will all be reduced to endless hypotheticizing about the real facts.
We are trying to debate the issues based upon speculation, postulation and 'logic'. (the last of which is sadly lacking in the posts of you official conspiracy theorists)
(as one Canadian to another)... Let's try to stick to the 'facts', shall we?
metamars
30th November 2005 - 01:03 PM
| QUOTE | As far as the simplified physics calcs of pancaking floors goes , hell, it was one of your guys who started it.
by metamars in relation to Hoffman's claim.
<br>Yes, indeed, and if the 15.5 second figure is correct, the fact that this calculation completely ignores any resistance due to the structural strength of the steel frame makes is all that much more damning to the official Fairy Tale.
As the calculation doesn't subtract out the weight of the steel frame, it does, in a way, take into account not just the lateral portion of the floors (which should be much easier to collapse via a pancaking process as compared to getting the columns to collapse in the sense of buckling or fracturing.)
BTW, I spoke to a cousin of mine last week who is an architect, and she informed me that the general principle when joining together pieces of a steel frame is to make the join only as strong (but no weaker) than the weaker of the 2 pieces being joined. That makes perfect sense ito efficiency.
I interpret this to mean that, a priori, the columns are no more likely to "fail" at their joins than anywhere else along their length. The periodicity of the floors does suggest a periodicity of failure points, if failure does occur, but where this failure should occur is unknown to me (though I'd guess just at the edge of the join). The fact that nobody seems to know anything about this strikes me as highly suspicious - anybody have any info? Foxx? One would think that NIST and FEMA would be GREATLY interested in the details of column failure, but their only interest in this boring (actually CRITICAL) subject seems limited to invoking it (in the case of NIST) to explain the collapse.
If this is correct, then that fact alone tells me that the NIST report is a cover-up - not worth the paper it's printed on, and a real insult to the families that lost loved ones.
Details, details! For them to be concerned with such boring details as yucky column failure modalities, I imagine they would have required at least $40 million and 6 years! W-h-h-h-h-h-y everybody knows that when columns fail, they REALLY fail! Since the game is over at that point, why should anybody CARE how the columns would actually fail??? Syrup with your pancakes, ladies and gentlemen?
Furthermore, this clearly suggests that the tree analogy I gave earlier in the thread is indeed somewhat appropriate. There's no good reason to create a join between a column and a lateral portion of a floor that is stronger than the weaker of the two, which is certainly the lateral portion of the floor. On a lower floor, this difference in strength is something like two orders of magnitude. By Floor 91, this is something like a factor of 20. (Yes, I realize that I am glossing over different kinds of strength.)
My poetic tree analogy, for anybody who missed it, is:
Take a sledge hammer and start hitting the branch of a tree, as hard as you please and in any direction you please. What will happen? I predict that the branch will break, and the tree remain standing.
Now take a ball and crane and start beating on the tree, proper. What will happen? Besides some branched getting broken, I predict that either the tree will break into 2 big pieces, or it will fall over. It will not break into 30 foot pieces.
In light of these considerations, I don't know about anybody else, but I find it ironic that the efficiency of WTC 1 & 2, which is often invoked to explain why the buildings failed (since making them strong enough to survive all kinds of trauma would have been prohibitively expensive) actually points to the impossibility of anything like a "column failure" theory . Thus, we are back to pancaking floors and huge columns, which at worst should fail by falling over and occasionally fracturing.
Alanis Morisette, anybody?
metamars
30th November 2005 - 01:28 PM
| QUOTE | In subsequent collisions the falling mass will increase while the individual floor mass remains the same. The initial velocity will no longer be zero and thus the velocity of subsequent collisions will be much greater than this one. therefore a 2.5% reduction in velocity is the single largest change due to these collisions and the further one goes the less significant the slowing gets.
<br>Indeed. If the velocity was decreased by 2.5% after each collision, e.g., the net effect would be a velocity decrease of 84%.
(1-2.5%)^^(73 floors) = 0.1575
Guest_yesitdid
30th November 2005 - 03:21 PM
No, your math is incorrect.
Besides the percentage change in subsequent floors is going to be less and less.
metamars
30th November 2005 - 03:35 PM
| QUOTE | No, your math is incorrect.
<br>The math as stated is correct, though the interpretation is off. Since there is acceleration (velocity is increasing), I think the effect of decreasing the velocity early in the collapse must have a disproportionately large effect after subsequent impacts. Thus, I expect an even bigger disparity between this sort of calculation - assuming 2.5% decrease in velocity after each impact - and what you would get in a free fall.
Maybe when I write my program, I will compute this also.
QUOTE (-> | QUOTE | No, your math is incorrect.
<br>The math as stated is correct, though the interpretation is off. Since there is acceleration (velocity is increasing), I think the effect of decreasing the velocity early in the collapse must have a disproportionately large effect after subsequent impacts. Thus, I expect an even bigger disparity between this sort of calculation - assuming 2.5% decrease in velocity after each impact - and what you would get in a free fall.
Maybe when I write my program, I will compute this also.
Besides the percentage change in subsequent floors is going to be less and less.
<br>Absolutely correct. Nobody is disputing that, and my calculation implies so much.
Of course, it's the net effect of 73 impacts that matter. Soon, all shall be revealed !!!
Schneibster
30th November 2005 - 05:06 PM
So gravity JUST STOPS WORKING, that right metamars? I like that one. I might put it in my .sig.
metamars
30th November 2005 - 05:15 PM
| QUOTE | So gravity JUST STOPS WORKING, that right metamars?
<br>Silly goose. If gravity stopped working, the building sections would just float (until blown about by wind) and never collapse at all. Don't you watch Star Trek?
Schneibster
30th November 2005 - 06:27 PM
Foxx, your point that we cannot know how large the forces were in the falling building is wrong. There's this thing you don't appear to know about; it's called a "conservation law." A conservation law is ALWAYS obeyed in an interaction (what you might call an "event"). After you figure all the details, no matter how complicated they are, it's GUARANTEED that the conservation laws will be obeyed. Please note that this is not necessarily common knowledge; so I am not attempting to belittle you or be insulting. I'm trying to tell you something you apparently don't know. There's no shame in that; it just IS. And I'm trying to help you fix it.
This is why we can use the conservation of energy, and the conservation of momentum, to figure out how much force there was, and how much energy there was, without recourse to complex computer models. Note that a good check of the computer models is to see whether what they describe OVERALL obeys these conservation laws; if it doesn't, then the model is wrong, period. Anybody who knows basic physics knows this.
Had the building suffered a PARTIAL collapse, we'd have a much larger problem; we'd need to know how big the columns got, and how thick the floors were, and a bunch of other stuff, in order to understand how it could have stopped collapsing; but because it JUST KEPT GOING, we have a relatively easy task. Stopping would require that it dissipate ALL the kinetic energy at the point during the fall where it stopped; but since it didn't, we know that it had AT LEAST MORE THAN ZERO kinetic energy right to the ground, and that means that (since it cannot ever have had zero mass) that it had AT LEAST MORE THAN ZERO momentum. And both energy and momentum are conserved.
This is a standard way of proceeding when doing calculations involving impact, and has been for several hundred years (since Newton figured it out). You can look it up in any basic physics textbook. The term to look for in the index is "impulse."
To put this another way, you don't have to know all the details, as long as you know it kept falling, and as long as you know that energy and momentum were conserved. If you don't find enough energy being released to KEEP it falling, then you've got a case for demolition. But when I see the energy equivalent to 60 pounds of high explosive being released on the VERY FIRST STORY (fine, we'll use story if you like) to collapse, and I know that it's moving its very slowest and has the very least kinetic energy difference before and after impact then, and that the amount of energy released can only get bigger and bigger after that, and I look at those columns (and please note that if the column was square, you're looking at something that came from low down in the building, they weren't hollow square columns high up on the building as we already know from multiple sources), I KNOW there's no way they had the strength to resist that. One pound of TNT would go through one of those columns with plenty to spare, I expect no more than a few ounces would be needed to sever one, and as you keep saying, there are only, what, forty-seven of them? There sure as hell aren't sixty. Hey, I've got thirteen pounds of TNT left over even if I use a whole pound for each one, so what's the problem? I haven't even MENTIONED the fact that whatever the heat might have been from the fires, the FIRST STORIES TO COLLAPSE would have had the maximum effect from it, whatever that effect might be (and no matter what it is, it's CERTAIN to have weakened them SOMEWHAT; we aren't talking about collapse INITIATION here, we're talking CONTINUATION of a collapse already in progress).
Don't invoke the perimeter columns, either, because we all know from the Vierendeel truss design paradigm that we know from multiple sources they fulfilled didn't involve them participating in holding up the floors; they were in fact held up by the core, via the hat truss. That's what it's FOR. There's no other reason to put a hat truss on top of the building but to help support the perimeter columns from the top, thus relieving stress on the moment arm connections between the perimeter columns and the spandrels and increasing the amount of stress from wind they could survive.
So we KNOW now that there is more than sufficient extra energy available to drive the collapse by gravity once it's started; the only remaining question is, how did it START? Because we KNOW that there's no need to use explosives to keep the collapse going once it's started; we can tell that from conservation of energy and conservation of momentum. Let us then assume that explosives were used to START the collapse.
From both videos, and from the photographic records and from other video records, we KNOW that BOTH BUILDINGS collapsed first on floors that had been the sites of extensive fires. Now, if we suppose that the explosives were ALREADY THERE, then we have to assume that not only they, but their detonating devices, were capable of surviving the heat of the fire. Detcord is obviously not an option; you can light it with a match. Electrical wiring isn't going to do it either; the insulation will melt right off it. Even teflon insulation isn't going to survive in a fire; give it a try with a cigarette lighter if you like. So what means of detonating these explosives (assuming that there are explosives capable of surviving a fire, which is also impossible, but an area I'll get into in a moment) was used? Radio? What kind of radio? Cell phones didn't work very well inside the towers, as we well know from references presented here; and cell phones use radio. So that's not going to work, is it?
Now, explosives are chemical compounds that contain a fuel and oxidizer, generally together in the same molecule; for example, trinitrotoluene (TNT) has toluene, a flammable, volatile solvent related to benzene, with three nitro- groups, the oxidizer. In general, you aren't going to get metal-like properties; you're going to have carbon and hydrogen as the fuel, and oxygen and nitrogen as the oxidizer, so you're going to get something relatively soft and with a pretty low melting point. In fact, there are no explosives that can survive a fire; TNT will BURN (interestingly, a fire is not sufficient to cause it to explode) like wood. RDX and HMX also have these properties, and HMX is sensitive to heat; plastic explosives are soft and therefore melt in a fire, even if they don't "cook off" because they contain HMX; nitroglycerine becomes incredibly unstable when exposed to heat; dynamite sweats nitroglycerine when heated; PETN is unstable and heat-sensitive like HMX. Right there, we've run through pretty much all the widely used explosives, with the exception of ANFO, and ammonium nitrate (the AN part) is also highly sensitive to heat (and shock, as well, which precludes it surviving the jet plane crash).
So we'll abandon explosives pre-set in the building to start the collapse, without even discussing how anyone could know what story to set them on. We are therefore left to assume (as our last option) that someone set explosives on those floors AFTER the planes crashed into them.
The problems with this are obvious; these floors were emitting smoke right up to the time of the collapse, indicating that there were active fires in them. No person could survive in that environment; without considering the heat or open flame, the smoke ALONE is sufficient to kill (most people who die in fires die from smoke inhalation), and a person in an oxygen mask doesn't exactly have the necessary freedom of vision to reliably place sensitive explosives in the correct places to ensure a collapse. Add in the heat and open flame, and you've got a situation that is completely unmanageable; it's beyond incredible to suppose that anyone could get such a sensitive and critical task done in that environment.
So now we've eliminated the use of explosives to CONTINUE the collapse (by showing that there was more than sufficient energy available to continue it once started), and we've eliminated the use of explosives to START the collapse (by eliminating all the ways they could have gotten onto the floors where the collapse started). What then were the explosives used for?
Foxx, I have addressed you reasonably and respectfully. I have furthermore ASSUMED that you are capable of separating your feelings from your judgement and making a dispassionate effort to understand what you're being told, and to judge on NON-EMOTIONAL GROUNDS whether it is plausible, which is a further considerable compliment. I have deliberately ASSUMED as well that you were merely NOT KNOWLEDGEABLE about physics, which is a situation easily remedied by giving you information, rather than stupid. I have avoided insult and inflammatory remarks.
If you are not capable of separating your judgement from your emotions, or not capable of dispassionately evaluating evidence, then there is no point in continuing the conversation; merely say so. There is no need to be insulting, and no need to be insulted; many people cannot do this.
If you don't understand why I'm saying what I'm saying, please ask, and I will answer respectfully and as completely as I can.
I will even apologize for by prior sarcastic and belittling remarks, and commit not to repeat them.
However, if you continue the sarcastic and belittling tone you have used in EVERY SINGLE POST YOU HAVE MADE ON THIS THREAD, then you may rest assured that I will dismiss you permanently as a person I wish to interact with, that I will not read another single word you write, and that I will not respond to any of it. The choice is up to you. By your response, everyone here will know whether you are credible or not.
adoucette
30th November 2005 - 06:40 PM
QUOTE (metamars+) I think the effect of decreasing the velocity early in the collapse must have a disproportionately large effect after subsequent impacts <br>Not really, think of it this way, the first floor is hit by the upper section falling at 9.85ms^2. The floor slows SLIGHTLY with the first impact but still retains most of its velocity, I don't think we really can know exactly what this velocity was with the data we have, so call this post impact velocity V1. What we do know is V1 > 0. Thus when the combined floors hit the second floor they are now dropping at the rate of V1 + 9.85ms^2. Thus the momentum has gone up (potentially quite a bit) yet the resistance of the next floor is essentially the same. Thus the decrease in velocity on the second impact should be LESS than the first. This same logic would persist all the way down unless the resistance of a floor increased SUBSTANTIALLY above the previous floors. Only if the resistance of a floor exceeds the KE of the falling mass will the collapse cease. But since the KE is increasing at a prodigious rate, its energy stays above the resistance of any set of floors or columns. Arthur
metamars
30th November 2005 - 06:47 PM
| QUOTE | I will even apologize for by prior sarcastic and belittling remarks, and commit not to repeat them.
<br>Thank-you. Hopefully Foxx will respond in kind. Remarks such as "son-of-an-idiot" have no place on a technical board.
I'm not exactly Mr. Diplomat myself in some of my postings, but at the end of the day, I attack ideas, and not people. The only exceptions that I can think of are politicians, lying journalists, and propagandistic talk show hosts.
yesitdid
30th November 2005 - 06:53 PM
QUOTE (metamars+Nov 30 2005, 01:28 PM) | QUOTE | In subsequent collisions the falling mass will increase while the individual floor mass remains the same. The initial velocity will no longer be zero and thus the velocity of subsequent collisions will be much greater than this one. therefore a 2.5% reduction in velocity is the single largest change due to these collisions and the further one goes the less significant the slowing gets.
<br>Indeed. If the velocity was decreased by 2.5% after each collision, e.g., the net effect would be a velocity decrease of 84%.
(1-2.5%)^^(73 floors) = 0.1575
If the total reduction of velocity is 84%:
In free fall the time to fall 73 floors at 4 meters per floor would be 7.7 seconds and the final velocity would be 75m/s(270Km/hr)
16% of this is 12m/s(43Km/hr = 26.7 mi/hr)
Does that even sound correct or does it sound rediculously slow?
I did the calcs down to a 4 floor fall and at that point I have it moving at just under 15m/s and it gets faster with each floor so getting down to 12m/s does seem odd.
yesitdid
30th November 2005 - 07:05 PM
QUOTE (Foxx+Nov 30 2005, 07:38 AM) | QUOTE | Originally posted by YID
Heh, indeed, fiberglass specialist.
do not attack anyone else's ability based on credentials Foxx. Your's ain't no better.
<br>Yid, I am no 'better' than anyone else posting here.
Scheister complains that I posted 'personal details' about him.(which I did not do, and had no clue until such was posted by someone else).
Yet you now mention that I am a composites technician. Isn't that posting 'personal details'?
(C'est la vie - Not that I care about it, really).
Thanks for you kudos regarding 'fiberglass specialist'.
http://foxxaero.homestead.com/indsail_001.html
(I am not Richard Jenkins - I just provided design input for the configuration of the Windjet water POC vehicle).
'Reinforced composites' is a highly advanced field which deals with materials engineering and structural design on a daily basis.
'Fiberglass boatbuilding' has advanced way beyond your wildest dreams...heh...
http://www.foxxaero.com/newsplash.html
Sure, it may not be hi-rise building architectural engineering, but it is a much more closely related field than (shall we say) 'electronics engineering'.
I design & build 'structures' every day.
Do you?
That doesn't make me any 'better' or 'more knowledgeable' than you (or anyone else)... we all have our own field of interests and expertise.
With regard to Scheister... so he is a computer programmer...so what?
I see no 'shame' in that.
Nor... in being a 'pilot' or a 'cable technician' or involved in any other 'trade'.
But, let's face the facts here.
Being a 'composites guy', a 'computer guy', a 'cable guy', a 'pilot guy', or a 'bricklayer guy' doesn't make any of us 'experts' on the WTC 'collapse' does it? Nor do these differing trades make us 'idiots'.
We are all now just speculating.
We have now all entered the nightmare (prophesized by Bill Manning - of Fire Engineering) that unless the destruction of real evidence is stopped (January 2002) , we will all be reduced to endless hypotheticizing about the real facts.
