An Analysis of the WTC on 9/11 . . .

reply to post by bsbray11


Did you actually look at the pictures of the steel from the study



or how about this




The above picture was of the floor sagging it had a uniform load of around 5kn/m2 on it
(half a ton for none newton people)

What would have happened if the floors above had dropped as you see in the WTC videos.

This steelwork HAD NO IMPACT DAMAGE FIRST before the fire was set unlike the Towers!!!!!!!

Also have you looked at what the floor trusses were connect to on the wall of the WTC



Those bits of angle NOW compare those to the STEEL BEAMS AND CONECTIONS ABOVE!!!!

Also compare those trusses with this picture



The Empire State Building plane crash, THICKER FLOORS , STEEL SECTION BEAM BUCKLED, LOWER SPEED , LIGHTER MASS, HARDER FACADE do you honestly think those trusses in WTC above would have not been badly damaged by the impacts!!!!

Also how can it be possible for a fire to start in an open plan OFFICE and not spread over the entire floor its not just the fuel that would have burned lets see carpet ,paper,desks, computers etc etc etc. Temperature may not have been intense in all areas thats all!!!

What I said was 100% relevant apples with apples!!!!!

Originally posted by bsbray11
Does such an impact change the physics of what the steel will do when heated, which is the point of these studies in the first place? NO

Yes, it would actually change it. A truss will sag quicker when heated if it has 1000 pounds of weight on it than 500 pounds.

So yes, it will change the way the building reacts. Absolutely. A column under 75% load will fail from inward bowing faster than a column that has only 25% of it's design load.

Originally posted by bsbray11

According to these studies, the hypothesis NIST suggested (and never proved) would not result in the run-away
conditions they suggested it would.

Did you even look at the raw data? Did you even read what the report said? Do you know what "yeild" means?

It means it failed.

Also, does the Cardigan tests use beams instead of trusses? Yes. Do those beams "yeild" due to the heat generated? Yes.

Go look at and READ the ENTIRE report.

This is pretty bad. The fires did not burn long enough or hot enough to cause the trusses to sag enough for them to fall. NIST fudged its data. They found 4" of sag and exaggerated it to over 40" of sag to induce some kind of collapse. Their own studies showed that, of 236 samples tested, 233 had not been exposed to temperatures over 500*F, which is that of an ordinary office fire. THIS IS NIST'S OWN DATA.

The intricate lattice structure of the building created an enormous heat sink drawing heat away from building up at any specific location. Below the 80th floor of the South Tower and the 94th floor of the North, they were stone-cold steel. There was no reason whatsoever for them to collapse. They were designed with a minimum safety factor of 20, which means that, at each level, they could support 20 times their expected live load.

UL certified the steel to 2,000*F for three or four hours without any weakening or melting. That included the trusses. The fires in the South Tower burned for around an hour, in the North for around an hour and a half. SO WE KNOW THE FIRES DID NOT BURN LONG ENOUGH OR HOT ENOUGH TO CAUSE THE STEEL TO WEAKEN, MUCH LESS MELT.

Suppose that the fires had burned hot enough and long enough to cause the steel to weaken, if not melt. Since they were asymmetrically distributed, parts of the affected floors might have sagged or tilted, but not the whole floor, which was not even heated enough. (This whole scenario is contrary to the facts, of course.) So parts of the floor might have sagged or titled.

But it would have been very gradual and partial, not the complete, abrupt, and total demolition that we witnessed. Go back to "New 9/11 Photos Released" at jamesfetzer.blogspot.com... to remind yourself what we are attempting to explain here. NOTHING ABOUT THE DESTRUCTION OF THESE BUILDINGS HAS ANY SIGNS OF COLLAPSE.

The trusses were between the core columns and the external support columns. There were some 200 connections that linked them. For a floor to fall symmetrically, not only would all 200 have to have broken at the same time, but the weight distribution of furniture, computers, bathrooms, cafeterias, and everything else would have had to have been perfectly balanced, lest the truss tilt and become jammed between the columns.

Suppose those extremely improbable conditions had been met. Then one floor would have fallen on another. But since each floor could carry at least 20 times its expected live load, unless that force had exceeded the safety factor, no further collapse would have occurred. And since the fires were asymmetrically distributed in fact, there would only have been some tilting and sagging, not any actual collapse.

