QUOTE (David B. Benson+Apr 29 2007, 12:31 PM)
The assumptions have been checked and the crush-down equations validated.
It is a theory in the sense that not all details are considered. That is true of Newton's laws as well.
The assumptions are not validated else they need not be called assumptions. A model's
weaknesses are found in an honest assessment of its assumptions. Your disinterest in this assessment shows your bias.
It is a theory in the sense that not all details are considered. That is true of Newton's laws as well.
The assumptions are not validated else they need not be called assumptions. A model's
weaknesses are found in an honest assessment of its assumptions. Your disinterest in this assessment shows your bias.
QUOTE (eigenvalue+Apr 29 2007, 09:05 PM)
The assumptions are not validated else they need not be called assumptions. A model's weaknesses are found in an honest assessment of its assumptions.
The assumptions might also be called simplifying hypotheses. B & V have four, sharing the first three with Greening. I am prepared to defend all four, especially after demonstrating that the B & V crush-down equation gives answers closely agreeing with actual data.
Metamars only objection was, essentially, the constitutive character of the resulting equations. I suppose he then also objects to Hook's Law since it is also constitutive in character.
But bring forth your objections and I'll deal with each one.
The assumptions might also be called simplifying hypotheses. B & V have four, sharing the first three with Greening. I am prepared to defend all four, especially after demonstrating that the B & V crush-down equation gives answers closely agreeing with actual data.
Metamars only objection was, essentially, the constitutive character of the resulting equations. I suppose he then also objects to Hook's Law since it is also constitutive in character.
But bring forth your objections and I'll deal with each one.
QUOTE (adoucette+Apr 29 2007, 12:02 PM)
I didn't expect you'd have much to say about this.
Considering the amount of tilt TO THE SOUTH (directly away from the video) that is CLEARLY shown in NIST NCSTAR 1-6 Fig 6-7 - middle picture, and the fact that that amount of tilt didn't happen INSTANTANEOUSLY, it is ENTIRELY CONSISTENT with seeing the movement of the antenna ONE FRAME before movement of the building is seen, in a video taken PARALLEL to the motion of the tower.
Arthur
Why say anything about it?
OK -- since you press me...
If I had said anything, it would have been, "NIST and you are wrong."
Feel better now?
AND BEHOLD
A VOICE OUT OF THE HEAVENS SAYING
THIS IS MY BELOVED SON
Considering the amount of tilt TO THE SOUTH (directly away from the video) that is CLEARLY shown in NIST NCSTAR 1-6 Fig 6-7 - middle picture, and the fact that that amount of tilt didn't happen INSTANTANEOUSLY, it is ENTIRELY CONSISTENT with seeing the movement of the antenna ONE FRAME before movement of the building is seen, in a video taken PARALLEL to the motion of the tower.
Arthur
Why say anything about it?
OK -- since you press me...
If I had said anything, it would have been, "NIST and you are wrong."
Feel better now?
AND BEHOLD
A VOICE OUT OF THE HEAVENS SAYING
THIS IS MY BELOVED SON
Arthur --- Where in NCSTAR1 do I find the data which allows me to compute the window area of each office floor?
Thanks.
Thanks.
QUOTE (David B. Benson+Apr 29 2007, 05:12 PM)
Arthur --- Where in NCSTAR1 do I find the data which allows me to compute the window area of each office floor?
Thanks.
In NIST NCSTAR 1-5A Sec 4.2.2 Tower Curtain Walls and Interior Finish
"Window Glass was mounted inside the 21 1/4" X 7'5" openings in the Aluminum Curtain wall. A 1" wide aluminum widow frame attached to the columns and spandrals held 1/4" bronze tinted glass"
There were 58 windows on each side of the tower, 232 per floor.
This is 13.13 sq ft per window
For ease of use/memory: 13 sq ft per window 750 sq ft per wall, 3,000 sq ft per floor
Also in 1-5A fig 5.5 shows a properly scaled diagram of a face of the towers.
Arthur
Thanks.
In NIST NCSTAR 1-5A Sec 4.2.2 Tower Curtain Walls and Interior Finish
"Window Glass was mounted inside the 21 1/4" X 7'5" openings in the Aluminum Curtain wall. A 1" wide aluminum widow frame attached to the columns and spandrals held 1/4" bronze tinted glass"
There were 58 windows on each side of the tower, 232 per floor.
This is 13.13 sq ft per window
For ease of use/memory: 13 sq ft per window 750 sq ft per wall, 3,000 sq ft per floor
Also in 1-5A fig 5.5 shows a properly scaled diagram of a face of the towers.
Arthur
Thank you for the prompt and timely response! 
QUOTE (David B. Benson+Apr 29 2007, 07:41 PM)
Collapsed structures include
Pyramid at Meidum
Goch Cathedral
Venice Campenile
Pavia Civic Center
New World Hotel, Singapore
2000 Commonwealth Ave. tower, Boston
Ronan Points Apartments, UK
Murrah Federal Building, OK
many, many structures due to earthquakes in Armenia, Turkey, Mexico,
etc., etc.
Quoting from Bazant Verdure I see. They are actually pretty poor examples:
I posted Ronan earlier:
Here's 2000 Commonwealth Ave:
In both cases the buildings are still standing! Same for Murrah Fed building after Rider truck exploded. It absolutely stuns me that B&V use these as examples, they are completely irrelevant.
The WTC "progressive" collapse resulted in the entire building being leveled - that's what we are looking for. Your sweeping claim "The vast majority of the world's stock of large structures, steel or concrete, will undergo progressive collapse once sufficiently damaged." is false if we are talking about WTC style "progressive" collapses.
Not to say that progressive collapses never happen, but let's see a model or virtual model that exhibits such a behavior if it is so easy to get them. If you spend some time trying to design such a model you will find that you have to design it very carefully for it to do so - most of the times it won't.
And in any case, even if all the B&V examples were true progressive collapses, it's not enough to list a few buildings to prove the statement "The vast majority of the world's stock of large structures, steel or concrete, will undergo progressive collapse once sufficiently damaged."
Pyramid at Meidum
Goch Cathedral
Venice Campenile
Pavia Civic Center
New World Hotel, Singapore
2000 Commonwealth Ave. tower, Boston
Ronan Points Apartments, UK
Murrah Federal Building, OK
many, many structures due to earthquakes in Armenia, Turkey, Mexico,
etc., etc.
Quoting from Bazant Verdure I see. They are actually pretty poor examples:
I posted Ronan earlier:
Here's 2000 Commonwealth Ave:
In both cases the buildings are still standing! Same for Murrah Fed building after Rider truck exploded. It absolutely stuns me that B&V use these as examples, they are completely irrelevant.
The WTC "progressive" collapse resulted in the entire building being leveled - that's what we are looking for. Your sweeping claim "The vast majority of the world's stock of large structures, steel or concrete, will undergo progressive collapse once sufficiently damaged." is false if we are talking about WTC style "progressive" collapses.
Not to say that progressive collapses never happen, but let's see a model or virtual model that exhibits such a behavior if it is so easy to get them. If you spend some time trying to design such a model you will find that you have to design it very carefully for it to do so - most of the times it won't.
And in any case, even if all the B&V examples were true progressive collapses, it's not enough to list a few buildings to prove the statement "The vast majority of the world's stock of large structures, steel or concrete, will undergo progressive collapse once sufficiently damaged."
QUOTE (lozenge124+Apr 30 2007, 12:50 AM)
Quoting from Bazant Verdure I see.
It absolutely stuns me that B&V use these as examples, ...
The pyramid at Meidum is not from B&V.
Structural engineers have a definition of progressive collapse, may be better called disproportionate collapse. All of the examples cited meet the definition.
Perhaps what you need to write, then, is total progressive collapse.
If so, here are three more examples for you:
Rouen Cathedral (first try)
Rouen Cathedral (second try)
Rouen Cathedral (third try)
The fourth try is still standing.
It absolutely stuns me that B&V use these as examples, ...
The pyramid at Meidum is not from B&V.
Structural engineers have a definition of progressive collapse, may be better called disproportionate collapse. All of the examples cited meet the definition.
Perhaps what you need to write, then, is total progressive collapse.
If so, here are three more examples for you:
Rouen Cathedral (first try)
Rouen Cathedral (second try)
Rouen Cathedral (third try)
The fourth try is still standing.
False flag attack on California freeway bridge. Officials blame collapse on tanker truck fire. A closer look will undoubtedly reveal sabotage, because we all know that fire cannot destroy a steel and concrete structure.
Fooey! I forgot to preview the above message and the link is broken. I'll do better this time.
Scroll down to WTC
for a series of amazing LIDAR and photographic images.
Ground Zero Temporal Thermal Progression
Scroll down to WTC
for a series of amazing LIDAR and photographic images.
Ground Zero Temporal Thermal Progression
The criticalthinker cannot take the 9-11 lie any longer!
I once saw an episode of Columbo where DISPROVED that man died of natural causes, because his shoe laces were not tied from the man's perspective, but from the perspective like that of a mother tying a child's shoes, therefore no spin doctor nor lying expert can convince CRITICAL THINKING people that the man tied his own shoes before dying.
h t t p : / / 9 1 1 r e s e a r c h . w t c 7 . n e t / w t c / e v i d e n c e / p h o t o s / s t r e e t s 1 . h t m l
The 50 micron 45% silicon fine powder in the above link DISPROVES that the WTC was demolished by gravity energy, because there is no other way than explosive energy to created such a fine silicon powder from intact concrete and glass in the less than 15 seconds that the WTC towers went from whole to pieces, therefore no spin doctor nor lying expert can convince CRITICAL THINKING people that the WTC was demolished by gravity energy.
Everyone is familiar with shoe TYING, so the DISPROOF cannot be ignored, while only people educated in engineering such as myself are familiar with material MILLING, so the DISPROOF is ignored.
If you go to an engineering school or concrete manufacturer and watch them fail concrete an INTACT piece of concrete, you will notice that it breaks into sand sized particles, and in order to turn it into a 50 micron fine powder you would have to MILL those particles.
Even if you drop concrete from 30,000 jet crusing altitude, it will still fail into sand size particles, just like you cannot make flour from wheat kernels by dropping them off a tall building!
Even if you put more tha X pounds of weight on a cubic inch of concrete that has a compression strength X pounds per inch, it will still fail into sand size particles, just like you cannot make flour from wheat kernels by setting them under a heavy rock!
The reason you cannot make fine powders simply by dropping material, is that the material's collision with the ground results in the small particles recoiling upward instead of them being breaking into smaller and smaller pieces, no matter how much FORCE they hit the ground with.
The reason you cannot make fine powders simply by setting weight on material, is that the surfaces are not perfectly even, so small particles lay in the hills and the valleys between the surfaces, therefore they CANNOT be broken into smaller particles because NO FORCE is being applied to them, no matter how much FORCE is being applied to surfaces.
MILLING can be done by the scraping of abrasives which chew off one fine powder particle at a time, or done by the crushing of surfaces that are SMOOTHER than the desired fine powder particle size.
Since the environment in the demolished WTC towers was not like a MILL, and MILLING always takes more than 15 seconds to generate an appreciable amount of fine powder, WE KNOW FOR A FACT THAT THE 50 MICRON 45% SILICON FINE POWDER THAT IS GIVING THE FIRST RESPONDERS SILICOSIS LUNG DISEASE HAD TO BE CREATED BY EXPLOSIVES, BECAUSE THERE IS NO OTHER WAY FOR THAT POWDER TO BE CREATED IN THE TIME AND ENVIRONMENT OF A DEMOLISHING WTC TOWER.
I will give my house, car, money, clothes, and every worldly possession to the first person lying expert or otherwise who can turn an intact piece of concrete or glass into a 50 micron fine powder in less than 15 seconds without explosives, even though they would not need my money, because they will have won a Nobel prize and would have a zillion dollar patent for making milling obsolete!
So if you choose to believe the official LIE, and ignore the TRUTH that the WTC towers were brought down with explosives, by IGNORING the IRRFUTABLE evidence that the critical thinker has given you, it simply means your emotions overrule your logic, and your psyche cannot handle the ramifications of this IRRFUTABLE evidence, so you close your eyes and keep believing that it was not an inside job when the evidence OBVIOUSLY says otherwise to CRITICAL THINKING people like Columbo.
I once saw an episode of Columbo where DISPROVED that man died of natural causes, because his shoe laces were not tied from the man's perspective, but from the perspective like that of a mother tying a child's shoes, therefore no spin doctor nor lying expert can convince CRITICAL THINKING people that the man tied his own shoes before dying.
h t t p : / / 9 1 1 r e s e a r c h . w t c 7 . n e t / w t c / e v i d e n c e / p h o t o s / s t r e e t s 1 . h t m l
The 50 micron 45% silicon fine powder in the above link DISPROVES that the WTC was demolished by gravity energy, because there is no other way than explosive energy to created such a fine silicon powder from intact concrete and glass in the less than 15 seconds that the WTC towers went from whole to pieces, therefore no spin doctor nor lying expert can convince CRITICAL THINKING people that the WTC was demolished by gravity energy.
Everyone is familiar with shoe TYING, so the DISPROOF cannot be ignored, while only people educated in engineering such as myself are familiar with material MILLING, so the DISPROOF is ignored.
If you go to an engineering school or concrete manufacturer and watch them fail concrete an INTACT piece of concrete, you will notice that it breaks into sand sized particles, and in order to turn it into a 50 micron fine powder you would have to MILL those particles.
Even if you drop concrete from 30,000 jet crusing altitude, it will still fail into sand size particles, just like you cannot make flour from wheat kernels by dropping them off a tall building!
Even if you put more tha X pounds of weight on a cubic inch of concrete that has a compression strength X pounds per inch, it will still fail into sand size particles, just like you cannot make flour from wheat kernels by setting them under a heavy rock!
The reason you cannot make fine powders simply by dropping material, is that the material's collision with the ground results in the small particles recoiling upward instead of them being breaking into smaller and smaller pieces, no matter how much FORCE they hit the ground with.
