Some Calculations requested regarding why the towers upper portion did not slide off

[Furcifer]

No, I'm saying that the top sections of the towers had nowhere to go but down when the collapse started.

What? And totally rule out UP!

Don't laugh but I've got this debate going on over a ColbertNation with a guy who says the explosions sucked the building down at twice the speed they "should have" fallen (based on some paper a nutter over at scholars for truth has posted the collapse should have taken 25 seconds)

Nevermind, it's hysterical, go ahead and laugh.

 

[WildCat]

Imagine a beam of steel and apply a moment at each end. Imagine then that each end fails catostropically such that the stored elastic energy of the bent beam is suddenly released. The beam will displace in a horizontal direction.

This is basic engineering concerning buckling and collapse. You can simulate this by taking something with a moderate elastic modulus and bending it between your thumb and forefinger and allowing it to slide off the fingers. Note how the sample flies outwards. Kids learn this trick at an early age. Why didn't you?

Lurker

I've used the example before of hitting a nail slightly off center so that instead driving it into the wood it flys off in some direction. I think just about everyone has experienced this themselves, and that the same effect would be seen on a much larger scale from a ginormous (yes it's officially a word now!) building collapsing. But troofers don't seem to be able to grasp such a simple concept.

 

[William Rea]

Imagine a beam of steel and apply a moment at each end. Imagine then that each end fails catostropically such that the stored elastic energy of the bent beam is suddenly released. The beam will displace in a horizontal direction.

This is basic engineering concerning buckling and collapse. You can simulate this by taking something with a moderate elastic modulus and bending it between your thumb and forefinger and allowing it to slide off the fingers. Note how the sample flies outwards. Kids learn this trick at an early age. Why didn't you?

Lurker

It's probably not that people aren't aware of the phenomenon, it's just that the mechanism you describe appears irrelevant.

I'd like to see your data on how all this internal elastic strain energy is being transmitted and how it is being released.

 

[Furcifer]

I'd like to see your data on how all this internal elastic strain energy is being transmitted and how it is being released.

F= Fxsin(theta) + Fycos(theta)

 

[TruthSeeker1234]

No, I'm saying that the top sections of the towers had nowhere to go but down when the collapse started.

So tell me where the hat trusses and the the broadcast tower ended up.

And if it was a collapse, tell me why the top sections become half their height before the bottom sections move at all.

 

[BillyRayValentine]

And if it was a collapse, tell me why the top sections become half their height before the bottom sections move at all.

What is it that motivates a person to make claims that are blatantly contradicted by a mountain of evidence, including crystal clear videos? I really am baffled.

Whatever the source of your fearlessness, it seems to have affected your sense of shame as well.

 

[CHF]

So tell me where the hat trusses and the the broadcast tower ended up.

And if it was a collapse, tell me why the top sections become half their height before the bottom sections move at all.

I told you already: Judy Wood's laser beam dustified it.

 

[fitzgibbon]

What is it that motivates a person to make claims that are blatantly contradicted by a mountain of evidence, including crystal clear videos? I really am baffled.

Whatever the source of your fearlessness, it seems to have affected your sense of shame as well.

Big Lie© thinking, BRV. If typed (even by himself), it can be referenced back to as supporting 'evidence' even if proven wrong. As for shame, there's no sense; it's a learned behaviour which I have to presume TS1234 hasn't.

 

[Alt+F4]

I told you already: Judy Wood's laser beam dustified it.

Too bad Dr. Judy can't:
1. describe the weapon.
2. explain how it works.
3. understand how a kitchen microwave oven works.

But hey, who needs science when you have a cool word like dustification...

 

[HeyLeroy]

What? And totally rule out UP!
(snip)

C'mon, you know that in Michigan they call it "The Yoop".

So tell me where the hat trusses and the the broadcast tower ended up.

And if it was a collapse, tell me why the top sections become half their height before the bottom sections move at all.

Was Steven Jones lying?

 

[Newtons Bit]

So tell me where the hat trusses and the the broadcast tower ended up.

And if it was a collapse, tell me why the top sections become half their height before the bottom sections move at all.

