No Steel-Structured Building Has Ever Collapsed Due To Fire

reply to post by St Udio




So your saying that WT7 was a controlled demolition?
How long does something like that need to put in place?
Not an expert but I assume it would take some serious planing.
Hours? Days?.....

Let me ask. Have you ever, in the line of duty as a firefighter, heard of partial collapses initiating a global collapse? Ever? Columns and all?

One of the first things they tell you is "Never trust a truss" - all it
takes is failure of one component of a truss to fail and that entire
truss is compromised. As the truss fails stress transfers to adjacent
trusses which in term fail - entire roof unzips and collapses. Ever
seen overheated steel structural beam expand push out a wall? Seen
these on fire ground....

Originally posted by PplVSNWO
Can you explain how the steel had gotten hot enough to fail? NIST claimed the air temps may have been 1800 degreesF, which is the max burn temp of jet fuel. How can the air temp be 1800 degrees if the open air burn temp of jet fuel is around 600F? Does wood and office furniture burn at 1800 in open air, or are they implying that the towers were actually big jet engines?
Do you have a link to where NIST found that the steel had been heated anywhere near the temperature they are claiming(1800)??

Thanks

That temperature of 1800F or 982C is supported from at least 3 different sources.
Aerial surveying of the hotspots in the rubble fires indicated about 1000C.
FEMA analysis of corroded steel indicated long-term heating at around 1000C in a corrosive environment.
NIST assembled a group of typical computer workstations (desk, chair, PC, monitor, manuals & papers) as used in the buildings and burnt them with and without jet fuel as accelerant. The maximum temperature at the fire's peak (at ceiling height above it) was measured at, or slightly above, 1000C.

So yes - typical building contents could produce that temperature in a fire.

reply to post by Pilgrum


Even if it's possible, did they not also state that most of the fuel burned up instantly on impact? How would there be enough fuel to burn on multiple floors hot enough to reach the claimed temp, in two separate buildings? Do you have a link that describes the test NIST performed?
Also, couldn't the corrosion and hi temp that you are talking about be caused by thermate?

Thanks for any help.

Originally posted by Griff
If the concrete in the Windsor was strong enough to hinder a global collapse caused by the upper floors collapsing, what happened to the stronger uneffected steel in the WTC to cause a global collapse?

And why hasn't any official story come out as to why this happened? Just "it was inevitable".

The more I look at it, the more it looks like it wasn't a failure of the steel members themselves because the majority came down (core & outer wall sections) in remarkably good shape IE unbent and unbroken in the strongest sections. It appears that the connections failed instead (bolts and welds).

As to how those connections failed, everyone can insert their favorite conspiracy theory but I don't feel any are needed as yet. The vast majority of those failed connections were not heat affected.

Some may keep repeating 'buildings with worse damage didn't collapse' but that just shows that the WTC buildings were damaged enough to do so while the 'other' buildings were not and fire was definitely a factor in how it started but not the only factor. All those inclined to believe that planted devices were involved are welcome to do so but, at some point, they'll need evidence to support it beyond the fact that the buildings failed.

Originally posted by Pilgrum

That temperature of 1800F or 982C is supported from at least 3 different sources.
Aerial surveying of the hotspots in the rubble fires indicated about 1000C.
FEMA analysis of corroded steel indicated long-term heating at around 1000C in a corrosive environment.
NIST assembled a group of typical computer workstations (desk, chair, PC, monitor, manuals & papers) as used in the buildings and burnt them with and without jet fuel as accelerant. The maximum temperature at the fire's peak (at ceiling height above it) was measured at, or slightly above, 1000C.

So yes - typical building contents could produce that temperature in a fire.

That's disingenuous at best.

The NIST fire temp reading records the heat of the fire, not the heat that was transferred to the steel members, which is an entirely different story. To heat the massive core and facade columns to 1000C, you are going to require much more than office fires in open-air conditions burning an hour or less.

I'm really surprised to read such a flagrantly misleading post. What temperature did the steel members reach in NIST's experiment?

reply to post by PplVSNWO


NISTNCSTAR1-5 deals with the fires and is over 60MB if you want to study it.

There was an estimated ~10000 gallons of fuel remaining in the aircraft and there's an estimate of as little as 15% of that being consumed in the initial fireballs, leaving as much as 7000+ gallons to spread through the building and act as an accelerant for more longlasting fires.

