World Trade Center Construction Flaws Revisited

[dchan]

Originally Posted by THE BIG APPLE

The steel rolling process is conducted under very high temperatures to carve the steel. Ok lets get off the concrete building and steel building topic and off the Windsor Tower topic. Lets go back to February 13, 1975 when the North Tower sustained a three alarm fire. I'm sure there were desks and papers on the 10th-14th floors. Why did the building not fall in 1975. I mean it was on the lower floors, so how come the building didn't give way then.

The collision of the planes to both towers exposed much of the bare steel to the surface by obliterating the weak spray-on fireproofing and the drywall boards. The WTC steel deformed not only because of the heat from the fire, but also because it no longer had fireproofing and drywall insulating it against the fire.

You also forget a key component of the 9/11 fire - jet fuel. By itself, it doesn't burn a extremely high temperatures unless pressurized and sent through a nozzle (like in a jet engine). But it does add a significant source of combustion fuel to the existing sources of combustion within the building, with which it generates incredibly intense heat that can compromise bare structural steel's integrity. (And remember - this is heat we're talking about, not temperature. Two different concepts in thermodynamics.)

And a typical office fire can be controlled, and the fire from 1975 sounded no different (considering that it was put out, and the building was eventually occupied and in good condition). The fireproofing insulation on the steel remained intact, as well as the drywall insulation covering up the core. This alone prevented the fire from weakening the steel. Combined with the fact that tons of jet fuel was not involved in the fire, and you have a far, far more controllable fire than the inferno on 9/11.

[wong21fr]

^Let's see:

-The fire was mainly limited to one floor.

-It was a single source ignition that slowly spread.

-Fire mitigation measure, i.e. fireproofing on the beams, were present.

-The fire was actively fought from the beginning with firefighters being able to use water lines and such.

-A 300,000-odd pound jet airliner didn't crash into the building at 500-plus miles per hour.

[THE BIG APPLE]

Originally Posted by dchan

The collision of the planes to both towers exposed much of the bare steel to the surface by obliterating the weak spray-on fireproofing and the drywall boards. The WTC steel deformed not only because of the heat from the fire, but also because it no longer had fireproofing and drywall insulating it against the fire.

You also forget a key component of the 9/11 fire - jet fuel. By itself, it doesn't burn a extremely high temperatures unless pressurized and sent through a nozzle (like in a jet engine). But it does add a significant source of combustion fuel to the existing sources of combustion within the building, with which it generates incredibly intense heat that can compromise bare structural steel's integrity. (And remember - this is heat we're talking about, not temperature. Two different concepts in thermodynamics.)

And a typical office fire can be controlled, and the fire from 1975 sounded no different (considering that it was put out, and the building was eventually occupied and in good condition). The fireproofing insulation on the steel remained intact, as well as the drywall insulation covering up the core. This alone prevented the fire from weakening the steel. Combined with the fact that tons of jet fuel was not involved in the fire, and you have a far, far more controllable fire than the inferno on 9/11.

You're calling the small scattered fires on 9/11 an inferno. What happened to the Windsor Tower was an inferno. Since jet fuel is a kerosene type fuel how come the steel on a kerosene heater doesn't melt. The fire on 9/11 was red-orange indicating it was around 1,500 F. Mixed with jet fuel the maximum the temperature of the fire could have gone up to was 1,900 F or 400 more degrees. Still not hot enough to completely melt steel, but capiable of making the steel loose some of its strength. 400 F is the maximum jet fuel can take a normal office fire temperature up by. I got one question for you if the fires combined with the jet fuel were really that high in temperature then how come three people from the impact zones survived and were not burned by the intense heat (inferno) as you like to call it. One key survivor Stanley Praimnath saw the planes coming and he hid under his desk. The jet fuel and fire (inferno) surely should've cooked this survivor alive, and he wouldn't be able to tell his story. My point is the fires were not even close to an inferno, so get off that topic.

[hammersklavier]

I just want to confirm something I've always thought: I noticed the plane did not hit Tower 2 dead-on the way Tower 1 was hit, and in fact hit at an angle. I've always wondered whether this slight angle was enough to unbalance the load of the structural steel enough (combined with the other elements of the inferno, of course) to cause the building to fail? After all, Tower 2 was hit later yet fell first...