That's actually fairly simple to understand. With the first impact of the upper block, the floors and trusses all expierenced a sudden impulse deacceleration. With f=ma, this force easily overcomes the connections of the floors to the columns. An equal and opposite force is applied to the lower block, however the energy required to detach the floors is much much less than the energy required to buckle columns. The floors detach and "free-fall". Each one hitting the floor below until there is sufficient mass and dynamic loading to cause the first columns in the upper block to fail. From there it's more of a standard pancake collapse.

 

[Corsair 115]

Too bad Dr. Judy can't:
1. describe the weapon.
2. explain how it works.
3. understand how a kitchen microwave oven works.

I'd suggest a fourth question: 4) Explain when this weapon was put into orbit. I'd imagine such a weapon with such power would have to be considerably large device, and there aren't many launch vehicles in the U.S. inventory that can put large payloads into oribt.

I'm assuming of course that she says this weapon is in low Earth orbit. This raises its own problems since in LEO an object will not be spending very long over the same part of the Earth's surface.

 

[pomeroo]

That's actually fairly simple to understand.

If it has anything to do with real science, it isn't simple for Ace to understand.

]

With the first impact of the upper block, the floors and trusses all expierenced a sudden impulse deacceleration. With f=ma, this force easily overcomes the connections of the floors to the columns. An equal and opposite force is applied to the lower block, however the energy required to detach the floors is much much less than the energy required to buckle columns. The floors detach and "free-fall". Each one hitting the floor below until there is sufficient mass and dynamic loading to cause the first columns in the upper block to fail. From there it's more of a standard pancake collapse.

Nope. It's turtles all the way down.

 

[pomeroo]

I'd suggest a fourth question: 4) Explain when this weapon was put into orbit. I'd imagine such a weapon with such power would have to be considerably large device, and there aren't many launch vehicles in the U.S. inventory that can put large payloads into oribt.

I'm assuming of course that she says this weapon is in low Earth orbit. This raises its own problems since in LEO an object will not be spending very long over the same part of the Earth's surface.

The fifth question is the one Ace really dislikes:

Why are these super-weapons, which will not be available on Earth for decades, at the disposal of the Bush/Cheney crime family, WHILE THE MILITARY HAS NO ACCESS TO THEM? Where do they show up in the budget? Why don't any Democrats complain?

Ace's first and only hapless attempt to justify Judy's fairy tale was to pretend that Fetzer's imaginary 2.3 TRILLION dollars covered the costs of R & D.

Everyone laughed at him, just as they laugh at Fetzer.

 

[lozenge124]

That's actually fairly simple to understand. With the first impact of the upper block, the floors and trusses all expierenced a sudden impulse deacceleration. With f=ma, this force easily overcomes the connections of the floors to the columns. An equal and opposite force is applied to the lower block, however the energy required to detach the floors is much much less than the energy required to buckle columns. The floors detach and "free-fall". Each one hitting the floor below until there is sufficient mass and dynamic loading to cause the first columns in the upper block to fail. From there it's more of a standard pancake collapse.

Except that neither NIST nor the latest Bazant/Greening paper endorses the pancake collapse:

NIST’s findings do not support the “pancake theory” of collapse, which is premised on a progressive failure of the floor systems in the WTC towers (the composite floor system—that connected the core columns and the perimeter columns—consisted of a grid of steel “trusses” integrated with a concrete slab; see diagram below). Instead, the NIST investigation showed conclusively that the failure of the inwardly bowed perimeter columns initiated collapse and that the occurrence of this inward bowing required the sagging floors to remain connected to the columns and pull the columns inwards. Thus, the floors did not fail progressively to cause a pancaking phenomenon.

http://wtc.nist.gov/pubs/factsheets/faqs_8_2006.htm

In the structural engineering community, one early speculation was that, because of a supposedly insufficient strength of the connections between the floor trusses and the columns, the floors ‘pancaked’ first, leaving an empty framed tube, which later lost stability. This hypothesis, however, was invalidated at NIST by careful examination of the photographic record, which shows some perimeter columns to be deflected by about 1 m inward. NIST explains this deflection by a horizontal pull from catenary action of floor trusses as they sag due to differential thermal expansion as well as creep. Such action would have been impossible if the floor trusses disconnected from the perimeter columns.