The reason you cannot make fine powders simply by setting weight on material, is that the surfaces are not perfectly even, so small particles lay in the hills and the valleys between the surfaces, therefore they CANNOT be broken into smaller particles because NO FORCE is being applied to them, no matter how much FORCE is being applied to surfaces.
MILLING can be done by the scraping of abrasives which chew off one fine powder particle at a time, or done by the crushing of surfaces that are SMOOTHER than the desired fine powder particle size.
Since the environment in the demolished WTC towers was not like a MILL, and MILLING always takes more than 15 seconds to generate an appreciable amount of fine powder, WE KNOW FOR A FACT THAT THE 50 MICRON 45% SILICON FINE POWDER THAT IS GIVING THE FIRST RESPONDERS SILICOSIS LUNG DISEASE HAD TO BE CREATED BY EXPLOSIVES, BECAUSE THERE IS NO OTHER WAY FOR THAT POWDER TO BE CREATED IN THE TIME AND ENVIRONMENT OF A DEMOLISHING WTC TOWER.
I will give my house, car, money, clothes, and every worldly possession to the first person lying expert or otherwise who can turn an intact piece of concrete or glass into a 50 micron fine powder in less than 15 seconds without explosives, even though they would not need my money, because they will have won a Nobel prize and would have a zillion dollar patent for making milling obsolete!
So if you choose to believe the official LIE, and ignore the TRUTH that the WTC towers were brought down with explosives, by IGNORING the IRRFUTABLE evidence that the critical thinker has given you, it simply means your emotions overrule your logic, and your psyche cannot handle the ramifications of this IRRFUTABLE evidence, so you close your eyes and keep believing that it was not an inside job when the evidence OBVIOUSLY says otherwise to CRITICAL THINKING people like Columbo.
Critical Thinker, is obviously LYING when he claims:
Because its obvious he doesn't know what he is talking about.
IF (BIG IF) the towers were brought down by explosives,
THEN, the explosives would have had to be used to CUT CORE COLUMNS
Cutting Core columns with explosives WOULD NOT generate much dust either, since again, all you would be doing would be cutting the columns on one floor and the core columns were NOT encased in concrete.
There is NO LOGICAL reason to use explosives to blow up the concrete on the lightweight FLOORS, which is where the majority of the concrete in the building is located.
Previously it has been shown by Neu that Explosives, are in fact, a POOR method of creating this dust.
Your supposed DISPROOF fails on multiple levels.
Because its obvious he doesn't know what he is talking about.
IF (BIG IF) the towers were brought down by explosives,
THEN, the explosives would have had to be used to CUT CORE COLUMNS
Cutting Core columns with explosives WOULD NOT generate much dust either, since again, all you would be doing would be cutting the columns on one floor and the core columns were NOT encased in concrete.
There is NO LOGICAL reason to use explosives to blow up the concrete on the lightweight FLOORS, which is where the majority of the concrete in the building is located.
Previously it has been shown by Neu that Explosives, are in fact, a POOR method of creating this dust.
Your supposed DISPROOF fails on multiple levels.
I will give my house, car, money, clothes, and every worldly possession to the first person lying expert or otherwise who can turn an intact piece of concrete or glass into a 50 micron fine powder in less than 15 seconds without explosives
Lets see, we know the forces unleashed when those towers fell was in the scale of a small nuclear device, but since I can't use explosives, then in order to win your double-wide, your run out Civic, the few bucks and rags you own, ALL I need is a 1,400 ft tower made out of steel and concrete that I can destroy.
I'd say that's a fairly safe bet.
Of course it proves MORE about the person making the bet then the subject of the bet.
Arthur
ROTFLMAO
A "troofer" asking David to show a little more Scientific Acumen.
Please STOP.
That just ruined another of my IRONY METERS.
They just can't take that kind of SEVERE OVERLOAD.
Arthur
Also in a normal CD the explosives are only the catalyst and gravity the engine.
Einsteen, you know it, I know it, now try to convince your fellow CTs of this fact. A good number of them are under the assumption that a gravity driven collapse cannot produce the fine concrete dust exhibited in the WTC collapses.
Incidentally, I don't think even the NIST supports your idea that the "frame members" "were simply pushed to the outside and fell over.", nor that the floors bypassed the perimeter and core columns first. Their theory is a kind of upper block piledriver wish crushes the bottom structure floor by floor.
Crushes the bottom FLOORS, but NOT the columns.
They DO support this idea via their analysis of the failed seats being primarily downward below the point of impact and their description of the failure mode (after initiation) as "pancaking".
Arthur
QUOTE
only people educated in engineering such as myself
Because its obvious he doesn't know what he is talking about.
IF (BIG IF) the towers were brought down by explosives,
THEN, the explosives would have had to be used to CUT CORE COLUMNS
Cutting Core columns with explosives WOULD NOT generate much dust either, since again, all you would be doing would be cutting the columns on one floor and the core columns were NOT encased in concrete.
There is NO LOGICAL reason to use explosives to blow up the concrete on the lightweight FLOORS, which is where the majority of the concrete in the building is located.
Previously it has been shown by Neu that Explosives, are in fact, a POOR method of creating this dust.
Your supposed DISPROOF fails on multiple levels.
QUOTE (->
| QUOTE |
| only people educated in engineering such as myself |
Because its obvious he doesn't know what he is talking about.
IF (BIG IF) the towers were brought down by explosives,
THEN, the explosives would have had to be used to CUT CORE COLUMNS
Cutting Core columns with explosives WOULD NOT generate much dust either, since again, all you would be doing would be cutting the columns on one floor and the core columns were NOT encased in concrete.
There is NO LOGICAL reason to use explosives to blow up the concrete on the lightweight FLOORS, which is where the majority of the concrete in the building is located.
Previously it has been shown by Neu that Explosives, are in fact, a POOR method of creating this dust.
Your supposed DISPROOF fails on multiple levels.
I will give my house, car, money, clothes, and every worldly possession to the first person lying expert or otherwise who can turn an intact piece of concrete or glass into a 50 micron fine powder in less than 15 seconds without explosives
Lets see, we know the forces unleashed when those towers fell was in the scale of a small nuclear device, but since I can't use explosives, then in order to win your double-wide, your run out Civic, the few bucks and rags you own, ALL I need is a 1,400 ft tower made out of steel and concrete that I can destroy.
I'd say that's a fairly safe bet.
Of course it proves MORE about the person making the bet then the subject of the bet.
Arthur
Criticalthinker:
I will give my house, car, money, clothes, and every worldly possession to the first expert or otherwise who can look at the photographs of the Streets of Manhattan after 9/11 (as shown on the 911-Research site ), and tell me all that dust is "50 micron 45% silicon fine powder.
I will give my house, car, money, clothes, and every worldly possession to the first expert or otherwise who can look at the photographs of the Streets of Manhattan after 9/11 (as shown on the 911-Research site ), and tell me all that dust is "50 micron 45% silicon fine powder.
Careful Neu,
I (and every Troofer) can TELL you that.
Troofers are REAL GOOD at DECLARING what is TRUTH. What must be vs what must not be, what is versus what isn't.
Arthur
I (and every Troofer) can TELL you that.
Troofers are REAL GOOD at DECLARING what is TRUTH. What must be vs what must not be, what is versus what isn't.
Arthur
QUOTE (criticalthinker+Apr 30 2007, 07:16 PM)
... no matter how much FORCE they hit the ground with.
But as an engineer, you believe in the results of experiments.
Take 500,000 tonnes of diverse, crushed materials, including 96,000 tonnes of structural steel and 48,000 tonnes of concrete, all well mixed, and drop at 50 m/s (hat's 110 mph for engineers) onto six layers of concrete basement floor, the bottom one on bedrock. Observe.
Oh wait!
This experiment has already been done. 
Twice.
But as an engineer, you believe in the results of experiments.
Take 500,000 tonnes of diverse, crushed materials, including 96,000 tonnes of structural steel and 48,000 tonnes of concrete, all well mixed, and drop at 50 m/s (hat's 110 mph for engineers) onto six layers of concrete basement floor, the bottom one on bedrock. Observe.
Oh wait!
This experiment has already been done. Twice.
criticalthinker
If you hit a piece of concrete with a hammer a certain portion of the scattering fragments will always be dust flying away from the point of impact. Some of that dust will be 50 micron or below. Everytime you hit the concrete you will produce a little dust= coarser particles. When I ran a rock drill we were covered in the finest talcum powder sized dust, the rest fell out of suspension with the air before it floated far enough to reach us at the back. Any impact on concrete will produce a range of sizes for the particle, it ALWAYS includes the smaller sizes. That is just fact. When the concrete in question is measured in hundreds of TONS, you will end up with at least several tons of ultrafine dust, even if it is but a small fraction of the total mass. So this statement...
...is silly and just proves you don't know anything about which you are speaking.
Oh, and there is an immense difference in failure modes between a compression failure and a smack with a big hammer(or rock drill). The lack of dust in a compression failure says nothing about there being no dust in an impact event. In fact, a hammer or ball mill creates dust size particles because it is impact, not pressure, that these devices use. The WTC towers can be seen as huge, inefficient(but effective) ball mills for the production of some tons of <50 micron dust, the movement of air seperated it from the other rubble so it floated further and got smaller the further away it was.
You'll have to wait for that Nobel Prize, you have proven nothing here but your ignorance.
Grumpy
If you hit a piece of concrete with a hammer a certain portion of the scattering fragments will always be dust flying away from the point of impact. Some of that dust will be 50 micron or below. Everytime you hit the concrete you will produce a little dust= coarser particles. When I ran a rock drill we were covered in the finest talcum powder sized dust, the rest fell out of suspension with the air before it floated far enough to reach us at the back. Any impact on concrete will produce a range of sizes for the particle, it ALWAYS includes the smaller sizes. That is just fact. When the concrete in question is measured in hundreds of TONS, you will end up with at least several tons of ultrafine dust, even if it is but a small fraction of the total mass. So this statement...
QUOTE
The 50 micron 45% silicon fine powder in the above link DISPROVES that the WTC was demolished by gravity energy, because there is no other way than explosive energy to created such a fine silicon powder from intact concrete and glass in the less than 15 seconds
...is silly and just proves you don't know anything about which you are speaking.
Oh, and there is an immense difference in failure modes between a compression failure and a smack with a big hammer(or rock drill). The lack of dust in a compression failure says nothing about there being no dust in an impact event. In fact, a hammer or ball mill creates dust size particles because it is impact, not pressure, that these devices use. The WTC towers can be seen as huge, inefficient(but effective) ball mills for the production of some tons of <50 micron dust, the movement of air seperated it from the other rubble so it floated further and got smaller the further away it was.
You'll have to wait for that Nobel Prize, you have proven nothing here but your ignorance.
Grumpy
QUOTE (adoucette+Apr 30 2007, 08:14 PM)
I (and every Troofer) can TELL you that.
GLENDOWER
I can call spirits from the vasty deep.
HOTSPUR
Why, so can I, or so can any man;
But will they come when you call for them?
GLENDOWER
I can call spirits from the vasty deep.
HOTSPUR
Why, so can I, or so can any man;
But will they come when you call for them?
QUOTE (David B. Benson+Apr 30 2007, 08:22 PM)
But as an engineer, you believe in the results of experiments.
Take 500,000 tonnes of diverse, crushed materials, including 96,000 tonnes of structural steel and 48,000 tonnes of concrete, all well mixed, and drop at 50 m/s (hat's 110 mph for engineers) onto six layers of concrete basement floor, the bottom one on bedrock. Observe.
Oh wait! This experiment has already been done. Twice.
You truly are the king of logical fallacies and circular reasoning!
There were no explosives, therefore all characteristics of the WTC collapse were caused by gravity alone, therefore there were no explosives. QED.
Solid.
Take 500,000 tonnes of diverse, crushed materials, including 96,000 tonnes of structural steel and 48,000 tonnes of concrete, all well mixed, and drop at 50 m/s (hat's 110 mph for engineers) onto six layers of concrete basement floor, the bottom one on bedrock. Observe.
Oh wait!
This experiment has already been done. Twice. You truly are the king of logical fallacies and circular reasoning!
There were no explosives, therefore all characteristics of the WTC collapse were caused by gravity alone, therefore there were no explosives. QED.
Solid.
QUOTE (lozenge124+Apr 30 2007, 09:01 PM)
Solid.
Read again, carefully this time, the initial conditions given for the experiment.
To be blunt about it, note that nothing is stated regarding the means by which the initial conditions are to be generated.
You do your experimental set-up your way and I'll do mine my way.
Read again, carefully this time, the initial conditions given for the experiment.
To be blunt about it, note that nothing is stated regarding the means by which the initial conditions are to be generated.
You do your experimental set-up your way and I'll do mine my way.
QUOTE (lozenge124+Apr 30 2007, 04:01 PM)
There were no explosives, therefore all characteristics of the WTC collapse were caused by gravity alone, therefore there were no explosives. QED.
Nope,
Go to any CD site.
Watch the videos of the CDs.
The Dust is NOT created when the explosives go off (there is even a site that shows some views taken from INSIDE the building and its clear that the explosives create CHUNKS but not much dust).
What is clear is that the massive amounts of dust are created in the last seconds of the collapse as the accelerating mass reaches the ground.
By GRAVITY.
Not by Explosives.
Which, in a CD, are shaped charges whose energy is FOCUSED to CUT STEEL, not break up concrete.
Which explosives are apparently not that good at.
Arthur
Nope,
Go to any CD site.
Watch the videos of the CDs.
The Dust is NOT created when the explosives go off (there is even a site that shows some views taken from INSIDE the building and its clear that the explosives create CHUNKS but not much dust).
What is clear is that the massive amounts of dust are created in the last seconds of the collapse as the accelerating mass reaches the ground.
By GRAVITY.
Not by Explosives.
Which, in a CD, are shaped charges whose energy is FOCUSED to CUT STEEL, not break up concrete.
Which explosives are apparently not that good at.
Arthur
QUOTE (David B. Benson+Apr 30 2007, 09:05 PM)
Read again, carefully this time, the initial conditions given for the experiment.