[dchan]

Originally Posted by THE BIG APPLE

You're calling the small scattered fires on 9/11 an inferno. What happened to the Windsor Tower was an inferno. Since jet fuel is a kerosene type fuel how come the steel on a kerosene heater doesn't melt. The fire on 9/11 was red-orange indicating it was around 1,500 F. Mixed with jet fuel the maximum the temperature of the fire could have gone up to was 1,900 F or 400 more degrees. Still not hot enough to completely melt steel, but capiable of making the steel loose some of its strength. 400 F is the maximum jet fuel can take a normal office fire temperature up by. I got one question for you if the fires combined with the jet fuel were really that high in temperature then how come three people from the impact zones survived and were not burned by the intense heat (inferno) as you like to call it. One key survivor Stanley Praimnath saw the planes coming and he hid under his desk. The jet fuel and fire (inferno) surely should've cooked this survivor alive, and he wouldn't be able to tell his story. My point is the fires were not even close to an inferno, so get off that topic.

Please read the other source on "The Fire", which discusses the difference between temperature and actual heat (and I don't say "please read it again", because I know you haven't). Then we can talk.

Also, stop referring to your chart because it's apparent that you don't know what it stands for.

[THE BIG APPLE]

Originally Posted by dchan

Please read the other source on "The Fire", which discusses the difference between temperature and actual heat (and I don't say "please read it again", because I know you haven't). Then we can talk.

Also, stop referring to your chart because it's apparent that you don't know what it stands for.

I know perfectly what it stands for, it's you who doesn't. I know papers, and desks blah blah blah. It's apparent your not reading my posts thoroughly, cause maybe then you'll learn something.

[dchan]

Originally Posted by THE BIG APPLE

I know perfectly what it stands for, it's you who doesn't. I know papers, and desks blah blah blah. It's apparent your not reading my posts thoroughly, cause maybe then you'll learn something.

Fine. You tell me what you think was the reason that led to the collapse of the towers. Right now, you're only a skeptic that tries to poke holes into others' arguments without coming up with your own argument.

So please, without further ado, present your argument.

[THE BIG APPLE]

Originally Posted by dchan

Fine. You tell me what you think was the reason that led to the collapse of the towers. Right now, you're only a skeptic that tries to poke holes into others' arguments without coming up with your own argument.

So please, without further ado, present your argument.

My argument is this. Do you really think 19 people living in caves can pass the largest security system in the world, and knock down the Twin Towers which were specifically built to stand up to 4 or 5 planes crashing into them each.

Atleast you and me have one thing in common, we love wrestling.

[dchan]

Originally Posted by THE BIG APPLE

My argument is this. Do you really think 19 people living in caves can pass the largest security system in the world, and knock down the Twin Towers which were specifically built to stand up to 4 or 5 planes crashing into them each.

Atleast you and me have one thing in common, we love wrestling.

Okay, you're a conspiracy theorist. I got that in your first post on this thread. That notwithstanding, please continue with your argument on what specifically caused the WTC towers to collapse. By that, I mean just some basic structural failure analysis, nothing fancy.

[Tom In Chicago]

[[[MODERATOR WARNING]]]

Conspiracy theories are not allowed on this forum. . . if you don't like it. . . find another message board that does. . .

. . .

[dchan]

Originally Posted by Tom In Chicago

[[[MODERATOR WARNING]]]

Conspiracy theories are not allowed on this forum. . . if you don't like it. . . find another message board that does. . .

. . .

That was quick. Does the forum actively screen for the term "conspiracy theorist"?

In any case, you can PM me your argument if you want, Big Apple.

[wong21fr]

Originally Posted by THE BIG APPLE

My argument is this. Do you really think 19 people living in caves can pass the largest security system in the world, and knock down the Twin Towers which were specifically built to stand up to 4 or 5 planes crashing into them each.

Damn, I never realized the old WTC was built with such robust survivability characteristics.... it's almost like they were a fortress.

Oh wait, that's factually incorrect. Like all conspiracy theories.

[THE BIG APPLE]

I've got places to go and people to see but I'm back. After a full page of unadultarated facts you people continue to be sheep. Well have at it, bacuase that's what I meant by thickheadedness when you refuse to believe the truth and continue to listen to the propaganda media that feeds you lies. Before this post gets deleted, I would like to start off by stating that I'm not a conspiracy theorist, but instead I believe in the truth. The truth is buildings can't fall from small fires. Please before anyone posts anything READ PAGE 2!

