Video Nullfies Pancake/CD Theory

Originally posted by Akareyon
And the smaller the effective length - something you do using braces, in case you forgot I made that point already - the smaller that area. Of course it seems I don't make any sense if you misinterpret me on purpose. Or think of the core frame as of a few slender 400 meter columns without any horizontal or diagonal beams and bracings.

The only horizontal braces in the WTC buildings were at floor levels. So every 3.7m. Most buildings have no horizontal bracing halve way floors. For the reason that you are left with so little office space. Better just make the columns stronger so the can have a longer unbraced length.

Did you - or was it exponent - not reply on that occasion, after I have called such a tower a metastable system, that all buildings are in a meta stable state and the only way to stabilize them would be to put all members flat on the ground? Did I not agree? Your argument is invalid.

Meta stable and unstable equilibrium are two different things.

Just a general note, you understanding of concepts in physics is severely lacking. You are wrong many times, even though you are not openly acknowledging it.

You say all buildings are in an unstable equilibrium.

No I don't. Please learn the difference between these basic concepts.

Been there, done that. Do want to know how many words exactly they used to describe the collapse sequence in the "Final Report on the Collapse of the World Trade Center Towers" with the objective No. 1 "Determine why and how WTC 1 and WTC 2 collapsed following the initial impacts of the aircraft" (p. xxix)? And would you like to compare it to the computing power for the FEM of each turbine blade of the aircraft? Just so you get some sort of perspective.

I am talking about the lateral loads. Why do you change the subject completely? Let me guess, because you didn't read the reports, and have no clue whats in them?

I haven't, that is true, and I have corrected myself. Read and understand the AISC document I linked, at least the parts I mentioned. It's all about making a steel frame sound and safe with bracings and connections and calculating momenta and using structural analysis. With all that in place, it is impossible to build a steel frame that progressively telescopes into the basement with hardly any friction forces decelerating the descent.

So because you can not quantify your claim, you just insist it is impossible. I insist you are making things up as you go.

You won't believe or understand this because you prefer blind trust over scrutinizing what you learn, but I'll tell you anyway: when I tried to verify the formula and my allegations and studied yield strengths and stress-strain curves , something bugged me quite a lot so I tried to find a solution. I found it. And shared it or everyone who follows this discussion trying to make up his mind and looking for the truth and good arguments pro and con. And I freely and honestly admitted a mistake so others don't carry it elsewhere. That makes me a better scientist than you, who with every mistake I make rejoices and pretends I couldn't tell the difference between a cow pat and a pizza.

Right now, by the way, I'm reading a 1966 paper on our little subject... hold your breath, dear friend, quotes are coming :-)

No I don't believe you. Because you constantly come to the completely wrong conclusions. Like thinking that critical strength is Fc in Bazants paper. These are really the basics which you fail at. And yes, I only understand the basics. As I am no expert either.

reply to post by -PLB-


Again you are spreading nonsense.

A high rise building will not have unbraced columns, that is just stupid, period.

Lightweight trusses do not brace columns, they would buckle.

Here is a closeup during construction...



Horizontal bracing can clearly be seen.

This pic you can see cross bracing...



And what about this...

Some steel beams in the core were reinforced and strengthened to accommodate heavy live loads, such as large amounts of heavy files that tenants had on their floors.[106]

en.wikipedia.org...

Stop making things up man.

Something I just thought of looking at the floors in that last pic.

What part of the floors was supposed to have sagged? NIST, and NOVA, only showed one truss sagging and breaking the columns.

Obviously one truss would not have done anything, right? The floors themselves were one piece essentially, sitting on numerous trusses that were not directly connected together, only through the core and outer columns.

So to get a whole floor system to drop, vertically, would mean all the trusses would have had to sag at the same time and create the same pull on the columns.

Did the columns get pulled in on all four sides, or just one side? If it was just one side, was it all the trusses on that side, just some of them, just one of them? Did NIST even bother to ask these questions? If it was not all of them then how did the floor drop vertically? If it was all of them then why is that not obvious in videos?

If you look at the collapses you see no sign of any floors dropping inside the building. The notion that dropping floors would bring the core down with them, and eject the outer columns outwards is just complete nonsense in light of the way the structure was designed.

It's a solid heavy steel frame, with lightweight trusses suspended between the core, which took most of the vertical load, and mesh box columns that held the lateral load (wind), and some of the vertical load. The core and the outer columns were tied at the hat truss and firmly embedded in the ground. That frame was designed to hold the floors, with an FoS of 4-6, meaning if a component needed to hold 1t, and it had an Fos of 4, it could hold 4t. It was designed with confidence that the component could hold 4x the load that it needed to during it's service lifetime.