None of this is explicable absent the use of powerful explosives. Notice, too, that, if the trusses had fallen, one on another, over and over, down to the ground, then there should have been a stack of trusses that was some 13-14 floors in height. But it didn't happen. And if the trusses fell, the core columns and the support columns would have remained, especially if the collapse had been initiated around 80th and the 94th floors.

Notice, in particular, that the top 30 floors of the South Tower actually tilt and pivot initially, which means that they are not exerting ANY DOWNWARD FORCE AT ALL, EXCEPT AT THE EDGE. And in the North Tower, since there was no reason for the uppermost floors to have fallen first rather than around the 95th, it would have been like emptying a can of tennis balls onto the floor: you still have the upside down can remaining!

And in this case, the sides of the can would be the external support columns and, right in the center of the can, the core columns would remain. But of course the support columns and the core columns were destroyed at the same time as the trusses. SO THERE IS NO EVIDENCE TO SUPPORT ANY COLLAPSE THEORY AT ALL. Get over it. Act like a man. Suck it up. The towers were taken out by a demolition under control. Q.E.D.

reply to post by FDNY343

Originally posted by JimFetzer
This is pretty bad. The fires did not burn long enough or hot enough to cause the trusses to sag enough for them to fall. NIST fudged its data. They found 4" of sag and exaggerated it to over 40" of sag to induce some kind of collapse. Their own studies showed that, of 236 samples tested, 233 had not been exposed to temperatures over 500*F, which is that of an ordinary office fire. THIS IS NIST'S OWN DATA.

kk, maybe you weren't listening. I'll just not care about this.

The intricate lattice structure of the building created an enormous heat sink drawing heat away from building up at any specific location. Below the 80th floor of the South Tower and the 94th floor of the North, they were stone-cold steel. There was no reason whatsoever for them to collapse. They were designed with a minimum safety factor of 20, which means that, at each level, they could support 20 times their expected live load.

Right... you know this because you were inside the building touching the steel and feeling how stone cold it was...

UL certified the steel to 2,000*F for three or four hours without any weakening or melting. That included the trusses. The fires in the South Tower burned for around an hour, in the North for around an hour and a half. SO WE KNOW THE FIRES DID NOT BURN LONG ENOUGH OR HOT ENOUGH TO CAUSE THE STEEL TO WEAKEN, MUCH LESS MELT.

You don't know that for certain. They only needed to weaken the already heavier load bearing steel. NOTHING MELTED OMG. I hate it when you guys insinuate that they melted.

Suppose that the fires had burned hot enough and long enough to cause the steel to weaken, if not melt. Since they were asymmetrically distributed, parts of the affected floors might have sagged or tilted, but not the whole floor, which was not even heated enough. (This whole scenario is contrary to the facts, of course.) So parts of the floor might have sagged or titled.

If part begins sagging, then it puts more weight on the rest, and it eventually domino effects down.

But it would have been very gradual and partial, not the complete, abrupt, and total demolition that we witnessed. Go back to "New 9/11 Photos Released" at jamesfetzer.blogspot.com... to remind yourself what we are attempting to explain here. NOTHING ABOUT THE DESTRUCTION OF THESE BUILDINGS HAS ANY SIGNS OF COLLAPSE.

It was, until the final failure. Then, there was nothing to stop it from collapsing.

The trusses were between the core columns and the external support columns. There were some 200 connections that linked them. For a floor to fall symmetrically, not only would all 200 have to have broken at the same time, but the weight distribution of furniture, computers, bathrooms, cafeterias, and everything else would have had to have been perfectly balanced, lest the truss tilt and become jammed between the columns.

They don't necessarily have to break, just bend. It's during the collapse that they start ripping themselves apart and colliding with the rest of the building to create more kinetic energy to help bring down the towers.

Suppose those extremely improbable conditions had been met. Then one floor would have fallen on another. But since each floor could carry at least 20 times its expected live load, unless that force had exceeded the safety factor, no further collapse would have occurred. And since the fires were asymmetrically distributed in fact, there would only have been some tilting and sagging, not any actual collapse.