To be blunt about it, note that nothing is stated regarding the means by which the initial conditions are to be generated.
You do your experimental set-up your way and I'll do mine my way.
Your patronizing attitude might be more warranted if you displayed a little more scientific acumen, my friend.
To be blunt about it, note that nothing is stated regarding the means by which the initial conditions are to be generated.
You do your experimental set-up your way and I'll do mine my way.
Your patronizing attitude might be more warranted if you displayed a little more scientific acumen, my friend.
ROTFLMAO
A "troofer" asking David to show a little more Scientific Acumen.
Please STOP.
That just ruined another of my IRONY METERS.
They just can't take that kind of SEVERE OVERLOAD.
Arthur
QUOTE (lozenge124+Apr 30 2007, 09:35 PM)
a little more scientific acumen ...
All my life (well, ever since sixth grade) I've been trying to display a little more scientific acumen.
Guess I'll have to keep trying...
Anyway, here are two links to slightly different underground damage assessment maps.
Thanks to Arthur for relocating the second one.
TNYT Underground Damage
I quote from the place where I found this link: "In all there were 7 stories [down from the plaza level] of sublevels within the area west of the subway of which the lowest sublevel 6 was two stories high. The area east of the subway was 2 sublevels as depicted in the diagram."
Gif walk down the sublevels
All my life (well, ever since sixth grade) I've been trying to display a little more scientific acumen.
Guess I'll have to keep trying...
Anyway, here are two links to slightly different underground damage assessment maps.
Thanks to Arthur for relocating the second one.
TNYT Underground Damage
I quote from the place where I found this link: "In all there were 7 stories [down from the plaza level] of sublevels within the area west of the subway of which the lowest sublevel 6 was two stories high. The area east of the subway was 2 sublevels as depicted in the diagram."
Gif walk down the sublevels
QUOTE (David B. Benson+Apr 29 2007, 02:17 PM)
The assumptions might also be called simplifying hypotheses. B & V have four, sharing the first three with Greening. I am prepared to defend all four, especially after demonstrating that the B & V crush-down equation gives answers closely agreeing with actual data.
Metamars only objection was, essentially, the constitutive character of the resulting equations. I suppose he then also objects to Hook's Law since it is also constitutive in character.
But bring forth your objections and I'll deal with each one.
So the unvalidated assumptions might also be called unvalidated simplifying
hypotheses. I am doubtful that you can defend them, but you deserve the opportunity
to try if you are so moved. If we set this aside for a moment and suppose that the
assumptions are valid, I have another issue. Let me ask it of you this way, if you were
given a set of data blindly, not knowing whether the data applied to a gravity driven
collapse or a controlled demolition, do you believe on the basis of the Greening/BV
model that you could choose accurately between the two possibilities? If you say yes,
then we probably have an unresolvable disagreement between us. You have selected
time of collapse as the only observable you are interested in. You are satisfied if you
find a fit to that. Controlled demolition can as adequately fit this piece of data.
Therefore, removing personal biases and emotions, on this basis there is no reason to
select one hypothesis over the other.
Metamars only objection was, essentially, the constitutive character of the resulting equations. I suppose he then also objects to Hook's Law since it is also constitutive in character.
But bring forth your objections and I'll deal with each one.
So the unvalidated assumptions might also be called unvalidated simplifying
hypotheses. I am doubtful that you can defend them, but you deserve the opportunity
to try if you are so moved. If we set this aside for a moment and suppose that the
assumptions are valid, I have another issue. Let me ask it of you this way, if you were
given a set of data blindly, not knowing whether the data applied to a gravity driven
collapse or a controlled demolition, do you believe on the basis of the Greening/BV
model that you could choose accurately between the two possibilities? If you say yes,
then we probably have an unresolvable disagreement between us. You have selected
time of collapse as the only observable you are interested in. You are satisfied if you
find a fit to that. Controlled demolition can as adequately fit this piece of data.
Therefore, removing personal biases and emotions, on this basis there is no reason to
select one hypothesis over the other.
Dust maker.... Gypsum board. Lots of it. How much you ask?
Don't know, says I. LOTS. Acres.
What does it take to make gypsum board into powder? Lots of it? Don't know says I, but not much...
Did anyone give that little detail some thought? and the fact that it (the dust) would be mixed in with everything?...
Oh, just for arguments sake:
The Bestwall chemists continued to
improve the core formulation to increase
the performance of the board.
This led to additional patents being
granted to Michael Croce and Clarence
G. Shuttleworth in June of 1954. The
patent was based on original applications
made in July of 1951 and represented
the primary development incorporating
glass fibers in gypsum. It had
been found from experiments that
while several other fibers could perform
satisfactorily to attain fire
resistance products, all but one
anybody notice the use of GLASS FIBERS in the gypsum?
Just an errant thought, more fuel to the fire.
Don't know, says I. LOTS. Acres.
What does it take to make gypsum board into powder? Lots of it? Don't know says I, but not much...
Did anyone give that little detail some thought? and the fact that it (the dust) would be mixed in with everything?...
Oh, just for arguments sake:
The Bestwall chemists continued to
improve the core formulation to increase
the performance of the board.
This led to additional patents being
granted to Michael Croce and Clarence
G. Shuttleworth in June of 1954. The
patent was based on original applications
made in July of 1951 and represented
the primary development incorporating
glass fibers in gypsum. It had
been found from experiments that
while several other fibers could perform
satisfactorily to attain fire
resistance products, all but one
anybody notice the use of GLASS FIBERS in the gypsum?
Just an errant thought, more fuel to the fire.
For the doubters of gravitational collapse as a mechanism for the pulverization of concrete, here is an example of such from the collapse of the towers.
Here's an interesting article on concrete decay.
Clients in denial as concrete decay stalks Dubai buildings:
http://www.nceplus.co.uk/news/news_article...ingFrom=RSSFeed
The article doesn't get into the specifics of what areas of the buildings are at risk, but statements like "Concrete buildings in Dubai are at risk of collapse" emphasize the seriousness of the problem. It makes you wonder about the condition of the concrete in the Trade Center buildings at the time of their demise.
Clients in denial as concrete decay stalks Dubai buildings:
http://www.nceplus.co.uk/news/news_article...ingFrom=RSSFeed
The article doesn't get into the specifics of what areas of the buildings are at risk, but statements like "Concrete buildings in Dubai are at risk of collapse" emphasize the seriousness of the problem. It makes you wonder about the condition of the concrete in the Trade Center buildings at the time of their demise.
Could the hydrogen sulfide produced in human flatulence be an indoor source of sulfur related concrete decay?
Would the sulfur dioxide emissions from burning high sulfur fuels over the past decades have contributed to the sulfur exposure of indoor structural concrete?
Would the sulfur dioxide emissions from burning high sulfur fuels over the past decades have contributed to the sulfur exposure of indoor structural concrete?
QUOTE (David B. Benson+Apr 28 2007, 12:04 AM)
Sonic boom calculation --- A particle of air just at the boundary between the core and the long trussed floor has to travel 18.3 meters to reach a window, assuming a straight line. (I assume that the air in the core escaped downwards through the voids in the core.) So to reach a window in 0.075 seconds requires an average speed of 244 m/s. The speed of sound at sea level is 344 m/s. Assuming a constant acceleration for the particle of air, ignoring compressibility and shock fronts, its maximum speed, at the window, would be 488 m/s, definitely supersonic.
So by this rough calculation, sonic booms are a possibility.
I'm not sure which boom booms one is referring to but I get different numbers.
The maximum speed is only reached at the bottom, but let's assume the velocity is 50 m/s in the beginning (at the top) then it takes indeed 0.075s to compact a story.
The total volume of uncompressed air (ignoring something is in the building) per storey is 64x64x3.7 m^3, the total area from where the air can leave is 64x4x3.7 m^2, this gives a maximum velocity of 64/(4 x 0.075) which gives 213 m/s << 1 mach
Of course uniformity is assumed, if we now lower it with 10% (building is 90% air) and also don't take the 50m/s but for example 25m/s then supersonic booms cannot be explained in the beginning... and also not at the end. Uniformity is assumed but that's a matter of modeling, in the same way as 1d uniform E1/m_f models are used.
No supersonic booms.
So by this rough calculation, sonic booms are a possibility.
I'm not sure which boom booms one is referring to but I get different numbers.
The maximum speed is only reached at the bottom, but let's assume the velocity is 50 m/s in the beginning (at the top) then it takes indeed 0.075s to compact a story.
The total volume of uncompressed air (ignoring something is in the building) per storey is 64x64x3.7 m^3, the total area from where the air can leave is 64x4x3.7 m^2, this gives a maximum velocity of 64/(4 x 0.075) which gives 213 m/s << 1 mach
Of course uniformity is assumed, if we now lower it with 10% (building is 90% air) and also don't take the 50m/s but for example 25m/s then supersonic booms cannot be explained in the beginning... and also not at the end. Uniformity is assumed but that's a matter of modeling, in the same way as 1d uniform E1/m_f models are used.
No supersonic booms.
QUOTE (adoucette+Apr 28 2007, 03:02 AM)
Get used to disappointment.
Gravity doesn't scale.
Arthur
Gravity doesn't scale but you could put a model in a centrifuge... would be easier than accelerate it in a big elevator...
Gravity doesn't scale.
Arthur
Gravity doesn't scale but you could put a model in a centrifuge... would be easier than accelerate it in a big elevator...
QUOTE (Capracus+May 1 2007, 11:04 AM)
Could the hydrogen sulfide produced in human flatulence be an indoor source of sulfur related concrete decay?
Would the sulfur dioxide emissions from burning high sulfur fuels over the past decades have contributed to the sulfur exposure of indoor structural concrete?
You forgot bacteria, in high sulfur diesel fuels stored in the buildings for decades, releasing SO2.
Do not leave out the little guys.
Hydrogen sulfide is produce by bacterial breaking down organics like skin flake in the carpets as well humans give off a lot of them.
Would the sulfur dioxide emissions from burning high sulfur fuels over the past decades have contributed to the sulfur exposure of indoor structural concrete?
You forgot bacteria, in high sulfur diesel fuels stored in the buildings for decades, releasing SO2.
Do not leave out the little guys.
Hydrogen sulfide is produce by bacterial breaking down organics like skin flake in the carpets as well humans give off a lot of them.
QUOTE (David B. Benson+Apr 30 2007, 10:03 PM)
All my life (well, ever since sixth grade) I've been trying to display a little more scientific acumen.
Guess I'll have to keep trying...
Anyway, here are two links to slightly different underground damage assessment maps.
Thanks to Arthur for relocating the second one.
TNYT Underground Damage
I quote from the place where I found this link: "In all there were 7 stories [down from the plaza level] of sublevels within the area west of the subway of which the lowest sublevel 6 was two stories high. The area east of the subway was 2 sublevels as depicted in the diagram."
Gif walk down the sublevels
From the TNYT link David posted:
North Tower
1. Television antenna begins to fall, suggesting failures of central columns.
2. The portion of the building above the impact fell as a unit, pushing a cushion of air down.
3. The air fed fires in the impact area, creating the illusion of an explosion.
================
Aren't you guys saying the television tower falling was just an illusion caused by the upper portion tilting?
Pushing a cushion of air? hmmmm.....
TNYT is in error? Have any of you contacted them so they can correct this misinformation?
Guess I'll have to keep trying...
Anyway, here are two links to slightly different underground damage assessment maps.
Thanks to Arthur for relocating the second one.
TNYT Underground Damage
I quote from the place where I found this link: "In all there were 7 stories [down from the plaza level] of sublevels within the area west of the subway of which the lowest sublevel 6 was two stories high. The area east of the subway was 2 sublevels as depicted in the diagram."
Gif walk down the sublevels
From the TNYT link David posted:
North Tower
1. Television antenna begins to fall, suggesting failures of central columns.
2. The portion of the building above the impact fell as a unit, pushing a cushion of air down.
3. The air fed fires in the impact area, creating the illusion of an explosion.
================
Aren't you guys saying the television tower falling was just an illusion caused by the upper portion tilting?
Pushing a cushion of air? hmmmm.....
TNYT is in error? Have any of you contacted them so they can correct this misinformation?
I also thought that antenna dropped first but at that time I didn't know that wtc1 toppled and after that I forgot about it and removed all stuff I had about it.
But in the recent interview with the NIST communicator (there is a mp3 available , Shure@LCF made it) he said that the core failed first, hell...I then think how do you want to make that consistent with a pancake/progressive collapse in which only floors are detached from a core that is still intact after the collapse?
But in the recent interview with the NIST communicator (there is a mp3 available , Shure@LCF made it) he said that the core failed first, hell...I then think how do you want to make that consistent with a pancake/progressive collapse in which only floors are detached from a core that is still intact after the collapse?
QUOTE (forthetrees+May 1 2007, 01:45 PM)
From the TNYT link David posted:
North Tower
1. Television antenna begins to fall, suggesting failures of central columns.
2. The portion of the building above the impact fell as a unit, pushing a cushion of air down.
3. The air fed fires in the impact area, creating the illusion of an explosion.
================
Aren't you guys saying the television tower falling was just an illusion caused by the upper portion tilting?
Pushing a cushion of air? hmmmm.....
TNYT is in error? Have any of you contacted them so they can correct this misinformation?
Its pretty much a given, if the subject is SCIENCE then the TNYT is probably in error.
IIRC even FEMA believed that the antenna fell into the building, but it was NIST with their much more extensive video & picture database who realized that the apparent downward movement was caused by the tilting away from those North face views.
Arthur
North Tower
1. Television antenna begins to fall, suggesting failures of central columns.
2. The portion of the building above the impact fell as a unit, pushing a cushion of air down.
3. The air fed fires in the impact area, creating the illusion of an explosion.
================
Aren't you guys saying the television tower falling was just an illusion caused by the upper portion tilting?
Pushing a cushion of air? hmmmm.....
TNYT is in error? Have any of you contacted them so they can correct this misinformation?
Its pretty much a given, if the subject is SCIENCE then the TNYT is probably in error.