Why is that important? PLB? Genradik? Anyone?

Because it would mean the sagging trusses would somehow have to have a load increase AT LEAST 4x what it was designed to hold in order to fail. That is not going to happen just because it sags from heat.

And it still isn't going to pull in the columns, because the connections, or the truss itself would fail first. Why anyone would need that explaining to them is beyond my intellectual capacity to understand.



Seriously?

Originally posted by -PLB-
Meta stable and unstable equilibrium are two different things.

I know. And both can be quantified. You are saying all buildings are not just metastable, but in an unstable equilibrium - mechanisms just waiting to go off.

Just a general note, you understanding of concepts in physics is severely lacking. You are wrong many times, even though you are not openly acknowledging it.

You better have some evidence for such an accusation.

You say all buildings are in an unstable equilibrium.

No I don't. Please learn the difference between these basic concepts.

Yes you do if you say a deviation < 0.2% from the default state inevitably causes a complete adiabatic state change.

I am talking about the lateral loads. Why do you change the subject completely? Let me guess, because you didn't read the reports, and have no clue whats in them?

Yes, you are completely right, so I would be glad if you could point me to the part I missed where it explains how a robust steel frame secured against sidesway and P-Δ effects can have a m*g > F_c.

So because you can not quantify your claim, you just insist it is impossible. I insist you are making things up as you go.

Yes, you are completely right, I cannot quantify my claim, but I have learned something new. Fasten your seatbelt, dear friend. Frame structures are designed so they are secured against sidesway and the so-called P-Δ effect, that means if there is a lateral displacement because of wind or earthquake and the load on the columns is not axial anymore, the columns still have to remain in their elastic range and not buckle. So how can a structure at the same time be secured against sidesway buckling and the P-Δ effect and yet get the hell buckled out of it when axial, ideal overload (in the "most optimistic scenario") is applied? I found this little gem from 1966: Elastic-plastic load-deflection curve considering second-order effects and instability by D.G. Follett Jr. which discusses unstable equilibrium and other stuff. It shows what engineers had to do when computers were giant, expensive and clumsy machines. It gives you great insight how engineers actually calculate their stuff - they use moment diagrams and stuff like that, that is why you as a layman are so easily bedazzled by Bazants load-displacement curve and why you are convinced that all buildings have a kind of self-destruction mechanism built in.

Follett quotes another paper:

A system is said to be in a state of unstable equilibrium if, for any possible small displacement from the equilibrium configuration, upsetting forces will arise which tend to accelerate the system to depart even further from the equilibrium configuration.

Stephen Harry Crandall and Norman C. Dahl: An Introduction to the Mechanics of Solids p. 407, McGraw-Hill Book Company, Inc., New York, 1959 (there was a 2nd edition of this in 1978 with SI units (with Thomas J. Lardner) and they seem to be widely quoted in engineering literature. I hope that Crandall, Dahl and Larnder are of the sort of authority you require for your "truths", even if Newton and Galileo are not).

And that is exactly what allegedly happened: from a small displacement from the equilibrium configuration arose forces which acceleratend and accelerated and accelerated the system to depart all the way from its equilibrium configuration to a stable configuration where all members are resting flat on the ground. The system was in an unstable equilibrium. Randall & Dahl say it, and you say it but avoid the word and the conclusion like the plague.

I wonder what your excuse will be this time.

reply to post by ANOK


All your questions are answered in extremely high detail in the NIST report. The report you never read.

reply to post by Akareyon


The twin towers were not in an unstable equalibrium. Im am not going to discuss any further before you understand that.

Stephen Harry Crandall and Norman C. Dahl: An Introduction to the Mechanics of Solids, p. 407, McGraw-Hill Book Company, Inc., New York, 1959
A system is said to be in a state of unstable equilibrium if, for any possible small displacement from the equilibrium configuration, upsetting forces will arise which tend to accelerate the system to depart even further from the equilibrium configuration.

Zdeněk Pavel Bažant and Mathieu Verdure: Mechanics Of Progressive Collapse, 2007, p. 2
[...] the tower was doomed once the top part of the tower dropped through the height of one story (or even 0.5 m)

Originally posted by -PLB-
The twin towers were not in an unstable equalibrium.

Case closed.

reply to post by Akareyon


Sigh.... Only after a plane had crashed into the towers, causing fires that weakened the steel columns, causing trusses to sag and put a pulling force on the columns, only then for an infinitesimal time, the towers were in a state of unstable equilibrium. Only for that specific moment in time

any possible small displacement from the equilibrium configuration, upsetting forces will arise which tend to accelerate the system to depart even further from the equilibrium configuration

ANOK, if you are reading, notice the any possible small displacement part.

