What are your favorite 9/11 debunking tactics?

Originally posted by psikeyhackr
All that bitching about my code and now you say you haven't looked at it?

Maybe you should see a psychiatrist.

I've read your code. I haven't checked to make sure your calculations are even correct. Remember, you didn't even post working code at the start.

The program is doing computation on the basis of the Conservation of Momentum and gravitational acceleration. So only the conservation of momentum prevents free fall.

That means it is the relative weights of the masses that affects the collapse time not their absolute value. Since the height is shorter then that should reduce collapse time.

I'll reply to this after I know whether the equations you use are even correct. I'm still not finished with my work related stuff and am probably going to give it up for tonight and see if I can hack up something to reproduce this.

If I keep saying this is grade school physics then how great an expert can I be claiming to be? It looks like the experts need to make this whole business look complicated. My program demonstrates that changing the distribution of mass affects the collapse time. So why haven't all of the experts with degrees been saying that since 2002?

Of course changing the distribution of mass changes the collapse time, but as none of these models represent the actual collapse then comparing them with it is invalid. The 'collapse complete' time is the only real thing we can actually measure, and as the time until completion was much longer than 12 seconds then you disprove nothing.

I know the maintenance levels were 14 feet high, not 12. Since the heights of the levels are in the data file anyone that wants to can change them. That is not the point.

It's not just the height you got wrong, it's the mass and mass distribution. I trust Gregory Urichs work as the details are completely open and public, and I can graph how yours differs from his if you like.

My only point was that the conservation of momentum alone makes the collapse time too long compared to what happened on 9/11. The trivia you are brining up just demonstrates that I did not show how bad the official story really was but you want to use that to discredit me rather than explain the physics better to most people.

I'm working on it, I have a job to do at the same time so I have been spending most of my time just refreshing the board while waiting for compiles to complete. That isn't looking so good now so I will try and produce a post with some code explaining precisely what it does in the next hour or so.

Are you sure you know whose side you are on?

I'm on nobody's side! What is with this obsession of rivalry that seems to pervade discussions here. I argue on my own, on my own understanding of the 'official story'. I don't even correspond with anyone here outside the forum!

Ok so here's some preliminary results. I need to go over my code and double check it (and the floor #s aren't well numbered, I'll amalgamate them shortly)

WTC1 - North Tower - Failure at ceiling of Floor 98
Total time taken: 11.89s, Total energy lost: 1.60GJ
paste2.org...

WTC2 - South Tower - Failure at ceiling of Floor 82
Total time taken: 10.06s, Total energy lost: 1.45GJ
paste2.org...

Bear in mind these are preliminary only and I still need to make the code a bit more attractive and clean it up. It's the work of a couple of hours at max so not quite ready, but my results do differ fairly dramatically to yours. I'll do an analysis and find why soon enough.

edit: The first ones I posted had an internal sign error and a slight positioning error too. I'm a bit more confident in these, and they should be within a small percentage of final values. I've included the energy loss to give a comparison. Even in the case of a 'perfect' collapse like this, the energy expended is still the same as 250Kg of TNT. In the real collapse the energy expended was hugely greater, but the only loss here is in perfect collisions.


edit2: Just for info, any lines that say 'from above', are the top section impacting the rubble zone B, the rest is impacting lower storeys. I'll improve the output formatting soon enough and come up with a nicer way, but I want to fix the code up and publish it. It's very annotated with all the equations laid out so people can double check

Originally posted by psikeyhackr

All that bitching about my code and now you say you haven't looked at it?

Maybe you should see a psychiatrist.

Would you mind terribly explaining how writing a program and belittling people who belittle your program has anything even remotely to do with the topic of "what are your favorite 9/11 debunking tactics"?

Or do you think the TOS applies to everyone else but you?

Originally posted by exponent
Ok so here's some preliminary results. I need to go over my code and double check it (and the floor #s aren't well numbered, I'll amalgamate them shortly)

WTC1 - North Tower - Failure at ceiling of Floor 98
Total time taken: 11.89s, Total energy lost: 1.60GJ
paste2.org...

Bear in mind these are preliminary only and I still need to make the code a bit more attractive and clean it up. It's the work of a couple of hours at max so not quite ready, but my results do differ fairly dramatically to yours. I'll do an analysis and find why soon enough.

edit: The first ones I posted had an internal sign error and a slight positioning error too. I'm a bit more confident in these, and they should be within a small percentage of final values. I've included the energy loss to give a comparison. Even in the case of a 'perfect' collapse like this, the energy expended is still the same as 250Kg of TNT. In the real collapse the energy expended was hugely greater, but the only loss here is in perfect collisions.


edit2: Just for info, any lines that say 'from above', are the top section impacting the rubble zone B, the rest is impacting lower storeys. I'll improve the output formatting soon enough and come up with a nicer way, but I want to fix the code up and publish it. It's very annotated with all the equations laid out so people can double check

It looks like you are dropping 12 stories instead of my dropping 14. I don't know what you are using for masses and heights.