We are trying to debate the issues based upon speculation, postulation and 'logic'. (the last of which is sadly lacking in the posts of you official conspiracy theorists)
(as one Canadian to another)... Let's try to stick to the 'facts', shall we? Ok just a minor oversight on your part then. You could as easily have stated
"'Pilots', 'computer programmers', 'cable guys' and 'composites manufacturers' busying themselves ..." on various aspects of the 9/11 events. 
yesitdid
30th November 2005 - 07:07 PM
[b]Further to: (quadratic equations ain't no thang)
| QUOTE | Mass of 39 floors = 39m
velocity v=v(initial) + at
First drop, assuming free fall, the momentum of the top section will be
p(1) = 39m(at) ,, (initial velocity is zero)
Now the next floor collides inelastically with the 39 floor upper section and that will reduce the velocity(conservation of momentum)
p(1)=p(2)=40mv
where v is the velocity once the top 39 floors combines with the next floor
so
39m(at)=40mv
(39/40)(at)=v
at is the velocity in free fall of the upper section travelling 4 meters
4=0.5 at^2 = 0.5(9.8)t^2
t=0.904 seconds so at=9.8(0.904) = 8.85 m/s
(39/40)(8.85)=8.63 m/s
So in the first collision as envisioned by this simplified accounting changes the velocity by
(8.85-8.63)/8.85 *100= 2.5%
In subsequent collisions the falling mass will increase while the individual floor mass remains the same. The initial velocity will no longer be zero and thus the velocity of subsequent collisions will be much greater than this one. therefore a 2.5% reduction in velocity is the single largest change due to these collisions and the further one goes the less significant the slowing gets.
<br>To find the velocity as this, now 40 floor mass, inelastically hits the next floor down we have
4 = 0.5(9.8)t^2 + 8.63t + 0
in which which the distance is 4 meters, the acceleration is 9.8m/s^2 and the initial velocity is 8.63m/s. We need the time of fall first and the above is a quadratic equation, rewritten it is
0 = 4.9t^2 + 8.63t - 4
so the solution to this is
t= (-8.63+/-sqrt(8.63^2 -4(4.9)(-4))/2(4.9)
t=0.38 seconds (or -2.14 seconds which is obviously not a possible solution in the physical sense)
So the time it takes to fall to the next floor is 0.38 seconds
total time of fall is 1.284 seconds, it has fallen 8 meters. In free fall the time would have been
t=sqrt(16/9.8)=1.278 seconds so the time is 2.0% longer than free fall
the velocity is then 8.63 + 9.8(0.38)^2 = 10.0m/s
and now it's velocity is reduced when it takes on the mass of the next floor
as 40(10.0)=41v
v=(40/41)10.0 = 9.76m/s (or a 2.4% reduction in velocity)
To the next floor
the solution to the quadratic is now
t = {-9.76+/-sqrt(9.76^2 - 4(4.9)(-4)}/2(4.9)
t= 0.35
thus the velocity is 9.76 + 9.8(0.35) = 13.18m/s
The mass has now fallen three floors, a total of 12 meters and taken 1.64 seconds to do so.
In free fall it would have taken
t=sqrt(24/9.8) = 1.57 seconds
The time difference is (1.63-1.57)/1.57 X 100 = 4.1% slower than free fall.
Next floor:
The 41m mass is moving at 13.18m/s when it gains another floor mass m
41m(13.18)=42m(v)
(41/42)13.18=v=12.87m/s a reduction of (13.18-12.87)/13.18 X 100 = 2.4%
the solution to the quadratic is now
t=(-12.87+/-sqrt(12.87^2 - 4(4.9)(-4))/2(4.9)
t=0.28 seconds
v=12.18 + 9.8(0.28) = 14.92m/s
total time of fall now 1.91 seconds which in free fall would have been(for 16m)
t-sqrt(32/9.8)=1.81sec
The time of fall is now 5.7% slower than free fall
adoucette
30th November 2005 - 07:36 PM
QUOTE (metamars+Nov 30 2005, 06:47 PM) | QUOTE | I will even apologize for by prior sarcastic and belittling remarks, and commit not to repeat them.
<br>Thank-you. Hopefully Foxx will respond in kind. Remarks such as "son-of-an-idiot" have no place on a technical board.
I'm not exactly Mr. Diplomat myself in some of my postings, but at the end of the day, I attack ideas, and not people. The only exceptions that I can think of are politicians, lying journalists, and propagandistic talk show hosts.
Why Metamars, you ignorant Slut.....
Arthur
ps just kidding, hope you watch SNL.
metamars
30th November 2005 - 08:04 PM
| QUOTE | The time of fall is now 5.7% slower than free fall
<br>You forgot the punch line. After 3 floors, by my estimate the velocity would be (.875)^^3 of the free fall time, which is about 67%.
Obviously, if you're right (I didn't carefully check, but I assume so), my estimate is more than a little off. 
Nevertheless, the computer program I'm going to write will not depend on hopelessly wrong estimates. The real question is, after 73 floors will it turn out to be approximately 50% of the expected free fall speed, or not?
Schneibster
30th November 2005 - 08:43 PM
QUOTE (metamars+Nov 30 2005, 05:15 PM) | QUOTE | So gravity JUST STOPS WORKING, that right metamars?
<br>Silly goose. If gravity stopped working, the building sections would just float (until blown about by wind) and never collapse at all. Don't you watch Star Trek?
Metamars, adding the percentages together assumes that they are percentages of the same quantity; but this ignores that under the influence of gravity, the percentage becomes smaller and smaller while the amount becomes larger and larger.
This is an obvious example of you not understanding how math works; I don't mean that to be insulting, it is an observation of a fact. I'd like the opportunity to show you how this is wrong, but if every time I tell you something is wrong, you take it as an insult, then I see no point in it. I'll just point out it's wrong, and if you've said something nasty to me, I'll insult you back; if you'll review this thread, you'll find that's precisely what has happened.
The tone of this post is sufficiently self-deprecating that I find no insult in it, and therefore I respond without being insulting (unless you interpret the fact that I've pointed out a clear flaw in your math incorrectly as an insult) since I have not been insulted. You might try addressing me in this manner on a more frequent basis, if you wish to carry on a dialog.
Edited to add: having read your recent post in response to my post to Foxx, I'd like to point out that the apology was to him, and offer you one as well, rather than having you dependent upon my communications with someone else. Based on your response in that post, I'll assume you'll find this acceptable.
metamars
30th November 2005 - 09:17 PM
| QUOTE | This is an obvious example of you not understanding how math works; I don't mean that to be insulting, it is an observation of a fact.
<br>Well, this sure beats being called a liar!
Shneibster, you're becoming almost lovable!!!
I have already admitted my estimate was hopelessly wrong. I do not consider myself a pope, that's for sure. Unlike you, though, I do not conclude from this that I "do not understand how math works". That's a rather broad statement, don't you think? I have noted your curious statements regarding conservation of energy in Hoffman's paper, which also are hopelessly wrong, and furthermore, I showed this in detail. I have not concluded, though, that you "don't understand how physics works"
FWIW, I have taken courses in advanced calculus, and had to prove convergence/divergence of many a series. That was a long time ago.....
I will almost surely get an accurate value before tomorrow, and post my source code, besides. If it's the result I expect (15.5 seconds), then this will provide a powerful wakeup call for not only physicists, but engineers, also. I presume that Ph.D. physicists and engineers at accredited universities do "understand how math works", and I'm sure you believe this, also.
I did a Google search at wtc7.net for '5.5' and 'linear momentum'. Unfortunately, no hits that gave this calculation, already worked out or even suggested.
metamars
30th November 2005 - 09:47 PM
| QUOTE | I did a Google search at wtc7.net for '5.5' and 'linear momentum'. Unfortunately, no hits that gave this calculation, already worked out or even suggested.
<br>Yet another blunder. I searched on 15.5, not 5.5.
Schneibster
30th November 2005 - 09:56 PM
Well, since you push the issue: QUOTE (metamars+) If the velocity was decreased by 2.5% after each collision, e.g., the net effect would be a velocity decrease of 84%.
(1-2.5%)^^(73 floors) = 0.1575 <br> QUOTE (metamars+) The math as stated is correct, though the interpretation is off. <br> QUOTE (metamars+) I do not conclude from this that I "do not understand how math works". <br>You have added percentages of a fluctuating value together without taking the fluctations into account; it has been definitively proven that the percentage must decrease from one impact to the next, and the total value of the momentum must increase from one impact to the next. The grounds on which this is asserted are: 1. Conservation of momentum, a well-known and long-proven axiom of real-world physics. 2. The similarly well-know and long proven axioms of the existence and magnitude of the force of gravity. 3. The fact that matter has weight, which is a downward force imposed upon it by gravity. So, which of these do you deny? And if you deny none of them (and I don't see how you can), then what part of the demonstration using them do you deny? I don't see a criticism of it. Therefore, I conclude that you don't know about the mathematics and can't see why it's wrong to take a descending percentage of an increasing value, and add only the first given percentage together to get a total percentage. The math as stated is incorrect, since it does not model the real-world occurences by any stretch of the imagination.
yesitdid
30th November 2005 - 11:43 PM
I would like to point out that the ONLY way to get an actual free fall time(disregarding any air resistance which would in fact be negligible) is to blow all the columns on all floors at the same time. This was quite obviously not the case.
the next fastest would be to time the blowing of the columns to coincide with the falling mass reaching the level of each explosive layer. This would be the closest to the simple inelastic exercise we are doing. This would differ significantly though in the non-inelastic nature of each collision.
Schneibster
1st December 2005 - 12:57 AM
I have begun coding a simulation of the collapse of 2 WTC. I have realized that something incredibly important has been left out; the distance to fall is not 418m, but 71/110 of 418m, or 269.8m.
By
t = √(2d/a) = √((2 x 269.8m)/9.80665m/s^2)
= 7.417808763529092758427200860118s
This is free-fall time from 269.8m.
By
v = a(√(2d/a)) = 9.80665m/s^2 x √((2 x 269.8m)/9.80665m/s^2)
= 72.743854310862577499430109314876m/s
I am using these figures to QA my program and find missing steps. I hope to have something tomorrow. I will let y'all know when I do; it will be perl, so that anyone can download and install perl and run the program to verify it for themselves.
I should tell you that the algorithm we (yesitdid and I) have been using to calculate the step-by-step results is currently yielding garbage, so it is apparently incorrect. It is intuitively obvious to the most casual observer that if the velocity is being reduced at each step, then the total time must be greater than the free fall time; however, that algorithm is currently yielding times around 3 seconds, and an impact velocity of over 400m/s (which is obviously also impossible). When I am done, y'all can code review it (assuming there is another perl programmer here).
Really, I should have done this long ago; it's an easy way to check what happened, and you don't need a huge computer to run it. It will give us a way to look at the FEMA report and decide if they're even in the ball park. Note as well that the time of seven and a half seconds for free fall from the collapse gives considerably more leeway for things to occur in the 12-15 seconds observed collapse time, so I am reasonably confident that when all is said and done, we will be able to tell whether the collapse could possibly have been gravity-driven, or if demolition is the only possible answer.
RealityCheck
1st December 2005 - 01:14 AM
Hi all.
Just dropped in to see what was happenin'. What a pleasant surprise! Actual debate and information/view exchange instead of 'slanging'. What's the world coming to?
Anyhow, I've got another 'common-sense' observation: If, as I read, the 'HAT TRUSS' was 'tensioning' the EXTERNAL columns (because they were half-hanging, as it were, off the hat truss) then as soon as the hat truss support ended, the previously-TENSIONED outer colums would be 'rebounding' DOWNWARDS and PULLING on the FLOOR TRUSSES and CORE COLUMNS. Thus ELASTIC RECOVERY down the full length of the remaining outer-columns-steel would be AN EXTRA source of INITIAL 'collapse 'acceleration' THAT IS NOT PURELY GRAVITATIONAL in character, but SPRUNG TENSION in character. And like massively-tensioned gigantic rubber cords, these outer columns would NOT be limited to FREE FALL energy-expenditure rates, but steel-tension--recovery rates that far exceed the rate of gravity's action AT THE BEGINNING OF THE GLOBAL COLLAPSE. Also, such suddenly-released SHEAR forces downwards would have had some effect on any 'fittings'joints along their length; so perhaps this PRIOR stress 'compromised' such connections to the point that they were NOT in OPTIMUM POSITION or CONDITION to FULLY RESIST whatever came AFTER as a result of gravity/impulse stresses etc.
Another observation comes to mind just now: If the outer walls had been 'weaker' (ie, just 'facade' rather than for such structural purpose), then any collapse debris would NOT have been 'contained' within the outer perimeter walls FROM ALMOST THE FIRST FEW MOMENTS TO THE LAST. Meaning that most of the debris would have 'shed' OUTWARD more easily and so not overloaded the core/interior so much and so CONSISTENTLY DOWN as opposed to OUTWARD. In which case, the towers may have been 'branch-shredded' for some stories, but this 'shredding' would have 'petered out' because there woul NOT have been the 'weight buildup' as happened in the 'contained' debris accumulation scenario.
Oh well, I'll just go back to my usual haunts and leave all you 'now nice' guys to it. Ciao.
RealityCheck.
.
metamars
1st December 2005 - 01:47 AM
| QUOTE | The math as stated is incorrect,
<br>What do you get when you calculate (1-2.5%)^^(73 floors) ?
I used MS Windows calculator to calculate this. What do you get, using whatever calculator you happen to use? (Please tell us which one it its.)
metamars
1st December 2005 - 02:35 AM
| QUOTE | I have begun coding a simulation of the collapse of 2 WTC. I have realized that something incredibly important has been left out; the distance to fall is not 418m, but 71/110 of 418m, or 269.8m.
<br>Hmmmmm.
So, does this mean that you "do not understand how math works"? Or, perhaps, that you "do not understand how physics works"?
I am making no such claim, nor do I believe this and for some reason wish to keep it to myself, but I am wondering if you will now make such a claim?
zoktoberfest
1st December 2005 - 02:46 AM
Quote; schneibster
Let us then assume that explosives were used to START the collapse. From both videos, and from the photographic records and from other video records, we KNOW that BOTH BUILDINGS collapsed first on floors that had been the sites of extensive fires. Now, if we suppose that the explosives were ALREADY THERE, then we have to assume that not only they, but their detonating devices, were capable of surviving the heat of the fire. So what means of detonating these explosives (assuming that there are explosives capable of surviving a fire, which is also impossible, but an area I'll get into in a moment) was used? Radio? What kind of radio? Cell phones didn't work very well inside the towers, as we well know from references presented here; and cell phones use radio. So that's not going to work, is it? So we'll abandon explosives pre-set in the building to start the collapse, without even discussing how anyone could know what story to set them on. We are therefore left to assume (as our last option) that someone set explosives on those floors AFTER the planes crashed into them.
Everyone noticed the unusual flash emanating from the nose of the planes at pre-impact. Right? Regardless of what you thought it was, it registered on the videos. What aviation system on a normal 757 could produce that effect and for what possible aeronautical purpose? If the planes weren't normal, then maybe the flash was a calibration mechanism that alerted an optical sensor watching the buildings as to the exact point of impact (meters above a reference point). Knowing that, a precisely timed and accelerated explosive device could have been sent up the appropriate elevator shaft, just prior to desired demolition time. - It could have been mounted to the top of an elevator. They have phones on board and therefore, could have received programming that way. If I'm not mistaken, elevators have independent power and communications systems to be less vulnerable during emergencies.- Blowing a nice section out of the center shaft, at or just below the impact site, would have helped things along nicely, wouldn't you say. It also would make the collapse sequence look natural because after all, it was fire and impact damage that brought down these buildings into there own foot prints. Right?
metamars
1st December 2005 - 05:19 AM
Initial results of computer calculation of changes in free fall time due to conservation of momentum
Tbe net net is only a minor increase in time of fall, compared to free fall. I think I see why Hoffman doesn't have this on his web site!
Following is my results, then source code (Visual Basic 6.0). I haven't had time to double check (except for computing for a collapse starting at floor 91), but it certainly looks right, even if it doesn't support the notion of a demolition.
If someone has VB, feel free to plug in the relevant numbers for WTC 7 and post. Otherwise, I will try to do this tomorrow.
