QUOTE (FactCheck+Jun 23 2007, 08:19 PM)
I believe this is a very important part of the collapse and I'm waiting for one of physorgs greats like NEU-FONZE and DBB to depict this in a paper.
There must be a way to design tall buildings which fall apart and straight down instead of opening like a flower.
Thank you, but I don't think it important whether the zone B crushed mass is considered to be solid or more like a fluid. Either way it is just mass and protects the zone A top block from (much) further damage.
Yes, structural engineers are interested in finding ways to make just that happen. The issue is in the infrequent great (magnitude at least 8.0) and stupendous (magnitude at least 9.0) earthquakes. While it may be possible to design buildings which do not collapse in great earthquakes, it may not be for the stupendous ones. Some small risk must be taken.
To show how small this risk is, there have only been three stupendous earthquakes in the last one hundred years, one in Alaska, one in Chile and one in the Indian Ocean. These three account for about sixty percent of all the seismic energy released in that time.
There must be a way to design tall buildings which fall apart and straight down instead of opening like a flower.
Thank you, but I don't think it important whether the zone B crushed mass is considered to be solid or more like a fluid. Either way it is just mass and protects the zone A top block from (much) further damage.
Yes, structural engineers are interested in finding ways to make just that happen. The issue is in the infrequent great (magnitude at least 8.0) and stupendous (magnitude at least 9.0) earthquakes. While it may be possible to design buildings which do not collapse in great earthquakes, it may not be for the stupendous ones. Some small risk must be taken.
To show how small this risk is, there have only been three stupendous earthquakes in the last one hundred years, one in Alaska, one in Chile and one in the Indian Ocean. These three account for about sixty percent of all the seismic energy released in that time.
QUOTE (David B. Benson+Jun 23 2007, 09:40 PM)
Well, try the rail car setup. The rail car on the left is attached via a line over a pulley at the right to a pan with weights. Somewhat to its right is another rail car to which it will couple. Repeat with as many rail cars as will appropriately fit of the rail. Let go of the line and observe.
So you believe the rail cars on the right will disintegrate one at a time as the left car (pulled by the falling pan weights) barrels through them?
When the first collision takes place, the impact force is transferred through the rail car buffers, the rail cars act together as one system. This, to me at least, is a clear example where the hypothesis "Energy is dissipated only at the crushing front" would appear to be invalid.
But if you can get some kind of progressive scenario analogous to the WTC "crush down" to happen in your lab with this setup, then yes I would like to see it. Please post images or video. Or describe what you think happens, I'd certainly be interested to know!
So you believe the rail cars on the right will disintegrate one at a time as the left car (pulled by the falling pan weights) barrels through them?
When the first collision takes place, the impact force is transferred through the rail car buffers, the rail cars act together as one system. This, to me at least, is a clear example where the hypothesis "Energy is dissipated only at the crushing front" would appear to be invalid.
But if you can get some kind of progressive scenario analogous to the WTC "crush down" to happen in your lab with this setup, then yes I would like to see it. Please post images or video. Or describe what you think happens, I'd certainly be interested to know!
A paper on the web by Daniel A. Vellone & Charles Merguerian seems to indicate the UCS (unconfined compressive strength) of the underlying Manhattan schist bedrock was 70--90 MPa. (Maybe they meant GPa?) Thus the necessity of spreading the core column load over a wider footing, I think.
However, the paper by Song/Suh/Woo/Hao in Engineering Geology 72:3--4, April 2004, 293--308, indicates that the elasticity, under confinement, increases with the confining pressure, but anyway, seems to be about 80 GPa.
From Wikipedia, high-strength concrete has a Young's modulus of about 30 GPa, while for steel it is about 200 Gpa.
I'll say there is a serious impedance mismatch.
However, the paper by Song/Suh/Woo/Hao in Engineering Geology 72:3--4, April 2004, 293--308, indicates that the elasticity, under confinement, increases with the confining pressure, but anyway, seems to be about 80 GPa.
From Wikipedia, high-strength concrete has a Young's modulus of about 30 GPa, while for steel it is about 200 Gpa.
I'll say there is a serious impedance mismatch.
QUOTE (lozenge124+Jun 23 2007, 11:26 PM)
So you believe the rail cars on the right will disintegrate one at a time as the left car (pulled by the falling pan weights) barrels through them?
When the first collision takes place, the impact force is transferred through the rail car buffers, the rail cars act together as one system. This, to me at least, is a clear example where the hypothesis "Energy is dissipated only at the crushing front" would appear to be invalid.
But if you can get some kind of progressive scenario analogous to the WTC "crush down" to happen in your lab with this setup, then yes I would like to see it. Please post images or video. Or describe what you think happens, I'd certainly be interested to know!
(1) No, of course not.
(2) But the coupler action consumes energy. This is a bit easier to see and understand using the physics lab rail cars. These come with Velcro bands which can be snapped on. When the cars collide, energy is consumed in the inelastic behavior of the Velcro.
(3) I'm not going to do the lab work. (I did a somewhat similar, but vertical, setup to determine the small pendulum law's dependence on the force of gravity in 1959. It took all quarter to get the experiment to work, but the two of us obtained results with about 6%! I know how much time, thought and effort good lab work requires.) I already know the outcome. It will be quite nicely described via Greening's floor-by-floor crush-down methods. But if you doubt this, please give it a try! I'd like to know the outcomes as well. Furthermore, I am sure that The Physics Teacher, or a similar publication, will be happy to publish it. They are always looking for lab experiments which will interest students.
Edited to add: Adding some origami-style paper accordions which have to be folded up before the rail cars couple would increase the energy consumed.
When the first collision takes place, the impact force is transferred through the rail car buffers, the rail cars act together as one system. This, to me at least, is a clear example where the hypothesis "Energy is dissipated only at the crushing front" would appear to be invalid.
But if you can get some kind of progressive scenario analogous to the WTC "crush down" to happen in your lab with this setup, then yes I would like to see it. Please post images or video. Or describe what you think happens, I'd certainly be interested to know!
(1) No, of course not.
(2) But the coupler action consumes energy. This is a bit easier to see and understand using the physics lab rail cars. These come with Velcro bands which can be snapped on. When the cars collide, energy is consumed in the inelastic behavior of the Velcro.
(3) I'm not going to do the lab work. (I did a somewhat similar, but vertical, setup to determine the small pendulum law's dependence on the force of gravity in 1959. It took all quarter to get the experiment to work, but the two of us obtained results with about 6%! I know how much time, thought and effort good lab work requires.) I already know the outcome. It will be quite nicely described via Greening's floor-by-floor crush-down methods. But if you doubt this, please give it a try! I'd like to know the outcomes as well. Furthermore, I am sure that The Physics Teacher, or a similar publication, will be happy to publish it. They are always looking for lab experiments which will interest students.
Edited to add: Adding some origami-style paper accordions which have to be folded up before the rail cars couple would increase the energy consumed.
QUOTE (David B. Benson+Jun 23 2007, 09:51 PM)
Thank you, but I don't think it important whether the zone B crushed mass is considered to be solid or more like a fluid. Either way it is just mass and protects the zone A top block from (much) further damage.
Yes, structural engineers are interested in finding ways to make just that happen. The issue is in the infrequent great (magnitude at least 8.0) and stupendous (magnitude at least 9.0) earthquakes. While it may be possible to design buildings which do not collapse in great earthquakes, it may not be for the stupendous ones. Some small risk must be taken.
To show how small this risk is, there have only been three stupendous earthquakes in the last one hundred years, one in Alaska, one in Chile and one in the Indian Ocean. These three account for about sixty percent of all the seismic energy released in that time.
I don't worry about earthquakes. I worry about these new computerized designs which seem to rely on fireproofing more than redundancy. That's the lesson I learned from the WTC. It was a new kind of design which is being used more and more in tall buildings to save money. If a fire was to break out in these buildings and was unfought for one reason or another I fear another global collapse could result. Though it would take hours longer with spray on fireproofing installed. A matter of time in my limited view.
It was nice to see the NIST recommending a concrete core for future high rise buildings but I understand it was a recommendation and not a federal code.
Yes, structural engineers are interested in finding ways to make just that happen. The issue is in the infrequent great (magnitude at least 8.0) and stupendous (magnitude at least 9.0) earthquakes. While it may be possible to design buildings which do not collapse in great earthquakes, it may not be for the stupendous ones. Some small risk must be taken.
To show how small this risk is, there have only been three stupendous earthquakes in the last one hundred years, one in Alaska, one in Chile and one in the Indian Ocean. These three account for about sixty percent of all the seismic energy released in that time.
I don't worry about earthquakes. I worry about these new computerized designs which seem to rely on fireproofing more than redundancy. That's the lesson I learned from the WTC. It was a new kind of design which is being used more and more in tall buildings to save money. If a fire was to break out in these buildings and was unfought for one reason or another I fear another global collapse could result. Though it would take hours longer with spray on fireproofing installed. A matter of time in my limited view.
It was nice to see the NIST recommending a concrete core for future high rise buildings but I understand it was a recommendation and not a federal code.
QUOTE (FactCheck+Jun 24 2007, 12:28 AM)
It was nice to see the NIST recommending a concrete core for future high rise buildings but I understand it was a recommendation and not a federal code.
There is no federal code. There is an international code, which is essentially adopted in its entirety in the European Union. In the USA, the building codes are state-by-state and even county-by-county and city-by-city. However, there is a growing tendency for each entity to adopt (most of) the international code plus some more local features depending upon earthquake, hurricane, etc., likelihoods...
Edited to add: I don't understand FEMA's role in all this, but it seems to have some.
There is no federal code. There is an international code, which is essentially adopted in its entirety in the European Union. In the USA, the building codes are state-by-state and even county-by-county and city-by-city. However, there is a growing tendency for each entity to adopt (most of) the international code plus some more local features depending upon earthquake, hurricane, etc., likelihoods...
Edited to add: I don't understand FEMA's role in all this, but it seems to have some.
QUOTE (David B. Benson+Jun 24 2007, 12:04 AM)
QUOTE
So you believe the rail cars on the right will disintegrate one at a time as the left car (pulled by the falling pan weights) barrels through them?
When the first collision takes place, the impact force is transferred through the rail car buffers, the rail cars act together as one system. This, to me at least, is a clear example where the hypothesis "Energy is dissipated only at the crushing front" would appear to be invalid.
But if you can get some kind of progressive scenario analogous to the WTC "crush down" to happen in your lab with this setup, then yes I would like to see it. Please post images or video. Or describe what you think happens, I'd certainly be interested to know!
When the first collision takes place, the impact force is transferred through the rail car buffers, the rail cars act together as one system. This, to me at least, is a clear example where the hypothesis "Energy is dissipated only at the crushing front" would appear to be invalid.
But if you can get some kind of progressive scenario analogous to the WTC "crush down" to happen in your lab with this setup, then yes I would like to see it. Please post images or video. Or describe what you think happens, I'd certainly be interested to know!
(1) No, of course not.
(2) But the coupler action consumes energy. This is a bit easier to see and understand using the physics lab rail cars. These come with Velcro bands which can be snapped on. When the cars collide, energy is consumed in the inelastic behavior of the Velcro.
(3) I'm not going to do the lab work. (I did a somewhat similar, but vertical, setup to determine the small pendulum law's dependence on the force of gravity in 1959. It took all quarter to get the experiment to work, but the two of us obtained results with about 6%! I know how much time, thought and effort good lab work requires.) I already know the outcome. It will be quite nicely described via Greening's floor-by-floor crush-down methods. But if you doubt this, please give it a try! I'd like to know the outcomes as well. Furthermore, I am sure that The Physics Teacher, or a similar publication, will be happy to publish it. They are always looking for lab experiments which will interest students.
Well that's not very convincing is it?
Why would the velcro between cars 1-2 absorb all the impact, with the velcro between cars 2-3,3-4 etc unaffected? And how does car 2 get out of the way/get destroyed so that the next collision, between cars 1&3, can take place?
In any case, I have never said that total progressive collapse is absolutely impossible. I am sure it is possible to rig some kind of device that will exhibit such behavior. But that would not prove that the WTC towers, with their vertical support structure, could collapse in such a fashion of course.
DBB you are the one with your name on a paper that assumes the hypothesis "Energy is dissipated only at the crushing front" in a gravity only WTC collapse. So the burden of proof is on you - though I don't think a hypothetical rail car experiment with velcro is quite going to cut it unfortunately!
QUOTE (lozenge124+Jun 24 2007, 12:41 AM)
Well that's not very convincing is it?
So the burden of proof is on you ...
Well, it should be. And no, you haven't thought it through. Cars 1 hits car 2. Together, cars 1&2 hit car 3, a bit further down the rail. And so on. The horizontal equivalent of the mass accumulation of the crushing front in crush-down.
In empirical science there is no proof. There is only the ability to compare hypotheses, with of course, preference given to those hypotheses which do not contradict well established principles such a Newton's laws. The crush-down equation is Newton's laws, applied in a one-dimensional fashion. The same equation will work for the rail cars, with different parameters, of course. The same equation, applied in a time-reversed sense, works for rockets, with still different parameters.
Isn't that enough evidence for you? I suppose nothing ever will be...
So the burden of proof is on you ...
Well, it should be. And no, you haven't thought it through. Cars 1 hits car 2. Together, cars 1&2 hit car 3, a bit further down the rail. And so on. The horizontal equivalent of the mass accumulation of the crushing front in crush-down.
In empirical science there is no proof. There is only the ability to compare hypotheses, with of course, preference given to those hypotheses which do not contradict well established principles such a Newton's laws. The crush-down equation is Newton's laws, applied in a one-dimensional fashion. The same equation will work for the rail cars, with different parameters, of course. The same equation, applied in a time-reversed sense, works for rockets, with still different parameters.
Isn't that enough evidence for you? I suppose nothing ever will be...
QUOTE (David B. Benson+Jun 24 2007, 12:55 AM)
Well, it should be. And no, you haven't thought it through. Cars 1 hits car 2. Together, cars 1&2 hits car 3. And so on. The horizontal equivalent of the mass accumulation of the crushing front in crush-down.
OK, I see. Yes I am very familiar with this phenomena. There is a train depot near a park where I go where you can sometimes hear this "collision front" propagate down the train cars when a train engine first couples to them and pushes them back.
I am very surprised (and a little disappointed) that you think this has any relevance to the puzzle of the progressive nature of the WTC collapse, with its perimeter columns blowing out laterally floor by floor.
No, I just say that when the floor has too much weight on it, it collapses, and when it collapses, it drops the load that made *it* collapse onto the floor below it.
By whatever mechanism/definition of "collapse" you feel reasonable, floors do *collapse*, and when they do, they drop their load to the next-lower floor.
Which itself collapses, in turn.
Maybe they're stupid, too.
You are still either ducking or missing the point. Or, perhaps, there's a language problem.
Not only don't I doubt that, if you could get floors collapsing, the collapsing would continue, I have written about this, myself, in this forum. Indeed, does not the chicken wire WTC plus aluminum foil analogy make this clear? But what about the columns? They will not collapse just because you say "boo".
I'm also well aware that floor panels helped to stabilize the columns. However, stability did not come just from the floor panels, and even if you used, say, balsa wood "floors" instead of aluminum foil "floors" in the chicken wire model, I think you know perfectly well that collapsing those "floors" in the manner we are discussing will not cause the chicken wire to collapse.
Now that you understand the point, do tell us if I am being presumptuous, and that your engineering intuition tells you that the chicken wire "columns" would collapse, also.
No, they'll collapse regardless of whatever either of us say, all on their own. They're unstable, and they can't support themselves. This is the problem with tinkertoy "models" of the WTC, they aren't to-scale.
Balsa wood floors? Is that balsa wood 600x thinner than the floor's width? If not, it's grossly overbuilt. The concrete floors were 4" thick, and 208' on each side.
The perimeter columns were heavy, but they were also relatively thin compared to their width and height. Don't take my word for it, just look at the videos, the floors fall before the walls, and the walls splay outward and break apart. Calculate the tension on the welds holding them together as they lean outward.
The force that *can* work throughout the structure, *once it gets to the structure*, does work through the structure. The other fraction of the force accelerates mass and damages frangible materials along the way.
Visualize a bank safe from the 100th floor plummeting through the floors - Some of it's kinetic energy is delivered to the floor structure (making a "BANG!" that'll be heard at ground level almost instantly due to the speed of sound in steel being 20,000 fps), some of it will just be smashing a hole in the concrete (accelerating the previously stationary concrete to the safe's current speed), and the rest of it just keeps accelerating the safe.
The force of the falling stuff doesn't have to equal the force that the structure below can sustain. Newton (Sir Isaac) never said anything of the sort.
Look carefully at that "safe hitting concrete" problem and you'll see that the forces that safe actually generates in the collision are far more than its static weight. It's the key to understanding the progressive collapse of the floors and the comminution of the concrete, IMO.
Einsteen - It seems like you're trying to assert symmetry where it doesn't exist.
"Complete" this and "total" that.
This wasn't a pristine lab experiment, it was a working office building. Symmetry doesn't exist in the reality, it's a first-cut approximation at best of what was there and what happened.
If you insist on total symmetry, you'll overlook the real phenomena that allowed the collapse to happen.
The damage was done mostly on the side hit, and asymmetrical load redistribution caused failures in specific places, not failures to general classes - i.e., not all the floor trusses failed simultaneously, not all the perimeter columns buckled at the same rate or fell outward at the same time.
If all loads were symmetrical, the central core might've remained standing, but that's like doing a computer simulation of a pencil standing on its tip - assuming perfect symmetry, it won't fall over, according to the computer model.
In reality, things happened piecemeal. (It'd be astronomically-improbable that everything happened at the same time.) So chunks of floor detached on one side of the core and didn't on the other side(s), leading to asymmetrical horizontal loads that they weren't designed for.
Ironically, simultaneous detonations in a CD would tend to yield greater symmetry in the collapse of the towers, so we'd have found more evidence of symmetry in the rubble pile. The fact that it was as random as it was is actually evidence that nothing symmetrical or controlled brought the towers down.
OK, I see. Yes I am very familiar with this phenomena. There is a train depot near a park where I go where you can sometimes hear this "collision front" propagate down the train cars when a train engine first couples to them and pushes them back.
I am very surprised (and a little disappointed) that you think this has any relevance to the puzzle of the progressive nature of the WTC collapse, with its perimeter columns blowing out laterally floor by floor.
QUOTE (DBB+)
In empirical science, there is no proof. There is only the ability to compare hypotheses, with of course, preference given to those hypotheses which do not contradict well established principles such a Newton's laws. The crush-down equation is Newton's laws, applied in a one-dimensional fashion. The same equation will work for the rail cars, with different parameters, of course. The same equation, applied in a time-reversed sense, works for rockets.
Isn't that enough evidence for you? I suppose nothing ever will be...
To be honest, I do not think you are being serious here... A little joke at my expense?
Isn't that enough evidence for you? I suppose nothing ever will be...
To be honest, I do not think you are being serious here... A little joke at my expense?
QUOTE (David B. Benson+Jun 24 2007, 12:55 AM)
Isn't that enough evidence for you? I suppose nothing ever will be...
He has no frame of reference. There is no gravity on planet conspiratoid.
He has no frame of reference. There is no gravity on planet conspiratoid.
QUOTE (wcelliott+Jun 23 2007, 04:47 PM)
No, I just say that when the floor has too much weight on it, it collapses, and when it collapses, it drops the load that made *it* collapse onto the floor below it.
By whatever mechanism/definition of "collapse" you feel reasonable, floors do *collapse*, and when they do, they drop their load to the next-lower floor.
Which itself collapses, in turn.
Maybe they're stupid, too.
You are still either ducking or missing the point. Or, perhaps, there's a language problem.
Not only don't I doubt that, if you could get floors collapsing, the collapsing would continue, I have written about this, myself, in this forum. Indeed, does not the chicken wire WTC plus aluminum foil analogy make this clear? But what about the columns? They will not collapse just because you say "boo".
I'm also well aware that floor panels helped to stabilize the columns. However, stability did not come just from the floor panels, and even if you used, say, balsa wood "floors" instead of aluminum foil "floors" in the chicken wire model, I think you know perfectly well that collapsing those "floors" in the manner we are discussing will not cause the chicken wire to collapse.
Now that you understand the point, do tell us if I am being presumptuous, and that your engineering intuition tells you that the chicken wire "columns" would collapse, also.
QUOTE
But what about the columns? They will not collapse just because you say "boo"
No, they'll collapse regardless of whatever either of us say, all on their own. They're unstable, and they can't support themselves. This is the problem with tinkertoy "models" of the WTC, they aren't to-scale.
Balsa wood floors? Is that balsa wood 600x thinner than the floor's width? If not, it's grossly overbuilt. The concrete floors were 4" thick, and 208' on each side.
The perimeter columns were heavy, but they were also relatively thin compared to their width and height. Don't take my word for it, just look at the videos, the floors fall before the walls, and the walls splay outward and break apart. Calculate the tension on the welds holding them together as they lean outward.
Metamars, just one of those long floor trusses would weigh over 40,000 lbs. You don't think that it has the energy, after falling a dozen feet or so, to break a core column splice or the bolts on a perimeter column splice? What about two or three of those floor trusses falling together?
Arthur
Arthur
And if the perimeter brackets failed before the core brackets, then the weight of the floor would be pulling the core columns outward as well as down. The core wasn't designed to simultaneously provide support to the load above and resist being pulled apart by the lateral weight of the part of the floor still attached, dangling from the core.
