9/11 Physics from Non-Experts [Archive] - Page 5

R.Mackey

10th June 2007, 03:16 PM

Here (http://forums.randi.org/showthread.php?postid=1908886#post1908886) is the post where Mackey says the the cores were cross braced by the floor assemblies.

Ryan, I've asked you directly, and you've never answered.

Did the cores have their own independent flooring systems?

Were the cross braces, as shown in Frank's picture, removed after construction?

Those are both yes/no questions.

Liar, here is your picture:

http://homepage.mac.com/dansound/.Public/Pix/SteelOnFire/WTC_Core_03s.jpg

And here is Dr. Greenings:

http://i207.photobucket.com/albums/bb98/visibility911/wtc4small.jpg

Dr. Greening's picture shows cross bracing low in the core, well away from the impact floors. Your picture shows kangaroo cranes. I have never before today seen Dr. Greening's picture.

What Dr. Greening's picture shows was not removed, ever, and is irrelevant for purposes of collapse initiation.

Back on Ignore you go. It's a pity that even though I haven't had any contact with you whatsoever for months, you still harbor the same monomaniacal idiocy. Seek help, I beg you.

Gravy

10th June 2007, 03:33 PM

The cross bracing in the Greening photo is on the exterior columns, below grade.

R.Mackey

10th June 2007, 03:37 PM

Gravy

10th June 2007, 03:45 PM

The vast overwhelming majority of reports of explosions by news networks on 9/11 refer to either one of the aircraft impacts or one of the building collapses.

Watching the clips in context, this is too often painfully obvious.

The collapses were almost universally described as "huge explosions".

-GumbootActually, only 11% of the over 700 descriptions of the collapses that I've gathered describe them as explosions or like explosions. The conspiracists take that 11% out of context and present it as if it's the majority.

TruthSeeker1234

10th June 2007, 06:06 PM

Thanks for that correction. Like I said, I had never seen that picture before. That fact pretty much guarantees that it isn't what Ace thought he was talking about.

In any event, it clearly has nothing to do with the core in the impact floors.

Originally, we were discussing the "collapses". Not "collapse initiation". I've never been particularly interested in "collapse initiation". I don't think those upper parts would "collapse" under fires and that kind of damage, but I don't care. The interesting part is the part NIST ignored:

How in hell does a collapse cause the building to explode into powder?

You were trying to convince me that the cores were not braced, except by the main floor assemblies. Newton's bit on this very thread has now confirmed that the cores had their own independent flooring (IE CROSS BRACING) system.

You were trying to convince me that the cores were braced only by the main floor assemblies. Newton's bit agrees with me, although I was trying to get a simple yes or no answer out of him. Or you. Or anyone.

Fetzer might be wrong on some points. But he's right about one thing. There is a special place in hell reserved for you guys.

Thunder

10th June 2007, 06:13 PM

If Truthseeker has his way, after the "revolution", all JREFers will be rounded up and sent to a concentration camp for our "crimes".

stateofgrace

10th June 2007, 06:16 PM

There is a special place in hell reserved for you guys.

Including this guy Ace?

Quote:

Originally Posted by jujigatami http://forums.randi.org/helloworld2/buttons/viewpost.gif (http://forums.randi.org/showthread.php?p=2602344#post2602344)
Quote:
Ace, TS, or whatever you call yourself,

Could you please explain to me how the NWO, Government, or whoever you think made these videos also somehow implanted the images of 2 planes hitting the WTC in to my EYEBALLS!

See, I was there, and I personally witnessed both planes hitting the buildings.

I saw everything, EVERYTHING!

I saw it firsthand, not on video, not by description after the fact. I saw BOTH PLANES HIT THE BUILDINGS!!!

Please explain how I saw what you say didn't happen.

Please, this I gotta hear.

Originally Posted by jujigatami http://forums.randi.org/helloworld2/buttons/viewpost.gif (http://forums.randi.org/showthread.php?p=2602711#post2602711)
Quote:
Forget that, he can't be asked to explain what people didn't see. I just want him to explain what I did see.

I was a few hundred yards from WTC1 walking towards it when the first plane hit. I looked up when I heard an incredibly loud jet engine sound a second or two before the plane hit. It was so loud that the ground was vibrating and I actually felt the sound. Of course the crash and resulting explosion was even louder, but I'll never forget the sound of the jet. Its what made me look up. Then there it was, an American Airlines jet flying full speed in to the north tower.

So please tell me Ace, how did the big bad NWO not only implant images in to my eyeball, but also have the accompanying sound effects so perfectly staged?

Whom you have failed to recognise, failed to acknowledge.

I will not respond in kind to your insults, you do not deserve it , you deserve nothing but condemnation and contempt, this you have worked for and this you will receive.

Newtons Bit

10th June 2007, 08:18 PM

Originally, we were discussing the "collapses". Not "collapse initiation". I've never been particularly interested in "collapse initiation". I don't think those upper parts would "collapse" under fires and that kind of damage, but I don't care. The interesting part is the part NIST ignored:

How in hell does a collapse cause the building to explode into powder?

You were trying to convince me that the cores were not braced, except by the main floor assemblies. Newton's bit on this very thread has now confirmed that the cores had their own independent flooring (IE CROSS BRACING) system.

You were trying to convince me that the cores were braced only by the main floor assemblies. Newton's bit agrees with me, although I was trying to get a simple yes or no answer out of him. Or you. Or anyone.

Fetzer might be wrong on some points. But he's right about one thing. There is a special place in hell reserved for you guys.

I completly disagree with you. Now take this statement out of context. The only place in the building that had cross-bracing was on the seven stories and LOWER.

"independent flooring (IE CROSS BRACING) "!?!?? How the hell did you get that from what I said. I said that they were continuous flooring. How is it that a floor slab means cross-bracing? You're not even taking what I said out of context, you're making stuff up. Do not alter your perception of the universe such that I agreed with what you said. Let me restate what it really is IT IS THE SAME FLOORING SYSTEM IT JUST HAS A THICKER STURDIER SLAB. Is that clear enough for you? Go read a freaking book and get a clue.

This is case and point in WHY the truth movement exists. You can't understand anything! Your perception of how it should be morphs what people say into what you think they should be saying. GET HELP!

gumboot

10th June 2007, 08:28 PM

Actually, only 11% of the over 700 descriptions of the collapses that I've gathered describe them as explosions or like explosions. The conspiracists take that 11% out of context and present it as if it's the majority.

Are they all live news broadcast from the day, or post event interviews?

-Gumboot

Slayhamlet

10th June 2007, 09:23 PM

Originally, we were discussing the "collapses". Not "collapse initiation". I've never been particularly interested in "collapse initiation". I don't think those upper parts would "collapse" under fires and that kind of damage, but I don't care. The interesting part is the part NIST ignored:

How in hell does a collapse cause the building to explode into powder?

You were trying to convince me that the cores were not braced, except by the main floor assemblies. Newton's bit on this very thread has now confirmed that the cores had their own independent flooring (IE CROSS BRACING) system.

You were trying to convince me that the cores were braced only by the main floor assemblies. Newton's bit agrees with me, although I was trying to get a simple yes or no answer out of him. Or you. Or anyone.

No he doesn't agree with you. You consistently show a lack of understanding of what those with expertise, whether it be NIST or R. Mackey or Newtons Bit, are trying to explain to you. You consistently take their words out of context and twist them into what you want to hear. You consistently fail to realize that your own silly assumptions do not apply to the real world. Knowing these tendencies of yours, why should any of them feel obliged to even respond to you in the first place?

Fetzer might be wrong on some points. But he's right about one thing. There is a special place in hell reserved for you guys.

And there is a special padded cell in an institution reserved for you, Ace.

You may not have realized it yet, but you are the laughingstock of the "Truth" movement. Nobody takes you seriously. Nobody. Not even your fellow "Truthers". Nuts call you a nut. Other nuts call you a disinfo agent. Why is that, Ace? Why have you so spectacularly failed to convince anyone of your bizarre, outlandish theories? Could it be because they are contradicted by a mountain of evidence? Could it be because you're a simpleton whose pretensions to scientific knowledge and reasoning are an obvious farce?

You are a sad, silly little man who will not stop pretending that his fantasies are worthy of reality's consideration. Please stick to what you're good at: making [rule 8]y musical scores for kiddie-movies.

Corsair 115

10th June 2007, 10:19 PM

How in hell does a collapse cause the building to explode into powder?There was a huge, stories-high pile of debris afterwards. That's hardly powder. The buildings didn't explode either, at least not in the way most folks would think of that term. Besides, where are the distinctive sounds associated with the cutting charges used to demolish building in controlled demolitions? You can't hide those sounds, anyone within blocks can easily distinguish them.

pomeroo

10th June 2007, 10:27 PM

R.Mackey

10th June 2007, 11:34 PM

I completly disagree with you. Now take this statement out of context. The only place in the building that had cross-bracing was on the seven stories and LOWER.

For complete accuracy, that's not quite true. There was also cross bracing on the mechanical and atrium floors, and the hat truss could be considered cross-bracing as well. Remember the two windowless bands approximately 1/3 and 2/3 of the way up the structure? Mechanical floors. Those had cross-bracing in the core as well.

But I've already explained this (with full references) to Ace, he already knows this, he's continued to whine about how I'm "lying" and have a spot reserved for me in Hades or Gehenna or whatever, and the entire board has already had our laughs at him. Months ago. Thread is here (http://forums.randi.org/showthread.php?postid=2273912). Enjoy.

GregoryUrich

11th June 2007, 12:37 AM

For complete accuracy, that's not quite true. There was also cross bracing on the mechanical and atrium floors, and the hat truss could be considered cross-bracing as well. Remember the two windowless bands approximately 1/3 and 2/3 of the way up the structure? Mechanical floors. Those had cross-bracing in the core as well.

But I've already explained this (with full references) to Ace, he already knows this, he's continued to whine about how I'm "lying" and have a spot reserved for me in Hades or Gehenna or whatever, and the entire board has already had our laughs at him. Months ago. Thread is here (http://forums.randi.org/showthread.php?postid=2273912). Enjoy.

I think Truthseeker has a somewhat different vocabulary which contributes to the difficulty of understanding each other. When he says "cross bracing", I believe he means horizontal members (i.e. framed floors), which to my knowledge everyone agrees existed in the core. I believe the "structural" people here think of "cross bracing" as diagonal bracing.

Truthseeker, as one who is constantly debating Mr. Mackey on a number of issues, I have never seen him misrepresent evidence or lie on any occasion

tsig

11th June 2007, 12:42 AM

gumboot

11th June 2007, 04:42 AM

I believe he means horizontal members (i.e. framed floors), which to my knowledge everyone agrees existed in the core.

Although had there not been any floors in the core, it would have made for grand entertainment getting out of the elevator.

Like one of those military officer selection problems...

There's four of you in a lift. You have six planks of wood, two lengths of rope, a 44 gallon drum, and three briefcases. You have fifteen minutes to get from the elevator door to outside the core with all three briefcases. If you slip you (obviously) fall to your death.

-Gumboot

Belz...

11th June 2007, 04:52 AM

There is a special place in hell reserved for you guys.

Liars go to Hell, too, Ace.

I'll be waiting.

Dave Rogers

15th June 2007, 06:12 AM

Bazant's latest paper insists that 80% of the total mass hit the bedrock traveling at approximately 47m/s. That is > 4x10^11 Joules of energy, or 25,000 times the energy for a 2.1 Richter scale quake as measured at the LDEO.

Since you vectored this one into an inappropriate thread, I though it was worth another look. Are you suggesting here that Bazant overestimated the mass by some amount to get this result? If so, let me point out that your mass estimate is of the order of half of Bazant's, which would give something like 12,500 times the seismic energy measured if your analysis is valid. What is your rationale for insisting that 99.996% energy loss is "nonsense" but 99.992% energy loss is entirely reasonable?

Alternatively, if you're suggesting an overestimate of the impact velocity, can you explain how this is consistent with the CD theory, which predicts a higher impact velocity than simple fire-related structural collapse?

If you're trying to make some other point here, could you please clarify what it is?

Dave

GregoryUrich

15th June 2007, 06:36 AM

Since you vectored this one into an inappropriate thread, I though it was worth another look. Are you suggesting here that Bazant overestimated the mass by some amount to get this result? If so, let me point out that your mass estimate is of the order of half of Bazant's, which would give something like 12,500 times the seismic energy measured if your analysis is valid. What is your rationale for insisting that 99.996% energy loss is "nonsense" but 99.992% energy loss is entirely reasonable?

Alternatively, if you're suggesting an overestimate of the impact velocity, can you explain how this is consistent with the CD theory, which predicts a higher impact velocity than simple fire-related structural collapse?

If you're trying to make some other point here, could you please clarify what it is?

Dave

I have never suggested that 99.992% energy loss is reasonable. Please don't put words in my mouth. In fact, I have no idea how efficiently a large compacted mass impacting the bedrock transfers KE to seimic energy. Nonetheless I cannot believe that only 0.004% of KE is transferred.

I am not yet supporting the CD theory but I am critical of Bazant's explanation. The seismic energy issue indicates that Bazant's amount of ejected debris and/or velocity are in error.

I'm not sure how my post is off topic. It is physics. I am not an expert. It is perfectly relevant in regards to that non-experts are capable of pointing out valid issues with physical explanations given by experts.

rwguinn

15th June 2007, 07:08 AM

GregoryUrich

15th June 2007, 07:28 AM

Plkease not the bolded and italicised parts above. See any inconsistency?
You have been informed, time and time again--the Richter scale only indicates peak displacement, which is a measure of peak energy.
The total energy would be a function of the area under the curve, not the peak. But since you're not an expert, your belief overrules all science and logic, right?
If you put a recording ammeter in your electric line, it will show peaks when your air conditioner, or stove, or high power items come on. The total energy you use has little to do with those peaks--you have to get the area under the curve! That occurs over time, not instantaneously

LDEO gave the total seismic energy as 10^7 Joules. Do you have any science or logic that would support your belief?

Dave Rogers

15th June 2007, 07:39 AM

I have never suggested that 99.992% energy loss is reasonable. Please don't put words in my mouth. In fact, I have no idea how efficiently a large compacted mass impacting the bedrock transfers KE to seimic energy. Nonetheless I cannot believe that only 0.004% of KE is transferred.

I'm not trying to put words in your mouth, rather giving you my interpretation for you to dispute, which you have - fair enough. The point I'm making is this: You're describing Bazant's explanation as "nonsense" on the basis that you "cannot believe that only 0.004% of energy is transferred." However, Bazant's calculation relies only on three parameters: mass of the towers, velocity of impact, and percentage impacting the bedrock. You've proposed that the actual mass was only 50% of Bazant's estimate, but that still only leaves 0.008% of the energy transferred. Do you believe that 0.008% energy transfer is reasonable? If not, how do you account for the discrepancy? If you can't account for it, why is Bazant's figure implausible?