Results
========================
The total elapsed time is 8.94236151144391
fdx is the "floor index". Floor 73 has index = 1, Floor 72 has index = 2, etc.
v0 is (in general) the time just after collision (in the special case of fdx = 1, v0 = 0)
vb is the time just before a collision
t is the time interval to drop by a height h, the height of one floor
=======================
fdx t v0 vb
1 .876 0.0 8.5846
2 .3695 8.3645 11.9859
3 .2872 11.6862 14.5005
4 .245 14.1468 16.5478
5 .2183 16.1538 18.2932
6 .1995 17.8677 19.823
7 .1854 19.3725 21.1894
8 .1743 20.7185 22.4266
9 .1653 21.9391 23.5588
10 .1578 23.0576 24.6038
11 .1514 24.0912 25.5751
12 .1459 25.0531 26.4831
13 .1411 25.9534 27.3364
14 .1369 26.8004 28.1417
15 .1331 27.6005 28.9048
16 .1297 28.3594 29.6302
17 .1266 29.0815 30.3221
18 .1238 29.7708 30.9838
19 .1212 30.4305 31.6182
20 .1188 31.0635 32.2279
21 .1166 31.6723 32.8151
22 .1146 32.2589 33.3816
23 .1127 32.8252 33.9292
24 .1109 33.373 34.4595
25 .1092 33.9037 34.9736
26 .1076 34.4185 35.4729
27 .1061 34.9187 35.9584
28 .1047 35.4052 36.4311
29 .1033 35.8791 36.8918
30 .1021 36.3412 37.3414
31 .1008 36.7923 37.7805
32 .0997 37.233 38.2098
33 .0986 37.6639 38.6299
34 .0975 38.0858 39.0413
35 .0965 38.4991 39.4446
36 .0955 38.9043 39.8401
37 .0946 39.3018 40.2284
38 .0936 39.692 40.6098
39 .0928 40.0754 40.9846
40 .0919 40.4523 41.3532
41 .0911 40.823 41.7159
42 .0903 41.1878 42.0729
43 .0896 41.547 42.4247
44 .0888 41.9009 42.7713
45 .0881 42.2497 43.113
46 .0874 42.5936 43.4501
47 .0867 42.9328 43.7827
48 .0861 43.2676 44.111
49 .0854 43.5981 44.4352
50 .0848 43.9244 44.7555
51 .0842 44.2469 45.072
52 .0836 44.5656 45.3849
53 .083 44.8806 45.6942
54 .0825 45.1921 46.0002
55 .0819 45.5002 46.303
56 .0814 45.8051 46.6026
57 .0809 46.1068 46.8992
58 .0803 46.4055 47.1929
59 .0798 46.7013 47.4838
60 .0794 46.9943 47.7719
61 .0789 47.2844 48.0574
62 .0784 47.572 48.3404
63 .0779 47.8569 48.6208
64 .0775 48.1394 48.8989
65 .0771 48.4195 49.1746
66 .0766 48.6972 49.4481
67 .0762 48.9726 49.7193
68 .0758 49.2458 49.9885
69 .0754 49.5169 50.2555
70 .075 49.7858 50.5205
71 .0746 50.0528 50.7836
72 .0742 50.3177 51.0448
73 .0738 50.5807 51.304
. 8.5846
2 .3695 8.3645 11.9859
3 .2872 11.6862 14.5005
4 .245 14.1468 16.5478
5 .2183 16.1538 18.2932
6 .1995 17.8677 19.823
7 .1854 19.3725 21.1894
8 .1743 20.7185 22.4266
9 .1653 21.9391 23.5588
10 .1578 23.0576 24.6038
11 .1514 24.0912 25.5751
12 .1459 25.0531 26.4831
13 .1411 25.9534 27.3364
14 .1369 26.8004 28.1417
15 .1331 27.6005 28.9048
16 .1297 28.3594 29.6302
17 .1266 29.0815 30.3221
18 .1238 29.7708 30.9838
19 .1212 30.4305 31.6182
20 .1188 31.0635 32.2279
21 .1166 31.6723 32.8151
22 .1146 32.2589 33.3816
23 .1127 32.8252 33.9292
24 .1109 33.373 34.4595
25 .1092 33.9037 34.9736
26 .1076 34.4185 35.4729
27 .1061 34.9187 35.9584
28 .1047 35.4052 36.4311
29 .1033 35.8791 36.8918
30 .1021 36.3412 37.3414
31 .1008 36.7923 37.7805
32 .0997 37.233 38.2098
33 .0986 37.6639 38.6299
34 .0975 38.0858 39.0413
35 .0965 38.4991 39.4446
36 .0955 38.9043 39.8401
37 .0946 39.3018 40.2284
38 .0936 39.692 40.6098
39 .0928 40.0754 40.9846
40 .0919 40.4523 41.3532
41 .0911 40.823 41.7159
42 .0903 41.1878 42.0729
43 .0896 41.547 42.4247
44 .0888 41.9009 42.7713
45 .0881 42.2497 43.113
46 .0874 42.5936 43.4501
47 .0867 42.9328 43.7827
48 .0861 43.2676 44.111
49 .0854 43.5981 44.4352
50 .0848 43.9244 44.7555
51 .0842 44.2469 45.072
52 .0836 44.5656 45.3849
53 .083 44.8806 45.6942
54 .0825 45.1921 46.0002
55 .0819 45.5002 46.303
56 .0814 45.8051 46.6026
57 .0809 46.1068 46.8992
58 .0803 46.4055 47.1929
59 .0798 46.7013 47.4838
60 .0794 46.9943 47.7719
61 .0789 47.2844 48.0574
62 .0784 47.572 48.3404
63 .0779 47.8569 48.6208
64 .0775 48.1394 48.8989
65 .0771 48.4195 49.1746
66 .0766 48.6972 49.4481
67 .0762 48.9726 49.7193
68 .0758 49.2458 49.9885
69 .0754 49.5169 50.2555
70 .075 49.7858 50.5205
71 .0746 50.0528 50.7836
72 .0742 50.3177 51.0448
73 .0738 50.5807 51.304
Source Code
===========================
Private Const g = 9.8
Private Const h = 3.76
Private Const m1Floor = 4054054.05 'not actually used, since g is considered a constant '4.5 x 10 ^8 / 111 kg
Private fdx As Integer
Private vb() As Double
Private v0() As Double
Private t() As Double
Private Sub GetTotalElapsedTime()
ReDim vb(1 To 73)
ReDim v0(1 To 73)
ReDim t(1 To 73)
v0(1) = 0 'since starting from rest
For fdx = 1 To 73
'get the time it takes to drop by h
t(fdx) = GetTimeInterval(fdx)
'get the velocity just before impact
vb(fdx) = Get_vb(fdx)
'get the velocity after impact, which is v0 for the next floor
If fdx < 73 Then
v0(fdx + 1) = Get_v0(fdx)
End If
Next
'Sum up the time intervals
Dim sum As Double
For fdx = 1 To 73
sum = sum + t(fdx)
Next
Debug.Print "The total elapsed time is " & sum
Debug.Print "======================="
Debug.Print "fdx t v0 vb"
For fdx = 1 To 73
Debug.Print fdx & " " & Format$(t(fdx), "##.####") & " " & Format$(v0(fdx), "##.####") & " " & Format$(vb(fdx), "##.####")
Next
End Sub
Public Function Get_v0(fdx) As Double
'use conservation of momentum to get velocity after impact
'this actually returns v0 of floor fdx + 1
Dim v0 As Double
'momentum before impact is (37 + fdx) * m1Floor * vb(fdx)
'momentum after impact is (37 + fdx + 1) * m1Floor * v0
'by conservation of momentum, these are equal; thus:
v0 = ((37 + fdx) * vb(fdx)) / (37 + fdx + 1) 'm1Floor cancels out
Get_v0 = v0
End Function
Public Function GetTimeInterval(fdx As Integer) As Double
'this is the time interval it takes to drop a distance h
'above the floor with index = fdx to the floor, itself
'the eqn of motion is: (1/2)gt^^2 + v0t -h = 0
Dim x0, x1 As Double
Dim q, a, b, c As Double
a = g / 2
b = v0(fdx)
c = -h
'where a,b,c defined by: at^^2 + bt + c = 0
q = -0.5 * (b + Sqr(b * b - 4 * a * c))
x0 = q / a
x1 = c / q
Debug.Print "x0 = " & x0
Debug.Print "x1 = " & x1
If (x0 < 0 And x1 < 0) Or (x0 > 0 And x1 > 0) Then
Debug.Assert False
End If
If x0 > 0 Then
GetTimeInterval = x0
Else
GetTimeInterval = x1
End If
End Function
Public Function Get_vb(fdx) As Double
'this is the velocity instantaneously before impact of floor with
'index = fdx
Dim vb As Double
vb = g * t(fdx) + v0(fdx)
Get_vb = vb
End Function
Private Sub Command1_Click()
GetTotalElapsedTime
End Sub
metamars
1st December 2005 - 05:56 AM
| QUOTE | even if it doesn't support the notion of a demolition.
<br>Actually, in light of Foxx's recent post, it would be more accurate to say that this calculation doesn't support the naive idea of demolition of buildings, wherein each colum is simultaneously cut on each floor sequentially, timed just right such that that there is essentially no structural resistance in the collapse zone.
I wonder: what is considered an optimal collapse methodology wrt speed in a CD? I could see why professional practitioners of CD might not want free fall speed in an area with adjacent buildings. All that rubble hitting the ground at once at high speed might constitute a mini-earthquake. But, why do they not slow it down such that demolition takes, say, 1 minute, and kicks up that much less dust?
In fact, such considerations make me wonder: was the reason that so much of the building was turned to dust perhaps have nothing to do with being easier to clean up, but everything to do with preventing a "mini-earthquake"? 'Considerate neighbor murderers', perhaps?
Foxx
1st December 2005 - 06:06 AM
| QUOTE | Originally posted by Schneibster
Foxx, your point that we cannot know how large the forces were in the falling building is wrong.
<br>Ehhh???
It is possible that I mispoke, but I do not recall stating anything to the effect that "we cannot know how large the forces were in the building". I think you may have misinterpreted my meaning from another statement? Kindly provide the quote you are referring to.
QUOTE (-> | QUOTE | Originally posted by Schneibster
Foxx, your point that we cannot know how large the forces were in the falling building is wrong.
<br>Ehhh???
It is possible that I mispoke, but I do not recall stating anything to the effect that "we cannot know how large the forces were in the building". I think you may have misinterpreted my meaning from another statement? Kindly provide the quote you are referring to.
by Schneibster
Had the building suffered a PARTIAL collapse, we'd have a much larger problem; we'd need to know how big the columns got, and how thick the floors were, and a bunch of other stuff, in order to understand how it could have stopped collapsing; but because it JUST KEPT GOING, we have a relatively easy task.
<br>You may be correct, but if the buildings had only suffered a partial collapse (as in the case of every other historical steel-framed building collapse caused by structural damage related to fire, then there would be no anomaly that needed addressing, so we wouldn't be concerned about analyzing the forces or resistance to understand what exactly caused the collapse to cease. Again you seem to repeat the mantra that once 'collapse' is initiated, nothing is going to stop it... (it's 'inevitable ! )
This unfounded mantra flies in the face of every other fire-induced steel-framed building 'collapse' in history which WERE only Partial Collapses. There is no need to study all of those to see WHAT caused the cessation of the collapse.
One example of Partial Collapse (although not caused by fire but rather by 'Amazing Flying Columns' ) occured at Bankers Trust...
A section of perimeter column trees estimated to weigh over 90 tons travelling at free-fall speeds impacted the face of Bankers Trust... but a few (much smaller beams than were in the WTC towers) stopped this massive dynamic impact without 'progressively collapsing' the lower section of building right to the ground.
http://oceanmirage.homestead.com/AFC01_002.html
| QUOTE | by Schneibster
Stopping would require that it dissipate ALL the kinetic energy at the point during the fall where it stopped; but since it didn't, we know that it had AT LEAST MORE THAN ZERO kinetic energy right to the ground, and that means that (since it cannot ever have had zero mass) that it had AT LEAST MORE THAN ZERO momentum. And both energy and momentum are conserved.
<br>OK, now would you please explain the stopping of the Bankers Trust collapse within the 'terms' of your above quote?
QUOTE (-> | QUOTE | by Schneibster
Stopping would require that it dissipate ALL the kinetic energy at the point during the fall where it stopped; but since it didn't, we know that it had AT LEAST MORE THAN ZERO kinetic energy right to the ground, and that means that (since it cannot ever have had zero mass) that it had AT LEAST MORE THAN ZERO momentum. And both energy and momentum are conserved.
<br>OK, now would you please explain the stopping of the Bankers Trust collapse within the 'terms' of your above quote?
by Schneibster...you don't have to know all the details, as long as you know it kept falling, and as long as you know that energy and momentum were conserved. If you don't find enough energy being released to KEEP it falling, then you've got a case for demolition.
<br>This idea that once a collapse is initiated it must continue is a mantra that is repeated over & over, and is attempted to be 'proven' by all manner of methods.
The one being currently used in this discussion is from the point of view of conservation of energy and conversation of momentum. This is fine when referring to falling bodies, and works out mathematically when reduced to the absolute simplistic terms of a floor (or other object) which is falling through thin air and is unimpeded by any other forces until such time as it impacts another floor (or object).
This does not describe all the events occuring within the collapses at the WTC. It does not account for the resistance provided by unsevered connections, nor the resistance provided by unsevered (or only partially compromised) columns.
The whole 'idea' that 'somehow' the entire upper mass of the building commenced a fall through thin air for 12' (until impacting the lower 'floor') is utterly bogus.
This can not happen in reality.
All of the calculations presented, (as IF at some point, the entire upper mass was set completely free from ALL lower connections and support resistance - thus enabling this fairy tale 12' 'free-fall' of the upper section dynamically impacting the next lower 'section' or 'floor' is where the hypothesis is in error to begin with. This is the initial 'assumption' being made to 'initiate' the falling momentum, and this assumption is wrong (IMHO),
It can NOT happen (in the real world) that... suddenly and instantaneously the entire columnar connections between the upper section and lower section just 'disappear' allowing the alleged 'free-fall' of the upper 'floors/mass' falling down 12' to impact the lower 'floor/mass', thereby commencing the dynamic energy and momentum calculations to proceed... (as if we are discussing a number of 'floating floors' suspended 12' feet above one another, until suddenly one falls down to impact the next... those two then fall down to impact the third, and so on right down to the ground.) like this...
No offense intended, but it seems to me that you (and other supporters of gravity-driven collapse) have been completely brainwashed by the repetition of this 'pancaking theory' promoted over the past 4 years.
As I said this can only plausibly be considered to define and calculate the fall, IF we assume that the towers were a box with truss floors suspended from one perimeter wall to the opposite perimeter wall with no columns in between. Absolutely NO engineers would ever design a skyscraper like that for precisely the reasons your calculations show.
But IF THIS (floors spanning from perimeter wall to perimeter wall) were the case, AND then 'something' (such as catastophic failures of all the truss seats on a number of floors failed virtually at the same time)... THEN, you may have a situation of a number of floors falling to impact a lower floor (thus overpowering the truss seats on that floor) which then falls to the next, and this process leading to the increasing weight of the combined floors then falling to the next, and beginning a process of ever-increasing weight and momentum being applied to the subsequent floors. This is what you are mathematically calculating.
This IS a mathemateical calculation defining an alleged 'progressive collapse'. This 'model' and the calculations being used to define it do not accurately represent the true conditions which had to be met in order to collapse the WTC towers to the ground. This IS the NIST fairy tale of Total Global Disproportionate Progressive Collapse, reduced to numbers.
When people refer to the 'resistance' being offered by the impacted floor, this does not take into account the 'column resistance' which kept these buildings from 'collapsing' for over 30 years.
PS - Please note that when i refer to 'columns' below, I am referring to the post & beam columnar structure that comprised the central core. I don't care, nor is it important whether the perimeter columns fell away. Forget the perimeter columns for a moment, I am referring to the core columns below.
It is not simply the 'resistance' encountered by overloading the impacted 'floor'... (fracturing the truss floor seats) to the point of failure...
...at the same time and speed the entire columnar structure of the lower stories must be overloaded to the point of failure (floor by floor - or 'story by story'. This columnar failure is nothing remotely similar to adding weight of horizontal floors falling onto lower horizontal floors and overloading those.
The 'weight' of the upper columns is acting in compression on the lower columns.
There is NO ADDED dynamic weight being applied to those, (as there is in the case of horizontal floors being piled upon one another). A horizontal floor was not designed to have the weight of all above floors dropped onto it, therefore it that case it is plausible that if such occurs, then theoretically this 'progressive collapse' can proceed according to the calculations presented.
This is NOT the case with the columnar structure. There is no 'added weight' which can be applied to those. The weight was not increased through compression upon those. The upper weight did not suddenly increase to be applied in compression against those lower columns. They had been supporting the above weight for over 30 years.
Even if you allow for the columns (in the impact zone to be overpowered by additional weight somehow and 'buckle'), that still does not increase the weight upon lower undamaged columns to cause them to buckle and fail.
The added 'weight' falling upon lower 'floors' (horizontal structural members) can exceed their design limitations by the amassing of weight in excess of their design limitations, but this 'added weight' scenario does not apply to vertical columns because they were designed to support (not only the mass/weight being exerted upon them for over 30 years), but according to standard design safety factors 5 times that weight.
Now in order to overload one column you must place 5 times the weight upon it that it (ordinarily) was designed to support.
Where does this 'extra' weight come from? If you take weight (previously being supported by 5 other columns) and pile that on the one column to overload it, then you have removed weight from 5 other columns. There is not suddenly 5 times the weight in the above portion of the building to act upon all of the columns. As far as I recall an asteroid did not land on top of the building.
Of course, you will now resort to the appeal for dynamic energy overloads, and again... this is acceptable to horizontal floors being impacted from the alleged dynamic drop of upper floors, but this does not extend to columns. You cannot suddenly 'disappear' 12' sections of all vertical columns in one floor so that 'somehow' there is a dynamic drop of above vertical columns being 'dropped' through a void (or thin air) to dynamically fall on top of lower vertical columns. This is fairy tale nonsense.
| QUOTE | by Schneibster (regarding the core column in the picture below)
...please note that if the column was square, you're looking at something that came from low down in the building, they weren't hollow square columns high up on the building as we already know from multiple sources.
<br>
http://oceanmirage.homestead.com/core_beams.html
If you look on this page http://oceanmirage.homestead.com/core_untitled3.html you will find a copy of page 10 (from the NIST NCSTAR 1-3A, draft report). Fig 2-7 on this page shows the core column lay-out in the WTC towers.
The diagram shows the shape of each column at floor 84. Each column is identified by number in the ovals next to the column representation. Under that oval is another number which (according to NIST) indicates at what floor the column transitioned from 'box' columns to 'wide-flange' columns.