It's more similar to the "standing on the soda can and tapping its side" situation than anything having to do with chickenwire.
It's more similar to the "standing on the soda can and tapping its side" situation than anything having to do with chickenwire.
QUOTE (David B. Benson+Jun 24 2007, 12:55 AM)
The crush-down equation is Newton's laws, applied in a one-dimensional fashion. The same equation will work for the rail cars, with different parameters, of course. The same equation, applied in a time-reversed sense, works for rockets, with still different parameters.
It is, but there is also a law that says if you crush a story the crushing force works throughout the building.
It is, but there is also a law that says if you crush a story the crushing force works throughout the building.
QUOTE
It is, but there is also a law that says if you crush a story the crushing force works throughout the building
The force that *can* work throughout the structure, *once it gets to the structure*, does work through the structure. The other fraction of the force accelerates mass and damages frangible materials along the way.
Visualize a bank safe from the 100th floor plummeting through the floors - Some of it's kinetic energy is delivered to the floor structure (making a "BANG!" that'll be heard at ground level almost instantly due to the speed of sound in steel being 20,000 fps), some of it will just be smashing a hole in the concrete (accelerating the previously stationary concrete to the safe's current speed), and the rest of it just keeps accelerating the safe.
The force of the falling stuff doesn't have to equal the force that the structure below can sustain. Newton (Sir Isaac) never said anything of the sort.
Look carefully at that "safe hitting concrete" problem and you'll see that the forces that safe actually generates in the collision are far more than its static weight. It's the key to understanding the progressive collapse of the floors and the comminution of the concrete, IMO.
QUOTE (einsteen+Jun 24 2007, 10:21 AM)
It is, but there is also a law that says if you crush a story the crushing force works throughout the building.
Really?
Why then when a typical CD is performed all the crushing is done at the point where the building hits the ground?
In this case the STRONGEST floors are being crushed first, yet the WEAKER top floors always seem to WAIT THEIR TURN.
Arthur
Really?
Why then when a typical CD is performed all the crushing is done at the point where the building hits the ground?
In this case the STRONGEST floors are being crushed first, yet the WEAKER top floors always seem to WAIT THEIR TURN.
Arthur
QUOTE (adoucette+Jun 24 2007, 03:53 PM)
Really?
Why then when a typical CD is performed all the crushing is done at the point where the building hits the ground?
In this case the STRONGEST floors are being crushed first, yet the WEAKER top floors always seem to WAIT THEIR TURN.
Arthur
Are you sure ?
If you place charges on several levels, the whole building comes down as a whole and it gives the optical illusion that the floors crush from the bottom to the top because the relative distance between the floors remains the same, like you turn a building into a liquid. When you implode from the bottom floors it depends on the strength of the building, if it is too strong it will fail (because energy is transferred, maybe one of the wekaer upper stories will break or damage partly), if it is weaker then a total shockwave breaks the whole building and then you get the same effect as the first one.
Why then when a typical CD is performed all the crushing is done at the point where the building hits the ground?
In this case the STRONGEST floors are being crushed first, yet the WEAKER top floors always seem to WAIT THEIR TURN.
Arthur
Are you sure ?
If you place charges on several levels, the whole building comes down as a whole and it gives the optical illusion that the floors crush from the bottom to the top because the relative distance between the floors remains the same, like you turn a building into a liquid. When you implode from the bottom floors it depends on the strength of the building, if it is too strong it will fail (because energy is transferred, maybe one of the wekaer upper stories will break or damage partly), if it is weaker then a total shockwave breaks the whole building and then you get the same effect as the first one.
QUOTE (einsteen to adoucette+Jun 24 2007, 04:34 PM)
Are you sure ?
If you place charges on several levels, the whole building comes down as a whole and it gives the optical illusion that the floors crush from the bottom to the top because the relative distance between the floors remains the same, like you turn a building into a liquid. When you implode from the bottom floors it depends on the strength of the building, if it is too strong it will fail (because energy is transferred, maybe one of the wekaer upper stories will break or damage partly), if it is weaker then a total shockwave breaks the whole building and then you get the same effect as the first one.
Hi einsteen!
That's why in typical CD cases the main columns/pillars are 'explosively sectioned/weakened at the same time to REMOVE the STIFFNESS and strength which might cause the building to 'topple' instead of crush from bottom up as the main mass of floors and secondary support columns/pillars fall straight down.
HOWEVER, in the WTC cases, the main columns were essentially BYPASSED by the internal floor structures collapsing and leaving the walls/columns vulnerable and weak WHICH WAS THEIR DESIGN WEAKNESS.....so they COULD NOT have 'exhibited' any such STIFFNESS or strength characteristics/function AS FAR AS THE INNER FLOOR COLLAPSE WENT. So in that case it was not necessary to 'pre-section' those columns like you would have to do in a typical CD....because the columns were INEFFECTUAL ANYWAY once the internal collapse started.
Its like if a typical CD concentrated only on removing all the floor-to-wall connections and letting the innards crumble down AND LEAVING THE COLUMNS/PILLARS STANDING (depending on their heights/slenderness ratios etc....which in the case of WTC were TOO TALL and unstable AS DESIGNED to withstand self-leverage......unlike concrete columns/pillars, which have a greater ability in that aspect....
....which is why PROPER CONCRETE COLUMN/CORE STRUCTURES are once again being recommended for tall structures.
Forward to the past, heh! hehehe.
Cheers all!
RC.
.
If you place charges on several levels, the whole building comes down as a whole and it gives the optical illusion that the floors crush from the bottom to the top because the relative distance between the floors remains the same, like you turn a building into a liquid. When you implode from the bottom floors it depends on the strength of the building, if it is too strong it will fail (because energy is transferred, maybe one of the wekaer upper stories will break or damage partly), if it is weaker then a total shockwave breaks the whole building and then you get the same effect as the first one.
Hi einsteen!
That's why in typical CD cases the main columns/pillars are 'explosively sectioned/weakened at the same time to REMOVE the STIFFNESS and strength which might cause the building to 'topple' instead of crush from bottom up as the main mass of floors and secondary support columns/pillars fall straight down.
HOWEVER, in the WTC cases, the main columns were essentially BYPASSED by the internal floor structures collapsing and leaving the walls/columns vulnerable and weak WHICH WAS THEIR DESIGN WEAKNESS.....so they COULD NOT have 'exhibited' any such STIFFNESS or strength characteristics/function AS FAR AS THE INNER FLOOR COLLAPSE WENT. So in that case it was not necessary to 'pre-section' those columns like you would have to do in a typical CD....because the columns were INEFFECTUAL ANYWAY once the internal collapse started.
Its like if a typical CD concentrated only on removing all the floor-to-wall connections and letting the innards crumble down AND LEAVING THE COLUMNS/PILLARS STANDING (depending on their heights/slenderness ratios etc....which in the case of WTC were TOO TALL and unstable AS DESIGNED to withstand self-leverage......unlike concrete columns/pillars, which have a greater ability in that aspect....
....which is why PROPER CONCRETE COLUMN/CORE STRUCTURES are once again being recommended for tall structures.
Forward to the past, heh! hehehe.
Cheers all!
RC.
.
Thanks RC,
I admit that I don't know much about real CDs, trying to find info on the net is very difficult and it seems really a on-the-job learned skill.
Yes, the theory about that complete bypassing of the columns would energetically much more advantageous than a total crush. BUT you also have to keep in mind that after initiation the complete block, resp M14, M29 need to contribute its kinetic energy. If columns are not crushed you have to admit that it also doesn't happen for that top block, then those floors need to be detached from that block which IMO is ridiculous because if you place a building with the same construction as the Norths towers upper 14 stories directly on ground zero and drop it then all those floors should be detached. A complete skeleton is also not what we observe afterwards, maybe a few strong lower floors and a few mikado sticks. An alternative explanation is that the floors really fell first and later the rest, i.e. the visible outside collapse is after those floor fell, I don't believe it and that's also not consistent with the seismic activity
And don't forgot that the leading theoretical global collapse models all take into account a complete crushing, they don't describe a bypass. A total crush is most consistent with reality, although in a E1-model
I admit that I don't know much about real CDs, trying to find info on the net is very difficult and it seems really a on-the-job learned skill.
Yes, the theory about that complete bypassing of the columns would energetically much more advantageous than a total crush. BUT you also have to keep in mind that after initiation the complete block, resp M14, M29 need to contribute its kinetic energy. If columns are not crushed you have to admit that it also doesn't happen for that top block, then those floors need to be detached from that block which IMO is ridiculous because if you place a building with the same construction as the Norths towers upper 14 stories directly on ground zero and drop it then all those floors should be detached. A complete skeleton is also not what we observe afterwards, maybe a few strong lower floors and a few mikado sticks. An alternative explanation is that the floors really fell first and later the rest, i.e. the visible outside collapse is after those floor fell, I don't believe it and that's also not consistent with the seismic activity
And don't forgot that the leading theoretical global collapse models all take into account a complete crushing, they don't describe a bypass. A total crush is most consistent with reality, although in a E1-model
QUOTE
Yes, the theory about that complete bypassing of the columns would energetically much more advantageous than a total crush. BUT you also have to keep in mind that after initiation the complete block, resp M14, M29 need to contribute its kinetic energy. If columns are not crushed you have to admit that it also doesn't happen for that top block, then those floors need to be detached from that block which IMO is ridiculous because if you place a building with the same construction as the Norths towers upper 14 stories directly on ground zero and drop it then all those floors should be detached. A complete skeleton is also not what we observe afterward, maybe a few strong lower floors and a few mikado sticks. An alternative explanation is that the floors really fell first and later the rest, i.e. the visible outside collapse is after those floor fell, I don't believe it and that's also not consistent with the seismic activity
Einsteen - It seems like you're trying to assert symmetry where it doesn't exist.
"Complete" this and "total" that.
This wasn't a pristine lab experiment, it was a working office building. Symmetry doesn't exist in the reality, it's a first-cut approximation at best of what was there and what happened.
If you insist on total symmetry, you'll overlook the real phenomena that allowed the collapse to happen.
The damage was done mostly on the side hit, and asymmetrical load redistribution caused failures in specific places, not failures to general classes - i.e., not all the floor trusses failed simultaneously, not all the perimeter columns buckled at the same rate or fell outward at the same time.
If all loads were symmetrical, the central core might've remained standing, but that's like doing a computer simulation of a pencil standing on its tip - assuming perfect symmetry, it won't fall over, according to the computer model.
In reality, things happened piecemeal. (It'd be astronomically-improbable that everything happened at the same time.) So chunks of floor detached on one side of the core and didn't on the other side(s), leading to asymmetrical horizontal loads that they weren't designed for.
Ironically, simultaneous detonations in a CD would tend to yield greater symmetry in the collapse of the towers, so we'd have found more evidence of symmetry in the rubble pile. The fact that it was as random as it was is actually evidence that nothing symmetrical or controlled brought the towers down.
QUOTE (einsteen+Jun 24 2007, 11:34 AM)
If you place charges on several levels, the whole building comes down as a whole and it gives the optical illusion that the floors crush from the bottom to the top because the relative distance between the floors remains the same,
Its an OPTICAL ILLUSION???
ROTFLMAO
Shirley, You jest?
Arthur
Its an OPTICAL ILLUSION???
ROTFLMAO
Shirley, You jest?
Arthur
QUOTE (lozenge124+Jun 24 2007, 01:09 AM)
I am very surprised (and a little disappointed) that you think this has any relevance to the puzzle of the progressive nature of the WTC collapse, with its perimeter columns blowing out laterally floor by floor.
Yes, it is relevant, but somewhat less so than I first thought. The problem is the rail cars themselves are not be directly accelerated by the force of gravity, while3 in the towers the crushed floors were directly subject to the force of gravity. In more detail, let M be the mass of the weights in the pan and m the mass of each rail car. The accelerating force is constant,
F = Mg
Applied to the first rail car, the acceleration is given by solving for a in
F = (M+m)a
After the first rail car inelastically collides with the second, the acceleration is given by solving for a' in
F = (M+2m)a'
so a' is less than a. Repeat for all n rail cars.
However, except for this change of acceleration after each inelastic collision, the rest of Greening's equations are appropriate here.
Obviously this little model has nothing to do with perimeter columns (only some of which are laterally ejected). Indeed this rail car model consumes relatively little energy without something more impressive than Velcro to crush.
Yes, it is relevant, but somewhat less so than I first thought. The problem is the rail cars themselves are not be directly accelerated by the force of gravity, while3 in the towers the crushed floors were directly subject to the force of gravity. In more detail, let M be the mass of the weights in the pan and m the mass of each rail car. The accelerating force is constant,
F = Mg
Applied to the first rail car, the acceleration is given by solving for a in
F = (M+m)a
After the first rail car inelastically collides with the second, the acceleration is given by solving for a' in
F = (M+2m)a'
so a' is less than a. Repeat for all n rail cars.
However, except for this change of acceleration after each inelastic collision, the rest of Greening's equations are appropriate here.
Obviously this little model has nothing to do with perimeter columns (only some of which are laterally ejected). Indeed this rail car model consumes relatively little energy without something more impressive than Velcro to crush.
QUOTE (David B. Benson+Jun 24 2007, 12:55 AM)
In empirical science there is no proof. There is only the ability to compare hypotheses, with of course, preference given to those hypotheses which do not contradict well established principles such a Newton's laws. The crush-down equation is Newton's laws, applied in a one-dimensional fashion. The same equation will work for the rail cars, with different parameters, of course. The same equation, applied in a time-reversed sense, works for rockets, with still different parameters.
lozenge124 --- This is not a joke, although it does need correcting with regard to the rail cars as in my just previous post.
lozenge124 --- This is not a joke, although it does need correcting with regard to the rail cars as in my just previous post.
QUOTE (wcelliott+Jun 24 2007, 03:25 AM)
No, they'll collapse regardless of whatever either of us say, all on their own. They're unstable, and they can't support themselves. This is the problem with tinkertoy "models" of the WTC, they aren't to-scale.
QUOTE (NIST faq+)
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.
When did any troother back up any outlandish statement with any sort of evidence?
The NIST report restricted itself to the INITIATING CAUSE of the collapse, not the nature of what happened after the collapse began.
I'm applying simple physics and my 30 years' experience in design engineering to the problem of what happened next.
I don't consider what I've stated as either "pancaking" or "bagelling", both concepts assert some form of symmetry, which I've already stated is right out the window in the real-world WTC collapse.
When did any troother back up any outlandish statement with any sort of evidence?
The NIST report restricted itself to the INITIATING CAUSE of the collapse, not the nature of what happened after the collapse began.
I'm applying simple physics and my 30 years' experience in design engineering to the problem of what happened next.
I don't consider what I've stated as either "pancaking" or "bagelling", both concepts assert some form of symmetry, which I've already stated is right out the window in the real-world WTC collapse.
Well Bazant et al, disagree with your tortured interpretation of the NIST faq, and on this at least I have to say I agree with them:
Learn how to read before you call someone a jackass.
I didn't say that that the floors fell *BEFORE* the building collapsed, I was describing what happened AFTER THE COLLAPSE INITIATED.
As for the perimeter walls remaining standing after the collapse initiated, they didn't. Look at the videos. The floors dropped, then the outer columns fell away.
They weren't designed to stand on their own, nor were the cores.
As I've already described several times, it was the asymmetrical forces acting on the core columns that led to their collapse, but the perimeter columns were doomed as soon as the floors holding them vertical fell away.
They leaned over and the welds holding them together failed, and sections fell piecemeal.
That's in every video of the collapse, all you have to do is open your eyes and quit lying to yourself about what you're seeing.
Incidentally, I reported you for your language.
Learn how to read before you call someone a jackass.
I didn't say that that the floors fell *BEFORE* the building collapsed, I was describing what happened AFTER THE COLLAPSE INITIATED.
As for the perimeter walls remaining standing after the collapse initiated, they didn't. Look at the videos. The floors dropped, then the outer columns fell away.
They weren't designed to stand on their own, nor were the cores.
As I've already described several times, it was the asymmetrical forces acting on the core columns that led to their collapse, but the perimeter columns were doomed as soon as the floors holding them vertical fell away.
They leaned over and the welds holding them together failed, and sections fell piecemeal.
That's in every video of the collapse, all you have to do is open your eyes and quit lying to yourself about what you're seeing.
Incidentally, I reported you for your language.
Ah, but you are backing away from your thought experiment! Remember the one that had UPS delivering gravel to a WTC floor until it collapsed? And then you said:
So are you no longer prepared to stand behind this claim that the floors "were what held the perimeter wall columns vertical, and when they were no longer being held vertical they fell over"?
I enjoy watching you gentlemen squirm and backtrack as soon as you are pressed a little for some substantive backing of statements.
And by the way, I usually try to avoid foul language, but unfortunately, when subjected to a barrage of ad hominems and insults like CDidiot, troofer, etc... I will occasionally respond in kind!
PS. thanks for the feedback! "belligerent" 2x'L's no 'A'
I'm not opposed to using simplifying assumptions for first-order approximations, but in this instance, the phenomenology that led to the collapse initiation and the subsequent progressive collapse are both linked inextricably to the asymmetry of the circumstances.
As I attempted to illustrate with my "six men holding a telephone pole" example, weaker supports fail first, leading to an accelerating degeneration of the situation. It's this acceleration that makes the collapse initiation appear "sudden". It wasn't sudden at all, it started out slow with twenty minutes of buckling perimeter columns and floors pulling away from their perimeter support brackets.
One could (and I've argued, should) include the collapse-rate starting when the perimeter columns started bending inwards, with the collapse rate plotted in a log-linear scale to capture the initial part of the collapse. Even a descent rate of 0.01mm/hour is already an unsustainable rate for a building designed to remain standing indefinitely. I've criticized people I otherwise admire for making the oversimplifying assumption that "T-Zero" began only a few seconds before the top floor hit the street. "T-Zero" was at least twenty minutes earlier, by my accounting, the rate was just too slow to see on videos.
There is also an inevitable "zipper" effect when one structure/bracket fails, which leads to adjacent structures/brackets failing, and symmetry arguments can't recognize this phenomenon. (That's basically what I was trying to illustrate with the "telephone pole" example.)
Other asymmetry leads to cores being pulled sideways by floors brackets that haven't completely released yet on one side as much as they have on other sides. This is to be expected, and it's obviously a mode that the core wasn't designed for and one that would clearly lead to buckling of the core columns. If you assume symmetry, then you have the same loads on all sides of the core from all parts of the same floor either still being attached or all having released simultaneously (as a CD would do). Real-world, not a chance that'll happen, and the result is an asymmetrical side force that makes core column buckling inevitable.
Specific details about what happened when are pretty worthless, IMO. Once the buildings were hit with aircraft and they caught fire, they were doomed. What happened in which order is basically an academic exercise, but I've stated my best-guess and have backed it up with common-sense/plain-English explanations to keep the underlying phenomena easy to grasp. I personally think it's a bad idea to frame an argument in differential equations (although I've been criticized for not doing so by people who don't want anyone to actually understand the truth), as it leads inevitably to arguing about what number to pick for which variable, and 99% of the readers aren't going to delve into the equations any more than the OJ jury bothered listening to the DNA evidence. I take the criticism as a tactic to try to get me to make my arguments less easy to follow.
I take that as evidence that I'm doing things the right way, and it's killing them.
Not at all, the point of the thought experiment was to demonstrate that a building could collapse progressively without any explosives or fire at all.
It was argued by various CDiots that a progressive collapse was impossible without explosives. I showed how it could be done with gravel.
I wasn't suggesting that the aircraft were laden with gravel, if that's your next point.
It was simply to illustrate how once a floor collapses, it causes other floors beneath it to collapse in-turn. The weight that one floor can't support ends up on the floor beneath, and it can't support that weight, either.
Etc., to the ground.
Not at all, the point of the thought experiment was to demonstrate that a building could collapse progressively without any explosives or fire at all.
It was argued by various CDiots that a progressive collapse was impossible without explosives. I showed how it could be done with gravel.
I wasn't suggesting that the aircraft were laden with gravel, if that's your next point.
It was simply to illustrate how once a floor collapses, it causes other floors beneath it to collapse in-turn. The weight that one floor can't support ends up on the floor beneath, and it can't support that weight, either.
Etc., to the ground.
Still with the name calling I see! It doesn't help your case.
All you demonstrated with the gravel, was a progressive collapse of the floors. The core and perimeter structures would still be standing.
RC:
Sure the floors imparted some lateral stability to the perimeter walls, in particular in high wind situations, but do you believe that absent the floors, they would just "fall down"?
I am not claiming otherwise, but some proof would be nice.
All I'd *intended* to demonstrate with the gravel was a progressive collapse.
You should read my "symmetry" comments to understand why the core and perimeter structures wouldn't remain standing, I've explained that within the last page or so.
Einsteen -
The reason is that the structure can't convey any more force to the ground than it's maximum design strength, but the forces being generated by the falling materials during impact are many times that amount. The differences in the forces that are being generated during the collapse and the forces that the ground "feels" during the collapse are going into the destruction of the stuff in the crush zone and the acceleration of the material towards the ground. That last part of the energy is kinetic energy and won't be felt until the stuff hits the ground.
Rumble-rumble-rumble-THUD!!!!
Maybe this will help - If something free-falls 10 feet and you decelerate it uniformly back to zero velocity velocity in two feet (12' total distance), how many g's did it take in that last 2' feet to stop the falling object?
Ans: 6gs --- five to decelerate, plus one for gravity (which doesn't go away).