[Dense_Electric]

I harbor no illusions that any amount of science or logical reasoning is going to sway you (you're a conspiracy theorist, you've got your mind made up, and damned to hell if the facts are going to get in the way), but I must pose this rather glaring question to you:

Did you miss the part where a large commercial aircraft was flown through each building? The instant the aircraft penetrated the facade, literally the only thing holding the structure up, the building was compromised.

Having effectively removed about half of the supporting structure (as the weight was then being redistributed around the impact point through the columns that were still intact), the remaining supports were already under considerable stress. I believe I read somewhere that each building was rated to support something like 1300 tons above their existing weight per floor, with an existing weight of roughly 5000 tone per floor meaning (if my engineering is correct) that they could lose somewhere in the region of a third of their support columns and remain structurally sound. The aircraft impact on each building removed at least that much.

Now you throw in a fire. Understand, when they say steel must reach a certain temperature to melt, they mean reducing steel to molten slag. Obviously, you wouldn't have to go anywhere near that far, you merely have to structurally weaken it enough. Combine that with steel already weakened from structural overload, and you've got a recipe for failure.

Once those remaining supports went (in the large, outward plume of smoke and debris visible in the collapse videos), you had a hundred thousand tons of steel and concrete in free-fall, and once that hit the bottom of the impact zone, the portion of the building still intact wasn't going to stop it.

[dchan]

Originally Posted by THE BIG APPLE

I've got places to go and people to see but I'm back. After a full page of unadultarated facts you people continue to be sheep. Well have at it, bacuase that's what I meant by thickheadedness when you refuse to believe the truth and continue to listen to the propaganda media that feeds you lies. Before this post gets deleted, I would like to start off by stating that I'm not a conspiracy theorist, but instead I believe in the truth. The truth is buildings can't fall from small fires. Please before anyone posts anything READ PAGE 2!

Well then, just PM me what you believe is the truth, since the moderators will likely delete your anything they deem as "conspiracy theory". Explain to me in simple but moderate detail what you think brought about the collapse.

I'm looking at Page 2 of this thread (I assume that's what you're talking about), and you posted nothing but a steel temperature-color chart that has nothing to do with the color of a fire (that's what I think, what I believe most experts know) and a bunch of pictures that are supposed to support your suspicions. Of course, your suspicions are seemingly based on nothing but hopeful assumptions because you've haven't explained in any detail why you thought they were valid.

So please, if you truly believe in what you deem "the truth", PM me and perhaps we can discuss it in private.

[THE BIG APPLE]

Originally Posted by dchan

Well then, just PM me what you believe is the truth, since the moderators will likely delete your anything they deem as "conspiracy theory". Explain to me in simple but moderate detail what you think brought about the collapse.

I'm looking at Page 2 of this thread (I assume that's what you're talking about), and you posted nothing but a steel temperature-color chart that has nothing to do with the color of a fire (that's what I think, what I believe most experts know) and a bunch of pictures that are supposed to support your suspicions. Of course, your suspicions are seemingly based on nothing but hopeful assumptions because you've haven't explained in any detail why you thought they were valid.

So please, if you truly believe in what you deem "the truth", PM me and perhaps we can discuss it in private.

I posted MUCH more than that. I said READ CAREFULLY to everyone before you post. On page 2 I also stated the fact that if this was a pancake collapse and the floors on top gave way, nothing happened to the bottom portions of the towers, correct. So after everything should've been said and done, we should have seen floor on top of floor on top of floor on top of floor almost like a collection of your favorite cd's piled on top of each other. Instead what we saw was the buildings exploding when everyone said the buildings weakened to cause them to strucurally fail and implode. Implode and explode are two entirely different things, and I don't know if my eye sight is bad or yours is but on 9/11 we saw an explosion. So please READ page 2 CAREFULLY again cause' I posted much more than an ACCURATE chart. I'm not a crazy nutjob lunatic who is trying to change everyones mind, I'm JUST STATING FACTS.

