Has Anyone Seen A Realistice Explanation For Free Fall Of The Towers?

[einsteen]

Ok, I don't care, what I'm interested in is, how could the block reach a speed of sqrt(2gh) to collapse on the next floor ?

Physical processes are continue processes, why at t=0 does the block completely fall in vacuum ? at t=0 in fact an area is assumed with all mass concentrated. This is not possible if you assume steal weakens, I would expect in a continue process that the block just caves in one floor continuously. Why is it there for an hour and then after one hour it is completely free and is able to move 3.7 meters in the whole area.

But of course NIST has the answer, please could you give the the link of the report that explains this, I couldn't find it.

 

[bob_kark]

You didn't explain what this is if it is not the concrete core you are not being reasonable and you are wasting our time.

What is unreasonable about asking you to stand behind the evidence you provide? Simply demonstrate how it is possible to determine the identity of the materials from the pictures you are showing. Why do you not consider this a reasonable request?

 

[uruk]

Just wanted to remind Christophera that thermite does not explode.

http://www.youtube.com/watch?v=ld1rlBAfK_I
http://video.google.com/videoplay?docid=2289367460324643450&q=grenade

 

[chipmunk stew]

What is unreasonable about asking you to stand behind the evidence you provide? Simply demonstrate how it is possible to determine the identity of the materials from the pictures you are showing. Why do you not consider this a reasonable request?

Because he is not a reasonable person. If history is any guide, he will be hammering away at the same points with the same tenacity in the same language on some forum five years from now. It's not stubbornness--it's illness. He actually, literally sees what he says he sees. Nothing you say can convince him otherwise.

To those of you who may be relatively new to christophera, he really is seriously mentally ill. You can find links to his various sites that prove this unconditionally in this very thread (search the time frame around 2-3 weeks ago in this thread and you'll find everything you need to know about him).

But in light of that reality, it is probably best not to engage with him over the same two posts and the same two photos that he's been spouting here for the past few months and that he's been spouting for the past few years on various forums. Just read the links and you will understand. Personally, I'd prefer that when his ultimate meltdown occurs, it is on a forum other than JREF.

As annoying as he is, as obvious as it is that his theories are indefensible and nonsensical, as apparent as it is that he's the only person on the face of the earth who believes that the twin towers had concrete cores, he really is seriously mentally ill. No joke. So, please, take the high road and let this thread die despite the temptation to respond to his nonsensical posts.

 

[chipmunk stew]

-the situation is extremely nonlineair and onze the 'block' falls it becomes chaotic, there is enough time for the assumed block to find a path of less resistance

- the speed after one floor is assumed to give the block enough energy to break everything between the block, an initial speed of sqrt(2gh_floor) is assumed. Well assuming that the last thing that is able to keep the block that high (for an hour) breaks, what would be what breaks, in fact they mean at t=0 the block can freely move a distance of 3.7meter to get its initial speed, why would this complete block getting that initial speed.
That is not realistic. First of all 3.7 meter is between the center of masses of the floors, but the floors have a width and what about the plane that is still there and all other stuff, that doesn't give the free 3.7 meter to travel. I would expect that only one part of the block gets a space to travel 1 meter and then, the rest breaks with this, but then the velocity that it reaches when it is at the next floor will be much lower. Kinetic energy goes with v^2 which means that the energy will be much lower in general, much lower. There is so much more that is not taken into account, mass scattering away, the block that will destroy also etc.

Remember, it's not really a "block", it's a wad of debris that happens to be arranged in a stable configuration.

Remember, too, how massive this "wad" is--millions of pounds. The initial failure causing PE to convert to KE would be localized, but for every failed structural member, the stress and strain on the remaining members would increase, causing a rapidly accelerating chain reaction of failures. Given the enormity of the wad's mass, it's reasonable to expect that this chain reaction would have been nearly instantaneous. Also given the wad's enormity, I wouldn't expect any plane or other debris to slow the initial drop significantly. The velocity at the initial impact leading to global collapse would be very near the velocity it would be at freefall.

 

[einsteen]

I more mean, take a book, place 4 blocks of ice in the corners and place another book on it, take the heaviest book you can find and the smallest iceblocks, but strong enough to carry the book. Maybe ice is no good example, let's take some plastic or metal whatever you want, the weakest material that you can think of with the properties its strength is heat-dependent. Do an experiment in which you heat the metal.