I think you're mistaken. The vertical columns were probably meant to withstand 20 times their load, but the horizontal trusses had no such vertical resistance.

None of this is explicable absent the use of powerful explosives. Notice, too, that, if the trusses had fallen, one on another, over and over, down to the ground, then there should have been a stack of trusses that was some 13-14 floors in height. But it didn't happen. And if the trusses fell, the core columns and the support columns would have remained, especially if the collapse had been initiated around 80th and the 94th floors.

Not really. Have you ever played Jenga? Or dropped a bunch of anything on top of itself? They usually bounce around and go to the sides. Anyone watching the tower collapses knows they didn't fall perfectly on each floor. It was asymmetrical overloading on the floors as the debris dropped and crushed down with a great deal of momentum.

Notice, in particular, that the top 30 floors of the South Tower actually tilt and pivot initially, which means that they are not exerting ANY DOWNWARD FORCE AT ALL, EXCEPT AT THE EDGE. And in the North Tower, since there was no reason for the uppermost floors to have fallen first rather than around the 95th, it would have been like emptying a can of tennis balls onto the floor: you still have the upside down can remaining!

Oh, cause this makes a whole lot of sense... So, when it collides with the tower below it, instead of the floors crushing down on the tower below and making it destructively fold into itself with the parts of the undamaged steel holding on (which it did), it should have stopped and just kind of collapsed on the inside only, leaving the panels standing?

And in this case, the sides of the can would be the external support columns and, right in the center of the can, the core columns would remain. But of course the support columns and the core columns were destroyed at the same time as the trusses. SO THERE IS NO EVIDENCE TO SUPPORT ANY COLLAPSE THEORY AT ALL. Get over it. Act like a man. Suck it up. The towers were taken out by a demolition under control. Q.E.D.

Riiight, because the core columns would be completely undamaged from all the debris and destructive force that was able to take out the floors all the way down. Maybe you forgot, but in one tower, part of the core DID survive, but without any other support, it fell in short time. You're digging your own grave man.

There is zero, zip, denada evidence for explosives. Only sounds that were explosive, but not necessarily caused by bombs since exploding concrete and metal hitting metal at high speed can and will make loud booms. And there is evidence of a collapse theory, since they did collapse. That's kind of a fact. You're just disputing how the collapse started and refuse to believe there was enough energy to continue collapsing.

Originally posted by JimFetzer
This is pretty bad.

Your posts usually are, but thanks for the forewarning.

Originally posted by JimFetzer The fires did not burn long enough or hot enough to cause the trusses to sag enough for them to fall. NIST fudged its data. They found 4" of sag and exaggerated it to over 40" of sag to induce some kind of collapse.

Do you have an actual source for this? I seem to recall much less than 40" being cited in the NIST report, but I could be wrong.

Linkey?

Originally posted by JimFetzer Their own studies showed that, of 236 samples tested, 233 had not been exposed to temperatures over 500*F, which is that of an ordinary office fire. THIS IS NIST'S OWN DATA.

Again I ask, where do you get this 500 deg. F. bull**** from? I have asked you to source this claim, and to date, you have yet to do it. I have even cited numerous studies that show this to be wrong, and so has Psychihacker.
(albeit unintentionally)

Maybe you can do so now?

Originally posted by JimFetzer
The intricate lattice structure of the building created an enormous heat sink drawing heat away from building up at any specific location.

I'll ask you as I did psychi; show me the math. Show me how the connections from the trusses to the columns would have transferred enough heat energy to prevent the sagging.

I'll wait.

Originally posted by JimFetzerBelow the 80th floor of the South Tower and the 94th floor of the North, they were stone-cold steel. There was no reason whatsoever for them to collapse. They were designed with a minimum safety factor of 20, which means that, at each level, they could support 20 times their expected live load.

Source for this claim is where? I have seen where the safety factor was (IIRC) around 3. Not 20. Maybe you would like to show where this is shown to be true?

Originally posted by JimFetzer
UL certified the steel to 2,000*F for three or four hours without any weakening or melting.