So if one floor falls ten feet and lands on 2 feet of crushable material, how much force does that one falling floor exert on the floor beneath it? (Assume each floor weighs 1.5million pounds.)
Hope this helps.
This is true enough, and when the forces due to sudden accelerations are concentrated over small areas, you get instantaneous pressures that exceed the materials' strength, and in the case of concrete, the concrete turns to dust.
Applying that 10:2 >>> 6gs to a deceleration distance of 1/2" and calculate what happens when concrete falls 11'11.5" and attempts to stop in a half-inch, then apply that force over the contact area of what you'd expect a chunk of concrete hitting randomly would be expected to hit a flat surface, and compare the pressure within that contact area to the compression strength of lightweight concrete (like used in the floors of the WTC.)
And while the instantaneous forces far exceed anthing the WTC floors were designed for, the forces transmitted through the structure are limited to the ultimate strength of the WTC structure itself. The differences are applied to accelerating the floor material downward and crushing it to dust.
As we saw in the WTC videos.
Hi loz124!
Not 'some', but 'critical' lateral support, hehehe.
Just ask a Scottish Caber(pole) Tosser why he has to keep moving the fulcrum point (himself!) in order to keep a simple POLE upright.
And anyway, with all that oscillation/vibration/asymmetry induced on the 'FREE ENDS' of the lower section columns when the top 'tie in' system (hat truss) effectively separated at initial collapse, the whole shebang was 'ringing' and 'wobbling' like a bell (not to mentioned that humongous crash/sway when the jets hit and the fuel exploded).
No 'free' steel ends so high and heavy and slender will hold position under even a fraction of these circumstances....and will eventually fall from their own self-leverage due to their own unrestrained WEIGHT and instability.
Add to that the 'pressure waves' of internal debris falls and expelled air, and you will quickly see that they could NOT stand.
Besides, the very CONSTRUCTION PROCESS showed the NECESSITY EVEN AT LOWER LEVELS of the floors as support structures, or else they would have been able to raise the PERIMETER walls all the way up MUCH QUICKER than they did because they had to construct the 'floor support' to KEEP PACE with those perimeter structures.
Cheers!
RC.
.
RC,
I think it is best not to throw too many variables in there at once. The question was referring to a WTC tower prior to any plane impact - imagine a WTC tower prior to 9/11, on a day with low winds say, now we magically remove all the floors (without causing any damage).
What happens? Do the perimeter columns fall in on themselves? Does the whole tower topple over?
If you like, you can also answer this question - consider the same tower as above (floors removed, no damage). Now remove the hat truss and the core. Same questions, what happens to the perimeter structure?
Hi loz124!
Not 'some', but 'critical' lateral support, hehehe.
Just ask a Scottish Caber(pole) Tosser why he has to keep moving the fulcrum point (himself!) in order to keep a simple POLE upright.
And anyway, with all that oscillation/vibration/asymmetry induced on the 'FREE ENDS' of the lower section columns when the top 'tie in' system (hat truss) effectively separated at initial collapse, the whole shebang was 'ringing' and 'wobbling' like a bell (not to mentioned that humongous crash/sway when the jets hit and the fuel exploded).
No 'free' steel ends so high and heavy and slender will hold position under even a fraction of these circumstances....and will eventually fall from their own self-leverage due to their own unrestrained WEIGHT and instability.
Add to that the 'pressure waves' of internal debris falls and expelled air, and you will quickly see that they could NOT stand.
Besides, the very CONSTRUCTION PROCESS showed the NECESSITY EVEN AT LOWER LEVELS of the floors as support structures, or else they would have been able to raise the PERIMETER walls all the way up MUCH QUICKER than they did because they had to construct the 'floor support' to KEEP PACE with those perimeter structures.
Cheers!
RC.
.
Your caber tosser example applies more to the tower as a whole, not to individual perimeter columns. The columns are connected together with the spandrel plates in threes, and these sections are bolted (adjacent sections) and welded (above and below) to each other. You end up with one large "caber". I can see the shear stress on these connections coming under increased strain under lateral wind loads without the floors - but large enough to fall apart?
Vis a vis your construction process remark - from a purely logistical standpoint, it wouldn't make much sense to raise the perimeter walls up faster than the floors. This would have required the cranes for example to keep pace with the perimeter columns, and all raised material to travel much further (over the raised perimeter structure and down to the floor). Also much more difficult to assemble the pre-fabricated perimeter structures and bolt them together. So I don't think any conclusions can be drawn from this.
...whereas Jowenko based his OPINION on what a carefully edited video LOOKED LIKE and DID NOT KNOW any other of the facts surrounding 7(he is a fool to state he is certain it was CD, the most he could say was that it LOOKED LIKE a CD).
Yeah Grumpy. In fact, they showed him the edited video without telling him it was WTC 7 until AFTERWARDS. IOWs, he didn't even know what he was looking at, yet came up with his conclusion that it was CD. He was surprised when they told him, and didn't he change his mind later after learning of other conditions?
Well you just answered my question in the last post. Not only didn’t they show Jowenko the whole video, but you seem to be unfamiliar with it as well.
Don’t you think that is somewhat dishonest?
Are you nuts, Jowenko had seen several videos, the construction of the building etc. I've spent a week to translate the complete interview in English and put it on youtube. What was your question ?
I'm just asking, I really don't know the answer myself, but isn't the *energy* coupled from one medium to the next proportional to the *square* of the coupling coefficient (=1-reflection coefficient)?
In other words, if the reflection coefficient is 0.662, then the coupling coefficient would be (1-0.662) = 0.338, and the *energy* coupled from the steel to the concrete would be 0.338^2 or .114?
I get confused because this is worked one way with light and another with microwave waveguides, but I think the reflection coefficient deals with amplitudes, and the energy is proportional to the square of the amplitude.
Correct me if I'm wrong...
The other point to remember is that this attenuation concatenates with other places where the impedance is mismatched, so it isn't just between the steel and the bathtub, but the tower and the main lobby and the main lobby and the basement... All those impedance mismatches have to be multiplied in series.
(That much I'm sure about.)
Hi loz124!
Why do you unilateraly/arbitrarily 'bound' the caber tossing example to apply ONLY to the WHOLE building?
ANY sufficiently long/heavy LEVER state will produce/amplify DESTRUCTIVE forces at its 'fulcrum' COMMENSURATE with its scale.
That is the lever/wedge principle AT ALL SCALES. No?
So it's fair to say that at the scale of BOLTS/WELDS and the WOBBLING/OSCILLATING/SIDE-PRESSURED column sections would act to amplify the forces at THEIR fulcrums (at various lengths and times/durations).
And as for removing floors in the INTACT tower structures.....you should read the old threads where the troofers themselves maintained, and presented evidence in supprt, that the floors were INTEGRAL to load distribution/sharing between the perimeter walls and core structure so that NEITHER was put into EXCURSION from their designed parameters (which were exceeded anyway in the event due to impact/fire/load-redistribution/local collapse etc for which the structures were HOPELESSLY 'underdesigned'....but I suppose they could not foresee the catalogue of failures of fireproofing, loss of sprinkler/manned firefighting systems, and FLOOR TRUSS FAILURES involved in LOCAL COLLAPSE and FLOOR, BOLT-WELD vulnerabilies and FAILURES under the subsequent dynamic loads involved in GLOBAL COLLAPSE thereafter etc!).
And if we DID remove 5-10 floors worth of lateral support for the inner/outer walls, as you visualised could be done without 'harm', consider that any forces on the perimeter and 'core structures/faces would THEN eventually be CONCENTRATED at that ONE 'point' in the whole height where the forces were NOT 'equalised/damped' and so EVERYTHING would effectively have been 'fulcruming' at that 'floorless point'....with the result that not only would the TOP section begin swaying DESTRUCTIVELY as 'harmonic motion' ACCUMULATED the forces to extreme OFF-axis movement beyond the design parameters, but it would also be destroying LOCAL 'piecemeal' connections of the CORE structure beginning with the weakest and overloading the next strongest etc IN QUICK SUCCESSION.
And of course, IF the perimeter and 'core' steelwork COULD have progressed WITHOUT the floors to brace them (as you maintain), then what's to stop the builders from using THEM as the CRANE STRUCTURE/BASES as they 'construct themselves' and thus would save much time and money using/extending 'kangaroo cranes' for the job?
So I think that if they could have got away with it they would have. But anyway, even the documents/evidence/design statements MAKE QUITE EXPLICITLY CLEAR even before these events, that the whole buildinbg was INTERDEPENDENT with every OTHER part of it....which is the MINIMALIST feature of the structure that allowed them to have all that EMPTY/UNSUPPORTED FLOOR-SPACE between the inner and outer 'tubes' that were both interconnected/dependent on each other VIA THE FLOORS at all stages....with the final TOP HAT TRUSS being the most STRONG 'floors' structure/levels serving not only for load transfer between perimeter and core BUT ALSO to functioning to 'tie up the loose ends' of the upper columns to prevent 'unzipping' LEVERAGE FORCES from ever building up (due to harmonic motion behaviour).
See?
Cheers all!
RC.
.
Hi RC,
I'll take that as a yes. Without the floors, you believe the perimeter columns would fall over being inherently stable.
I don't happen to agree with this. My feeling is that as the perimeter columns were designed to support both lateral and vertical loads (while the core was only designed for vertical loads), it would hold up better than that, especially in low wind situations; in a strong wind close to the max design parameters it might not fare as well, but the staggered system of bolting the perimeter sections together, and the angled corners of the towers, seems well enough thought out for the tower perimeter structure to be considered as one unit, not small individual "cabers" flapping individually.
Granted, as with your post, this is just my opinion unbacked by any hard evidence. (I do not have any statements/papers that consider this scenario).
But thanks for sharing your thoughts.
I'd like to add to Grumpy's statement. It isn't merely a LACK of evidence that explosives were used, it's the PRESENCE' of evidence that EXPLOSIVES WEREN'T USED.
The collapse happened in slow motion, starting with the bowing inward of the perimeter columns. That happened VERY SLOWLY, over the course of at least 20 MINUTES. No explosive works slowly. Not even thermite.
I'm late for work, so this will be a short subset of the actual list.
The other point to consider is that if it'd been planned, they'd have had to have planned it extraordinarily carefully, as much of the phenomena that we saw was to be expected, but only if you really understand how things work. If they'd have faked it, it would've ended up looking like something out of The Matrix.
The very things that made the troothers originally object to it as looking fishy have all been proved to be exactly what physics required. If the government had been involved in faking it, some committee would've made a wrong decision someplace and it would've ended up looking like what that committee thought it *ought* to look like, and it would've been wrong.
We've got over three hundred pages of examples of stuff that people *thought* looked wrong and none of those things panned out. The troothers still have no Smoking Gun. How many of those things would've ended up getting past a planning committee?
QUOTE (Bazant/Le/Greening/Benson paper+)
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.
By the way, what is your source for the claim that the WTC perimeter structure would collapse if the floors were removed? It is customary in this forum to back up statements, especially outlandish ones, with some type of evidence.
By the way, what is your source for the claim that the WTC perimeter structure would collapse if the floors were removed? It is customary in this forum to back up statements, especially outlandish ones, with some type of evidence.
QUOTE
It is customary in this forum to back up statements, especially outlandish ones, with some type of evidence.
When did any troother back up any outlandish statement with any sort of evidence?
The NIST report restricted itself to the INITIATING CAUSE of the collapse, not the nature of what happened after the collapse began.
I'm applying simple physics and my 30 years' experience in design engineering to the problem of what happened next.
I don't consider what I've stated as either "pancaking" or "bagelling", both concepts assert some form of symmetry, which I've already stated is right out the window in the real-world WTC collapse.
QUOTE (wcelliott+Jun 24 2007, 08:15 PM)
When did any troother back up any outlandish statement with any sort of evidence?
The NIST report restricted itself to the INITIATING CAUSE of the collapse, not the nature of what happened after the collapse began.
I'm applying simple physics and my 30 years' experience in design engineering to the problem of what happened next.
I don't consider what I've stated as either "pancaking" or "bagelling", both concepts assert some form of symmetry, which I've already stated is right out the window in the real-world WTC collapse.
Well Bazant et al, disagree with your tortured interpretation of the NIST faq, and on this at least I have to say I agree with them:
QUOTE (Bazant et al+)
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.
Without providing any kind of evidence for your speculations, you'll continue to look like a complete jackass!
Without providing any kind of evidence for your speculations, you'll continue to look like a complete jackass!
QUOTE (wcelliott+)
In any case, when the floors failed, they were what held the perimeter wall columns vertical, and when they were no longer being held vertical they fell over.
This is the claim you have made and should back up: remove the floors in a WTC tower, the perimeter and core structures are left standing - the perimeter columns then fall over by themselves.
This is the claim you have made and should back up: remove the floors in a WTC tower, the perimeter and core structures are left standing - the perimeter columns then fall over by themselves.
QUOTE
Well Bazant et al, disagree with your tortured interpretation of the NIST faq, and on this at least I have to say I agree with them
Learn how to read before you call someone a jackass.
I didn't say that that the floors fell *BEFORE* the building collapsed, I was describing what happened AFTER THE COLLAPSE INITIATED.
As for the perimeter walls remaining standing after the collapse initiated, they didn't. Look at the videos. The floors dropped, then the outer columns fell away.
They weren't designed to stand on their own, nor were the cores.
As I've already described several times, it was the asymmetrical forces acting on the core columns that led to their collapse, but the perimeter columns were doomed as soon as the floors holding them vertical fell away.
They leaned over and the welds holding them together failed, and sections fell piecemeal.
That's in every video of the collapse, all you have to do is open your eyes and quit lying to yourself about what you're seeing.
Incidentally, I reported you for your language.
Arthur,
Before you laugh at me here is a picture
of what I have in mind about real CDs combined
with what I know about physics of course I could
be wrong, in the 1st I mean that if the whole structure
falls with near-free fall each part of the building
falls with that speed, I'm sure you know what I mean,
aren't we playing games here sometimes....
The charges on higher levels are normally used for a more
complete collapse and more manageable pieces, easier cleaning
up, a collapse from the bottom will be a bigger mess
img link
WcElliot,
Symmetry,... of course not, but the leading
global collapse articles use the biggest symmetry ever,
we are talking about a first order model approximation.
Before you laugh at me here is a picture
of what I have in mind about real CDs combined
with what I know about physics of course I could
be wrong, in the 1st I mean that if the whole structure
falls with near-free fall each part of the building
falls with that speed, I'm sure you know what I mean,
aren't we playing games here sometimes....
The charges on higher levels are normally used for a more
complete collapse and more manageable pieces, easier cleaning
up, a collapse from the bottom will be a bigger mess
img link
WcElliot,
Symmetry,... of course not, but the leading
global collapse articles use the biggest symmetry ever,
we are talking about a first order model approximation.
QUOTE (wcelliott+Jun 24 2007, 08:55 PM)
Learn how to read before you call someone a jackass.
I didn't say that that the floors fell *BEFORE* the building collapsed, I was describing what happened AFTER THE COLLAPSE INITIATED.
As for the perimeter walls remaining standing after the collapse initiated, they didn't. Look at the videos. The floors dropped, then the outer columns fell away.
They weren't designed to stand on their own, nor were the cores.
As I've already described several times, it was the asymmetrical forces acting on the core columns that led to their collapse, but the perimeter columns were doomed as soon as the floors holding them vertical fell away.
They leaned over and the welds holding them together failed, and sections fell piecemeal.
That's in every video of the collapse, all you have to do is open your eyes and quit lying to yourself about what you're seeing.
Incidentally, I reported you for your language.
Ah, but you are backing away from your thought experiment! Remember the one that had UPS delivering gravel to a WTC floor until it collapsed? And then you said:
QUOTE
In any case, when the floors failed, they were what held the perimeter wall columns vertical, and when they were no longer being held vertical they fell over.
So are you no longer prepared to stand behind this claim that the floors "were what held the perimeter wall columns vertical, and when they were no longer being held vertical they fell over"?
I enjoy watching you gentlemen squirm and backtrack as soon as you are pressed a little for some substantive backing of statements.
And by the way, I usually try to avoid foul language, but unfortunately, when subjected to a barrage of ad hominems and insults like CDidiot, troofer, etc... I will occasionally respond in kind!
PS. thanks for the feedback! "belligerent" 2x'L's no 'A'
QUOTE
WcElliot,
Symmetry,... of course not, but the leading
global collapse articles use the biggest symmetry ever,
Symmetry,... of course not, but the leading
global collapse articles use the biggest symmetry ever,
I'm not opposed to using simplifying assumptions for first-order approximations, but in this instance, the phenomenology that led to the collapse initiation and the subsequent progressive collapse are both linked inextricably to the asymmetry of the circumstances.
As I attempted to illustrate with my "six men holding a telephone pole" example, weaker supports fail first, leading to an accelerating degeneration of the situation. It's this acceleration that makes the collapse initiation appear "sudden". It wasn't sudden at all, it started out slow with twenty minutes of buckling perimeter columns and floors pulling away from their perimeter support brackets.
One could (and I've argued, should) include the collapse-rate starting when the perimeter columns started bending inwards, with the collapse rate plotted in a log-linear scale to capture the initial part of the collapse. Even a descent rate of 0.01mm/hour is already an unsustainable rate for a building designed to remain standing indefinitely. I've criticized people I otherwise admire for making the oversimplifying assumption that "T-Zero" began only a few seconds before the top floor hit the street. "T-Zero" was at least twenty minutes earlier, by my accounting, the rate was just too slow to see on videos.
There is also an inevitable "zipper" effect when one structure/bracket fails, which leads to adjacent structures/brackets failing, and symmetry arguments can't recognize this phenomenon. (That's basically what I was trying to illustrate with the "telephone pole" example.)
Other asymmetry leads to cores being pulled sideways by floors brackets that haven't completely released yet on one side as much as they have on other sides. This is to be expected, and it's obviously a mode that the core wasn't designed for and one that would clearly lead to buckling of the core columns. If you assume symmetry, then you have the same loads on all sides of the core from all parts of the same floor either still being attached or all having released simultaneously (as a CD would do). Real-world, not a chance that'll happen, and the result is an asymmetrical side force that makes core column buckling inevitable.
Specific details about what happened when are pretty worthless, IMO. Once the buildings were hit with aircraft and they caught fire, they were doomed. What happened in which order is basically an academic exercise, but I've stated my best-guess and have backed it up with common-sense/plain-English explanations to keep the underlying phenomena easy to grasp. I personally think it's a bad idea to frame an argument in differential equations (although I've been criticized for not doing so by people who don't want anyone to actually understand the truth), as it leads inevitably to arguing about what number to pick for which variable, and 99% of the readers aren't going to delve into the equations any more than the OJ jury bothered listening to the DNA evidence. I take the criticism as a tactic to try to get me to make my arguments less easy to follow.
I take that as evidence that I'm doing things the right way, and it's killing them.
QUOTE (lozenge124+Jun 24 2007, 09:08 PM)
Ah, but you are backing away from your thought experiment! Remember the one that had UPS delivering gravel to a WTC floor until it collapsed? And then you said:
So are you no longer prepared to stand behind this claim that the floors "were what held the perimeter wall columns vertical, and when they were no longer being held vertical they fell over"?
I enjoy watching you gentlemen squirm and backtrack as soon as you are pressed a little for some substantive backing of statements.
And by the way, I usually try to avoid foul language, but unfortunately, when subjected to a barrage of ad hominems and insults like CDidiot, troofer, etc... I will occasionally respond in kind!
PS. thanks for the feedback! "belligerent" 2x'L's no 'A'
Hi loz124!
The old threads covered this aspect, mate! The floor structures as LATERAL STABILITY and LOAD TRANFER to 'core' ssystem was INTEGRAL to the design of the tube-in-tube design.
Reference to all the designs and the designers' comments in the old threads will show what wcelliot is talking about.
And since he is also talking of what happens AFTER initial collapse, he is saying that the 'unCAPPED' columns were vulnerable at their UPPER ends.
You see, the TOP box also included a HEAVY HAT TRUSS strcture that 'tied together' and 'capped' the upper ends of the columns when the towers were INTACT.
Once the upper hat truss 'tie-up' was compromised by local collapse, the lower section's columns were effectively no longer 'terminated' as a UNIT via anything that could tie up all the loose upper ends of the lower section. The unterminated/untied column ends could then be 'shoved aside' and 'oscillated' by the tumult of the top section falling into/against those loose ends....with the self-leveraging results we all saw....assisted by air expulsion pressure and debris sideways pressure
Please remeber to distinguish whether one is talking of INITIAL COLLAPSE FEATURES or PROGRESSIVE COLLAPSE FEATURES when saying 'aha, gotcha!'....because you may be talking at cross-purposes.
That UPA gravel delivery jest was meant to point out the VULNERABILIYTY of the floors to be effectively NEGATED as 'lateral support' for the wall structures ONCE THEY TOO WERE 'FREED' from the integral 'tie-in' required BY DESIGN via the HAT TRUSS which came down with the upper box section.
Cheers!
RC.
.
So are you no longer prepared to stand behind this claim that the floors "were what held the perimeter wall columns vertical, and when they were no longer being held vertical they fell over"?
I enjoy watching you gentlemen squirm and backtrack as soon as you are pressed a little for some substantive backing of statements.
And by the way, I usually try to avoid foul language, but unfortunately, when subjected to a barrage of ad hominems and insults like CDidiot, troofer, etc... I will occasionally respond in kind!
PS. thanks for the feedback! "belligerent" 2x'L's no 'A'
Hi loz124!
