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9/11 Physics from Non-Experts

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%.

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.co...mesg&forum=125&topic_id=159282&mesg_id=159611
 
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.
 
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.
 
For those who can run it, the NIST global model is here.

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!
 
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?
 
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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.
 
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.
 
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.co...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.
 
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.
 
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?
 
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.
 
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?
 
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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
 
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.
 
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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?
 
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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.
 
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.
 

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