When all that did not happen, the towers were not in an unstable equilibrium.

If you are going to deny this, then whatever, I am done with you like I am done with ANOK. At least for now.

reply to post by -PLB-

You're trying hard, but it will never be enough. You're back to the planes, which crashed into the top floors, which the towers survived, but resulted in fire, which resulted in the whole -- up to that point intact (NIST, before you ask) -- structure underneath collapsing under the force of the top floors dropping on it.

You're trapped between Bazant and Crandall/Dahl. The system already IS in unstable equilibrium when a small displacement causes acceleration. It was in equilibrium, but the equilibrium was unstable. A small displacement - that of the top floors - caused acceleration of the whole structure. "Small" is not quantified here, but the stability of the equilibrium can be quantified. E_kin = 0.5m*58,000t*9.81m/s² = 284,490,000 J = 0.03% of the total potential energy of the structure. Does 0.03% count as small?

Let us compute the Reyonolds number for the flow of the top through the rest of the tower, shall we?

reply to post by Akareyon


Nope, you still don't understand what an unstable equilibrium is. Your nensensical calculations show that. Try harder.

reply to post by -PLB-

So you have to resort to claiming that I'm such an idiot that I don't understand what an unstable equilibrium is to solve the dilemma?

Graham's Hierarchy of Disagreement lists ad hominem as the second worst type of argument in a disagreement.

Source

And what is so nonsensical about putting the input energy in relation to the output energy? That it brings matters to a head, showing how ridiculous the official story about self-decomposing skyscrapers really is?

Originally posted by Akareyon
So you have to resort to claiming that I'm such an idiot that I don't understand what an unstable equilibrium is to solve the dilemma?

You are not an idiot for not understanding it. The problem is that you don't put any effort into understanding it.

A small hint, a building in unstable equilibrium requires an infinitesimal displacement in order to cause global collapse. Even touching it with your finger tip would cause collapse. That is the definition of unstable equilibrium.

And what is so nonsensical about putting the input energy in relation to the output energy? That it brings matters to a head, showing how ridiculous the official story about self-decomposing skyscrapers really is?

For starters, you are not looking at the building in a static state, but in a state where collapse is already initiated. Its that initiation part where you fail. That is what unstable equilibrium is about, even the smallest displacement imaginable results in global collapse. Crashing planes and damage due to subsequent fires hardly fall in that category. In fact, the fires changed the system. And like I already explained, at one point, the building reached a state of unstable equilibrium, and collapsed. After that you have a collapsing building. Which isn't in an unstable equilibrium at all. And that is what you are looking at with your nonsensical calculations.

Thats not the only thing that is wrong, but its a start.

reply to post by -PLB-

In fact, the fires changed the system

If that's true, wouldn't that only pertain to the area affected by the fire? What changed the system in the other 90 undamaged floors?

Originally posted by Flatcoat

If that's true, wouldn't that only pertain to the area affected by the fire? What changed the system in the other 90 undamaged floors?

The top section falling on them.

Originally posted by -PLB-
a building in unstable equilibrium requires an infinitesimal displacement in order to cause global collapse. Even touching it with your finger tip would cause collapse. That is the definition of unstable equilibrium.

The damage done by the planes alone did not cause progressive collapse. The additional damage done by the fires did the rest. Very slowly, it put the building in an unstable equilibrium. It was a matter of centidegrees Celsius, micrometers, nanonewtons or the touch with a finger tip that decided if the whole undamaged tower structure underneath the impact zone would collapse now or a femtosecond later or earlier or never at all. All criteria for an unstable equilibrium are met. Throwing all the 500.000 tons of stuff into all four directions of the wind was now the new path of least resistance to go for the structure until the new equilibrium state - flat on the ground -.was reached a few seconds later. Which part again was it I did not understand?

And like I already explained, at one point, the building reached a state of unstable equilibrium, and collapsed. After that you have a collapsing building. Which isn't in an unstable equilibrium at all. And that is what you are looking at with your nonsensical calculations.

No, I'm looking at the energy conversion efficiency of the tower's mechanism. And it's pretty good, at least for a few seconds in each. A small input energy triggered a huge energy conversion. Give me examples for other things that undergo a huge energetic state change triggered by a small input energy. How many can you think of? Here are some:

1. domino chain reactions (if dominos are set up purposefully)
   
2. avalanches
   
3. bombs
   
4. traps
   
5. machines
   
6. WTC twin towers

Now it's your turn to name a few.

Originally posted by Akareyon

Originally posted by -PLB-
a building in unstable equilibrium requires an infinitesimal displacement in order to cause global collapse. Even touching it with your finger tip would cause collapse. That is the definition of unstable equilibrium.