The old threads covered this aspect, mate! The floor structures as LATERAL STABILITY and LOAD TRANFER to 'core' ssystem was INTEGRAL to the design of the tube-in-tube design.
Reference to all the designs and the designers' comments in the old threads will show what wcelliot is talking about.
And since he is also talking of what happens AFTER initial collapse, he is saying that the 'unCAPPED' columns were vulnerable at their UPPER ends.
You see, the TOP box also included a HEAVY HAT TRUSS strcture that 'tied together' and 'capped' the upper ends of the columns when the towers were INTACT.
Once the upper hat truss 'tie-up' was compromised by local collapse, the lower section's columns were effectively no longer 'terminated' as a UNIT via anything that could tie up all the loose upper ends of the lower section. The unterminated/untied column ends could then be 'shoved aside' and 'oscillated' by the tumult of the top section falling into/against those loose ends....with the self-leveraging results we all saw....assisted by air expulsion pressure and debris sideways pressure
Please remeber to distinguish whether one is talking of INITIAL COLLAPSE FEATURES or PROGRESSIVE COLLAPSE FEATURES when saying 'aha, gotcha!'....because you may be talking at cross-purposes.
That UPA gravel delivery jest was meant to point out the VULNERABILIYTY of the floors to be effectively NEGATED as 'lateral support' for the wall structures ONCE THEY TOO WERE 'FREED' from the integral 'tie-in' required BY DESIGN via the HAT TRUSS which came down with the upper box section.
Cheers!
RC.
.
QUOTE
Ah, but you are backing away from your thought experiment!
Not at all, the point of the thought experiment was to demonstrate that a building could collapse progressively without any explosives or fire at all.
It was argued by various CDiots that a progressive collapse was impossible without explosives. I showed how it could be done with gravel.
I wasn't suggesting that the aircraft were laden with gravel, if that's your next point.
It was simply to illustrate how once a floor collapses, it causes other floors beneath it to collapse in-turn. The weight that one floor can't support ends up on the floor beneath, and it can't support that weight, either.
Etc., to the ground.
QUOTE (wcelliott+Jun 24 2007, 09:31 PM)
Not at all, the point of the thought experiment was to demonstrate that a building could collapse progressively without any explosives or fire at all.
It was argued by various CDiots that a progressive collapse was impossible without explosives. I showed how it could be done with gravel.
I wasn't suggesting that the aircraft were laden with gravel, if that's your next point.
It was simply to illustrate how once a floor collapses, it causes other floors beneath it to collapse in-turn. The weight that one floor can't support ends up on the floor beneath, and it can't support that weight, either.
Etc., to the ground.
Still with the name calling I see! It doesn't help your case.
All you demonstrated with the gravel, was a progressive collapse of the floors. The core and perimeter structures would still be standing.
RC:
Sure the floors imparted some lateral stability to the perimeter walls, in particular in high wind situations, but do you believe that absent the floors, they would just "fall down"?
I am not claiming otherwise, but some proof would be nice.
The acoustical impedance, Z, of a material is the density times the speed of sound.
mild steel: density=7848.3, speed=5960, Z(steel)=46,775,868
concrete: density=2322.9, speed 4100, Z(concrete)=9,523,890
Thus the acoustic reflection coefficient for the steel to concrete transition at the bottom of the Bathtub was R = 0.662. Thus only about one-third of the acoustic energy in the steel is transmitted into the concrete.
The is another impedance mismatch between the concrete and the underlying Manhattan schist, but it will be less pronounced. Anyway, I was only interested in the steel-concrete interface.
And by the way, as the Bathtub was 70 feet deep and, according to Wikipedia, the schist was 75 feet down, there was five feet of concrete in the bottom.
mild steel: density=7848.3, speed=5960, Z(steel)=46,775,868
concrete: density=2322.9, speed 4100, Z(concrete)=9,523,890
Thus the acoustic reflection coefficient for the steel to concrete transition at the bottom of the Bathtub was R = 0.662. Thus only about one-third of the acoustic energy in the steel is transmitted into the concrete.
The is another impedance mismatch between the concrete and the underlying Manhattan schist, but it will be less pronounced. Anyway, I was only interested in the steel-concrete interface.
And by the way, as the Bathtub was 70 feet deep and, according to Wikipedia, the schist was 75 feet down, there was five feet of concrete in the bottom.
QUOTE (lozenge124+Jun 24 2007, 09:45 PM)
Sure the floors imparted some lateral stability to the perimeter walls, in particular in high wind situations, but do you believe that absent the floors, they would just "fall down"?
Read about Euler buckling. When you are ready, I'll post a link to a useful site which describes practical column buckling.
Read about Euler buckling. When you are ready, I'll post a link to a useful site which describes practical column buckling.
QUOTE
All you demonstrated with the gravel, was a progressive collapse of the floors. The core and perimeter structures would still be standing.
All I'd *intended* to demonstrate with the gravel was a progressive collapse.
You should read my "symmetry" comments to understand why the core and perimeter structures wouldn't remain standing, I've explained that within the last page or so.
QUOTE (einsteen+Jun 24 2007, 04:03 PM)
Arthur,
Before you laugh at me here is a picture
of what I have in mind about real CDs combined
with what I know about physics of course I could
be wrong, in the 1st I mean that if the whole structure
falls with near-free fall each part of the building
falls with that speed, I'm sure you know what I mean,
aren't we playing games here sometimes....
The charges on higher levels are normally used for a more
complete collapse and more manageable pieces, easier cleaning
up, a collapse from the bottom will be a bigger mess
img link
I'm sure those means SOMETHING to you.
The FACT is I've seen (and you can too via the internet) DOZENS of large buildings taken down by explosives and IN MOST CASES, the majority of the explosives are set at the bottom and IN MANY CASES the building stays relatively intact as it gets crushed by the impact with the ground.
Now you can't use one or two examples of where the whole builiding deforms at the start as proof of your theory, but YOU CAN use the few examples of where it DOESN'T react the way you claim to show that the collapsing building does NOT transmit crushing forces more than a few stories.
Arthur
Before you laugh at me here is a picture
of what I have in mind about real CDs combined
with what I know about physics of course I could
be wrong, in the 1st I mean that if the whole structure
falls with near-free fall each part of the building
falls with that speed, I'm sure you know what I mean,
aren't we playing games here sometimes....
The charges on higher levels are normally used for a more
complete collapse and more manageable pieces, easier cleaning
up, a collapse from the bottom will be a bigger mess
img link
I'm sure those means SOMETHING to you.
The FACT is I've seen (and you can too via the internet) DOZENS of large buildings taken down by explosives and IN MOST CASES, the majority of the explosives are set at the bottom and IN MANY CASES the building stays relatively intact as it gets crushed by the impact with the ground.
Now you can't use one or two examples of where the whole builiding deforms at the start as proof of your theory, but YOU CAN use the few examples of where it DOESN'T react the way you claim to show that the collapsing building does NOT transmit crushing forces more than a few stories.
Arthur
QUOTE (lozenge124+Jun 24 2007, 09:45 PM)
....
.....
......
RC:
Sure the floors imparted some lateral stability to the perimeter walls, in particular in high wind situations, but do you believe that absent the floors, they would just "fall down"?
I am not claiming otherwise, but some proof would be nice.
Hi loz124!
Not 'some', but 'critical' lateral support, hehehe.
Just ask a Scottish Caber(pole) Tosser why he has to keep moving the fulcrum point (himself!) in order to keep a simple POLE upright.
And anyway, with all that oscillation/vibration/asymmetry induced on the 'FREE ENDS' of the lower section columns when the top 'tie in' system (hat truss) effectively separated at initial collapse, the whole shebang was 'ringing' and 'wobbling' like a bell (not to mentioned that humongous crash/sway when the jets hit and the fuel exploded).
No 'free' steel ends so high and heavy and slender will hold position under even a fraction of these circumstances....and will eventually fall from their own self-leverage due to their own unrestrained WEIGHT and instability.
Add to that the 'pressure waves' of internal debris falls and expelled air, and you will quickly see that they could NOT stand.
Besides, the very CONSTRUCTION PROCESS showed the NECESSITY EVEN AT LOWER LEVELS of the floors as support structures, or else they would have been able to raise the PERIMETER walls all the way up MUCH QUICKER than they did because they had to construct the 'floor support' to KEEP PACE with those perimeter structures.
Cheers!
RC.
.
.....
......
RC:
Sure the floors imparted some lateral stability to the perimeter walls, in particular in high wind situations, but do you believe that absent the floors, they would just "fall down"?
I am not claiming otherwise, but some proof would be nice.
Hi loz124!
Not 'some', but 'critical' lateral support, hehehe.
Just ask a Scottish Caber(pole) Tosser why he has to keep moving the fulcrum point (himself!) in order to keep a simple POLE upright.
And anyway, with all that oscillation/vibration/asymmetry induced on the 'FREE ENDS' of the lower section columns when the top 'tie in' system (hat truss) effectively separated at initial collapse, the whole shebang was 'ringing' and 'wobbling' like a bell (not to mentioned that humongous crash/sway when the jets hit and the fuel exploded).
No 'free' steel ends so high and heavy and slender will hold position under even a fraction of these circumstances....and will eventually fall from their own self-leverage due to their own unrestrained WEIGHT and instability.
Add to that the 'pressure waves' of internal debris falls and expelled air, and you will quickly see that they could NOT stand.
Besides, the very CONSTRUCTION PROCESS showed the NECESSITY EVEN AT LOWER LEVELS of the floors as support structures, or else they would have been able to raise the PERIMETER walls all the way up MUCH QUICKER than they did because they had to construct the 'floor support' to KEEP PACE with those perimeter structures.
Cheers!
RC.
.
If you look at the collapse of wtc7 and then especially the Naudet video, then if it is caused by a failue of one story you also see the effect that a complete shockwave goes throught the whole building. First you see the roof is horizontal, then it caves in a little bit, you see all floors cave in, I would say that at that moment the buiding then is broken on several levels. In the long Jowenko video he explains that there is also a technique in which you don't need charges on higher levels, you only have to cut (with a torch) the columns in a V shape, they are then still on top of each other, but if there is initiation you get more fall speed because they are already broken on the higher levels. But as I said I'm not sure about that total crush up, if you have a piece of material, very general, and drop it on a solid ground then why would the energy concentrate on the lower part?
QUOTE (einsteen+)
if you have a piece of material, very general, and drop it on a solid ground then why would the energy concentrate on the lower part?
QUOTE
if you have a piece of material, very general, and drop it on a solid ground then why would the energy concentrate on the lower part?
Einsteen -
The reason is that the structure can't convey any more force to the ground than it's maximum design strength, but the forces being generated by the falling materials during impact are many times that amount. The differences in the forces that are being generated during the collapse and the forces that the ground "feels" during the collapse are going into the destruction of the stuff in the crush zone and the acceleration of the material towards the ground. That last part of the energy is kinetic energy and won't be felt until the stuff hits the ground.
Rumble-rumble-rumble-THUD!!!!
Maybe this will help - If something free-falls 10 feet and you decelerate it uniformly back to zero velocity velocity in two feet (12' total distance), how many g's did it take in that last 2' feet to stop the falling object?
Ans: 6gs --- five to decelerate, plus one for gravity (which doesn't go away).
So if one floor falls ten feet and lands on 2 feet of crushable material, how much force does that one falling floor exert on the floor beneath it? (Assume each floor weighs 1.5million pounds.)
Hope this helps.
einsteen
One thing that puzzles me, how can Jowenko tell it was a CD by viewing one edited film clip, yet the CD experts who were on the scene don't see it that way???
Also, why did the Loose Change crew have to go to Sweden to finally find a real engineer to agree with them??? I guess all the American engineers were all in on it, huh???
http://11-settembre.blogspot.com/2007/02/w...old-photos.html
Good photos of the damage to 7
Grumpy
One thing that puzzles me, how can Jowenko tell it was a CD by viewing one edited film clip, yet the CD experts who were on the scene don't see it that way???
Also, why did the Loose Change crew have to go to Sweden to finally find a real engineer to agree with them??? I guess all the American engineers were all in on it, huh???
http://11-settembre.blogspot.com/2007/02/w...old-photos.html
Good photos of the damage to 7
Grumpy
Arthur,
A car is of course designed to save the people on board, maybe this train crash
is a nice alternative http://www.youtube.com/watch?v=FJ9LJybIfds
WC,
If material has a speed and needs to decelerate a force is needed indeed,
but you can also look at it in the reverse way, if is standing still then
give it an extreme acceleration, I think it is a matter of how much force
the material can handle and how much acceleration there is
A car is of course designed to save the people on board, maybe this train crash
is a nice alternative http://www.youtube.com/watch?v=FJ9LJybIfds
WC,
If material has a speed and needs to decelerate a force is needed indeed,
but you can also look at it in the reverse way, if is standing still then
give it an extreme acceleration, I think it is a matter of how much force
the material can handle and how much acceleration there is
QUOTE
I think it is a matter of how much force
the material can handle and how much acceleration there is
the material can handle and how much acceleration there is
This is true enough, and when the forces due to sudden accelerations are concentrated over small areas, you get instantaneous pressures that exceed the materials' strength, and in the case of concrete, the concrete turns to dust.
Applying that 10:2 >>> 6gs to a deceleration distance of 1/2" and calculate what happens when concrete falls 11'11.5" and attempts to stop in a half-inch, then apply that force over the contact area of what you'd expect a chunk of concrete hitting randomly would be expected to hit a flat surface, and compare the pressure within that contact area to the compression strength of lightweight concrete (like used in the floors of the WTC.)
And while the instantaneous forces far exceed anthing the WTC floors were designed for, the forces transmitted through the structure are limited to the ultimate strength of the WTC structure itself. The differences are applied to accelerating the floor material downward and crushing it to dust.
As we saw in the WTC videos.
Grumpy, I didn't know that. In on it ? If someone needs to say something about wtc7, what would you do ? If I was a cd expert in the US I also would say "no" even if you are 99% convinced that it is a CD. You don't know what happened there, you was not there, you didn't do it, you don't care, it is not your business. I would never say yes, the social pressure is extreme, there is a risk to get ridiculed and lose your job, I wouldn't care about that damned building, your family and yourself is important and the rest can sink into deep ***. That's how life is.
QUOTE (RealityCheck+Jun 25 2007, 02:31 AM)
Hi loz124!
Not 'some', but 'critical' lateral support, hehehe.
Just ask a Scottish Caber(pole) Tosser why he has to keep moving the fulcrum point (himself!) in order to keep a simple POLE upright.
And anyway, with all that oscillation/vibration/asymmetry induced on the 'FREE ENDS' of the lower section columns when the top 'tie in' system (hat truss) effectively separated at initial collapse, the whole shebang was 'ringing' and 'wobbling' like a bell (not to mentioned that humongous crash/sway when the jets hit and the fuel exploded).
No 'free' steel ends so high and heavy and slender will hold position under even a fraction of these circumstances....and will eventually fall from their own self-leverage due to their own unrestrained WEIGHT and instability.
Add to that the 'pressure waves' of internal debris falls and expelled air, and you will quickly see that they could NOT stand.
Besides, the very CONSTRUCTION PROCESS showed the NECESSITY EVEN AT LOWER LEVELS of the floors as support structures, or else they would have been able to raise the PERIMETER walls all the way up MUCH QUICKER than they did because they had to construct the 'floor support' to KEEP PACE with those perimeter structures.
Cheers!
RC.
.
RC,
I think it is best not to throw too many variables in there at once. The question was referring to a WTC tower prior to any plane impact - imagine a WTC tower prior to 9/11, on a day with low winds say, now we magically remove all the floors (without causing any damage).
What happens? Do the perimeter columns fall in on themselves? Does the whole tower topple over?
If you like, you can also answer this question - consider the same tower as above (floors removed, no damage). Now remove the hat truss and the core. Same questions, what happens to the perimeter structure?
QUOTE (RealityCheck+)
Hi loz124!
Not 'some', but 'critical' lateral support, hehehe.
Just ask a Scottish Caber(pole) Tosser why he has to keep moving the fulcrum point (himself!) in order to keep a simple POLE upright.
And anyway, with all that oscillation/vibration/asymmetry induced on the 'FREE ENDS' of the lower section columns when the top 'tie in' system (hat truss) effectively separated at initial collapse, the whole shebang was 'ringing' and 'wobbling' like a bell (not to mentioned that humongous crash/sway when the jets hit and the fuel exploded).
No 'free' steel ends so high and heavy and slender will hold position under even a fraction of these circumstances....and will eventually fall from their own self-leverage due to their own unrestrained WEIGHT and instability.
Add to that the 'pressure waves' of internal debris falls and expelled air, and you will quickly see that they could NOT stand.
Besides, the very CONSTRUCTION PROCESS showed the NECESSITY EVEN AT LOWER LEVELS of the floors as support structures, or else they would have been able to raise the PERIMETER walls all the way up MUCH QUICKER than they did because they had to construct the 'floor support' to KEEP PACE with those perimeter structures.
Cheers!
RC.
.
Your caber tosser example applies more to the tower as a whole, not to individual perimeter columns. The columns are connected together with the spandrel plates in threes, and these sections are bolted (adjacent sections) and welded (above and below) to each other. You end up with one large "caber". I can see the shear stress on these connections coming under increased strain under lateral wind loads without the floors - but large enough to fall apart?
Vis a vis your construction process remark - from a purely logistical standpoint, it wouldn't make much sense to raise the perimeter walls up faster than the floors. This would have required the cranes for example to keep pace with the perimeter columns, and all raised material to travel much further (over the raised perimeter structure and down to the floor). Also much more difficult to assemble the pre-fabricated perimeter structures and bolt them together. So I don't think any conclusions can be drawn from this.
QUOTE (einsteen+Jun 25 2007, 10:11 AM)
If I was a cd expert in the US I also would say "no" even if you are 99% convinced that it is a CD. You don't know what happened there, you was not there, you didn't do it, you don't care, it is not your business. I would never say yes, the social pressure is extreme, there is a risk to get ridiculed and lose your job, I wouldn't care about that damned building, your family and yourself is important and the rest can sink into deep ***. That's how life is.
But if you were a TROOFER, then OF COURSE, you are NO MERE NORMAL HUMAN.
So of course
You WOULD CARE
You WOULD ignore the Social Pressure.
You WOULDN'T care about being ridiculed.
You WOULDN'T care about losing your job (you'd file a million dollar law suit like Ryan )
etc etc ad nauseum
Right
Why is it that TROOFERs think they are the ONLY people with a moral compass?
Sheesh.
Arthur
But if you were a TROOFER, then OF COURSE, you are NO MERE NORMAL HUMAN.
So of course
You WOULD CARE
You WOULD ignore the Social Pressure.
You WOULDN'T care about being ridiculed.
You WOULDN'T care about losing your job (you'd file a million dollar law suit like Ryan
)etc etc ad nauseum
Right
Why is it that TROOFERs think they are the ONLY people with a moral compass?
Sheesh.
Arthur
einsteen
Absolute Horse POO!!! You are saying that not a single one of the THOUSANDS of Engineers, experienced CD workers, Firemen, Police and Rescue workers has any integrity whatsoever, or worse, were complicit in the murder of their fellow citizens, officers and firefighters. That is totally CRAP!!!
The FACT is that not one of these people found ANY evidence of the use of explosives. That is why they KNOW it was not a CD, whereas Jowenko based his OPINION on what a carefully edited video LOOKED LIKE and DID NOT KNOW any other of the facts surrounding 7(he is a fool to state he is certain it was CD, the most he could say was that it LOOKED LIKE a CD). Those engineers who DO know the facts surrounding 7 do not think CD is a viable option due to a total lack of evidence for the use of explosives(Thermite is never used in CDs, it is useless for cutting sideways into beams).
And, given the extreme damage visible in the link I provided, the massive fires and the extended time the fires burned unchecked, there was no need of explosives/thermite/nukes or ray beams to explain the collapse of that building.
Occam's Razor says the simplest explanation which explains all the facts is the right explanation.
Grumpy
QUOTE
Grumpy, I didn't know that. In on it ? If someone needs to say something about wtc7, what would you do ? If I was a cd expert in the US I also would say "no" even if you are 99% convinced that it is a CD. You don't know what happened there, you was not there, you didn't do it, you don't care, it is not your business. I would never say yes, the social pressure is extreme, there is a risk to get ridiculed and lose your job, I wouldn't care about that damned building, your family and yourself is important and the rest can sink into deep ***. That's how life is.
Absolute Horse POO!!! You are saying that not a single one of the THOUSANDS of Engineers, experienced CD workers, Firemen, Police and Rescue workers has any integrity whatsoever, or worse, were complicit in the murder of their fellow citizens, officers and firefighters. That is totally CRAP!!!
The FACT is that not one of these people found ANY evidence of the use of explosives. That is why they KNOW it was not a CD, whereas Jowenko based his OPINION on what a carefully edited video LOOKED LIKE and DID NOT KNOW any other of the facts surrounding 7(he is a fool to state he is certain it was CD, the most he could say was that it LOOKED LIKE a CD). Those engineers who DO know the facts surrounding 7 do not think CD is a viable option due to a total lack of evidence for the use of explosives(Thermite is never used in CDs, it is useless for cutting sideways into beams).
And, given the extreme damage visible in the link I provided, the massive fires and the extended time the fires burned unchecked, there was no need of explosives/thermite/nukes or ray beams to explain the collapse of that building.
Occam's Razor says the simplest explanation which explains all the facts is the right explanation.
