Science fail: NIST physics tells us resistance is only mental?

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jas
Science fail: NIST physics tells us resistance is only mental?

So far we have established that cars cannot drive through brick walls at the same speed as if they were driving through an open gate. (See Can a car drive through a brick wall...) and that their momentum will be slowed by the impact of the brick wall. This demonstrates our understanding that the movement or acceleration of objects meeting other objects in their path will be altered in some way, slowed or halted altogether.

There seems to be still some debate here, though, that gravitational pull is much more powerful than anything that might be propelled by an engine. There seems to still be a belief, still unsupported by any known scientific principle, that gravity can pull objects through other objects of equal or greater density at the rate or near the rate that it will pull an object through air.

Just in case anyone here doesn't understand the argument being presented: the official explanation offered by NIST and promoted in popular media for the collapse of the Twin Towers (and WTC7) is that the upper floors of the towers, above where the planes crashed, crushed through the remaining intact building below the fire zones at a speed which is evidenced in all video footage to be at the rate of free fall, or within seconds of it.

Various arguments that have been presented here at Babble or in official story venues to explain what is not explainable by any known scientific principle include:

  1. the speed of collapse was “nowhere near” free fall, being up to four seconds longer than free fall. This argument, in essence, asks us to believe that 91 and 78 floors respectively of the Twin Towers produced only 1- 4 seconds of resistance to the descending upper mass of floors. This argument also cannot explain at what point this descending mass of floors was pulverized in its descent (as there is no visual evidence of any significant pancaking having occurred). Was it on the way down, or did it get “crushed up” at the bottom, as the “crush down, crush up” theory suggests?

  2. If it is the latter, then the “crush down, crush up” theory asks us to suspend our disbelief in the possibility of these descending blocks of floors to maintain their mass while pulverizing 91 or 78 levels of intact building (at the rate it would take for a brick to drop the same distance through air), and only at the bottom would it be pulverized in meeting the ground, but actually not even then, as we know that the buildings collapsed into their basements.

  3. That fires caused the structural weakening that allowed all three buildings to disintegrate in a manner that professional demolitioners compare to controlled demolitions. The fire theory is also NIST's best explanation for the collapses, despite FEMA's earlier suggestion that this theory only had a “low probability” of being correct. The pancake fire theory suggested that the joints which held the trusses (which held the floors) to the core columns through the entire height of the buildings were all weakened by the upper floor fires, which, in the Twin Towers, lasted less than 90 and 60 minutes respectively. And furthermore, that these joints which held the floors to the columns all disassembled themselves simultaneously, so as to create the global lack of resistance that we witnessed in the video footage of the collapses. This theory is not supported by NIST and haas in any case been debunked. The NIST fire theory talks vaguely and briefly about floors sagging and pulling in the perimeter columns, which stress the core columns and vice versa. No one has seen NIST's computer modelling of this hypothesis and many doubt it (eg; article in New Civil Engineer) Whatever fire theory is used does not explain the disintegration of the building's core, which, by its design, would not collapse or disintegrate the way theoretically pancaking/crushing floors would.

These are the main arguments that still remain to explain the never-before-witnessed-in-history rapid disintegration of three, modern, steel-mesh-frame skyscrapers. If I have missed any significant argument here, please feel free to correct me.

I would like to use this thread to examine these specific arguments and also, hopefully, to investigate why people who invoke science and scientific empiricism in other topics of hot debate seem so willing to avoid any serious, plain-language, eyes-open look into the absence of science in their arguments on this subject. We have yet to see anyone here on Babble confirm for us what principle of physics explains the lack of resistance we witness in the rapid disintegration of the towers. (Shouldn't this be easy if the official explanation is so “obvious”?) The only principle that we know about is that for a building (let alone three) to disintegrate in that manner and at that speed can only mean that the bulk of the building presented no resistance to its own descent; in other words, something else was used to remove that resistance. In controlled demolition, it is explosives. What was it in the case of the WTC?

Pants-of-dog

Is there evidence that the towers fell that quickly? All the videos that I have seen have been somewhat bereft of anything that can gives us a good indication of the velocity and acceleration of the towers as they fell.

Tommy_Paine

 

A speed which will never match the movements of truther's goal posts.

Fidel

[url=http://world911truth.org/60-aerospace-engineers-call-for-a-new-911-inves... Aerospace Engineers Call for a New 9/11 Investigation[/url]

Quote:
"When I was confronted with the facts, and I considered the reality that the temperatures of jet fuel combustion do not support the suggested failure modes posed by the government’s official report, I was forced into a paradigm shift. This reality has changed my entire perspective on the groups that I had previously dismissed as emotional, uneducated fools. I was wrong and I am grateful to the 9/11 Truthers for holding me accountable for the Truth! Now, I too am a 9/11 Truther." -- Phil R. Bales, Aerospace Reliability and Life-Cycle Engineer. Employers have included major commercial engine companies, Teledyne CAE, Raytheon, and US Navy Civil Service.