It's all estimates because not enough survived to take measurements.

reply to post by gottago


Not trying to be misleading at all as I was only referring to the likely maximum temperature of such a fire in line with the question that was asked with actual supporting observations from reputable sources. Thermal conductivity characteristics of steel was not mentioned

You might note my earlier post about the observation of most of the failed structure actually being unheated yet it still failed.

Originally posted by Pilgrum
reply to post by gottago

 

Not trying to be misleading at all as I was only referring to the likely maximum temperature of such a fire in line with the question that was asked with actual supporting observations from reputable sources. Thermal conductivity characteristics of steel was not mentioned

But again, the heat of a fire and the heat transfer to massive steel beams are not at all equivalents. You don't need an engineering degree to know that.

And to cite the thermal hotspots/molten steel at ground zero as some sort of proof that such temperatures were reached by regular office fires is really jumping the shark.

That is turning one of the most obvious and important pieces of evidence of abnormalities in the collapses on its head; in NY, that's called "chutzpah"

Originally posted by thedman
One of the first things they tell you is "Never trust a truss" - all it
takes is failure of one component of a truss to fail and that entire
truss is compromised. As the truss fails stress transfers to adjacent
trusses which in term fail - entire roof unzips and collapses. Ever
seen overheated steel structural beam expand push out a wall? Seen
these on fire ground....

I'm not talking about trusses or beams. I'm talking columns. In every building collapse from fire, that I've ever seen, the columns were mainly still intact. Please point to ONE building in history where the trusses and beams caused the columns to buckle and telescope into themselves causing a global collapse. Please. You seem to think it happens all the time. So, you should know of at least ONE time right?

[edit on 4/16/2008 by Griff]

And why did the whole section that was tilting AWAY from the rest of the building not fall down with its integrity intact? Why did it too turn to dust?

reply to post by Griff


This IS a good point. Columns have an entirely different structurall integrity than trusses and beams. Of course trusses and beams were damaged, a plane just flew into the building. But columns? even if the plane broke some, the collapse would have happened right away, not an hour later.

Theory - they let it ride for an hour for A) shock and awe B) just so they can say fire is what did it.

Otherwise, why didnt the collapse happen sooner?

To put an end to this stupidity.

My name is Ethan Case, I'm a Mechanical Engineering student, and work at an Engineering firm in Manhattan.

Now that I have shown my credentials.

Fire temperature in the buildings was around 1000 degrees. Thats been confirmed by multiple sources and proven in controlled experiments to be possible.

First thing everyone points at is how the steel beams melted when the fire wasn't hot enough. Its been said here by several bright individuals, but bears repeating. The steel did not melt. When steel gets hot, it becomes more elastic. There is a constant called Modular Elasticity. Denoted in equations by the letter E. If I remember correctly, steel is around 70 x 10^ something GPa, but thats neither here nor there.

the point is when the steel heats up, its constant of elasticity changes. Math wise, this alters the amount of force its able to take without deforming or shearing.

Roughly 500,000 tons of # were above the crash zone on one of the towers. The steel, weakened by impact, and further weakened by heat, bent, buckled, and folded/sheered under the tremendous load it wasn't designed to hold. As the floors fell, they acquired the weight of floors they fell on, plus momentum. It wasn't total freefall, but the acceleration of the falling increased exponentially as falling weight and momentum increased, so it was pretty damn close to it. Trade center has center spine and exoskeleton. They are strongest on the outside, and in the center. Stuff thats falling falls in the path of least resistance. Everything fell away from the strongest resistance, thus falling inward and vertically. As it fell, it pulled pieces of the exterior exoskeleton inward with it.

The official story is the way it happened. it is perfectly logical, and any engineer would have come to that conclusion without the government telling them.

as for building 7, know that there was some emergency services stuff located in there. anyway, most of the damage done to it happened because roughly a million tons of flaming steel fell from several thousand feet in the air and crashed right next to it... twice. the entire earth shook when those towers fell, #ing with the structures of all the buildings. also, the south side of the building was hit by debris and left a massive gash in its superstructure. also, its 47 stories, which makes it quite tall, like the towers (sensing a pattern?) and furthermore, because of emergency services and probably for convenience, there were 24 transformers in building 7, 10 at street level, 12 on 5th floor and 2 on seventh. i've got news for you guys, transformers are filled with a certain flammable substance called oil, and when you've got 24 massive containers of oil surrounded by fire for a few hours, those things blow up. they take out a floor or two with them, and they are low floors, which means there are 40 floors of stuff weighing down on them. thus 7 was flattened.

reply to post by firehead

Google Video Link

According to that video, the building was built to be so very strong that it could withstand loads 20x static.