I am not yet supporting the CD theory but I am critical of Bazant's explanation. The seismic energy issue indicates that Bazant's amount of ejected debris and/or velocity are in error.

OK, but you have more than four orders of magnitude to account for. Adjusting the amount of ejected debris and the velocity within physically reasonable limits will make very little difference. Let's pick some numbers - suppose 80% of debris were ejected, and the velocity was only 25m/s, meaning that the collapse must have taken longer than Bazant suggests, and the mass is half what Bazant suggests. We're now looking at about 0.06% energy transfer. Have we got to your threshold of belief yet? If not, how much energy should be transferred, and how are you going to reduce the impact energy any more? Before long the towers will be made of balsa wood and taking three hours to fall.

I'm not sure how my post is off topic. It is physics. I am not an expert. It is perfectly relevant in regards to that non-experts are capable of pointing out valid issues with physical explanations given by experts.

The trouble is, what you're doing is what I think of as the single-sided inequality. You say, "The energy transfer is too low." Your opponent says, "If it's too low, how high should it be?" You reply, "I have no idea, but it's still too low." If you have "no idea" what it should be, how do you know it's too low? It doesn't help your credibility, especially when you then present this as an example of an obvious flaw in someone else's argument. In other words, you're not pointing out a valid issue, you're simply presenting an argument from incredulity.

Dave

GregoryUrich

15th June 2007, 08:17 AM

I'm not trying to put words in your mouth, rather giving you my interpretation for you to dispute, which you have - fair enough. The point I'm making is this: You're describing Bazant's explanation as "nonsense" on the basis that you "cannot believe that only 0.004% of energy is transferred." However, Bazant's calculation relies only on three parameters: mass of the towers, velocity of impact, and percentage impacting the bedrock. You've proposed that the actual mass was only 50% of Bazant's estimate, but that still only leaves 0.008% of the energy transferred. Do you believe that 0.008% energy transfer is reasonable? If not, how do you account for the discrepancy? If you can't account for it, why is Bazant's figure implausible?

OK, but you have more than four orders of magnitude to account for. Adjusting the amount of ejected debris and the velocity within physically reasonable limits will make very little difference. Let's pick some numbers - suppose 80% of debris were ejected, and the velocity was only 25m/s, meaning that the collapse must have taken longer than Bazant suggests, and the mass is half what Bazant suggests. We're now looking at about 0.06% energy transfer. Have we got to your threshold of belief yet? If not, how much energy should be transferred, and how are you going to reduce the impact energy any more? Before long the towers will be made of balsa wood and taking three hours to fall.

The trouble is, what you're doing is what I think of as the single-sided inequality. You say, "The energy transfer is too low." Your opponent says, "If it's too low, how high should it be?" You reply, "I have no idea, but it's still too low." If you have "no idea" what it should be, how do you know it's too low? It doesn't help your credibility, especially when you then present this as an example of an obvious flaw in someone else's argument. In other words, you're not pointing out a valid issue, you're simply presenting an argument from incredulity.

Dave

Neither I nor anyone else is saying how high it should be but the four orders of magnitude are not supported in any way by Bazant. So instead of "nonsense" I should have said it is an unsupported claim. You must admit 4 orders of magnitude begs the question. I'll look into seismic energy related to impact events.

I need to be careful using the word believe. I speak Swedish most of the time, and in Swedish it is the same word. I think.

Dave Rogers

15th June 2007, 08:43 AM

Neither I nor anyone else is saying how high it should be but the four orders of magnitude are not supported in any way by Bazant. So instead of "nonsense" I should have said it is an unsupported claim. You must admit 4 orders of magnitude begs the question. I'll look into seismic energy related to impact events.

As far as I can see, it's your assertion that his numbers are inconsistent with the seismic data. So let's look at what Bazant is actually saying. He's calculating a kinetic energy from a mass and a velocity. If you're suggesting that his kinetic energy is incorrect by orders of magnitude, that implies a suggestion that either his mass, his velocity or both are incorrect by orders of magnitude. Where are these orders of magnitude coming from? Even you only claim that his mass is out by about a factor of two. The velocity can't be out by any more than that; note that the impact velocity is the maximum velocity experienced by the falling mass, so an impact velocity of half Bazant's value would mean the minimum possible collapse time would be over 20 seconds.

Do you see my point here? It's that, whatever the seismic data says, Bazant's result simply cannot be as far wrong as you suggest, whatever parameters you want to dispute. So, from a calculation based on a science which by your own admission you have "no idea" about, you're describing Bazant's work as nonsense. This is nothing more than mud-slinging, whatever your first language may be.

Dave

Furcifer

15th June 2007, 02:54 PM

Yah, I'm not sure what, if any, conclusions can be drawn from the seismic data. I ran it by the crew over a PhysOrg a coupla weeks ago and there wasn't much of a reception to it. I thought the readings were more accurate, but it would appear otherwise. It was after all a relatively small seismic event.

GregoryUrich

15th June 2007, 04:35 PM

As far as I can see, it's your assertion that his numbers are inconsistent with the seismic data. So let's look at what Bazant is actually saying. He's calculating a kinetic energy from a mass and a velocity. If you're suggesting that his kinetic energy is incorrect by orders of magnitude, that implies a suggestion that either his mass, his velocity or both are incorrect by orders of magnitude. Where are these orders of magnitude coming from? Even you only claim that his mass is out by about a factor of two. The velocity can't be out by any more than that; note that the impact velocity is the maximum velocity experienced by the falling mass, so an impact velocity of half Bazant's value would mean the minimum possible collapse time would be over 20 seconds.

Do you see my point here? It's that, whatever the seismic data says, Bazant's result simply cannot be as far wrong as you suggest, whatever parameters you want to dispute. So, from a calculation based on a science which by your own admission you have "no idea" about, you're describing Bazant's work as nonsense. This is nothing more than mud-slinging, whatever your first language may be.

Dave

You're right, I shouldn't have called it nonsense on this issue yet. I take that back. I won't call it nonsense again on this issue until I have references to back it up.

Nonetheless, The Great Bazant's erroneous assumption that "crush up" does not begin until "crush down" is complete is in fact nonsense. Neither basic physics nor video evidence support it.

rwguinn

15th June 2007, 04:43 PM

You're right, I shouldn't have called it nonsense on this issue yet. I take that back. I won't call it nonsense again on this issue until I have references to back it up.

Nonetheless, The Great Bazant's erroneous assumption that "crush up" does not begin until "crush down" is complete is in fact nonsense. Neither basic physics nor video evidence support it.

Anybody see what happened to those goalposts?
I swear, they were right there (http://forums.randi.org/showthread.php?postid=2692885#post2692885), just before GregoryUrich posted the above....

Furcifer

15th June 2007, 04:44 PM

Nonetheless, The Great Bazant's erroneous assumption that "crush up" does not begin until "crush down" is complete is in fact nonsense. Neither basic physics nor video evidence support it.

No, it's an acceptable simplification to allow calculation. He acknowledges it in the Bazant/Verdure paper.

Minadin

15th June 2007, 04:58 PM

You were trying to convince me that the cores were not braced, except by the main floor assemblies. Newton's bit on this very thread has now confirmed that the cores had their own independent flooring (IE CROSS BRACING) system.

You were trying to convince me that the cores were braced only by the main floor assemblies. Newton's bit agrees with me, although I was trying to get a simple yes or no answer out of him. Or you. Or anyone.
Let's try to make sure we're all using the same terms to convey the same ideas:

Cross Bracing:
________________
|X|X|X|X|X|X|X|X|
|X|X|X|X|X|X|X|X|

Note: not all bays need to be cross braced in all instances. It might only be used in the outside bays, or a couple of the inside bays, depending on the design.

Diagonal Bracing:
_______________
|/|/|/|/|\|\|\|\|\|
|/|/|/|/|\|\|\|\|\|

Note: not all bays need to be diagonally braced in all instances. It might only be used in the outside bays, or a couple of the inside bays, depending on the design.

No Bracing:
______________
| | | | | | | | | |
| | | | | | | | | |

Newtons Bit

15th June 2007, 06:26 PM

To clarify Minadin, those are elevation views. Or for layman, the side of the building. (And don't forget chevron bracing, though I don't think WTC1&2 had those).

Flooring, does not constitute cross bracing. It laterally braces the columns against buckling (and the beams against bending forms of buckling), but that's it. It does not carry horizontal loads down to the foundation.

GregoryUrich

16th June 2007, 10:03 AM

No, it's an acceptable simplification to allow calculation. He acknowledges it in the Bazant/Verdure paper.

It's not acceptable because it completely changes the dynamics of the situation. "Crush up" first, the most extreme alternative, results in the arrest of collapse. At the end of crush up, there is only one floors colliding with the rubble sitting on the top floor of the lower part.

What actually happened was probably something in between, but with significant effects on collapse time.

rwguinn

16th June 2007, 10:09 AM

It's not acceptable because it completely changes the dynamics of the situation. "Crush up" first, the most extreme alternative, results in the arrest of collapse. At the end of crush up, there is only one floors colliding with the rubble sitting on the top floor of the lower part.

What actually happened was probably something in between, but with significant effects on collapse time.

.... It is physics. I am not an expert. It is perfectly relevant in regards to that non-experts are capable of pointing out valid issues with physical explanations given by experts.

So you are not an expert, but can state with absolute confidence that someone who has studied the subject for years, teaches the subject, and is an expert is 100% wrong.

[ twilight zone theme] woo woo wooo woo [/twilight zone theme]

GregoryUrich

16th June 2007, 12:01 PM

So you are not an expert, but can state with absolute confidence that someone who has studied the subject for years, teaches the subject, and is an expert is 100% wrong.

[ twilight zone theme] woo woo wooo woo [/twilight zone theme]

Very typical of the closed minded to attack with ridicule when they have no substantial argument.

beachnut

16th June 2007, 02:13 PM

Very typical of the closed minded to attack with ridicule when they have no substantial argument.
Even more typical of the challenge minded who have no arguments, no conclusions to just make up stuff and talk. Are you ready yet to expose your great evidence to prove something about 9/11?

What do you think about the topic of the thread, does that physics expert make sense to you?

Furcifer

16th June 2007, 04:28 PM

It's not acceptable because it completely changes the dynamics of the situation. "Crush up" first, the most extreme alternative, results in the arrest of collapse. At the end of crush up, there is only one floors colliding with the rubble sitting on the top floor of the lower part.

What actually happened was probably something in between, but with significant effects on collapse time.

Don't get me wrong, I'm not particularly fond of it, but it is acceptable. Don't forget Greg these are mathematical approximation of a chaotic event, nothing will ever be totally encompassing. Even with an undergrad, I can sit here all day a nit pick at what is not there. If you're going to make these accusations of Bazant, you're gonna need some proof. I don't think that incorporating "crush up" during the collapse will arrest the collapse. If you're going to arrest the collapse you need to find and define equilibrium for the system. Use what ever numbers you've got and give us a figure at least, but don't try to attack Bazant like this, it makes you look bad. The burden of proof in this forum is way higher (trust me I learned the hard way)

pomeroo

16th June 2007, 05:18 PM

Kent1

16th June 2007, 09:14 PM

Yes, I don't agree with everything in the paper. In fact there are some out right errors within the papers research. But I would suggest a discussion with some of the writers.

And yes, I have mentioned your research regarding the towers weight but I don't think your going to get very far on the seismic data.

Scott

GregoryUrich

17th June 2007, 05:17 AM

Even more typical of the challenge minded who have no arguments, no conclusions to just make up stuff and talk. Are you ready yet to expose your great evidence to prove something about 9/11?

What do you think about the topic of the thread, does that physics expert make sense to you?

More of the same Beachnut!

I have already demonstrated a number of issues regarding the weight of the tower which is my focus right now.

1. The statistically predicted average (in-service) superimposed live load is 25% of the design live load. I have given references including NIST and no one seems to be challenging this any more and at least Mackey has accepted this. This is the single largest issue regarding weight. Read my references which I have posted previously.

I think it is very telling that none of the critics here have pointed out one issue that reduces the weight. Here are a couple I have become aware of during the time I have been discussing this here:

2. There is no floor outside the core on floors 3-6, 8, 42, and 76, and there is only a partial floor on the mezzanine (floor 2). Sources are NIST and photos from within the lobby area. Hard to contest.

3. The amount of empty space in the core is on average 28%. The average amount of floor space in the core without a permanent live load is 14%. These are calculated from the architectural drawings. So it's easy to check for anyone who doesn't believe it.

4. Floor support in the sublevels amounted to 6000 tons of steel which I have distributed throughout the building in my initial article. This further reduces P.E.

5. Most really heavy machinery (e.g. cooling, emergency power generation, steem generation was outside the footprint of the building). Again the architectural drawings--hard to argue with.

Together, 1-3 account for approximately 200,000 tons which is very close to the difference between my weight 279,000 tons and the official weight 500,000 tons.

A number of important issues have been pointed out here, which I really appreciate:

1. My SDLs in the core and on mechanical levels are not correct.

2. My variation of steel is incorrect due to the fact that floor support (i.e. trusses) should not be scaled. Nonetheless, Since Bazant uses linear scaling from the base to floor 81 it does support my linear scaling. Actually, since i used linear scaling above the 81st floor I actually put more weight higher in the building which is in favor of gravity driven collapse.

Other issues I was aware of before I started discussing this here (as I have previously pointed out):

1. I have ignored the hat truss and antenna.

2. I have assumed the mechanical level to be the same as all other levels.

I have been forthcoming regarding my methods and sources. I have accepted criticism when that criticism is backed up by evidence or good arguments. Your accusation of "no arguments" and "making stuff up" are nothing but mudslinging.

My article was being discussed here and I joined the discussion. I couldn't care less about your object of ridicule. Do you really get any satisfaction just hammering away at people who are obviously inept?

GregoryUrich

17th June 2007, 05:25 AM

I could sell a bridge to anyone who swallows this one.
Tell us when you conclude that a gigantic, mathematically-impossible conspiracy blew up the buildings. We promise to act surprised.

You are suggesting that I couldn't stand up for my secret CD conclusion? You don't know me and your accusation is offensive.

If I do eventually conclude that a gravity driven collapse was unlikely, I'll definitely let you know.

pomeroo

17th June 2007, 05:59 AM

You are suggesting that I couldn't stand up for my secret CD conclusion? You don't know me and your accusation is offensive.

If I do eventually conclude that a gravity driven collapse was unlikely, I'll definitely let you know.

You disingenuously claimed that you were not a twoofer. It is clear that you will be informing us that a gigantic, mathematically-impossible conspiracy blew up the buildings. You will not explain what EVERY demolition expert in the world gets wrong. Your attitude is highly offensive.

GregoryUrich

17th June 2007, 09:57 AM

You disingenuously claimed that you were not a twoofer. It is clear that you will be informing us that a gigantic, mathematically-impossible conspiracy blew up the buildings. You will not explain what EVERY demolition expert in the world gets wrong. Your attitude is highly offensive.