 

Jingles

You should read up on avalanches, Jas. There's this phenomenon wherein many tonnes of rock, unconsolidated, will behave like a liquid when flowing downhill as a mass. 

Fidel

And therefore we can only conclude that: 1. Governments or government subgroups don't perpetrate false flag, and

2. All those engineers and architects with a combined 25000 years of experience, and all those aerospace engineers, pilots, lawyers and intellectuals for truth are wrong about 9/11. Cuz crazy George had an investigashun. An never mind whut those commishners said about it bein a whitewash and cover up.

3. Crazy George's people weren't influencing publicly funded agencies wrt climate science denial either.

Darned hippie peaceniks anyway. Whada they know? Anyway?

 

jas

What is this thing with avalanches? Do you not understand the difference between matter that moves laterally across paths of least resistance, and matter that moves vertically through the path of greatest resistance? There is no comparison. Buildings are not avalanches, folks. OK? Unless they've been pulverized by some force and sent running down mountainsides. If you want to argue that the WTC towers' destruction, the descent of that pulverized material, resembled avalanches, I agree with you. The question is: what caused that pulverisation? Buildings don't do that to themselves.

jas

Tommy_Paine wrote:

A speed which will never match the movements of truther's goal posts.

If you could elaborate on this, that would be great. Last time I checked, you guys don't even have any arguments left, so what goal posts would we need to move, and for what purpose? I don't necessarily want to get into a pissing match about this, but I've noticed this is a new meme in the deniers' arguments.

In fact, it's the opposite. In the early years of 9/11 skepticism, deniers always asked for the evidence. Now that the evidence is not only abundant but researched and sourced, deniers suddenly don't want to look at it. They don't want to read the articles. They don't want to discuss scientific validity. They don't want to discuss accepted principles of physics. What they do is pull in all the ridiculous arguments that they can find to discredit the legitimate research. (I'm doing a bit of reading right now on some of the disinformation campaigns in the 9/11 debate). In short, it is deniers who are moving the goal posts.

Fidel

According to the pro-guvmint splanation , a falling mass always takes the path of most resistance at near free fall rate of descent. It says so right there in Fig Newton's manual of fizzics entitled: Bush Guvmint Science fer dummies.

Pants-of-dog

So, I did a google search, and I was unable to find any evidence that the WTC towers collapsed at terminal velocity.

500_Apples

Pants-of-dog wrote:

So, I did a google search, and I was unable to find any evidence that the WTC towers collapsed at terminal velocity.

Terminal velocity for 400 meters?

9.03 seconds.

I don't know how long the towers took.

Fidel

And that's in a vacuum, as in without air or any other forces of resistance.

The [url=http://www.9-11commission.gov/report/911Report.pdf]The 9/11 Commission Report(pdf)[/url] states that the south tower collapsed in ten seconds.

 

jrootham

I hate to break it to you, Fidel, but 10 is greater than 9.03.

Fidel

jrootham wrote:
I hate to break it to you, Fidel, but 10 is greater than 9.03.

Jim Hoffman is a scientist who is published in peer reviewed scientific journals. His calculations show that even if the structure itself offered no resistance, or in other words,  even if the 110 floors of each tower were suspended in mid-air, the “pancake” theory would still have taken a minimum of 15.5 seconds to reach the ground.

So  even if the building theoretically didn’t exist and floors were suspended in mid-air - if it provided no resistance at all to the collapse - just the floors falling on each other and causing each other to decelerate - it should have taken ...

It should have taken 15.5 seconds to reach the ground. In fact, the handful of NIST scientists have since switched gears on the very slip-shod FEMA report and going with a brand new bullshit theory concerning instantaneous failure of all steel beams and columns in unison. It's fantastical bullshit. Crazier'n ten barrels of monkey doo when you look at it.

But the handful of fed scientists admit that they still cannot fully explain the collapses of all three buildings in the times that it took.

And then there was visible tilting of the upper floor block of the tower as shown in videos. That fact, says David Griscom, a former research physicist and project manager with DARPA, would have altered force balance calculations considerably, and not in a way that would support crazy, whacky as hell Jorge de la Yeyo's government and their official cover up of just this end of the 9/11 narrative. And there was a lot more grinning chimp business concerning who the highjackers were and their connections to US Military and FBI since the CIA's anticommunist jihad against communism in 1980s Central Asia and continuing today in the form of destabilization efforts of those countries.

Fidel

Quote:
How can 80+ strongest, undamaged and heaviest bottom floors offer only 0.78 seconds of resistance between them – yet were designed and built to withstand 3 times working load and have “indestructible cores” when new. This is without considering air resistance and any other slowing effect.

“This simple maths proves 911 was a demolition” -- John A. Blacker, MSc IMI (Physical Systems)

seena

i seriously adore your posting way, very helpful, don't quit and also mcse questions keep creating for the reason that it just worth to read it,excited to find out pleasant day way more of your own content articles, have a nice day!