Why would the book not go down slowly ? Why is it assumed to have it's height of 3.7 cm and at t=0 it's in vacuum. melting/weakening etc is a continuous process, like all things in physics. We have no sawtooth functions working somewhere, especially not after an hour, a lot of functions go with exp(-k1*t/k2). What happened here ? I don't know.

of course it is no 'block', mass is mass ok but debris even makes it more difficult, then a small part will drop, another small part will drop etc.

I think you can earn a lot of money if you can proof it, wouldn't that be nice, you ◊◊◊◊ the CT'ers and get money also, what more do you want ?

 

[MortFurd]

I more mean, take a book, place 4 blocks of ice in the corners and place another book on it, take the heaviest book you can find and the smallest iceblocks, but strong enough to carry the book. Maybe ice is no good example, let's take some plastic or metal whatever you want, the weakest material that you can think of with the properties its strength is heat-dependent. Do an experiment in which you heat the metal.

Why would the book not go down slowly ? Why is it assumed to have it's height of 3.7 cm and at t=0 it's in vacuum. melting/weakening etc is a continuous process, like all things in physics. We have no sawtooth functions working somewhere, especially not after an hour, a lot of functions go with exp(-k1*t/k2). What happened here ? I don't know.

of course it is no 'block', mass is mass ok but debris even makes it more difficult, then a small part will drop, another small part will drop etc.

I think you can earn a lot of money if you can proof it, wouldn't that be nice, you ◊◊◊◊ the CT'ers and get money also, what more do you want ?

First off, no one here says it was in vacuum.

About the closest working model I can think of that you might build at home would be to use the sheet metal channels that are sometime used in building partition walls in houses. These are about the dimensions of a 2x4, but are made of sheet metal. They frame the wall and hang sheet rock on the stuff.

If you built a model of a section of the WTC (ten floors or so) about the area of large living room, you might be able to learn something. That's about the closest I can WAG the dimensions. Someone here with real engineering experience could probably come up with a more accurate scaling, but they'd also say that the attempt will be inherently inaccurate and not neccessarily representative of the WTC situation - which is all true.

The point I'm trying to make is that material strength and mass do not scale linearly with size changes. If you make a structure like the WTC at a smaller scale, at will be stronger by far than ther real WTC was. If you want to simulate the WTC, you have to go with software (which has its own inaccuracies) or with a structure whose materials and dimensions have been scaled to match mass to size and strength strength to size ratios. To be really accurate, you'd have to build a full size structure (or at least a section of it.)

Your books will act like rigid blocks. The WTC buildings were flexible steel structures. Big difference in response right there.

The collapsing section (where the plane hit) did not melt like an ice cube. The steel columns continued to stand until some over stressed (too hot, and trying to carry too much load from missing neighbors) column buckled. That one then left its neighbors to carry more load until one of them collpased, and so on. In just a few seconds that process could expand until even undamaged columns can no longer carry the load on them. Once you've got columns (and beams) collapsing, there's no reason for them to stop. The structure still has a load to carry, and less and less memebers to carry it.

Your mistake is still in assuming that the collapsing section will respond like a block. It will not.

 

[einsteen]

Yeah, a scale model will not really work of course. My knowledge is a little bit based on the Greening pre-print because it's an excellent paper that exactly calculates the collapse time under the assumptions that are assumed (if that is proper English?). One of the assumptions is that the energy of the initial falling block is enough to cause pancaking, only if a small precentage of the energy is enough to break the floors and all other stuff, in fact that means that the energy should be enough to compress all the mass within or press it out in all directions. In fact it is assumed for the initial 'block' that it travels a distance about 410/110 meter, it needs that distance to get suff. speed. IMO the paper disproves what it wants to prove.

 

[rwguinn]

Yeah, a scale model will not really work of course. My knowledge is a little bit based on the Greening pre-print because it's an excellent paper that exactly calculates the collapse time under the assumptions that are assumed (if that is proper English?). One of the assumptions is that the energy of the initial falling block is enough to cause pancaking, only if a small precentage of the energy is enough to break the floors and all other stuff, in fact that means that the energy should be enough to compress all the mass within or press it out in all directions. In fact it is assumed for the initial 'block' that it travels a distance about 410/110 meter, it needs that distance to get suff. speed. IMO the paper disproves what it wants to prove.