Grumpy
QUOTE (Grumpy+Jun 25 2007, 10:40 AM)
...whereas Jowenko based his OPINION on what a carefully edited video LOOKED LIKE and DID NOT KNOW any other of the facts surrounding 7(he is a fool to state he is certain it was CD, the most he could say was that it LOOKED LIKE a CD).
Yeah Grumpy. In fact, they showed him the edited video without telling him it was WTC 7 until AFTERWARDS. IOWs, he didn't even know what he was looking at, yet came up with his conclusion that it was CD. He was surprised when they told him, and didn't he change his mind later after learning of other conditions?
lozenge124
First, the spandrel plates were the ONLY parts that were welded, the sections were BOLTED top, bottoms and sides. This was possible due to the forces being largely in a vertical direction and THE SUPPORT PROVIDED BY THE FLOORS against lateral forces. Without that lateral support the outer frame would have swayed uncontrollably until it snapped.
The core was even more dependent on the floors, due to it's extreme slenderness ratio and lack of cross bracing.
Neither would be able to stand once the floors were removed, the top blocks falling on top of them(after pancaking) didn't help.
Grumpy
QUOTE
Your caber tosser example applies more to the tower as a whole, not to individual perimeter columns. The columns are connected together with the spandrel plates in threes, and these sections are bolted (adjacent sections) and welded (above and below) to each other. You end up with one large "caber". I can see the shear stress on these connections coming under increased strain under lateral wind loads without the floors - but large enough to fall apart?
First, the spandrel plates were the ONLY parts that were welded, the sections were BOLTED top, bottoms and sides. This was possible due to the forces being largely in a vertical direction and THE SUPPORT PROVIDED BY THE FLOORS against lateral forces. Without that lateral support the outer frame would have swayed uncontrollably until it snapped.
The core was even more dependent on the floors, due to it's extreme slenderness ratio and lack of cross bracing.
Neither would be able to stand once the floors were removed, the top blocks falling on top of them(after pancaking) didn't help.
Grumpy
Alan (ex elevator man)
That was my understanding, but others claim he still says it was CD. If that is true he is even more a fool.
Grumpy
QUOTE
He was surprised when they told him, and didn't he change his mind later after learning of other conditions?
That was my understanding, but others claim he still says it was CD. If that is true he is even more a fool.
Grumpy
Demo Expert in Europe, Danny Jowenko, confirms WTC-7 Was Controlled Demolition
Fire ?? Eh... NO WAY!!!
www.youtube.com/watch?v=ExUTAbUCYL0
Fire ?? Eh... NO WAY!!!
www.youtube.com/watch?v=ExUTAbUCYL0
Daru
He is not only a fool, he is an idiot.
Grumpy
He is not only a fool, he is an idiot.
Grumpy
I wonder if they showed him the whole video, from the moment the east penthouse roofline kinked to the end of the collapse. Who want's to bet they just showed him the viseo of the last couple of seconds?
QUOTE (einsteen+Jun 25 2007, 02:52 AM)
First you see the roof is horizontal, then it caves in a little bit, you see all floors cave in,
Well you just answered my question in the last post. Not only didn’t they show Jowenko the whole video, but you seem to be unfamiliar with it as well.
Don’t you think that is somewhat dishonest?
Well you just answered my question in the last post. Not only didn’t they show Jowenko the whole video, but you seem to be unfamiliar with it as well.
Don’t you think that is somewhat dishonest?
Minor correction to a post yesterday: The reflection coefficient for the steel-concrete interface is R = -0.662. That is, compression waves are reflected as rarefaction waves and vice versa...
QUOTE (Palpatane+Jun 25 2007, 07:47 PM)
Well you just answered my question in the last post. Not only didn’t they show Jowenko the whole video, but you seem to be unfamiliar with it as well.
Don’t you think that is somewhat dishonest?
Are you nuts, Jowenko had seen several videos, the construction of the building etc. I've spent a week to translate the complete interview in English and put it on youtube. What was your question ?
When I saw this it gave me the shivers
http://www.youtube.com/watch?v=z9CXQY-bZn4
And then the JREF clowns, it is not literally and then we have a genuine
CNN cast.
http://www.youtube.com/watch?v=z9CXQY-bZn4
And then the JREF clowns, it is not literally and then we have a genuine
CNN cast.
einsteen
What in that video gives you the idea it did not fall from the damage and fire???
Grumpy
What in that video gives you the idea it did not fall from the damage and fire???
Grumpy
QUOTE (David B. Benson+Jun 23 2007, 11:47 PM)
A paper on the web by Daniel A. Vellone & Charles Merguerian seems to indicate the UCS (unconfined compressive strength) of the underlying Manhattan schist bedrock was 70--90 MPa. (Maybe they meant GPa?) Thus the necessity of spreading the core column load over a wider footing, I think.
However, the paper by Song/Suh/Woo/Hao in Engineering Geology 72:3--4, April 2004, 293--308, indicates that the elasticity, under confinement, increases with the confining pressure, but anyway, seems to be about 80 GPa.
From Wikipedia, high-strength concrete has a Young's modulus of about 30 GPa, while for steel it is about 200 Gpa.
I'll say there is a serious impedance mismatch.
How serious is "serious"?
In 1 second, at a speed of 5100 m/s (speed of sound in steel), this should allow approx. 15 impacts, 8 on the bottom of the columns, 7 at the top of the column/rubble zone boundary. If you figure half of the loss goes out of the bottom, and half goes out of the topy, what is the loss through the bottom
after 1 second?
However, the paper by Song/Suh/Woo/Hao in Engineering Geology 72:3--4, April 2004, 293--308, indicates that the elasticity, under confinement, increases with the confining pressure, but anyway, seems to be about 80 GPa.
From Wikipedia, high-strength concrete has a Young's modulus of about 30 GPa, while for steel it is about 200 Gpa.
I'll say there is a serious impedance mismatch.
How serious is "serious"?
In 1 second, at a speed of 5100 m/s (speed of sound in steel), this should allow approx. 15 impacts, 8 on the bottom of the columns, 7 at the top of the column/rubble zone boundary. If you figure half of the loss goes out of the bottom, and half goes out of the topy, what is the loss through the bottom
after 1 second?
QUOTE (metamars+Jun 25 2007, 08:57 PM)
How serious is "serious"?
I worked it out in a later post than the one you quote: The reflection coefficient is about -2/3, so only 1/3 of each pulse goes into the underlying concrete.
I worked it out in a later post than the one you quote: The reflection coefficient is about -2/3, so only 1/3 of each pulse goes into the underlying concrete.
QUOTE (einsteen+Jun 25 2007, 08:49 PM)
When I saw this it gave me the shivers
http://www.youtube.com/watch?v=z9CXQY-bZn4
And then the JREF clowns, it is not literally and then we have a genuine
CNN cast.
Everyone knew that building was coming down.
http://www.youtube.com/watch?v=3HLDgjYuRHk
http://www.youtube.com/watch?v=N1LetB0z8_o
http://msnbc.com/m/mp/dwvideo.asp?v=n_banf...sevenwtc_010911
It's very simple. The firefighters knew the building was coming down at some point because of the damage to the building, the unfought fires and monitoring the buildings performance (Transit). They told everyone to get back and wait for the collapse. It would be obvious to a child that the media would want to know why they couldn't go down to ground zero. They must have been told the reason was the WTC 7 was going to collapse. SIMPLE.
The downright absurd conspiracy story: The government told many reporters to report something they would have reported anyway after the building collapsed.
http://www.youtube.com/watch?v=z9CXQY-bZn4
And then the JREF clowns, it is not literally and then we have a genuine
CNN cast.
Everyone knew that building was coming down.
http://www.youtube.com/watch?v=3HLDgjYuRHk
http://www.youtube.com/watch?v=N1LetB0z8_o
http://msnbc.com/m/mp/dwvideo.asp?v=n_banf...sevenwtc_010911
It's very simple. The firefighters knew the building was coming down at some point because of the damage to the building, the unfought fires and monitoring the buildings performance (Transit). They told everyone to get back and wait for the collapse. It would be obvious to a child that the media would want to know why they couldn't go down to ground zero. They must have been told the reason was the WTC 7 was going to collapse. SIMPLE.
The downright absurd conspiracy story: The government told many reporters to report something they would have reported anyway after the building collapsed.
QUOTE (einsteen+Jun 25 2007, 08:52 AM)
If you look at the collapse of wtc7 and then especially the Naudet video, then if it is caused by a failue of one story you also see the effect that a complete shockwave goes throught the whole building. First you see the roof is horizontal, then it caves in a little bit, you see all floors cave in, I would say that at that moment the buiding then is broken on several levels. In the long Jowenko video he explains that there is also a technique in which you don't need charges on higher levels, you only have to cut (with a torch) the columns in a V shape, they are then still on top of each other, but if there is initiation you get more fall speed because they are already broken on the higher levels. But as I said I'm not sure about that total crush up, if you have a piece of material, very general, and drop it on a solid ground then why would the energy concentrate on the lower part?
Hi ein!
It would seem by your comments that you are not aware of the DIFFERENCE in construction/structure of WTC7.
It had a CANTILEVER system at its lower levels which, when it finally failed (due to diesel/furniture fire weakening, cooling stress over the 7hrs it burned UNFOUGHT etc), the whiole structure was left without legs at various points during the final failure/collapse....that is not even considering the internal PARTIAL collapses that obviously occurred 'piecemeal' as the event progressed from the wiidespread fires started by widespread 'burning-hot' debris from the taller tower collapses and the diesel fuel still being pumped by the internal fuel distribution system until the lower levels were finally caput.
WTC7 was a messier and way more prolonged collapse overall than was either of the tall towers.
But even there, we have similarities if we look for them.
Mainly that the 'processes' leading to the initial collapses of the upper WTC1&2 'box' sections were similar to the eventual 'main all at one' TERMINAL PHASE collapse of WTC7....
.....simply because, just as in WTC7 collapse, in WTC1&2 the 'legs' were finally GONE from under the 'upper box' (equivalent to a MULTI-STOREY BUILDING in its own right!...and HEAVIER than an equivalent building due to HAT TRUSS STRUCTURE as well!)....with the inevitable AND SIMILAR results we saw in all three cases.
So you can see that from some 'sides', the WTC7 collapse, because of its lower levels cantilever failure, resembled the tall tower TOP SECTION collapses due to THEIR 'impact/fire levels' collapsing LOCALLY and then progressing through the lower tower section....which WTC7 ALSO DID in PROGRESSING past the cantilever floors to ITS 'basement'.
So in effect, IF WTC7 had been a much taller building (say another twenty stories), and thus would have had many MORE LOWER FLOORS below the cantilever structure than just those basement levels, IT TOO would have LOOKED JUST LIKE WTC1&2....ie, yet ANOTHER LOCAL COLLAPSE scenario 'at the cantilever/impact/fire levels' which would proceed to ITS lower 'multi-floor lower section'....as MORE VISIBLE in the tall tower cases!
In effect, the processes at WTC7 provide FURTHER CONFIRMATION of the observed BEHAVIOUR of such 'piecemeal steel' and 'large unsupported intervening floor space' and 'vulnerable floor-to-wall' buildings IN THE EVENT OF MAJOR IMPACT AND FIRE DAMAGE IN UNCONTROLLED situations where FUEL LOAD (diesel, Jetfuel, furniture/fittings etc) was AMPLE to produce what was observed.
See?
Cheers all!
RC.
.
Hi ein!
It would seem by your comments that you are not aware of the DIFFERENCE in construction/structure of WTC7.
It had a CANTILEVER system at its lower levels which, when it finally failed (due to diesel/furniture fire weakening, cooling stress over the 7hrs it burned UNFOUGHT etc), the whiole structure was left without legs at various points during the final failure/collapse....that is not even considering the internal PARTIAL collapses that obviously occurred 'piecemeal' as the event progressed from the wiidespread fires started by widespread 'burning-hot' debris from the taller tower collapses and the diesel fuel still being pumped by the internal fuel distribution system until the lower levels were finally caput.
WTC7 was a messier and way more prolonged collapse overall than was either of the tall towers.
But even there, we have similarities if we look for them.
Mainly that the 'processes' leading to the initial collapses of the upper WTC1&2 'box' sections were similar to the eventual 'main all at one' TERMINAL PHASE collapse of WTC7....
.....simply because, just as in WTC7 collapse, in WTC1&2 the 'legs' were finally GONE from under the 'upper box' (equivalent to a MULTI-STOREY BUILDING in its own right!...and HEAVIER than an equivalent building due to HAT TRUSS STRUCTURE as well!)....with the inevitable AND SIMILAR results we saw in all three cases.
So you can see that from some 'sides', the WTC7 collapse, because of its lower levels cantilever failure, resembled the tall tower TOP SECTION collapses due to THEIR 'impact/fire levels' collapsing LOCALLY and then progressing through the lower tower section....which WTC7 ALSO DID in PROGRESSING past the cantilever floors to ITS 'basement'.
So in effect, IF WTC7 had been a much taller building (say another twenty stories), and thus would have had many MORE LOWER FLOORS below the cantilever structure than just those basement levels, IT TOO would have LOOKED JUST LIKE WTC1&2....ie, yet ANOTHER LOCAL COLLAPSE scenario 'at the cantilever/impact/fire levels' which would proceed to ITS lower 'multi-floor lower section'....as MORE VISIBLE in the tall tower cases!
In effect, the processes at WTC7 provide FURTHER CONFIRMATION of the observed BEHAVIOUR of such 'piecemeal steel' and 'large unsupported intervening floor space' and 'vulnerable floor-to-wall' buildings IN THE EVENT OF MAJOR IMPACT AND FIRE DAMAGE IN UNCONTROLLED situations where FUEL LOAD (diesel, Jetfuel, furniture/fittings etc) was AMPLE to produce what was observed.
See?
Cheers all!
RC.
.
QUOTE (lozenge124+Jun 25 2007, 03:25 PM)
RC,
I think it is best not to throw too many variables in there at once. The question was referring to a WTC tower prior to any plane impact - imagine a WTC tower prior to 9/11, on a day with low winds say, now we magically remove all the floors (without causing any damage).
What happens? Do the perimeter columns fall in on themselves? Does the whole tower topple over?
If you like, you can also answer this question - consider the same tower as above (floors removed, no damage). Now remove the hat truss and the core. Same questions, what happens to the perimeter structure?
.....
Your caber tosser example applies more to the tower as a whole, not to individual perimeter columns. The columns are connected together with the spandrel plates in threes, and these sections are bolted (adjacent sections) and welded (above and below) to each other. You end up with one large "caber". I can see the shear stress on these connections coming under increased strain under lateral wind loads without the floors - but large enough to fall apart?
Vis a vis your construction process remark - from a purely logistical standpoint, it wouldn't make much sense to raise the perimeter walls up faster than the floors. This would have required the cranes for example to keep pace with the perimeter columns, and all raised material to travel much further (over the raised perimeter structure and down to the floor). Also much more difficult to assemble the pre-fabricated perimeter structures and bolt them together. So I don't think any conclusions can be drawn from this.
Hi loz124!
Why do you unilateraly/arbitrarily 'bound' the caber tossing example to apply ONLY to the WHOLE building?
ANY sufficiently long/heavy LEVER state will produce/amplify DESTRUCTIVE forces at its 'fulcrum' COMMENSURATE with its scale.
That is the lever/wedge principle AT ALL SCALES. No?
So it's fair to say that at the scale of BOLTS/WELDS and the WOBBLING/OSCILLATING/SIDE-PRESSURED column sections would act to amplify the forces at THEIR fulcrums (at various lengths and times/durations).
And as for removing floors in the INTACT tower structures.....you should read the old threads where the troofers themselves maintained, and presented evidence in supprt, that the floors were INTEGRAL to load distribution/sharing between the perimeter walls and core structure so that NEITHER was put into EXCURSION from their designed parameters (which were exceeded anyway in the event due to impact/fire/load-redistribution/local collapse etc for which the structures were HOPELESSLY 'underdesigned'....but I suppose they could not foresee the catalogue of failures of fireproofing, loss of sprinkler/manned firefighting systems, and FLOOR TRUSS FAILURES involved in LOCAL COLLAPSE and FLOOR, BOLT-WELD vulnerabilies and FAILURES under the subsequent dynamic loads involved in GLOBAL COLLAPSE thereafter etc!).
And if we DID remove 5-10 floors worth of lateral support for the inner/outer walls, as you visualised could be done without 'harm', consider that any forces on the perimeter and 'core structures/faces would THEN eventually be CONCENTRATED at that ONE 'point' in the whole height where the forces were NOT 'equalised/damped' and so EVERYTHING would effectively have been 'fulcruming' at that 'floorless point'....with the result that not only would the TOP section begin swaying DESTRUCTIVELY as 'harmonic motion' ACCUMULATED the forces to extreme OFF-axis movement beyond the design parameters, but it would also be destroying LOCAL 'piecemeal' connections of the CORE structure beginning with the weakest and overloading the next strongest etc IN QUICK SUCCESSION.
And of course, IF the perimeter and 'core' steelwork COULD have progressed WITHOUT the floors to brace them (as you maintain), then what's to stop the builders from using THEM as the CRANE STRUCTURE/BASES as they 'construct themselves' and thus would save much time and money using/extending 'kangaroo cranes' for the job?
So I think that if they could have got away with it they would have. But anyway, even the documents/evidence/design statements MAKE QUITE EXPLICITLY CLEAR even before these events, that the whole buildinbg was INTERDEPENDENT with every OTHER part of it....which is the MINIMALIST feature of the structure that allowed them to have all that EMPTY/UNSUPPORTED FLOOR-SPACE between the inner and outer 'tubes' that were both interconnected/dependent on each other VIA THE FLOORS at all stages....with the final TOP HAT TRUSS being the most STRONG 'floors' structure/levels serving not only for load transfer between perimeter and core BUT ALSO to functioning to 'tie up the loose ends' of the upper columns to prevent 'unzipping' LEVERAGE FORCES from ever building up (due to harmonic motion behaviour).
See?
Cheers all!
RC.
.
I think it is best not to throw too many variables in there at once. The question was referring to a WTC tower prior to any plane impact - imagine a WTC tower prior to 9/11, on a day with low winds say, now we magically remove all the floors (without causing any damage).
What happens? Do the perimeter columns fall in on themselves? Does the whole tower topple over?
If you like, you can also answer this question - consider the same tower as above (floors removed, no damage). Now remove the hat truss and the core. Same questions, what happens to the perimeter structure?
.....
Your caber tosser example applies more to the tower as a whole, not to individual perimeter columns. The columns are connected together with the spandrel plates in threes, and these sections are bolted (adjacent sections) and welded (above and below) to each other. You end up with one large "caber". I can see the shear stress on these connections coming under increased strain under lateral wind loads without the floors - but large enough to fall apart?
Vis a vis your construction process remark - from a purely logistical standpoint, it wouldn't make much sense to raise the perimeter walls up faster than the floors. This would have required the cranes for example to keep pace with the perimeter columns, and all raised material to travel much further (over the raised perimeter structure and down to the floor). Also much more difficult to assemble the pre-fabricated perimeter structures and bolt them together. So I don't think any conclusions can be drawn from this.
Hi loz124!
Why do you unilateraly/arbitrarily 'bound' the caber tossing example to apply ONLY to the WHOLE building?
ANY sufficiently long/heavy LEVER state will produce/amplify DESTRUCTIVE forces at its 'fulcrum' COMMENSURATE with its scale.
That is the lever/wedge principle AT ALL SCALES. No?
So it's fair to say that at the scale of BOLTS/WELDS and the WOBBLING/OSCILLATING/SIDE-PRESSURED column sections would act to amplify the forces at THEIR fulcrums (at various lengths and times/durations).
And as for removing floors in the INTACT tower structures.....you should read the old threads where the troofers themselves maintained, and presented evidence in supprt, that the floors were INTEGRAL to load distribution/sharing between the perimeter walls and core structure so that NEITHER was put into EXCURSION from their designed parameters (which were exceeded anyway in the event due to impact/fire/load-redistribution/local collapse etc for which the structures were HOPELESSLY 'underdesigned'....but I suppose they could not foresee the catalogue of failures of fireproofing, loss of sprinkler/manned firefighting systems, and FLOOR TRUSS FAILURES involved in LOCAL COLLAPSE and FLOOR, BOLT-WELD vulnerabilies and FAILURES under the subsequent dynamic loads involved in GLOBAL COLLAPSE thereafter etc!).
And if we DID remove 5-10 floors worth of lateral support for the inner/outer walls, as you visualised could be done without 'harm', consider that any forces on the perimeter and 'core structures/faces would THEN eventually be CONCENTRATED at that ONE 'point' in the whole height where the forces were NOT 'equalised/damped' and so EVERYTHING would effectively have been 'fulcruming' at that 'floorless point'....with the result that not only would the TOP section begin swaying DESTRUCTIVELY as 'harmonic motion' ACCUMULATED the forces to extreme OFF-axis movement beyond the design parameters, but it would also be destroying LOCAL 'piecemeal' connections of the CORE structure beginning with the weakest and overloading the next strongest etc IN QUICK SUCCESSION.
And of course, IF the perimeter and 'core' steelwork COULD have progressed WITHOUT the floors to brace them (as you maintain), then what's to stop the builders from using THEM as the CRANE STRUCTURE/BASES as they 'construct themselves' and thus would save much time and money using/extending 'kangaroo cranes' for the job?