And again, I ask, where do you get this from? UL would NEVER say "three OR four hours" for anything. THey ALWAYS give a VERY PRECISE measurement. It would be "TWO HOURS" or whatever. Again, please source this claim from UL. NOT Kevin Ryan. He deals with water, not fire.

Originally posted by JimFetzer That included the trusses. The fires in the South Tower burned for around an hour, in the North for around an hour and a half. SO WE KNOW THE FIRES DID NOT BURN LONG ENOUGH OR HOT ENOUGH TO CAUSE THE STEEL TO WEAKEN, MUCH LESS MELT.

Really? The Cardigton tests show that to be inaccurate.

guardian.150m.com...

Thanks to Psychi for posting this for me. It's a great resource. Too bad it doesn't way what you hoped it would.

Originally posted by JimFetzer
Suppose that the fires had burned hot enough and long enough to cause the steel to weaken, if not melt.

They only needed to weaken, not melt. Secondly, there is no doubt that the fire would burn hot enough to cause the steel to fail.

Originally posted by JimFetzer Since they were asymmetrically distributed, parts of the affected floors might have sagged or tilted, but not the whole floor, which was not even heated enough. (This whole scenario is contrary to the facts, of course.) So parts of the floor might have sagged or titled.

And then????? Keep going Jim. What does the sagging floors do?

Originally posted by JimFetzer
But it would have been very gradual and partial, not the complete, abrupt, and total demolition that we witnessed.

The signs of collapse were there. Seen before the collapse.

Would you care to show your math that the lower floor would be able to hold up the higher floors?

Originally posted by JimFetzer Go back to "New 9/11 Photos Released" at jamesfetzer.blogspot.com... to remind yourself what we are attempting to explain here. NOTHING ABOUT THE DESTRUCTION OF THESE BUILDINGS HAS ANY SIGNS OF COLLAPSE.

Really? Do you even know the signs of collapse? I bet you do not, since you keep making this absurd claim.

Originally posted by JimFetzer
The trusses were between the core columns and the external support columns. There were some 200 connections that linked them. For a floor to fall symmetrically, not only would all 200 have to have broken at the same time, but the weight distribution of furniture, computers, bathrooms, cafeterias, and everything else would have had to have been perfectly balanced, lest the truss tilt and become jammed between the columns.

This makes no sense to me whatsoever.

Originally posted by JimFetzer
Suppose those extremely improbable conditions had been met.

Poisoning the well logical fallacy noted, and ignored.

Originally posted by JimFetzer Then one floor would have fallen on another. But since each floor could carry at least 20 times its expected live load, unless that force had exceeded the safety factor, no further collapse would have occurred.

Source? Thanks.

Originally posted by JimFetzer And since the fires were asymmetrically distributed in fact, there would only have been some tilting and sagging, not any actual collapse.

None of this is explicable absent the use of powerful explosives.

Bazant et al. seem to disagree with you. Maybe you will be writing a discussion showing them wrong. Right? Should we be expecting that this year?

Originally posted by JimFetzer Notice, too, that, if the trusses had fallen, one on another, over and over, down to the ground, then there should have been a stack of trusses that was some 13-14 floors in height. But it didn't happen.

Only in cartoon land would that happen.

Originally posted by JimFetzerAnd if the trusses fell, the core columns and the support columns would have remained, especially if the collapse had been initiated around 80th and the 94th floors.

Says you? You do realize that neither the exterior columns, not the interrior core was designed to stand on it's own, right?

Originally posted by JimFetzer
Notice, in particular, that the top 30 floors of the South Tower actually tilt and pivot initially, which means that they are not exerting ANY DOWNWARD FORCE AT ALL, EXCEPT AT THE EDGE.

So, the Leaning Tower of Piza is not exerting any force on the ground, except on one edge? Horse*****.

You do realize this doesn't help your cause, right? As that would mean that the edge was supporting the entire structure above it. What happens when the fulcrum stops resisting the structure above?

Originally posted by JimFetzer And in the North Tower, since there was no reason for the uppermost floors to have fallen first rather than around the 95th, it would have been like emptying a can of tennis balls onto the floor: you still have the upside down can remaining!

What the **** does that mean?