You got 11.9 seconds for the north tower versus my 12.54 but you call that "FAIRLY DRAMATIC"

We are talking about a collapse limited by nothing but the Conservation of Momentum. Yet we are both getting numbers slightly higher than what has been claimed for the actual building. Breaking connections and bending steel would have to slow a real top down gravitational collapse further by a significant amount.

So you would have to decide what to add to your number to get some idea what a real gravitational collapse should have taken.

I am not claiming the numbers I got are the times the real building should have taken. I am using this program to show that the WTC came down impossibly fast.

Are you refusing to THINK about the significance of your own simulation? And then you want to accuse ME of rivalry. So why are you dropping 12 floors. Most people say 14 or 15 came down on the north tower. And I don't do the south tower at all because the significant aspect of that event was the top 29 stories tilting at 22+ degrees and then our great physicists never talk about the location of the center of mass and neither does the NIST in their 10,000 pages.

What did you use for distribution of mass data?

Of course changing the distribution of mass changes the collapse time, but as none of these models represent the actual collapse then comparing them with it is invalid. The 'collapse complete' time is the only real thing we can actually measure, and as the time until completion was much longer than 12 seconds then you disprove nothing.

What do you mean by "collapse complete" time?

For the north tower we have figures from 9 to 11 seconds for the collapse of the floors and perimeter but those figures are somewhat uncertain because of the cloud of dust. Then we have 25 seconds for the remains of the core referred to as "The Spire".

Now if the Conservation of Momentum ALONE gives us a 12 second figure and WE KNOW that breaking connections and bending steel would have to more than double the collapse time then why can't we conclude that even 25 seconds for the north tower was IMPOSSIBLE for a gravitational induced collapse caused by airliner impact and fire? And then the NIST does not provide steel and concrete distribution data after admitting it was necessary to do the impact analysis.

The energy expended was only hugely greater if you ASSUME the falling mass could destroy all of the supports and ASSUME that nothing else was responsible. So if you ASSUME the gravitational collapse could break all of those connections without slowing down then you need to compute how much energy was required to break them.

As the collapse progressed, dust and debris could be seen shooting out of the windows several floors below the advancing destruction, caused by the sudden rush of air from the upper levels. The first fragments of the outer walls of the collapsed North Tower struck the ground 11 seconds after the collapse started, and parts of the South Tower after 9 seconds. The lower portions of both buildings' cores (60 stories of WTC 1 and 40 stories of WTC 2) remained standing for up to 25 seconds after the start of the initial collapse before they too collapsed.

en.wikipedia.org...

I built a physical model where the supports had to be crushed for the masses to come down. IT ARRESTED! The energy to destroy the supports has to come from somewhere and the only place is the Kinetic Energy of the falling mass so it slows down which would increase the collapse time if it does not arrest completely. So any collapse limited only by the Conservation of Momentum Provides an impossible minimum collapse time. So how can some numbers for the real thing be less?

psik

Originally posted by psikeyhackr
It looks like you are dropping 12 stories instead of my dropping 14. I don't know what you are using for masses and heights.

Dropping from ceiling of floor 96 yields:
Total time taken: 11.64s, Total energy lost: 1.59GJ

You got 11.9 seconds for the north tower versus my 12.54 but you call that "FAIRLY DRAMATIC"

It was actually a bit different, but I definitely had some early errors leading to some inconsistency.

We are talking about a collapse limited by nothing but the Conservation of Momentum. Yet we are both getting numbers slightly higher than what has been claimed for the actual building. Breaking connections and bending steel would have to slow a real top down gravitational collapse further by a significant amount.

I've already explained why this is wrong, but maybe you missed it. What you have done here is give the minimum momentum to the upper block. At the point of failure every floor there falls apart and falls independently onto the much stronger lower section.

In no way have you created a lower bound here, and this is just another in what is quickly becoming a library of errors.

I am not claiming the numbers I got are the times the real building should have taken. I am using this program to show that the WTC came down impossibly fast.