IIRC even FEMA believed that the antenna fell into the building, but it was NIST with their much more extensive video & picture database who realized that the apparent downward movement was caused by the tilting away from those North face views.
Arthur
QUOTE (eigenvalue+May 1 2007, 12:56 AM)
if you were given a set of data blindly, not knowing whether the data applied to a gravity driven collapse or a controlled demolition, do you believe on the basis of the Greening/BV model that you could choose accurately between the two possibilities?
Yes. Top-down progressive collapse is crush-down, CD is crush-up (at worst).
NEU-FONZE measured the drop of each tower for the first few seconds. This is enough data to distinguish crush-down from crush-up and especially from the nearly free-fall condition of a properly done CD. This is more data than simply the single total time to completely collapse.
Yes. Top-down progressive collapse is crush-down, CD is crush-up (at worst).
NEU-FONZE measured the drop of each tower for the first few seconds. This is enough data to distinguish crush-down from crush-up and especially from the nearly free-fall condition of a properly done CD. This is more data than simply the single total time to completely collapse.
QUOTE (Palpatane+May 1 2007, 07:06 PM)
http://429truth.com/
Enjoy.
I knew it was a conspiracy from the start.
It's comforting to see that others feel the same way.
I'm thinking of making a documentary to expose the truth of the incident and calling it Loose Interchange.
Enjoy.
I knew it was a conspiracy from the start.
It's comforting to see that others feel the same way.
I'm thinking of making a documentary to expose the truth of the incident and calling it Loose Interchange.
QUOTE (einsteen+May 1 2007, 11:30 AM)
I'm not sure which boom booms one is referring to but I get different numbers.
...
No supersonic booms.
Your setup is wrong.
But I agree that sonic booms are improbable. (1) Do not seem to be on any audio track for the estimated time of maximum speed. (2) Would require some rather unlikely tunneling effect.
Still, maybe there were a few...
...
No supersonic booms.
Your setup is wrong.
But I agree that sonic booms are improbable. (1) Do not seem to be on any audio track for the estimated time of maximum speed. (2) Would require some rather unlikely tunneling effect.
Still, maybe there were a few...
QUOTE (Capracus+May 1 2007, 10:00 PM)
I knew it was a conspiracy from the start.
It's comforting to see that others feel the same way.
I'm thinking of making a documentary to expose the truth of the incident and calling it Loose Interchange.
typical 'de'bunkers.
the windsor tower cannot be compared.
the empire state building cannot be compared.
heck, even the WTC fire in the seventies is disallowed.
but a TANKER FULL of GASOLINE burning MUCH hotter than the wtc fires break a bridge, and you 'scientists' are all over it.
it's not washing. more and more REAL scientists and engineers and pilots are coming out to crush up/crush down the LIE.
It's comforting to see that others feel the same way.
I'm thinking of making a documentary to expose the truth of the incident and calling it Loose Interchange.
typical 'de'bunkers.
the windsor tower cannot be compared.
the empire state building cannot be compared.
heck, even the WTC fire in the seventies is disallowed.
but a TANKER FULL of GASOLINE burning MUCH hotter than the wtc fires break a bridge, and you 'scientists' are all over it.
it's not washing. more and more REAL scientists and engineers and pilots are coming out to crush up/crush down the LIE.
QUOTE (newton+May 1 2007, 10:49 PM)
typical 'de'bunkers.
the windsor tower cannot be compared.
the empire state building cannot be compared.
heck, even the WTC fire in the seventies is disallowed.
but a TANKER FULL of GASOLINE burning MUCH hotter than the wtc fires break a bridge, and you 'scientists' are all over it.
it's not washing. more and more REAL scientists and engineers and pilots are coming out to crush up/crush down the LIE.
Come on newton, get on board, the 4/29 truth movement needs members with vivid imaginations like yours.
I could use your input on my documentary Loose Interchange, I'm not sure if I can make it incredible enough to sell to the majority of truthers.
the windsor tower cannot be compared.
the empire state building cannot be compared.
heck, even the WTC fire in the seventies is disallowed.
but a TANKER FULL of GASOLINE burning MUCH hotter than the wtc fires break a bridge, and you 'scientists' are all over it.
it's not washing. more and more REAL scientists and engineers and pilots are coming out to crush up/crush down the LIE.
Come on newton, get on board, the 4/29 truth movement needs members with vivid imaginations like yours.
I could use your input on my documentary Loose Interchange, I'm not sure if I can make it incredible enough to sell to the majority of truthers.
QUOTE (newton+May 1 2007, 05:49 PM)
more and more REAL scientists and engineers and pilots are coming out to crush up/crush down the LIE.
Where have they published something to support your contentions?
Arthur
Where have they published something to support your contentions?
Arthur
It is interesting that the claim has already been made that the Oakland bridge collapsed because "the bolts holding the structure together melted".
See Associated Press Article dated April 29, 2007, by Marcus Wohlsen who quotes Will Kempton, the California Department of Transportation Director. Would this guy be an engineer?
See Associated Press Article dated April 29, 2007, by Marcus Wohlsen who quotes Will Kempton, the California Department of Transportation Director. Would this guy be an engineer?
publish, smublish. where's the impeachment? it's warranted, but not happening (loudly). where's the media reports of the impeachment that's in the works?
sorry, but EVERYTHING is under big brother's thumb, and yes a great deal of people are 'IN ON IT'.
look at this building collapse....
youtube thrilla in manilla
that looks like a mostly concrete building, ie, more likely to fracture than the steel frame of the WTC.
none the less, it is a much better demonstration of how a building reacts to having it's legs pulled out than your INFERNO under a bridge analogy.
sorry, but EVERYTHING is under big brother's thumb, and yes a great deal of people are 'IN ON IT'.
look at this building collapse....
youtube thrilla in manilla
that looks like a mostly concrete building, ie, more likely to fracture than the steel frame of the WTC.
none the less, it is a much better demonstration of how a building reacts to having it's legs pulled out than your INFERNO under a bridge analogy.
One possible way for structural steel bolts to appear to "melt" below the melting point of steel is through zinc embrittlement. This would apply if the Oakland bridge had GALVANIZED STEEL bolts. See ASTM A325 or A490 Bolt Specification available from www.boltcouncil.org
QUOTE (David B. Benson+May 1 2007, 01:47 PM)
Yes. Top-down progressive collapse is crush-down, CD is crush-up (at worst).
Your answer is incorrect. Greening applied his model to bottom-up WTC 7 "collapse"
some many posts ago, so he would have it apply to a crush-up case as well. Hence
there is no way on the basis of the model to distinguish between a gravity driven
progressive collapse and controlled demolition. In this regard, the model is no better
than a flip of the coin. In the WTC 1 and 2 cases, crush-down is a conceptual element of
the model that cannot be documented. Further, the occurrence of crush-down
requires us to invoke those unvalidated assumptions, so it is possible (IMO likely) the
model does not even apply. Demolition cannot be ruled out on the account of any of
the observables. So, again, there is nothing in the model to help us decide. The model
by itself is of no value. If you wish to believe otherwise, so be it.
Your answer is incorrect. Greening applied his model to bottom-up WTC 7 "collapse"
some many posts ago, so he would have it apply to a crush-up case as well. Hence
there is no way on the basis of the model to distinguish between a gravity driven
progressive collapse and controlled demolition. In this regard, the model is no better
than a flip of the coin. In the WTC 1 and 2 cases, crush-down is a conceptual element of
the model that cannot be documented. Further, the occurrence of crush-down
requires us to invoke those unvalidated assumptions, so it is possible (IMO likely) the
model does not even apply. Demolition cannot be ruled out on the account of any of
the observables. So, again, there is nothing in the model to help us decide. The model
by itself is of no value. If you wish to believe otherwise, so be it.
QUOTE (eigenvalue+May 2 2007, 01:29 AM)
The model by itself is of no value.
Wrong again. A well done CD will provide drops giving an acceleration close to g. Otherwise, one needs enough data to distinguish crush-down from crush-up, assuming one is not allowed to actual see which of the two is occurring.
Roughly, crush-down involves conservation of momentum while crush-up does not. There are further distinguishing details.
Anyway, the simplest way to see that the collapse of the towers was not a well done CD is to determine the value for a is the equation
d = (1/2)at^2
The best fit to NEU-FONZE's measurements is
WTC 1: a = 0.66g
WTC 2: a = 0.75g
both of which show that the towers were offering some resistance. The fit to the crush-down equation is much better than to the simple parabola.
Wrong again. A well done CD will provide drops giving an acceleration close to g. Otherwise, one needs enough data to distinguish crush-down from crush-up, assuming one is not allowed to actual see which of the two is occurring.
Roughly, crush-down involves conservation of momentum while crush-up does not. There are further distinguishing details.
Anyway, the simplest way to see that the collapse of the towers was not a well done CD is to determine the value for a is the equation
d = (1/2)at^2
The best fit to NEU-FONZE's measurements is
WTC 1: a = 0.66g
WTC 2: a = 0.75g
both of which show that the towers were offering some resistance. The fit to the crush-down equation is much better than to the simple parabola.
another demonstration of what structures that are designed to stand up act like when you pull the legs out....
youtube: tower gets downed by psycho machine operator
youtube: tower gets downed by psycho machine operator
QUOTE (newton+May 1 2007, 09:02 PM)
another demonstration of what structures that are designed to stand up act like when you pull the legs out....
youtube: tower gets downed by psycho machine operator
Except its a six legged structure and the operator takes out THREE legs on one side (you can see that two are already cut right at the start of the video) so of course this otherwise rigid structure topples towards the side that has been removed.
Arthur
youtube: tower gets downed by psycho machine operator
Except its a six legged structure and the operator takes out THREE legs on one side (you can see that two are already cut right at the start of the video) so of course this otherwise rigid structure topples towards the side that has been removed.
Arthur
QUOTE (newton+)
smublish
That's the CT'er equivalent I guess.
What's that ya got newton?
NOTHING
NADA
ZIP
ZILCH
Arthur
That's the CT'er equivalent I guess.
What's that ya got newton?
NOTHING
NADA
ZIP
ZILCH
Arthur
QUOTE (eigenvalue+May 1 2007, 08:29 PM)
Demolition cannot be ruled out on the account of any of the observables.
Nope,
The collapse clearly begins in BOTH towers on the fire and impact floors.
The collapse clearly begins BEFORE there is a large expulsion of flame and smoke.
There was no way to predict exactly which floors the terrorists would fly the planes into, thus making pre-planting of the explosives on the impact floors highly improbable.
And as highly improbable as that would be, there is no way that explosives could have survived on those floors an hour past the impacts and ensuing fires.
Finally, the visual evidence of the slow pulling in of the perimeter columns clearly shows that it was the fire that was destroying the only reserve capacity the buildings had left, not explosives.
Arthur
Nope,
The collapse clearly begins in BOTH towers on the fire and impact floors.
The collapse clearly begins BEFORE there is a large expulsion of flame and smoke.
There was no way to predict exactly which floors the terrorists would fly the planes into, thus making pre-planting of the explosives on the impact floors highly improbable.
And as highly improbable as that would be, there is no way that explosives could have survived on those floors an hour past the impacts and ensuing fires.
Finally, the visual evidence of the slow pulling in of the perimeter columns clearly shows that it was the fire that was destroying the only reserve capacity the buildings had left, not explosives.
Arthur
QUOTE (adoucette+May 2 2007, 02:41 AM)
Except its a six legged structure and the operator takes out THREE legs on one side (you can see that two are already cut right at the start of the video) so of course this otherwise rigid structure topples towards the side that has been removed.
Arthur
the broken piece stays in one piece, and tips over.
WHO cares how many legs it had. once the 'DCR' is overcome, there are more similarities than differences.
same with the concrete building, which is far more brittle than the towers were. it tips over on a pivot, and doesn't shatter until it meets an opposing force(the building across the street).
same with ALL buildings that can stand the lateral force of a hurricane. they stay together in one piece unless they meet an opposing force greater than their integral strength.
in the case of the towers, you and the rest of the NWO would have us believe that the path of least resistance was through the towers, and not through the air.
the towers took the path of most resistance. even an idiot can see that it's easier to fall through air than it is to fall through a building.
Arthur
the broken piece stays in one piece, and tips over.
WHO cares how many legs it had. once the 'DCR' is overcome, there are more similarities than differences.
same with the concrete building, which is far more brittle than the towers were. it tips over on a pivot, and doesn't shatter until it meets an opposing force(the building across the street).
same with ALL buildings that can stand the lateral force of a hurricane. they stay together in one piece unless they meet an opposing force greater than their integral strength.
in the case of the towers, you and the rest of the NWO would have us believe that the path of least resistance was through the towers, and not through the air.
the towers took the path of most resistance. even an idiot can see that it's easier to fall through air than it is to fall through a building.
Newton,
If the top block falls without pancaking, i.e. the floors below are destroyed and become a random mess that doesn't contribute to the collapsing mass then the block will after a couple of stories leave the building. But it is assumed that the collapsing mass sticks together with the top block. Theoretically then even a 1000 story building is possible.
Arthur,
If the explosives were planted in the core (maybe with thermic isolation) then some went of at the plane impact, you won't notice that in the fuel fireball. And the rest is still intact and stays intact. A rocket fuel theory would immediately set the whole building on fire (if I understand that theory) after impact. If you are a demolitionist... then the most realistic version is a kind of high-tech devices in the core, maybe a few are destroyed at impact and the rest stays there. If you then finaly blow up the core then from the outside it looks gravity driven and is consistent with a failing core theory, a core that doesn't completely die but only the outer parts of the inner core to detach the trusses from it. But nobody knows what really happened. I don't know much about the formed spherical particles but NF is right that you have to come up with something, first they laugh at you...
If the top block falls without pancaking, i.e. the floors below are destroyed and become a random mess that doesn't contribute to the collapsing mass then the block will after a couple of stories leave the building. But it is assumed that the collapsing mass sticks together with the top block. Theoretically then even a 1000 story building is possible.