The buildings stood for a very long time with significant numbers of supports missing. These were pretty much all on one side.
The fire weakened sufficient numbers of the remaining members to the point where one or more could no longer react the bending moment imposed by the failure on one side of the building, and it/they failed, and what was left were then doomed to fail.
Such failure is not plastic. It was catastrophic. When you yield steel, you are putting energy in. That energy reduces to its lowest form, heat, which further weakens the steel, which cannot dissipate it very quickly--and rubture is abrupt and catastrophic.
With no support, the upper "block" falls free and impacts the next level, which fails catastrophically, ad infinitum.

 

[Christophera]

Oh, you mean this:

So, you think you can just blow up the outside of the building, then wait, and then detonate the core, which is still standing on its own ?

Good thing you don't build houses.

Apparently you have your terms confused. There is something suspiciously naive or phoney about this comment. Building houses is one thing, demoliton another. I've scratched the surface of both over years, on occasion.

There were 2 distinct systems one that demolished the core and another for floors.

After your ridiculous mixing of terms, I know you will not or cannot reason, so this isn't for you.

Consider:
If you are going to design an exploding building and build it safely you build it so that it is segmented and one segment does not detonate an adjoining segement. If one goes off, it stops there. You have to make each segment have separate detonators.

The different systems were; Reinforced concrete core had RDX coated rebar, floors had it in the corrugations and there was a special dual plate system that was built into the floors to cut columns, ( EXPLO. shear & torch Cut on columns left shear, right torch.).

The documentary had a bit about plates with ridiculous tolerences surrounding each interior box columns. Justifying the high cost of the towers was actually a part of the grant the videographers so the tracked down an engineering company of a list given to them by the PA and received all the old drawings produced by the company and found tempered steel plates specified to very tight tolerences for the type component. When they went to the PA the PA was upset that the engineering company had released the old drawings, and data. They had considered them classified at the time. It was near the end of the ducumentary.

The below diagram describes the concept accomodated by the tolerences and position of the plates. They filled the truncated corners of the trussed floor panels where they connected to the interior box column. There is something fully feasible and logical about using one system of super high pressures gasses to cut steel strcuture then using an interior concrete strcuture that throws the steel materials outward with a controlled heave.

http://www.internationalskeptics.com/forums/attachment.php?attachmentid=3271&stc=1&d=1159228581

 

[Christophera]

What is unreasonable about asking you to stand behind the evidence you provide? Simply demonstrate how it is possible to determine the identity of the materials from the pictures you are showing. Why do you not consider this a reasonable request?

My reasoning is not evidence. Y

Demonstratons of logic showing the shape of the WTC 2 core can only be concrete will require you brain to ba active and your heart large enough to care about Amrica enough to use logic.

Common snes with logic say it must be concrete because there is no steel seen. It does no look like steel and other images show what mut be concrete and not steel. Redundancy consistent with common logic. Done deal.

FEMA lied.

 

[LashL]

My reasoning is not evidence. Y [sic]

Demonstratons [sic] of logic showing the shape of the WTC 2 core can only be concrete [???] will require you [sic] brain to ba [sic] active and your heart large enough to care about Amrica [sic] enough to use logic.

Common snes [sic] with logic say [sic] it must be concrete because there is no steel seen [sic]. It does no [sic] look like steel and other images show what mut [sic] be concrete and not steel. Redundancy consistent with common logic [???]. Done deal.

FEMA lied.

Chris,

Please get help. Nobody here wishes to watch you implode, by controlled demolition or otherwise, but it does appear that you are getting worse when your language, spelling, and grammar become so horrible, and when your posts do not even make any sense.

Please, take a break from the internet and seek the help you need.

 

[Skylark]

Enough with the concrete core BS already...

Read this and get some help.

 

[bob_kark]

My reasoning is not evidence. Y

Demonstratons of logic showing the shape of the WTC 2 core can only be concrete will require you brain to ba active and your heart large enough to care about Amrica enough to use logic.

Common snes with logic say it must be concrete because there is no steel seen. It does no look like steel and other images show what mut be concrete and not steel. Redundancy consistent with common logic. Done deal.

FEMA lied.

I will only say this once. Please, never insinuate that I do not care about my country. That's a very low blow and is completely uncalled for. Let's stick to the subject at hand.

You're claiming that the structure in the picture does not look like steel, therefore it must be concrete. How can you tell? The picture is taken from such a great distance that you can not judge texture, much less color.

However, you bring up an interesting point, common sense. Let me ask you this, would a structure that was built to be able to withstand high wind loads be built with a concrete core or a steel beam core? Which one seems more likely to bend and absorb the energy from high winds? In addition, which material would you say would be more suited for large open spaces such as in the WTC? Also, the WTC would have been nearly double the tallest concrete building in the world at the time, One Shell Plaza. So from a building stand point, wouldn't you believe steel would make far more sense than concrete ever would for the WTC? What benefit would concrete provide?