The picture of the column I used, is obviously a 'box' column (rather than a wide flange column), however, it is not readily apparent which column number, or from what level, that column came from. As can be seen from the diagram...
... you can not simply assume that because the column in the picture is a box column, that it must have come from one of the lower floors. This is evident, because; as you can see, column # 803 for example was a box column at floor 84 and allegedly did not transition to a wide-flange column until floor 95. So, with all due respect, your statement that "they weren't hollow square columns high up on the building as we already know from multiple sources" is wrong.
There is another NIST 'mystery' here. Adoucette pointed out some pages back that I proposed the question on the above page...
"Where are these rectangular 12" x 36" Central Core Columns represented in any of the above figures ?"...
As can be seen in the photo this [b]rectangular core column having dimensions of 12" x 36" were much larger than the column numbered 504 (for example), yet it is obvious from the H shape broken off from the top of this rectangular box column that this was where the box column transitioned to wide flange columns.
Although, it is very nice of NIST to present us with the information in Fig 2-7 (and the rest of the information on page 10 of the NCSTAR 1-3A draft report), the seemingly haphazard transitioning of box columns to wide-flange columns at various floors does not give me great confidence that what I am seeing is the absolute truth. Perhaps it's just me and my way of looking at 'blueprints'. In my 40 years of looking at blueprints, I have never yet seen a set of architectural blueprints that I did not find errors in, and when I see a schematic such as shown in the above report (which does not make sense to me) my curiosity is piqued, and leads me to thirst for the full set of blueprints.
As the Silverstein court case has now been settled, I see no reason for the withholding of the full set of blueprints for the towers, The fact that they are still 'secret' (combined with the mass media misrepresentations of the central core) leaves me suspicious as to the veracity of partial representations such as in the NIST reports. According to the construction photo...
http://oceanmirage.homestead.com/core_lg.html
it appears to me that at about the 40th floor all (or at least the vast majority of the central core columns) were these massive 12" x 36" rectangular box columns. Maybe it's just the architectural bent in me, but personally I'd feel more comfortable knowing how and at what floor these 12" x 36" box columns transitioned to smaller box columns. The smaller box columns such as represented in the NIST report also don't make sense because why would they put a square box columns having a greater width than the rectangular columns (such as column 504 which is represented as having a width of 22") ?... it doesn't make any engineering sense at all to me. Is NIST trying to delude us into thinking that the box columns below the wide flange columns were smaller than they actually were? Are they trying to imply there were no larger 12" x 36" columns?
I am afraid that I also disagree with your description and purpose of both the Vierendeel truss and hat truss, but I've run out of steam for tonight and will have to address those another time.
Later.
Zoktoberfest - good point on the explosives issue put forth by Schneibster. Quite 'speculative' (I must say) but nevertheless Scheibsters going through a list of conventional ordinary explosives and detonation procedures as a straw man exercise does nothing for me.
Foxx
1st December 2005 - 09:17 AM
Here is a good reference source for videos of comparative controlled demolitions. Some great shots of demo 'squibs' (and dust clouds) are included... Squibs - Southwark Towers - bottom row (third from left) http://www.implosionworld.com/cinema.htmDust in the Wind... (did you know?) | QUOTE | When the excitement of the blast is over, a large, billowing cloud of dust is one of the most identifiable characteristics of a successful project.
<br>
http://www.implosionworld.com/dyk5.html
metamars
1st December 2005 - 01:40 PM
I just posted the following at 911blogger.com, where some people are discussing the dissing of Professor Jones' paper by the consruction engineering dept. at BYU. Apparently, they are now getting spammed with a lot of '911 Truth', which I don't believe is a very good way to go about things.
==============================
I don't think it's a good idea to present ALL arguments for 911 conspiracy to civil engineering professors or professors in physics, applied math, or other mechanical engineering types of disciplines.
These are typically busy guys who, to put it bluntly, may not really care about 911. If you challenge them to spend a month reading up on 911, they aren't going to do it. But if you point to technical arguments, as presented in the papers of Jones, Trumpman and Hoffman, then they have something that they can chew on.
Even doing this is a bit of a problem, as all three authors mentioned above have essentially presented physics arguments. Besides the problems having different mindsets brings to the problem, wherein a construction engineer might dismiss, out of hand, a qualitative or sem-quantitative argument which has no history of being useful in his/her field, there is an additional problem.
And that is, some ASPECTS of the collapses are not (AFAIK) properly objects of study in EITHER construction engineering OR physics.
I SPECIFICALLY refer to at least 2 aspects of the collapse which are highly damning to the FEMA Fairy Tale version: 1) the extraordinary speed of the collapses (12 - 16 seconds vs. free fall in vacuum speeds of about 8-9 seconds) and their symmetry. (IMO, the symmetry of the collapse of WTC 7 is so perfect it's not even worth arguing about. Thus, questions about symmetry of collapses should start with videos of WTC 7, not WTC 1 or 2.)
I seriously doubt that there has been any extensive study of how a collapse could possibly proceed symetrically and with such and such a speed. Certainly, my interactions with an engineer and an architect convinces me that they are trained only to think about "how do I make the building strong enough to prevent a collapse, or at least delay it long enough such that the occupants can escape?"
The engineer-type (he wasn't a certified engineer) and the architect (my cousin) that I spoke with both had no problem believing that the building SHOULD have collapsed. The architect insisted that the building performed very well.
If this is generally the case, then we are not in a good position to ask for an extensive amount of construction engineers' time to evaluate the collapses. We are essentially asking them to create a new body of theory that will probably not do them any good in their careers, but may well harm it (due to time taken away from more mainstream pursuits, plus any "ridicule factor" that probably does exist)
THUS, IN INTERACTIONS WITH CONSTRUCTION AND CIVIL ENGINEERS, I RECOMMEND AGAINST PESTERING THEM WITH CHALLENGES TO READ UP ON PNAC, 'MUSLIM FUNDAMENTALIST' MUHAMMED ATTA'S FREQUENT CONSUMPTION OF ALCOHOL, STRIPPERS, AND DRUGS AS WELL AS HIS OBVIOUS STATUS AS A DRUG RUNNING INTELLIGENCE ASSET, LACK OF FIGHTER RESPONSE, ETC., ETC. (WHICH THEY HAVE NO EXPERTISE IN, ANY MORE THAN YOUR PAPER BOY). I RECOMMEND GIVING THEM ONLY THE PHYSICS-ORIENTED PAPERS, AND THEM ASKING THEM TO COMMENT ON NOT "WHETHER THE BUILDINGS SHOULD HAVE COLLAPSED" BUT WHETHER THEY CAN EXPLAIN, FROM A CONSTRUCTION ENGINEERING POINT OF VIEW, HOW THEY CAN CALCULATE THE SPEED OF COLLAPSE, AND HOW THEY CAN SHOW, AGAIN VIA THEIR STANDARD TECHNIQUES, HOW THE SYMMETRY OF THE COLLAPSES CAN BE EXPLAINED.
Some of the "arguments" for demolition are considered non-arguments by specialists. E.g., skyscrapers in crowded cities are designed to collapse into their footprints. Therefore, there should not be a big mystery as to why they did. It's probably more of mystery why so much of the rubble fell outside of the footprints. Thus, this is a better question to ask a construction engineer, than it's opposite!
Ultimately, a completely convincing explanation of collapse can only follow from extensive computer modelling. However, I hope that there are shortcuts that might allow construction engineers to get a handle on the speed and symmetry problem. Also, it is beyond my belief (at least at this point) to see why finite element computer simulations could not affordably be done that modelled just a few floors below the collapse zone (as opposed to the whole building - doing so would be prohibitively expensive)
Of course, there are other aspects of the collapses construction engineers cannot or will not approach. The one that they cannot approach, even in principle, is the uber-weird telescoping, powderizing collapse of the surviving "spire". It is unknown to me whether presenting info regarding the spire to construction engineers would pique their interest, or weird them out. No doubt, the answer to that question depends on the individual engineer. HOWEVER, I CERTAINLY RECOMMEND TRYING THIS APPROACH WITH A SUBSET OF CONSTRUCTION ENGINEERS THAT YOU APPROACH, TO GET A SENSE OF WHAT WOULD HAPPEN IN THE GENERAL CASE. Furthermore, if they do give you the time of day on that subject, don't let them escape the issue with a casual comment about camera angles and throwing up dust. I have analyzed this and shown that the spire collapses about 46 feet before emitting any dust. Furthermore, the collapse is caught on video and camera from multiple angles. (see my posts on physorg.com for more info; my username there is metamars)
I'D ALSO RECOMMEND ASKING AT LEAST SOME OF THE CONSTRUCTION ENGINEERS "HOW CAN THE TOP OF THE SOUTH TOWER TILT BY APPROXIMATELY 25 DEGREES, THUS ACQUIRING ANGULAR MOMENTUM, AND THE THE ROATION BASICALLY JUST CEASE? (Conservation of angular momentum implies, at the very least that the top cease to function as a rigid body and/or that there were sufficient unsevered columns to arrest the rotation, which appears impossible from the pictures)
e
1st December 2005 - 04:37 PM
<a href="http://www.sz7h.com/hqjj/20051014105637.htm">保健品</a>
Schneibster
1st December 2005 - 09:09 PM
I found it. The expression for the time, t = √(2d/a), is only valid for the first step because it assumes that the initial velocity is zero. The correct way to derive the impact velocity at each step is v(final) = √(v(initial)^2 + 2ad) Eq. 1 Derivation: v(average) = d/t #Axiom 1, average velocity is total distance divided by time to move that distance a = (v(final) - v(initial))/t #Axiom 2, total acceleration is velocity increment (initial velocity subtracted from final velocity) divided by time to make that velocity change v(average) = (v(initial) + v(final))/2 #Axiom 3, definition of average as arithmetic mean Since both Axiom 1 and Axiom 3 are equal to the same value, set the expressions equal to one another: (v(initial) + v(final))/2 = d/t Solve for d: d = (t(v(initial) + v(final)))/2 Eq. 2 Rearrange Axiom 2: t = (v(final) - v(initial))/a Substitute this value for t into Eq. 2: d = (((v(final) - v(initial))/a)(v(initial) + v(final)))/2 = ((v(final) - v(initial))(v(initial) + v(final))/2a Rearranging, perform the quadratic multiplication: 2ad = v(final)^2 - v(initial)^2 Solve for v(final): v(final)^2 = v(initial)^2 + 2ad v(final) = √(v(initial)^2 + 2ad) #Derivation complete Using this methodology, the following program: CODE
#!/usr/bin/perl
$m = 4285500; # mass of one floor (kg)
$mt = 0; # mass of falling section
$fc = 39; # floor count of falling section (39 floors for 2 WTC)
$v1 = 0; # beginning velocity for the current step
$v2 = 0; # velocity at impact
$v3 = 0; # ending velocity for prior step
$p = 0; # current momentum
$ke1 = 0; # kinetic energy at impact
$ke2 = 0; # kinetic energy after impact
$de = 0; # total energy dissipated so far
$a = 9.80665; # acceleration of gravity (constant)
$t = 0; # cumulative time taken
$t1 = 0; # time taken for this step
$d = 3.8; # distance between floors (418m/110 stories)
$mt = $fc*$m; # initialize mass of falling section
$rfc = 110 - 39; # initialize remaining floor count of uncollapsed floors
while($rfc > 0) {
$v1 = $v3; # starting velocity is ending for last step
$v2 = (($v1**2)+((2*$a)*$d))**0.5; # impact velocity for this step by formula
print("Impact velocity for story ", $rfc, " was ", $v2, "\n");
$p = $mt*$v2; # momentum at impact
print("Impulse delivered for story ", $rfc, " was ", $p, "\n");
$ke1 = ($mt*($v2**2))/2; # kinetic energy at impact
print("Impact kinetic energy for story ", $rfc, " was ", $ke1, "\n");
$fc++; # increment falling floor count
$mt = $fc*$m; # update mass of falling section
$v3 = $p/$mt; # new velocity
print("Velocity after impact for story ", $rfc, " was ", $v3, "\n");
$ke2 = ($mt*($v3**2))/2; # kinetic energy after impact
print("Remaining kinetic energy for story ", $rfc, " was ", $ke2, "\n");
$de += $ke1 - $ke2; # add dissipated kinetic energy to total
print("The kinetic energy dissipated for story ", $rfc, " was ", $ke1 - $ke2, "\n");
$t1 = $d/(($v2 + $v1)/2); # time for this step by formula
print("The time spent collapsing story ", $rfc, " was ", $t1, "\n");
$t += $t1; # add step time to running total
$rfc--; # decrement remaining floor count
}
print("The total time was ", $t, "\n");
print("The total energy dissipated during the collapse was ", $de, "\n");
print("The remaining kinetic energy at the end of the collapse was ", $ke2, "\n");
gives just over 8 seconds (8.81490783917812) fall time, for a deficit of 8.81490783917812 - 7.417808763529092758427200860118 = 1.397099075649027241572799139882 So over the total collapse, 1.397 seconds was used up collapsing each floor, and the rest falling. The dissipated energy during the collapse (that is, the cumulative difference between the kinetic energy at impact and the kinetic energy after impact for each floor) is 231309935644.914J, 231GJ or 64252.759901365kWh, 64,000 kWh more or less. The remaining kinetic energy of the falling material is 607755517184.677J, 6.08TJ or 168820.97699574361111111111111111 kWh, 169,000 kWh in round numbers. Finally, the velocity after impact with story 1 is 50.7787914769006m/s, which indicates that about 30% of the expected velocity was lost cumulatively in the impacts; compare with 72.743854310862577499430109314876m/s calculated for free-fall. This is the most realistic calculation to date: 1. It goes step-by-step through each floor. 2. It uses correct height for the beginning of the collapse of 2 WTC, which began at the 71st story, not at the top of the building. 3. The lost time for each story is derived using conservation of momentum, showing at least part of the time lost at each story collapsing it. 4. Correct kinetic energy figures are derived, and separated by the kinetic energy dissipated during the collapse, and the kinetic energy remaining in the debris at final impact. The following assumptions are made, which might require further review and adjustment of the program, or justification in terms of momentum and energy conservation: 1. There is no resistance between impacts of the falling mass with the next floor slab to be collapsed. 2. It does not take the weight of the debris from the plane into account. 3. The weight of the contents of each floor is EXTREMELY conservative; IMO, it could easily be twice what I have used here, which might decrease the total fall time by perhaps 10%, but increase the dissipated kinetic energy by 50% or more, and the final kinetic energy by a factor of two or more. 4. This methodology assumes perfect inelastic collision between the falling mass and the floor slabs; in reality, it is more likely that the concrete would have had at least some elastic response to the strikes, and this is the factor that makes the highly complex numerical simulations that FEMA has used more accurate than this procedure. In mitigation, however, of the last assumption, whether the collisions are elastic or not, momentum and total energy must still be conserved, so we are looking for additional dissipation of kinetic energy and consequent reduction of velocity, which will then tell us the expected reduction of momentum; this should lead to a realistic general solution. Note that the total collapse time is given as 8.81 seconds; we observe, however, that the actual collapse took as long as 15 seconds, nearly twice this, to as short as 12 seconds, approximately a 1/3 increment over this. This is a strong indication that more kinetic energy was absorbed in the collapse of each story than was needed merely to collapse the floor slabs; this energy presumably was used up bending and breaking the core columns, and their cross-braces, along with the floor trusses and any breaking or bending of the perimeter columns. I'll look into this and see what we can determine to try to figure out some representation of these additional factors to make the program as realistic as possible. The following factors have not been calculated: 1. Complete collapse of the 1 WTC tower, which started on a different floor. 2. Any thermal energy released by the fires. 3. Initiation of the collapse. 4. The perimeter column behavior. Let's see what we can deduce from the results of this equation. I encourage everyone to download perl and install it (it's available for free under the GNU public licence/copyleft for pretty much all major platforms) and run it, to see the actual results floor-by-floor and verify that they are realistic at least to the extent that this model is. metamars, I'll have a look at your program next, before I proceed with an analysis of the likely effects of the changes to the energy budget, and the addition of the above factors into the program to give a yet more realistic result. Everyone, please have a look and see if you find any problems in the algorithm or coding.
metamars
1st December 2005 - 09:57 PM
| QUOTE | Everyone, please have a look and see if you find any problems in the algorithm or coding.
<br>Sorry, big guy, I'm not a perl man.
At least you didn't code it in Chinese.
Schneibster
1st December 2005 - 10:42 PM
heh, well, I'm not a VB kinda guy, so it looks like an impasse. However, I did find it interesting that (if I have understood your results correctly) we derived similar results for total collapse time.
Could you please analyze your program and its results for us and give some commentary on the algorithm you used in more detail? And did you find my comments in the perl program illuminating? Would you like me to justify it line-by-line? I can show the provenance of the equation that each calculation is equivalent to, if you'd like.
adoucette
1st December 2005 - 11:11 PM
QUOTE (metamars+Dec 1 2005, 09:57 PM) | QUOTE | Everyone, please have a look and see if you find any problems in the algorithm or coding.
<br>Sorry, big guy, I'm not a perl man.
At least you didn't code it in Chinese. Ah, come on Metemars, I'm neither a VB or Perl man, but that language is pretty much totally intuitive to anyone who has programmed anything (I'm an old IBM 360 Assembler programmer)
The $ indicates a variable, the initial values being set at the top.
The while($rfc > 0) { .... } is the same as "do while"
The other statements do exactly what the comments indicate.