Arthur,
If the explosives were planted in the core (maybe with thermic isolation) then some went of at the plane impact, you won't notice that in the fuel fireball. And the rest is still intact and stays intact. A rocket fuel theory would immediately set the whole building on fire (if I understand that theory) after impact. If you are a demolitionist... then the most realistic version is a kind of high-tech devices in the core, maybe a few are destroyed at impact and the rest stays there. If you then finaly blow up the core then from the outside it looks gravity driven and is consistent with a failing core theory, a core that doesn't completely die but only the outer parts of the inner core to detach the trusses from it. But nobody knows what really happened. I don't know much about the formed spherical particles but NF is right that you have to come up with something, first they laugh at you...
http://www.youtube.com/watch?v=sWAcfEB9L8I...related&search=
What, concrete dust from a non explosive demolition?
What, concrete dust from a non explosive demolition?
Here another example
http://www.eurodemolition.com/Admin/movies...871imag0005.avi
Also in a normal CD the explosives are only the catalyst and gravity the engine.
http://www.eurodemolition.com/Admin/movies...871imag0005.avi
Also in a normal CD the explosives are only the catalyst and gravity the engine.
QUOTE (Capracus+May 1 2007, 09:12 AM)
For the doubters of gravitational collapse as a mechanism for the pulverization of concrete, here is an example of such from the collapse of the towers.
I forgot to mention that this is not debris from the twin towers, it's debris from the Margalla Towers in Pakistan. In 2005, two blocks of the 19 story Margalla Towers collapsed during a 7.6 magnitude earthquake. This gravity collapse, like the WTC collapses, produced volumes of concrete dust and debris.
I forgot to mention that this is not debris from the twin towers, it's debris from the Margalla Towers in Pakistan. In 2005, two blocks of the 19 story Margalla Towers collapsed during a 7.6 magnitude earthquake. This gravity collapse, like the WTC collapses, produced volumes of concrete dust and debris.
QUOTE (einsteen+May 2 2007, 10:50 AM)
Also in a normal CD the explosives are only the catalyst and gravity the engine.
Einsteen, you know it, I know it, now try to convince your fellow CTs of this fact. A good number of them are under the assumption that a gravity driven collapse cannot produce the fine concrete dust exhibited in the WTC collapses.
QUOTE (newton+May 2 2007, 02:02 AM)
another demonstration of what structures that are designed to stand up act like when you pull the legs out....
youtube: tower gets downed by psycho machine operator
Thanks, good video!
I would have liked to see them lift the top with a crane by a floor height and drop it on the rest of the structure though...
youtube: tower gets downed by psycho machine operator
Thanks, good video!
I would have liked to see them lift the top with a crane by a floor height and drop it on the rest of the structure though...
QUOTE (newton+May 2 2007, 12:02 AM)
the broken piece stays in one piece, and tips over.
WHO cares how many legs it had. once the 'DCR' is overcome, there are more similarities than differences.
same with the concrete building, which is far more brittle than the towers were. it tips over on a pivot, and doesn't shatter until it meets an opposing force(the building across the street).
same with ALL buildings that can stand the lateral force of a hurricane. they stay together in one piece unless they meet an opposing force greater than their integral strength.
in the case of the towers, you and the rest of the NWO would have us believe that the path of least resistance was through the towers, and not through the air.
the towers took the path of most resistance. even an idiot can see that it's easier to fall through air than it is to fall through a building.
Except the failure modes are distinctly different.
In these towers the DCR of the remaining legs is NOT OVERCOME (at the end you will see the legs on the left side, still intact).
http://www.youtube.com/watch?v=sWAcfEB9L8I
The structure is an empty six legged concrete water tower (you see a little water at the end, but clearly the tank is essentially empty).
Thus there is PLENTY of reserve strength in the three remaining legs as they are undamaged, but they can't hold the tower vertical when all the legs on one side are cut.
Regardless of what YOU think you can see, the towers didn't get a choice as to which path they were going to take.
Arthur
WHO cares how many legs it had. once the 'DCR' is overcome, there are more similarities than differences.
same with the concrete building, which is far more brittle than the towers were. it tips over on a pivot, and doesn't shatter until it meets an opposing force(the building across the street).
same with ALL buildings that can stand the lateral force of a hurricane. they stay together in one piece unless they meet an opposing force greater than their integral strength.
in the case of the towers, you and the rest of the NWO would have us believe that the path of least resistance was through the towers, and not through the air.
the towers took the path of most resistance. even an idiot can see that it's easier to fall through air than it is to fall through a building.
Except the failure modes are distinctly different.
In these towers the DCR of the remaining legs is NOT OVERCOME (at the end you will see the legs on the left side, still intact).
http://www.youtube.com/watch?v=sWAcfEB9L8I
The structure is an empty six legged concrete water tower (you see a little water at the end, but clearly the tank is essentially empty).
Thus there is PLENTY of reserve strength in the three remaining legs as they are undamaged, but they can't hold the tower vertical when all the legs on one side are cut.
Regardless of what YOU think you can see, the towers didn't get a choice as to which path they were going to take.
Arthur
QUOTE (lozenge124+May 2 2007, 08:24 AM)
I would have liked to see them lift the top with a crane by a floor height and drop it on the rest of the structure though...
And in which case it would have likely failed progressively downward and not toppled over, as was the case when half of the supporting legs were cut.
Arthur
And in which case it would have likely failed progressively downward and not toppled over, as was the case when half of the supporting legs were cut.
Arthur
QUOTE (adoucette+May 2 2007, 01:43 PM)
And in which case it would have likely failed progressively downward and not toppled over, as was the case when half of the supporting legs were cut.
Arthur
Again, there is no reason to assume that the top floor would fail first, followed by the next floor, followed by the next floor etc... If you apply a downward force to the top of the structure increasing it until something breaks, the failure will occur at the floor that is the weakest link - this may or may not be the top floor.
Additionally, in the case of dropping the upper section on the structure, for a progressive collapse the six columns would have to fail at the same time on the same floor each time - statistically improbable.
This is similar to pulling on a chain until it breaks, you cannot tell which link will fail beforehand, but statistically speaking it will not always be one of the end-links.
Arthur
Again, there is no reason to assume that the top floor would fail first, followed by the next floor, followed by the next floor etc... If you apply a downward force to the top of the structure increasing it until something breaks, the failure will occur at the floor that is the weakest link - this may or may not be the top floor.
Additionally, in the case of dropping the upper section on the structure, for a progressive collapse the six columns would have to fail at the same time on the same floor each time - statistically improbable.
This is similar to pulling on a chain until it breaks, you cannot tell which link will fail beforehand, but statistically speaking it will not always be one of the end-links.
lozenge124
As has been pointed out numerous times, the frame members of the twin towers did not fail at all(other than in the impact area) but were completely bypassed by the failing floors, once unsupported they were simply pushed to the outside and fell over. So your supposed statistical improbability is irrelivent.
Grumpy
QUOTE
Additionally, in the case of dropping the upper section on the structure, for a progressive collapse the six columns would have to fail at the same time on the same floor each time - statistically improbable.
As has been pointed out numerous times, the frame members of the twin towers did not fail at all(other than in the impact area) but were completely bypassed by the failing floors, once unsupported they were simply pushed to the outside and fell over. So your supposed statistical improbability is irrelivent.
Grumpy
You say it has been pointed out, but I think that discussion is not finished, in the past Lozenge provided an animated gif about the collapse. A couple of questions to be solved are
- The funneling/wedging of mass, this is an assumption and NIST didn't mention it as far as I remember. If you animate that how would that exactly look ? The only realistic thing I can think about is that the floors are detached from the upper block.
- If the NIST says the core failed first do they mean that the trusses are detached or do they mean the core sags in? It is not strange that these questions are unanswered since only initiation matters for them.
- The energy absorption per storey. Yes even if Gordon Ross's math is wrong (I never went through it) the question remains. If energy can not travel more than one story then it is also consistent with a demolition.
etc.
- The funneling/wedging of mass, this is an assumption and NIST didn't mention it as far as I remember. If you animate that how would that exactly look ? The only realistic thing I can think about is that the floors are detached from the upper block.
- If the NIST says the core failed first do they mean that the trusses are detached or do they mean the core sags in? It is not strange that these questions are unanswered since only initiation matters for them.
- The energy absorption per storey. Yes even if Gordon Ross's math is wrong (I never went through it) the question remains. If energy can not travel more than one story then it is also consistent with a demolition.
etc.
QUOTE (einsteen+May 2 2007, 11:08 AM)
You say it has been pointed out, but I think that discussion is not finished,
LOOK AT THE FRIGGIN PICTURES.
They've only been posted a hundred times or so.
They CLEARLY show the sides of the towers laid out and the vast majority of the perimeter columns damn near pristine.
You can't IGNORE the details of HOW the towers were constructed. The floors were connected to the inner and outer tubes of the towers, but provided no extra support to anything but their floor loads. The majority of the exterior columns were simply bolted to each other (only the mechanical floors were welded)
Arthur
LOOK AT THE FRIGGIN PICTURES.
They've only been posted a hundred times or so.
They CLEARLY show the sides of the towers laid out and the vast majority of the perimeter columns damn near pristine.
You can't IGNORE the details of HOW the towers were constructed. The floors were connected to the inner and outer tubes of the towers, but provided no extra support to anything but their floor loads. The majority of the exterior columns were simply bolted to each other (only the mechanical floors were welded)
Arthur
QUOTE (Grumpy+May 2 2007, 03:39 PM)
lozenge124
As has been pointed out numerous times, the frame members of the twin towers did not fail at all(other than in the impact area) but were completely bypassed by the failing floors, once unsupported they were simply pushed to the outside and fell over. So your supposed statistical improbability is irrelivent.
Grumpy
This is the structure we are talking about, not the WTC:
I wish I still had the ability to create an FEA model of such a structure, as really it is quite simple. Does anyone here have access to software to do this?
Incidentally, I don't think even the NIST supports your idea that the "frame members" "were simply pushed to the outside and fell over.", nor that the floors bypassed the perimeter and core columns first. Their theory is a kind of upper block piledriver which crushes the bottom structure floor by floor.
As has been pointed out numerous times, the frame members of the twin towers did not fail at all(other than in the impact area) but were completely bypassed by the failing floors, once unsupported they were simply pushed to the outside and fell over. So your supposed statistical improbability is irrelivent.
Grumpy
This is the structure we are talking about, not the WTC:
I wish I still had the ability to create an FEA model of such a structure, as really it is quite simple. Does anyone here have access to software to do this?
Incidentally, I don't think even the NIST supports your idea that the "frame members" "were simply pushed to the outside and fell over.", nor that the floors bypassed the perimeter and core columns first. Their theory is a kind of upper block piledriver which crushes the bottom structure floor by floor.
QUOTE (lozenge124+May 2 2007, 12:05 PM)
Incidentally, I don't think even the NIST supports your idea that the "frame members" "were simply pushed to the outside and fell over.", nor that the floors bypassed the perimeter and core columns first. Their theory is a kind of upper block piledriver wish crushes the bottom structure floor by floor.
Crushes the bottom FLOORS, but NOT the columns.
They DO support this idea via their analysis of the failed seats being primarily downward below the point of impact and their description of the failure mode (after initiation) as "pancaking".
Arthur
QUOTE (adoucette+May 2 2007, 05:13 PM)
Crushes the bottom FLOORS, but NOT the columns.
They DO support this idea via their analysis of the failed seats being primarily downward below the point of impact and their description of the failure mode (after initiation) as "pancaking".
Arthur
We've argued this before, but the NIST faq clearly states that they do not support a "progressive failure of the floor systems".
I think it would be more fruitful to test your assertion that this structure would collapse progressively if the upper floor was lifted and dropped down, because it is a fairly simple system that can be modelled (even if "gravity doesn't scale"):
They DO support this idea via their analysis of the failed seats being primarily downward below the point of impact and their description of the failure mode (after initiation) as "pancaking".
Arthur
We've argued this before, but the NIST faq clearly states that they do not support a "progressive failure of the floor systems".
QUOTE
NIST’s findings do not support the “pancake theory” of collapse, which is premised on a progressive failure of the floor systems in the WTC towers (the composite floor system—that connected the core columns and the perimeter columns—consisted of a grid of steel “trusses” integrated with a concrete slab; see diagram below). Instead, the NIST investigation showed conclusively that the failure of the inwardly bowed perimeter columns initiated collapse and that the occurrence of this inward bowing required the sagging floors to remain connected to the columns and pull the columns inwards. Thus, the floors did not fail progressively to cause a pancaking phenomenon.
http://wtc.nist.gov/pubs/factsheets/faqs_8_2006.htmI think it would be more fruitful to test your assertion that this structure would collapse progressively if the upper floor was lifted and dropped down, because it is a fairly simple system that can be modelled (even if "gravity doesn't scale"):
QUOTE (lozenge124+May 2 2007, 12:25 PM)
We've argued this before, but the NIST faq clearly states that they do not support a "progressive failure of the floor systems".
http://wtc.nist.gov/pubs/factsheets/faqs_8_2006.htm
I think it would be more fruitful to test your assertion that this structure would collapse progressively if the upper floor was lifted and dropped down, because it is a fairly simple system that can be modelled (even if "gravity doesn't scale"):
That NIST FAQ has to do with COLLAPSE INITIATION.
That has NOTHING to do with collapse progression.
In that, they DO use the term "pancaking" to describe how the collapse progresses.
See: NIST NCSTAR 1-3C Sect 3.5.3
...
Failure of the gusset plate welded to the top of the truss chord was again almost exclusively observed regardless of location. This may be a result of overloading the lower floors as the floors above were "pan-caking".
For that water tower to collapse progressively simply fill the tank with water and then drop it and the top floor 12 ft onto the next lower floor.
Why fill the tank? Because it would take that for the loads on the structure to be reasonably appropriate.
Arthur
http://wtc.nist.gov/pubs/factsheets/faqs_8_2006.htm
I think it would be more fruitful to test your assertion that this structure would collapse progressively if the upper floor was lifted and dropped down, because it is a fairly simple system that can be modelled (even if "gravity doesn't scale"):
That NIST FAQ has to do with COLLAPSE INITIATION.
