If the twin towers were left burning, could they soon collapsed?

I was thinking of putting up this question since we have this conspiracy theory about bombs or some type of explosives that were supposedly used in the towers to take it down. Now my question is, if the towers were left burning, could the towers sooner or later collapsed without the need for explosives? Since there was no way to put the fire out that was extremely hot and that is beyond the reach of the most capable of fire fighting systems and tools.

Yes fire could of brought down the towers, its true it takes like 1200 degrees to melt steel and the fires were only burning at around 800 degree's but guess what steel loses about half its strength at about 600 degree. So the top bunch of floors collapse and bring down the rest.

I submit to you the popular mechanics debunking of the conspiracy

Popular Mechanics

Thats what happened. Maybe you saw it on T.V. It was in all the papers.

Just kidding. Do you mean JUST the fires? It would have been so damaged that it probably have to be demolished. Since 110 stories is beyond a CD even without considering the damage and any prefailing would probably make the building to unstable in the wind loads at that height, it would probably have to me taken down manually to a point where a CD would be feasible. Just my 2 cents.

[edit on 28-7-2006 by Vushta]

So if the towers weren't brought down with explosives, it had to be fire.

Actually, the official reports say the towers held up for longer than expected, considering the circumstances they weren't designed for.

Twin Towers showed 'remarkable' resistance

Twin Towers 'never fire-tested'

No.

www.911research.com...

I would say no as well.

There was an uncontrolled fire much lower in Building One in 1976. It was set by an arsonist janitor, and was pretty severe. Flames coming out of windows, took some hours to control. And this was before fireproofing and all of that had been installed.

After it was all said and done, no steel had to be replaced. The structure was perfectly. fine.

The only difference with 9/11 was that it was higher up and a plane had also crashed into the building. So there was already some damage there, but the fires still had their work cut out for them, because the structural damage from the impacts wasn't that much compared to what was still left standing.

Planes knocked out less than 15% of the perimeter columns, probably less of the core though no one went in to check. That buildings could've taken about 75% total column loss on any given floor before the whole floor would give way, columns and all. That leaves about >60% for the fires. Like I said, they would've had their work cut out for them. And they apparently only needed less than 2 hours in either building.


Also, should trusses have failed, I don't think even a local collapse would have initiated.


But if a local collapse had initiated, I think it would've come to a halt in between 3 and 10 floors down, easily. Or else the tilting section would've partially collapsed over the side (WTC2), or both.


In no case should the buildings have behaved as they actually did on 9/11, without explosives being used to aid the collapses, imo.

Originally posted by JackJuice
Yes fire could of brought down the towers, its true it takes like 1200 degrees to melt steel and the fires were only burning at around 800 degree's but guess what steel loses about half its strength at about 600 degree.

Not quite that much. At 600 degrees F it drops to about 77% of its original strength.

[edit on 7-29-2006 by Valhall]

I think he meant Celsius, which would be half loss.

The problem is that there is no evidence anything was ever heated that much. Those fires were probably no hotter than 700 C max given the ventilation and how black the smoke was, and that 700 C would NOT be transferred directly to the steel. Very little of the heat would, compared to total output, due to it being carried away by the smoke (black smoke has a very high thermal capacity), being absorbed and carried away by the nearby clearer air/atmosphere/etc., the concrete slabs, everything in the offices, etc.

How much of that heat would make it to the steel? And then, how much would stay? Steel is very efficient at transferring heat, at "wicking it away" as Prof. Jones puts it, so that the heat spreads and the temperatures are thinned between all of the connected columns and trusses.

Also, there is no photographic evidence of steel getting even near that hot, as it begins to glow in broad daylight. There are photographs from all during the fires, and the only glowing metal was the bright yellow, molten material pouring out of the corner of WTC2, which was probably a thermite reaction taking place behind a column section that no longer existed (broken corner box column). Nothing else would explain why it was glowing so brightly, be it aluminum or steel or what-have-you.

Also, should trusses have failed, I don't think even a local collapse would have initiated.

How would that work?

Without the bracing system connecting the core to the perimeter creating a wide enough footprint for the height, I seriously doubt if the core could have stood by itself with no damage of any kind.

Correct me if I'm wrong, but I think the sections of steel were little more than tack welded and were kept in place vertically by compression in the completed structure and the stability came from the bracing of the trusses and the spandrel system.

[edit on 29-7-2006 by Vushta]

"I have never seen melted steel in a building fire," says retired New York deputy fire chief Vincent Dunn, author of The Collapse Of Burning Buildings: A Guide To Fireground Safety. "But I've seen a lot of twisted, warped, bent and sagging steel. What happens is that the steel tries to expand at both ends, but when it can no longer expand, it sags and the surrounding concrete cracks."

If steel didn't warp twist and otherwise get weak when exposed to large fires then there would be no need for the fireproof insulation that they put around the steel. You see in a large buidling the steel isn't all of the strength. It is also combined with concrete and when the steel expands from heat and twists it cracks and breaks apart that concrete.

But jet fuel wasn't the only thing burning, notes Forman Williams, a professor of engineering at the University of California, San Diego, and one of seven structural engineers and fire experts that PM consulted. He says that while the jet fuel was the catalyst for the WTC fires, the resulting inferno was intensified by the combustible material inside the buildings, including rugs, curtains, furniture and paper. NIST reports that pockets of fire hit 1832°F.

"The jet fuel was the ignition source," Williams tells PM. "It burned for maybe 10 minutes, and [the towers] were still standing in 10 minutes. It was the rest of the stuff burning afterward that was responsible for the heat transfer that eventually brought them down."