[Link deleted by Maysie and the poster is banned]

Pants-of-dog

Fidel wrote:

And that's in a vacuum, as in without air or any other forces of resistance.

The [url=http://www.9-11commission.gov/report/911Report.pdf]The 9/11 Commission Report(pdf)[/url] states that the south tower collapsed in ten seconds.

The report is wrong.

http://www.debunking911.com/freefall.htm

 


 

Fidel wrote:

Jim Hoffman is a scientist who is published in peer reviewed scientific journals. His calculations show that even if the structure itself offered no resistance, or in other words,  even if the 110 floors of each tower were suspended in mid-air, the “pancake” theory would still have taken a minimum of 15.5 seconds to reach the ground.

So  even if the building theoretically didn’t exist and floors were suspended in mid-air - if it provided no resistance at all to the collapse - just the floors falling on each other and causing each other to decelerate - it should have taken ...

It should have taken 15.5 seconds to reach the ground. In fact, the handful of NIST scientists have since switched gears on the very slip-shod FEMA report and going with a brand new bullshit theory concerning instantaneous failure of all steel beams and columns in unison. It's fantastical bullshit. Crazier'n ten barrels of monkey doo when you look at it.

But the handful of fed scientists admit that they still cannot fully explain the collapses of all three buildings in the times that it took.

And then there was visible tilting of the upper floor block of the tower as shown in videos. That fact, says David Griscom, a former research physicist and project manager with DARPA, would have altered force balance calculations considerably, and not in a way that would support crazy, whacky as hell Jorge de la Yeyo's government and their official cover up of just this end of the 9/11 narrative. And there was a lot more grinning chimp business concerning who the highjackers were and their connections to US Military and FBI since the CIA's anticommunist jihad against communism in 1980s Central Asia and continuing today in the form of destabilization efforts of those countries.

http://www.garlicandgrass.org/issue6/Dave_Heller.cfm

Your first paragraph is incredibly similar to one of the paragraphs on this site. I suggest linking to sources if you are going to quote or even paraphrase them.

The site by Dave Heller has some factual inaccuracies. For example, it suggests that steel needs to melt before losing structural strength. This is not the case. Steel will lose most of its structural strength long before it reaches its melting point.



Spectrum wrote:

(please see the photos atth estart of Spectrum's post.

In both of these photos we can clearly see columns falling faster than the debris cloud, which in turn is falling faster than the main section tha tconstitutes the top floors. If the WTC had actually fallen at terminal velocity, or close to it, we would see the columns, the debris cloud, and the main section all falling at the same rate.


Fidel wrote:

Quote:
"How can 80+ strongest, undamaged and heaviest bottom floors offer only 0.78 seconds of resistance between them - yet were designed and built to withstand 3 times working load and have "indestructible cores" when new. This is without considering air resistance and any other slowing effect.

"This simple maths proves 911 was a demolition" -- John A. Blacker, MSc IMI (Physical Systems)

Because the working load that the WTC was designed to withstand is a static load, not a dynamic load. Moreover, the weight that each floor had to withstand was the total weight of all the floors above the impact zone. The dynamic weight of almost a third of the building is much higher than three times the normal static occupancy load.

jas

Pants-of-dog wrote:

The report is wrong.

http://www.debunking911.com/freefall.htm


NIST confirms free fall, pants. All video footage confirms free fall or within seconds of free fall.

Debunking911 is a joke site.

But if you're quite convinced, tell us: how long did the towers take to collapse?

jas

Fidel, someone seriously adores your posting way.

What about my posting way? Why doesn't someone seriously adore me?

mmphosis
Fidel

Jas, that person hasn't read your posts is all I can say. The truth isn't out there some where. It's right here in this thread!

Pants-of-dog wrote:
Because the working load that the WTC was designed to withstand is a static load, not a dynamic load. Moreover, the weight that each floor had to withstand was the total weight of all the floors above the impact zone. The dynamic weight of almost a third of the building is much higher than three times the normal static occupancy load.

Yes, and [url=http://www.counterpunch.org/physic11282006.html]Dr. Manuel Garcia[/url] calculated that the total force(static+dynamic) exerted by the upper block on the lower at time of impact to be 6.1 times the weight of the upper block.  [url=http://journalof911studies.com/letters/e/hand-waving-the%20physics-of-91... Griscom, PhD Physics[/url](pdf), however says that not only is Garcia's number for force balance unsupported by Garcia's own calculations, the figure of 6.1 X's is highly unlikely to have caused total instantaneous collpase of the massive steel structure below the descending block 3 metres below.

And not when the lower block's steel columns at the periphery of the building -  which was the weakest part of the building's steel framework - were over-designed to withstand live load increases of up to 2000 percent! This is a factor of 20 not Garcia's 6.1, which in Griscom's expert opinion was surely not even that magnitude on 9/11 given the visible tilting of the upper block just before collapse initiation. Tilting changes force balance equation parameters in a way that lessens the downward force at time of impact. So even Dr. Garica's figure of 6.1 is surely too large a factor.