For you there is only twoofers, liars, and people who agree with you. I am neither a twoofer, a non-twoofer, a liar, or a closed minded JREF nit-pick.

Are you upset about my sarcastic post regarding "arguments not to use against twoofers"? I said I had become a non-truther (i.e. against the truth). It's called irony.

Any opinion or fact that doesn't agree with your "spoon fed by the Kean commission" bedtime story is for you offensive. Not much I can do about that.

It's time for you to prove your claim of mathematical impossibility.

WildCat

17th June 2007, 10:14 AM

Any opinion or fact that doesn't agree with your "spoon fed by the Kean commission" bedtime story is for you offensive. Not much I can do about that.
Troofers always rail on about the 9/11 Commission report, yet whan asked none seems to be able to find a significant error in it. Can you point one out an error in the "Kean Commission" report you dismiss so readily?

pomeroo

17th June 2007, 11:13 AM

For you there is only twoofers, liars, and people who agree with you. I am neither a twoofer, a non-twoofer, a liar, or a closed minded JREF nit-pick.

You are a disingenuous twoofer.

Are you upset about my sarcastic post regarding "arguments not to use against twoofers"? I said I had become a non-truther (i.e. against the truth). It's called irony.

If you're referring to your ham-fisted efforts to disguise your beliefs, it's called bad acting.

Any opinion or fact that doesn't agree with your "spoon fed by the Kean commission" bedtime story is for you offensive. Not much I can do about that.

Stop pretending that you have any interest in what really happened on 9/11/01.

It's time for you to prove your claim of mathematical impossibility.

Yeah, I suppose it is: it's been over a week since the last time I proved it.

Ahem. Let's take an ordinary human who has a fifty-percent chance of revealing a secret. Pair him with another ordinary human and the chance the secret gets out rises to seventy-five percent. But that won't do.

For our gigantic conspiracy, we will employ only G. Gordon Liddy/James Bond types. You'd have to pull out their fingernails to make these guys spill the beans. We'll assign each one a probability of .9 of keeping the secret. Now, take a hundred such characters and--oops! The secret gets out 99.997 % of the time. Hmmm, that won't do either. We'll raise our super-agents' ability to keep their dark secret to .95, and now the truth is revealed only 99.4% of the time.

This isn't going well for the fantasy side. I know: we'll make them all demigods and boost their ability to keep a secret to .97! We'll overlook the fact that finding these extraordinary specimens might prove tricky. This truly special group will let the cat out of the bag a mere 95.2% of the time.

But right at this juncture, when your prospects of being taken seriously have skyrocketed to almost five percent, an inconvenient problem arises. Your imaginary conspiracy does not consist of a hundred evildoers. It must number in the thousands. The list has been posted many times, and will not be repeated here in full, but this invisible army has to, just for starters, cow into silence all the Democrats in the military (we will assume that EVERY Republican in the military is eager to sign off on mass murder), the FAA, the air traffic controllers, all the researchers at NIST, FEMA, the members of ASCE, the forensic examiners, the fire and police departments of NYC and Washington, D.C., the seismologists at the Lamont-Doherty labs, the editors who printed the passenger manifests, the Boeing Corporation--this list gets m-u-c-h longer.

But we'll reduce the number of people complicit in this heinous crime to an implausibly low estimate of five hundred. We'll also raise their probability of keeping mum to an absurd .99. Guess what? The secret gets out 99.3% of the time.

And in almost six years ABSOLUTELY NO ONE has talked.

Sure, that could happen. Thousands of ordinary people would have no motive to blow the whistle on a mass murder of their compatriots. The gigantic invisible army (who funds it, incidentally?) intimidates, well, everyone.

I call it, The Impossibly Vast Conspiracy.

Apollo20

17th June 2007, 11:23 AM

A mistake in the Kean Report?

How about page 305. "At 9:58:59, the South Tower collapsed in ten seconds..."

GregoryUrich

17th June 2007, 02:19 PM

Yeah, I suppose it is: it's been over a week since the last time I proved it.

Ahem. Let's take an ordinary human who has a fifty-percent chance of revealing a secret. Pair him with another ordinary human and the chance the secret gets out rises to seventy-five percent. But that won't do.

For our gigantic conspiracy, we will employ only G. Gordon Liddy/James Bond types. You'd have to pull out their fingernails to make these guys spill the beans. We'll assign each one a probability of .9 of keeping the secret. Now, take a hundred such characters and--oops! The secret gets out 99.997 % of the time. Hmmm, that won't do either. We'll raise our super-agents' ability to keep their dark secret to .95, and now the truth is revealed only 99.4% of the time.

This isn't going well for the fantasy side. I know: we'll make them all demigods and boost their ability to keep a secret to .97! We'll overlook the fact that finding these extraordinary specimens might prove tricky. This truly special group will let the cat out of the bag a mere 95.2% of the time.

But right at this juncture, when your prospects of being taken seriously have skyrocketed to almost five percent, an inconvenient problem arises. Your imaginary conspiracy does not consist of a hundred evildoers. It must number in the thousands. The list has been posted many times, and will not be repeated here in full, but this invisible army has to, just for starters, cow into silence all the Democrats in the military (we will assume that EVERY Republican in the military is eager to sign off on mass murder), the FAA, the air traffic controllers, all the researchers at NIST, FEMA, the members of ASCE, the forensic examiners, the fire and police departments of NYC and Washington, D.C., the seismologists at the Lamont-Doherty labs, the editors who printed the passenger manifests, the Boeing Corporation--this list gets m-u-c-h longer.

But we'll reduce the number of people complicit in this heinous crime to an implausibly low estimate of five hundred. We'll also raise their probability of keeping mum to an absurd .99. Guess what? The secret gets out 99.3% of the time.

And in almost six years ABSOLUTELY NO ONE has talked.

Sure, that could happen. Thousands of ordinary people would have no motive to blow the whistle on a mass murder of their compatriots. The gigantic invisible army (who funds it, incidentally?) intimidates, well, everyone.

I call it, The Impossibly Vast Conspiracy.

I do not propose any likely scenario for a conspiracy, but your theory is completely full of holes. The level of any possible conspiracy has not been established. Maybe it was as small as Cheny and Rumsfeld. Maybe it was as simple as knowing it was going to happen and scheduling the war games. My main point is that almost no one needed to know they were involved.

If it was larger maybe people aren't willing to lose their jobs or worse. Take the cowed democrats for example. Maybe sending anthrax to two leading democrats scares the **** out of people.

For CD to be a possiblity, according to Bazant (i.e. if one floor fails, all floors fail) you only need to plant cutter charges on one floor (47 columns) somewhere between the 79th and 96th floor. I'm no demolition expert, but I can't imagine it would take more than two guys. Maybe al Qaeda infiltrated Jeb's security company. If they were insiders, maybe they have the firm conviction that they are saving peoples lives by bringing the towers straight down rather than having them fall sideways.

Remember, your argument applies to al Qaeda also. How many leaders, handlers and planners were in on it? None of them have talked either.

Either way you slice it, your theory falls apart.

R.Mackey

17th June 2007, 02:33 PM

For CD to be a possiblity, according to Bazant (i.e. if one floor fails, all floors fail) you only need to plant cutter charges on one floor (47 columns) somewhere between the 79th and 96th floor. I'm no demolition expert, but I can't imagine it would take more than two guys. Maybe al Qaeda infiltrated Jeb's security company. If they were insiders, maybe they have the firm conviction that they are saving peoples lives by bringing the towers straight down rather than having them fall sideways.

Remember, your argument applies to al Qaeda also. How many leaders, handlers and planners were in on it? None of them have talked either.

Either way you slice it, your theory falls apart.

That's a gross oversimplification. For CD to be a possibility, you need these other things that you've conveniently neglected:

Cutter charges that survive the biggest office fires ever
Cutter charges that weren't dislodged, or wiring damaged, by the impact
Cutter charges unseen by the thousands of people working there
Cutter charges that caused exterior columns to slowly bow over the course of a half-hour
Cutter charges that didn't go BANG

...etc. The NIST report may not, by itself, eliminate all possibility of explosives. But then it's hard to prove a negative. What it does prove is that no such charges were necessary, and the phenomenon matches expectations.

I've found your comments on tower mass interesting, some even plausible. This is not.

ETA: By the way, your comment that "Al-Qaeda also hasn't talked" is totally wrong. bin Laden has issued numerous video statements claiming responsibility, and the Martyrdom Videos have aired for most if not all of the hijackers themselves. It's here on the Forum.

WildCat

17th June 2007, 02:40 PM

A mistake in the Kean Report?

How about page 305. "At 9:58:59, the South Tower collapsed in ten seconds..."
Perhaps you missed the word "significant"? The 9/11 Commission Report was not even concerned with the mechanics of collapses, but with the governments failures to prevent the attacks from happening and succeeding.

So how's that investigation into the iron spherules coming along Frank? Have you turned 120 years of high-rise construction on its head yet with your findings?

GregoryUrich

17th June 2007, 02:52 PM

Troofers always rail on about the 9/11 Commission report, yet whan asked none seems to be able to find a significant error in it. Can you point one out an error in the "Kean Commission" report you dismiss so readily?

The most obvious errors are errors of omission and failure to investigate. For example, most of the family steering committee's questions were unanswered. There are contradictions between the "Kean Commision" report and the NIST reports. If you can't find anything yourself, you are not looking.

You could start at http://www.patriotsquestion911.com/.

Gravy

17th June 2007, 03:00 PM

The most obvious errors are errors of omission and failure to investigate. For example, most of the family steering committee's questions were unanswered. There are contradictions between the "Kean Commision" report and the NIST reports. If you can't find anything yourself, you are not looking.

You could start at http://www.patriotsquestion911.com/.Of the things that are in the report, can you point to anything substantial that's wrong? For example, connections between the 9/11 terrorists, their extensive training, planning, travels, and their actions on 9/11?

GregoryUrich

17th June 2007, 03:04 PM

That's a gross oversimplification. For CD to be a possibility, you need these other things that you've conveniently neglected:

Cutter charges that survive the biggest office fires ever
Cutter charges that weren't dislodged, or wiring damaged, by the impact
Cutter charges unseen by the thousands of people working there
Cutter charges that caused exterior columns to slowly bow over the course of a half-hour
Cutter charges that didn't go BANG

...etc. The NIST report may not, by itself, eliminate all possibility of explosives. But then it's hard to prove a negative. What it does prove is that no such charges were necessary, and the phenomenon matches expectations.

I've found your comments on tower mass interesting, some even plausible. This is not.

ETA: By the way, your comment that "Al-Qaeda also hasn't talked" is totally wrong. bin Laden has issued numerous video statements claiming responsibility, and the Martyrdom Videos have aired for most if not all of the hijackers themselves. It's here on the Forum.

Like I've said again and again, and repeated above, I'm not trying to prove CD or CT. I was just giving an example of how less than 500 people would need to be involved.

Regarding al Qaeda, who talked besides the dead guys and the right handed fat guy who only looks slightly like Usama bin Ladin?

R.Mackey

17th June 2007, 03:09 PM

But it's just not that simple.

Who else? Khalid Sheikh Mohammed and Ramzi Binalshibh for starters. Their story is infinitely more credible than a coordinated mixture of aircraft and planted explosives, too.

Corsair 115

17th June 2007, 03:33 PM

I'm no demolition expert, but I can't imagine it would take more than two guys. (emphasis added) Therein lies the problem with your assessment. When one is not familiar with all the various technical aspects of a particular industry or occupation, it is easy, and perhaps even natural, to greatly oversimplify the tasks actually required by that industry/occupation.

I'm confident, for example, the average layperson who has no experience with how things are printed and published probably thinks those annoying flyers you get in your mailbox from a major retail chain are no big deal to create either. In reality, it's a large industry and a significant undertaking involving a lot of technical aspects.

beachnut

17th June 2007, 03:33 PM

Like I've said again and again, and repeated above, I'm not trying to prove CD or CT. I was just giving an example of how less than 500 people would need to be involved.

Regarding al Qaeda, who talked besides the dead guys and the right handed fat guy who only looks slightly like Usama bin Ladin?

Class, which hand do Islamic people use in public? Right

Does everyone know why? Yes, except GregoryUrich, the expert EE with very expert research capabilities. What does he know that we missed?

500, where did you pick that number from? And did you use your left hand? 500, not 4400, but 500. <500. Do you have a list? I have 19 people who were in on it, and a few support people, but I wonder if those who knew the whole story were only 7 to 10 people. I forgot how many trained as pilots.

So you post a letter on a woo woo journal of 9/11 junk and now profess you are just a... what? I find, unless you make it clear about your intent, posting on a site of junk supports those false ideas. You are a CD supporter by default. A thermite junkie. There is more evidence for that, than CD.

Right handed stuff is weak. And being left handed in Islam means never eating with you left hand (in public)! Darn. And you thought Catholic left handed kids had it bad.

You could start at http://www.patriotsquestion911.com/ (http://www.patriotsquestion911.com/).
So you post the list of nuts. Which ones are the ones with the truth? Any of these Patriots have any idea what is going on. How many of those listed know idiots are using them as examples for 9/11 truth? But then, which ones have anything of substance. Your right hand stuff pretty much makes you a poor researcher, and a push over to fall for lies of 9/11. Wesley Clack a truther? He sure does not know how to plan ahead, I worked with him in a little war, he was not very great. What a list.

Col. Robert Bowman, PhD, U.S. Air Force - woo woo. This guy has zero stuff on 9/11, next.

Lt. Col. Jeff Latas, U.S. Air Force (ret) – woo woo two - he is a member of "Pilots for 9/11 Truth is an organization of aviation professionals and pilots throughout the globe that have gathered together for one purpose. We are committed to seeking the truth surrounding the events of the 11th of September 2001. Our main focus concentrates on the four flights, maneuvers performed and the reported pilots. We do not offer theory or point blame. However, we are focused on determining the truth of that fateful day since the United States Government doesn't seem to be very forthcoming with answers." Not one theory of person to blame, so say PFT. ZIP. But that is a lie, their leader claims 77 did not hit the Pentagon. WOO to the max, since DNA and FDR prove 77 did. Thousand of pieces of evidence make the entire PFT null and void.

Please tell me you have something better than this web site of junk 9/11 stuff. You are a truther, and you continue ot post truther stuff. http://www.patriotsquestion911.com/ the web site of many woos. Should I check on more?

Could not find one fact to back up anything from 9/11 truth from http://www.patriotsquestion911.com/. Perfect record of zero. 0

Truther 0 - Terrrorist 3.

Why not tell me which ones are the ones you think have something so I can see why you are wrong again. Who is your favorite person in the 9/11 truth movement?

stateofgrace

17th June 2007, 03:59 PM

Like I've said again and again, and repeated above, I'm not trying to prove CD or CT. I was just giving an example of how less than 500 people would need to be involved.