I submit my source again as the Popular Mechanics article.

Originally posted by Vushta
Without the bracing system connecting the core to the perimeter creating a wide enough footprint for the height, I seriously doubt if the core could have stood by itself with no damage of any kind.

I don't, and I think it's ridiculous that anyone actually thinks the core could not stand on its own.

The perimeter columns were not holding the core up -- that's ass backwards. The core structure was the gravity-bearing structure. It was built solely to carry the gravity loads. All of the trusses and perimeter columns could've collapsed around it, and it would have stood just fine, unless a hurricane suddenly broke out. Then it would fail, because its ability to withstand strong winds (or heavy lateral loads) would have been lost, as they were provided by the perimeter columns.

The perimeter columns were also linked together in three by spandrel plates, so if perimeter columns were lost above, the lower ones would stand perfectly fine (see impact holes for an example).

Again, localized failures.

Really -- if truss failure theory is correct, why didn't the towers collapse immediately after impact? More trusses and perimeter columns failed then than would fail during ALL of the fires, up until each collapse.



JackJuice -- It is a fact that steel will lose only half its strength when heated all the way to 600 C, which is hard to accomplish. Virtually no strength loss until approaching 600 C. Why the fireproofing? Overkill, and we'd had people post in the past that worked for companies that dealt with fireproofing applications, and they've even said themselves that it really was more bureaucratic than practical.

Kind of like telling kids to duck under their desks if a nuke went off. We did that in the 1960s, of course, but what would it have really accomplished?

And the PM article is outdated. See here: 911review.com...

[edit on 29-7-2006 by bsbray11]

July 2006 and people are still using popular mechanics as a source? Where's my Delorean?

something to get you started:
911research.wtc7.net...
www.911review.com...

If steel didn't warp twist and otherwise get weak when exposed to large fires then there would be no need for the fireproof insulation that they put around the steel. You see in a large buidling the steel isn't all of the strength. It is also combined with concrete and when the steel expands from heat and twists it cracks and breaks apart that concrete.

Interesting part "large fires". Apparantly absent on september 11.
Or are we gonna create evidence just because we need it to fit our explanation?

Tons and tons of RELIABLE sources and people are still using this crap?

911research.wtc7.net...
www.911review.com...


hmmmm........

Yes, and in fact, more and more people are starting to see that these sources hold more ground. I can't say that's the same for the popular mechanics article.

But hey, apparantly your view of a reliable source is one filled with lies and distractions so we can discuss this till eternity.

Well, I guess we'll have to agree to disagree on that one.
I just can't see how how a structure 1330 feet tall could stand on the size footprint that just the core provided. There was a constant though variable wind load. It just doesn't wash for me.

Really -- if truss failure theory is correct, why didn't the towers collapse immediately after impact? More trusses and perimeter columns failed then than would fail during ALL of the fires, up until each collapse.

The damage from the collision was still within the structural limits.



The perimeter columns were also linked together in three by spandrel plates, so if perimeter columns were lost above, the lower ones would stand perfectly fine (see impact holes for an example).


Thats true for the intact system of the design.

If my truss failure theory is correct, what does that do to your theory?

[edit on 29-7-2006 by Vushta]

Vushta, the core's relative thinness is the only reason you can't see it standing on its own, then how does this structure stand?


en.wikipedia.org...

That's the tallest structure in the world. It's 2,063 feet tall.

Just because a structure is relatively thin (though the cores were not NEARLY that thin) does not mean it will not stand on its own.

Originally posted by Vushta
If my truss failure theory is correct, what does that do to your theory?

Show me enough pre-collapse buckling to actually lend support to your theory and I'll answer you.

That tower is not standing on its own.

The actual footprint for the tower is represented by the distance of the cables staked out that give it its stability. The footprint is very wide.

Show me enough pre-collapse buckling to actually lend support to your theory and I'll answer you.

O.K....but first, so we just don't waste each others time.
How much is 'enough' for you? How did you determine this?

Apparently my source is old so therefore no good how about another

The additional problem was distortion of the steel in the fire. The temperature of the fire was not uniform everywhere, and the temperature on the outside of the box columns was clearly lower than on the side facing the fire. The temperature along the 18 m long joists was certainly not uniform. Given the thermal expansion of steel, a 150°C temperature difference from one location to another will produce yield-level residual stresses. This produced distortions in the slender structural steel, which resulted in buckling failures. Thus, the failure of the steel was due to two factors: loss of strength due to the temperature of the fire, and loss of structural integrity due to distortion of the steel from the non-uniform temperatures in the fire.

My source is Here

The fact of the matter is, that all of this conspiracy stuff it seems to me is becoming a sort of religion. What happens is that people believe false or incomplete evidence with out independant research into the matter. Its almost as if people want to believe that the government is evil and responcible for this. Now it is a fact that Western society has a ingrained mistrust of goverment. While i find the whole conspiracy apalling i am glad to see this mistrust of government still exists in our society for that is the best way to keep a government in check.

Ah, you're right. I didn't really notice in the pictures until you pointed that out.


Hmmmm...... Well there's the CN Tower, which is freestanding and 1815 feet high.



Really I'm just browsing Wikipedia for these, as examples, with the point being that tall, thin structures can stand under their own weight. Given, the WTC Towers' cores would not have been able to stand high winds, which, I would imagine, is the same reason the above mast is supported by wires.

Also remember these:





Which show cores, or sections of cores, standing after the rest of their respective towers had fallen. Rather than falling to the side, both of those also fell straight down upon themselves as if the bases had been blown out with explosives.