In fact, the handful of US government scientists have since abandoned their own pancaking theory, and it's because it is so fantastically unbelievable. And we can thank the thousands of A&E truthers and other independent experts who have since forced NIST scientists to back-pedal and back-track on their official conspiracy theory that defies established Newtonian laws of physics.

[url=http://www.dailycommonsense.com/mit-engineer-jeff-king-says-911-official... King (MIT) says official conspiracy theory is impossible[/url] YouTube

Fidel

[url=http://video.google.com/videoplay?docid=-2001897549763616199#]Mind the Gap(YouTube)[/url] Ex-MI5 whistle blower blows whistle on 7/7 false flag terror  (Shayler worked for 'Reds under our beds' MI5 fascists)

Greed and corruption driving global war on democracy

Pants-of-dog

jas wrote:

NIST confirms free fall, pants. All video footage confirms free fall or within seconds of free fall.

Debunking911 is a joke site.

But if you're quite convinced, tell us: how long did the towers take to collapse?

Could you provide a source that confirms that?

 


Fidel wrote:
Yes, and [url=http://www.counterpunch.org/physic11282006.html]Dr. Manuel Garcia[/url] calculated that the total force(static+dynamic) exerted by the upper block on the lower at time of impact to be 6.1 times the weight of the upper block.  [url=http://journalof911studies.com/letters/e/hand-waving-the%20physics-of-91... Griscom, PhD Physics[/url](pdf), however says that not only is Garcia's number for force balance unsupported by Garcia's own calculations, the figure of 6.1 X's is highly unlikely to have caused total instantaneous collpase of the massive steel structure below the descending block 3 metres below.

 

 

And not when the lower block's steel columns at the periphery of the building -  which was the weakest part of the building's steel framework - were over-designed to withstand live load increases of up to 2000 percent! This is a factor of 20 not Garcia's 6.1, which in Griscom's expert opinion was surely not even that magnitude on 9/11 given the visible tilting of the upper block just before collapse initiation. Tilting changes force balance equation parameters in a way that lessens the downward force at time of impact. So even Dr. Garica's figure of 6.1 is surely too large a factor.

 

In fact, the handful of US government scientists have since abandoned their own pancaking theory, and it's because it is so fantastically unbelievable. And we can thank the thousands of A&E truthers and other independent experts who have since forced NIST scientists to back-pedal and back-track on their official conspiracy theory that defies established Newtonian laws of physics.

 

[url=http://www.dailycommonsense.com/mit-engineer-jeff-king-says-911-official... King (MIT) says official conspiracy theory is impossible[/url] YouTube

 

 

Dr. Garcia does not claim at any point that there was a "total instantaneous collpase of the massive steel structure."

As for your figure of 2000%, that is in comparison to the designed load, or the typical load for a single floor. That means it was designed to take twenty times the normal load of people and filing cabinets of a single floor. This is still far far smaller than 6.1 times the weight of the top ten or twenty floors of one of these buildings. And i don't think that lateral motion has an impact on the kinetic energy from gravity. A bullet shot from a gun will descend to the ground at the same speed and with the same downward energy as a bullet dropped at the exact same time. Dr. Griscomb's assumptions in this regard are faulty, as his criticisms of Garcia's work depend on a the object deforming itself at the time of impact. If the object does not deform, then the impact (i.e. the time it takes for th eforce to transfer) would be minimal as Garcia suggested.

As for your final link, I don't have a sound card.

 

I would like to repeat that Spectrum's photos upthread clearly show columns falling faster than the debris cloud, which in turn is falling faster than the large titlting block.

Fidel

Pants-of-dog wrote:
Dr. Garcia does not claim at any point that there was a "total instantaneous collpase of the massive steel structure."

I'm afraid he does.  In one one-hundredth of a second, according to Garcia's calculus, all of the 47 massive steel inner core columns and 200 outer support beams snapped like twigs under a downward force that was 6.1 times the weight of the descending upper block. And the failure was not only instantaneous but simultaneous, and within 1/100 of a second. As impossible as that sounds to Griscom, and Garcia does not identify how he arrives at his figure for duration of impact of 0.01 seconds, Griscom says this assumption is critical to Garcia's thesis for total downward force balance of 6.1 times the weight of the upper block of floors(static plus dynamic) against the lower block after a 3 metre descent(and assuming zero air resistance and zero resistance by the massive steel support structure).

Griscom says the odds against all 250 massive steel columns and outer support beams failing under different conditions of temperature and stress and all in unison within a time that was much shorter than a blink of an eye must be astronomical. It's fantastically unbelievable for those who understand what Garcia is trying to prove by intimidation more than anything.

Pants-of-dog wrote:
As for your figure of 2000%, that is in comparison to the designed load, or the typical load for a single floor. That means it was designed to take twenty times the normal load of people and filing cabinets of a single floor. This is still far far smaller than 6.1 times the weight of the top ten or twenty floors of one of these buildings.