Originally posted by JimFetzer
And in this case, the sides of the can would be the external support columns and, right in the center of the can, the core columns would remain. But of course the support columns and the core columns were destroyed at the same time as the trusses. SO THERE IS NO EVIDENCE TO SUPPORT ANY COLLAPSE THEORY AT ALL. Get over it. Act like a man. Suck it up. The towers were taken out by a demolition under control. Q.E.D.

Ok. Good thing you're not responsible for any building safety design, or we would all be in trouble.

Originally posted by Fitzgibbon

Originally posted by psikeyhackr
The Laws of Physics don't give a damn about Conspiracy Theories.

Conspiracy Theories don't give a damn about the Laws of Physics.

FTFY

I don't give a damn about ANY conspiracy theories.

Nitwits on both sides of this issue keep everything muddied with conspiracy bullsh!t. The top of the north tower crushing the rest in less than 18 seconds is totally ridiculous in terms of physics. And then nitwits don't demand to know the TONS of STEEL and TONS of CONCRETE that were on every level when skyscrapers can't even hold themselves up if the designers don't get that right. Skyscrapers must withstand the wind. The plane may have done significant damage but nowhere near enough to bring a 400,000 ton skyscraper down in LESS THAN TWO HOURS.

This is probably the most idiotic bullsh!t in history. People who believe that planes and fire brought those buildings down have crap for brains.

psik

reply to post by psikeyhackr

Skyscrapers must withstand the wind.

Any level of wind? So all "skyscrapers" are therefore fully impervious to atmospheric stresses at any loading? Or are there limits? What happend when those limits are exceeded? And I hope you realize, of course, that not all "skyscrapers" are created equal, or the same.

The plane may have done significant damage but nowhere near enough to bring a 400,000 ton skyscraper down in LESS THAN TWO HOURS.

The damage caused by the plane was sufficient to weaken a structure that was not designed to hold up forever under those stresses. Even a child can see that.

This is probably the most idiotic bullsh!t in history.

There we agree.

Originally posted by JimFetzer
But since each floor could carry at least 20 times its expected live load,

What was the LIVE LOAD then Jim and do you actually know what the term live load refers to

I await your answer. In fact I know you dont because its not the LOAD I would have used in your GAMBIT to look like you know what your talking about!


Also suggest you look up DEAD LOAD, WIND LOAD,DYNAMIC LOAD,SHOCK LOADS do you want anymore!

reply to post by psikeyhackr


Jim says 500,000 tons now 400,000 tons would love to know where you get the stats from

Lets see for the mass given for the concrete used in the floors works out at between 700-800 tons per floor say 750 x110 =82,500 tons common figure given for steelwork is around 96,000tons so the air in the building must have been really heavy!

They also excavated down to the local bedrock and built from there so would not have been a great deal of concrete in the foundations no info given on that.

Originally posted by wmd_2008
reply to post by psikeyhackr

 

Jim says 500,000 tons now 400,000 tons would love to know where you get the stats from

You are welcome to try to find an exact number for the quantity of concrete in the towers.

The NIST never specifies a number for the total.

Lots of old sources say 200,000 tons of steel and 425,000 cu. yds. of concrete. The building had two types of concrete, 110 lb./cu ft and 150 lb./cu ft.

So that would be 100,000 tons of steel and more than 300,000 tons of concrete. That doesn't count everything else. So how does the NIST get away with not specifying exactly?

If we aren't told the tons of steel and tons of concrete on each and every level then all of the numbers are bullsh!t anyway. The distribution would affect how the building would respond to the wind which every skyscraper has to do.

psik

In NCSTAR 1-3, NIST admits that (a) it studied 236 samples of steel, (b) that it regarded those samples as sufficient to evaluate their exposure temperatures, (c) that it found only three locations at which temperatures had reached above 250*C (about 500*F), which implies (d) that 233 samples had not been exposed to temperatures above 500*F. Here is NIST's own answer to a "frequently asked question"--among the most important--and my comment:

www.911scholars.org...

3. How could the WTC towers have collapsed without a controlled demolition since no steel-frame, high-rise buildings have ever before or since been brought down due to fires? Temperatures due to fire don't get hot enough for buildings to collapse.