Arthur
Schneibster
1st December 2005 - 11:34 PM
QUOTE (Foxx+) It is possible that I mispoke, but I do not recall stating anything to the effect that "we cannot know how large the forces were in the building". |
I was paraphrasing your observation that we could not expect to do realistic numerical simulations of the highly complex factors involved in the actual collapse of a complete story. You made this point in your prior post; I'll not quote it because it's rather insulting. Let me digress and acknowledge your apparent acceptance of our "new way of proceeding." I'm going to avoid reading those previous posts, to make sure I don't get nasty; you might have to repost some things in the "new way" to remake some of your points, so please bear with me and accept my regret in advance that you might need to repost some material. My contention is that because of the conservation laws, we can in fact expect to use them to make at least "order of magnitude" calculations, and with some care and a little creativity, likely with 10% or so; despite the fact that we know that we cannot accurately model either the frictional or other dissipative forces, we nevertheless know that no momentum or kinetic energy disappeared or was created by anything but gravity. QUOTE (Foxx+) Again you seem to repeat the mantra that once 'collapse' is initiated, nothing is going to stop it... (it's 'inevitable ! )
This unfounded mantra flies in the face of every other fire-induced steel-framed building 'collapse' in history which WERE only Partial Collapses. There is no need to study all of those to see WHAT caused the cessation of the collapse. |
In fact, the differences in the construction of those buildings is what stopped it. The design of the WTC towers was quite unusual; most tall buildings are built with supporting columns distributed throughout the structure, rather than concentrated in the middle, and do not rely on a distributed Vierendeel truss on the outside of the building to prevent lateral forces from disturbing the support columns, but on either Vierendeel or traditional diagonal trusswork between the support columns themselves. These two factors in the towers' design separated the lateral from the vertical force compensation; IOW, the perimeter columns resisted lateral forces, and the core columns resisted vertical forces, and each protected the other from the type of force it was not designed to resist. In more detail: 1. The distributed Vierendeel truss design of the perimeter columns placed the stress of lateral forces (wind) on the sides of the building parallel to the wind (or over all four sides in a diagonal wind; you can decompose a diagonal force into two components perpendicular to one another and normal to the building's shape, and show that each of these components is resisted by the faces parallel to its direction). This protected the core columns from lateral forces, and allowed their design to consider only vertical forces, making them lighter and also obviating the need for either Vierendeel trusswork or traditional diagonal trusswork between them to resist these lateral forces. Thus, only perpendicular trusses between the columns were needed to keep them from buckling under the vertical force by keeping their length centered under it. 2. The hat truss at the top of the building removed some of the vertical force of their own weight from the perimeter columns and distributed it to the core columns, allowing the spandrels which linked them into a Vierendeel truss and the connections of those spandrels, as well as the perimeter columns themselves, to be lighter than they would otherwise have needed to be, or from a different point of view, increasing the amount of lateral force the spandrel-to-perimeter-column links could absorb by reducing the amount of vertical force they had to distribute. This non-traditional design has not been widely copied, and as a result, I am not convinced that any of us can produce data from the collapse (or non-collapse under similar stress) of comparable designs; data from non-comparable designs, particularly traditional designs that distribute the columns over the entire floor and bear both the lateral and vertical stress on those columns, whether the lateral stress is compensated for with a Vierendeel or traditional diagonal truss design, appears to me to be irrelevant at least in the case of the towers. Such data, however, IS applicable to the collapse of 7 WTC, but unfortunately only if we can determine the extent of the damage to the building on its south face; without this, we have little means of evaluating how that damage might have contributed to the collapse of 7 WTC. If you can produce evidence regarding an incident in a building using this non-traditional design (the "tube in a hollow tube," Vierendeel-truss/core column design of the WTC towers), it would be germane. Do you have any? QUOTE (Foxx+) One example of Partial Collapse (although not caused by fire but rather by 'Amazing Flying Columns' ) occured at Bankers Trust... |
The stresses placed on the perimeter columns by the collapses of the floors are relatively obvious. Early in the collapse, the stresses are sufficiently low and slow that some of the perimeter columns remain standing after the floors they were attached to have already fallen; if you carefully examine the first video on Research 9/11 of the 1 WTC collapse, you'll note that a "spire" of perimeter columns remains standing while the antenna falls past them, on the right; it is partially obscured by smoke, but careful inspection shows that it can be nothing else, and the "3-column 3-story" pattern is visible, along with the spandrel plates. If the force comes onto the floor slab very fast, the couplings to the perimeter columns would not have time to shear before enormous vertical force had fallen onto the perimeter columns, which were not designed to handle heavy vertical overloads; as a consequence, they would elastically bend, possibly not past their yield point, and when the couplings sheared, they would spring back into shape. This would apply enormous force to all their couplings with other column segments, and (since bowing inward would be prevented by the floor slabs, and they would be bent outward), also apply force against any lower floor slabs that had not yet collapsed/been struck, flinging them outward. This explains the "flying columns." In regard to Banker's Trust, this was a highly traditional design, with much greater resistance to external damage than either tower; it is not clear how its design compares with that of 7 WTC, and a comparison would be very interesting. I strongly suspect that the external columns were much more substantial than those on 7 WTC, but I don't have any data to back that up. I'll also point out that we have no idea of the relative numbers of 3-column 3-story perimeter column segments that struck 7 WTC as compared to Banker's Trust. Simply put, I don't think there is sufficient evidence to conclude that either the number of impacts was the same, or that the two buildings would have responded similarly to them; and in the face of the only testimony we have seen, that there was a 20-story hole in the south face (and I don't buy that this is the corner damage, which photographic evidence shows was ten stories at most), and that the elevator shafts were compromised and the elevators fell out of them, I see evidence that there was sufficient damage that it was well within the bounds of possibility that that damage combined with the extensive fires in the building were sufficient to cause its collapse. We need a lot more evidence about 7 WTC before we can come to any reasonable conclusion other than that, and I simply don't see such evidence being presented. QUOTE (Foxx+) A section of perimeter column trees estimated to weigh over 90 tons travelling at free-fall speeds impacted the face of Bankers Trust... but a few (much smaller beams than were in the WTC towers) stopped this massive dynamic impact without 'progressively collapsing' the lower section of building right to the ground. |
The speed was not "free fall" in the horizontal plane. The actual speed would have been a combination of some portion of free-fall, which depends on where in its parabolic descent it was, which would influence the impact angle and therefore what components of horizontal and vertical force would be applied to the building, and its horizontal velocity from the force that snapped it free from the face of the collapsing tower, which would in turn depend on how far down the building it was before it was ejected. Without any indication where it came from, IOW, there is no way to judge its horizontal velocity. Much less is there any way to judge the same for 7 WTC, when we don't even have any picture or description of the perimeter column segment or segments that must have struck it. I made a mistake earlier in applying the vertical free-fall velocity to the falling columns as potential impact speed; I should have noted that this would be the maximum possible speed, not the likely speed. The likely speed would be about half of this, around a hundred miles an hour. I have already noted that we have no data that shows that the construction of Banker's Trust and 7 WTC were in any way comparable, and we know for a fact that Banker's Trust and the towers were completely different designs; in addition, the impact of perimeter columns on Banker's Trust is immaterial to the collapses of the towers, because the perimeter columns would have flown outward, not inward, under the impulse of their elastic recoveries. QUOTE (Foxx+) OK, now would you please explain the stopping of the Bankers Trust collapse within the 'terms' of your above quote? <br>First Banker's Trust and the towers were completely different designs, as noted above. Second, there is no evidence that there was a fire in Banker's Trust of the magnitude of the fires in either 7 WTC or the towers. The picture alone is sufficient to establish that there in fact could not have been, at least not before that picture was taken. Third, there is no evidence either in that picture or elsewhere that Banker's Trust ever started to collapse, much less was stopped in mid-collapse. Please show the relevance of the effects on a building of completely different design of a potentially completely different impact to the current conversation, other than to demonstrate that there were perimeter columns flying around with considerable force. QUOTE (Foxx+) This idea that once a collapse is initiated it must continue is a mantra that is repeated over & over, and is attempted to be 'proven' by all manner of methods. |
The program I have posted and the derivation of the equations used to create its algorithm is sufficient IMO to show that it is not a "mantra," but a fact. If you have any question as to the provenance of those equations, the correctness of their derivation or application, or the correctness of the program or its algorithm, please post it in detail. I need to stop and point out that I consider the use of "mantra" in this context an insult. The reason is because it implies I am accepting statements without examination or evaluation; the truth is, I am being highly critical of anything that I accept from any source whatsoever, and have made extensive supporting documentation available, as well as the sources of all my physics calculations. Please do not imply again that I am uncritically accepting anything whatsoever; if you believe that I have accepted something without examining it, please point it out in detail and ask me to support it. This will permit me to either acknowledge that I have in fact done so, and either support it or repudiate it and look for the truth based on evidence, or present the grounds for it for the examination of all. I am neither stupid nor uncritical; it is my practice to be highly skeptical and extremely detail oriented. I would appreciate it (since it has to be obvious given what else I have posted) if you would acknowledge this and avoid such inflammatory language in the future. QUOTE (Foxx+) The one being currently used in this discussion is from the point of view of conservation of energy and conversation of momentum. This is fine when referring to falling bodies, and works out mathematically when reduced to the absolute simplistic terms of a floor (or other object) which is falling through thin air and is unimpeded by any other forces until such time as it impacts another floor (or object).
This does not describe all the events occuring within the collapses at the WTC. It does not account for the resistance provided by unsevered connections, nor the resistance provided by unsevered (or only partially compromised) columns. |
I need to stop here and point out that both energy and momentum are conserved quantities, though they are not jointly conserved, and though kinetic energy is not a conserved quantity since it can do work and thus be converted into other types of energy (and ultimately into heat). As a result, it is possible to unambiguously know the total energy available after a falling section of building has fallen for a certain distance, although it is not possible to be absolutely certain precisely how much of that energy was dissipated and how much remains in the falling section; similarly, it is possible to unambiguously know that if the falling section remains falling, the total momentum of all falling objects will be determined only by their mass and velocity, and not what interactions they participate in. Using these well-founded assumptions, it is therefore possible to show what is possible and what impossible, because it would violate one of these conservation laws. This is one of the most important facts of physics; you can know before you begin that these conservation laws will be rigidly adhered to in all details of an interaction, no matter how complex. If this were not so, physics would be impossible, and magic would be the rule. QUOTE (Foxx+) The whole 'idea' that 'somehow' the entire upper mass of the building commenced a fall through thin air for 12' (until impacting the lower 'floor') is utterly bogus. |
Ahhh, but we DO know for certain that after it has fallen 12 feet, all the reduction of potential energy represented by that fall will have been converted into real energy of some kind. Since we know the mass, we can convert the reduction in potential energy to average velocity of all the components, and if some components can be shown to have remained intact, if we can get a good estimate of their mass, we can derive their kinetic energy from that, as well as their momentum. This is highly useful if we wish to establish whether the gravitationally driven collapse of the towers is possible or impossible. It may not be enough to show the details of the collapse, but it is certainly sufficient to prove it impossible if it in fact is. I believe I have shown sufficient evidence to refute the statement that it is impossible. Here is another thing that could be taken badly (although it is not nearly as overtly insulting as asserting that I have uncritically accepted statements without supporting evidence): please don't use "bogus" in this manner. I suggest also that if converted into more acceptable language, such as "unsupported by the facts at hand," you have not presented sufficient supporting evidence, such as specific criticisms of the equations, either their correctness or their correct application, to make this assertion. Please do so or abandon it. QUOTE (Foxx+) All of the calculations presented, (as IF at some point, the entire upper mass was set completely free from ALL lower connections and support resistance - thus enabling this fairy tale 12' 'free-fall' of the upper section dynamically impacting the next lower 'section' or 'floor' is where the hypothesis is in error to begin with. This is the initial 'assumption' being made to 'initiate' the falling momentum, and this assumption is wrong (IMHO), |
I have explicitly excluded the initiation of the collapse from this calculation; my entire intent was to show that once started, collapse was indeed inevitable. The assumptions I have made are not hidden, I have attempted to be completely transparent and revealed all of them I was aware of. I'll point out again that once we know that a 39-story section of the building has fallen 12 feet, we know that the potential energy of that section has been reduced, and that all of that has appeared as kinetic energy and is either retained as such in the falling mass, or has done work and been converted to heat or vibrational energy of one kind or another (sound, compression of elastic components that will later recover and re-release the kinetic energy in a different direction, shaking, crushing, or permanent deformation due to the materials' yield strength being exceeded). And we cannot deny that this section has fallen twelve feet, nor that its potential energy has been reduced thereby, nor finally that all this reduction of potential energy has been converted to real energy of some form. It is my intent to examine this first story's collapse in much greater detail before we are done. However, given that it DID happen, we know for certain that a certain amount of potential energy was lost, we know for certain that that amount of real energy has been released by whatever means. The details are unimportant at this point, because we are not analyzing HOW it was released, or WHY it was released. I should point out that it remains possible (though IMO extremely unlikely given other objective factors that I have already discussed) that this initial story's collapse was not "natural." I have little doubt that we will establish whether it is possible without further interference than the impact of the plane and the burning of its fuel and contents, and the burning of the material on that story, before long, and I counsel you to patience. We have other fish to fry at this point. I must point out another inflammatory piece of language: "fairy tale." I'd appreciate it if you'd avoid such language and stick to critical analysis based on facts. Please point out how you believe that the above analysis is incorrect without the use of biased language, in terms of its content, the correctness or incorrectness of the equations used, or their application to the situation. QUOTE (Foxx+) It can NOT happen (in the real world) that... suddenly and instantaneously the entire columnar connections between the upper section and lower section just 'disappear' allowing the alleged 'free-fall' of the upper 'floors/mass' falling down 12' to impact the lower 'floor/mass', thereby commencing the dynamic energy and momentum calculations to proceed... (as if we are discussing a number of 'floating floors' suspended 12' feet above one another, until suddenly one falls down to impact the next... those two then fall down to impact the third, and so on right down to the ground.) like this... |
The obvious fact is that one story collapsed first, based on the video record. No matter what the details of that collapse, a known mass has moved from one position in a gravity field to another position, and this change of position has resulted in a change in potential energy; since the change is negative, we know through conservation of energy that the missing potential energy has appeared as real energy of some form or another. The current assumption is that all of this energy change has appeared as kinetic energy. This shows that there is sufficient kinetic energy involved to drive the collapse of the next floor; since my statement was, "once it started, it was inevitable that it would all collapse," I have utilized this means to show that it is not IMPOSSIBLE that there was sufficient energy to drive the collapse forward once it started; I have explicitly not made statements regarding the initiation of the collapse. I also have to point out that we know from the video record that the core was compromised in both collapses. The evidence that this was so is unmistakable. When the top of 2 WTC "bent over," this applied lateral force to the core that it was not designed to handle (the lateral force was all supposed to be handled by the perimeter columns). When the antenna tower at the top of 1 WTC leaned over, it was also clear evidence that the core had given way, since that antenna was mounted to the hat truss, and the hat truss was mounted to the core. Again, I'll discuss collapse initiation later; but the facts are undeniable: so much mass moved down through so much distance, and so much potential energy disappeared and was converted to real energy. This is simply brute physical fact, clearly visible on the video and clearly apparent in the most basic axioms of physics. Once this energy was available, it was sufficient to drive the remaining collapse, is the contention I base on these facts, and I have given extensive evidence to support that assertion. Do you have any evidence to present that denies that there was sufficient energy? If so, you have not presented it here; you have merely made an unsupported assertion, repeatedly. Repeating it does not support it; you have to substantiate it through evidence. Please do so, or again, abandon it. QUOTE (Foxx+) No offense intended, but it seems to me that you (and other supporters of gravity-driven collapse) have been completely brainwashed by the repetition of this 'pancaking theory' promoted over the past 4 years. |
In fact, I am showing clear and compelling evidence to support it, not merely making unfounded assertions. If you wish to provide evidence to support this position, I am willing to listen (as long as it is presented in a respectful manner). But to do so, you must provide compelling evidence that the assertions that energy is conserved is incorrect, or that the equations I have used are either incorrect or incorrectly applied, and I do not have any reason to believe that this is true, and in the first case I have extremely strong reason to believe that it is impossible.
While not insulting, I have to point out yet again that you are clearly of the opinion that I and others are accepting the assertions of yet others uncritically, but you have not provided any evidence to support that contention. I am in fact engaged in critical examination of the physical facts, and clearly have been for quite some time including well prior to my appearance in this forum, and the conclusions I have come to and am coming to do not agree with your opinions. I have to point out that I believe that the grounds on which you are critical of these theories are not based on examination of their assertions or foundation, but on your personal emotional desires; however, I do not ACCUSE you of this since I do not assume I have seen all your evidence yet. I merely observe that the evidence you have presented so far is minimal, whereas the assertions you have made are extensive. In my experience, this stems from emotional factors overriding intellectual ones. I strongly recommend careful, unbiased critical thinking as an antidote to overly emotionally driven procedures that result in the use of insulting language and assumptions. I must point out that I don't like these conclusions any more than you do; I would be far more comfortable thinking that this might lead to getting rid of the fools who are currently running things, than (as I do) that getting rid of them is no simple proposition of showing that they committed an overt act.
I have personal business and business business to transact; I'll come back to the remainder of your post when I am done.
