Professional engineer Jon Cole cuts steel columns with thermate, debunks Nat Geo & unexpectedly repr

Originally posted by bigyin
You know this is something thats always bothered me, when you heat steel it expands quite a lot. When I think about that in my mind that would push the columns out not pull them in.

You are correct. In the beginning the columns will be pushed out. Only after the trusses are deformed they start pulling.

Like this guy says once the steel cooled again it would then pull the columns in but the towers didnt get the chance to cool down.

Some people say the fires were already cooling down again in the WTC. I am not really sure if the temperature could drop enough in such a short time. It was just a theory I read, thought it would be interesting to share.

reply to post by bsbray11


I tried to explain to my fullest capacity, but I failed. So I am sorry I can't help you. Remember that I am an electrical engineer, I think you can better contact a structural engineer.

Originally posted by bigyin

When you have a floor supporting weight, the floor starts sagging from the heat," Varma said. "It expands, but it's got nowhere to go so it starts bowing down, which produces pulling forces on the building's frame. It starts pulling on the columns and then it becomes longer and permanently deformed. After the fire, it starts cooling, and then it starts pulling on the columns even harder.

You know this is something thats always bothered me, when you heat steel it expands quite a lot. When I think about that in my mind that would push the columns out not pull them in.

I was about to say the same thing but you beat me to it. They even say themselves the steel tries to expand but has nowhere to go. That's not pulling, that's pushing trying to expand. The Cardington tests showed the same thing in 2000. The reason heated beams "sag" isn't because they've become like wet noodles, but because they are trying to expand while rigidly held in place on the ends by the columns, so the middle bows out since it's where the beam isn't being rigidly held. It's a form of thermal expansion.

As far as pulling once it starts cooling, I'm assuming while trying to retain the same shape, that brings up more questions than answers as far as the WTC. First of all the truss/beam would obviously have to be heated until it would permanently deform with it loads, and not just some elastic deformation. 600 C takes away about half of steel's integrity, so for example it would have to be at half of its loading capacity or greater and then uniformly heated to 600 C, or at 3/4 of its loading capacity or greater and uniformly heated to 500 C, etc.

I also wonder how long it would take to heat to any of those temperatures, whether or not these temperatures are even realistic, what percentage of their loading capacities the trusses were at, and how long would it then take to cool if they were heated to such high temperatures. And then what forces are we talking about, and what would it take to dislodge perimeter columns with their spandrel plates? I have to agree that the connections would go first looking at how much smaller they are and more easy to give than the columns themselves.

Originally posted by -PLB-
I tried to explain to my fullest capacity, but I failed. So I am sorry I can't help you. Remember that I am an electrical engineer, I think you can better contact a structural engineer.

So once again you must be going on faith.

All I asked was what form of deformation this "sagging" was and how that form of deformation could exert a tension force pulling the columns inward.

I'm not a structural engineer either but even I can understand that if NIST's hypothesis had an credibility they could have described this to you, or anyone, in their report.

Anyway, its all ok with me that you all attack the explanations I come with so rigorously. I would however like to hear what any of you think caused the bowing. If my explanations are totally wrong, what else could it be?

Originally posted by smurfy
I understand that Anok,
The point I was making, was that it was a late event in the collapse, and that all below had disintegrated. The lean had no bearing on the collapse, other than acting like a shroud.

I know you understand that, I was just adding to your post, it wasn't really directed at you.

It was just an excuse to keep sticking evidence in the faces of the 'debunkers', who keep trying to pretend it doesn't exist. You have to keep reminding them.

reply to post by -PLB-


It was those sneaky stealth ninjas that planted the paint on thermite high explosive bombs. They saw it wasnt working fast enough, so they grabbed long invisible cables, hooked them up to the exterior columns, and started to pull in unison!

I dare anyone to prove this isnt true or capable. They have stealth suits in the works! They have those large exoskeletons that are being designed for soliders to lift 200X their weight. Add it up folks. Thats what caused the bowing inward!

Originally posted by -PLB-
Anyway, its all ok with me that you all attack the explanations I come with so rigorously. I would however like to hear what any of you think caused the bowing. If my explanations are totally wrong, what else could it be?

What explanation did you even give? You can't say what form of deformation the sagging was or especially how that would then exert a "pull" force on the perimeter columns. The ways steel can deform in heat are well-understood.

Originally posted by -PLB-
Remember that I am an electrical engineer, I think you can better contact a structural engineer.

What kind of electrical 'engineer' are you?

When I took my engineering fundamentals course, which all engineers take, many years ago physics was a huge part of it.

In fact here we go...