The collapse of the WTC towers was not caused either by a conventional building fire or even solely by the concurrent multi-floor fires that day. Instead, NIST concluded that the WTC towers collapsed because: (1) the impact of the planes severed and damaged support columns, dislodged fireproofing insulation coating the steel floor trusses and steel columns, and widely dispersed jet fuel over multiple floors; and (2) the subsequent unusually large, jet-fuel ignited multi-floor fires weakened the now susceptible structural steel. No building in the United States has ever been subjected to the massive structural damage and concurrent multi-floor fires that the towers experienced on Sept. 11, 2001.

NOTE: This simply ignores (a) most of the fuel was consumed in those massive fireballs upon impact, (b) the fires were oxygen-starved, as the billowing black clouds indicated, (c) they were burning far below 1,000 degrees C, probably on the average closer to 250 degrees C, which was (d) far too low to have caused the steel to weaken, much less melt. Indeed, (e) even if the fires had been as hot as 1,000 degrees C, they did not last long enough to bring about effects of that kind. Compare the 13 February 1975 fire on the 11th floor of the North Tower, which burned hotter (around 1,000 degrees C) and longer (more than three hours), enveloping the core and destroying 65% of the floor, yet none of the steel--in particular, the trusses--had to be replaced. That is as close to a crucial experiment (confirming controlled demolition while refuting the official account) as could be arranged insofar as the buildings are no longer standing.

reply to post by hooper

Originally posted by psikeyhackr

Originally posted by wmd_2008
reply to post by psikeyhackr

 

Jim says 500,000 tons now 400,000 tons would love to know where you get the stats from

You are welcome to try to find an exact number for the quantity of concrete in the towers.

The NIST never specifies a number for the total.

Lots of old sources say 200,000 tons of steel and 425,000 cu. yds. of concrete. The building had two types of concrete, 110 lb./cu ft and 150 lb./cu ft.

So that would be 100,000 tons of steel and more than 300,000 tons of concrete. That doesn't count everything else. So how does the NIST get away with not specifying exactly?

If we aren't told the tons of steel and tons of concrete on each and every level then all of the numbers are bullsh!t anyway. The distribution would affect how the building would respond to the wind which every skyscraper has to do.

psik

edit on 23-2-2011 by psikeyhackr because: sp err

The figs i GAVE were for a tower as we are talking about impacts and related damage.

Would like to see a source for the concrete because above ground level the ONLY concrete was in the floor slabs! may be stairs in side?

Empire State Building is 60,000 tons of Steel WTC are not going to be much more as the ESB has a 3d grid of steelwork and a heavy masonry facade so the 96,000 ton for WTC steel looks about right.

Lets look at you concrete for WTC lets see the maths your going to love this!!!

425,000 cu yrds is 425,000x27 = 11475000 cb feet lets average the concrete mass to 125/cu ft
so 11475000x125= 1434375000lbs divide that by 2240 lbs per ton (uk) =640,346 tons if US 2000 lb short ton its 717187 tons.

If the only concrete above ground level is the floor slabs an possible stair cases its a BIG difference.
800x110=88000 tons + stairs if concrete.

So look like thats a guess then does it not!

Originally posted by JimFetzer


www.911scholars.org...

3. How could the WTC towers have collapsed without a controlled demolition since no steel-frame, high-rise buildings have ever before or since been brought down due to fires? Temperatures due to fire don't get hot enough for buildings to collapse.

The collapse of the WTC towers was not caused either by a conventional building fire or even solely by the concurrent multi-floor fires that day. Instead, NIST concluded that the WTC towers collapsed because: (1) the impact of the planes severed and damaged support columns, dislodged fireproofing insulation coating the steel floor trusses and steel columns, and widely dispersed jet fuel over multiple floors; and (2) the subsequent unusually large, jet-fuel ignited multi-floor fires weakened the now susceptible structural steel. No building in the United States has ever been subjected to the massive structural damage and concurrent multi-floor fires that the towers experienced on Sept. 11, 2001.