That has NOTHING to do with collapse progression.
In that, they DO use the term "pancaking" to describe how the collapse progresses.
See: NIST NCSTAR 1-3C Sect 3.5.3
...
Failure of the gusset plate welded to the top of the truss chord was again almost exclusively observed regardless of location. This may be a result of overloading the lower floors as the floors above were "pan-caking".
For that water tower to collapse progressively simply fill the tank with water and then drop it and the top floor 12 ft onto the next lower floor.
Why fill the tank? Because it would take that for the loads on the structure to be reasonably appropriate.
Arthur
QUOTE (adoucette+May 2 2007, 06:05 PM)
That NIST FAQ has to do with COLLAPSE INITIATION.
There is nothing in the faq that supports your premise. Repeating it over and over will not make it true. The NIST is quite clear:
"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"
I'm familiar with this quote, NCSTAR 1-3 is entitled "Mechanical and Metallurgical Analysis of Structural Steel", the quote is not from NCSTAR 1-6 "Structural Fire Response and Probable Collapse Sequence of the World Trade Center Towers".
In a "piledriver" collapse, floors are going to be hitting each other as the upper block descends into the lower block so I can see why the NIST might use the term "pan-caking" in quotes to describe this. Especially in a section that is looking to explain the causes of certain properties of the structural steel after collapse.
I'm familiar with this quote, NCSTAR 1-3 is entitled "Mechanical and Metallurgical Analysis of Structural Steel", the quote is not from NCSTAR 1-6 "Structural Fire Response and Probable Collapse Sequence of the World Trade Center Towers".
In a "piledriver" collapse, floors are going to be hitting each other as the upper block descends into the lower block so I can see why the NIST might use the term "pan-caking" in quotes to describe this. Especially in a section that is looking to explain the causes of certain properties of the structural steel after collapse.
For that water tower to collapse progressively simply fill the tank with water and then drop it and the top floor 12 ft onto the next lower floor.
Why fill the tank? Because it would take that for the loads on the structure to be reasonably appropriate.
Again, it might fail progressively, or it might not. One of the lower floors may fail before the top one, especially given the state of the tower. I refer you again to the chain example I gave before.
This tower is actually a better candidate for progressive collapse than the WTC, because the floors act as separators between the support columns - the floors will redistribute the load across the columns of a floor if the floor above it loses a column. Also the support columns are not vertical but lean outwards. But, again the 1st floor to fail will not necessarily be the top one.
"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"
"pancake theory of collapse", not "pancake theory of collapse initiation"!
A "pancake theory of collapse initiation" doesn't even make any sense! Once the upper block, or a floor, has dropped down a floor length that's it, you are in the collapse phase, not the collapse initation phase.
As you know, NIST was trying to find out how the COLLAPSE STARTED.
They did not study how the collapse progressed.
So, CLEARLY this is in regard to how the Collapse Initiated and was SPECIFICALLY showing that they disagreed with the conclusions that FEMA had come to.
Except that is exactly what FEMA suggested.
See: FEMA 403 - Chap 2 WTC 1 & 2 Sec 2.2.1.4 & Fig 2-21 - Buckling of Columns initiated by failure of Floor Framing and Connections.
By the way, FEMA did address the collapse progression See 2.2.1.5 Collapse Progression
Perimeter Walls of the building seemed to have peeled off and fallen directly away from the building face....
Arthur
The NIST faq seemed to be in response to the many questions and critiques that were brought up after the NIST report came out. One of the critiques was of course that the report didn't go beyond collapse initation, so I don't agree with your conclusion that the faq also constrains itself to initation. (in any case the wording of the faq is quite clear)
The NIST faq seemed to be in response to the many questions and critiques that were brought up after the NIST report came out. One of the critiques was of course that the report didn't go beyond collapse initation, so I don't agree with your conclusion that the faq also constrains itself to initation. (in any case the wording of the faq is quite clear)
Except that is exactly what FEMA suggested.
See: FEMA 403 - Chap 2 WTC 1 & 2 Sec 2.2.1.4 & Fig 2-21 - Buckling of Columns initiated by failure of Floor Framing and Connections.
By the way, FEMA did address the collapse progression See 2.2.1.5 Collapse Progression
Perimeter Walls of the building seemed to have peeled off and fallen directly away from the building face....
I see the word "initiated" yes, but not pancaking. According to FEMA, the pancaking was initiated by the failure of the floor framing/connections OK - I don't quite see your point here.
There is nothing in the faq that supports your premise. Repeating it over and over will not make it true. The NIST is quite clear:
"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"
QUOTE
See: NIST NCSTAR 1-3C Sect 3.5.3
I'm familiar with this quote, NCSTAR 1-3 is entitled "Mechanical and Metallurgical Analysis of Structural Steel", the quote is not from NCSTAR 1-6 "Structural Fire Response and Probable Collapse Sequence of the World Trade Center Towers".
In a "piledriver" collapse, floors are going to be hitting each other as the upper block descends into the lower block so I can see why the NIST might use the term "pan-caking" in quotes to describe this. Especially in a section that is looking to explain the causes of certain properties of the structural steel after collapse.
QUOTE (->
| QUOTE |
| See: NIST NCSTAR 1-3C Sect 3.5.3 |
I'm familiar with this quote, NCSTAR 1-3 is entitled "Mechanical and Metallurgical Analysis of Structural Steel", the quote is not from NCSTAR 1-6 "Structural Fire Response and Probable Collapse Sequence of the World Trade Center Towers".
In a "piledriver" collapse, floors are going to be hitting each other as the upper block descends into the lower block so I can see why the NIST might use the term "pan-caking" in quotes to describe this. Especially in a section that is looking to explain the causes of certain properties of the structural steel after collapse.
For that water tower to collapse progressively simply fill the tank with water and then drop it and the top floor 12 ft onto the next lower floor.
Why fill the tank? Because it would take that for the loads on the structure to be reasonably appropriate.
Again, it might fail progressively, or it might not. One of the lower floors may fail before the top one, especially given the state of the tower. I refer you again to the chain example I gave before.
This tower is actually a better candidate for progressive collapse than the WTC, because the floors act as separators between the support columns - the floors will redistribute the load across the columns of a floor if the floor above it loses a column. Also the support columns are not vertical but lean outwards. But, again the 1st floor to fail will not necessarily be the top one.
QUOTE (David B. Benson+May 1 2007, 06:44 PM)
Wrong again. A well done CD will provide drops giving an acceleration close to g. Otherwise, one needs enough data to distinguish crush-down from crush-up, assuming one is not allowed to actual see which of the two is occurring.
Roughly, crush-down involves conservation of momentum while crush-up does not. There are further distinguishing details.
Anyway, the simplest way to see that the collapse of the towers was not a well done CD is to determine the value for a is the equation
d = (1/2)at^2
The best fit to NEU-FONZE's measurements is
WTC 1: a = 0.66g
WTC 2: a = 0.75g
both of which show that the towers were offering some resistance. The fit to the crush-down equation is much better than to the simple parabola.
You have no basis for making the claim that a demolition of WTC 1 and 2 of the type
used will "provide drops giving an acceleration close to g". That is simply uninformed
opinion which you are attempting to pass off as fact.
The so-called "crush-down equations" can be made to fit any relatively smooth drop
data by choosing the parameters appropriately. They can be made to fit demolition
data (witness Greening's application to WTC 7). Hence, again, they are useless for
determining the nature of the destruction. That you believe otherwise represents the
agenda you are pushing. The reliance of the equations on unvalidated, and quite
likely invalid, assumptions (or hypotheses if you prefer) adds to their dubious nature.
Roughly, crush-down involves conservation of momentum while crush-up does not. There are further distinguishing details.
Anyway, the simplest way to see that the collapse of the towers was not a well done CD is to determine the value for a is the equation
d = (1/2)at^2
The best fit to NEU-FONZE's measurements is
WTC 1: a = 0.66g
WTC 2: a = 0.75g
both of which show that the towers were offering some resistance. The fit to the crush-down equation is much better than to the simple parabola.
You have no basis for making the claim that a demolition of WTC 1 and 2 of the type
used will "provide drops giving an acceleration close to g". That is simply uninformed
opinion which you are attempting to pass off as fact.
The so-called "crush-down equations" can be made to fit any relatively smooth drop
data by choosing the parameters appropriately. They can be made to fit demolition
data (witness Greening's application to WTC 7). Hence, again, they are useless for
determining the nature of the destruction. That you believe otherwise represents the
agenda you are pushing. The reliance of the equations on unvalidated, and quite
likely invalid, assumptions (or hypotheses if you prefer) adds to their dubious nature.
QUOTE (lozenge124+May 2 2007, 01:41 PM)
There is nothing in the faq that supports your premise. Repeating it over and over will not make it true. The NIST is quite clear:
"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"
Again, that FAQ is very specifically discussing how the collapse INITIATES.
They were very specifically REFUTING previously published explanations for COLLAPSE INITIATION.
The OTHER NIST chapter is CLEARLY talking about the damage done DURING the collapse.
So NO, NIST does not believe that the collapse BEGAN by the pancaking of floors, but YES, NIST supports the fact that the floors PANCAKED once the collapse was underway.
Arthur
"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"
Again, that FAQ is very specifically discussing how the collapse INITIATES.
They were very specifically REFUTING previously published explanations for COLLAPSE INITIATION.
The OTHER NIST chapter is CLEARLY talking about the damage done DURING the collapse.
So NO, NIST does not believe that the collapse BEGAN by the pancaking of floors, but YES, NIST supports the fact that the floors PANCAKED once the collapse was underway.
Arthur
QUOTE (lozenge124+May 2 2007, 01:41 PM)
Again, it might fail progressively, or it might not. One of the lower floors may fail before the top one, especially given the state of the tower. I refer you again to the chain example I gave before.
This tower is actually a better candidate for progressive collapse than the WTC, because the floors act as separators between the support columns - the floors will redistribute the load across the columns of a floor if the floor above it loses a column. Also the support columns are not vertical but lean outwards. But, again the 1st floor to fail will not necessarily be the top one.
Your chain analogy is pointless.
The floors of a building are not all the same relative strength.
Specifically they tend to DECREASE as they go up becuase the loads decrease as you go up.
This was MOST CERTAINLY the case in the WTC towers.
So expecting a LOWER but STRONGER floor to fail first makes NO SENSE.
Arthur
This tower is actually a better candidate for progressive collapse than the WTC, because the floors act as separators between the support columns - the floors will redistribute the load across the columns of a floor if the floor above it loses a column. Also the support columns are not vertical but lean outwards. But, again the 1st floor to fail will not necessarily be the top one.
Your chain analogy is pointless.
The floors of a building are not all the same relative strength.
Specifically they tend to DECREASE as they go up becuase the loads decrease as you go up.
This was MOST CERTAINLY the case in the WTC towers.
So expecting a LOWER but STRONGER floor to fail first makes NO SENSE.
Arthur
QUOTE (adoucette+May 2 2007, 07:09 PM)
Again, that FAQ is very specifically discussing how the collapse INITIATES.
They were very specifically REFUTING previously published explanations for COLLAPSE INITIATION.
The OTHER NIST chapter is CLEARLY talking about the damage done DURING the collapse.
So NO, NIST does not believe that the collapse BEGAN by the pancaking of floors, but YES, NIST supports the fact that the floors PANCAKED once the collapse was underway.
Arthur
"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"
"pancake theory of collapse", not "pancake theory of collapse initiation"!
A "pancake theory of collapse initiation" doesn't even make any sense! Once the upper block, or a floor, has dropped down a floor length that's it, you are in the collapse phase, not the collapse initation phase.
They were very specifically REFUTING previously published explanations for COLLAPSE INITIATION.
The OTHER NIST chapter is CLEARLY talking about the damage done DURING the collapse.
So NO, NIST does not believe that the collapse BEGAN by the pancaking of floors, but YES, NIST supports the fact that the floors PANCAKED once the collapse was underway.
Arthur
"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"
"pancake theory of collapse", not "pancake theory of collapse initiation"!
A "pancake theory of collapse initiation" doesn't even make any sense! Once the upper block, or a floor, has dropped down a floor length that's it, you are in the collapse phase, not the collapse initation phase.
QUOTE (lozenge124+May 2 2007, 02:14 PM)
"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"
"pancake theory of collapse", not "pancake theory of collapse initiation"!
A "pancake theory of collapse initiation" doesn't even make any sense! Once the upper block, or a floor, has dropped down a floor length that's it, you are in the collapse phase, not the collapse initation phase.
As you know, NIST was trying to find out how the COLLAPSE STARTED.
They did not study how the collapse progressed.
So, CLEARLY this is in regard to how the Collapse Initiated and was SPECIFICALLY showing that they disagreed with the conclusions that FEMA had come to.
QUOTE
A "pancake theory of collapse initiation" doesn't even make any sense!
Except that is exactly what FEMA suggested.
See: FEMA 403 - Chap 2 WTC 1 & 2 Sec 2.2.1.4 & Fig 2-21 - Buckling of Columns initiated by failure of Floor Framing and Connections.
By the way, FEMA did address the collapse progression See 2.2.1.5 Collapse Progression
Perimeter Walls of the building seemed to have peeled off and fallen directly away from the building face....
Arthur
QUOTE (adoucette+May 1 2007, 09:08 PM)
Nope,
The collapse clearly begins in BOTH towers on the fire and impact floors.
The collapse clearly begins BEFORE there is a large expulsion of flame and smoke.
There was no way to predict exactly which floors the terrorists would fly the planes into, thus making pre-planting of the explosives on the impact floors highly improbable.
And as highly improbable as that would be, there is no way that explosives could have survived on those floors an hour past the impacts and ensuing fires.
Finally, the visual evidence of the slow pulling in of the perimeter columns clearly shows that it was the fire that was destroying the only reserve capacity the buildings had left, not explosives.
My observations disagree with yours. I would recommend that others make their own
observations since this is an area accessible to anyone rather than accepting your
pronouncement, or mine or NISTS's, etc.