Are you refusing to THINK about the significance of your own simulation? And then you want to accuse ME of rivalry. So why are you dropping 12 floors. Most people say 14 or 15 came down on the north tower. And I don't do the south tower at all because the significant aspect of that event was the top 29 stories tilting at 22+ degrees and then our great physicists never talk about the location of the center of mass and neither does the NIST in their 10,000 pages.

More utter nonsense. You don't even understand the model you created. You talk of needing accurate data, but you don't even know where information you need is, your models don't match up with reality, and your calculations as a result are severely flawed.

Why don't you step back and look at the fact that for years you've been demanding attention and verification, and now with the tiniest bit of peer review your entire argument has come crashing down. You've relied on data far less accurate than that you have criticised, and used that to try and prove a case based on falsehoods.

What did you use for distribution of mass data?

For about the 50th time. Gregory Urich's paper. I manually calculated and extracted floor heights from original design drawings and the released blueprints, then used his floor masses.

What do you mean by "collapse complete" time?

For the north tower we have figures from 9 to 11 seconds for the collapse of the floors and perimeter but those figures are somewhat uncertain because of the cloud of dust. Then we have 25 seconds for the remains of the core referred to as "The Spire".

I mean that because you have weakened the upper section to the limit possible in this model, it is only sufficient for telling us the fastest possible time the collapse could have finished in its entirety. That is after all the result of both of our models, the top section collapses in upon itself before reaching the bottom. This is the lower bound for collapse completion, not a bound for debris hitting the ground.

The energy expended was only hugely greater if you ASSUME the falling mass could destroy all of the supports and ASSUME that nothing else was responsible. So if you ASSUME the gravitational collapse could break all of those connections without slowing down then you need to compute how much energy was required to break them.

Bazant has already done this. Repeatedly. He addressed it in a much more professional and accurate manner than I ever will be able to. If you want some simple differentiation or partial integration I might be your man. Bazant's level of skill I will probably not reach.

Incidentally, do you notice that within the data, the proof of Bazant's 'B' zone of compacted rubble is immediately supported? Look at the values for absorbed energy as the floors collapse together. Even this simple model proves something that truthers have been denying for close to 6 years now.

I wonder if you can even see it.

Originally posted by exponent
Bazant has already done this. Repeatedly. He addressed it in a much more professional and accurate manner than I ever will be able to. If you want some simple differentiation or partial integration I might be your man. Bazant's level of skill I will probably not reach.

Incidentally, do you notice that within the data, the proof of Bazant's 'B' zone of compacted rubble is immediately supported? Look at the values for absorbed energy as the floors collapse together. Even this simple model proves something that truthers have been denying for close to 6 years now.

I wonder if you can even see it.

I see. We are all supposed to become Bazant worshippers And believe his math because you do.

There is just a little matter of Newton's Third Law which Bazant seems to violate by having the top block of the north tower remain intact while crushing everything below.

So where is your code and data file?

psik

Originally posted by psikeyhackr
I see. We are all supposed to become Bazant worshippers And believe his math because you do.

Oh no, you can believe his maths because his papers are reviewed by industry experts and get posted to places like Journal of Engineering Mechanics: www.asce.org...

So where is your code and data file?

I'm still cleaning it up. I'm going to add a couple more failure modes and remove some duplications. Why don't you work on your code at the same time and then once we both have clean, working code, we can come to some agreement about what can be predicted and extrapolated.

Note that I wrote my code in a couple of hours and that includes most of the research to find the floor heights etc. You should be able to reproduce it without me if needs be. I will post it in the next day or so though.

Originally posted by psikeyhackr
I see. We are all supposed to become Bazant worshippers And believe his math because you do.

So where is your code and data file?

psik

An ad hominem against Bazant in order to avoid actually critiquing the work is still an ad hominem, and holds no real argumentative weight.

It's not about idol worship. It's about tests and verifiable math. If you can prove that there are serious flaws in Bazant's math, feel free to post it or submit a paper to the journal critiquing it. Otherwise, you're just blowing hot steam, just angry that someone disagrees with you.

reply to post by Varemia


I'm not going to say it's a huge "flaw" - his work seems to be well thought out and some of his equations just a tad beyond me at this point - but he estimates a uniform stiffness of the columns for each floor at ~71 GN/m with an "approximate design of column cross-sections." He does acknowledge that it should vary and that he's working with a lack of precise data. Just how reliable is putting each column at equal elasticity? I'm not sure, but it's pretty much agreed that the columns were thicker at the bottom, no? That's a big part of his math that led him to the conclusion that even with cold columns the building would have collapsed only 6% faster than free fall speeds...