Another statement was that you could remove every exterior column from the base on one side of the building, and put it in a hurricane wind, and it would still stand.


And what about the statement by Frank A. DeMartini, WTC Construction and Project Manager:

"I believe that the building could sustain multiple impacts of jetliners"


After you watch the video, what is your response to your statement that the building was barely strong enough to hold itself for a few more minutes after the plane hit?


For the life of me, I can't explain how global collapse could happen when 70 or more stories suffered no structural damage. Wouldn't those stories resist the fall, at least enough to slow it down? It fell in 10 seconds....

Originally posted by firehead
My name is Ethan Case, I'm a Mechanical Engineering student, and work at an Engineering firm in Manhattan.
If I remember correctly, steel is around 70 x 10^ something GPa, but thats neither here nor there.

So, you're a MechEng student and you can't remember the exponent? Posting the correct figure would make your post more believable. I guess you didn't have the time to open your text book when you were posting?

As the floors fell, they acquired the weight of floors they fell on, plus momentum. It wasn't total freefall, but the acceleration of the falling increased exponentially as falling weight and momentum increased, so it was pretty damn close to it.

Please explain these sentences to me?

Gravity will accelerate objects at approximately 9.8 m/s^2, near enough to being constant over the displacement of the collapsing tower. How can acceleration increase exponentially during the collapse? What was the initial acceleration and what was the final acceleration? Where is your regression analysis to show an exponential increase in acceleration? You can post the figures and equations for me, I know how to check them.

Perhaps you're confusing velocity with acceleration? Check your text books again and let me know what you really meant.

Thanks.

Originally posted by firehead
It wasn't total freefall, but the acceleration of the falling increased exponentially as falling weight and momentum increased, so it was pretty damn close to it.

Acceleration due to gravity isn't exponential. There is no exponential or logarithmic function in the equation. It's a constant.

a = 9.8 m/s*s


Are you sure you're an engineer? This is 1st semester general non-calculus physics.



OH, tezzajw looks like you beat me to it. You were thinking what I was thinking ;-)




[edit on 20-4-2008 by ianr5741]

Originally posted by gottago
But again, the heat of a fire and the heat transfer to massive steel beams are not at all equivalents. You don't need an engineering degree to know that.

And to cite the thermal hotspots/molten steel at ground zero as some sort of proof that such temperatures were reached by regular office fires is really jumping the shark.

That is turning one of the most obvious and important pieces of evidence of abnormalities in the collapses on its head; in NY, that's called "chutzpah"

The heat transfer proves to be more a function of where, and how much, fireproofing was removed in the immediate vicinity of heat source and there's what I consider very good support for the 1000C figure. Even if there were isolated higher temps than that (>=1500C) pre-collapse from whatever source, normal or introduced, there simply wasn't sufficient time for large scale melting to occur.

Post collapse is a different situation with time on its side. I can't honestly deny the melting of steel and other material in that environment but connecting it to the pre-collapse situation is a bit more tenuous apart from the fires starting there.

I'm not attacking the evidence of melting as some have done but connecting it as a factor in building failure becomes a little hazy unless some startling evidence is yet to surface.

Originally posted by ianr5741
Acceleration due to gravity isn't exponential. There is no exponential or logarithmic function in the equation. It's a constant.

I think we're starting to split hairs here.
Yes we use a gravitational acceleration factor as a constant (eg 9.8m/S^2) but consider what acceleration is IE rate of change in velocity per unit time.

The key factor in the expression of that constant is the exponent of time seconds^2 so doesn't that make the constant itself exponential IE non-linear?

Originally posted by firehead
My name is Ethan Case, I'm a Mechanical Engineering student, and work at an Engineering firm in Manhattan.

If I remember correctly, steel is around 70 x 10^ something GPa, but thats neither here nor there.

You're not remembering correctly. E for steel is around 30,000,000 psi (usual value used is 29x10^6 psi) or around 190-210 GPa.

en.wikipedia.org...'s_modulus

BTW, Civil Engineer here. Nice to meet ya.

Thats not true at all,in the 70's I was in the lumber buisness,a glu-lam or Laminated beam will hold up better during a fire than a metal beam,next time do a little reasearch

reply to post by ianr5741


i agree with what you said. earlier, i had said the same thing. the architects built and designed these buildings with this scenario in mind. why? back in the 40's, a b-17 stuck the empire state. knowing what happened then, they knew these buildings could be hit by a large passenger jet. these buildings should not have come down.