I would like to put a bit of perspective on this for you. You say less than 500 people; ok let’s go along with this. Can you imagine a single person being approached and willing to go along with a plan to commit mass murder of 3000 of his/hers own citizens? Just one, then add another person and another until you get it up to the final figure you wish to put on it. So beforehand you have recruited an unknown amount of people that are prepared to carry out mass murder on your behalf. You are now relying upon an unknown, that unknown is whether or not these people will remain loyal to you, do as you ask and carry this out. Unless every single person that is approached to do this keeps quiet and is completely loyal to you it is game over before it starts.

So ok you get over the first hurdle and you have recruited a band of totally loyal people that are prepared to face certain death by the gas chamber if caught and carry out mass murder for you. Now comes the second hurdle, actually doing the prep work beforehand and not getting caught. Not being seen planting explosives inside the towers or WTC 7 or which ever other building you believe was blown up. This is all done before any planes are involved and done in total secrecy.

So, ok having over come these two hurdles, you have recruited a band of highly trained completely loyal people who are going to commit mass murder for you and they have prepped the site in total secretary. The next hurdle is the planes, knowing exactly when and where they are going to hit the towers, knowing that they are going to miss all the explosives and that they will not knock over the building immediately. You have to know that any fires that were caused will not damage the explosives and you have know that the fires themselves will not be intense enough to cause further damage which would inadvertently lead to a catastrophic structural failure, which is actually what you want anyway.

From there on it is easy, simply wait for suicidal hijackers to fly the planes into the buildings and your men then swing into action, that being on your behave they commit mass murder of 3000 of their fellow countrymen. Of course this was done in front of the entire planet so the structural failure of each of these building which you actually want to happen has to look as though it was caused by the planes and the fires, rather than your group of loyal mass murderers.

Everybody then packs up and heads off home, where they remain for years and years, totally loyal to you, not saying a word. They have absolutely no guilt,no feelings of remorse and keep their mouths shut for years, nearly six years in fact.

Now, would you feel happy to rely on so many unknowns to keep you out of the gas chamber?

GregoryUrich

17th June 2007, 04:10 PM

Mackey, or anyone else,

I'm trying to work out the dead loads from the design docs in NIST. I have found unit dead load (CDL + SDL) for outside of the core for everything except the sublevels. I can't find a unit dead load for inside the core.

In NCSTAR1-1A there are some scanned design documents on pgs. 7-9 but there isn't any summary like there is for outside the core. I'm contemplating using the SDLs from 1-2A pg. 137 which is simplified for NIST's model. I assume these include floor topping, ceiling, and partitions. There are a few issues regarding dead loads in the core which I'm unsure about.

1. The service and elevator shaft areas are not listed. These are mostly empty but have ducts, elevator tracks, electrical cables, plumbing, etc. How can I come up with a reasonable estimate for these?

2. Regarding core column fire proofing, I am considering using 2" gypsum everywhere. This will be a pain in the butt because I need to calculate the surface area for all of the columns but such is life. I am planning on ignoring tile because the majority of columns are unexposed.

3. Is it reasonable to assume spray on fire proofing for the floor beams and steel deck?

Regarding live loads:

The probalistic average live loads in accord with Choi (1989) "Live load model for office buildings" are around 10 psf. With 200 persons on a floor (floor area outside the core), which would give 155 sq ft/person so the weight per person is 1550. If anything, computers have gotten lighter and there is less paper so I think it is reasonable. Choi gets into predicting maximum loads which is the primary reason for "over designing". For example, you can't have the floor cave in just because 20 people crowd someones cubicle at a christmas party.

Choi doesn't include loads for partitions, but the design documents give an NY code uniform equivalent of 6 psf. This would give a total of 16 psf for live load outside the core. Do you think this is reasonable?

GregoryUrich

17th June 2007, 04:29 PM

Therein lies the problem with your assessment. When one is not familiar with all the various technical aspects of a particular industry or occupation, it is easy, and perhaps even natural, to greatly oversimplify the tasks actually required by that industry/occupation.

I'm confident, for example, the average layperson who has no experience with how things are printed and published probably thinks those annoying flyers you get in your mailbox from a major retail chain are no big deal to create either. In reality, it's a large industry and a significant undertaking involving a lot of technical aspects.

You seem confident that it is more complex than I think it is. Are you an expert? How much do you know about my knowledge in related areas?

GregoryUrich

17th June 2007, 04:32 PM

I would like to put a bit of perspective on this for you. You say less than 500 people; ok let’s go along with this. Can you imagine a single person being approached and willing to go along with a plan to commit mass murder of 3000 of his/hers own citizens? Just one, then add another person and another until you get it up to the final figure you wish to put on it. So beforehand you have recruited an unknown amount of people that are prepared to carry out mass murder on your behalf. You are now relying upon an unknown, that unknown is whether or not these people will remain loyal to you, do as you ask and carry this out. Unless every single person that is approached to do this keeps quiet and is completely loyal to you it is game over before it starts.

So ok you get over the first hurdle and you have recruited a band of totally loyal people that are prepared to face certain death by the gas chamber if caught and carry out mass murder for you. Now comes the second hurdle, actually doing the prep work beforehand and not getting caught. Not being seen planting explosives inside the towers or WTC 7 or which ever other building you believe was blown up. This is all done before any planes are involved and done in total secrecy.

So, ok having over come these two hurdles, you have recruited a band of highly trained completely loyal people who are going to commit mass murder for you and they have prepped the site in total secretary. The next hurdle is the planes, knowing exactly when and where they are going to hit the towers, knowing that they are going to miss all the explosives and that they will not knock over the building immediately. You have to know that any fires that were caused will not damage the explosives and you have know that the fires themselves will not be intense enough to cause further damage which would inadvertently lead to a catastrophic structural failure, which is actually what you want anyway.

From there on it is easy, simply wait for suicidal hijackers to fly the planes into the buildings and your men then swing into action, that being on your behave they commit mass murder of 3000 of their fellow countrymen. Of course this was done in front of the entire planet so the structural failure of each of these building which you actually want to happen has to look as though it was caused by the planes and the fires, rather than your group of loyal mass murderers.

Everybody then packs up and heads off home, where they remain for years and years, totally loyal to you, not saying a word. They have absolutely no guilt,no feelings of remorse and keep their mouths shut for years, nearly six years in fact.

Now, would you feel happy to rely on so many unknowns to keep you out of the gas chamber?

With all due respect, I am not interested in continuing discussion in this area because I think it is pointless. I'm not supporting CD or CT no matter what anyone says. I think there are questions worth looking into. That is all.

Gravy

17th June 2007, 04:35 PM

Regarding al Qaeda, who talked besides the dead guys and the right handed fat guy who only looks slightly like Usama bin Ladin?

You mean this guy?
Aljazeera.Net - Full transcript and video of bin Ladin's 2004 "Security" speech/threat (http://english.aljazeera.net/English/archive/archive?ArchiveId=7403)

This guy?
Mike W. of 911myths.com on Osama bin Laden confessions, al Qaeda responsibility (http://forums.randi.org/showpost.php?p=2242004&postcount=195%20)

This guy?
2006: Aljazeera airs pre-9/11 tape of bin Laden meeting with some hijackers (http://abcnews.go.com/International/wireStory?id=2406059)

These guys?
The Usual Suspects: Bin Laden & Hijacker video confessions.Part 1 (http://www.youtube.com/watch?v=uu6pZ6BPSuo) – Part 2 (http://www.youtube.com/watch?v=aBa252lC4uA) – Part 3 (http://www.youtube.com/watch?v=ighjUx7H03I) – Part 4 (http://www.youtube.com/watch?v=LfuZFU39XKI)

These guys?
al Qaeda names 20th Hijacker: Turki bin Fheid al-Muteiri -- Fawaz al-Nashmi (http://forums.randi.org/showpost.php?p=1701208&postcount=44)

These guys?
The 19 Martyrs Video stills (http://ee.1asphost.com/raehatualmisk/19.html)
Atta & Jarrah videos (http://tailrank.com/613215/Mohammed-Atta-Video-Released)

These guys?
Official: 15 of 19 hijackers were Saudi (http://www.usatoday.com/news/world/2002/02/06/saudi.htm)

This guy?
Interview with brother of two hijackers Waleed Dateline NBC (http://forums.randi.org/showpost.php?p=1882207&postcount=3278)

This guy?
Zacarias Moussaoui Prosecution Trial Exhibits (http://www.vaed.uscourts.gov/notablecases/moussaoui/exhibits/prosecution.html)
USA v. Zacarias Moussaoui - Trial Transcripts (http://cryptome.quintessenz.at/mirror/usa-v-zm-dt2.htm)

This guy?
Germany: 9/11 hijackers' friend guilty of aiding murder (http://www.cnn.com/2006/WORLD/europe/11/16/germany.911/index.html)

I await your reply.

GregoryUrich

17th June 2007, 04:36 PM

R.Mackey

17th June 2007, 04:39 PM

You need to read up on this. They admitted their involvement to Al-Jazeera in 2002, prior to their arrest.

stateofgrace

17th June 2007, 04:41 PM

With all due respect, I am not interested in continuing discussion in this area because I think it is pointless. I'm not supporting CD or CT no matter what anyone says. I think there are questions worth looking into. That is all.

Aren't those guys orange suiters who have been tortured for 5 years?

Indeed,I see you are not.

GregoryUrich

17th June 2007, 04:43 PM

You mean this guy?
Aljazeera.Net - Full transcript and video of bin Ladin's 2004 "Security" speech/threat (http://english.aljazeera.net/NR/exeres/79C6AF22-98FB-4A1C-B21F-2BC36E87F61F.htm)

This guy?[SIZE=2]
Mike W. of 911myths.com on Osama bin Laden confessions, al Qaeda responsibility (http://forums.randi.org/showpost.php?p=2242004&postcount=195%20)

...

I'll have to get back to you Gravy, that's quite a homework assignment. It's late over here so you guys will have to find someone else to edify this evening.

GregoryUrich

17th June 2007, 04:52 PM

You need to read up on this. They admitted their involvement to Al-Jazeera in 2002, prior to their arrest.

You are right. I need to read up on that.

Somehow I accidently got myself involved in a big discussion regarding the feasibility of CT. Anyone who's interested please start a new thread. I promise I will go nowhere near it.

Meanwhile, I would be very appreciative if you have any input regarding my post above (CDL, SDL, and LL).

GregoryUrich

17th June 2007, 04:54 PM

Indeed,I see you are not.

Somehow I accidently got myself involved in a big discussion regarding the feasibility of CT. Anyone who's interested please start a new thread. I promise I will go nowhere near it.

stateofgrace

17th June 2007, 04:58 PM

Somehow I accidently got myself involved in a big discussion regarding the feasibility of CT. Anyone who's interested please start a new thread. I promise I will go nowhere near it.

Of course, I fully understand, please continue to concentrate on the piece of the jigsaw that no matter how many times you reshape it, it will never fit into the big picture.

twinstead

17th June 2007, 05:52 PM

I'll have to get back to you Gravy, that's quite a homework assignment. It's late over here so you guys will have to find someone else to edify this evening.

Yea. Nice retort.

Now take your time and 'get back to' him as soon as you can, m'kay?

beachnut

17th June 2007, 06:00 PM

Mackey, or anyone else,

2. Regarding core column fire proofing, I am considering using 2" gypsum everywhere. This will be a pain in the butt because I need to calculate the surface area for all of the columns but such is life. I am planning on ignoring tile because the majority of columns are unexposed.

3. Is it reasonable to assume spray on fire proofing for the floor beams and steel deck?

I thought the columns had 3 inches of wallboard.

You could start at http://www.patriotsquestion911.com/ (http://www.patriotsquestion911.com/). who on this long list has something useful. You did bring up this set of people. Who are the ones with the goods?

stateofgrace

17th June 2007, 06:10 PM

who on this long list has something useful. You did bring up this set of people. Who are the ones with the goods?

Don’t forget Beachnut he is not interested in the big discussion, he has said so. This is why he brings these things up, because he is not interested in the big picture.

If you are not interested Greg why bring it up ?

Carefulplease

17th June 2007, 08:01 PM

I haven't read this whole thread. Has anyone proposed this method already for calculating the weights of the upper WTC stories?

forum.physorg.com/index.php?showtopic=7444&view=findpost&p=122431

Basically, you sum the column loads on all 287 columns at one level to get the weight of the tower block above. You subtract two consecutive levels to get the weight of one typical storey (tenant floor, mechanical floor or hat truss floor)

This being based on the data NIST collated for the purposes of the Global Model, it should include everything, including the weight of the aircraft wreckage in the post-impact tables.

I've copied all these in Excel tables so as to get the weight of all the modeled floors.

Carefulplease

17th June 2007, 08:03 PM

15 posts! At last, I am able to post URLs

http://forum.physorg.com/index.php?showtopic=7444&view=findpost&p=122431

beachnut

17th June 2007, 08:48 PM

Don’t forget Beachnut he is not interested in the big discussion, he has said so. This is why he brings these things up, because he is not interested in the big picture.

If you are not interested Greg why bring it up ?
He says he is not a 9/11 truth person, but posts the bigest 9/11 truth sites around.

Does Wesley Clark know he is on a list of fools? Do those on the list know they are on a list to fool idiots? http://www.patriotsquestion911.com/ (http://www.patriotsquestion911.com/)

shagster

17th June 2007, 09:33 PM

beachnut

17th June 2007, 09:52 PM

Upper block mass using values in NIST NCSTAR 1-6d, p240 in pdf (p176)

WTC1 column loads at 96-97 (loading due to stories 97-110; 14 stories)
peri: 11065 + 11145 + 8012 + 8040 = 38262 kips
core: 41633 kips
total: 79895 kips = 36.3E6 kg

WTC2 column loads at 81-82 (loading due to stories 82-110; 29 stories)
peri: 12367 + 12292 + 17728 + 17673 = 60060 kips
core: 71824 kips
total: 131884 = 59.9E6 kg

BZ estimates of upper block mass:

WTC1: 58E6 kg
WTC2: 87E6 kg

Compare BZ estimate with NIST values:

WTC1: 58/36.3 = 1.60
WTC2: 87/59.9 = 1.45

Compared with NIST values, BZ overestimated the upper block masses by 60% and 45%.
Or NIST underestimated. But what does it mean? It does not mean global collapse could not happen. That was proved on 9/11, global collapse did happen. Does global collapse happen with less weight? What about Ross, what did Ross use?

With less weight, does that mean the structure below is weaker too. If someone over estimates the upper weight, did they also over estimate the strength of the upper portion below the impact? It appears, no matter how you model the WTC, the WTC towers failed and fell due to impact and fire. I have to go back and talk to Robertson each time and he said the impacts were an order of magnitude greater than the impacts they had planned on for aircraft. 7 to 11 times greater impact energy from aircraft, and fire now inserted into the building, whereas if the plane was at design speed, most of the fire would be outside from the jet fuel.

Robertson had to have a say, he built the towers, he was the chief structural engineer. The buck stops with Robertson. See what he said. What do you think? Run the numbers, what is the minimum weight needed to sustain a global collapse?