My observations lead me to conclude that the collapse did not begin on the impact
floors but with the core. Since the collapse did not begin on the impact floors it is
irrelevant that the location could not be predicted or that explosives would not
survive there. The visual evidence for a pre-collapse tilt of the upper blocks of WTC 1
and 2 is a myth manufactured by NIST. It uses pictures from after the onset of collapse
to support the notion that the tilt was pre-collapse.
The collapse clearly begins in BOTH towers on the fire and impact floors.
The collapse clearly begins BEFORE there is a large expulsion of flame and smoke.
There was no way to predict exactly which floors the terrorists would fly the planes into, thus making pre-planting of the explosives on the impact floors highly improbable.
And as highly improbable as that would be, there is no way that explosives could have survived on those floors an hour past the impacts and ensuing fires.
Finally, the visual evidence of the slow pulling in of the perimeter columns clearly shows that it was the fire that was destroying the only reserve capacity the buildings had left, not explosives.
My observations disagree with yours. I would recommend that others make their own
observations since this is an area accessible to anyone rather than accepting your
pronouncement, or mine or NISTS's, etc.
My observations lead me to conclude that the collapse did not begin on the impact
floors but with the core. Since the collapse did not begin on the impact floors it is
irrelevant that the location could not be predicted or that explosives would not
survive there. The visual evidence for a pre-collapse tilt of the upper blocks of WTC 1
and 2 is a myth manufactured by NIST. It uses pictures from after the onset of collapse
to support the notion that the tilt was pre-collapse.
QUOTE (eigenvalue+May 2 2007, 06:43 PM)
You have no basis for making the claim that a demolition of WTC 1 and 2 of the type used will "provide drops giving an acceleration close to g".
The so-called "crush-down equations" can be made to fit any relatively smooth drop data by choosing the parameters appropriately.
The reliance of the equations on unvalidated, and quite
likely invalid, assumptions (or hypotheses if you prefer) adds to their dubious nature.
But I do. I've read quite a bit now about how so-called implosion demolitions are done. You might start by reading Bylses' Rubble.
The second sentence quoted above is sheer nonsense as it stands. Properly reformulated, you might have a chance of defending it.
I validated the crush-down equation using actual data. Quit repeating an untruth.
Which of the four hypotheses do you consider to be invalid? All four seem reasonable to people who actually understand physics. Hmmm, are you just trolling?
The so-called "crush-down equations" can be made to fit any relatively smooth drop data by choosing the parameters appropriately.
The reliance of the equations on unvalidated, and quite
likely invalid, assumptions (or hypotheses if you prefer) adds to their dubious nature.
But I do. I've read quite a bit now about how so-called implosion demolitions are done. You might start by reading Bylses' Rubble.
The second sentence quoted above is sheer nonsense as it stands. Properly reformulated, you might have a chance of defending it.
I validated the crush-down equation using actual data. Quit repeating an untruth.
Which of the four hypotheses do you consider to be invalid? All four seem reasonable to people who actually understand physics. Hmmm, are you just trolling?
QUOTE
As you know, NIST was trying to find out how the COLLAPSE STARTED.
They did not study how the collapse progressed.
So, CLEARLY this is in regard to how the Collapse Initiated and was SPECIFICALLY showing that they disagreed with the conclusions that FEMA had come to.
They did not study how the collapse progressed.
So, CLEARLY this is in regard to how the Collapse Initiated and was SPECIFICALLY showing that they disagreed with the conclusions that FEMA had come to.
The NIST faq seemed to be in response to the many questions and critiques that were brought up after the NIST report came out. One of the critiques was of course that the report didn't go beyond collapse initation, so I don't agree with your conclusion that the faq also constrains itself to initation. (in any case the wording of the faq is quite clear)
QUOTE (->
| QUOTE |
| As you know, NIST was trying to find out how the COLLAPSE STARTED. They did not study how the collapse progressed. So, CLEARLY this is in regard to how the Collapse Initiated and was SPECIFICALLY showing that they disagreed with the conclusions that FEMA had come to. |
The NIST faq seemed to be in response to the many questions and critiques that were brought up after the NIST report came out. One of the critiques was of course that the report didn't go beyond collapse initation, so I don't agree with your conclusion that the faq also constrains itself to initation. (in any case the wording of the faq is quite clear)
Except that is exactly what FEMA suggested.
See: FEMA 403 - Chap 2 WTC 1 & 2 Sec 2.2.1.4 & Fig 2-21 - Buckling of Columns initiated by failure of Floor Framing and Connections.
By the way, FEMA did address the collapse progression See 2.2.1.5 Collapse Progression
Perimeter Walls of the building seemed to have peeled off and fallen directly away from the building face....
I see the word "initiated" yes, but not pancaking. According to FEMA, the pancaking was initiated by the failure of the floor framing/connections OK - I don't quite see your point here.
QUOTE (eigenvalue+May 2 2007, 07:38 PM)
The visual evidence for a pre-collapse tilt of the upper blocks of WTC 1 and 2 is a myth manufactured by NIST. It uses pictures from after the onset of collapse to support the notion that the tilt was pre-collapse.
Wrong again. The pre-collapse tilt is determined from the videos. This is easy to see for WTC 2 but quite a subtle matter for WTC 1, where the tilt is quite small.
But what happens to the top of a column that begins to buckle? Then use some simple geometric reasoning.
Wrong again. The pre-collapse tilt is determined from the videos. This is easy to see for WTC 2 but quite a subtle matter for WTC 1, where the tilt is quite small.
But what happens to the top of a column that begins to buckle? Then use some simple geometric reasoning.
QUOTE (David B. Benson+May 2 2007, 01:13 PM)
Wrong again. The pre-collapse tilt is determined from the videos. This is easy to see for WTC 2 but quite a subtle matter for WTC 1, where the tilt is quite small.
It is apparent to me that the videos show no tilt until after the onset of collapse. I leave others to decide for themselves. If you have viewed the videos and this is your conclusion then so be it. I do hope others are not so easily swayed by your mere pronouncement.
It is apparent to me that the videos show no tilt until after the onset of collapse. I leave others to decide for themselves. If you have viewed the videos and this is your conclusion then so be it. I do hope others are not so easily swayed by your mere pronouncement.
QUOTE (David B. Benson+May 2 2007, 12:59 PM)
But I do. I've read quite a bit now about how so-called implosion demolitions are done. You might start by reading Bylses' Rubble.
David, you have consistently distorted what I have tried clearly to say in each of my posts. The above is the latest example. It is not possible to engage in a discussion under these conditions.
David, you have consistently distorted what I have tried clearly to say in each of my posts. The above is the latest example. It is not possible to engage in a discussion under these conditions.
QUOTE (eigenvalue+May 2 2007, 09:05 PM)
It is apparent to me that the videos show no tilt until after the onset of collapse. I leave others to decide for themselves. If you have viewed the videos and this is your conclusion then so be it. I do hope others are not so easily swayed by your mere pronouncement.
No, everybody ought to read what evidence NIST has. And just because you cannot see the tilt does not mean that NIST, with a pixel by pixel scan, could not determine this.
No, everybody ought to read what evidence NIST has. And just because you cannot see the tilt does not mean that NIST, with a pixel by pixel scan, could not determine this.
QUOTE (eigenvalue+May 2 2007, 09:13 PM)
David, you have consistently distorted what I have tried clearly to say in each of my posts. The above is the latest example. ...
You clearly stated that I didn't know what I was talking about. I corrected you. That is hardly a distortion.
I agree that the exchange of only electronic messages leads to misunderstandings, especially if the writer does not take great care to be precise. Even then misunderstandings can arise.
So I will try once more. Given enough data, crush-down can be distinguished from crush-up. A properly done implosion demolition causes the building to fall essentially without resistance, the limiting case of crush-down.
You clearly stated that I didn't know what I was talking about. I corrected you. That is hardly a distortion.
I agree that the exchange of only electronic messages leads to misunderstandings, especially if the writer does not take great care to be precise. Even then misunderstandings can arise.
So I will try once more. Given enough data, crush-down can be distinguished from crush-up. A properly done implosion demolition causes the building to fall essentially without resistance, the limiting case of crush-down.
QUOTE (adoucette+May 1 2007, 07:39 PM)
Its pretty much a given, if the subject is SCIENCE then the TNYT is probably in error.
IIRC even FEMA believed that the antenna fell into the building, but it was NIST with their much more extensive video & picture database who realized that the apparent downward movement was caused by the tilting away from those North face views.
Arthur
See how the confusion keeps circulating? David B. posts a link to support something he is saying. Within that link there is material which does not agree with what you guys are saying. So you just switch gears, shoot down the messenger, and move on.
IIRC even FEMA believed that the antenna fell into the building, but it was NIST with their much more extensive video & picture database who realized that the apparent downward movement was caused by the tilting away from those North face views.
Arthur
See how the confusion keeps circulating? David B. posts a link to support something he is saying. Within that link there is material which does not agree with what you guys are saying. So you just switch gears, shoot down the messenger, and move on.
QUOTE (forthetrees+May 2 2007, 10:18 PM)
Within that link there is material which does not agree with what you guys are saying.
How old is the TNYT article?
In the meantime, more has been learned about the collapses. But you'll perhaps be interested to learn that air resistance played a role during the latter portion of the collapses. Just not as large as the major contributors, but this does help explain why the collapses took so very long...
How old is the TNYT article?
In the meantime, more has been learned about the collapses. But you'll perhaps be interested to learn that air resistance played a role during the latter portion of the collapses. Just not as large as the major contributors, but this does help explain why the collapses took so very long...
QUOTE (lozenge124+May 2 2007, 03:08 PM)
I see the word "initiated" yes, but not pancaking. According to FEMA, the pancaking was initiated by the failure of the floor framing/connections OK - I don't quite see your point here.
You are right, the wording is quite clear.
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.
The ONLY place you will read about the "PANCAKE THEORY" is in relation to HOW the collapse started.
As in the FEMA report I directed you too.
and YES, FEMA was the one who came up with this theory and DOES USE THE TERM PANCAKE.
See Second Bullet FEMA - Chap 2 Page 2-25.
Arthur
You are right, the wording is quite clear.
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.
The ONLY place you will read about the "PANCAKE THEORY" is in relation to HOW the collapse started.
As in the FEMA report I directed you too.
and YES, FEMA was the one who came up with this theory and DOES USE THE TERM PANCAKE.
See Second Bullet FEMA - Chap 2 Page 2-25.
Arthur
QUOTE (eigenvalue+May 2 2007, 02:38 PM)
My observations lead me to conclude that the collapse did not begin on the impact floors but with the core. Since the collapse did not begin on the impact floors it is irrelevant that the location could not be predicted or that explosives would not survive there. The visual evidence for a pre-collapse tilt of the upper blocks of WTC 1 and 2 is a myth manufactured by NIST. It uses pictures from after the onset of collapse
to support the notion that the tilt was pre-collapse.
OK, so according to you NIST is IN ON IT?
And you had been doing reasonably well for a CT'er RIGHT until then.
Amazing to me how you can ignore the SLOW BOWING in of a WALL on BOTH TOWERS.
Amazing to me how you can conclude that if it was the core that failed, that that failure didn't occur at the impact floors, since CLEARLY there is NO FAILURES of the towers BELOW the fire floors, UNTIL the collapse front reaches them.
Arthur
to support the notion that the tilt was pre-collapse.
OK, so according to you NIST is IN ON IT?
And you had been doing reasonably well for a CT'er RIGHT until then.
Amazing to me how you can ignore the SLOW BOWING in of a WALL on BOTH TOWERS.
Amazing to me how you can conclude that if it was the core that failed, that that failure didn't occur at the impact floors, since CLEARLY there is NO FAILURES of the towers BELOW the fire floors, UNTIL the collapse front reaches them.
Arthur
Arthur --- He also ignores the damage to the core on impacted and fire affected floors. 
QUOTE (David B. Benson+May 2 2007, 02:33 PM)
You clearly stated that I didn't know what I was talking about. I corrected you. That is hardly a distortion.
I agree that the exchange of only electronic messages leads to misunderstandings, especially if the writer does not take great care to be precise. Even then misunderstandings can arise.
So I will try once more. Given enough data, crush-down can be distinguished from crush-up. A properly done implosion demolition causes the building to fall essentially without resistance, the limiting case of crush-down.
No, that is not what I stated. Reread my post. I stated that you had no basis for making
the claim you made. It is outside my control if you choose to interpret this as saying
you don't know what you are talking about. If you were to correct my actual statement
you would provide the basis that I claim you lack. Instead you changed the meaning of
what I said and then say I am wrong about this changed meaning. This appeared to me
to be a deliberate tactic, and, if so, it makes discussion impossible. In an exchange of electronic
messages you must do more than just take care to write precisely, you must also try to
read precisely. To help you out, I was neither explicitly nor implicitly referring to an
implosion demolition.
I agree that the exchange of only electronic messages leads to misunderstandings, especially if the writer does not take great care to be precise. Even then misunderstandings can arise.
So I will try once more. Given enough data, crush-down can be distinguished from crush-up. A properly done implosion demolition causes the building to fall essentially without resistance, the limiting case of crush-down.
No, that is not what I stated. Reread my post. I stated that you had no basis for making
the claim you made. It is outside my control if you choose to interpret this as saying
you don't know what you are talking about. If you were to correct my actual statement
you would provide the basis that I claim you lack. Instead you changed the meaning of
what I said and then say I am wrong about this changed meaning. This appeared to me
to be a deliberate tactic, and, if so, it makes discussion impossible. In an exchange of electronic
messages you must do more than just take care to write precisely, you must also try to
read precisely. To help you out, I was neither explicitly nor implicitly referring to an
implosion demolition.
QUOTE (eigenvalue+May 2 2007, 06:43 PM)
You have no basis for making the claim that a demolition of WTC 1 and 2 of the type used will "provide drops giving an acceleration close to g".
But I specifically stated a well done CD.
If your are imagining something other than a well done CD, then you should have specifically said so. It would have avoided this rathr pointless exchange.
But I specifically stated a well done CD.
