Professor thinks bombs, not planes, toppled WTC

[mack_the_knife]

Besides, jet fuel is just diesel, right? Oily, not very high octane, not really explosive, you know, just flammable. An hour later, it'd all be long gone.

It's more like kerosene, deisel is, as you say, not very explosive at all, you can even snuff out smokes in it pretty safely. However kerosene has a low flash point, similar to gasoline, and pound for pound more explosive capability. (why it is used in weight-critical applications).

 

[zeb1094]

I can't extrapolate the reaction pf the WTC structure to fire stress by looking at the way it was built. But Colleen is correct to say that collapsing vertically is always better than toppling, when you talk something as tall as those towers.

The slabs (that is, each massive floor) may have finished in narrow steel elements near the walls? In the early XX century, the building style called 'fireproof construction' had every floor joist narrow down near the place where they socket onto the masonry shell, in order to have a thin and weak spot at the wall. That way the thin wood right there at the join was to have burned through and have allowed the floor to fall down, preserving the masonry shell and avoiding torsional stress on the masonry.

But looking at the construction of the WTC towers, I still do not see the place which would have been designed to fail. Besides, jet fuel is just diesel, right? Oily, not very high octane, not really explosive, you know, just flammable. An hour later, it'd all be long gone. The stuff burning an hour later would be rugs, insulation, office furniture, all the usual fire load.

Tall, tall buildings like skyscrapers have to consider wind loads, too. The Towers would have been built to sway, to yield somewhat to the wind. That elasticity would have helped them withstand the lateral impact of the airplane, by letting them bend and come back. They did not topple over sideways as a result of the lateral force of impact, but collapsed straight down an hour and a quarter (in one case) and something like three quarters of an hour (n the other) after the airplanes hit. So it was the fire, in some way. But there have been damn few skyscraper failures from fires. They are designed to withstand fires.

Tower 7 was blown up deliberately, wasn't it? Because it was a hazrd?

Clearification point: Jet Fuel is not anything like Diesel, it's either JP4 or JP5, which if stepped on the wrong way can burst into flame. The heat from a running truck engine can cause ignition, no spark needed.

 

[elsol]

Can someone check if this guy is a part of the Flat Earth Society...

It would explain a lot.

A FUCKING AIRLINER HIT THE GODDAMN BUILDING!!!

For all the conspiracy whackos... if the government knew about the fucking airplanes before hand, enough to put the bombs in place... WHY PUT THE BOMBS IN PLACE?!?

You risk more by doing that... in a risk/gain game... doing nothing has plausible deniablity.

Planting bombs is adding a fuck of a lot of risk for little to no gain.

Whether the towers came down or not... we were going to kick the shit out of somebody.

Come on, jerkoffs! If you give the conspirasists enough credit to pull this shit off, they're fucking certainly smart enough to properly weigh the best risk/gain scenarios and arrive at 'Do nothing.'


Sincerely,
ElSol

 

[cantdog]

Cool down, el sol, old fruit! Who you talkin' to? None of us here has bought the 'conspiracy' thing, right?

Wo, hoss.

 

[elsol]

Cool down, el sol, old fruit! Who you talkin' to? None of us here has bought the 'conspiracy' thing, right?

Wo, hoss.

I'm sure theirs a few lurking about

There always are.

--It's my personal conspiracy thing.

Sincerely,
ElSol

 

[mack_the_knife]

I'm sure theirs a few lurking about

There always are.

--It's my personal conspiracy thing.

Sincerely,
ElSol

There's a couple hiding behind that *other* NaNo thread.

 

[SeaCat]

Okay, a little information that I found while searching. The fuel normaly carried aboard an airliner is something called Jet-A. It is almost pure kerosene. It has a flashpoint of 120°F and an Autoignite temp of 800°F+. (Sorry I couldn't find any information on just how hot this stuff burns but rest assured it is hot.)

Would the amount of fuel carried in an aircraft burn hot enough and long enough to weaken the steel structural members of a building like this to start a pancake effect? More than just likely.

You have to remember that the fire retardant coating on steel stops it from burning, at least for a little while. (Yes Virginia there is a Santa Clause and anything will burn if you get it hot enough.) It doesn't do a whole lot for stopping heat transfer though. You don't have to cause the steel to burn, just heat it enough that it will weaken, lose it's structural integrity. (Hey you can do that with a blowtorch remember?) How much heat is needed? Just enough to get it soft enough for the weight of the floors to make it bend.

Yes there was structural damage to the buildings from getting hit, but not enough to cause a collapse. (Remember these building were actually built with that in mind. They were built after the Empire State Building got hit.) How much did the actual impacts damage the towers, and did this help in them coming down? To the first we may never know. To the second, the flippant answer is it sure didn't help them stay up.

Cat

 

[cantdog]

Clearification point: Jet Fuel is not anything like Diesel, it's either JP4 or JP5, which if stepped on the wrong way can burst into flame. The heat from a running truck engine can cause ignition, no spark needed.

Yeah, trucks use glow plugs, dude. It's kero, it's oily, it aint gasoline, iit ain't ether. Kerosene burns, but it is hard to get an explosion out of it. Brits call it paraffin.

It's not as volatile as gasoline (petrol); less vaporizing, more penetration. Makes it a good accelerant choice because it soaks in. tens of thousands of gallons of it. That ought to be enough, don't you think? Painting jet fuel as though it were a step below nitro is just ridiculous. Step on it the wrong way, my ass.

I did crash rescue, we trained with this stuff. It's kerosene.