Gravy

17th June 2007, 09:52 PM

Welcome to the forum, Carefulplease and shagster. I've suspected that Bazant overestimated the upper block masses, but never looked further into it. Your method and numbers look good. According ot BZ and BV (2006), though, using NIST's masses would have also resulted in global collapse, and that's with the very conservative assumptions of equal load distribution and axial column loading. If that is true (my math and physics skills are poor), then the question of NIST's accuracy comes into play. I guess that's what Gregory Urich is working on.

Edit: shagster, your post is gone, but lives on in beachnut's memory. Did you forget something?

shagster

17th June 2007, 10:03 PM

I corrected some values in the post. Beachnut's post is the old one that has an error. I use 14 and 29 stories to represent the upper block mass above the central region of the aircraft impacts.

Gravy

17th June 2007, 10:06 PM

I corrected some values in the post. Beachnut's post is the old one that has an error.Thanks.

Corsair 115

17th June 2007, 10:08 PM

You seem confident that it is more complex than I think it is. Are you an expert? How much do you know about my knowledge in related areas?I suggest you re-read my comment. You are the one who explicitly stated you were not a demolitions expert, and yet you confidently proclaimed that the alleged demolition could have been achieved with no more than two persons. I cannot see how you can reconcile these two things.

If you're not an expert, if you're not familiar with the workings of that industry/occupation, then on what basis do you make your claim that you can't imagine it taking more than two people? Just because you don't think it could be that complicated? Sorry, but that's just a complete guess on your part.

My comment was intended as a caution for you, or anyone else, that to assume that a task isn't complicated simply because on its face you can't perceive it as being complicated is an unwise assumption to make. There are usually many more details and technicalities to a particlar profession than may appear to be the case at face value. My example of retail flyers was an example attempting to illustrate that (and one I am familiar with since I used to work in that field).

shagster

17th June 2007, 10:08 PM

The NIST FEA model that was used to calculate the lateral sway period of the towers agrees closely with measured lateral sway periods. The tower mass in the NIST model can't be far off from the actual value.

shagster

17th June 2007, 10:13 PM

Carefulplease

17th June 2007, 10:15 PM

beachnut

17th June 2007, 10:17 PM

I corrected some values in the post. Beachnut's post is the old one that has an error. I use 14 and 29 stories to represent the upper block mass above the central region of the aircraft impacts.
I copied your new stuff. I think.

Gravy

17th June 2007, 10:20 PM

The NIST global FEA model has surfaced on the web. Someone obtained it from NIST after requesting it and paying a reasonable processing fee for it. I've run it on SAP2000 software but only briefly. We should be able to extract the mass above any floor using the software. I haven't taken the time to do this yet.For those who can run it, the NIST global model is here. (http://razor.occams.info/nist-wtc/)

Carefulplease

17th June 2007, 10:31 PM

For those who can run it, the NIST global model is here. (http://razor.occams.info/nist-wtc/)

He got it for 58$! I knew NIST had claimed the global model was available upon request for a fee. I was expecting the fee to be 20,000$ or something. This is pretty much as good as the original structural blueprints, and even better in some respects (live load details, etc). This is something the Truth Movement has been eagerly awaiting to ignore for years!

Carefulplease

17th June 2007, 10:48 PM

Welcome to the forum, Carefulplease [...]
Thanks Gravy

Carefulplease

17th June 2007, 10:54 PM

The NIST global FEA model has surfaced on the web. Someone obtained it from NIST after requesting it and paying a reasonable processing fee for it. I've run it on SAP2000 software but only briefly. We should be able to extract the mass above any floor using the software. I haven't taken the time to do this yet.

Great. I can't wait to see the weights all the way down.

P.S. How many shell elements were required for each horizontal thermite cutter charge?

Gravy

17th June 2007, 11:02 PM

This is something the Truth Movement has been eagerly awaiting to ignore for years!A phrase destined to become a classic!

AZCat

17th June 2007, 11:15 PM

Welcome to the JREF, Carefulplease! Nice to see you here too.

R.Mackey

17th June 2007, 11:27 PM

This is something the Truth Movement has been eagerly awaiting to ignore for years!

That is damn funny. Welcome.

It should be pointed out that the NIST model also makes a fairly low service load assumption, and its overall mass total can and should be challenged.

To Gregory Urich, your initial assumptions look OK to me. I think a more detailed "bottoms-up" weight estimate would be a useful comparison. There may be adjustments in there that we need to make later on, but if you want to do it in detail, you've probably got a good starting point.

It would be quite interesting if the two approaches converge, no?

Personally, at this point I do indeed expect to find that Bazant and Zhou's estimate is high, and that Gregory Urich's initial estimate is low. I'm still reminded that the Sears Tower estimate, which should have a roughly similar mass per square foot value, is substantially lower than the high estimates would have us conclude. I'm still not sure why, but I suspect leaving out the basement and differing estimates of service load are the key.

I also don't expect this to materially change our opinions regarding the inevitability of collapse, or the timing.

GregoryUrich

18th June 2007, 12:48 AM

I suggest you re-read my comment. You are the one who explicitly stated you were not a demolitions expert, and yet you confidently proclaimed that the alleged demolition could have been achieved with no more than two persons. I cannot see how you can reconcile these two things.

If you're not an expert, if you're not familiar with the workings of that industry/occupation, then on what basis do you make your claim that you can't imagine it taking more than two people? Just because you don't think it could be that complicated? Sorry, but that's just a complete guess on your part.

My comment was intended as a caution for you, or anyone else, that to assume that a task isn't complicated simply because on its face you can't perceive it as being complicated is an unwise assumption to make. There are usually many more details and technicalities to a particlar profession than may appear to be the case at face value. My example of retail flyers was an example attempting to illustrate that (and one I am familiar with since I used to work in that field).

I can't tell you how enlightened I feel.

Since our hypothetical insider won't need to:

order and stock the raw materials
manufacture the explosives, radios, and timers
distribute the explosives via the postal service

the job is considerably easier.

The job consists of removing fire protection from columns, simple mechanical mounting of devices and radio ignition devices. Oh, then the hard part...press the button. Since the job doesn't have to be pretty, no timing and computer controlled seqencing is required. This would be somewhat different than a normal CD where placement, timing, and sequence is crucial--in order to achieve a neat and clean implosion.

Go to a demolition equipment site. Check out the gear. This is not rocket science.

I'm not saying this is what happened. I'm not saying I could do it. I'm saying two demolition techs could do it and that one wouldn't need a conspiracy of 500 people to do it.

For your edification, I do have a bit of experience in related areas:

I have designed and built digital timing devices
I worked on electro-mechanical assembly of military radios and the US Naval multicoupler (impedence matching cabinet for radio gear)
I have worked with mechanical installation
I have worked daily, for 20 years, with software systems (including integration platforms, banking, supply chain management, logistics, search engines, telecommunications, etc.) that are 10 times as complicated as this problem
I see and assess complexity in nearly every software or telecom project I am involved with

Again, one wouldn't have to design and build the components. Just install them and press the button.

You are saying it is difficult and that I couldn't possibly understand the complexity. My guess is you are on your first job. Show me the complexity and what I couldn't possibly understand.

GregoryUrich

18th June 2007, 12:54 AM

I've got pretty much the same figures, unsurprisingly. I don't know how Bazant and Zhou arrived at their estimates. The more recent paper by Bazant, Le, Greening and Benson assumes that the mass is "almost 500,000 tons". They use a distribution (from the top down to the bottom of the bath-tub):

mu(z) = k_0*exp(k_2*z) + k_1

The values of the constants are unspecified. Maybe Apollo20 will inform us.

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=125&topic_id=159282&mesg_id=159611

I calculated the mass from Bazant et al.'s specific gravities and got 566,000 short tons so they are contradicting themselves.

GregoryUrich

18th June 2007, 01:01 AM

That is damn funny. Welcome.

It should be pointed out that the NIST model also makes a fairly low service load assumption, and its overall mass total can and should be challenged.

To Gregory Urich, your initial assumptions look OK to me. I think a more detailed "bottoms-up" weight estimate would be a useful comparison. There may be adjustments in there that we need to make later on, but if you want to do it in detail, you've probably got a good starting point.

It would be quite interesting if the two approaches converge, no?

Personally, at this point I do indeed expect to find that Bazant and Zhou's estimate is high, and that Gregory Urich's initial estimate is low. I'm still reminded that the Sears Tower estimate, which should have a roughly similar mass per square foot value, is substantially lower than the high estimates would have us conclude. I'm still not sure why, but I suspect leaving out the basement and differing estimates of service load are the key.

I also don't expect this to materially change our opinions regarding the inevitability of collapse, or the timing.

The correct mass and proper sequence of "crush up" first makes a huge difference in the timings. If Bazant is wrong about the amount of ejected debris this also makes a significant difference. I still think 20% is very low. I think we will find that the gravity driven collapse time will end up being around 20 seconds.

uk_dave

18th June 2007, 01:17 AM

The job consists of removing fire protection from columns, simple mechanical mounting of devices and radio ignition devices. Oh, then the hard part...press the button. Since the job doesn't have to be pretty, no timing and computer controlled seqencing is required. This would be somewhat different than a normal CD where placement, timing, and sequence is crucial--in order to achieve a neat and clean implosion.

Interesting. Is it your belief that the demolition was a single act which caused sufficient damage to the structure for a progressive collapse to take place?

If so, can you identify at what point the demolition was initiated, and how it differed from the appearance of the progression?
Also, how much more damage was needed to be produced by the cd which was not provided by the airplane crash?

If not, can you explain how a perfectly timed progression of demolition down through the building was achieved without timers and controlled sequencing?
Also, how was this complex cd installation able to survive a chaotic airplane crash and subsequent fires?

GregoryUrich

18th June 2007, 01:41 AM

Interesting. Is it your belief that the demolition was a single act which caused sufficient damage to the structure for a progressive collapse to take place?

If so, can you identify at what point the demolition was initiated, and how it differed from the appearance of the progression?
Also, how much more damage was needed to be produced by the cd which was not provided by the airplane crash?

If not, can you explain how a perfectly timed progression of demolition down through the building was achieved without timers and controlled sequencing?
Also, how was this complex cd installation able to survive a chaotic airplane crash and subsequent fires?

I AM NOT TRYING TO PROVE CD OR CT. IT IS NOT MY BELIEF THAT DEMOLITION CAUSED THE COLLAPSE. This started as a HYPOTHETICAL argument about the probability of a conspiracy other than the offical CT. It really belongs on another thread.

To answer your questions:

Bazant, according to most people here has proved that one only needs to remove support on one floor for total collapse to be inevitable. So theoretically you don't need a timed progression. I agree, any explosives surviving the plane crash is a unlikely, if they were in that area. Also it would be difficult to predict the impact level without expanding the scope of the hypothetical conspiracy.

We could argue indefinitely about this hypothetical possibility but at this point I have no reason to pursue it.

There are other alternative explanations for contribution to collapse such as:

fuel air explosions in shafts
overloading of the structure
design defects
construction defects

Nonetheless, until gravity driven collapse is proven unlikely I have no reason to pursue alternative explanations.

LashL

18th June 2007, 01:52 AM

I'm not saying this is what happened. I'm not saying I could do it. I'm saying two demolition techs could do it and that one wouldn't need a conspiracy of 500 people to do it.

Hmm. In light of the fact that you admittedly have no knowledge or experience in relevant fields relating to this issue, upon what do you base your conclusion that "two demolition techs could do it and that one wouldn't need a conspiracy of 500 people to do it"? Please be specific.

For your edification, I do have a bit of experience in related areas:
I have designed and built digital timing devices
What type of digital timing devices? Please be specific.

I worked on electro-mechanical assembly of military radios and the US Naval multicoupler (impedence matching cabinet for radio gear)
1) What does "worked on" mean in that sentence?
2) How is this relevant to your hypothesis?

I have worked with mechanical installation
1) What does "worked with" mean in that sentence?
2) What type of "mechanical installation" are you talking about?
3) How is this relevant to your hypothesis?

I have worked daily, for 20 years, with software systems (including integration platforms, banking, supply chain management, logistics, search engines, telecommunications, etc.) that are 10 times as complicated as this problem

Ahh, you're a software techie. Hurrah. But back to your post,
1) This is relevant to your hypothesis how?
2) How did you ascertain that your work in software logistics and such is "10 times as complicated" as the issues pertaining to the collapse of the Twin Towers (and if your daily work is "10 times more complicated", why is it that you are still struggling with the basics regarding the towers?)

I see and assess complexity in nearly every software or telecom project I am involved with

And this is relevant to your hypothesis how?

GregoryUrich

18th June 2007, 07:29 AM

Hmm. In light of the fact that you admittedly have no knowledge or experience in relevant fields relating to this issue, upon what do you base your conclusion that "two demolition techs could do it and that one wouldn't need a conspiracy of 500 people to do it"?

You could apply your same critical style to Pomeroo's assertion that it would require 500 people.

It's not my hypothesis. It's a hypothetical scenario. I'm not interested in discussing this further

Belz...

18th June 2007, 09:38 AM

I'm no demolition expert, but I can't imagine it would take more than two guys.

"Good morning, mister Phelps. Al Qaeda is a terrorist organisation, led by this man, Ossama Bin Laden, bent on the destruction of western ideals. We need a decisive strike to remove him and his organisation from their bases in Afganistan. Unfortunately the US people are not in favour of invading this ressource-less country. The administration has decided that destroying the World Trade Center and blaming it on the terrorists will change that. Your mission, should you choose to accept it, is to hijack four commercial jets, ram them into the World Trade Center, Pentagon and White House, and plant explosives in each of the buildings after the fact so that collapse will be total. As always, should you or any of your IM force be caught or killed, the Secretary will disavow any knowledge of your actions. This recording will self-destruct in 5 seconds. Good luck, Jim."

Yeah, sure.

Corsair 115

18th June 2007, 12:13 PM

Since our hypothetical insider won't need to:

order and stock the raw materials
manufacture the explosives, radios, and timers
distribute the explosives via the postal service

the job is considerably easier. Uh, how many demolition companies manufacture their own explosives or get them delievered in the mail anyway?

The job consists of removing fire protection from columns, simple mechanical mounting of devices and radio ignition devices. Oh, then the hard part...press the button. And how do they access those portions of the building? How long does it take to remove the fire protection? How long to install the explosives on just the right columns in just the right places? How long to ensure all the wiring and detonators are done correctly? Any estimates? Or are you again assuming this is something that can be knocked off in ten minutes because it doesn't sound complicated?

(I'd also ask how these planted explosives were shielded from damage after the jets impacted the buildings, how these explosives were shielded from the resulting heat and fires, how the jets managed to crash into each WTC tower at just the right location as to match were these explosives were planted. But I'll leave those questions out for now.)

Since the job doesn't have to be pretty, no timing and computer controlled seqencing is required. Why do you assume this? It looks like the old "it doesn't look complicated to do therefore it must not be complicated to do" bug raising its head again.