NOTE: This simply ignores (a) most of the fuel was consumed in those massive fireballs upon impact, (b) the fires were oxygen-starved, as the billowing black clouds indicated, (c) they were burning far below 1,000 degrees C, probably on the average closer to 250 degrees C, which was (d) far too low to have caused the steel to weaken, much less melt. Indeed, (e) even if the fires had been as hot as 1,000 degrees C, they did not last long enough to bring about effects of that kind. Compare the 13 February 1975 fire on the 11th floor of the North Tower, which burned hotter (around 1,000 degrees C) and longer (more than three hours), enveloping the core and destroying 65% of the floor, yet none of the steel--in particular, the trusses--had to be replaced. That is as close to a crucial experiment (confirming controlled demolition while refuting the official account) as could be arranged insofar as the buildings are no longer standing.

reply to post by hooper

 

JIM I am sure you claimed some background in science, so the black smoke indicated lack of oxygen what other things in a office fire could burn and produce black smoke. Go and have a think Jim.

Some large holes in the walls did you forget those 80 floors up so no wind then? the building would act like a chimney drawing in air.

Temperatures paper itself burns at over 200 c what about the carpets the furniture, computers etc etc also how did the North Tower fire reached a 1000 c what was different because an office fire will reach its maximum temperature quickly.

Have you a link to the steel temps you claim!!!

Have a look here Jim plenty of smoke and plenty of flames

Im of the opinion Dr Judy Wood's theories about what caused the collapse and disintegration of the towers are the closest explanations yet to what actually happened.

I think the problem we still have however is technology was used on 9/11 that we dont even know about yet let alone understand.

One things for sure - neither thermite, TNT, nukes, nor planes caused the destruction of the WTC's.

Originally posted by JimFetzer
In NCSTAR 1-3, NIST admits that (a) it studied 236 samples of steel, (b) that it regarded those samples as sufficient to evaluate their exposure temperatures, (c) that it found only three locations at which temperatures had reached above 250*C (about 500*F), which implies (d) that 233 samples had not been exposed to temperatures above 500*F. Here is NIST's own answer to a "frequently asked question"--among the most important--and my comment:

Don't ignore my lengthy post above. It's got quite a few sources missing that I have asked you for on more than one occasion.

I also have shown you that a hydrocarbon fire will burn much hotter than 500 deg. F. Not suprisingly, you ignored it.

Care to address the post?

Of course, I am hardly alone in challenging the entire report. It does not surprise me that FDNY343 is going to cite it. What bothers me is that he appears to be incapable of EVALUATING IT, since its function is to cover up the actual causes of the destruction of the Twin Towers. I should have thought that would have been obvious by now.

reply to post by FDNY343

You ignore that (a) no steel-structure high-rise has even collapsed due to fire in his history of engineering, (b) that NIST's own data substantiates that these fires were burning at 500*F and (c) that there were no conditions that would have brought about a collapse in any case. One of us is ignoring the evidence--including even the gross observable evidence from "New 9/11 Photos Released", but it isn't me. Get a grip, FDNY343. You have no idea what happened on 9/11 and appear to be willing to let yourself be played for a sap by the Bush administration. Why is that?

reply to post by FDNY343

The dead load is weight of the unoccupied building with respect to the support capacity of each floor, while the live load is the dead load plus the additional weight of the personnel, furnishings, computers and everything else that would add to its weight when occupied. John Skilling observed that the towers had been constructed with a safety factor of 20. Chuck Boldwyn has calculated that is was actually much greater than that. Because the steel tapered off with the height of the building and the reduced weight it had to support, the upper 16 floors of the North Tower, for example, represented only 1.8% of the mass of the building and the lower 94 represented 98.2%. There is no way that those upper floors could overcome the support capacity of the lower--and that is before taking into account the safety factor. The arguments for any kind of collapse have no foundation. They are fantasies, not facts. And I find it extraordinary that so many are willing to display their ignorance and irrationality about this.

Here's a discussion from Wiki, but there are many others. This is not an obscure question.

Dead loads

Dead loads are the self weight of components put on the structure like plasterboard or carpet and the structure itself. Typically they are relatively constant throughout the structure's life, and so they are also known as Permanent loads[1][2][3]. The designer can also be relatively sure of the magnitude of the load as it is closely linked to density of the material, which has a low variance, and is normally responsible for the specification of the component (e.g. plasterboard thickness) and can check it on-site.