The damage done by the planes alone did not cause progressive collapse. The additional damage done by the fires did the rest. Very slowly, it put the building in an unstable equilibrium. It was a matter of centidegrees Celsius, micrometers, nanonewtons or the touch with a finger tip that decided if the whole undamaged tower structure underneath the impact zone would collapse now or a femtosecond later or earlier or never at all. All criteria for an unstable equilibrium are met. Throwing all the 500.000 tons of stuff into all four directions of the wind was now the new path of least resistance to go for the structure until the new equilibrium state - flat on the ground -.was reached a few seconds later. Which part again was it I did not understand?

And like I already explained, at one point, the building reached a state of unstable equilibrium, and collapsed. After that you have a collapsing building. Which isn't in an unstable equilibrium at all. And that is what you are looking at with your nonsensical calculations.

No, I'm looking at the energy conversion efficiency of the tower's mechanism. And it's pretty good, at least for a few seconds in each. A small input energy triggered a huge energy conversion. Give me examples for other things that undergo a huge energetic state change triggered by a small input energy. How many can you think of? Here are some:

1. domino chain reactions (if dominos are set up purposefully)
   
2. avalanches
   
3. bombs
   
4. traps
   
5. machines
   
6. WTC twin towers

Now it's your turn to name a few.

right on . That has been my argument from the beginning. What on earth could have done it ?

Path of least resistance was one of my arguments that brought me to the conclusion it has to be something VERY exotic.

without explosives ,months of planning,tearing out walls,weaking columns,and making it a shell its hard to make a buildings path of least resistance DOWN. . Let alone turn it to dust

But plb wont listen . I've had this discussion with him before i think.

Eta since we are talking dominos here I decided to with draw my backing of the "magic " theory in place of the "finger of God " theory.

It will make it easier to explain to most of the god fearing world.

Sorry...I'm laughing....but 4 flags shoots your theory right out the window by the intelligence of ATS and the common sense we have.

This was a controlled demolition...they tried to play us like fools, murdered for the ends of powerful people that mean to take America down for that means.

Originally posted by -PLB-

All your questions are answered in extremely high detail in the NIST report. The report you never read.

If I've never read it, then how come I know it better than you do? I mean you insist the towers pancaked when NIST themselves say they don't support that claim. So your arguments don't even come from the NIST report, but third party players like Bazant.

So PLB, why do you not point those answers out then? You have the opportunity, you have all the text space you need, you have a keyboard, and you claim to know the answers, yet for some reason you can't actually type out those answers. Are you completely clueless, or just completely lazy?

Why do you make things up all the time? I don't see the point?

How do sagging trusses pull in columns PLB? As a reminder here is your last attempt to spin it, and my reply that's rips you to shreds...

www.abovetopsecret.com...

And the one to Genradik that's also rips you to shreds...

www.abovetopsecret.com...

Wow at least one time you guys were a little challenging, now it's just too easy.

Originally posted by Akareyon
The damage done by the planes alone did not cause progressive collapse. The additional damage done by the fires did the rest. Very slowly, it put the building in an unstable equilibrium. It was a matter of centidegrees Celsius, micrometers, nanonewtons or the touch with a finger tip that decided if the whole undamaged tower structure underneath the impact zone would collapse now or a femtosecond later or earlier or never at all. All criteria for an unstable equilibrium are met. Throwing all the 500.000 tons of stuff into all four directions of the wind was now the new path of least resistance to go for the structure until the new equilibrium state - flat on the ground -.was reached a few seconds later. Which part again was it I did not understand?

The part where you claim that the towers were in a state of unstable equilibrium even before the planes crashed into them. Thats the part where you completely go wrong.

You are basically repeating exactly what I was saying. As if it was what you meant all along.

No, I'm looking at the energy conversion efficiency of the tower's mechanism. And it's pretty good, at least for a few seconds in each. A small input energy triggered a huge energy conversion. Give me examples for other things that undergo a huge energetic state change triggered by a small input energy. How many can you think of? Here are some:

1. domino chain reactions (if dominos are set up purposefully)
   
2. avalanches
   
3. bombs
   
4. traps
   
5. machines
   
6. WTC twin towers

Now it's your turn to name a few.

*All other buildings.

We already discussed this. Its why controlled demolition works. Thats when you came with your woo argument that the energy that goes into planning should be added to the energy available to make a building collapse.

Originally posted by -PLB-
The part where you claim that the towers were in a state of unstable equilibrium even before the planes crashed into them. Thats the part where you completely go wrong.

I really don't have anything to add, just that is very amusing. Thanks for the laugh.

Akareyon 1 PLB 0