Go to a demolition equipment site. Check out the gear. This is not rocket science. One might conclude from this statement that knocking a building down with explosives is a relatively easy task that anybody can do without much trouble. Is that what you are saying?

I'm not saying this is what happened. I'm not saying I could do it. I'm saying two demolition techs could do it and that one wouldn't need a conspiracy of 500 people to do it. But only if it as uncomplicated and easy to do as you think it is. Again, I point out that you are assuming it would be as easy to do as you make it out to be. Reality tends not to to work that way and things are often more involved or complicated than it might seem on the surface.

For your edification, I do have a bit of experience in related areas:

I have designed and built digital timing devices
I worked on electro-mechanical assembly of military radios and the US Naval multicoupler (impedence matching cabinet for radio gear)
I have worked with mechanical installation
I have worked daily, for 20 years, with software systems (including integration platforms, banking, supply chain management, logistics, search engines, telecommunications, etc.) that are 10 times as complicated as this problem
I see and assess complexity in nearly every software or telecom project I am involved with
Interesting, but none of that has anything to do with working with explosives, nor their handling and installation for the purposes of destroying buildings. If I wanted to ask about working with software systems, then it seems you'd be the guy to ask.

Again, one wouldn't have to design and build the components. Just install them and press the button. Except you are assuming, without providing any evidence, that such installation would be simple and easy to do.

You are saying it is difficult and that I couldn't possibly understand the complexity.No, I am saying you are underestimating the complexity of the steps involved.

Simple question to illustrate the point: that twenty or thirty page full-colour flyer you get in your mailbox from Sears or whichever, how many days in advance do you think that flyer was first created? A week? Two weeks? A month? What steps do you think are needed to create a publication like that which 99% of people probably throw out as soon as they get it?

Carefulplease

18th June 2007, 12:19 PM

I calculated the mass from Bazant et al.'s specific gravities and got 566,000 short tons so they are contradicting themselves.

Thanks GregoryUrich.

They seem to be using the metric system throughout. 566,000 short tons make 513,600 metric tons (or tonnes). What do you refer to as specific gravities? I'd like to look further into this.

pomeroo

18th June 2007, 12:24 PM

You could apply your same critical style to Pomeroo's assertion that it would require 500 people.

It's not my hypothesis. It's a hypothetical scenario. I'm not interested in discussing this further

You didn't read my post carefully. I pared down the number of people complicit in the mass murder to five hundred. That includes the conspirators themselves and all those they managed to cow into silence. The actual number must be considerably larger--NIST alone employed over two hundred researchers and consulted with another eight hundred outside authorities. The assigned probability of keeping the terrible secret for everyone who knows the "truth", .99, is absurdly high: a Democrat working for FEMA, for instance, has no conceivable motive for maintaining silence. My point was to demonstrate that the fantasists' imaginary conspiracy will unravel very close to 100% of the time.

rwguinn

18th June 2007, 01:13 PM

Uh, how many demolition companies manufacture their own explosives or get them delievered in the mail anyway?

And how do they access those portions of the building? How long does it take to remove the fire protection? How long to install the explosives on just the right columns in just the right places? How long to ensure all the wiring and detonators are done correctly? Any estimates? Or are you again assuming this is something that can be knocked off in ten minutes because it doesn't sound complicated?

(I'd also ask how these planted explosives were shielded from damage after the jets impacted the buildings, how these explosives were shielded from the resulting heat and fires, how the jets managed to crash into each WTC tower at just the right location as to match were these explosives were planted. But I'll leave those questions out for now.)

Why do you assume this? It looks like the old "it doesn't look complicated to do therefore it must not be complicated to do" bug raising its head again.

One might conclude from this statement that knocking a building down with explosives is a relatively easy task that anybody can do without much trouble. Is that what you are saying?

But only if it as uncomplicated and easy to do as you think it is. Again, I point out that you are assuming it would be as easy to do as you make it out to be. Reality tends not to to work that way and things are often more involved or complicated than it might seem on the surface.

Interesting, but none of that has anything to do with working with explosives, nor their handling and installation for the purposes of destroying buildings. If I wanted to ask about working with software systems, then it seems you'd be the guy to ask.

Except you are assuming, without providing any evidence, that such installation would be simple and easy to do.

No, I am saying you are underestimating the complexity of the steps involved.

Simple question to illustrate the point: that twenty or thirty page full-colour flyer you get in your mailbox from Sears or whichever, how many days in advance do you think that flyer was first created? A week? Two weeks? A month? What steps do you think are needed to create a publication like that which 99% of people probably throw out as soon as they get it?

Actually, I have to side with GregoryUrich here--
If the intent was simply to bring down the building, no long lead time was needed--just a half-dozen dedicated idiots with sufficient C4 to blow away about 60-75% of the columns on an individual floor, and enough time to slap them on and set them off- Individual timers, whatever.
Somebody might have noticed a few guys bringing in that much C4, and the booms would have been quite noticeable from some distance away.
The planning and time it takes for CD are merely for safety reasons--to make sure the thing falls where and when you want it to.
To simply bring it down is a lot easier, and quicker. But as many, many others and I have said, someone probably would have noticed

GregoryUrich

18th June 2007, 01:24 PM

Thanks GregoryUrich.

They seem to be using the metric system throughout. 566,000 short tons make 513,600 metric tons (or tonnes). What do you refer to as specific gravities? I'd like to look further into this.

"Specific gravity" is Bazant's terminology for density over the height of the building. This is Bazant et al.'s latest:

http://www.civil.northwestern.edu/people/bazant/PDFs/Papers/00%20WTC%20Collapse%20-%20What%20Did%20%26%20Did%20Not%20Cause%20It%20-%205-2007.pdf

GregoryUrich

18th June 2007, 01:44 PM

Uh, how many demolition companies manufacture their own explosives or get them delievered in the mail anyway?

...

Simple question to illustrate the point: that twenty or thirty page full-colour flyer you get in your mailbox from Sears or whichever, how many days in advance do you think that flyer was first created? A week? Two weeks? A month? What steps do you think are needed to create a publication like that which 99% of people probably throw out as soon as they get it?

You are the one comparing this to flyers.

Here's an introduction video from The Orica Group. By the way, it's even simpler than I thought it was:

http://www.i-konsystem.com/html2/digitalrevolution.html

Carefulplease

18th June 2007, 02:50 PM

"Specific gravity" is Bazant's terminology for density over the height of the building. This is Bazant et al.'s latest:

http://www.civil.northwestern.edu/people/bazant/PDFs/Papers/00%20WTC%20Collapse%20-%20What%20Did%20%26%20Did%20Not%20Cause%20It%20-%205-2007.pdf

This is indeed the paper I was referring to earlier. The term they use is "specific mass". I don't see how you get to 513 tonnes. What values for k_0 and k_2 do you use? The graph in fig. 1 makes it plain that the small correction from the non-linear part of the variation makes very little difference. Assuming 22m bathtub depth as in fig. 3, and 415m above ground, I obtain a value that is very close to 500,000 tonnes. I don't see that they contradict themselves.

GregoryUrich

18th June 2007, 03:43 PM

This is indeed the paper I was referring to earlier. The term they use is "specific mass". I don't see how you get to 513 tonnes. What values for k_0 and k_2 do you use? The graph in fig. 1 makes it plain that the small correction from the non-linear part of the variation makes very little difference. Assuming 22m bathtub depth as in fig. 3, and 415m above ground, I obtain a value that is very close to 500,000 tonnes. I don't see that they contradict themselves.

Here's what I did (assuming linear in top part):

avg spec mass top part (1 035 000 kg/m) x 29 floors x 3,7m = 134 032 500 kg
avg spec mass bot part (1 255 000 kg/m) x 87 floors x 3,7m = 403 984 500 kg

Total = 515 040 000 kg = 567 725 tons

Bazant says the mass was "close to 500,000 tons". Everyone I have discussed this with here interprets "tons" as short tons and "tonnes" as metric. That is why I say they contradict themselves. Maybe they meant tonnes, but either way they are way off the mark. The actual in-service weight was probably less than 300,000 short tons.

jaydeehess

18th June 2007, 03:46 PM

tsig

18th June 2007, 04:00 PM

Therein lies the problem with your assessment. When one is not familiar with all the various technical aspects of a particular industry or occupation, it is easy, and perhaps even natural, to greatly oversimplify the tasks actually required by that industry/occupation.

I'm confident, for example, the average layperson who has no experience with how things are printed and published probably thinks those annoying flyers you get in your mailbox from a major retail chain are no big deal to create either. In reality, it's a large industry and a significant undertaking involving a lot of technical aspects.

Yes I have noticed that the less I knew about something the easier it was to do.

Until I tried to do it.

Carefulplease

18th June 2007, 05:15 PM

Here's what I did (assuming linear in top part):

avg spec mass top part (1 035 000 kg/m) x 29 floors x 3,7m = 134 032 500 kg
avg spec mass bot part (1 255 000 kg/m) x 87 floors x 3,7m = 403 984 500 kg

Total = 515 040 000 kg = 567 725 tons

Bazant says the mass was "close to 500,000 tons". Everyone I have discussed this with here interprets "tons" as short tons and "tonnes" as metric. That is why I say they contradict themselves. Maybe they meant tonnes, but either way they are way off the mark. The actual in-service weight was probably less than 300,000 short tons.

OK thanks. The linearity assumption easily account for the 15,040 tonnes difference. I am pretty sure they meant to refer to 1000kg "tons". They refer to kilograms in the very same sentence. Their estimate may be high but there is no contradiction.

Corsair 115

18th June 2007, 05:23 PM

Actually, I have to side with GregoryUrich here--
If the intent was simply to bring down the building, no long lead time was needed--just a half-dozen dedicated idiots with sufficient C4 to blow away about 60-75% of the columns on an individual floor, and enough time to slap them on and set them off- Individual timers, whatever. Okay, I'll defer to you on this - if one is going to take a purely blunt force approach. But as you yourself noted, it'd involve a lot of explosives and the sound of those going off would have been unmistakable.

And as jaydeehess noted, CTers often contend the collapse of the towers was too precise to be anything other than some form of controlled demolition. If it's controlled, then it's not just a matter of stuffing the relevant parts of the building with explosives.

(There's still the question of how those explosives survived the impact of the aircraft and the subsequent fires.)

Here's an introduction video from The Orica Group. By the way, it's even simpler than I thought it was:

http://www.i-konsystem.com/html2/digitalrevolution.htmlYou perhaps should have read that site more closely. From its FAQ page (http://www.i-konsystem.com/html2/faq1.html#1) (emphasis added):

1.5 How well does the i-kon™ System work?

Extensive global applications of the i-kon™ System have demonstrated unsurpassed performance and benefits delivery in surface metal mining, quarrying & construction, demolition, open cast coal, as well as varied underground operations.

I would submit to you that there's a world of difference between using blasting to open up rockfaces in a quarry and using blasting within the restricted confines of a steel and concrete building structure in terms of the preparation time needed to ensure the job is done as desired.

Apollo20

18th June 2007, 05:25 PM

Carefulplease

18th June 2007, 06:00 PM

Carefulplease:

I do believe that an assumed value of 58,000 tonnes for the upper section of WTC 1 may be a little high. However, the collapse time is relatively insensitive to the mass of the upper section which is much more dependent on what I call E1.

Thank you Apollo20,

This, I find surprising. I agree that collapse time is insensitive to mass when E1 = 0. This is because it then only deviates from free fall time owing to momentum transfer. And "resistance" from momentum transfer is not dependant on total mass. Moreover, momentum transfer has overall a much more important effect on collapse time than structural resistance (E1/unit height) has.

However, momentum transfer is very much dependent on mass distribution over height. I would thus expect variations in mass distribution (near the impact zone) to have effects at least comparable to effects from variations in E1, at least for the acceleration during the first few seconds of the collapse.

(Edited to replace "near the top" with "near the impact zone")

Jonnyclueless

18th June 2007, 06:46 PM

Another very good point. Basically the only way to accomplish this would be to strip the walls and replace them with some sort of "explosive" drywall. And then there is the issue of making it happen sequentially. Oh, and making sure the "explosive drywall" was installed only on the floors below the impact point. I'm not trying to be a donkey about this either, i'm just trying to apply some logic .

Have you considered that maybe they were being given explosive office supplies? Apparently they had switched office suppliers just weeks before 9/11 with ties to zionists.

Those weren't your every day pens and whiteout. Oh sure it looked like toner.

OK, just wanted to get a first post out of the way and help people think outside the box and in the yard next to the house that the box was delivered.

Furcifer

18th June 2007, 07:02 PM

OK, just wanted to get a first post out of the way and help people think outside the box and in the yard next to the house that the box was delivered.

Did you see my cat in that box? His name is Shrodie, he is very shy and very elusive.

Jonnyclueless

18th June 2007, 08:00 PM

Carefulplease

18th June 2007, 08:09 PM

Did you see my cat in that box? His name is Shrodie, he is very shy and very elusive.

I might have seen it but I'm only [modulus(psi)]^2 sure.

Furcifer

18th June 2007, 08:26 PM

I might have seen it but I'm only [modulus(psi)]^2 sure.

What, you saw him? Oh well that changes everything...

Furcifer

18th June 2007, 08:35 PM

I'm not sure if this has been covered because the thread is so large. one claim I keep hearing is that NIST never tested the theory about the trusses sagging. Is this true? I could have sworn I have seen documentaries about this specific testing.

On a serious note, I've never heard why NIST didn't test 60 foot trusses. For me personally, extrapolation is perfectly acceptable in these regards, but why not test full spans?

Carefulplease

18th June 2007, 08:38 PM

I'm not sure if this has been covered because the thread is so large. one claim I keep hearing is that NIST never tested the theory about the trusses sagging. Is this true? I could have sworn I have seen documentaries about this specific testing.

Hi Jonnyclueless,

Tests were performed to see if the floor assemblies were compliant with the ASTM E 119 standard for fire resistance. These tests were performed on fire-insulated trusses. They did sag. Some failed to get a two-hour rating.

http://wtc.nist.gov/NISTNCSTAR1-6B.pdf

Carefulplease

18th June 2007, 08:48 PM

On a serious note, I've never heard why NIST didn't test 60 foot trusses. For me personally, extrapolation is perfectly acceptable in these regards, but why not test full spans?

They did perform tests on full-scale short-span (35 feet) trusses. The largest furnaces available to perform fire tests were those of Underwriters Laboratories of Canada in Toronto. They were able to verify the effects of scale through comparing the results for both full-scale and half-scale tests. To build a 60 feet furnace would have been expansive and would have provided diminishing returns.

Gravy

18th June 2007, 08:48 PM

Jonnyclueless

18th June 2007, 08:54 PM

Thanks that makes sense. But why doesn't the truth movement mention that information? Why do they leave such details out?