So I think that if they could have got away with it they would have. But anyway, even the documents/evidence/design statements MAKE QUITE EXPLICITLY CLEAR even before these events, that the whole buildinbg was INTERDEPENDENT with every OTHER part of it....which is the MINIMALIST feature of the structure that allowed them to have all that EMPTY/UNSUPPORTED FLOOR-SPACE between the inner and outer 'tubes' that were both interconnected/dependent on each other VIA THE FLOORS at all stages....with the final TOP HAT TRUSS being the most STRONG 'floors' structure/levels serving not only for load transfer between perimeter and core BUT ALSO to functioning to 'tie up the loose ends' of the upper columns to prevent 'unzipping' LEVERAGE FORCES from ever building up (due to harmonic motion behaviour).
See?
Cheers all!
RC.
.
QUOTE
The reflection coefficient for the steel-concrete interface is R = -0.662.
I'm just asking, I really don't know the answer myself, but isn't the *energy* coupled from one medium to the next proportional to the *square* of the coupling coefficient (=1-reflection coefficient)?
In other words, if the reflection coefficient is 0.662, then the coupling coefficient would be (1-0.662) = 0.338, and the *energy* coupled from the steel to the concrete would be 0.338^2 or .114?
I get confused because this is worked one way with light and another with microwave waveguides, but I think the reflection coefficient deals with amplitudes, and the energy is proportional to the square of the amplitude.
Correct me if I'm wrong...
The other point to remember is that this attenuation concatenates with other places where the impedance is mismatched, so it isn't just between the steel and the bathtub, but the tower and the main lobby and the main lobby and the basement... All those impedance mismatches have to be multiplied in series.
(That much I'm sure about.)
QUOTE (Grumpy+Jun 25 2007, 05:24 PM)
Daru
He is not only a fool, he is an idiot.
Grumpy
really? can you document some of his failed demos for us, then? can you show us how incompetent he is in his field with real world examples?
because, as far as i see, there is SOMEONE who looks like a fool and an idiot, and it's DEFINITELY NOT jowenko.
He is not only a fool, he is an idiot.
Grumpy
really? can you document some of his failed demos for us, then? can you show us how incompetent he is in his field with real world examples?
because, as far as i see, there is SOMEONE who looks like a fool and an idiot, and it's DEFINITELY NOT jowenko.
QUOTE (wcelliott+Jun 26 2007, 01:03 AM)
In other words, if the reflection coefficient is 0.662, then the coupling coefficient would be (1-0.662) = 0.338, and the *energy* coupled from the steel to the concrete would be 0.338^2 or .114?
... but I think the reflection coefficient deals with amplitudes, and the energy is proportional to the square of the amplitude.
The other point to remember is that this attenuation concatenates with other places where the impedance is mismatched, so it isn't just between the steel and the bathtub, but the tower and the main lobby and the main lobby and the basement... All those impedance mismatches have to be multiplied in series.
(That much I'm sure about.)
Yes, thank you for the correction!
Yes, but I'm just interested in the core columns. I'm going to assume that all 40 or so vertical connections have no impedance mismatch. This can only be an approximation, especially for the (going downward) wide flange rolled steel to box column transition and again from box columns without a plate in the center to the next down, which do. But just now I have no way to even attempt an approximation for the impedance mismatch, so I'll just arbitrarily assume there is none...
Have you a better suggestion?
... but I think the reflection coefficient deals with amplitudes, and the energy is proportional to the square of the amplitude.
The other point to remember is that this attenuation concatenates with other places where the impedance is mismatched, so it isn't just between the steel and the bathtub, but the tower and the main lobby and the main lobby and the basement... All those impedance mismatches have to be multiplied in series.
(That much I'm sure about.)
Yes, thank you for the correction!
Yes, but I'm just interested in the core columns. I'm going to assume that all 40 or so vertical connections have no impedance mismatch. This can only be an approximation, especially for the (going downward) wide flange rolled steel to box column transition and again from box columns without a plate in the center to the next down, which do. But just now I have no way to even attempt an approximation for the impedance mismatch, so I'll just arbitrarily assume there is none...
Have you a better suggestion?
QUOTE (RealityCheck+Jun 26 2007, 12:12 AM)
Hi loz124!
Why do you unilateraly/arbitrarily 'bound' the caber tossing example to apply ONLY to the WHOLE building?
ANY sufficiently long/heavy LEVER state will produce/amplify DESTRUCTIVE forces at its 'fulcrum' COMMENSURATE with its scale.
That is the lever/wedge principle AT ALL SCALES. No?
So it's fair to say that at the scale of BOLTS/WELDS and the WOBBLING/OSCILLATING/SIDE-PRESSURED column sections would act to amplify the forces at THEIR fulcrums (at various lengths and times/durations).
And as for removing floors in the INTACT tower structures.....you should read the old threads where the troofers themselves maintained, and presented evidence in supprt, that the floors were INTEGRAL to load distribution/sharing between the perimeter walls and core structure so that NEITHER was put into EXCURSION from their designed parameters (which were exceeded anyway in the event due to impact/fire/load-redistribution/local collapse etc for which the structures were HOPELESSLY 'underdesigned'....but I suppose they could not foresee the catalogue of failures of fireproofing, loss of sprinkler/manned firefighting systems, and FLOOR TRUSS FAILURES involved in LOCAL COLLAPSE and FLOOR, BOLT-WELD vulnerabilies and FAILURES under the subsequent dynamic loads involved in GLOBAL COLLAPSE thereafter etc!).
And if we DID remove 5-10 floors worth of lateral support for the inner/outer walls, as you visualised could be done without 'harm', consider that any forces on the perimeter and 'core structures/faces would THEN eventually be CONCENTRATED at that ONE 'point' in the whole height where the forces were NOT 'equalised/damped' and so EVERYTHING would effectively have been 'fulcruming' at that 'floorless point'....with the result that not only would the TOP section begin swaying DESTRUCTIVELY as 'harmonic motion' ACCUMULATED the forces to extreme OFF-axis movement beyond the design parameters, but it would also be destroying LOCAL 'piecemeal' connections of the CORE structure beginning with the weakest and overloading the next strongest etc IN QUICK SUCCESSION.
And of course, IF the perimeter and 'core' steelwork COULD have progressed WITHOUT the floors to brace them (as you maintain), then what's to stop the builders from using THEM as the CRANE STRUCTURE/BASES as they 'construct themselves' and thus would save much time and money using/extending 'kangaroo cranes' for the job?
So I think that if they could have got away with it they would have. But anyway, even the documents/evidence/design statements MAKE QUITE EXPLICITLY CLEAR even before these events, that the whole buildinbg was INTERDEPENDENT with every OTHER part of it....which is the MINIMALIST feature of the structure that allowed them to have all that EMPTY/UNSUPPORTED FLOOR-SPACE between the inner and outer 'tubes' that were both interconnected/dependent on each other VIA THE FLOORS at all stages....with the final TOP HAT TRUSS being the most STRONG 'floors' structure/levels serving not only for load transfer between perimeter and core BUT ALSO to functioning to 'tie up the loose ends' of the upper columns to prevent 'unzipping' LEVERAGE FORCES from ever building up (due to harmonic motion behaviour).
See?
Cheers all!
RC.
.
Hi RC,
I'll take that as a yes. Without the floors, you believe the perimeter columns would fall over being inherently stable.
I don't happen to agree with this. My feeling is that as the perimeter columns were designed to support both lateral and vertical loads (while the core was only designed for vertical loads), it would hold up better than that, especially in low wind situations; in a strong wind close to the max design parameters it might not fare as well, but the staggered system of bolting the perimeter sections together, and the angled corners of the towers, seems well enough thought out for the tower perimeter structure to be considered as one unit, not small individual "cabers" flapping individually.
Granted, as with your post, this is just my opinion unbacked by any hard evidence. (I do not have any statements/papers that consider this scenario).
But thanks for sharing your thoughts.
QUOTE (lozenge124+Jun 26 2007, 01:45 AM)
Hi RC,
I'll take that as a yes. Without the floors, you believe the perimeter columns would fall over being inherently stable.
I don't happen to agree with this. My feeling is that as the perimeter columns were designed to support both lateral and vertical loads (while the core was only designed for vertical loads), it would hold up better than that, especially in low wind situations; in a strong wind close to the max design parameters it might not fare as well, but the staggered system of bolting the perimeter sections together, and the angled corners of the towers, seems well enough thought out for the tower perimeter structure to be considered as one unit, not small individual "cabers" flapping individually.
Granted, as with your post, this is just my opinion unbacked by any hard evidence. (I do not have any statements/papers that consider this scenario).
But thanks for sharing your thoughts.
Hi loz124.
I think you meant to type "inherently UNstable"?
Actually, I referred you to the actual designers/builder's comments/design documents and specifications/principles as already (in the old threads) presented in evidence in the discussion by troofers themselves.
So I have no 'opinion' except that based on the extrapolation from a 'unified' analysis in principle of BOTH the design parameters/limits and readily-confirmable (by everyone including yourself in the scientific literature) physical/chemical/thermodynamic behaviour/priciples applied to the materials/processes ostensibly present in 9/11....which so far do not require 'manmade CD explosives' to give what was observed.
But as you have said, yours IS an 'opinion' ONLY until you DO present some objective evidence/argument based in the science and NOT in the 'gut feeling' or 'political' "reasoning".
And the 'cabers' analogy was to demonstrate the virtual impossibility without perfectly functioning ACTIVE CONTROL systems to control/stop an IMBALANCE 'tipping' of a long upright lever (in WTC case especially under severe oscillation and vibration and CONNECTION-WEAKENING/BREAKING 'pre-damage from impact/fire/collapse asymmetries and load-shifting etc which effectively exposed INDIVIDULA column SECTIONS/HEIGHTS to various overwhelming forces which made them act as levers WITHIN A SMALL TIME/DISTANCE but nevertheless for FAR/LONG enough to severely compromise the BOLTS/WELDS before total destruction attendant to this 'weakening/compromising' of the TOTAL INTEGRITY of a structure that was INORDINATELY DEPENDENT on the whole to 'work' for its survival under any conditions which put any member out of design parameters to the extent that they were in 9/11 (or would have even as built if 5-10 level section of floor lateral supprt was removed in 'normal use' conditions).
I think you will have to read the older threads in order to answer most of your questions....as a lot of what is in THIS thread is mere repetition of the same arguments, only THIS TIME ROUND with less reference to the 'evidence' base appearing in the old threads! hehehe.
Good luck!
Cheeers all!
RC.
.
I'll take that as a yes. Without the floors, you believe the perimeter columns would fall over being inherently stable.
I don't happen to agree with this. My feeling is that as the perimeter columns were designed to support both lateral and vertical loads (while the core was only designed for vertical loads), it would hold up better than that, especially in low wind situations; in a strong wind close to the max design parameters it might not fare as well, but the staggered system of bolting the perimeter sections together, and the angled corners of the towers, seems well enough thought out for the tower perimeter structure to be considered as one unit, not small individual "cabers" flapping individually.
Granted, as with your post, this is just my opinion unbacked by any hard evidence. (I do not have any statements/papers that consider this scenario).
But thanks for sharing your thoughts.
Hi loz124.
I think you meant to type "inherently UNstable"?
Actually, I referred you to the actual designers/builder's comments/design documents and specifications/principles as already (in the old threads) presented in evidence in the discussion by troofers themselves.
So I have no 'opinion' except that based on the extrapolation from a 'unified' analysis in principle of BOTH the design parameters/limits and readily-confirmable (by everyone including yourself in the scientific literature) physical/chemical/thermodynamic behaviour/priciples applied to the materials/processes ostensibly present in 9/11....which so far do not require 'manmade CD explosives' to give what was observed.
But as you have said, yours IS an 'opinion' ONLY until you DO present some objective evidence/argument based in the science and NOT in the 'gut feeling' or 'political' "reasoning".
And the 'cabers' analogy was to demonstrate the virtual impossibility without perfectly functioning ACTIVE CONTROL systems to control/stop an IMBALANCE 'tipping' of a long upright lever (in WTC case especially under severe oscillation and vibration and CONNECTION-WEAKENING/BREAKING 'pre-damage from impact/fire/collapse asymmetries and load-shifting etc which effectively exposed INDIVIDULA column SECTIONS/HEIGHTS to various overwhelming forces which made them act as levers WITHIN A SMALL TIME/DISTANCE but nevertheless for FAR/LONG enough to severely compromise the BOLTS/WELDS before total destruction attendant to this 'weakening/compromising' of the TOTAL INTEGRITY of a structure that was INORDINATELY DEPENDENT on the whole to 'work' for its survival under any conditions which put any member out of design parameters to the extent that they were in 9/11 (or would have even as built if 5-10 level section of floor lateral supprt was removed in 'normal use' conditions).
I think you will have to read the older threads in order to answer most of your questions....as a lot of what is in THIS thread is mere repetition of the same arguments, only THIS TIME ROUND with less reference to the 'evidence' base appearing in the old threads! hehehe.
Good luck!
Cheeers all!
RC.
.
newton
He is a fool because he formed an opinion based only on a video he saw(I saw the original video of him watching 7 for the first time). He would have been just as much of a fool if his conclusion had been no CD. He simply did not have enough info to form a valid opinion of any sort.
He is an idiot because he has had enough time to learn more but evidently hasn't. Those who know the facts dismiss CD due to a complete lack of evidence for the use of explosives. He is of course not the only person that qualifies, but it is those who know the least who are so sure that 7 was a CD(in fact the less you know, the more sure you are that it was a CD), those who know more see that there is a simpler, more logical explanation requiring only the forces of the damage and fires.
Grumpy
PS When speaking of knowing, I am talking about valid evidence, not CTer myths and disinformation, of which there are huge steaming piles all over the kookosphere.
QUOTE
really? can you document some of his failed demos for us, then? can you show us how incompetent he is in his field with real world examples?
because, as far as i see, there is SOMEONE who looks like a fool and an idiot, and it's DEFINITELY NOT jowenko.
because, as far as i see, there is SOMEONE who looks like a fool and an idiot, and it's DEFINITELY NOT jowenko.
He is a fool because he formed an opinion based only on a video he saw(I saw the original video of him watching 7 for the first time). He would have been just as much of a fool if his conclusion had been no CD. He simply did not have enough info to form a valid opinion of any sort.
He is an idiot because he has had enough time to learn more but evidently hasn't. Those who know the facts dismiss CD due to a complete lack of evidence for the use of explosives. He is of course not the only person that qualifies, but it is those who know the least who are so sure that 7 was a CD(in fact the less you know, the more sure you are that it was a CD), those who know more see that there is a simpler, more logical explanation requiring only the forces of the damage and fires.
Grumpy
PS When speaking of knowing, I am talking about valid evidence, not CTer myths and disinformation, of which there are huge steaming piles all over the kookosphere.
QUOTE (einsteen+Jun 25 2007, 03:43 PM)
Are you nuts, Jowenko had seen several videos, the construction of the building etc. I've spent a week to translate the complete interview in English and put it on youtube. What was your question ?
Have you got someone we can trust to INDEPENDENTLY confirm your translation?
On the other hand we have this:
http://www.youtube.com/watch?v=EkZMQAC95kI
As Jowenko discusses WTC 1 and 2.
Wonder why Troofers don't push THIS interview.
Arthur
Have you got someone we can trust to INDEPENDENTLY confirm your translation?
On the other hand we have this:
http://www.youtube.com/watch?v=EkZMQAC95kI
As Jowenko discusses WTC 1 and 2.
Wonder why Troofers don't push THIS interview.
Arthur
The forces of fire...
Arthur, as I said before Danny Jowenko is the best friend of the OCT.
And my translation is literally what he said in Dutch, sometimes even too literally
someone told me. I hope you don't think I'm faking things.
And my translation is literally what he said in Dutch, sometimes even too literally
someone told me. I hope you don't think I'm faking things.
einsteen
Actually, like the Dutch student originally "taken in" by the loose change video, the more valid evidence you study, the less sense the propoganda in that video holds up to scrutiny. By the time you have researched the real story "Loose Change" is seen for the hatchet job on the truth that it actually is.
Bottom line, there was no deliberate destruction on any of those buildings(other than that perpetrated by the hijackers), there was no massive conspiracy or coverup, noone was "in on it", there was no "it" to be in on and all the destruction of 911 was caused by those aircraft impacts and the fires they started.
Grumpy
Actually, like the Dutch student originally "taken in" by the loose change video, the more valid evidence you study, the less sense the propoganda in that video holds up to scrutiny. By the time you have researched the real story "Loose Change" is seen for the hatchet job on the truth that it actually is.
Bottom line, there was no deliberate destruction on any of those buildings(other than that perpetrated by the hijackers), there was no massive conspiracy or coverup, noone was "in on it", there was no "it" to be in on and all the destruction of 911 was caused by those aircraft impacts and the fires they started.
Grumpy
QUOTE
Those who know the facts dismiss CD due to a complete lack of evidence for the use of explosives.
I'd like to add to Grumpy's statement. It isn't merely a LACK of evidence that explosives were used, it's the PRESENCE' of evidence that EXPLOSIVES WEREN'T USED.
The collapse happened in slow motion, starting with the bowing inward of the perimeter columns. That happened VERY SLOWLY, over the course of at least 20 MINUTES. No explosive works slowly. Not even thermite.
I'm late for work, so this will be a short subset of the actual list.
The other point to consider is that if it'd been planned, they'd have had to have planned it extraordinarily carefully, as much of the phenomena that we saw was to be expected, but only if you really understand how things work. If they'd have faked it, it would've ended up looking like something out of The Matrix.
The very things that made the troothers originally object to it as looking fishy have all been proved to be exactly what physics required. If the government had been involved in faking it, some committee would've made a wrong decision someplace and it would've ended up looking like what that committee thought it *ought* to look like, and it would've been wrong.
We've got over three hundred pages of examples of stuff that people *thought* looked wrong and none of those things panned out. The troothers still have no Smoking Gun. How many of those things would've ended up getting past a planning committee?
QUOTE (einsteen+Jun 26 2007, 08:38 AM)
Arthur, as I said before Danny Jowenko is the best friend of the OCT.
And my translation is literally what he said in Dutch, sometimes even too literally
someone told me. I hope you don't think I'm faking things.
I assume you aren't faking, but the act of translation often involves making judgements.
Yours are a tad questionable.
For instance:
Just saw a post about a Steven E Jones paper at JREF.
http://journalof911studies.com/volume/2007...11SciMethod.pdf
He refers to the recently discussed Kuttler paper, ignore that, but his wtc7 part is excellent.
As scientists we have to include that evidence and not just limit ourselves to floor 8 to 46 as NIST solicitation requires.
I always thought it couldn't be more crazy than it already was, my jaws dropped on my desk...
Arthur
I'd like to add to Grumpy's statement. It isn't merely a LACK of evidence that explosives were used, it's the PRESENCE' of evidence that EXPLOSIVES WEREN'T USED.
The collapse happened in slow motion, starting with the bowing inward of the perimeter columns. That happened VERY SLOWLY, over the course of at least 20 MINUTES. No explosive works slowly. Not even thermite.
Straw man. If the core columns are being systematically and slowly being taken out, why should load not be transferred to the perimeter, just as slowly?
I'm late for work, so this will be a short subset of the actual list.
The other point to consider is that if it'd been planned, they'd have had to have planned it extraordinarily carefully, as much of the phenomena that we saw was to be expected, but only if you really understand how things work. If they'd have faked it, it would've ended up looking like something out of The Matrix.
Straw man. The reason that WTC 7 videos were kept off television, but not WTC 1 & 2, probably has to do with the fact that WTC 1 and 2 are more in accord with what a gravity driven collapse would look like. If they had made 1 and 2 look like 7, and shown that on TV, the jig would have been up from Day 1.
I hope you keep your day job, and don't switch to something like detective work.
Straw man. The reason that WTC 7 videos were kept off television, but not WTC 1 & 2, probably has to do with the fact that WTC 1 and 2 are more in accord with what a gravity driven collapse would look like. If they had made 1 and 2 look like 7, and shown that on TV, the jig would have been up from Day 1.
I hope you keep your day job, and don't switch to something like detective work.
The very things that made the troothers originally object to it as looking fishy have all been proved to be exactly what physics required.
Bald assertion. You make a good OCT'er, but your critical thinking skills are another matter.
If the government had been involved in faking it, some committee would've made a wrong decision someplace and it would've ended up looking like what that committee thought it *ought* to look like, and it would've been wrong.
Staw man. Isn't it convenient that government incompetence is trotted out as an explanation when that is expedient, but government competence is trotted out (e.g., in the confidence expressed in NIST's detail-free "no evidence of CD" malarkey) when that is expedient?
Staw man. Isn't it convenient that government incompetence is trotted out as an explanation when that is expedient, but government competence is trotted out (e.g., in the confidence expressed in NIST's detail-free "no evidence of CD" malarkey) when that is expedient?
We've got over three hundred pages of examples of stuff that people *thought* looked wrong and none of those things panned out.
No, but please keep saying this. It shows how much we can trust you.
The troothers still have no Smoking Gun. How many of those things would've ended up getting past a planning committee?
While the final disposition of the thermate evidence lies with the scientific community, Professor Jones has described it as exactly that - i.e., a "smoking gun". The videographic evidence of CD is compelling, though unfortunately no comprehensive paper dealing with both concrete comminution and fluid dynamics of air/concrete/other particulate flows has been produced.
Then again, there's not been a compelling analysis of the collapse, proper, which, if were such to be done and showed that global collapse is either impossible or else would have taken much longer than observed, calculating fluid flows, etc., would be superfluous.
In short, you are a hand-waving propagandist. Correct me if I'm wrong, but have you even posted one back-of-the-envelope calculation on this thread? (Never mind anything like a careful analysis.)