Dead loads also include forces set up by irreversible changes in a structure's constraints. For example, loads due to settlement, the effects of pre-stress or due to shrinkage and creep in concrete.
[edit] Live loads

Live loads, sometimes referred to as probabilistic loads include all the forces that are variable within the object's normal operation cycle not including construction or environmental loads. Using the staircase example the live load would be considered to be –

* Pressure of feet on the stair treads (variable depending on usage and size)
* Wind load (if the staircase happens to be outside)

Live loads (roof) produced (1) during maintenance by workers, equipment and materials; and (2) during the life of the structure by movable objects such as planters and by people.[1]

Live Load (Bridge) produced by vehicles traveling over the deck of the bridge.[4]
[edit] Real world usage

The reason for splitting loads into these categories is not always apparent, and in terms of the actual load on the object there is no difference between dead or live loading (neglecting inertial and vibrational characteristics). For the most part, the split occurs for use in safety calculations or ease of analysis on complex models.

When considering the feasibility of a structure, safety always takes precedence and because of this, governing bodies around the world have regulations to which structures have to adhere. Using the example of the staircase, if it was intended for use in the UK it would have to follow British and European Standards

* BS 4592 – Industrial type flooring and stair treads
* BS 5395 – Code of practice for the design of straight stairs
* Other standards specific to the application (e.g. BS 14122-3:2001 – Permanent means of access to machinery. Stairways, stepladders and guard-rails)

Within these standards a safety factor is usually determined where the structure should be able to withstand a certain force above the maximum expected load. Once again using the staircase example, assuming it is an indoor medium-usage industrial staircase the current safety factor would be 1.2 times the maximum stress imposed by the dead load and 1.6 times the maximum stress imposed by the live load. The reason for the disparity between values, and thus the reason the loads are initially categorised as dead or live is because while it is not unreasonable to expect a large number of people ascending the staircase at once (or the wind speed increasing, snowfall or any other live load increase), it is less likely that the structure will experience much change in its permanent load. The same can be said of many structures and so it is convenient to assess loading based on its application.

reply to post by wmd_2008

You are long on words and short on substance, FDNY343. I have already addressed the kinds of questions you ask, including, of course, the source of information about the 236 samples of steel that NIST tested. It is in its own report: In NCSTAR 1-3, NIST admits that (a) it studied 236 samples of steel, (b) that it regarded those samples as sufficient to evaluate their exposure temperatures, (c) that it found only three locations at which temperatures had reached above 250*C (about 500*F), which implies (d) that 233 samples had not been exposed to temperatures above 500*F. So the problem may be that, as this case illustrated, the problem is your lack of reading comprehension. If I played your little game, I would be repeating myself forever. Get a grip. You have been conned.

reply to post by FDNY343

reply to post by JimFetzer

NOTE: This simply ignores (a) most of the fuel was consumed in those massive fireballs upon impact,

Opinion, conjecture, irrelevant.

(b) the fires were oxygen-starved, as the billowing black clouds indicated,

Conspiracist mythology.

(c) they were burning far below 1,000 degrees C, probably on the average closer to 250 degrees C, which was (d) far too low to have caused the steel to weaken, much less melt.

This is very technical, please cite some technical source (ASTM?) for this pronouncement. Also, please bulletin the structural engineering community, they would love to know this kind of stuff. They have been suffering under the misconception for years that thermal energy has an effect on solid matter. Little did they know, huh?

Indeed, (e) even if the fires had been as hot as 1,000 degrees C, they did not last long enough to bring about effects of that kind.

Oh well, that ends that, huh? So it has been declared, so it now must be marked in the vaunted halls of "truth".

Compare the 13 February 1975 fire on the 11th floor of the North Tower, which burned hotter (around 1,000 degrees C) and longer (more than three hours), enveloping the core and destroying 65% of the floor, yet none of the steel--in particular, the trusses--had to be replaced. That is as close to a crucial experiment (confirming controlled demolition while refuting the official account) as could be arranged insofar as the buildings are no longer standing.

After an exhaustive investigation I can tell you, without a doubt, that no passenger jetliners slammed into the 11th floor of North Tower of the World Trade Center complex in February of 1975.