I note that so far, your tone has changed somewhat, although not to the extent that I desire; you are, however, making an effort, and I acknowledge it and thank you for it. It is not my intent to be insulting or belittling to you in the comments I have made here; I am pointing out places where the problem started in the first place. I suggest that you review what you are posting for inflammatory language prior to posting it, and avoid emotionally-based reasoning which leads to the use of such language in the first place. You will be far better served in your objectives to stick to rationality and careful and critical analysis. I look forward to further improvements which you seem motivated to undertake. Please feel free to express yourself if you feel the need; if you find something insulting, air it so that it can be dealt with plainly and transparently. I assure you that my intent is not hostile, and I think that it will be obvious that this is the case from the tone of this post.
Foxx
2nd December 2005 - 02:17 AM
Heh... [Point 1]...Ooooo...Kay, Schneibster... It seems we are are making progress... and I thank you for your attempt to correct your previous caustic and insulting attitude, and will continue to 'reward you' ( ) with attempts on my own part to avoid 'inflammatory allegations'. Joking aside... please recognize that 'words' posted in 'black & white' (in the impersonal format of 'internet chat'), are always open to various interpretations of the language in which they are spoken; and to a great extent, it depends upon character, experience, personality, and the viewpoint of the recipient as to what those words signify to the recipient and how they receive them. This (in my view) is one 'failing' of the internet. When speaking face to face with someone else (in the 'Real World'), we not only receive the words spoken, but also have the advantage of perceiving numerous other 'clues'; which help us to understand the true meaning (and intent) of the words we are hearing, such as... inflections and intonations of speech or words...
body language & facial expressions of the speaker...All of these important psychological clues (as to the true meaning of the 'black & white' words spoken) are missing in internet chat forums, so it is quite easy to misinterpret the 'motive' or actual meaning of the 'words' one reads. Please be so kind as to recognize this fact. I thank you for abandoning your previous 'troll attitude' of modifying my 'username' and have reverted to addressing your posts to me as Foxx. As much as you like to accuse others of 'insults', I think you now see that this tactic (of modifying usernames) is also 'insulting'. As you are fond of pointing out... "Don't 'insult' me, and you won't get 'insulted' in return". Insulting one another is a 'game' which leads nowhere, and I attempt NOT to purposely insult any other human being ...(regardless of how much of an 'idiot' I think they may be). I realize that... (conversly), you also think that I (or anyone else who disagrees with you) is also an 'idiot', so let's put aside the accusations of 'insults'. (Get a Life, buddy ! ) In my view (although you may have a psychological aversion to being referred to as an 'idiot'), I don't mean the 'title' to be 'insulting'. I refer, in 'face-to-face' conversations with some of my best friends (and vice-versa - with tongue-in-cheek) as to the other being 'an idiot' . Neither (of us) views this 'appendage' (in context) as an 'insult', because we have the advantage in personal face-to-face conversations to 'know' we are just ribbing the other (based upon the psychological clues noted above). As I view it, you are getting far too carried away with perceptions that...' anyone who disagrees with you, is 'insulting' you '. Sheesh !!! Give it a rest, man. Lighten-up ! That is one great ['long' - (covering MANY ISSUES)] essay you have posted above, and requires me to address numerous issues. I will attempt not to avoid any, but... I cannot address everything you have put in that post with a few simple sentences. It will take numerous posts to address each separate issue. Please bear with me, and I will try to address each as a separate issue. Also, please recognize that I do NOT 'accuse' you of being 'wrong' in the calculations you have presented... But, (i believe) there is something 'wrong' with the initial 'assumptions' in analysing these 'collapses'. I do appreciate your input to this discussion, and certainly do NOT view 'you' as a Complete Idiot... (although I reserve the right to call you an 'idiot'; without meaning to insult you), in areas where we disagree. Please feel free to return the favour.
Schneibster
2nd December 2005 - 03:47 AM
Foxx, you will note that at least three other people have commented on your insulting style of communication. While I am willing to be tolerant to a certain extent, that extent is not unlimited, nor is the tolerance; in fact, considering the implications of what you are saying in your most recent post, that extent and that tolerance are EXTREMELY limited. I am not tolerant of those who refuse to accept responsibility for their actions or words. Further repetitions will result in my ceasing to read what you write and respond to it without further warning. I recommend that you be extremely formal, or that you accept responsibility and agree to do something about it; what I'm hearing from you is that you DO NOT accept responsibility and DO NOT intend to change anything, and if that is the case, this conversation is nearly at a permanent and irrevocable end; it will in fact end at my next perception of an insult without further warning and without opportunity for you to discuss it in any way whatsoever with me.
The fact that I am not hostile does not imply that I am not very, very guarded with you. I do not trust you, and it will take a very great deal of effort on your part before I ever will. At the first sign of a problem, I will cease to pay any attention to you whatsoever.
If you'd like somewhat more leeway than that, EARN IT. You have not so far, and the post I am responding to here has used up essentially all the credit you had left on denial of responsibility and refusal to change objectionable behavior. I suggest you reconsider.
yesitdid
2nd December 2005 - 04:00 AM
| QUOTE | The expression for the time, t = √(2d/a), is only valid for the first step because it assumes that the initial velocity is zero.
<br>The expression is usually given as
d = d(0) + v(0)t + 0.5at^2
where d is the distance travelled
d(0) is the starting distance from the measurement origin
v(0) is the initial velocity
a is the accelleration
and t is the elapsed time
d(0) is often zero since we often assume our starting point to be the point of origin
v(0) is sometimes zero as well as in the case at the beginning of the collapse
Note that the calculus derivative of the above formula wrt to t would be
d/t= v(0) + at
which is of course the formula for finding velocity
Note also that in the first formula if we assume d(0) = zero then we can rewrite it as 0=(-d)+ v(0)t + 0.5at^2
this is a quadratic equation and thus can be sovled by any 11th grader who has paid attention in math class.
So, in the first drop the distance is 4 meters and v(0)=zero and the accelleration due to gravity is 9.8m/s^2
(note my nomenclature of s^2 or t^2 means 'seconds squared' and 'time squared')
so 4=0.5(9.8)t^2 , solving for t gives t=sqrt(4(2)/9.8) Once you know how long it took you can calculate the velocity after 4 meters fall.
(there are other shortcuts to take that arrive at the same answers, but I try an keep things simple)
BUT in the next drop v(0) will not equal zero and the quadratic equation will now rear its ugly head.
THIS is what I was doing and I believe what Schneibster was also doing (I think, it has been a very long time since I wrote any code and then it was Basic and Pascal)
Foxx
2nd December 2005 - 04:16 AM
| QUOTE | Originally posted by 'metamars'
I don't think it's a good idea to present ALL arguments for 911 conspiracy to civil engineering professors or professors in physics, applied math, or other mechanical engineering types of disciplines.
<br>Exactly so, 'metamars'.
There are so many 'scientific', 'political', & 'other' anomalies associated with the events (psyopts) of 9/11... that to try to reduce then 'ALL' to one simplistic analysis of WHAT occurred on 9/11 to one field of scientific investigation is... pointless.
There are so many 'things' which do not fit the 'official version of events' that one must concentrate on just one aspect of the anomalies to 'investigate' such anomalies.
While 'investigating' one aspect, the whole scenario must be taken into account and put in context.
Some of us (like Team 8 +) investigate the anomalies and discrepancies of the flightplans... and others investigate the suspicious financial trade transactions with the stock exchanges anomalies.
Still others (like Ruppert investigate other aspects)...
If anyone has 'eyes', they see that 'something' is very wrong with the official version of 'events'.
Anyone who disagrees that there is a NEED for an Independant Investigation of facts related to the events of 9/11... is either 'blind' or 'complicit' with the 'cover-up' of such facts.
I (for one) call for the 'forgiveness' of those who have been 'duped'; but also will call for those who are 'responsible' to be held accountable.
Hang 'em from the yard arms, (I say) !!!
Just my 'opinion'
Schneibster
2nd December 2005 - 04:23 AM
QUOTE (yesitdid+) THIS is what I was doing and I believe what Schneibster was also doing (I think, it has been a very long time since I wrote any code and then it was Basic and Pascal) |
Yes, it is, on my part. I'll offer again to provide further illumination in more traditional math notation of the meaning of the operations in the program, if it will help you understand it (I am of course offering to you for the first time, but I have already offered to metamars) so that you can look it over for errors. QUOTE (yesitdid+) BUT in the next drop v(0) will not equal zero and the quadratic equation will now rear its ugly head. |
Luckily it is tractable despite being a second-degree polynomial.
Foxx
2nd December 2005 - 04:56 AM
QUOTE (Schneibster+Dec 2 2005, 03:47 AM) Foxx, you will note that at least three other people have commented on your insulting style of communication. While I am willing to be tolerant to a certain extent, that extent is not unlimited, nor is the tolerance; in fact, considering the implications of what you are saying in your most recent post, that extent and that tolerance are EXTREMELY limited. I am not tolerant of those who refuse to accept responsibility for their actions or words. Further repetitions will result in my ceasing to read what you write and respond to it without further warning. I recommend that you be extremely formal, or that you accept responsibility and agree to do something about it; what I'm hearing from you is that you DO NOT accept responsibility and DO NOT intend to change anything, and if that is the case, this conversation is nearly at a permanent and irrevocable end; it will in fact end at my next perception of an insult without further warning and without opportunity for you to discuss it in any way whatsoever with me.
The fact that I am not hostile does not imply that I am not very, very guarded with you. I do not trust you, and it will take a very great deal of effort on your part before I ever will. At the first sign of a problem, I will cease to pay any attention to you whatsoever.
If you'd like somewhat more leeway than that, EARN IT. You have not so far, and the post I am responding to here has used up essentially all the credit you had left on denial of responsibility and refusal to change objectionable behavior. I suggest you reconsider. <!--QuoteBegin--> | QUOTE | Originally posted by Schneibster
I am not tolerant of those who refuse to accept responsibility for their actions or words. Further repetitions will result in my ceasing to read what you write and respond to it without further warning
<br>I must inform you that in view of your threats... I am trembling in my boots.
"Idiot" ... you just don't seem to 'get it'.
As I have advised you before... I am NOT 'forcing' you to read my posts.
Again I suggest you seek psychological help. Am I 'insulting' you again? No !!!
Just trying to propose my 'best advice' to you.
Please try to get a life 'cowboy'... you are exhibiting signs of serious psychological abnormal traits.
QUOTE (-> | QUOTE | Originally posted by Schneibster
I am not tolerant of those who refuse to accept responsibility for their actions or words. Further repetitions will result in my ceasing to read what you write and respond to it without further warning
<br>I must inform you that in view of your threats... I am trembling in my boots.
"Idiot" ... you just don't seem to 'get it'.
As I have advised you before... I am NOT 'forcing' you to read my posts.
Again I suggest you seek psychological help. Am I 'insulting' you again? No !!!
Just trying to propose my 'best advice' to you.
Please try to get a life 'cowboy'... you are exhibiting signs of serious psychological abnormal traits.
Originally posted by Schneibster
Further repetitions will result in my ceasing to read what you write and respond to it without further warning
<br> Without further 'Warning' ...(OMG !!!)
Whoooooeeeeeee!!!!
Warning... Warning... Warning !!!
Idiot Alert !!! The Scheibster will NOT read my posts !!!
OMG - I am Devastated !!!
Does anyone else feel 'threatened' by such internet threats???
yesitdid
2nd December 2005 - 05:10 AM
| QUOTE | Idiot Alert !!! The Scheibster will NOT read my posts !!! [
b]OMG - I am Devastated !!![/b]
<br>Ahh, now Foxx understands just how I felt when he was refusing to read my posts.
Foxx, I was at that time just as devastated as you now are.
metamars
2nd December 2005 - 05:11 AM
| QUOTE | "Idiot" ... you just don't seem to 'get it'.
As I have advised you before... I am NOT 'forcing' you to read my posts.
Again I suggest you seek psychological help. Am I 'insulting' you again? No !!!
<br>Honestly, Foxx, what good can come out of posting insults like this?
Schneibster
2nd December 2005 - 05:48 AM
Just precisely what I expected.
It's not a threat. It's a fact. Good bye.
Schneibster
2nd December 2005 - 06:13 AM
Zoktoberfest, several plausible explanations have been advanced to explain the "flash;" among them, a specular highlight and static electricity built up on the plane by flying through the air are the two most likely. 9/11 review asserts the theory that the flashes were caused by the vaporization of aluminum in the leading edges first of the nosecone, and second of the engines, just as they hit the wall of the building. Neither 9/11 review nor I consider other, more esoteric explanations, such as those advanced here, particularly likely, especially considering that it was another hour before the collapse occurred, and the objections about explosives and detonators and so forth not surviving are far stronger for any explosives aboard the plane than any already in the building on the floors where the collision and subsequent collapse occurred. The, I'll dub it, "elevator theory," is pretty madcap. Particularly considering that the shafts were acknowledged to have been damaged along with the emergency stairwells in the collision. If they weren't, how come there were so many people trapped above the impact sites? If the stairwells are blocked, why don't the firemen try to get up there in the elevators and rescue them? Simple, because the elevator shafts are blocked too. In any event, this is sheer speculation; no supporting evidence save the "flashes" (which even other "9/11 truth" advocates don't acknowledge as being evidence of anything unusual) has been offered. If you have some, please provide it.
Schneibster
2nd December 2005 - 06:33 AM
Hey Reality, thanks for stoppin by. QUOTE (Reality+) If, as I read, the 'HAT TRUSS' was 'tensioning' the EXTERNAL columns (because they were half-hanging, as it were, off the hat truss) then as soon as the hat truss support ended, the previously-TENSIONED outer colums would be 'rebounding' DOWNWARDS and PULLING on the FLOOR TRUSSES and CORE COLUMNS. |
Interesting idea. I'm thinking about it. Basically, what happened was that when the top X floors of the building collapsed, the hat truss went down with them; I was unable to find a good view of what was happening in the 2 WTC collapse with it, but in the 1 WTC collapse you can follow it down because of the antenna and it's clear that, for at least the first couple of floor collapses, it stays on top of the building roof (after that, it starts to fall faster, or more accurately, the outside slows down, presumably as a result of the collision with the next floor slab, as one can tell because the antenna starts to topple and starts to disappear into the roof). By that time, I'm pretty sure it's unnecessary. But I'm gonna take a break and go think about it some more, so more innacoupleminnits. I consider it quite a bit more likely that the elastic recovery compromised joints between the floor slabs and perimeter columns, possible that that might have weakened the joints between the floor slabs and the center columns, and again pretty probable that it would have damaged some of the Vierendeel truss connections between spandrel plates or between column sections. For dang sure, it didn't help none. This is gonna require a longer think. It might be more complicated than it sounds at first. VERY interesting idea. I'll make another post after I've mulled it over a while. QUOTE (Reality+) If the outer walls had been 'weaker' (ie, just 'facade' rather than for such structural purpose), then any collapse debris would NOT have been 'contained' within the outer perimeter walls FROM ALMOST THE FIRST FEW MOMENTS TO THE LAST. |
It's possible, but also if they had had more columns, they might never have started to collapse. However, it is also important to point out that they were very tall, and it is entirely possible that they could not have been built with more columns, or with weaker outside walls (because of the need for more columns and for much more trussing between them).
Schneibster
2nd December 2005 - 06:42 AM
metamars, your questions in the "long post" at the end (but for that weird link post by unregistered "ww") of page 78 need some answers. I'll try to get something done about that tomorrow. Bed... sleep... zzzzzz
Guest
2nd December 2005 - 05:27 PM
From a laymans point of view.
Scheibster is either a shill or has the serious emotional problem that many have when faced with the shocking truth that the official tale of September 11 is a complete and utter lie from start to finish. The odd thing about Scheibster, if the latter is the case, is the lengths he is prepared to go to in his denial.
Foxx recently pointed out AGAIN how the presence of the central core collumns means that total collapse was impossible in the manner the collapse took place. These collumns were designed to support the structure a number of times over and there was no added force once the collapse was initiated, the core collumns would therefore have arrested and deflected the upper portion. Not only that, we have visual evidence that the load was significantly reduced with much of the pulverised upper portion falling outside the perimeter of the buildings. Leaving aside what caused the pulverisation of the building the core collumns were under a great deal less stress than before the intiation of collapse.
His explanation of the "hot spots" beneath the buildings is another example of the lengths he is prepared to go to back up the fairy tale or deny the reality.
yesitdid -not of any import but his quaint proposal that Bush was referring to the second plane hitting the building is of another dimension. We are then asked to believe Bush has seen the first tower on fire but on seeing the second plane offers the "must have been a poor pilot" quip.
Its appears easy to get mixed up in the minutae of the physics but the reality is staring anyone who takes the time to examine the evidence straight in the face - not only is the official tale absurd it is that mind blowingly so I can only imagine that in pre internet times such slapstick ventures would not have been so easily exposed.
adoucette
2nd December 2005 - 10:10 PM
You know how you can tell that your posts are hurting their conspiracy theories?
They call you a shill.