[dchan]

Originally Posted by THE BIG APPLE

I posted MUCH more than that. I said READ CAREFULLY to everyone before you post. On page 2 I also stated the fact that if this was a pancake collapse and the floors on top gave way, nothing happened to the bottom portions of the towers, correct. So after everything should've been said and done, we should have seen floor on top of floor on top of floor on top of floor almost like a collection of your favorite cd's piled on top of each other. Instead what we saw was the buildings exploding when everyone said the buildings weakened to cause them to strucurally fail and implode. Implode and explode are two entirely different things, and I don't know if my eye sight is bad or yours is but on 9/11 we saw an explosion. So please READ page 2 CAREFULLY again cause' I posted much more than an ACCURATE chart. I'm not a crazy nutjob lunatic who is trying to change everyones mind, I'm JUST STATING FACTS.

Alright! Progress. Thanks for your explanation.

I don't know why you think it's an explosion. Perhaps it's because the collapse looked entirely different from the implosions that we're used to seeing in building demolitions. But the key here is to remember that carefully coordinated implosions are different from uncoordinated implosions. In controlled implosions, explosives are placed the key structural columns and supports. After they go off, the building comes down via gravity forces. The explosives are placed in a manner as to reduce the amount of debris and structure from landing anywhere else but straight down.

The WTC collapse, on the other hand, didn't rely on optimally placed explosives at key structural components. 2 planes crashed into the towers, destroying several perimeter and core columns, and subsequently igniting a giant office fire. As such, its collapse looked like no controlled implosion you've ever seen because, well, it wasn't a controlled implosion.

So to simply answer your question: yes, I believe it's an implosion, but one that relies on the dynamic relationship of the various components of the structural system of 2 crippled buildings. Structural engineers know how these structural components behave statically when they're standing and resisting gravity and wind loads, but they don't really know what's going to happen during, say, a jet crash into the building that compromises much of its structure and causes a giant fire. As the collapse occurs, structural dynamics takes over, and it's a far more complex subject, especially without all the variables known or available.

And you're not stating facts. Nor am I. We're both stating conjecture and opinions based on available facts and analysis. You're only conjecturing that a building is supposed to collapse like a stack of CDs. You're only opining that this was an explosion (BTW, wouldn't an explosion mean the debris would have scattered much farther? I think you still mean implosion via explosive devices). And I'm only opining my viewpoints.

And finally, your chart is indeed accurate. However, the way you use the chart is totally incorrect.

[scalziand]

Here's a chart from my steel textbook showing the weakening of steel when it is heated.


Steel Structural Design, 4th ed. McCormac

At 1100F the steel is at half strength, and very little strength is left beyond 1400F. Both are well below the melting temp of steel.

[GWHH]

The 110-story Twin Towers, built in the late 1960s, were radically different in structural design from conventional skyscrapers constructed up to that time. Since the 19th century, skyscrapers had been constructed with a skeleton of interior columns that supported the structure. The Towers, however, were constructed such that the outer walls—closely spaced vertical columns (59 columns on each face, spaced three feet, four inches apart) girdled by massive horizontal spandrels, tying the columns together—carried the buildings' vertical loads and provided the entire resistance to the wind. The only interior columns were in the core area, which contained the elevators and stairwells.

The floor sections consisted of lightweight, open-web steel trusses that spanned the core to the outer wall. The cylindrical, hollow steel truss members were between 11/2 and 15/8 inches in diameter. Truss spans were from 50 to 65 feet long without vertical support. The floors consisted of four-inch-thick lightweight concrete on a 11/2-inch, 22-gauge noncomposite steel deck.


http://www.fireengineering.com/artic...-response.html

http://www.fireengineering.com/artic...tc-towers.html

[GWHH]

The towers was desgin to surive a 707 impact. And there no inducations that the Designers even thought about looking into fuel load fires. Plus-all the orginals plans and paperwork related to the buidling. Was stored in the trade center complex and was destroyed on 9/11. They talked to all the people who worked on it and all of them said I did not do any calculations or even think about the fuel load of the planes.

A 767 is about TWICE the weight of a 707. According to the boeing website!

Originally Posted by Roadcruiser1

When the Twin Towers construction started in the 1960's the 747 was still on the drawing board, and therefore wasn't yet considered a threat. Also you have to consider that the engineers of the World Trade Center never thought that a plane would intentionally impact the Twin Towers. They thought that any impact would be an accident. They never thought that a Boeing 767 fully loaded with fuel would hit the building. After all they weren't fortune tellers.