I don't think so....
And my translation is literally what he said in Dutch, sometimes even too literally
someone told me. I hope you don't think I'm faking things.
I assume you aren't faking, but the act of translation often involves making judgements.
Yours are a tad questionable.
For instance:
QUOTE (einsteen+)
Just saw a post about a Steven E Jones paper at JREF.
http://journalof911studies.com/volume/2007...11SciMethod.pdf
He refers to the recently discussed Kuttler paper, ignore that, but his wtc7 part is excellent.
As scientists we have to include that evidence and not just limit ourselves to floor 8 to 46 as NIST solicitation requires.
I always thought it couldn't be more crazy than it already was, my jaws dropped on my desk...
Arthur
QUOTE (wcelliott+Jun 26 2007, 02:11 PM)
I'd like to add to Grumpy's statement. It isn't merely a LACK of evidence that explosives were used, it's the PRESENCE' of evidence that EXPLOSIVES WEREN'T USED.
The collapse happened in slow motion, starting with the bowing inward of the perimeter columns. That happened VERY SLOWLY, over the course of at least 20 MINUTES. No explosive works slowly. Not even thermite.
Straw man. If the core columns are being systematically and slowly being taken out, why should load not be transferred to the perimeter, just as slowly?
QUOTE
I'm late for work, so this will be a short subset of the actual list.
The other point to consider is that if it'd been planned, they'd have had to have planned it extraordinarily carefully, as much of the phenomena that we saw was to be expected, but only if you really understand how things work. If they'd have faked it, it would've ended up looking like something out of The Matrix.
Straw man. The reason that WTC 7 videos were kept off television, but not WTC 1 & 2, probably has to do with the fact that WTC 1 and 2 are more in accord with what a gravity driven collapse would look like. If they had made 1 and 2 look like 7, and shown that on TV, the jig would have been up from Day 1.
I hope you keep your day job, and don't switch to something like detective work.
QUOTE (->
| QUOTE |
I'm late for work, so this will be a short subset of the actual list. The other point to consider is that if it'd been planned, they'd have had to have planned it extraordinarily carefully, as much of the phenomena that we saw was to be expected, but only if you really understand how things work. If they'd have faked it, it would've ended up looking like something out of The Matrix. |
Straw man. The reason that WTC 7 videos were kept off television, but not WTC 1 & 2, probably has to do with the fact that WTC 1 and 2 are more in accord with what a gravity driven collapse would look like. If they had made 1 and 2 look like 7, and shown that on TV, the jig would have been up from Day 1.
I hope you keep your day job, and don't switch to something like detective work.
The very things that made the troothers originally object to it as looking fishy have all been proved to be exactly what physics required.
Bald assertion. You make a good OCT'er, but your critical thinking skills are another matter.
QUOTE
If the government had been involved in faking it, some committee would've made a wrong decision someplace and it would've ended up looking like what that committee thought it *ought* to look like, and it would've been wrong.
Staw man. Isn't it convenient that government incompetence is trotted out as an explanation when that is expedient, but government competence is trotted out (e.g., in the confidence expressed in NIST's detail-free "no evidence of CD" malarkey) when that is expedient?
QUOTE (->
| QUOTE |
If the government had been involved in faking it, some committee would've made a wrong decision someplace and it would've ended up looking like what that committee thought it *ought* to look like, and it would've been wrong. |
Staw man. Isn't it convenient that government incompetence is trotted out as an explanation when that is expedient, but government competence is trotted out (e.g., in the confidence expressed in NIST's detail-free "no evidence of CD" malarkey) when that is expedient?
We've got over three hundred pages of examples of stuff that people *thought* looked wrong and none of those things panned out.
No, but please keep saying this. It shows how much we can trust you.
QUOTE
The troothers still have no Smoking Gun. How many of those things would've ended up getting past a planning committee?
While the final disposition of the thermate evidence lies with the scientific community, Professor Jones has described it as exactly that - i.e., a "smoking gun". The videographic evidence of CD is compelling, though unfortunately no comprehensive paper dealing with both concrete comminution and fluid dynamics of air/concrete/other particulate flows has been produced.
Then again, there's not been a compelling analysis of the collapse, proper, which, if were such to be done and showed that global collapse is either impossible or else would have taken much longer than observed, calculating fluid flows, etc., would be superfluous.
In short, you are a hand-waving propagandist. Correct me if I'm wrong, but have you even posted one back-of-the-envelope calculation on this thread? (Never mind anything like a careful analysis.)
I don't think so....
The general rule is that “he who asserts must prove”.
Grumpy and W C Elliott both claim that the Aircrafts alone caused the total destruction of the twin towers and WTC7.
They are, of course, the real "Troofers", because there is no physical evidence to support this claim.
I want to see proof of this. All I see is a clumsy patchwork of speculation woven into extrapolation.
Grumpy and W C Elliott both claim that the Aircrafts alone caused the total destruction of the twin towers and WTC7.
They are, of course, the real "Troofers", because there is no physical evidence to support this claim.
I want to see proof of this. All I see is a clumsy patchwork of speculation woven into extrapolation.
Not sure if this applies to waves in WTC scenario, but from
http://www.ndt.net/article/az/ut/lamb.htm
A type of ultrasonic wave propagation in which the wave is guided between two parallel surfaces of the test object. For an object sufficiently thin to allow penetration to the opposite surface, e.g. a plate having a thickness of the order of a wavelenght or so, Rayleigh waves degenerate to Lamb waves, which can be propagate in a number of modes, either symmetrical or antisymmetrical. The velocity is dependent on the product of frequency and material thickness. Lamb waves are named for Horace Lamb, in honor of his fundamental contributions to this subject. Investigation on Lamb and leaky Lamb waves have been carried out continuously since their discovery and researchers have done theoretical and experimental work for different purposes, ranging from seismology and the ship construction industry to acoustic microscopy, non-destructive testing and acoustic sensors. Synonymous terms are guided wave and plate wave.
http://www.ndt.net/article/az/ut/lamb.htm
QUOTE
A type of ultrasonic wave propagation in which the wave is guided between two parallel surfaces of the test object. For an object sufficiently thin to allow penetration to the opposite surface, e.g. a plate having a thickness of the order of a wavelenght or so, Rayleigh waves degenerate to Lamb waves, which can be propagate in a number of modes, either symmetrical or antisymmetrical. The velocity is dependent on the product of frequency and material thickness. Lamb waves are named for Horace Lamb, in honor of his fundamental contributions to this subject. Investigation on Lamb and leaky Lamb waves have been carried out continuously since their discovery and researchers have done theoretical and experimental work for different purposes, ranging from seismology and the ship construction industry to acoustic microscopy, non-destructive testing and acoustic sensors. Synonymous terms are guided wave and plate wave.
In those 300 pages there is also no proof that the force delivered by story i-1 is sufficient enough to crush story i but not to affect story i-1, the force delivered by story i+1 is of course sufficient because of the 'compacted layer of floors'
frater plecticus
http://wtc.nist.gov/
When the "troothers" get to this point they MAY be taken seriously, until then, not so much.
metamars
http://wtc.nist.gov/
When the "troothers" get to this point they MAY be taken seriously, until then, not so much.
metamars
Straw man. If the core columns are being systematically and slowly being taken out, why should load not be transferred to the perimeter, just as slowly?
It was, until something crumpled. No straw man, just simple fact.
The real strawman is saying that videos of 7 are kept off the air.
The real strawman is saying that videos of 7 are kept off the air.
Bald assertion. You make a good OCT'er, but your critical thinking skills are another matter.
It is YOUR critical thinking skills that are questionable. NIST stands, and you have yet to falsify anything in those reports. I don't think you are capable of doing so, you lack both the skills and any evidence, and you are reduced to sniping at those you cannot show to be wrong.
Bald assertion. You make a good OCT'er, but your critical thinking skills are another matter.
It is YOUR critical thinking skills that are questionable. NIST stands, and you have yet to falsify anything in those reports. I don't think you are capable of doing so, you lack both the skills and any evidence, and you are reduced to sniping at those you cannot show to be wrong.
Staw man. Isn't it convenient that government incompetence is trotted out as an explanation when that is expedient, but government competence is trotted out (e.g., in the confidence expressed in NIST's detail-free "no evidence of CD" malarkey) when that is expedient?
"The Government" is one of your biggest strawmen, lumping politicians and scientists into the same group. Well, politicos are notorious bottom feeders who would rather lie to you than tell the truth(if it is in their interest), most are incompetent at any real work.
Scientist, OTOH, base their reputation and standing on being truthful and(as Steven Jones and Ryan have found) the penalties are very severe for those who sell that reputation for political or financial gain. And the judges of that reputation are other scientists(it's called peer review for a reason). Those who fail peer review(or worse, avoid it) are not concidered serious or competent scientists.
So how many peer reviewed papers falsifying NIST's reports have you published???
Anyone else in the "troother movement???
Anyone at all???
(crickets)
Grumpy
QUOTE
They are, of course, the real "Troofers", because there is no physical evidence to support this claim.
I want to see proof of this. All I see is a clumsy patchwork of speculation woven into extrapolation.
I want to see proof of this. All I see is a clumsy patchwork of speculation woven into extrapolation.
http://wtc.nist.gov/
When the "troothers" get to this point they MAY be taken seriously, until then, not so much.
metamars
QUOTE (->
| QUOTE |
| They are, of course, the real "Troofers", because there is no physical evidence to support this claim. I want to see proof of this. All I see is a clumsy patchwork of speculation woven into extrapolation. |
http://wtc.nist.gov/
When the "troothers" get to this point they MAY be taken seriously, until then, not so much.
metamars
Straw man. If the core columns are being systematically and slowly being taken out, why should load not be transferred to the perimeter, just as slowly?
It was, until something crumpled. No straw man, just simple fact.
QUOTE
Straw man. The reason that WTC 7 videos were kept off television, but not WTC 1 & 2, probably has to do with the fact that WTC 1 and 2 are more in accord with what a gravity driven collapse would look like. If they had made 1 and 2 look like 7, and shown that on TV, the jig would have been up from Day 1.
The real strawman is saying that videos of 7 are kept off the air.
QUOTE (->
| QUOTE |
| Straw man. The reason that WTC 7 videos were kept off television, but not WTC 1 & 2, probably has to do with the fact that WTC 1 and 2 are more in accord with what a gravity driven collapse would look like. If they had made 1 and 2 look like 7, and shown that on TV, the jig would have been up from Day 1. |
The real strawman is saying that videos of 7 are kept off the air.
QUOTE
The very things that made the troothers originally object to it as looking fishy have all been proved to be exactly what physics required.
Bald assertion. You make a good OCT'er, but your critical thinking skills are another matter.
It is YOUR critical thinking skills that are questionable. NIST stands, and you have yet to falsify anything in those reports. I don't think you are capable of doing so, you lack both the skills and any evidence, and you are reduced to sniping at those you cannot show to be wrong.
QUOTE (->
| QUOTE |
| The very things that made the troothers originally object to it as looking fishy have all been proved to be exactly what physics required. |
Bald assertion. You make a good OCT'er, but your critical thinking skills are another matter.
It is YOUR critical thinking skills that are questionable. NIST stands, and you have yet to falsify anything in those reports. I don't think you are capable of doing so, you lack both the skills and any evidence, and you are reduced to sniping at those you cannot show to be wrong.
Staw man. Isn't it convenient that government incompetence is trotted out as an explanation when that is expedient, but government competence is trotted out (e.g., in the confidence expressed in NIST's detail-free "no evidence of CD" malarkey) when that is expedient?
"The Government" is one of your biggest strawmen, lumping politicians and scientists into the same group. Well, politicos are notorious bottom feeders who would rather lie to you than tell the truth(if it is in their interest), most are incompetent at any real work.
Scientist, OTOH, base their reputation and standing on being truthful and(as Steven Jones and Ryan have found) the penalties are very severe for those who sell that reputation for political or financial gain. And the judges of that reputation are other scientists(it's called peer review for a reason). Those who fail peer review(or worse, avoid it) are not concidered serious or competent scientists.
So how many peer reviewed papers falsifying NIST's reports have you published???
Anyone else in the "troother movement???
Anyone at all???
(crickets)
Grumpy
Arthur, that was indeed one-sided info from Steven E Jones.
QUOTE (einsteen+Jun 26 2007, 11:22 AM)
Arthur, that was indeed one-sided info from Steven E Jones.
Ok, (and I'm VERY pleased that you acknowledge Jone's duplicity) now do you think Jowenko could derive sufficient facts from that video to arrive at a reasonable conclusion as to the demise of WTC 7?
Is it also possible that the video we see is edited? Are there perhaps parts left out?
I say this because he seems to be a fairly intelligent man, fairly knowledgable about structures and so I find it interesting that while the NIST scientists have had to spend a LOT of time studying the data, evaluating the timeline and witness reports, reviewing the structural plans, modeling the structure, modeling the fires etc and even after all this time and effort have yet to be able to say why/how the towers fell, yet people believe that someone can look at that one video taken from the RELATIVELY UNDAMAGED side of the building and make ANY determination at all as to what actually happened (or didn't happen).
A scientific conclusion is simply not that easily arrived at.
Arthur
Ok, (and I'm VERY pleased that you acknowledge Jone's duplicity) now do you think Jowenko could derive sufficient facts from that video to arrive at a reasonable conclusion as to the demise of WTC 7?
Is it also possible that the video we see is edited? Are there perhaps parts left out?
I say this because he seems to be a fairly intelligent man, fairly knowledgable about structures and so I find it interesting that while the NIST scientists have had to spend a LOT of time studying the data, evaluating the timeline and witness reports, reviewing the structural plans, modeling the structure, modeling the fires etc and even after all this time and effort have yet to be able to say why/how the towers fell, yet people believe that someone can look at that one video taken from the RELATIVELY UNDAMAGED side of the building and make ANY determination at all as to what actually happened (or didn't happen).
A scientific conclusion is simply not that easily arrived at.
Arthur
any evidence that points to a CD is not evidence of a CD.
any eyewitness hearing bombs didn't hear bombs.
any reportedly molten metal, wasn't molten metal.
yellow hot dripping beams photographed in the clean-up are impossible, because they would melt the hydraulics.
yellow hot molten stuff pouring from the tower is easily explained as anything but a purposefully placed steel eater.
lateral explosions out the side of the building are easily explained as anything but bombs.
the FREEFALLING tower seven is easily, er, um, pretty sure that, ummmm, working on the problem, but IT JUST FELL, OKAY, due to anything but demolition!!!
all witnesses were wrong, unless they are reporting a missing side of wtc7.
there is nothing to see. move along.
-signed, the OCT.
any eyewitness hearing bombs didn't hear bombs.
any reportedly molten metal, wasn't molten metal.
yellow hot dripping beams photographed in the clean-up are impossible, because they would melt the hydraulics.
yellow hot molten stuff pouring from the tower is easily explained as anything but a purposefully placed steel eater.
lateral explosions out the side of the building are easily explained as anything but bombs.
the FREEFALLING tower seven is easily, er, um, pretty sure that, ummmm, working on the problem, but IT JUST FELL, OKAY, due to anything but demolition!!!
all witnesses were wrong, unless they are reporting a missing side of wtc7.
there is nothing to see. move along.
-signed, the OCT.
newton
What evidence??? So far, NADA!!!
What evidence??? So far, NADA!!!
any eyewitness hearing bombs didn't hear bombs.
Loud noises do not indicate bombs, they only indicate loud noises. Upon investigation no bomb evidence was found, therefore loud noises were NOT bombs.
No puddles of solidified steel were found during cleanup, so those who thought they saw molten steel either were mistaken or were exagerating to indicate great heat.
No puddles of solidified steel were found during cleanup, so those who thought they saw molten steel either were mistaken or were exagerating to indicate great heat.
yellow hot dripping beams photographed in the clean-up are impossible, because they would melt the hydraulics.
Whatever was dripping off of the steel, it was not molten steel. Any beam which is molten is no longer a beam, it is a puddle. And, yes, if the end of the crane dipped into a puddle of molten steel it would fry the hydralics, melt the hoses(rubber, remember) and start a big hydralic oil fire, if the operator was lucky he might survive.
A purposely placed steel eater is the LAST possibility in a long list of possibilities. Given the complete lack of any valid evidence it would be stupid to jump to that conclusion.
A purposely placed steel eater is the LAST possibility in a long list of possibilities. Given the complete lack of any valid evidence it would be stupid to jump to that conclusion.
lateral explosions out the side of the building are easily explained as anything but bombs.
What lateral explosions, all that can be seen on the videos is low velocity(in relation to explosives) expulsions of air.
Tower 7 fell because of the extensive damage done by debris from tower 1, the huge fuel fed fires that burned unchecked for hours and it crumbled from the south face to the east penthouse, then the west penthouse then the curtain wall. It took over 18 seconds, of which only 6-7 seconds are clearly visible.
Tower 7 fell because of the extensive damage done by debris from tower 1, the huge fuel fed fires that burned unchecked for hours and it crumbled from the south face to the east penthouse, then the west penthouse then the curtain wall. It took over 18 seconds, of which only 6-7 seconds are clearly visible.
all witnesses were wrong, unless they are reporting a missing side of wtc7.
All eyewitnesses whose story is not backed by corroborating evidence are either mistaken or lying.
Grumpy
Hi meta!
Careful there, mate.
You have just demonstrated your bias by excluding the obvious possibility if it WAS SUPPOSED TO BE a CD as you maintain.
The 'conspirators would have had an easy job of it if they merely planted explosives capable of COMPLETELY AND IMMEDIATELY 'REMOVING' the core effectiveness and DETONATING THE LOT where/when the planes HIT and THEN EXPLODED SPECTACULARLY OVER MANY FLOORS and out the sides to a great extent.
All evidence that it wasn't a CD is evidence that it was a CD + cover-up
Every loud noise is a bomb.
Anything that looks like molten metal is evidence of thermate/thermite
Yellow hot dripping beams is automatically evidence that the government conspired to kill thousands of people (nevermind the fire)
Yellow hot molten stuff is automatically thermate/thermite, nevermind all the lead in the batteries in the Uninterruptible Power Supplies on that floor
Any puff of smoke is automatically evidence of explosives going off (nevermind the fact that explosives produce supersonic shockwaves, and the smoke is exiting the building at the speed you'd expect if the floor above it was collapsing
Anything having to do with WTC7 couldn't possibly be due to the raging fire that lasted hours or the cantilevered foundation or any of the other sensible explanations.
Furthermore:
Every car that's behind you is driven by a government agent.
Anyone who isn't interested in Revolution is a shape-shifting Nazi lizard.
Signed,
Troothers
QUOTE
any evidence that points to a CD is not evidence of a CD.
What evidence??? So far, NADA!!!
QUOTE (->
| QUOTE |
| any evidence that points to a CD is not evidence of a CD. |
What evidence??? So far, NADA!!!
any eyewitness hearing bombs didn't hear bombs.
Loud noises do not indicate bombs, they only indicate loud noises. Upon investigation no bomb evidence was found, therefore loud noises were NOT bombs.
QUOTE
any reportedly molten metal, wasn't molten metal.
No puddles of solidified steel were found during cleanup, so those who thought they saw molten steel either were mistaken or were exagerating to indicate great heat.
QUOTE (->
| QUOTE |
| any reportedly molten metal, wasn't molten metal. |
No puddles of solidified steel were found during cleanup, so those who thought they saw molten steel either were mistaken or were exagerating to indicate great heat.
yellow hot dripping beams photographed in the clean-up are impossible, because they would melt the hydraulics.
Whatever was dripping off of the steel, it was not molten steel. Any beam which is molten is no longer a beam, it is a puddle. And, yes, if the end of the crane dipped into a puddle of molten steel it would fry the hydralics, melt the hoses(rubber, remember) and start a big hydralic oil fire, if the operator was lucky he might survive.
QUOTE
yellow hot molten stuff pouring from the tower is easily explained as anything but a purposefully placed steel eater.
A purposely placed steel eater is the LAST possibility in a long list of possibilities. Given the complete lack of any valid evidence it would be stupid to jump to that conclusion.
QUOTE (->
| QUOTE |
| yellow hot molten stuff pouring from the tower is easily explained as anything but a purposefully placed steel eater. |
A purposely placed steel eater is the LAST possibility in a long list of possibilities. Given the complete lack of any valid evidence it would be stupid to jump to that conclusion.
lateral explosions out the side of the building are easily explained as anything but bombs.
What lateral explosions, all that can be seen on the videos is low velocity(in relation to explosives) expulsions of air.
QUOTE
the FREEFALLING tower seven is easily, er, um, pretty sure that, ummmm, working on the problem, but IT JUST FELL, OKAY, due to anything but demolition!!!
Tower 7 fell because of the extensive damage done by debris from tower 1, the huge fuel fed fires that burned unchecked for hours and it crumbled from the south face to the east penthouse, then the west penthouse then the curtain wall. It took over 18 seconds, of which only 6-7 seconds are clearly visible.
QUOTE (->
| QUOTE |
| the FREEFALLING tower seven is easily, er, um, pretty sure that, ummmm, working on the problem, but IT JUST FELL, OKAY, due to anything but demolition!!! |
Tower 7 fell because of the extensive damage done by debris from tower 1, the huge fuel fed fires that burned unchecked for hours and it crumbled from the south face to the east penthouse, then the west penthouse then the curtain wall. It took over 18 seconds, of which only 6-7 seconds are clearly visible.
all witnesses were wrong, unless they are reporting a missing side of wtc7.