Arthur
Foxx
2nd December 2005 - 10:41 PM
As promised... Regarding the structural damage to the perimeter columns... and Schneibsters 'explanation' of Vierendeel action of those columns. He is correct in his description of how the Vierendeel action of the perimeter frame distributed wind loads, but speaking way beyond his knowledge when he begins to extrapolate how the impact damage to the perimeter columns / Vierendeel truss structure performed after the aircraft impacts. Basically, he has stated that because the perimeter columns were severed at the impact zone, subsequently they were 'hanging' suspended from the hat truss assembly. Here is one of his quotes regarding this erroneous thinking... QUOTE Originally posted by Schneibster
Don't invoke the perimeter columns, either, because we all know from the Vierendeel truss design paradigm that we know from multiple sources they fulfilled didn't involve them participating in holding up the floors; they were in fact held up by the core, via the hat truss. <br>Quite a 'popish' statement, which is either purposely meant to mislead OR is an indication that he just makes up his engineering theories as he goes along. Amazing engineering logic... the perimeter columns 'were held up by the core via the hat truss'... Bwahahahahahaha This might very well seem 'reasonable' to those who have no experience in structural design. e.g.... if you have a number of columns standing as a wall or fence, and then remove a section of those columns, one normally would think that now those columns are no longer supported from their base, so the only way the upper portion of the column can remain is if somehow they are supported from the top... right? WRONG !!!To think such is to display a lack of understanding of the structural aspects of a Vierendeel truss framework, and how loads are redistributed in the event of a hole being punched in the 'wall'. In actual fact, the 'wall' is more like a solid piece of steel with holes punched in it for windows. One should not think of the perimeter columns being 'simple independant columns'. The 52" deep spandrels welded to these columns acted like 'belts' which wrapped the whole circumference of the building, tying these columns together like a mesh netting. The perimeter columns no longer act as simple vertical columns, but as a Vierendeel truss wall. Description of a Vierendeel TrussQUOTE (-> | QUOTE | Originally posted by Schneibster
Don't invoke the perimeter columns, either, because we all know from the Vierendeel truss design paradigm that we know from multiple sources they fulfilled didn't involve them participating in holding up the floors; they were in fact held up by the core, via the hat truss.
<br>Quite a 'popish' statement, which is either purposely meant to mislead OR is an indication that he just makes up his engineering theories as he goes along. Amazing engineering logic... the perimeter columns 'were held up by the core via the hat truss'...
Bwahahahahahaha
This might very well seem 'reasonable' to those who have no experience in structural design. e.g.... if you have a number of columns standing as a wall or fence, and then remove a section of those columns, one normally would think that now those columns are no longer supported from their base, so the only way the upper portion of the column can remain is if somehow they are supported from the top... right?
WRONG !!!
To think such is to display a lack of understanding of the structural aspects of a Vierendeel truss framework, and how loads are redistributed in the event of a hole being punched in the 'wall'. In actual fact, the 'wall' is more like a solid piece of steel with holes punched in it for windows. One should not think of the perimeter columns being 'simple independant columns'. The 52" deep spandrels welded to these columns acted like 'belts' which wrapped the whole circumference of the building, tying these columns together like a mesh netting. The perimeter columns no longer act as simple vertical columns, but as a Vierendeel truss wall.
Description of a Vierendeel Truss
Members, or parts, of a normal truss are connected by pin joints (small connections consisting of a pin therough the ends of two members, the pin holds the members together but allows them to rotate relative to each other. If the members of a truss form a square with the joints (corners) free to rotate, the truss could easily be pushed into a parallelogram. Thus normal trusses have diagonal members that connect connect opposite corners of the square (see Fig 2a) and make the truss look like a set of interconnected triangles. The diagonal members prevent the other members from rotating relative to each other. As shown in figure 2b, a Vierendeel truss, or moment frame, has no diagonal members, only vertical and horizontal members that form squares or rectangles. The strength of the Vierendeel truss is in its connections, which are robust & strong. They are fixed joints (not free to rotate) that give the moment frame the ability to resist lateral loads, meaning that the square shape cannot be pushed into a parallelogram. The engineers who designed the WTC towers used a Vierendeel truss system for the perimeter tube so that diagonals would not cut across the windows.
<img src='http://oceanmirage.homestead.com/files/truss0b.jpg' border='0' alt='user posted image' />
source: http://132.236.67.210/engrc350/EngrWords/i...vensonC_PR1.pdf
As I previously stated, Schneibster has essentially got the wind-loading properties of the Vierendeel truss action correct, but is sadly missing another extremely important action that this Vierendeel truss wall provided after the aircraft impact, which leads to his erroneous description of how (after the impacts) the perimeter columns above the impact were 'hanging' from the hat truss assembly. Nothing could be further from the truth. This is an erroneous assumption which he begins with, and then develops a long winded theory of how these 'hanging' columns then became a 'liability' straining upon, and putting massive loads on the hat truss. I'm sure his theory sounds quite reasonable to those who aren't employed in engineering or fields related.
In fact, the Vierendeel truss assembly was WHAT kept the building from at least partially collapsing immediately after the impact, and here's why and how...
Because the columns were tied into this Veirendeel truss assembly, after the impact and severing of 30 or so columns the loads which were normally supported by those columns were directed around the hole. This does not mean to say that the wall was not weakened AT ALL by the hole, but many exaggerate to the extreme the actually weakening of that wall by the hole. YID has often stated that because this hole was present the opposite wall was in extreme tension, and this error comes from the same erroneous thinking that Schneibster is presenting.
In actual fact, because the loads were redistributed around the impact hole the building (had it not been demo'd) could have stood indefinately with this hole in the wall - until the building was compromised by some other extreme event such as a 140 mph hurricane or relatively large earthquake.
No engineers even suggest that this hole was contributory to the 'collapse'. FEMA even provided a diagram which shows how this Vierendeel truss wall redistributed the loads...
As indicated, only a small portion of the columns directly above the impact hole were 'hanging' in tension.
Because of the Vierendeel action the majority of the loads were redistributed around the hole such that little to no additional loads were placed upon the hat truss directly above the hole. In actual fact, the loads on the building were no greater with this gaping hole in one side than loads imposed under heavy wind loads...
Now, hey don't just take my word for the above exposure of Schneibsters erroneous thinking... here are numerous quotes which support the truth of all the above including a couple from NIST...
| QUOTE | Those structures played another lifesaving role as the jets, 156 feet from wingtip to wingtip, each tore out about 35 exterior columns before plunging inside. Because of their close spacing and tight connections, the surviving columns on each damaged face instantly formed a kind of arch — the technical term is a Vierendeel truss — over the holes and prevented an immediate collapse.
<br>http://jman5.com/wtctowers.htm
QUOTE (-> | QUOTE | Those structures played another lifesaving role as the jets, 156 feet from wingtip to wingtip, each tore out about 35 exterior columns before plunging inside. Because of their close spacing and tight connections, the surviving columns on each damaged face instantly formed a kind of arch — the technical term is a Vierendeel truss — over the holes and prevented an immediate collapse.
<br>http://jman5.com/wtctowers.htm
And their columns, Klemencic says, were very closely spaced—only 40 inches on center compared with a distance of 30 feet on center on a typical high rise. “All the columns and all the beams on the face of the buildings were welded together,” Klemencic continues. “When the plane created this hole in the side of the buildings—and photographic evidence says that the hole was about 140 feet wide—a vierendeel truss developed.
“In other words, the building was able to span around this big gaping hole and redistribute the load of the building and carry it to the ground. Without this design, the initial impact would have caused at least a partial collapse of the tower.”
( Klemencic is the current president of the engineering firm that designed the World Trade Center )
<br>http://www.graduatingengineer.com/articles.../01-11-02a.html
| QUOTE | Therefore, the exterior tube of the building was essentially a solid piece of steel with holes punched in it for windows, This tube was designed to be a Vierendeel truss to resist the lateral wind loading.
Just as the exterior tube was designed as a Vierendeel truss to resist horizontal wind loading, it acted like a Vierendeel truss to span norizontally and carry the floor loading across the holes in the outer wall created by the aircraft.
(Christopher M Foley (assistant Professor of Civil Engineering ( Marquette University)
<br>http://www.marquette.edu/engineering/pages...ASTERAR2001.pdf
QUOTE (-> | QUOTE | Therefore, the exterior tube of the building was essentially a solid piece of steel with holes punched in it for windows, This tube was designed to be a Vierendeel truss to resist the lateral wind loading.
Just as the exterior tube was designed as a Vierendeel truss to resist horizontal wind loading, it acted like a Vierendeel truss to span norizontally and carry the floor loading across the holes in the outer wall created by the aircraft.
(Christopher M Foley (assistant Professor of Civil Engineering ( Marquette University)
<br>http://www.marquette.edu/engineering/pages...ASTERAR2001.pdf
...on 9-11, when the exterior columns were pierced, they were able to redistribute the weight and create what is called a Vierendeel truss around the hole blown in the building.
<br>http://www.uvm.edu/~uvmpr/vq/vqspring04/lipton.html
| QUOTE | Most of the load redistributed due to aircraft impact occured on the external face through vierendeel action.
<br>Page 5 - http://wtc.nist.gov/progress_report_june04/appendixq.pdf.
QUOTE (-> | QUOTE | Most of the load redistributed due to aircraft impact occured on the external face through vierendeel action.
<br>Page 5 - http://wtc.nist.gov/progress_report_june04/appendixq.pdf.
The moment resisting framing above the damage provided an alternate path for gravity loads.
<br>http://mceer.buffalo.edu/publications/resa...rmanandWarn.pdf.
| QUOTE | The perimeter frame then redistributed the loads carried by the buckled columns to adjacent columns by Vierendeel action.
<br>http://132.236.67.210/engrc350/EngrWords/i...vensonC_PR2.pdf.
QUOTE (-> | QUOTE | The perimeter frame then redistributed the loads carried by the buckled columns to adjacent columns by Vierendeel action.
<br>http://132.236.67.210/engrc350/EngrWords/i...vensonC_PR2.pdf.
Analyses of the global models of the towers indicated that when columns are severed in the exterior walls, the walls can redistribute their load through the vierendeel action of the wall above the severed columns.
<br>Nist (Draft) Final Report
Now, Schneibster... am I lying again? Are NIST and these other engineers lying, or would you care to retract your erroneous assumption?
Just as a footnote, here is another erroneous statement made with airs of authority ... which is WRONG...(speaking of the towers construction)
| QUOTE | posted by Schneibster
This non-traditional design has not been widely copied.
<br>Malarky !!! Who do you think you are fooling ? Since the towers went up virtually all (the majority of) superstructures have copied the essential design originated by Yamasaki et al. Here is what Bill Manning stated in 2002...
QUOTE (-> | QUOTE | posted by Schneibster
This non-traditional design has not been widely copied.
<br>Malarky !!! Who do you think you are fooling ? Since the towers went up virtually all (the majority of) superstructures have copied the essential design originated by Yamasaki et al. Here is what Bill Manning stated in 2002...
Such destruction of evidence shows the astounding ignorance of government officials to the value of a thorough, scientific investigation of the largest fire-induced collapse in world history. I have combed through our national standard for fire investigation, NFPA 921, but nowhere in it does one find an exemption allowing the destruction of evidence for buildings over 10 stories tall.
Hoping beyond hope, I have called experts to ask if the towers were the only high-rise buildings in America of lightweight, center-core construction. No such luck. I made other calls asking if these were the only buildings in America with light-density, sprayed-on fireproofing. Again, no luck- they were two of thousands that fit the description. (emphasis mine)
http://fe.pennnet.com/Articles/Article_Dis...7&VERSION_NUM=1
Foxx
2nd December 2005 - 10:53 PM
Whoops, went to edit the previous post and somehow ended up reposting the same here, which is now deleted.
Schneibster
2nd December 2005 - 11:16 PM
QUOTE (adoucette+Dec 2 2005, 10:10 PM) You know how you can tell that your posts are hurting their conspiracy theories?
They call you a shill.
Arthur Yep, and they get nasty and tell you you need psychological help, too. Never fails. IIRC that's called "projection."
Schneibster
2nd December 2005 - 11:44 PM
QUOTE (metamars+) the extraordinary speed of the collapses (12 - 16 seconds vs. free fall in vacuum speeds of about 8-9 seconds) |
Actually, it appears that somewhat less than 8 seconds would be free-fall time from the point of collapse for 2 WTC; I guesstimate most of 9 seconds for 1 WTC, probably just under it, but we'll see when I substitute the stories above and height of the collapse point into the program. We also showed with BOTH our programs that accelerating the floor slabs (no matter how much force it requires- remember, the momentum WILL be conserved as long as the force is great enough to keep the debris falling) took only an extra second or so for 2 WTC. I think after looking our results over that the big question isn't "why did they fall so fast" but "why did they fall so slow." I think I'm preaching to the choir here- from what you've posted since we posted our results, I think you already know this. But it's worth noting nevertheless. QUOTE (metamars+) and their symmetry. |
I'm not sure where you stand on this currently. I think that the point has been made (by RealityCheck, IIRC) that the perimeter columns would have provided at least some containment of the falling material. I'd also like to point out that the debris footprint seems to be quite large; the debris fields for each building spread around the buildings to farther from the original outsides of their perimeters than the buildings are wide. Someone else somewhere or other also pointed out that buildings are designed so they don't fall into other buildings; the WTC towers seem to have performed remarkably badly in this respect, damaging 5 and 6 so badly they had to be torn down afterward, causing the collapse of 7, and seriously damaging the Banker's Trust building; I believe there were other large buildings nearby that were damaged as well. I'm not sure how much symmetry that implies. IMO, not much. QUOTE (metamars+) (IMO, the symmetry of the collapse of WTC 7 is so perfect it's not even worth arguing about. Thus, questions about symmetry of collapses should start with videos of WTC 7, not WTC 1 or 2.) |
Hmmmm. Well, given that the East penthouse seems to disappear first, and the West penthouse afterward, and that the windows at the top of 7 WTC only showed sky after their respective penthouses had collapsed, I'm not sure this isn't more a matter of the OUTSIDE of the building collapsing relatively symmetrically rather than the INSIDE. In fact, the line of window breakages and the "kink" in the top in front of where the East penthouse was before it disappeared argue that it was not nearly as symmetric as your statement here implies. It looks to me from the video evidence like the East interior collapsed first, then the West interior followed it, and the exterior fell when there was no longer anything inside to support it. What's your view? QUOTE (metamars+) I seriously doubt that there has been any extensive study of how a collapse could possibly proceed symetrically and with such and such a speed. |
Actually, I believe that FEMA has released the results of numerical simulations that purport to study exactly that- at least, they model the collapses. How symmetrical they are I cannot say. QUOTE (metamars+) The architect insisted that the building performed very well. |
I agree, and I'm not surprised. QUOTE (metamars+) I'D ALSO RECOMMEND ASKING AT LEAST SOME OF THE CONSTRUCTION ENGINEERS "HOW CAN THE TOP OF THE SOUTH TOWER TILT BY APPROXIMATELY 25 DEGREES, THUS ACQUIRING ANGULAR MOMENTUM, AND THE THE ROATION BASICALLY JUST CEASE? |
I believe that the observations I made in the first or second collapse video from 9/11 Research were that it in fact never did stop rotating; it was destroyed before it could get to more than about 30 degrees. Take another look. I'll dig up the link if you like. Let me know.
Schneibster
2nd December 2005 - 11:49 PM
RealityCheck, I've finished thinking about the effects of the perimeter columns after the hat truss stopped holding them up. It seems to me that in the "core collapse first" scenario, when the hat truss and the top of the building in 1 WTC started down, any impulse that the perimeter columns had to impart would have happened in the first second or so; after that, they would be taller overall than the core or floor slabs, so their effect would have been a lot more likely to be to hold up the floor slabs than to pull them down. But I see reason to believe that it would have given one big yank in that first second, and that might have weakened a lot of things down the building. I'm not sure, unfortunately, how to quantify that; we'd have to have details about how much force the hat truss was exerting on the core columns or how much a single perimeter column weighed to quantify that. I still think this was good thinking.
frater plecticus
3rd December 2005 - 12:34 AM
9:11 AN ABSOLUTE ACT IN A RELATIVE WORLD: The most revealing comment in the previous 80 pages is the following: Guest Posted on Dec 2 2005, 05:27 PM Page 80 QUOTE Its appears easy to get mixed up in the minutae of the physics but the reality is staring anyone who takes the time to examine the evidence straight in the face - not only is the official tale absurd it is that mind blowingly so I can only imagine that in pre internet times such slapstick ventures would not have been so easily exposed. <br>Like I mentioned nearly 80 pages back... My First class Degree Dissertation in Communication Design (spring 1999) QUOTE (-> | QUOTE | Its appears easy to get mixed up in the minutae of the physics but the reality is staring anyone who takes the time to examine the evidence straight in the face - not only is the official tale absurd it is that mind blowingly so I can only imagine that in pre internet times such slapstick ventures would not have been so easily exposed.
<br>Like I mentioned nearly 80 pages back...
My First class Degree Dissertation in Communication Design (spring 1999)
Virtually every (apparently) important event in recent times has been recorded, edited, digitally remastered and recontextualised within the televisual environment. These have ranged from man's first step on the moon to the death of Princess Diana to the crumbling of the Berlin Wall, many of which have been broadcast live to audiences of billions.
'This sense of immediacy and truthfulness which is the result of watching a steady stream of images interpreted with authority is what George Gerbner warned about as'instant history' - that is, history constructed by technology which 'concentrates power, shrinks time, and speeds action to the point where reporting, making and writing history merge'
<a href='http://plectic.com/diss.pdf' target='_blank' rel='nofollow'>http://plectic.com/diss.pdf
Occult aspects of war.
Julius Evola seems to differentiate between views of history using dimensional metaphors.
| QUOTE | The concept of occult war must be defined within the context of the di-lemma. The occult war is a battle that is waged imperceptibly by the forces of global subversion, with means and in circumstances ignored by current historiography. The notion of occult war belongs to a three-dimensional view of history: this view does not regard as essential the two superficial I dimensions of time and space (which include causes, facts, and vis of warible leaders) but rather emphasizes the dimension of depth, or the "subterranean" dimension in which forces and influences often act in a decisive manner, and which, more often not than not, cannot be reduced to what is merely human, whether at an individual or a collective level.