In fact, a lot of his measurements are "approximate due to lack of information."

Well, I am looking at the "simplified approximate analysis" from 2002. Do you have more resources where I can find more of his work?

reply to post by jlm912


This is one of his more recent papers, quantifying the resistive forces and addressing some concerns:

www.civil.northwestern.edu...&%20Did%20Not%20Cause%20It.pdf

He also directly replies to some criticisms here:

www.civil.northwestern.edu...

There's a few more incidental papers here and there, but in general you need to be an engineer to even begin to understand what is going on with these equations. I admit that most of them are above me at least in the subtle aspects, if not the major ones as well.

Apparently we are supposed to wander into the fantasyland of Bazantianism.

bogus911science.wordpress.com...

www.911blogger.com...

The top fraction of the north tower could supposedly crush about eight times its on height even though all equal sized portions below had to be heavier and stronger than the falling portion.

So we are supposed to keep arguing even though exponent computed an 11+ second collapse time which involved no bending or breakage of components that had to be strong enough to hold up the building. So apparently the energy required to eliminate those supports had to come out of some magic hole and does not need to be explained.

So where is your code and data?

psik

If there is any question about columns getting larger at the bottom all the info is here...

wtcmodel.wikidot.com...

The core columns tapered considerably.

This is one column at the bottom...



The same column at the top...



As you can see it tapered quite considerably. That means the core columns were collapsing down into a larger and larger path of most resistance, which is simply illogical. The collapsing of floors should not have effected the core. Anyone with common sense can see the core must have failed, not the trusses.

Originally posted by ANOK
If there is any question about columns getting larger at the bottom all the info is here...

wtcmodel.wikidot.com...

The core columns tapered considerably.

This is one column at the bottom...



The same column at the top...



As you can see it tapered quite considerably. That means the core columns were collapsing down into a larger and larger path of most resistance, which is simply illogical. The collapsing of floors should not have effected the core. Anyone with common sense can see the core must have failed, not the trusses.

So how about those truss seats did they get stronger in the lower parts of the building ?

After all none of us Debunkers are saying any columns had to be crushed after collapse initiation. Only Truthers say columns had to be crushed.

Originally posted by ANOK
If there is any question about columns getting larger at the bottom all the info is here...

wtcmodel.wikidot.com...

The core columns tapered considerably.

But what happened with the horizontal beams in the core? The length of horizontal beams is about 2 1/2 times as the vertical columns in the core.

psik

Originally posted by waypastvne

So how about those truss seats did they get stronger in the lower parts of the building ?

I would imagine the mechanical floors had stronger truss seats, but I can't say for sure.

After all none of us Debunkers are saying any columns had to be crushed after collapse initiation. Only Truthers say columns had to be crushed.

So what did the core do then? Crushed or just broken up, it all takes energy that simply was not available.

I have never claimed the core 'crushed' though. It is you who is claiming sagging trusses could pull in columns, and then collapsing floors caused the core to collapse. Problem is as the floors collapsed it would take increasing energy to collapse the core as the cores mass increased. Either the Ke increased, or some other energy took away the resistance. Which is it?

Originally posted by psikeyhackr
But what happened with the horizontal beams in the core? The length of horizontal beams is about 2 1/2 times as the vertical columns in the core.

psik

Good question. Logic would tell me they changed in size also. Why reduce the columns sizes, to reduce weight, and not the cross bracing? Thinner columns would not need the same cross bracing as thicker columns.

Obviously NIST ignored the cross bracing in their analysis.

Originally posted by exponent
reply to post by jlm912

 

This is one of his more recent papers, quantifying the resistive forces and addressing some concerns:

www.civil.northwestern.edu...&%20Did%20Not%20Cause%20It.pdf

He also directly replies to some criticisms here:

www.civil.northwestern.edu...

There's a few more incidental papers here and there, but in general you need to be an engineer to even begin to understand what is going on with these equations. I admit that most of them are above me at least in the subtle aspects, if not the major ones as well.

Your second link contains this paragraph:

The paper appears to justify this collapse mode by making a key assumption that the authors do not support with any explanation or analysis. This key assumption, which is one of what the authors call “reasonable . . . simplifying hypotheses” is that, during the building collapse, “energy is dissipated only at the crushing front
this implies that the blocks in Fig. 2 may be treated as rigid, i.e., the deformations of the blocks away from the crushing front may be neglected . . .” In other words, the paper assumes that Part C of each tower is treated as a rigid block while it crushes down through and destroys the lower structure. Although this assumption may have had the intended effect of simplifying the paper’s collapse analysis, it also rendered the collapse analysis at odds with the reality of the physics at work during the collapse. It should be noted here that no lateral forces are considered in this discussion in accordance with another simplifying assumption made by the paper, namely, that the “only displacements are vertical”
p. 312 of the paper. This simplifying assumption is flawed
e.g., steel members and dust were spread across a wide area surrounding the location where the towers stood but is beyond the scope of this discussion

That is the fundamental Bazant nonsense.