I don't think so. The 2000 per-cent refers to live loading of just the 200 outer support beams at the periphery, which were the weakest points of the steel structure. Garcia assumes several things which are unsupported by either his own calculus or Newtonian laws of physics. As Griscom says, any tilting of the upper block of floors by even one degree, and the tilting was visible from video footage, changes the calculation for force balance to a lesser order of magnitude not greater.

But by dr Garcia's calculus, the downward force wasn't even 2000 per-cent. And by Griscom's estimation, it wasn't even 600% of the weight of the descending block of floors.

In fact, no one is actually arguing that collapse did not occur. What's being argued is the collapse initiation theory or how fast the support beams and columns gave way to the descending upper block. Arguments like Garcia's assume that the massive steel support structure provided zero resistance against the descending upper block over 3m and assuming no air resistance.

jrootham

Given that crack propagation is at the speed of sound, I am not surprised at minimal delays by heavily overloaded floors.

BTW, what is the difference in appearance between pancake collapse and demolition?

 

Fidel

jrootham wrote:
BTW, what is the difference in appearance between pancake collapse and demolition?

I think Ockham would suggest going with an explanation that requires the least number of assumptions. Pancake requires more assumptions and ignoring eye witness clues, and smoothing over certain evidence from video taped footage of the events.

I'm thinkin' demolition.  And not all based on fancy guesstimations resulting in near free-fall rate of collapse that don't add up. Griscom believes that a supercomputer is needed to properly corner and check the proof by intimidation side.

 Some of my fear that it was false flag is gut instinct based on the Gladio Gang's notorious record which precedes them. What were the odds that a country whose economy is largely based on war would have a valid pretext for war fall into their laps the way 9/11 unfolded? All of the timings were too perfect from start to finish. It's said that errant planes are met with air force fighter jets and escorted out of harm's way, and within 20-25 minutes or so, about a hundred times a year. And yet on 9/11, two amateur Cessna pilots dominated NORAD air space for almost two hours?

 

jrootham

 

That wasn't an answer to my question.

 

But this whole thing is delusional beyond belief.

 

I will attempt to revert to ignoring it.

 

Fidel

Ya whatever, And don't forget, 9.03 is practically 10. And 10 isn't that far from 15. Brutal.

jas

All these silly assertions and still no one answers the question. Just more sock puppets and defenders of bizarre stories and fake science.

I think I'll stick with what the people who were actually there say, and what the people who know something about building design and mechanics say.  

jrootham

That would be the NIST.

 

Fidel

NIST is a laughing stock for more than one-thousand A&Es for truth, and who combined possess more than 25,000 years of experience. They aren't hippies protesting in front of the Pentergone and holding up "Stop this phony war" signs.

jrootham

They are dumber than that.

 

Pants-of-dog

Fidel wrote:

I'm afraid he does.  In one one-hundredth of a second, according to Garcia's calculus, all of the 47 massive steel inner core columns and 200 outer support beams snapped like twigs under a downward force that was 6.1 times the weight of the descending upper block. And the failure was not only instantaneous but simultaneous, and within 1/100 of a second. As impossible as that sounds to Griscom, and Garcia does not identify how he arrives at his figure for duration of impact of 0.01 seconds, Griscom says this assumption is critical to Garcia's thesis for total downward force balance of 6.1 times the weight of the upper block of floors(static plus dynamic) against the lower block after a 3 metre descent(and assuming zero air resistance and zero resistance by the massive steel support structure).

Griscom says the odds against all 250 massive steel columns and outer support beams failing under different conditions of temperature and stress and all in unison within a time that was much shorter than a blink of an eye must be astronomical. It's fantastically unbelievable for those who understand what Garcia is trying to prove by intimidation more than anything.

I'm sorry, but you are reading Dr. Garcia's work incorrectly. 1/100th of a second was the duration of the impact, not the the duration of the collapse. Nor would it be necessary for the entire structure to collapse simultaneously. As long as the weakest points (such as the joints between structural members) failed, the rest of the structure could be intact, but it would still be unable to support the load.

Fidel wrote:

I don't think so. The 2000 per-cent refers to live loading of just the 200 outer support beams at the periphery, which were the weakest points of the steel structure. Garcia assumes several things which are unsupported by either his own calculus or Newtonian laws of physics. As Griscom says, any tilting of the upper block of floors by even one degree, and the tilting was visible from video footage, changes the calculation for force balance to a lesser order of magnitude not greater.

But by dr Garcia's calculus, the downward force wasn't even 2000 per-cent. And by Griscom's estimation, it wasn't even 600% of the weight of the descending block of floors.

I should be more clear: the safety margin of 2000% means that the 200 outer steel support beams at the perihpery were designed to withstand 20 times the normal load. The normal load for each floor is the expected amount of people and furniture and wind and dead load of building for that one floor.

When Garcia is discussing the 6.1, he is saying that the force which with the upper block hit each floor was equivalent to 6.1 times the weight of the upper block.