Required Courses: Electrical Engineering

PHYS 101 Fundamentals of Physics I 4.0
PHYS 102 Fundamentals of Physics II 4.0
PHYS 201 Fundamentals of Physics III 4.0

www.drexel.edu...

It's not hard to tell when someone has not taken any of those courses.

reply to post by GenRadek


I see the debunkers have nothing of substance to add to the debate as usual, so they attempt crass humour instead.

Yes Gen yer funny.

But all you've done is prove you don't have the intellect to add anything to the thread, why did you even bother?

Ridicule is the tool of those in power who wish to control popular thought, it's not a good debate tactic. It's obvious you have more than a passing interest in the 9-11 discussion and it has nothing to do with finding the truth.

reply to post by ANOK


ANOK, I have said my part many many many times here. I have posted all relevant comments and facts about this, many times in the past. But, since you ignore it, have it go over your head, well, what more is there for me to do? It's like talking to a brick wall.

So I decided to go the route of how a truther would explain it.

But if you want to see what I said about it, feel free to go to other pages. I'm not going to repost the same thing over and over, just so can ignore it and ridicule it, and think you are much more superior, instead of actually learning something that is counter to your dearly held faith of the TM.

Originally posted by bsbray11

I tried to look up the role of the dampers while posting that above but I couldn't find what I was looking for. I know they absorbed some wind loads but I'm not sure what their role transferring loads from the trusses might have been. You could be right as far as I know.
...............
Exactly. That's what I was trying to find out, because it seems like they acted almost as the structural equivalent of a capacitor. If so then they would buffer any extra horizontal tension loads, if there were any to begin with, and I haven't seen any reason to suspect there were.

Imo the perimeter columns that were bucking, weren't because of the trusses, but because of the core structure being compromised. Just my opinion. When the WTC1 "collapse" initiated they just started folding over themselves where they were weakest at the exact same time the antenna start sinking straight down, and that antenna was supported by the core, not the perimeter structure, though the hat truss would try to redistribute all the core's loads onto the perimeter. Then it was a split second after that, that row after row of violent ejections started coming out until the "collapse" was completely obscured by the massive debris cloud.

edit on 13-1-2011 by bsbray11 because: (no reason given)

You have to realize, the dampers themselves were not large objects connecting the floor trusses. Also, the dampers themselves would not have any significant effect on slowing the truss deformation. I'm sure we all have seen this picture of the truss ends:


It is widely known that all light steel trusses are inherently dangerous in fires. Firefighters will not be allowed to enter a structure that has a truss roof. As to why this is, its simple: Trusses react to fires badly. They heat up rapidly. When they heat up, they begin to expand. However, when they do, the structure on either side may hold in check, so it is forced to start sagging. Steel also undergoes an event called "creep" when it is heated up and exposed to extra loads. As the truss sags down, it begins to pull in the exterior. In structures that have trussed roofs, this causes a collapse of the roof. There are many publications of this on firefighter sites, books, and magazines. There is a saying: Never trust a truss. There is a reason behind it.

As to WTC, you not only had one, or two or three trusses sagging. There were a LOT of them doing that in unison. Granted, some may have heated unevenly, or some were exposed to higher temps than others. Either way, that set the stage for deformation of the entire structure. But it must be remembered: the trusses were the FIRST to be most adversely affected by heat. The exterior columns were thicker and therefore took longer to heat up. This may explain why they didnt bow out during the initial heating. They were still rigid enough to withstand the extra horizontal stresses. But over time and heating, the exterior columns on the affected floors also began to experience heat and horizontal load creep. Some floors were reported to have partially collapsed when the truss connections failed. This would have added more strain and stresses to the system.

The core was the thickest of the members. However, the ones that would have been affected by fire would be the ones that had the fireproofing removed via impact, and damaged. They also began to show the affects of the heating and extra horizontal stresses, including creep. They too played a part in the deformation.

Now you asked later about what type of deformation the sagging did? It sagged. Meaning, the floor truss was sagging down. When you have a whole floor of them sagging down, now you are dealing with the floor load below the the original level of the truss. This is what would cause the pulling in stresses. Also what if a few floors above had already collapsed down on top of the rest? A police pilot did mention this in one of the towers.

Hope this makes sense, but that is my understanding of it.

reply to post by GenRadek


wtc.nist.gov...

Or we can always go back to the source and figure it out form there!

Originally posted by GenRadek
It is widely known that all light steel trusses are inherently dangerous in fires. Firefighters will not be allowed to enter a structure that has a truss roof. As to why this is, its simple: Trusses react to fires badly. They heat up rapidly. When they heat up, they begin to expand. However, when they do, the structure on either side may hold in check, so it is forced to start sagging. Steel also undergoes an event called "creep" when it is heated up and exposed to extra loads. As the truss sags down, it begins to pull in the exterior.