But let's get back to your claim. You state that you have other images that show concrete. Could you provide them?

 

[Christophera]

I consider your rebuke to my questioning you loyalty to the principles of our nation to be sincere. Meaning truth and justice are also valued, meaning you might be up the challenge of doing something important to save it.

You're claiming that the structure in the picture does not look like steel, therefore it must be concrete. How can you tell? The picture is taken from such a great distance that you can not judge texture, much less color.

You've got it, then you twist away from it.

Structural steel during failure is very distinct. When we see it at the WTC, we can see what it is if one knows what its distinct characteristces are. In the absense of those characteristics we must look to what characteristics other matreials have that could survive the tousands of tons of steel crashing over it have. Seek to identify those in the decomposing structure in order to discern the material.

Now we must conside the possibilities. Lets trya few things other than concrete to see how they fits.

Wood: Check the history of wooden towers.
Stone: Definately masonry and it is stated the towers had none. cast concrete is not often called masonry in engineering and archcitecture. Check the history of stone towers.

Aluminum: Check the history of aluminum towers.
Fibeglass: Check the history of fiberglass towers.

We all have common knowledge to know that those materials just arn't used for towers.

CONCRETE: Square cast concrete corners will develop larger radius gently rounded corners with erosive forces.

 

[Skylark]

So you're saying that a concrete core would have withstood not only the "blasts" (since you say it was CD) above it, but the floors collapsing around it, where steel wouldn't have? That is your only proof that it had a concrete core?

...

BAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA no.

 

[Mancman]

-the situation is extremely nonlineair and onze the 'block' falls it becomes chaotic, there is enough time for the assumed block to find a path of less resistance

- the speed after one floor is assumed to give the block enough energy to break everything between the block, an initial speed of sqrt(2gh_floor) is assumed. Well assuming that the last thing that is able to keep the block that high (for an hour) breaks, what would be what breaks, in fact they mean at t=0 the block can freely move a distance of 3.7meter to get its initial speed, why would this complete block getting that initial speed.
That is not realistic. First of all 3.7 meter is between the center of masses of the floors, but the floors have a width and what about the plane that is still there and all other stuff, that doesn't give the free 3.7 meter to travel. I would expect that only one part of the block gets a space to travel 1 meter and then, the rest breaks with this, but then the velocity that it reaches when it is at the next floor will be much lower. Kinetic energy goes with v^2 which means that the energy will be much lower in general, much lower. There is so much more that is not taken into account, mass scattering away, the block that will destroy also etc.

What resistance is there going to be between one floorslab and another? Some burnt desks, chairs, partition walls, and shreds of plane? These are going to absorb all the energy and slow down a 1000 ton floorslab? Wow.

 

[Belz...]

After your ridiculous mixing of terms, I know you will not or cannot reason, so this isn't for you.

I'm not mixing terms, I'm trying to make heads and tails out of your ridiculous theory.

If you are going to design an exploding building and build it safely you build it so that it is segmented and one segment does not detonate an adjoining segement. If one goes off, it stops there. You have to make each segment have separate detonators.

Why not just ram big planes into the buildings and let the fire do the rest of the work ?

 

[Belz...]

My reasoning is not evidence.

Damn straight.

Demonstratons of logic showing the shape of the WTC 2 core can only be concrete will require you brain to ba active and your heart large enough to care about Amrica enough to use logic.

Nonsensical assertion of the day.

Common snes with logic

Leave Nintendo out of this.

say it must be concrete because there is no steel seen.

False dichotomy.

It does no look like steel and other images show what mut be concrete and not steel. Redundancy consistent with common logic. Done deal.

"I'm right, therefore I am correct. Ergo, I win."

 

[Belz...]

Oh, please, chris, answer Bob's question:

However, you bring up an interesting point, common sense. Let me ask you this, would a structure that was built to be able to withstand high wind loads be built with a concrete core or a steel beam core? Which one seems more likely to bend and absorb the energy from high winds? In addition, which material would you say would be more suited for large open spaces such as in the WTC? Also, the WTC would have been nearly double the tallest concrete building in the world at the time, One Shell Plaza. So from a building stand point, wouldn't you believe steel would make far more sense than concrete ever would for the WTC? What benefit would concrete provide?