Now, obviously the weight of the entire upper block is far higher than the expected weight for a single floor. So, you can not compare them on a one to one basis.

Fidel wrote:
In fact, no one is actually arguing that collapse did not occur. What's being argued is the collapse initiation theory or how fast the support beams and columns gave way to the descending upper block. Arguments like Garcia's assume that the massive steel support structure provided zero resistance against the descending upper block over 3m and assuming no air resistance.

Garcia does not assume that the lower floors provided zero resistance. I will quote from the article of his to which you linked (bolding mine for emphasis):

"Here, positive direction, velocity and force are taken to be vertically upward; dt is a label for "delta t", a very brief time interval during which the impact occurs and the momentum changes from m*v(initial) to m*v(final); and F is the force of resistance by the lower structure. If A is the net horizontal cross-sectional area of the load-bearing columns of the lower structure, then F/A is the average compressive stress across that area."

Fidel

Pants-of-dog wrote:

Fidel wrote:
... As impossible as that sounds to Griscom, and Garcia does not identify how he arrives at his figure for duration of impact of 0.01 seconds,

I'm sorry, but you are reading Dr. Garcia's work incorrectly. 1/100th of a second was the duration of the impact, not the the duration of the collapse.

Okay then, have it your way.

Pants-of-doag wrote:
I should be more clear: the safety margin of 2000% means that the 200 outer steel support beams at the perihpery were designed to withstand 20 times the normal load. The normal load for each floor is the expected amount of people and furniture and wind and dead load of building for that one floor.

Okay, but concerning that floor at the top of the lower block - the floor of the south tower which was impacted - what were that floor's outer steel beams and columns holding up against a (negative) force balance since the building of the WTC? Obviously the upper block was part of the live load all those years and negative force balance distributed throughout the massive steel structure below it.

Pants-of-dog wrote:
When Garcia is discussing the 6.1, he is saying that the force which with the upper block hit each floor was equivalent to 6.1 times the weight of the upper block.

Absolutely not. No. Garcia is talking about the total force balance of the upper block impacting the lower after a descent of 3 metres only. He's not talking about the total force applied against any of the lower floors below the specific floor of interest. He's talking about collapse initiation and nothing of the events after that.

Pants-of-dog

Fidel wrote:

Okay, but concerning that floor at the top of the lower block - the floor of the south tower which was impacted - what were that floor's outer steel beams and columns holding up against a (negative) force balance since the building of the WTC? Obviously the upper block was part of the live load all those years and negative force balance distributed throughout the massive steel structure below it.

The beams hold up the weight of each floor. The columns hold up the beams and the floors above. So, the columns could have conceivably held up the entire WTC, except that they had been sheared by the impact of the plane. When the upper block impacted on the floor below, the force of the impact sheared the joints between the beams and the columns. These joints would not only be unable to hold up the floor anymore, but they would also be unable to brace the columns against lateral movement anymore, which wold inevitably result in buckling.

Fidel wrote:

Absolutely not. No. Garcia is talking about the total force balance of the upper block impacting the lower after a descent of 3 metres only. He's not talking about the total force applied against any of the lower floors below the specific floor of interest. He's talking about collapse initiation and nothing of the events after that.

I understand that. The point I am making is that the 6.1 times is referring to the weight of the entire upper block, while the 2000% refers to the weight of a single floor.

jas

Quote:
As documented in Section 6.14.4 of NIST NCSTAR 1, these collapse times show that:

...Since the stories below the level of collapse initiation provided little resistance to the tremendous energy released by the falling building mass, the building section above came down essentially in free fall, as seen in videos. As the stories below sequentially failed, the falling mass increased, further increasing the demand on the floors below, which were unable to arrest the moving mass.”

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

jas
Fidel

I don't agree with anything in Pants-of-dog's reply to me in paragraph one. You're essentially ignoring everything Griscom said wrt Garcia's proof by intimidation.

The 2000 figure refers to an engineering over-design of 2000 per-cent in live load with respect to the 200 outer beams and columns at the periphery only. Those 200 outer beams and columns working in tandem with the 47 massive steel inner core columns at each floor were designed to hold up everything above it since construction in the 1960s.

In fact, Dave Griscom is saying that live load was not close to having increased by 2000 per-cent at the moment of impact. It probably wasn't even close to 6.1 times the weight of the upper block referred to loosely by Dr. Garcia.

In his essay, [url=http://911review.com/articles/ryan/lies_about_wtc.html]Propping up the War on Terror[/url]:

Kevin Ryan wrote:
NIST claimed the perimeter columns saw increased loads of between 0 and 25% due to the damage, but it never reconciled this with the original claim that these columns could resist 2000% increases in live load.

And no one knows how Dr. Garcia arrives at his dt=0.01 seconds leading to a 6.1 times weight of the upper block increase. He doesn't say.

jas

Fidel wrote:

I don't agree with anything in Pants-of-dog's reply to me in paragraph one. You're essentially ignoring everything Griscom said wrt Garcia's proof by intimidation.