All eyewitnesses whose story is not backed by corroborating evidence are either mistaken or lying.
Grumpy
Grumpy, if it is true, what kind of evidence would convince you ? I understand you have your demands on a higher level but what would convince you ?
lozenge124 --- Yesterday I computed an approximation to the slenderness ratio of a hypothetical building consisting just of the exterior walls. I compute 31.2, probably an underestimate. It might be as high as 60 or even 70. However, the critical slenderness ratio for Euler buckling is 99.3.
So, provided the wind does not blow hard, this hypothetical building ought to stand up on its own.
So, provided the wind does not blow hard, this hypothetical building ought to stand up on its own.
ok, this is nitpicking but would a theoretical column not always stand on its own as long as the pressure wil not break it... from the material of the mount everest you could theoretically build a 5 km high column... Of course a very small movement would break it...
einsteen
I've listed what I would consider valid evidence before.
Start with shaped charge channels. These are square section strips of steel, open on one side. They hold an explosives charge topped by a V shaped strip of pure copper. They are strapped to beams, open(copper) side to the steel and direct the explosion to form a wedge shaped jet of copper plasma into the steel, cutting that steel. THE CHANNELS ALWAYS SURVIVE, usually in near pristine condition. No one experienced in CD would miss seeing them. Which brings me to number two.
All steel cut by this type of charge have a clean edge (cleaner than you can cut with a torch) with copper colored edges. It will not rust at the very edge due to this copper coating. It is very distinctive and not to be missed by any experienced workers. Also, steel cut by explosives has a distinct type of stippling, similar to a contact burn from a gun barrel placed against the skin. No steel with such stippling was found.
Timers, detonators, det cord residue, wires, radio detonators. Having, in my youth, worked on a drill crew in road construction, I know that the first job we had to do after every shot was to clean up the electrical or detcord wires, they are a mess and will wrap around an axle of a loader(for instance) destroying the axle seals, if nothing else. It also helps identify and isolate any of the holes where the charge did not go off. Even det cord leaves yards of ruptured plastic tubing leading from the detonator to every charge. Again, a dead giveaway of explosives use. The maze of wiring would be evidence, along with detonators, etc. Got any???
Chemical residues. All current demo explosives leave distinctive odors and residues behind. Dogs have extremely good noses and would alert on these types of odors, they did not find one single indication of explosives, that is good enough for me.
This is just a partial list, there would be many more indicators of the use of explosives that the professionals in CD who helped clean up ground zero WOULD HAVE FOUND if explosives were employed, yet none were found.
And thermite/thermate are a waste of time, they are useless in CD unless you just want a hole straight down through something(say, an engine block or the bottom of a boat).
The more you know about 911, the more you know it was not a CD.
Grumpy
I've listed what I would consider valid evidence before.
Start with shaped charge channels. These are square section strips of steel, open on one side. They hold an explosives charge topped by a V shaped strip of pure copper. They are strapped to beams, open(copper) side to the steel and direct the explosion to form a wedge shaped jet of copper plasma into the steel, cutting that steel. THE CHANNELS ALWAYS SURVIVE, usually in near pristine condition. No one experienced in CD would miss seeing them. Which brings me to number two.
All steel cut by this type of charge have a clean edge (cleaner than you can cut with a torch) with copper colored edges. It will not rust at the very edge due to this copper coating. It is very distinctive and not to be missed by any experienced workers. Also, steel cut by explosives has a distinct type of stippling, similar to a contact burn from a gun barrel placed against the skin. No steel with such stippling was found.
Timers, detonators, det cord residue, wires, radio detonators. Having, in my youth, worked on a drill crew in road construction, I know that the first job we had to do after every shot was to clean up the electrical or detcord wires, they are a mess and will wrap around an axle of a loader(for instance) destroying the axle seals, if nothing else. It also helps identify and isolate any of the holes where the charge did not go off. Even det cord leaves yards of ruptured plastic tubing leading from the detonator to every charge. Again, a dead giveaway of explosives use. The maze of wiring would be evidence, along with detonators, etc. Got any???
Chemical residues. All current demo explosives leave distinctive odors and residues behind. Dogs have extremely good noses and would alert on these types of odors, they did not find one single indication of explosives, that is good enough for me.
This is just a partial list, there would be many more indicators of the use of explosives that the professionals in CD who helped clean up ground zero WOULD HAVE FOUND if explosives were employed, yet none were found.
And thermite/thermate are a waste of time, they are useless in CD unless you just want a hole straight down through something(say, an engine block or the bottom of a boat).
The more you know about 911, the more you know it was not a CD.
Grumpy
QUOTE (einsteen+Jun 26 2007, 09:07 PM)
ok[sic], this is nitpicking but would a theoretical column not always stand on its own as long as the pressure wil[sic] not break it... from the material of the mount everest you could theoretically build a 5 km high column... Of course a very small movement would break it...
No, a slender enough column will buckle under its own weight. See Wikipedia about buckling.
No, a slender enough column will buckle under its own weight. See Wikipedia about buckling.
QUOTE (metamars to wcelliot+Jun 26 2007, 02:53 PM)
Straw man. If the core columns are being systematically and slowly being taken out, why should load not be transferred to the perimeter, just as slowly?
Straw man. The reason that WTC 7 videos were kept off television, but not WTC 1 & 2, probably has to do with the fact that WTC 1 and 2 are more in accord with what a gravity driven collapse would look like. If they had made 1 and 2 look like 7, and shown that on TV, the jig would have been up from Day 1.
I hope you keep your day job, and don't switch to something like detective work.
Bald assertion. You make a good OCT'er, but your critical thinking skills are.
.....
....
Hi meta!
Careful there, mate.
You have just demonstrated your bias by excluding the obvious possibility if it WAS SUPPOSED TO BE a CD as you maintain.
The 'conspirators would have had an easy job of it if they merely planted explosives capable of COMPLETELY AND IMMEDIATELY 'REMOVING' the core effectiveness and DETONATING THE LOT where/when the planes HIT and THEN EXPLODED SPECTACULARLY OVER MANY FLOORS and out the sides to a great extent.
Perfect for a 'conspiracy' explosive-demolition 'cover up'.
Such an initial plane impact/explosion as we saw would have 'hidden' any explosion of ENOUGH CD charges to 'take out' the core THERE AND THEN and caused immediate collapse of the top 'box'......without needing to 'conspire' to do it SLOWLY at all!
So, how about using your OWN much vaunted 'critical thinking skills' to posit why CD 'conspirators' didn't go for the simple immediate collapse route rather than go to all the trouble, complexity and risk of exposure by going the convoluted SLOW route to that CD that you say was 'systematic' and 'slowly'.
I know that if it were I doing the 'job', I would use the spectacular plane impact and HUMONGOUS FUEL EXPLOSION AND IMMEDIATE WIDESPREAD FIRE to IMMEDIATELY set off my explosives under that 'cover'....and immediately bring down the 'top section' onto the 'bottom section' and wait for any 'bonus' damage/collapse.
Think about it: the fact that it DID happen so 'slowly' in all cases, points to the fact that it was NOT 'controlled' AT ALL!
And while you are using your 'critical thinking skills', perhaps you might want to GO AND ASK all those 'schedulers' and 'library footage' people at the TV networks WHY they CHOOSE to use the more spectacular and familiar images of WTC1 & 2 (in preference to that of WTC7) every time 9/11 news/documentary items are compiled for their TV programs. Simple and direct way to answer your doubts there, isn't it?
Cheers!....and good luck with that 'bias' problem mate.....it'll compromise your 'critical thinking skills' EVERY TIME if you don't watch out! hehehe.
Bye all!
RC.
.
Straw man. The reason that WTC 7 videos were kept off television, but not WTC 1 & 2, probably has to do with the fact that WTC 1 and 2 are more in accord with what a gravity driven collapse would look like. If they had made 1 and 2 look like 7, and shown that on TV, the jig would have been up from Day 1.
I hope you keep your day job, and don't switch to something like detective work.
Bald assertion. You make a good OCT'er, but your critical thinking skills are.
.....
....
Hi meta!
Careful there, mate.
You have just demonstrated your bias by excluding the obvious possibility if it WAS SUPPOSED TO BE a CD as you maintain.
The 'conspirators would have had an easy job of it if they merely planted explosives capable of COMPLETELY AND IMMEDIATELY 'REMOVING' the core effectiveness and DETONATING THE LOT where/when the planes HIT and THEN EXPLODED SPECTACULARLY OVER MANY FLOORS and out the sides to a great extent.
Perfect for a 'conspiracy' explosive-demolition 'cover up'.
Such an initial plane impact/explosion as we saw would have 'hidden' any explosion of ENOUGH CD charges to 'take out' the core THERE AND THEN and caused immediate collapse of the top 'box'......without needing to 'conspire' to do it SLOWLY at all!
So, how about using your OWN much vaunted 'critical thinking skills' to posit why CD 'conspirators' didn't go for the simple immediate collapse route rather than go to all the trouble, complexity and risk of exposure by going the convoluted SLOW route to that CD that you say was 'systematic' and 'slowly'.
I know that if it were I doing the 'job', I would use the spectacular plane impact and HUMONGOUS FUEL EXPLOSION AND IMMEDIATE WIDESPREAD FIRE to IMMEDIATELY set off my explosives under that 'cover'....and immediately bring down the 'top section' onto the 'bottom section' and wait for any 'bonus' damage/collapse.
Think about it: the fact that it DID happen so 'slowly' in all cases, points to the fact that it was NOT 'controlled' AT ALL!
And while you are using your 'critical thinking skills', perhaps you might want to GO AND ASK all those 'schedulers' and 'library footage' people at the TV networks WHY they CHOOSE to use the more spectacular and familiar images of WTC1 & 2 (in preference to that of WTC7) every time 9/11 news/documentary items are compiled for their TV programs. Simple and direct way to answer your doubts there, isn't it?
Cheers!....and good luck with that 'bias' problem mate.....it'll compromise your 'critical thinking skills' EVERY TIME if you don't watch out! hehehe.
Bye all!
RC.
.
The following setup is related to the question of how pressure pulses would travel down and up core columns. We treat the question as a standing wave problem.
Consider an ideal spring of stiffness k_1 suspended from a support with a mass M_1 attached at the bottom. To the bottom of mass M_1 is attached another ideal spring of stiffness k_2 (less or equal to k_1) and to the bottom of that is attached a mass M_2 (less than or equal to M_1). Force the system to come to rest. Now add to M_2 a small mass m. Describe, qualitatively, the motion of (M_2+m) in the vertical direction.
Repeat for a system with 40 masses, M_1, ..., M_40, with the small mass m added to M_40.
Consider an ideal spring of stiffness k_1 suspended from a support with a mass M_1 attached at the bottom. To the bottom of mass M_1 is attached another ideal spring of stiffness k_2 (less or equal to k_1) and to the bottom of that is attached a mass M_2 (less than or equal to M_1). Force the system to come to rest. Now add to M_2 a small mass m. Describe, qualitatively, the motion of (M_2+m) in the vertical direction.
Repeat for a system with 40 masses, M_1, ..., M_40, with the small mass m added to M_40.
QUOTE (RealityCheck+Jun 26 2007, 10:02 PM)
Hi meta!
Careful there, mate.
You have just demonstrated your bias by excluding the obvious possibility if it WAS SUPPOSED TO BE a CD as you maintain.
The 'conspirators would have had an easy job of it if they merely planted explosives capable of COMPLETELY AND IMMEDIATELY 'REMOVING' the core effectiveness and DETONATING THE LOT where/when the planes HIT and THEN EXPLODED SPECTACULARLY OVER MANY FLOORS and out the sides to a great extent.
I think an easier CD scenario would be to take out a high enough percentage of the floor connections on a given floor, and drop an entire floor system to start a progressive collapse in the impact area.
QUOTE (Capracus+Jun 26 2007, 11:03 PM)
I think an easier CD scenario would be to take out a high enough percentage of the floor connections on a given floor, and drop an entire floor system to start a progressive collapse in the impact area.
Hi Cap!
Yes, it would be 'easier', hehehe....but it would still be SLOWER than removing the core at the impact levels....and that's the whole point of my suggestion....that ANY 'slowness' that takes the collapse event OUTSIDE the immediate plane impact/explosion 'cover zone' duration will be more likely to 'risk discovery' than if the CD charges removed the core at the time the planes hit/exploded.
See what I mean? Any SLOW 'excursions' from that critical 'cover' invites problems because THEN there is a 'viewing window' for observers to actually further examine the processes. Whereas if it was 'all over' WITHIN the time span of the plane impact/explosion, it would be practically impossible to 'separate' what did what to what and when in that initial fireball.
Of course, either way, it still leaves the necessity to find 'traces' of such CD explosives, whatever the 'deployment/detonation' procedures for same. hehehe.
But it would be less likely to attract the troofer 'conspiracy mob' IN THE FIRST PLACE if the core had been removed at the same time as the impact/explosion! And we would not be having these discussions.
So ironically, the troofers have to thank the fact that it was NOT 'a CD conspiracy' so that they could have any 'leeway at all' to accuse that it WAS one!
Oh what fun! (not really).
Cheers all!
RC.
.
Hi Cap!
Yes, it would be 'easier', hehehe....but it would still be SLOWER than removing the core at the impact levels....and that's the whole point of my suggestion....that ANY 'slowness' that takes the collapse event OUTSIDE the immediate plane impact/explosion 'cover zone' duration will be more likely to 'risk discovery' than if the CD charges removed the core at the time the planes hit/exploded.
See what I mean? Any SLOW 'excursions' from that critical 'cover' invites problems because THEN there is a 'viewing window' for observers to actually further examine the processes. Whereas if it was 'all over' WITHIN the time span of the plane impact/explosion, it would be practically impossible to 'separate' what did what to what and when in that initial fireball.
Of course, either way, it still leaves the necessity to find 'traces' of such CD explosives, whatever the 'deployment/detonation' procedures for same. hehehe.
But it would be less likely to attract the troofer 'conspiracy mob' IN THE FIRST PLACE if the core had been removed at the same time as the impact/explosion! And we would not be having these discussions.
So ironically, the troofers have to thank the fact that it was NOT 'a CD conspiracy' so that they could have any 'leeway at all' to accuse that it WAS one!
Oh what fun! (not really).
Cheers all!
RC.
.
QUOTE (RealityCheck+Jun 26 2007, 11:38 PM)
Of course, either way, it still leaves the necessity to find 'traces' of such CD explosives, whatever the 'deployment/detonation' procedures for same. hehehe.
Speaking of finding traces, it's too bad that a federal building disaster investigation policy wasn't in place at the time of the Twin Tower collapses, it would have made for a more thorough investigation with a lot more supportive evidence.
QUOTE
But it would be less likely to attract the troofer 'conspiracy mob' IN THE FIRST PLACE if the core had been removed at the same time as the impact/explosion! And we would not be having these discussions.
We may not be having this particular discussion, but seeing how these conspiracy types operate, I'm sure they would find some obscure bit to blow completely out of proportion, and ignite a discussion of another kind. QUOTE (David B. Benson+Jun 26 2007, 10:30 PM)
The following setup is related to the question of how pressure pulses would travel down and up core columns. We treat the question as a standing wave problem.
Consider an ideal spring of stiffness k_1 suspended from a support with a mass M_1 attached at the bottom. To the bottom of mass M_1 is attached another ideal spring of stiffness k_2 (less or equal to k_1) and to the bottom of that is attached a mass M_2 (less than or equal to M_1). Force the system to come to rest. Now add to M_2 a small mass m. Describe, qualitatively, the motion of (M_2+m) in the vertical direction.
Repeat for a system with 40 masses, M_1, ..., M_40, with the small mass m added to M_40.
Well then, I'll try.
For the two mass system there are two characteristic frequencies. The lowest mass will oscillate, sinusoidally, at a superposition of both.
For the forty mass system, there are forty characteristic frequencies. The lowest mass will will oscillate at a superposition of all forty.
Now suppose that each higher mass is only slightly more massive than the one just below and that the spring stiffnesses are all equal. This ought to provide a reasonable, but upside down, model for a core column. Describe, qualitatively, the vertical motion of the lowest mass of the forty.
Consider an ideal spring of stiffness k_1 suspended from a support with a mass M_1 attached at the bottom. To the bottom of mass M_1 is attached another ideal spring of stiffness k_2 (less or equal to k_1) and to the bottom of that is attached a mass M_2 (less than or equal to M_1). Force the system to come to rest. Now add to M_2 a small mass m. Describe, qualitatively, the motion of (M_2+m) in the vertical direction.
Repeat for a system with 40 masses, M_1, ..., M_40, with the small mass m added to M_40.
Well then, I'll try.
For the two mass system there are two characteristic frequencies. The lowest mass will oscillate, sinusoidally, at a superposition of both.
For the forty mass system, there are forty characteristic frequencies. The lowest mass will will oscillate at a superposition of all forty.
Now suppose that each higher mass is only slightly more massive than the one just below and that the spring stiffnesses are all equal. This ought to provide a reasonable, but upside down, model for a core column. Describe, qualitatively, the vertical motion of the lowest mass of the forty.
QUOTE (Capracus+Jun 27 2007, 12:44 AM)
Speaking of finding traces, it's too bad that a federal building disaster investigation policy wasn't in place at the time of the Twin Tower collapses, it would have made for a more thorough investigation with a lot more supportive evidence.
We may not be having this particular discussion, but seeing how these conspiracy types operate, I'm sure they would find some obscure bit to blow completely out of proportion, and ignite a discussion of another kind.
Hehehe.
I note your use of 'incendiary' language, Cap! hehehe.
Careful!...or some 'troofer' will come on and claim they 'heard an explosion' when they read your post! hahaha!
Anyway, even if they tried to 'grasp at straws' to accuse, there would have been little for them to 'see' in the videos in my scenario.....other than a big plane impact/explosion and an almost immediate collapse.
And if they DID say that explosives were ALSO involved, even in THAT scenario, then the onus would be even MORE pronounced on them to provide evidence of same IN THAT scenario....which would be hard to do if any 'core removing' CD explosion and immediate collapse THEN was 'covered' by the initial impact/explosion!
And of course, they would still have the problem of CD 'traces' to 'discover'....which they have failed to do, even in the ACTUAL PROLONGED AND SLOW uncontrolled events, hehehe.
So nah, mate...conspiracy accusations would have sounded even more flaky...if that were possible.
Cheers mate!
RC.
.
We may not be having this particular discussion, but seeing how these conspiracy types operate, I'm sure they would find some obscure bit to blow completely out of proportion, and ignite a discussion of another kind.
Hehehe.
I note your use of 'incendiary' language, Cap! hehehe.
Careful!...or some 'troofer' will come on and claim they 'heard an explosion' when they read your post! hahaha!
Anyway, even if they tried to 'grasp at straws' to accuse, there would have been little for them to 'see' in the videos in my scenario.....other than a big plane impact/explosion and an almost immediate collapse.
And if they DID say that explosives were ALSO involved, even in THAT scenario, then the onus would be even MORE pronounced on them to provide evidence of same IN THAT scenario....which would be hard to do if any 'core removing' CD explosion and immediate collapse THEN was 'covered' by the initial impact/explosion!
And of course, they would still have the problem of CD 'traces' to 'discover'....which they have failed to do, even in the ACTUAL PROLONGED AND SLOW uncontrolled events, hehehe.
So nah, mate...conspiracy accusations would have sounded even more flaky...if that were possible.
Cheers mate!
RC.
.
QUOTE
any evidence that points to a CD is not evidence of a CD.
any eyewitness hearing bombs didn't hear bombs.
any reportedly molten metal, wasn't molten metal.
yellow hot dripping beams photographed in the clean-up are impossible, because they would melt the hydraulics.
yellow hot molten stuff pouring from the tower is easily explained as anything but a purposefully placed steel eater.
lateral explosions out the side of the building are easily explained as anything but bombs.
the FREEFALLING tower seven is easily, er, um, pretty sure that, ummmm, working on the problem, but IT JUST FELL, OKAY, due to anything but demolition!!!
all witnesses were wrong, unless they are reporting a missing side of wtc7.
any eyewitness hearing bombs didn't hear bombs.
any reportedly molten metal, wasn't molten metal.
yellow hot dripping beams photographed in the clean-up are impossible, because they would melt the hydraulics.
yellow hot molten stuff pouring from the tower is easily explained as anything but a purposefully placed steel eater.
lateral explosions out the side of the building are easily explained as anything but bombs.
the FREEFALLING tower seven is easily, er, um, pretty sure that, ummmm, working on the problem, but IT JUST FELL, OKAY, due to anything but demolition!!!
all witnesses were wrong, unless they are reporting a missing side of wtc7.
All evidence that it wasn't a CD is evidence that it was a CD + cover-up
Every loud noise is a bomb.
Anything that looks like molten metal is evidence of thermate/thermite
Yellow hot dripping beams is automatically evidence that the government conspired to kill thousands of people (nevermind the fire)
Yellow hot molten stuff is automatically thermate/thermite, nevermind all the lead in the batteries in the Uninterruptible Power Supplies on that floor
Any puff of smoke is automatically evidence of explosives going off (nevermind the fact that explosives produce supersonic shockwaves, and the smoke is exiting the building at the speed you'd expect if the floor above it was collapsing
Anything having to do with WTC7 couldn't possibly be due to the raging fire that lasted hours or the cantilevered foundation or any of the other sensible explanations.
Furthermore:
Every car that's behind you is driven by a government agent.
Anyone who isn't interested in Revolution is a shape-shifting Nazi lizard.
Signed,
Troothers
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