Gravy

18th June 2007, 08:55 PM

Hi Jonnyclueless,

Tests were performed to see if the floor assemblies were compliant with the ASTM E 119 standard for fire resistance. These tests were performed on fire-insulated trusses. They did sag. Some failed to get a two-hour rating.

http://wtc.nist.gov/NISTNCSTAR1-6B.pdfThe interesting thing is that the 35-foot truss that failed the 2-hour rating was restrained – pinned at each end – as it would be in a real building. Its failure was a surprise to researchers and led to much further research.

Gravy

18th June 2007, 08:58 PM

Welcome to the forums, Johnnyclieless.
Thanks that makes sense. But why doesn't the truth movement mention that information? Why do they leave such details out?Because the only things holding their fantasies together are lies, omissions, and misrepresentations.

Carefulplease

18th June 2007, 09:00 PM

I've got pretty much the same figures, unsurprisingly. I don't know how Bazant and Zhou arrived at their estimates. The more recent paper by Bazant, Le, Greening and Benson assumes that the mass is "almost 500,000 tons". They use a distribution (from the top down to the bottom of the bath-tub):

mu(z) = k_0*exp(k_2*z) + k_1

The values of the constants are unspecified. Maybe Apollo20 will inform us.

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=125&topic_id=159282&mesg_id=159611

For the record, this was inaccurate. This mu function was used from the top to the 81th floor and the rest of the variation was linear all the way down.

Can someone cleverer than I tell me how to solve for k in the expression
c = k*exp(k*z)
where both c and z are numerical constants?

Furcifer

18th June 2007, 09:00 PM

They did perform tests on full-scale short-span (35 feet) trusses. The largest furnaces available to perform fire tests were those of Underwriters Laboratories of Canada in Toronto. They were able to verify the effects of scale through comparing the results for both full-scale and half-scale tests. To build a 60 feet furnace would have been expansive and would have provided diminishing returns.

What? Another perfectly logical and reasonable explanation that seems almost intuitive? If I was pressed for an answer, and had utterly no clue, this would have been it. This is just another example of how disappointing this whole alleged conspiracy really is. Everything follows from logic and has a reasonable explanation.

Newtons Bit

18th June 2007, 09:03 PM

For the record, this was inaccurate. This mu function was used from the top to the 81th floor and the rest of the variation was linear all the way down.

Can someone cleverer than I tell me how to solve for k in the expression
c = k*exp(k*z)
where both c and z are numerical constants?

I believe that reduces down by taking the log of both sides. I haven't used logarithms in a long time though.

Furcifer

18th June 2007, 09:07 PM

For the record, this was inaccurate. This mu function was used from the top to the 81th floor and the rest of the variation was linear all the way down.

Can someone cleverer than I tell me how to solve for k in the expression
c = k*exp(k*z)
where both c and z are numerical constants?
and take the ln (lawn) and solve i believe. ln (c) = k^2z i think, been a while

Carefulplease

18th June 2007, 09:14 PM

I believe that reduces down by taking the log of both sides. I haven't used logarithms in a long time though.

I just get c = ln(k) + kz.

(k is the only unknown 3bodyproblem)

Furcifer

18th June 2007, 09:23 PM

oh yah, the ln(k) is a problem. hmm...that ain't right.

i'm looking at the logarithmic rules but I'm not sure. i forget how to manipulate log func'tn :(

yah, maybe newton's got it, i was going to say maybe its a graphical solution. of course i was also going to say apply Green's theorem as well, so take it with a grain of salt :) i'm looking for my old differentials text book as we speak but don't hold your breath. i been meaning to get it out since the new Bazant/Greening paper...

AZCat

18th June 2007, 09:28 PM

Can you approximate it using a partial expansion of the infinite series? Then at least you have a polynomial that is easier to work with.

e^x = sigma (n=0 to infinity) of (x^n)/(n!)

A four-term expansion give you something like this:

c = k + (k^2)*z + (k^3)*(z^2)/2 + (k^4)*(z^3)/6

Newtons Bit

18th June 2007, 09:30 PM

I just get c = ln(k) + kz.

(k is the only unknown 3bodyproblem)

Now say screw it and plug it into a formula in excel and start guessing values until the left equals the right. Numerical solutions for the win!

AZCat

18th June 2007, 09:35 PM

Carefulplease

18th June 2007, 09:48 PM

I looked at my expansion and my head started to hurt with all those terms, so I simplified even more to a two-term expansion which gives us a quadratic equation.

c = k + z*k^2
or
z*k^2 + k - c = 0

Using the quadratic formula, I can now solve for k:

k = (-1 +/- sqrt(1 - 4*z*(-c)))/(2*z)
or
k = {(-1 + sqrt(1 + 4zc))/2z), (-1 - sqrt(1+4zc))/2z)}

I have no idea what this means by now. I hope you can make something of it, Carefulplease!

Thanks for the hard work AZCat. I fear the two-term expansion might deviate too much in the range I am interested with. I might try Newtons Bit poor-man's numerical method and tell you how much yours deviates ;)

AZCat

18th June 2007, 09:56 PM

Thanks for the hard work AZCat. I fear the two-term expansion might deviate too much in the range I am interested with. I might try Newtons Bit poor-man's numerical method and tell you how much yours deviates ;)

If you give me an idea of the values you will be using, I can give an estimate of the error of the approximation. The range of possible "k" values and the value of "z" will determine the magnitude of the error.

Furcifer

18th June 2007, 09:58 PM

Maybe try one of these http://plot-function.qarchive.org/
and plot it. I'm drawing a serious blank here, you shoulda asked me 8 years ago Careful :)

R.Mackey

18th June 2007, 11:11 PM

Can someone cleverer than I tell me how to solve for k in the expression
c = k*exp(k*z)
where both c and z are numerical constants?

Solve it numerically. This is a classic transcendental equation (http://en.wikipedia.org/wiki/Transcendental_equation). Nothing else is going to work.

ETA: See also the Lambert W Function (http://en.wikipedia.org/wiki/Lambert_W_Function), though it can't be expressed in closed form, either.

Furcifer

19th June 2007, 07:16 AM

This is a classic transcendental equation (http://en.wikipedia.org/wiki/Transcendental_equation).

Oh, well there you go, it can only be solved with meditation (http://en.wikipedia.org/wiki/Transcendental_Meditation) :hypnotize

This is not the answer I would have expected from a scientist, but whatever gets the job done I guess.

shagster

21st June 2007, 12:56 AM

The correct mass and proper sequence of "crush up" first makes a huge difference in the timings. If Bazant is wrong about the amount of ejected debris this also makes a significant difference. I still think 20% is very low. I think we will find that the gravity driven collapse time will end up being around 20 seconds.

Based on the height of the rubble pile within the tower footprint and assuming that the stories were squashed down to about 10 to 15% of their original height, a total mass shedding of 20% of the tower mass isn't very low. 20% to 30% shedding is reasonable. When the shedding is higher than 30%, it becomes difficult to explain how the top of the pile could be near the bowtie level, unless the debris in the pit is considered to be loosely compacted.

The collapse duration is relatively insensitive to mass shedding. I've written a Greening type of model that accounts for a constant amount of mass shedding per story impact during crush-down. A total shedding of 30% of the tower mass adds about one second to the collapse duration compared with no shedding. That doesn't put the predicted collapse duration beyond the observed duration.

shagster

21st June 2007, 01:10 AM

The correct mass and proper sequence of "crush up" first makes a huge difference in the timings.

The mass doesn't make a huge difference in collapse duration unless the energy dissipated per story, E1, approaches the GPE released per story. In Greening's model, E1 is about one-third of the GPE in order for the model to predict the same fall rate as was observed during the first four seconds of collapse. In order for the collapse duration to start to becoming sensitive to changes in mass, the mass would need to be about one-third of its value for the GPE released per story to approach Greening's estimate of E1. Or, E1 would have to be about three times higher than Greening's estimate for the same mass.

The tower mass was probably less than the initial estimates of Greening and BZ. It's also possible that E1 was overestimated by Greening and BZ. A better approach is to consider the ratio of E1 to the amount of mass that is falling. There will be some ratio of E1/mass such that the observed collapse rate agrees most closely with the predicted rate of the collapse model.

Furcifer

21st June 2007, 05:21 AM

Based on the height of the rubble pile within the tower footprint and assuming that the stories were squashed down to about 10 to 15% of their original height, a total mass shedding of 20% of the tower mass isn't very low. 20% to 30% shedding is reasonable. When the shedding is higher than 30%, it becomes difficult to explain how the top of the pile could be near the bowtie level, unless the debris in the pit is considered to be loosely compacted.

The collapse duration is relatively insensitive to mass shedding. I've written a Greening type of model that accounts for a constant amount of mass shedding per story impact during crush-down. A total shedding of 30% of the tower mass adds about one second to the collapse duration compared with no shedding. That doesn't put the predicted collapse duration beyond the observed duration.

Hey shagster, welcome. I was curious about your thoughts on the communition of Zone C to Zone B are for WTC 1 and 2 respectively. (not just the concrete, the whole upper mass). Second, what effect does the free standing core have on the amount of mass "shed", and hence the collapse duration, in your model? As I think you are aware, it is still my contention that the lateral forces on the exterior by Zone B preclude it (the exterior) from contributing to the available energy of Zones B and C. These two combined would certainly represent much more than 30% of the mass, while still allowing it to remain relatively close to the perimeter.

grmcdorman

21st June 2007, 08:22 AM

Interesting how this thread has evolved from physics from non-experts ... to physics (well, engineering) from experts. :D

And the experts all agree, apparently, on the overall collapse scenario, and are discussing what are, to this layperson, fine details.
:cool:

rwguinn

21st June 2007, 09:27 AM

grmcdorman

21st June 2007, 12:20 PM

Da%n, guys--
we've been discovered!:D"You can run, but you can't hide." :p

shagster

2nd July 2007, 07:00 AM

Hey shagster, welcome. I was curious about your thoughts on the communition of Zone C to Zone B are for WTC 1 and 2 respectively. (not just the concrete, the whole upper mass). Second, what effect does the free standing core have on the amount of mass "shed", and hence the collapse duration, in your model? As I think you are aware, it is still my contention that the lateral forces on the exterior by Zone B preclude it (the exterior) from contributing to the available energy of Zones B and C. These two combined would certainly represent much more than 30% of the mass, while still allowing it to remain relatively close to the perimeter.

I will try to comment on that later. I've been looking at the SAP2000 model lately and have been busy with other projects. I don't mean to ignore anyone's posts.

I'm getting total tower mass values in the range of 335E6 to 353E6 kg based on data in the SAP2000 model of the tower.

From what I've read in NCSTAR 1-2a, NIST used the self-weight feature in SAP2000 to automatically add up all the weight of the core and perimeter columns, spandrels, and the hat truss. They added in other loads such as non-column CDL, SDL, and LL by tacking them to columns as joint loads. By adding up these two classes of weights (self-weight and joint loads), the total tower weight can be determined from the SAP2000 model. Those weights can be extracted from the SAP2000 model without actually running an analysis.

I have to go through this more carefully to see if I'm misunderstanding anything.

I will try to run an analysis in SAP2000 and see what the loads were on all the columns at the base of the tower. This should also agree with a total mass of about 335 to 353E6 kg. I already ran one of the wind loading conditions sucessfully in SAP2000 and saw how the tower bends in the wind.

The NIST SAP2000 global model is detailed. There are tens of thousands of elements. The joint load table alone has about 269,000 rows of data.

R.Mackey

2nd July 2007, 09:10 AM

A belated welcome to you, too, shagster.

What you have above looks correct. Question: Does this mass include the basement? The foundation? From representations of the model in NIST NCSTAR1-2 it appears that the SAP2000 model does include the structure in the basement, but does not include the foundation, treating it as a fixed boundary condition. But it's hard to say without looking at the model itself...

shagster

2nd July 2007, 04:57 PM

I've run the SAP2000 model. The model that shows up in SAP2000 doesn't show the foundation. It shows a fixed boundary condition at the very bottom of the tower. It includes the below-grade stories (sub-levels).

shagster

2nd July 2007, 05:06 PM

I added up all of the joint loads in the data table for WTC2. These are the loads that are not self-weights that NIST added in as joint loads. They are labeled in the data table as CDL, SDL, and LL and appear in the F3 column. For WTC2, the total came up to 281E6 kg. The total tower weight has to be more than this since this value doesn't include the weight of the core and perimeter columns and the hat truss components, which NIST decided would be taken care of by the SAP2000 self-weight feature. This feature automatically adds up the weight of all these components. The self-weight plus the joint loads should give the total load from what I understand.

shagster

3rd July 2007, 03:43 AM

Here is a summary of the gravity joint loads, self-weights, and their sums. Someone else familiar with SAP2000 should try this. I will try to run an analysis with no wind loading and measure the total of the loads on all the columns at the base of the towers. It should give the same results as what was derived from the data tables.

WTC1 tower mass:

WTC1 joint loads: 279.2E6 kg
WTC1 self-weight: 72.1E6 kg
WTC1 total: 351.3E6 kg

WTC2 tower mass:

WTC2 joint loads: 280.6E6 kg
WTC2 self-weight: 65.8E6 kg
WTC2 total: 280.6+65.8 = 346.4E6 kg

shagster

4th July 2007, 07:36 AM

The correct mass and proper sequence of "crush up" first makes a huge difference in the timings. If Bazant is wrong about the amount of ejected debris this also makes a significant difference. I still think 20% is very low. I think we will find that the gravity driven collapse time will end up being around 20 seconds.

Based on the height of the rubble pile within the tower footprint and assuming that the stories were squashed down to about 10 to 15% of their original height, a total mass shedding of 20% of the tower mass isn't very low. 20% to 30% is reasonable. When the shedding is higher than 30%, it becomes difficult to explain how the top of the pile could be near the bowtie level, unless the debris in the pit is considered to be loosely compacted.

The collapse duration is relatively insensitive to mass shedding. I've written a Greening type of model that accounts for a constant amount of mass shedding per story impact during crush-down. A total shedding of 30% of the tower mass adds about one second to the collapse duration compared with no shedding, so the increase in collapse duration isn't huge. 30% doesn't put the predicted collapse duration beyond the observed duration.

shagster

4th July 2007, 07:42 AM

In his zest to try to obtain a 20-second collapse duration and insinuate an explosives conspiracy, Hoffman has stated that a mass shedding per impact of 'only 6%' of the upper block mass is needed. Consider how much shedding that is for the above-grade stories. For WTC1, 6% of the 14 stories of the upper block is 0.84 of a story mass. For 110 impacts, the total shedding would be 110*0.84 or 92 stories. That leaves only 18 stories for the pit. That's not realistic considering the pile height in the pit was up to the bowtie level and the way the materials were squashed in the pit to the point of looking like a meteorite.