I actually understand very little of what he is trying to say. He seems to think that one floor collapsing inevitably leads to all floors collapsing. Even if this were true, which 1,200 architects and engineers here claim can't be, that kind of successive floor collapse cannot occur within the timeline that we witnessed. It cannot even occur in several minutes without that resistance being removed in some prior fashion.

I don't understand what's so difficult for some to grasp about this.

If all you need to do to bring down a highrise structure is take out a few upper floor columns, why don't professional demolitioners employ this technique??

This is getting stupid.

Fidel

They don't want to consider what more than one-thousand independent professionals have had to say on the matter. Their minds were made up after the official conspiracy report was published - a commission of panelists who did not convene until 444 days after the false flag terror attack. And then the report itself wasn't made public until 2004.

The Commission did state that neither US cosmetic government of Clinton or Bush II were well served by the CIA or FBI. And those two agencies are at the centre of serious accusations by several government whistle blowers including Sibel Edmonds.

Instead, non-truthers defer us to a handful of government scientists who were under duress of losing their jobs and pensions under crazy George II's government, who were also complicit in climate science denial as well as the official 9/11 conspiracy theory. It was a decade of bad, US Government-sponsored science in general.

Pants-of-dog

Fidel wrote:

The 2000 figure refers to an engineering over-design of 2000 per-cent in live load with respect to the 200 outer beams and columns at the periphery only. Those 200 outer beams and columns working in tandem with the 47 massive steel inner core columns at each floor were designed to hold up everything above it since construction in the 1960s.

Columns support the floors above. Beams support only the one floor of which they are a part. The only role the perimeter beams played in supporting upper floors was to brace the columns against lateral  (sideways) movement.

Fidel wrote:
In fact, Dave Griscom is saying that live load was not close to having increased by 2000 per-cent at the moment of impact. It probably wasn't even close to 6.1 times the weight of the upper block referred to loosely by Dr. Garcia.

Can you please quote the relevant text?

Fidel wrote:
And no one knows how Dr. Garcia arrives at his dt=0.01 seconds leading to a 6.1 times weight of the upper block increase. He doesn't say.

An impact, by definition, occurs over a short time scale. http://en.wikipedia.org/wiki/Impact_%28mechanics%29

Pants-of-dog

jas wrote:

I actually understand very little of what he is trying to say. He seems to think that one floor collapsing inevitably leads to all floors collapsing.

Not at all. I am saying that the built in safety margins for the beams has nothing to do with the weight imposed on the columns.

jas wrote:
Even if this were true, which 1,200 architects and engineers here claim can't be, that kind of successive floor collapse cannot occur within the timeline that we witnessed. It cannot even occur in several minutes without that resistance being removed in some prior fashion.

Having a large number of people believing something does not constitute evidence for its veracity. At one point everyone on the Earth believed that the Sun went around the Earth. The popularity of this belief did not make it true.

jas wrote:
I don't understand what's so difficult for some to grasp about this.

If all you need to do to bring down a highrise structure is take out a few upper floor columns, why don't professional demolitioners employ this technique??

Because it is incedibly unsafe.

Fidel

Pants-of-dog wrote:

Fidel wrote:

The 2000 figure refers to an engineering over-design of 2000 per-cent in live load with respect to the 200 outer beams and columns at the periphery only. Those 200 outer beams and columns working in tandem with the 47 massive steel inner core columns at each floor were designed to hold up everything above it since construction in the 1960s.

Columns support the floors above. Beams support only the one floor of which they are a part. The only role the perimeter beams played in supporting upper floors was to brace the columns against lateral  (sideways) movement.

And there were 200 columns at the periphery of each floor and over-designed to support a 2000% increase in live loads before failure occurs. In fact, NIST has even acknowledged that those beams probably should have withstood even greater negative forces for brief amounts of time.

Pants-of-dog wrote:
Fidel wrote:
In fact, Dave Griscom is saying that live load was not close to having increased by 2000 per-cent at the moment of impact. It probably wasn't even close to 6.1 times the weight of the upper block referred to loosely by Dr. Garcia.

Can you please quote the relevant text?

It's all there in Griscom's essay linked to above. Griscom points out that Garcia's figure of 6.1 isn't even in agreement with NIST findings. Just one degree of tilting would increase Garcia's guesstimate of duration of impact=0.01 second to 0.14 seconds, dt = 0.14 second:

 

Griscom wrote:
giving the instantaneous total force of the falling “upper block” on the lower structure of just 1.3 times the static weight of the “upper block” instead of the 6.1 times as estimated in his “example.”

And he goes on to say that NIST has acknowledged tilting of the upper floor block due to failure of the south and east walls of WTC1&2 above the impacted floors. One video shows tilting by as much as 23 degrees of the upper floor block of WTC2 before collapse.