If your are imagining something other than a well done CD, then you should have specifically said so. It would have avoided this rathr pointless exchange.
QUOTE (eigenvalue+May 3 2007, 02:12 AM)
I stated that you had no basis for making the claim you made.
But from this, it seems you were referring to a well done CD. If so, then you are once again simply wrong. The only well done CD for such structures would have to be an implosion.
But from this, it seems you were referring to a well done CD. If so, then you are once again simply wrong. The only well done CD for such structures would have to be an implosion.
QUOTE (forthetrees+May 2 2007, 05:18 PM)
See how the confusion keeps circulating? David B. posts a link to support something he is saying. Within that link there is material which does not agree with what you guys are saying. So you just switch gears, shoot down the messenger, and move on.
David posted a link to a map of the damage to WTC basement.
It appears to be in reasonable aggrement with the LERA analysis.
But the link you followed:
March 29th - Report on Collapse.
The Report that link is talking about was the FEMA report.
As I posted earlier, FEMA thought that the antenna had first started to fall into the tower but it took NIST, with its more extensive Video and time stamped picture library, to determine that this was an illusion caused by the angle the video was taken from.
Arthur
David posted a link to a map of the damage to WTC basement.
It appears to be in reasonable aggrement with the LERA analysis.
But the link you followed:
March 29th - Report on Collapse.
The Report that link is talking about was the FEMA report.
As I posted earlier, FEMA thought that the antenna had first started to fall into the tower but it took NIST, with its more extensive Video and time stamped picture library, to determine that this was an illusion caused by the angle the video was taken from.
Arthur
QUOTE (David B. Benson+May 2 2007, 11:20 PM)
How old is the TNYT article?
In the meantime, more has been learned about the collapses. But you'll perhaps be interested to learn that air resistance played a role during the latter portion of the collapses. Just not as large as the major contributors, but this does help explain why the collapses took so very long...
You tell me, David. You posted it just the other day to support something you were saying:
------------------------------------------------------------------------------------
David B. Benson Posted: Apr 30 2007, 10:03 PM Report this post · Quote
Advanced Member
Group: Members
Posts: 1053
Joined: 1-June 06
Positive Feedback: 100%
Feedback Score: 11
View/Add Feedback New
Warn: (0%)
QUOTE (lozenge124 @ Apr 30 2007, 09:35 PM)
a little more scientific acumen ...
All my life (well, ever since sixth grade) I've been trying to display a little more scientific acumen.
Guess I'll have to keep trying...
Anyway, here are two links to slightly different underground damage assessment maps.
Thanks to Arthur for relocating the second one.
TNYT Underground Damage
I quote from the place where I found this link: "In all there were 7 stories [down from the plaza level] of sublevels within the area west of the subway of which the lowest sublevel 6 was two stories high. The area east of the subway was 2 sublevels as depicted in the diagram."
Gif walk down the sublevels
-------------------------------------------------------------------------------------
So, is it still accurate for you guys to maintain that the collapse wave was nowhere near free fall speed, or in the interest of accuracy will someone who has the ability try to work out an equation to see just how close the collapse wave was to terminal velocity in the environment of the interior of the tower walls?
I'm sure you understand that it takes a skydiver in spread eagle position about 12 seconds to reach terminal velocity, so of course the collapse wave would not have been traveling at or near that speed until near the end. The whole point is that there seems to have been incredibly little resistance - if any at all - from the 2/3 or so of the towers which were undamaged.
In the meantime, more has been learned about the collapses. But you'll perhaps be interested to learn that air resistance played a role during the latter portion of the collapses. Just not as large as the major contributors, but this does help explain why the collapses took so very long...
You tell me, David. You posted it just the other day to support something you were saying:
------------------------------------------------------------------------------------
David B. Benson Posted: Apr 30 2007, 10:03 PM Report this post · Quote
Advanced Member
Group: Members
Posts: 1053
Joined: 1-June 06
Positive Feedback: 100%
Feedback Score: 11
View/Add Feedback New
Warn: (0%)
QUOTE (lozenge124 @ Apr 30 2007, 09:35 PM)
a little more scientific acumen ...
All my life (well, ever since sixth grade) I've been trying to display a little more scientific acumen.
Guess I'll have to keep trying...
Anyway, here are two links to slightly different underground damage assessment maps.
Thanks to Arthur for relocating the second one.
TNYT Underground Damage
I quote from the place where I found this link: "In all there were 7 stories [down from the plaza level] of sublevels within the area west of the subway of which the lowest sublevel 6 was two stories high. The area east of the subway was 2 sublevels as depicted in the diagram."
Gif walk down the sublevels
-------------------------------------------------------------------------------------
So, is it still accurate for you guys to maintain that the collapse wave was nowhere near free fall speed, or in the interest of accuracy will someone who has the ability try to work out an equation to see just how close the collapse wave was to terminal velocity in the environment of the interior of the tower walls?
I'm sure you understand that it takes a skydiver in spread eagle position about 12 seconds to reach terminal velocity, so of course the collapse wave would not have been traveling at or near that speed until near the end. The whole point is that there seems to have been incredibly little resistance - if any at all - from the 2/3 or so of the towers which were undamaged.
Good grief, Audie! "David posted a link to a map of the damage to WTC basement."
That's the same link you just told me wasn't worth a damn because in was in the NYT's.
It's OK to cite it when it suits your case, and then you turn right around and trash talk the exact same link when it doesn't?
You're a lawyer, aren't you.
That's the same link you just told me wasn't worth a damn because in was in the NYT's.
It's OK to cite it when it suits your case, and then you turn right around and trash talk the exact same link when it doesn't?
You're a lawyer, aren't you.
QUOTE (forthetrees+May 3 2007, 02:27 AM)
... The whole point is that there seems to have been incredibly little resistance - if any at all - from the 2/3 or so of the towers which were undamaged.
As I have previously posted, using the data provided by NEU-FONZE for the first few seconds of the collapses, the effective acceleration of the tower tops was
WTC 1: 0.66 g
WTC 2: 0.75 g
which for WTC 1 translates into an energy consumption of more than 500 MJ per story. That is only for the first 3 seconds. As the collapse progresses, the speed increases, but the acceleration decreases for several reasons, one of these being air resistance. From recent audio analysis of a video by shagster, it seems that the entire collapse of WTC 1 took 18 seconds. That's a long time, illustrating that there was considerable resistance, with much more than 500 MJ of energy consumption in the latter phases.
As I have previously posted, using the data provided by NEU-FONZE for the first few seconds of the collapses, the effective acceleration of the tower tops was
WTC 1: 0.66 g
WTC 2: 0.75 g
which for WTC 1 translates into an energy consumption of more than 500 MJ per story. That is only for the first 3 seconds. As the collapse progresses, the speed increases, but the acceleration decreases for several reasons, one of these being air resistance. From recent audio analysis of a video by shagster, it seems that the entire collapse of WTC 1 took 18 seconds. That's a long time, illustrating that there was considerable resistance, with much more than 500 MJ of energy consumption in the latter phases.
QUOTE (forthetrees+May 2 2007, 09:31 PM)
Good grief, Audie! "David posted a link to a map of the damage to WTC basement."
That's the same link you just told me wasn't worth a damn because in was in the NYT's.
It's OK to cite it when it suits your case, and then you turn right around and trash talk the exact same link when it doesn't?
You're a lawyer, aren't you.
You have to evaluate what you link to on its OWN MERITS.
David posted TWO sources of data for the destruction of the lower levels.
They were in general agreement.
But the one you linked to was basically just a few pieces from the FEMA report.
AT THE TIME (2002) that was the best information available, but much of it was simply educated speculaton.
But then the MUCH MORE DETAILED NIST (2005) report came out, with a great deal more effort put into assembling the evidence into an accurate timeline, modeling the towers, modeling the effect of the impact, modeling the fires and then putting all that together to see the global impact of all these forces on the overall structure.
This much more extensive investigation that NIST carried out corrected a number of speculative errors that were in the FEMA report.
Arthur
PS That comment about the TNYTs was actually just a little Global Warming humor as the TNYT's often seems to get the facts about that subject wrong.
That's the same link you just told me wasn't worth a damn because in was in the NYT's.
It's OK to cite it when it suits your case, and then you turn right around and trash talk the exact same link when it doesn't?
You're a lawyer, aren't you.
You have to evaluate what you link to on its OWN MERITS.
David posted TWO sources of data for the destruction of the lower levels.
They were in general agreement.
But the one you linked to was basically just a few pieces from the FEMA report.
AT THE TIME (2002) that was the best information available, but much of it was simply educated speculaton.
But then the MUCH MORE DETAILED NIST (2005) report came out, with a great deal more effort put into assembling the evidence into an accurate timeline, modeling the towers, modeling the effect of the impact, modeling the fires and then putting all that together to see the global impact of all these forces on the overall structure.
This much more extensive investigation that NIST carried out corrected a number of speculative errors that were in the FEMA report.
Arthur
PS That comment about the TNYTs was actually just a little Global Warming humor as the TNYT's often seems to get the facts about that subject wrong.
QUOTE (adoucette+May 2 2007, 07:27 PM)
David posted a link to a map of the damage to WTC basement.
It appears to be in reasonable aggrement with the LERA analysis.
But the link you followed:
March 29th - Report on Collapse.
The Report that link is talking about was the FEMA report.
As I posted earlier, FEMA thought that the antenna had first started to fall into the tower but it took NIST, with its more extensive Video and time stamped picture library, to determine that this was an illusion caused by the angle the video was taken from.
Arthur
Illusion!?
To reiterate, you and NIST are mistaken about this tilt happening when the antenna began its descent. Look at the NIST pictures you highlighted. The smoke expulsions generated when the block began its descent (and this is when the antenna began its tilt) clearly happened after the antenna had already begun its descent.
This is evident in both the NIST photos and the frame-by-frame video analysis.
NIST NCSTAR 1-6 Sect 6-2 WTC 1 Structural observations, Fig 6-7, 6-9 and 6-11
Frame-by-frame:
http://911research.wtc7.net/wtc/evidence/v...ose_frames.html
BUT HE SAID
ON THE CONTRARY
BLESSED ARE THOSE WHO HEAR THE WORD OF GOD AND OBSERVE IT
It appears to be in reasonable aggrement with the LERA analysis.
But the link you followed:
March 29th - Report on Collapse.
The Report that link is talking about was the FEMA report.
As I posted earlier, FEMA thought that the antenna had first started to fall into the tower but it took NIST, with its more extensive Video and time stamped picture library, to determine that this was an illusion caused by the angle the video was taken from.
Arthur
Illusion!?
To reiterate, you and NIST are mistaken about this tilt happening when the antenna began its descent. Look at the NIST pictures you highlighted. The smoke expulsions generated when the block began its descent (and this is when the antenna began its tilt) clearly happened after the antenna had already begun its descent.
This is evident in both the NIST photos and the frame-by-frame video analysis.
NIST NCSTAR 1-6 Sect 6-2 WTC 1 Structural observations, Fig 6-7, 6-9 and 6-11
Frame-by-frame:
http://911research.wtc7.net/wtc/evidence/v...ose_frames.html
BUT HE SAID
ON THE CONTRARY
BLESSED ARE THOSE WHO HEAR THE WORD OF GOD AND OBSERVE IT
Arthur,
I know that story of floating floors, in fact vertical domino stones that require an amount of energy E1 to be detached from the core columns and also perimeter columns. I was not talking about the initiation but the collapse itself. It would be nice to visualize this a little bit, it is easy to talk about wedging or funneling of mass but as long as you have no model about that it is a useless discussion. Since we have a symmetrical situation then if A wedges B then B wedges A, we can forgot about the wedge. Funneling is better, but its almost the law of conservation of problems. How would that happen, an intact top block cannot funnel into the perimeter columns because that top block also still has perimeter and inner core columns, almost like you cut a piece of coax cable. A uniform non-tilting
E1 model would be a good explanation (if you modify it with some crush-up in the beginning), because if you believe in the stepwise absorption of an amount of E1.
I don’t believe that a tilt leads to a totally different progressive collapse than a no-tilting model because of the coax-structure of the building. Sometimes I think that people here say it is crucial for the global collapse to start with a tilting block. Is that because plastic waves can travel easily or is there an other reason? Even with a non-tilting block the ejection of perimeter columns could be explained by fracturing of perimeter columns, like spaghetti, but only in the E1 way.
ps. The NIST spokesman really said the core failed first, this will make the story even more difficult.
I know that story of floating floors, in fact vertical domino stones that require an amount of energy E1 to be detached from the core columns and also perimeter columns. I was not talking about the initiation but the collapse itself. It would be nice to visualize this a little bit, it is easy to talk about wedging or funneling of mass but as long as you have no model about that it is a useless discussion. Since we have a symmetrical situation then if A wedges B then B wedges A, we can forgot about the wedge. Funneling is better, but its almost the law of conservation of problems. How would that happen, an intact top block cannot funnel into the perimeter columns because that top block also still has perimeter and inner core columns, almost like you cut a piece of coax cable. A uniform non-tilting
E1 model would be a good explanation (if you modify it with some crush-up in the beginning), because if you believe in the stepwise absorption of an amount of E1.
I don’t believe that a tilt leads to a totally different progressive collapse than a no-tilting model because of the coax-structure of the building. Sometimes I think that people here say it is crucial for the global collapse to start with a tilting block. Is that because plastic waves can travel easily or is there an other reason? Even with a non-tilting block the ejection of perimeter columns could be explained by fracturing of perimeter columns, like spaghetti, but only in the E1 way.
ps. The NIST spokesman really said the core failed first, this will make the story even more difficult.
PhysOrg scientific forums are totally dedicated to science, physics, and technology. Besides topical forums such as nanotechnology, quantum physics, silicon and III-V technology, applied physics, materials, space and others, you can also join our news and publications discussions. We also provide an off-topic forum category. If you need specific help on a scientific problem or have a question related to physics or technology, visit the PhysOrg Forums. Here you’ll find experts from various fields online every day.
To quit out of "lo-fi" mode and return to the regular forums, please click here.