You just said the truss sags because it's trying to expand but is restrained on the ends, which is true. Then you say this same deformation causes it to "pull" on the exterior columns. How do you reconcile an expansion and a contraction happening simultaneously?

Originally posted by GenRadek
Steel also undergoes an event called "creep" when it is heated up and exposed to extra loads. As the truss sags down, it begins to pull in the exterior. In structures that have trussed roofs, this causes a collapse of the roof. There are many publications of this on firefighter sites, books, and magazines. There is a saying: Never trust a truss. There is a reason behind it.

Why is it that you all insist there were extra loads on the trusses because they heated up?

What assumption do you base the claim that the trusses could pull in the exterior columns?

You are not adding anything new to this discussion, we have already covered this. If you go back and read the posts you will see this idea had been debunked, the trusses cannot both sag AND pull in the columns they were connected to. Common sense should tell you the trusses would lose their ability to apply any load to the exterior columns if they were malleable enough to sag under their own weight (not any extra weight that wasn't there before they heated).

But regardless there is no way one hours worth of fire could cause the trusses to get hot enough to sag to that extent anyway. It couldn't be done in tests!

To my eyes what NIST claims is bowing outer columns is simply the aluminum facade. There was a gap of a few inches between the aluminum and the steel, it is required to prevent galvanic corrosion. The aluminum deformed and bowed inwards towards the columns.

reply to post by bsbray11


Why don't you just Google the subject? Anything I write is misunderstood, taken out of context or ignored. There are many papers and articles about it. Try for example this

reply to post by Nutter


One thing that does not seem to get mentioned...is the concept in the NIST report says the 5/8 " a325 bolts sheared....now soon as this occurs..all horizontal forces being applied from thermal expansion and thermal sagging would cease....

“Finding 7: All four tests demonstrated that the floor assemblies were capable of sagging without
failure. The unrestrained test, which had two 0.875 in. bolts fastening the main truss to the truss
seats, did not sag sufficiently to bear on the bolts.” (NCSTAR 1-6 page lxxii, para4)

we also have NIST saying that inward bowing was observed in only limited areas of the structure...

Inward bowing was observed only on the east face. The south face had extensive aircraft impact damage, and the damaged floors were not capable of imposing inward pull forces on the south
face. There was no impact damage or fire on the west floors to cause pull-in forces on the west
face. (NCSTAR 1-6 p334 para3)

Floor sagging induced inward pull forces on the east wall columns.
About an additional 1/3 of the connections to the east exterior wall on floor 83 failed due to
thermal weakening of the vertical supports. (NCSTAR 1-6 p307 para13,14)

once again contradictory interpretation to me...If NIST says these connections fail...then there is absolutely no more inward pulling force being exerted....SNAPSNAPSNAP.....we will go back PLB rope senario shall we...rope pulls in the trees...said rope snaps....trees are not longer being pulled.

but as first stated...if...big if..If the deflection was say 10" which according to NIST was sufficient to cause Shearing of said bolts...(remembering the fires wer not covering entire floors)

would that be sufficient to cause buckling of exterior wall columns....now also remember the the trusses being attached to the interior plates on the Innercore.

The NIST report failed in the fact it relied more on the models than the observed failures...the reason it did so is because the observed failures did not correspond to the Models.

So conclusion...a horizontal force caused due to thermal expansion and thermal sagging in localized areas...cause bolts to shear ...would this said localized application of forces be enough to cause failure in the wall columns due to buckling when there is very little observed instances of this happening...and also rememebering that soon as the bolts shear...there is no longer this applied force on the exterior wall columns...we will not mention the interior core as that would not even be possible.

reply to post by -PLB-


well for one thing the bowing of the trusses is...and always has been hypothetical....it is based on models...the trusses mysteriously vanished from site...yet again a slow boat to china.
so i would not even accept the bowing in the first place because it is conjecture.
now as i posted in the previous....IF and big IF the bowing was occuring ..and acording to NIST the bolts sheared even thoughin testing the bowing was not sufficient to even cause failure.
once said failure occurs...horizontal force is no longer there.

reply to post by plube


Bowing was observed, there is photographic evidence of it. So the question isn't really if bowing occurred, but how. I am happy that at least you acknowledge there is a horizontal component to the force when the trusses sag. You mostly question if this force was strong enough, especially after connections failed. So since you also seem to reject the sagging trusses explanation, what do you think caused the bowing?