Pants-of-dog wrote:
An impact, by definition, occurs over a short time scale.
">http://en.wikipedia.org/wiki/Impact_%28mechanics%29

And so how does Dr Garcia arrive at dt = 0.01 second?  That's the $64,000 dollar question. The duration of collapse was likely even longer than 0.14 second and producing an even smaller number for total force of the upper block impacting the upper most floor of the lower block.

jas

Pants-of-dog wrote:

Not at all. I am saying that the built in safety margins for the beams has nothing to do with the weight imposed on the columns.

What does this mean? What happened to the beams in the collapses, pants?

Quote:
Having a large number of people believing something does not constitute evidence for its veracity. At one point everyone on the Earth believed that the Sun went around the Earth. The popularity of this belief did not make it true.

Otherwise known as "This many people can't be that stupid!" ?

Fidel

Before 9/11, before operations mongoose and northwoods, and before Himmler's "operation Himmler" at Gleiwitz, there was imperial Japan's [url=http://en.wikipedia.org/wiki/Mukden_Incident]Mukden false flag incident[/url] of the 1930s. Fascists are all alike when it comes to dirty tricks ending in mass murder.

Fidel

jas wrote:
What does this mean? What happened to the beams in the collapses, pants?

One engineer said he observed partially vaporized beams as well as pools of molten steel in the ground zero rubble. Eye witness testimonials were essentially ignored by NIST and crazy George II's official conspiracy theorists.

jas

Fidel, everyone knows that that piece of steel officially doesn't exist. NIST certainly didn't study it, because it doesn't exist. Well, except for in the back of the FEMA report.

jas

Anyway, I'm really interested in hearing about the beams vs. the columns, and how this, finally, will explain the immediate, simultaneous, and total loss of resistance that occurred in 90 and 78 floors of steel and concrete highrise.

Pants-of-dog

Fidel wrote:

And there were 200 columns at the periphery of each floor and over-designed to support a 2000% increase in live loads before failure occurs. In fact, NIST has even acknowledged that those beams probably should have withstood even greater negative forces for brief amounts of time.

That may be, but the falling upper block of the WTC fell on the structure supported by the beams, not the columns.

Fidel wrote:
It's all there in Griscom's essay linked to above. Griscom points out that Garcia's figure of 6.1 isn't even in agreement with NIST findings. Just one degree of tilting would increase Garcia's guesstimate of duration of impact=0.01 second to 0.14 seconds, dt = 0.14 second:

 

Griscom wrote:
giving the instantaneous total force of the falling “upper block” on the lower structure of just 1.3 times the static weight of the “upper block” instead of the 6.1 times as estimated in his “example.”

And he goes on to say that NIST has acknowledged tilting of the upper floor block due to failure of the south and east walls of WTC1&2 above the impacted floors. One video shows tilting by as much as 23 degrees of the upper floor block of WTC2 before collapse.

And so how does Dr Garcia arrive at dt = 0.01 second?  That's the $64,000 dollar question. The duration of collapse was likely even longer than 0.14 second and producing an even smaller number for total force of the upper block impacting the upper most floor of the lower block.

Here is the entirety of the paragraph from which you copied that quote:

Griscom wrote:
Well, to have such a small value of dt would require that the bottom of the falling “upper
block” meet the floor below without the slightest tilt. For example, accepting Dr. Garcia’s
free-fall speed calculation of 7.7 meters/second, tilting of a 63.4-meters-square WTC
floor by mere 1 degree would increase dt from his guesstimate of dt = 0.01 second all the
way to dt = 0.14 second, giving the instantaneous total force of the falling “upper block”
on the lower structure of just 1.3 times the static weight of the “upper block” instead of
the 6.1 times as estimated in his “example.”

And so how does Dr. Griscom arrive at dt = 0.14 second? That's the $64,000 dollar question. I have no idea. In that respect, he is as uninformative as Dr. Garcia.

The only possible way I can see how tilting would change the duration of the impact would be if the upper block deformed as it hit the floor below.

Think about it this way: Imagine jumping off a height without bending your knees when you land. All your weight will go immediately into the ground the moment your feet hit the floor. This doesn't change if you tuck your legs in and land squarely on your elbow at a fifty degree angle. As long as you hit the ground rigidly, the amount of time it takes for your weight to tranfer to the ground is very short, regardless of how you hit it.

Now, imagine jumping off a height with your body all relaxed and landing in a forward roll. The roll changes the shape of your body as you hit so that your weight is transferred to the ground over a longer time. In this case, the tilting angle does matter. Please note that this is only the case when the body is allowed tochange its shape as it  hits the supporting structure.

Due to the fact that the upper stories of the WTC buildings were rigid structures (i.e. they did not deform or change shape as they hit), we can see how the impact time would not have been affected by tilting.

Pants-of-dog

jas wrote:

What does this mean? What happened to the beams in the collapses, pants?

 

They collapsed, obviously, due to the fact that they were drastically overloaded by the weight of the upper block of stories descending upon them.

jas

Pants, beams are supported by columns, vertical columns.

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