<!--QuoteBegin-->QUOTE (-> | QUOTE | The concept of occult war must be defined within the context of the di-lemma. The occult war is a battle that is waged imperceptibly by the forces of global subversion, with means and in circumstances ignored by current historiography. The notion of occult war belongs to a three-dimensional view of history: this view does not regard as essential the two superficial I dimensions of time and space (which include causes, facts, and vis of warible leaders) but rather emphasizes the dimension of depth, or the "subterranean" dimension in which forces and influences often act in a decisive manner, and which, more often not than not, cannot be reduced to what is merely human, whether at an individual or a collective level.
<!--QuoteBegin)Often the tactic of replacement develops efficaciously in the form of a tactic of counterfeits. It may happen that after the effects of the destructive work reach the material plane, they become so visible as to provoke a reaction, and thus ideas and symbols are employed for a defense and a reconstruction. In the best scenario they are values of the traditional past, which come back to life thanks to this existential reaction of a society or civilization threatened by dissolution. Then the occult war is not waged in a direct manner; often attention is paid to promoting only distortions and counterfeits of these ideas. In this way, the reaction is contained, deviated, or even led in the opposite direction. Cue Korans and passports...
| QUOTE | Finally, I wish to mention one more instrument of the secret war, though it refers to a very particular domain: the tactic of the replacing infiltrations. It is when a certain spiritual or traditional organization falls into such a state of degeneration that its representatives know very little of its true, inner foundation, or the basis of its authority and prestige. The life of such an organization may then be compared to the automatic state of a sleepwalker, or living body deprived of its soul. In a sense a spiritual "void" has been created that can be filled, through infiltrations, by other subversive forces. These forces, while leaving the appearances unchanged, use the organization for totally different purposes, which at times may even be the opposite of those that were originally its own. We should also not rule out the case where such infiltrated elements work for the destruction of the organization that they now control—for ex-ample, by creating new scandals, liable to give rise to serious repercussions.
<a href='http://www.indymedia.org.uk/en/2005/11/327220.html' target='_blank' rel='nofollow'>http://www.indymedia.org.uk/en/2005/11/327220.html
The American body politic is unraveling in real time. The historical fraud perpetuated on 9-11, did not account for new media (decentralized technologies). The litmus test was the 7th July 2005 bombings in London, as noted in the London Guardian, "Seasoned news executives talk of a "tipping point", a democratization of the news process, the true birth of the "citizen reporter". The public assuming control of the news gathering process to a hitherto unimagined degree." The article continues.."Minutes after the bombings occurred in London last Thursday, newsrooms around the capital were being deluged with pictures and video clips sent directly from the scene. " The instantaneous inconsistencies in the official story have been documented.
The revelations about the USA government to "control the context" is oxymoronic to say the least. What are these assholes going to do next, cut all the "subversive" information agents´Internet lines? Internet in inherently Democratic in nature, that´s why when Tony Blair cuts and pastes´somebody´s old thesis to KNOWINGLY FABRICATE EVIDENCE, he´s gonna get found out, because it´s all gone REAL TIME.
QUOTE (-> | QUOTE | Finally, I wish to mention one more instrument of the secret war, though it refers to a very particular domain: the tactic of the replacing infiltrations. It is when a certain spiritual or traditional organization falls into such a state of degeneration that its representatives know very little of its true, inner foundation, or the basis of its authority and prestige. The life of such an organization may then be compared to the automatic state of a sleepwalker, or living body deprived of its soul. In a sense a spiritual "void" has been created that can be filled, through infiltrations, by other subversive forces. These forces, while leaving the appearances unchanged, use the organization for totally different purposes, which at times may even be the opposite of those that were originally its own. We should also not rule out the case where such infiltrated elements work for the destruction of the organization that they now control—for ex-ample, by creating new scandals, liable to give rise to serious repercussions.
<a href='http://www.indymedia.org.uk/en/2005/11/327220.html' target='_blank' rel='nofollow'>http://www.indymedia.org.uk/en/2005/11/327220.html
The American body politic is unraveling in real time. The historical fraud perpetuated on 9-11, did not account for new media (decentralized technologies). The litmus test was the 7th July 2005 bombings in London, as noted in the London Guardian, "Seasoned news executives talk of a "tipping point", a democratization of the news process, the true birth of the "citizen reporter". The public assuming control of the news gathering process to a hitherto unimagined degree." The article continues.."Minutes after the bombings occurred in London last Thursday, newsrooms around the capital were being deluged with pictures and video clips sent directly from the scene. " The instantaneous inconsistencies in the official story have been documented.
The revelations about the USA government to "control the context" is oxymoronic to say the least. What are these assholes going to do next, cut all the "subversive" information agents´Internet lines? Internet in inherently Democratic in nature, that´s why when Tony Blair cuts and pastes´somebody´s old thesis to KNOWINGLY FABRICATE EVIDENCE, he´s gonna get found out, because it´s all gone REAL TIME.
Government officials loyal to "a private network of operatives who have penetrated the government who are not loyal to the Constitutional chain of command but in fact to the orders that are coming from some command center outside."
<br>Adoucette, or Arthur or Arthur Doucette
Threads started by Arthur.
http://www.airdisaster.com/forums/search.p...61&pp=25&page=1
FAA, NORAD and 9/11.
http://www.airdisaster.com/forums/showthread.php?t=53044
Notes on radiation, by Arthur Doucette June, 2001.
http://64.233.183.104/search?q=cache:SE4O5...Arthur+Doucette
Climate debate maestro.
http://64.233.183.104/search?q=cache:7bOOQ...Arthur+Doucette
Flight crash expert.
http://64.233.183.104/search?q=cache:bij5n...Arthur+Doucette
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About Carreker-Antinori - Carreker-Antinori, Inc. is a leading provider of integrated consulting and software solutions that enable banks to increase revenue and/or reduce costs, while leveraging institutions’ existing core competencies in order to realize their e-commerce potential. The Company's offerings include revenue enhancement, payment systems, and e-business solutions. The Company's customers include 170 financial institutions in the U.S., Canada, United Kingdom, Ireland and Australia, including 70 of the largest 100 banks in the United States.
http://64.233.183.104/search?q=cache:5zSqY...r-Antinori,+Inc
STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP
http://64.233.183.104/search?q=cache:DIDXq...r-Antinori,+Inc
And wadda know, you are also part of this mammoth 10 mb list. (INCIDENTALLY FOUND on the UNITED STATES SECURITIES AND EXCHANGE COMMISSION SERVER. I HAD TO "TRANSLATE IT" TO MAKE IT VISIBLE)
http://translate.google.com/translate?hl=e...%3D%26client%3D
DOUCETTE ARTHUR:0001061807:
ARTHUR, Why is it that IN AUGUST 2002 YOU WERE POSTING DEBATING CONSPIRACIES regarding the 9-11 terrorist attacks, yet in this VERY DEBATE you claim "I'm new to this conspiracy idea that we blew the WTC." ?
3 YEARS SPREADING PROPAGANDA. YOU SHOULD THINK DEEP AND HARD BEFORE YOU REPLY TO THIS.
| QUOTE | It is also used as a shorthand for political dirty tricks, particularly those involving false documents.
http://en.wikipedia.org/wiki/Modified_limited_hangout
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an 18-minute film made in 1983 of the construction of the Twin Towers called "The Center of the World".
http://www.pbs.org/wgbh/amex/newyork/sfeat...pop_01_qry.html
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Osama bin Laden - Evil Supergenius?
Osama bin Laden is an evil supergenius, so we have been told by the Bush administration (but most people now understand that the Bushies lie about everything). Only a supergenius could have come up with such a plan and carried it out, they say.
It's not like there isn't already enough proof to hang these bastards, but the problem is getting some people to accept it.
http://briandeford.blogspot.com/2005/11/os...upergenius.html
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Disturbingly, and further suggestive of a generational sickness, Bush's sexual vulgarity appears to have a parental component. Asked at the Republican Convention in 1988 [the second convention at which Omaha's Larry King - paedophile, pimp, Satanist and Bush confidant - had been invited to sing the national anthem] "When you're not talking politics, what do you and [your father] talk about?" He replied, "Pussy."
http://rigorousintuition.blogspot.com/2005...le-dog-too.html
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<br>QUOTE (-> | QUOTE | It is also used as a shorthand for political dirty tricks, particularly those involving false documents.
http://en.wikipedia.org/wiki/Modified_limited_hangout
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an 18-minute film made in 1983 of the construction of the Twin Towers called "The Center of the World".
http://www.pbs.org/wgbh/amex/newyork/sfeat...pop_01_qry.html
--------------------------------------------------------------------------------------------------------
Osama bin Laden - Evil Supergenius?
Osama bin Laden is an evil supergenius, so we have been told by the Bush administration (but most people now understand that the Bushies lie about everything). Only a supergenius could have come up with such a plan and carried it out, they say.
It's not like there isn't already enough proof to hang these bastards, but the problem is getting some people to accept it.
http://briandeford.blogspot.com/2005/11/os...upergenius.html
--------------------------------------------------------------------------------------------------------
Disturbingly, and further suggestive of a generational sickness, Bush's sexual vulgarity appears to have a parental component. Asked at the Republican Convention in 1988 [the second convention at which Omaha's Larry King - paedophile, pimp, Satanist and Bush confidant - had been invited to sing the national anthem] "When you're not talking politics, what do you and [your father] talk about?" He replied, "Pussy."
http://rigorousintuition.blogspot.com/2005...le-dog-too.html
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<br>
To The Warmongers
I'm back again from Hell
With loathsome thoughts to sell;
Secrets of death to tell;
And horrors from the abyss.
Young faces bleared with blood,
Sucked down into the mud,
You shall hear things like this,
Till the tormented slain
Crawl round and once again,
With limbs that twist awry
Moan out their brutish pain,
As the fighters pass them by.
For you our battles shine
With triumph half-divine;
And the glory of the dead
Kindles in each proud eye.
But a curse is on my head,
That shall not be unsaid,
And the wounds in my heart are red,
For I have watched them die.
Written in 1917 by Siegfried Sassoon, who fought for Britain in World War I:
<br>100 000 DEAD IN IRAQ ARTHUR, IT´S NOT A GAME.
30 000 PEOPLE ARE READING THIS.
Schneibster
3rd December 2005 - 01:36 AM
Thought we were gonna knock the intimidation stuff off, frater. It's costing you cred when you do this. I don't respect it, and I don't respect you when you do it.
RealityCheck
3rd December 2005 - 02:01 AM
QUOTE (Foxx+Dec 2 2005, 10:41 PM) In actual fact, because the loads were redistributed around the impact hole the building (had it not been demo'd) could have stood indefinately with this hole in the wall - until the building was compromised by some other extreme event such as a 140 mph hurricane or relatively large earthquake. No engineers even suggest that this hole was contributory to the 'collapse'. FEMA even provided a diagram which shows how this Vierendeel truss wall redistributed the loads... As indicated, only a small portion of the columns directly above the impact hole were 'hanging' in tension. Because of the Vierendeel action the majority of the loads were redistributed around the hole such that little to no additional loads were placed upon the hat truss directly above the hole. In actual fact, the loads on the building were no greater with this gaping hole in one side than loads imposed under heavy wind loads... . . Hello Foxx. Just browsing through on my way to other forums, and noticed your post on load-redistribution. As is my won't, I always look at the non-obvious aspects of everything (hence my earlier observations). [But before I get to those: I just heard the news that JAMES HARDIE IN AUSTRALIA has signed on the dotted-line for S4 Billion or so to compensate employee ASBESTOS victims. Are you yourself involved in any similar class-action'compensation package' battle over there? Just curious, mate. If you are, then good luck to you!] Regarding the above diagram showing the 'triangular arch' redistributing the loads as you state, it seems to me that at each end of the BASE of that arch, ALL the forces must negotiate THROUGH ONLY THOSE WALL-SEGMENTS LEFT on that face of the tower. So the loads, irrespective of where/what type, would have concentrated all the previous loads into those few remaining segments----again, IRRESPECTIVE of how that load is re-distributed AROUND the 'hole'----and so, not only would the full loads be still active and concentrated JUST on those few end-wall segments WHILE THE RE-DISTRIBUTION is 'active', but the 'missing' wall-segments (previously going 'through' the space where the 'hole' is) would NOT now BALANCE/SPREAD the 'pull' on the HAT TRUSS all along its full-face length. In which case, the ARCH' of the wall above the hole is like the top-members of a 'bridging arch' with its 'legs' sending the weight into the 'feet' at either 'end'. Such 'spreading-pressure' at those 'feet' will naturally tend to 'push apart' that face of the building face at the floor(s) where the load is being re-distributed past the few remaining 'end-wall' segments. This to my mind would tend to stress those connections at the two affected corners, as the 'walls' of the adjacent 'faces' are pushed outward at those corners through which the re-distribution of load is being 'channelled'. All this ignores anything to do with whether the columns/walls were THEMSELVES designed to take the FULL load (or not) of everything connected to them at each level; or whether those walls were (or not) designed to basically hold ONLY THEMSELVES up (ie, with the HAT TRUSS supposed to take any load of floor structure weight, and 'statically' re-transmit that to the core structure...I'm still not clear on that). Anyhow, that's my hit and run observation on the above. I wish I had more time to really get my teeth into this. Still, I'm learning a lot about the nitty-gritty of construction/demolition systems/techniques! Good luck! RealityCheck. PS: SCHNEIBSTER...Thanks for kind words. Just trying to do my best with what I've got left; as I believe everyone else here is too. RC. .
Guest_metamars
3rd December 2005 - 02:08 AM
metamars here, posting from my linux box
| QUOTE | You know how you can tell that your posts are hurting their conspiracy theories?
They call you a shill.
Arthur
<br>Sometimes. However, if you mean to imply that all or most people who refer to others as shills do so because their "conspiracy theories are being hurt", I find that to be a self-serving "observation", which obscures a larger truth. And that is, some people call others shills because no matter how badly their argument is refuted, or how doubtful their "facts" or "reasoning" may be shown to be, they still insist that they are right.
In everyday life one meets many individuals who lack critical thinking skills, so this is, at first glance, unremarkable. However, about the only people that I meet who NEVER change their minds are people who are required to not do so by their religion. I am thinking about fundamentalists in general, and creationists in particular.
Thus, I am a bit suspicious regarding 'popish' posters, though I again say that calling somebody a "shill" when you don't know that to be the case is uncalled for, and frankly, unfair.
I used to have a brilliant cousin who believed in the Oswald-the-lone-assassin government Fairy Tale re the JFK assassination. Unlike me, my cuz had actually READ THE ENTIRE WARREN COMMISSION REPORT.
I asked my cousin the simple question "Who was in charge of getting the evidence that the Warren Commission examined?" HE DIDN'T KNOW.
I knew. It was the FBI, and they did intimidate many witnesses into changing their initial testimony to match the government's official Fairy Tale.
When I told my cousin this, it went in one ear, and out the other. After all, why would the FBI do that?
Thus, having even very informed and brilliant debate opponents who just cannot process certain information is not unknown to me. My cousin was no shill - he just had his own way of dealing with reality. His "axioms" regarding what sources of information are credible and what are not, and what sort of behavior is believably indulged in by various US government employees and what is not, were very different than mine. Different axioms, different theory.
However, even he was not a 'pope', and his mind was more open on other subjects.
If there are real shills "out there" or even "here", my assumption is that their "popishness" is meant to demoralize Truth activists. But that is just a guess, and frankly I don't particularly care if somebody is really a shill or not. I am genetically programmed not to be discouraged by nay-sayers. I am actually happy to have opponents who can and do produce valuable insights, facts, and yes, even reasoning which I can use to discard wrong notions of my own.
Even if some of their "insights", "fact", or "reasoning" are not useful.
The key thing is to filter out the noise from the signal. I can assure everybody that I read the posts of posters on both sides of the debate more carefully (or at all) if they have a history of high signal to noise. I'm not interested in reading anybody's emotional spew - this is certainly noise and not signal.
Anybody who wants insight into how minds can be 'religiously' irrational wrt non-religious beliefs would do well to read the chapter on Religion in E.O.Wilson's "On Human Nature". Don't forget that 911 was not just a black op, it was also a psy-op. Hoffman has written on this aspect of the attacks. Thus, circumventing people's more rational faculties (dubious as they mostly are, even under the best of circumstances ) was pretty easy to do via the horror and inherent "unreality" of the events of 911. And that's without seeing videos of telescoping, powderizing spires (which might have given the game away.)
Time to awaken from our dreams, ladies and gentlemen.
Foxx
3rd December 2005 - 02:09 AM
| QUOTE | posted by Schneibster
It's costing you cred when you do this.
<br>Look who's talking about credibility. Hahaha. Someone who has none whatsoever.
A guy who makes up about stuctural 'facts' of the WTC, as he sees fit.
(The steel columns in the central core were encased in concrete... didn't you know?)
QUOTE (-> | QUOTE | posted by Schneibster
It's costing you cred when you do this.
<br>Look who's talking about credibility. Hahaha. Someone who has none whatsoever.
A guy who makes up about stuctural 'facts' of the WTC, as he sees fit.
(The steel columns in the central core were encased in concrete... didn't you know?)
Originally posted by Schneibster
Remember, this force is being transmitted down a rigid column of concrete with rigid columns of steel inside it; that means that it shatters rather than yielding.
<br>And still promoting the engineering nonsense that the hat truss held up the perimeter columns (even after the nonsense was completely refuted by FEMA, NIST, and a raft of structural engineers)... see my last post.
| QUOTE | I've finished thinking about the effects of the perimeter columns after the hat truss stopped holding them up.
<br>
It is quite clear that he makes up his 'facts' as he goes along.
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