Hoffman's figure of 'only 6%' is even more problematic for WTC2. 6% of 29 stories in the upper block is 1.74 stories. That means 1.74 stories would be shed each impact. For 110 impacts, the total shed mass would be 1.74*110 = 191 stories, which is more stories than the tower had. All of the mass of an impacted story would need to be shed plus an additional 0.74 stories. That 0.74 story worth of mass would have to come from the next intact story of the lower section that hasn't yet been impacted or it would have to be shed from the upper block somehow.

shagster

4th July 2007, 08:13 AM

GregoryUrich

4th July 2007, 04:44 PM

I'm getting about the same values in my model as Hoffman's java model for the increase in collapse duration as a result of shedding. However, I don't agree with his claim about 6% of the upper block mass shed per impact since it doesn't agree with the height of the rubble pile.

A more realistic total shedding of 30% of the tower mass amounts to 30% of a story mass shed per impact. In terms of upper block mass for WTC1, 30% of a story mass is 0.3/14 = 0.02 or 2% of the upper block mass shed per impact. For WTC2 it would be 1% of the upper block mass shed per impact.

In the videos, at least for wtc1 it appears that ramps up during the first part of the collapse and that there is a huge increase in sheading around the mechanical floors (79-81). After that is is really hard to see what is happening.

Are you using "crush up" first? (I.e. the top part collapses from the bottom up onto the bottom part and then the bottom part collapses top down.)

shagster

8th July 2007, 04:53 PM

In the videos, at least for wtc1 it appears that ramps up during the first part of the collapse and that there is a huge increase in sheading around the mechanical floors (79-81). After that is is really hard to see what is happening.

Are you using "crush up" first? (I.e. the top part collapses from the bottom up onto the bottom part and then the bottom part collapses top down.)

I'm using crush-down of the lower section followed by crush-up of the upper block.

The overall mass shedding percentage needs to agree with the height of the rubble pile within the tower footprint. There's no other way around that. Claims of very high shedding don't agree with the observed height of the rubble pile.

shagster

8th July 2007, 05:09 PM

Sole crush-up at the start of collapse wouldn't be able to continue on its own for more than a few impacts without crush-down. A pile of debris would build up at the stationary front at the damaged aircraft impact region. The floors between the core and perimeter could support only a couple stories worth of static mass. They needed to be reinforced to hold the batteries for the UPS system at Fuji and a safe. They wouldn't be able to support a growing pile of mass at a stationary front and would collapse after a couple impacts, which would start crush-down.

GregoryUrich

8th July 2007, 06:08 PM

Take a look at Gordon Ross's presentation (http://video.google.com/videoplay?docid=4801566025292753615&hl=en) regarding crush down vs crush up. It is obvious that crush up starts before crush down and that crush up finishes early in the collapse.

Regarding mass sheading, are you referring to the height of the rubble pile within the foot print?

shagster

8th July 2007, 08:31 PM

If you draw the lines in the wrong places, then it can give the appearance that there was more crush-up at the start of collapse than what actually occurred. For example, drawing a line about five stories below the point where the collapse actually initiated and claiming that's where the collapse started.

Crush-up of more than a couple stories without crush-down can't occur for a structure like the towers had. The top-most floor of the lower section will fail when a couple stories worth of mass accumulates there. Drawing lines in the wrong places doesn't change that.

Videos show that some sections of perimeter wall lingered for up to 20 stories after the collapse front had passed. That can give the impression that crush-down wasn't occurring when it was.

Regarding shedding, I'm referring to the height of the rubble pile within the tower footprint at the end of collapse. I define shedding as mass that went outside the tower footprint during collapse.

There may have been some additional 'shedding' when the collapse front finally hit the ground and if some of the mass of the pile that was within the tower footprint got rammed outside the footprint near the end of the collapse at or near the ground level. That would reduce the rubble pile height and give the impression that more shedding had occurred story-by-story throughout the collapse than what actually occurred.

Furcifer

8th July 2007, 09:37 PM

Shagster: Just out of curiousity, based on what you have defined as "shedding" do you agree or disagree with the assertion that virtually all of the exterior mass was shed during the collapse? I am under the assumption that the lateral forces on the exterior would exclude it from contributing to the collapse front, but this does not appear to be supported but the most recent papers I have read.

shagster

12th July 2007, 02:37 PM

From the aerial photos there were many exterior panels outside the footprint. It appeared that most of the panels went outside the footprint but I don't have any way of quantifying that.

I wouldn't expect the shedding of the exterior panels alone to have a large effect on collapse rate, especially in the upper half of the tower where the column wall thickness was thin.

The exterior columns were on the order of 0.25 inch thick in the aircraft impact regions and higher. I calculate the mass of the exterior columns and spandrels as 8.8E4 kg per story near the 96th story. From NIST 1-6d, the mass of an office story was about 1.6E6 kg. The average mass per story in the part of the tower above the aircraft impact region was higher than this due to the extra mass of the mechanical floors and hat truss (in the range of 2.1 to 2.8E6 kg per story depending on how many stories are averaged for the region above the aircraft impact region, anywhere from 14 to 29 stories).

Ratio of mass of exterior panels in a story to the total mass of an office story near the 96th story:

8.8E4 kg / 1.6E6 kg = 0.055 = 5.5 %

The exterior panels were a small fraction of a story mass in the upper region of the towers.

A Greening type model modified to include the effects of mass shedding shows that about 30% of a story mass needs to be shed to increase the duration of the collapse by about a second. Shedding all the perimeter columns in the aircraft impact regions would be about 5.5% of a story mass, which in itself would increase the collapse duration by much less than a second.

The columns in lower regions were thicker and were a higher percentage of a story mass. Then again, the collapse front had picked up much KE by the time it reached the lower regions of the towers. So the effect of a larger percentage of exterior panel mass being shed later in the collapse would be expected to not have as large an effect on slowing the collapse front as when the front was moving much more slowly and with less accumulated mass.

Furcifer

12th July 2007, 02:57 PM

From the aerial photos there were many exterior panels outside the footprint. It appeared that most of the panels went outside the footprint but I don't have any way of quantifying that.

I wouldn't expect the shedding of the exterior panels alone to have a large effect on collapse rate, especially in the upper half of the tower where the column wall thickness was thin.

The exterior columns were on the order of 0.25 inch thick in the aircraft impact regions and higher. I calculate the mass of the exterior columns and spandrels as 8.8E4 kg per story near the 96th story. From NIST 1-6d, the mass of an office story was about 1.6E6 kg. The average mass per story in the part of the tower above the aircraft impact region was higher than this due to the extra mass of the mechanical floors and hat truss (in the range of 2.1 to 2.8E6 kg per story depending on how many stories are averaged for the region above the aircraft impact region, anywhere from 14 to 29 stories).

Ratio of mass of exterior panels in a story to the total mass of an office story near the 96th story:

8.8E4 kg / 1.6E6 kg = 0.055 = 5.5 %

The exterior panels were a small fraction of a story mass in the upper region of the towers.

A Greening type model modified to include the effects of mass shedding shows that about 30% of a story mass needs to be shed to increase the duration of the collapse by about a second. Shedding all the perimeter columns in the aircraft impact regions would be about 5.5% of a story mass, which in itself would increase the collapse duration by much less than a second.

The columns in lower regions were thicker and were a higher percentage of a story mass. Then again, the collapse front had picked up much KE by the time it reached the lower regions of the towers, so the effect of a larger percentage of exterior panel mass being shed later in the collapse would be expected to not have as large an effect on slowing the collapse front as when the front was moving much more slowly and with less accumulated mass.

For me the duration of the collapse appears insignificant in the overall model. There would appear to be at least a 3 second variation in the overall collapse time when you consider both the video evidence and the seismic. As you have noted the mass distribution does little to put this outside the realm of possibility, a crushing blow to the CT controlled demolition theory once again (pun intended). I just feel it represents a serious distraction from validity of the new Bazant et. al. paper, rainsing concerns with the calculation of mass in the crushing front. When I combine this with the video evidence of the free standing core I see an opportunity for the CT rebuttal and subsequent dismissal of the global collapse theory as per Bazant. Just an observation.

GregoryUrich

12th July 2007, 04:55 PM

How did I miss this?

NISTNCSTAR1 p32 (http://wtc.nist.gov/NISTNCSTAR1CollapseofTowers.pdf)

Go figure.

shagster

15th July 2007, 05:27 PM

That's the 'Final Report on the Collapse of the World Trade Center Towers'.

On p67 and p87 of that same report it says that roughly 200,000 tons of steel were used in the construction of the two towers.

shagster

15th July 2007, 05:42 PM

shagster

15th July 2007, 05:55 PM

shagster

15th July 2007, 05:57 PM

I tend to list everything in terms of kg. To get the weight, multiply by 9.81 m/s2.

GregoryUrich

15th July 2007, 06:01 PM

100,000 tons of steel per tower would be 91E6 kg. The self-weights in the SAP2000 model of WTC2 were 65.8E6 kg. That includes the steel components of the frame, such as the core and perimeter columns, spandrels, and hat truss. It doesn't include the steel in the floors from what I understand from the NIST report. 100,000 tons or 91E6 kg of steel total per tower is reasonable.

I've done my own half-assed estimate and I have seen another detailed calculation on the net that concur with the 100,000 tons of steel. This includes all structural steel and as well the foundation grillages, floor panels and rebar.

I interpret the final report as they are referring to the service weight but whether that only includes the portion above ground is unclear.

I think the steel and concrete masses are the easiest to validate and are correct in my article (http://www.journalof911studies.com/letters/wtc_mass_and_energy.pdf). I'm still reworking the SDLs but the SLLs are at least in line with research and NIST. The SLL detail however must be reworked to take account for empty space in the core.

My best guess at this point is that it would be difficult to justify a service weight greater the 300,000,000 Kg per tower.

I'm using weight and mass interchangeably. I don't think anyone is using Newtons.

shagster

15th July 2007, 06:06 PM

Whatever the total tower weight, it needs to agree with the observed sway periods that were measured in the 80s and 90s and just after the aircraft impact of WTC2.

The stiffness of the towers was established mainly by truss action of the perimeter walls. There shouldn't be too much contention there since the dimensions of the columns and spandrels were well documented. The non-frame mass is where there is more uncertainty. The SAP2000 model can't be far off in terms of the total mass, since it predicted nearly the same sway periods as those that were observed.

Newtons Bit

15th July 2007, 06:21 PM

I'm using weight and mass interchangeably. I don't think anyone is using Newtons.

No need to get personal...

:D :D :D

GregoryUrich

15th July 2007, 06:30 PM

No need to get personal...

:D :D :D

No offense intended Mr. Bit. :D

shagster

15th July 2007, 07:08 PM

Here's a still from the SAP2000 WTC2 model that I ran. It shows non-frame loads that were tacked on to the perimeter columns. The trident level is evident about a third of the way down from the top of the pic where 3 columns are seen converging to one.

These are non-self-weight loads. There's a very long table that contains all of these loads. They take into account the non-frame CDL and the SDL and LL.

http://i134.photobucket.com/albums/q91/shagster31/SAP2000/sap1a400.jpg

shagster

15th July 2007, 07:14 PM

This is the table from SAP2000 that I ran showing the self-weights for WTC1. These are the frame components that SAP2000 added up automatically (core and perimeter columns, spandrels, hat truss). NIST had SAP2000 add these weights up itself but NIST inserted the weights of components other than these by tacking them onto columns. Those non-self-weight loads appear in another table.

http://i134.photobucket.com/albums/q91/shagster31/SAP2000/wtcsteel1.jpg

GregoryUrich

16th July 2007, 06:13 PM

The self-weights in the SAP2000 model are divided into two weights, the frame weights and another weight referred to as 'area load'. I don't know the full details of what area load refers to.

For WTC1 the sum of the frame weight 54.3E6 kg and the area load 17.8E6 kg is 72.1E6 kg. 72.1E6 kg is the total self-weight for WTC1.

For WTC2 the total self-weight is 65.8E6 kg.

That self-weight is confusing me.

Based on NIST's published numbers including the design documents:

Steel in columns = 51.5E6 kg
Steel in floors (including horizontal members) = 38.7E6 kg

The area load can't include the concrete because that is more than 100E6 kg by itself.

shagster

16th July 2007, 08:25 PM

The self-weight didn't include the concrete. It didn't include any components between the core and perimeter or components within the core from what I understand from NIST. Those loads were added by tacking them onto the columns.

NCSTAR1-2a p68:

http://i134.photobucket.com/albums/q91/shagster31/SAP2000/NCSTAR1-2ap68.jpg

shagster

17th July 2007, 01:37 PM

Based on NIST's published numbers including the design documents:

Steel in columns = 51.5E6 kg
Steel in floors (including horizontal members) = 38.7E6 kg

The total steel mass of the tower frame (not including steel in the floor slabs) in the self-weight table in SAP2000 is 54.2E6 kg for WTC1 and 54.6E6 for WTC2. Those values are similar to the value of 51.5E6 kg for the total column mass of one tower that you stated.

shagster

17th July 2007, 01:45 PM

There are apparently a few exceptions regarding the self-weights in SAP2000 and the concrete. The self-weights in SAP2000 apparently took into account some of the non-frame loads on selected floors such as those associated with the mechanical floors. The self-weights also took into account some of the load associated with the roof and the antenna tower on WTC1.

Looking at the SAP2000 self-weight table in terms of section properties for WTC2 shows that the area load includes some of the load on stories 3, 4, 5, 6, 7, 9, 41 ,42, 43, 75, 76, 77, 107, 108, 109, 110, and the roof. The non-frame mass on all the other stories was taken into account by tacking it to columns as concentrated loads. Those loads appear in a separate load table in SAP2000.

The area loads by object type in the SAP2000 self-weight table for WTC2 have the names CONC and CONC3835, which apparently refers to concrete. The number 3835 in the table may be referring to the compressive strength of the concrete. Only Floors 7 and 107 have the number 3835, which apparently used a different strength of concrete.

Here are screen captures of the last part of the self-weight table by section property in SAP2000 for WTC1 and WTC2. There are 3093 rows in the table for WTC2 accounting for all the different components in the tower. NIST and LERA did an extensive accounting of all the mass in the towers.

WTC1:

http://i134.photobucket.com/albums/q91/shagster31/SAP2000/tables/WTC1excelselfsectionkgsm.jpg

WTC2:

http://i134.photobucket.com/albums/q91/shagster31/SAP2000/tables/WTC2excelselfsecsm.jpg

shagster

17th July 2007, 01:57 PM

Here are screen captures of the Excel files of the self-loads by object type for WTC1 and WTC2 in the SAP2000 model. These are the entire tables. I added the two columns at the far right. One sums up the steel frame self-weights and the other sums up the area self-weights. The very last row in those two columns is the sum of the column. For example, 54.2E6 kg for the frame self-weights and 17.7E6 kg for the area self-weights for WTC1.

Summing the frame and area self weights gives the total self-weights, which appears in row 22, column 3.

WTC1: 54.2 + 17.7 = 71.9E6 kg
WTC2: 54.6 + 11.1 = 65.7E6 kg

http://i134.photobucket.com/albums/q91/shagster31/SAP2000/tables/WTC1excelselfobjectkgms.jpg

http://i134.photobucket.com/albums/q91/shagster31/SAP2000/tables/WTC2excelselfobjectsumkgsm.jpg