http://www.civil.northwestern.edu/p...se - What Did & Did Not Cause It - 5-2007.pdf

 

[William Rea]

That's actually fairly simple to understand. With the first impact of the upper block, the floors and trusses all expierenced a sudden impulse deacceleration. With f=ma, this force easily overcomes the connections of the floors to the columns. An equal and opposite force is applied to the lower block, however the energy required to detach the floors is much much less than the energy required to buckle columns. The floors detach and "free-fall". Each one hitting the floor below until there is sufficient mass and dynamic loading to cause the first columns in the upper block to fail. From there it's more of a standard pancake collapse.

Hold on, hold on. From what I have read this needs some work. Where is the data regarding the impulse force required to detach the undamaged floors in the upper block?

This impulse deceleration you talk about implies that the steel superstructure of the upper block does not "crumple" into that of the lower block (like the front end of a car in a crash). What you seem to be saying is that the steel superstructure comes to a sudden halt and the inertia of the floors means they detach and fall into the lower block (like the passengers getting thrown through the windscreen). If this is so then wouldn't we expect to see major evidence of destruction associated with relatively minor vertical movement of the outer steel superstructure. Is this the case?

 

[Revolutionary91]

Hold on, hold on. From what I have read this needs some work. Where is the data regarding the impulse force required to detach the undamaged floors in the upper block?

This impulse deceleration you talk about implies that the steel superstructure of the upper block does not "crumple" into that of the lower block (like the front end of a car in a crash). What you seem to be saying is that the steel superstructure comes to a sudden halt and the inertia of the floors means they detach and fall into the lower block (like the passengers getting thrown through the windscreen). If this is so then wouldn't we expect to see major evidence of destruction associated with relatively minor vertical movement of the outer steel superstructure. Is this the case?

I'm still waiting for a JREFer to explain this footage:

Dr. Bazant's theory tells us that the energy would concentrate in and crush the volume below the aircraft impact level.

These photographs clearly show that the first volume to be crushed was a volume of the upper section. Dr. Bazant has supplied us with a physical measure of the movement of the roof of the tower. He has asked us to believe that this acceleration of the roof line was the same as the lower end of the upper section, because the upper section remained whole and rigid. This is easily revealed to not be the case. Far from being a measure of the progress of the collapse front down the tower, it is actually a measure of the progress of the destruction of the upper section. The foundation of the entire argument can be undermined simply by showing one undeniable sequence of events.

http://www.911blogger.com/node/9154

 

[TruthSeeker1234]

Yes, I posted a similar graphic months and months ago, with no answer.

It was in my thread about "Dr. Greening Refuted Easily". Eventually in an email to me, Greening said that the walls in the upper block slipped inside of the walls of the lower block. LOL, that's what he said. I'm not sure if he still says that or not.

Greening also never answered me on why the smoke from the fires would go from dark black to white as soon as the towers "collapsed". I would think the fuel would be the same stuff, with less oxygen if anything.

 

[Furcifer]

I'm not sure about he rest of the "JREF'ers", but I agree with the notion that a volume of the upper section underwent progressive collapse as the lower section underwent progressive collapse. "Crushed together" for the first few seconds of collapse. I'm not sure what you hope to prove with this? At some point the upper section did get crushed, to treat it before , after or during the colpase of the lower does little to change the validity of the math involved. It just changes the density of the crushing front. I believe Bazant admits this in the BandV paper if I remember correctly.
What do you think it means Rev91?

 

[William Rea]

Yes, I posted a similar graphic months and months ago, with no answer.

It was in my thread about "Dr. Greening Refuted Easily". Eventually in an email to me, Greening said that the walls in the upper block slipped inside of the walls of the lower block. LOL, that's what he said. I'm not sure if he still says that or not.

Greening also never answered me on why the smoke from the fires would go from dark black to white as soon as the towers "collapsed". I would think the fuel would be the same stuff, with less oxygen if anything.

The walls were bowing inwards according to eye witness testimony so how did they slide inside?