Throw up some fancy complicated math that few people can wade through. Throw Newton's 3rd Law out the window and claim that it is correct. So the mystery is why so many people with degrees who supposedly know physics let this BS go on.

psik

Yeah the biggest flaw of Bazant is he treats the top floors as one solid block, and the lower block as single floors.

So you get the myth that all the top floors put all their force on one floor.

Yes this ignores Newtons 3rd law.

The fact is the force of the upper floors would effect the lowest floor of the top block, as much as the impacted floor of the bottom block. Both floors are crushed, damaged, deformed, whatever you want to call it. The top cannot stay as one block crushing lower floors.

Originally posted by waypastvne

Originally posted by ANOK
If there is any question about columns getting larger at the bottom all the info is here...

wtcmodel.wikidot.com...

The core columns tapered considerably.

This is one column at the bottom...



The same column at the top...



As you can see it tapered quite considerably. That means the core columns were collapsing down into a larger and larger path of most resistance, which is simply illogical. The collapsing of floors should not have effected the core. Anyone with common sense can see the core must have failed, not the trusses.

So how about those truss seats did they get stronger in the lower parts of the building ?

After all none of us Debunkers are saying any columns had to be crushed after collapse initiation. Only Truthers say columns had to be crushed.

Oh yeah, tell that to Bazant.

Abstract: Progressive collapse is a failure mode of great concern for tall buildings, and is also typical of building demolitions. The most infamous paradigm is the collapse of the World Trade Center towers. After reviewing the mechanics of their collapse, the motion during the crushing of one floor
or group of floors and its energetics are analyzed, and a dynamic one-dimensional continuum model of progressive collapse is developed. Rather than using classical homogenization, it is found more effective to characterize the continuum by an energetically equivalent snap-through. The collapse, in which two phases—crush-down followed by crush-up—must be distinguished, is described in each phase by a nonlinear second-order differential equation for the propagation of the crushing front of a compacted block of accreting mass. Expressions for consistent energy potentials are formulated and an exact analytical solution of a special case is given. It is shown that progressive collapse will be triggered if the total
internal energy loss during the crushing of one story
equal to the energy dissipated by the complete crushing and compaction of one story, minus the loss of gravity potential during the crushing of that story exceeds the kinetic energy impacted to that story. Regardless of the load capacity of the columns, there is no way to deny the inevitability of progressive collapse driven by gravity alone if this criterion is satisfied
for the World Trade Center it is satisfied with an order-of-magnitude margin. The parameters are the compaction ratio of a crushed story, the fracture of mass ejected outside the tower perimeter, and the energy dissipation per unit height. The last is the most important, yet the hardest to predict theoretically. It is argued that, using inverse analysis, one could identify these parameters from a precise record of the motion of floors of a collapsing building. Due to a shroud of dust and smoke, the videos of the World Trade Center are only of limited use. I

He has a section on column buckling.

psik

Originally posted by ANOK
Yeah the biggest flaw of Bazant is he treats the top floors as one solid block, and the lower block as single floors.

So you get the myth that all the top floors put all their force on one floor.

Yes this ignores Newtons 3rd law.

No it doesn't. This statement alone indicates you have never had any formal physics or engineering schooling at the appropriate level. Bazant also defeats this criticism completely in one of the papers I linked.

It's nonsense, the fundamental principles and equations used do not allow for 'ignoring Newtons 3rd law'. It is simply not possible to do.

The fact is the force of the upper floors would effect the lowest floor of the top block, as much as the impacted floor of the bottom block. Both floors are crushed, damaged, deformed, whatever you want to call it. The top cannot stay as one block crushing lower floors.

On the contrary, my results on an entirely simple model prove it beyond all doubt. Notice the trends in energy dissipiation between impacts from the top section and impacts towards the lower section.

As the building descends, the forces against the upper section become lower and lower due to the growth of a compacted layer of debris. This is with all upper floors broken from their supports and not interconnected. The worst possible case for collapse speed.

ANOK admit your ignorance, please stop acting as if you are a physics expert, when you've clearly never had the schooling to understand the equations presented to you.