 

[zeb1094]

Yeah, trucks use glow plugs, dude. It's kero, it's oily, it aint gasoline, iit ain't ether. Kerosene burns, but it is hard to get an explosion out of it. Brits call it paraffin.

It's not as volatile as gasoline (petrol); less vaporizing, more penetration. Makes it a good accelerant choice because it soaks in. tens of thousands of gallons of it. That ought to be enough, don't you think? Painting jet fuel as though it were a step below nitro is just ridiculous. Step on it the wrong way, my ass.

I did crash rescue, we trained with this stuff. It's kerosene.

And just how many flight lines have you walked on. How much training have you had on the proper care and handling of JP4 or JP5. I have had over one hundred hours of training on the care and handling of a fuel spill. The first thing we were taught was 'please don't walk on the spilled jet fuel' and 'please don't drive your truck or car through the jet fuel' unless you would like to hear that ringing in your ears that will signal you that you whole day is about to be ruined.

 

[cantdog]

Fine, have it your way.

I waded in the shit with live flames playing around me.

Please don't try to use kerosene lamps.

 

[Colleen Thomas]

Jet fuel is closer to kerosine than diesle. And it isn't all that much more explosive than gasoline. What it does do, is burn hot and pound for pound of volume, it gives off more energy when burned.

At the bottom line, it will not burn hot enough to melt steel no matter how much you have or how you set it off in a diffuse situation. This is much like alcohol rocket fuel, alone it won't make your rocket go very far or very fast, it simply burns too slow. You can get jet fuel to burn hot enough to melt steel, provided you are using the proper additive (usualy liquid oxygen) in the proper measure, and in a controled situation. None of that exists in a free burn.

So the supposition the jet fueld fires melted the steel is simply not feasible. But, and it's the crux of it, you need significantly less heat to weaken structural steel. less than half the heat in fact. And in the case of a building like the world trade centers, you don't even need that much, because you aren't trying to weaken the Ibeams, just the clips that hold the floor decking to the I-beams.

Each floor was steel decking, covered in concrete. And ten of them weighted on the order of 41,000 pounds not including the things sitting on them like deks and file cabnets, etc. The steel clips, are therefore, already under stress, just holding up the floors. In any tall building the major stressor is gravity and that means the major forces are verticle forces. The only real lateral stressor engineers deal with is wind.

Each floor, theoretically can support the weight of the floor, plus the weight of the things on that floor. Further, each floor can support at least part of the weight of the floor above it, in an emegerncy. If more than one floor fails, however, you get a chain reaction, as each successive floor is subjected not only to accumulated weight, but to accumulated force, provided via gravitation acceleration of the whole mass.

the only real question then, is if 90,000L of aviation fuel will burn hot enough, long enough, to cause structural steel to deform. i haven't seen any valid, scientific documentation to say it won't. Once the failure begins, simple physics explain the rest.

F = ma

Force, equals mass times acceleration. In free fall, gravitational acceleration is a constant 9.8 m/second squared I think. The mass is significant, one floor coming in around 4100 pounds. In a ten foot drop, it has already gained a significant amount of force. Without doubt enough to test the limits of the clips holding the floor below it to the frame. If those clips have already been weakened by fire and give, you not only double the mass coming down, you give the entie thing another ten feet of acceleration. At that point F has become greater than the clips in perfect condition can support.

*the 41,000 may well be tons instead of pounds, I can'tt ell from the articles I have read.

**the 90,000L of jet fuel is also the high end, the capacity of the combined tanks of the liners that hit. Obviously not all of it was released into the buildings.

***the black smoke coming out of the buildings indicates the fuel was burning in a diffuse state, not fully oxidizing.

 

[Joe Wordsworth]

So, when I read the University of Sydney's breakdown on the construction of the WTC and its collapse, from its Civil Engineering essays, which said...

"The structural integrity of the World Trade Center depends on the closely spaced columns around the perimeter. Lightweight steel trusses span between the central elevator core and the perimeter columns on each floor. These trusses support the concrete slab of each floor and tie the perimeter columns to the core, preventing the columns from buckling outwards.

After the initial plane impacts, it appeared to most observers that the structures had been severely damaged, but not necessarily fatally.

It appears likely that the impact of the plane crash destroyed a significant number of perimeter columns on several floors of the building, severely weakening the entire system. Initially this was not enough to cause collapse.

However, as fire raged in the upper floors, the heat would have been gradually affecting the behaviour of the remaining material. As the planes had only recently taken off, the fire would have been initially fuelled by large volumes of jet fuel, which then ignited any combustible material in the building. While the fire would not have been hot enough to melt any of the steel, the strength of the steel drops markedly with prolonged exposure to fire, while the elastic modulus of the steel reduces (stiffness drops), increasing deflections.

Modern structures are designed to resist fire for a specific length of time. Safety features such as fire retarding materials and sprinkler systems help to contain fires, help extinguish flames, or prevent steel from being exposed to excessively high temperatures. This gives occupants time to escape and allow fire fighters to extinguish blazes, before the building is catastrophically damaged.

It is possible that the blaze, started by jet fuel and then engulfing the contents of the offices, in a highly confined area, generated fire conditions significantly more severe than those anticipated in a typical office fire. These conditions may have overcome the building's fire defences considerably faster than expected. It is likely that the water pipes that supplied the fire sprinklers were severed by the plane impact, and much of the fire protective material, designed to stop the steel from being heated and losing strength, was blown off by the blast at impact.

Eventually, the loss of strength and stiffness of the materials resulting from the fire, combined with the initial impact damage, would have caused a failure of the truss system supporting a floor, or the remaining perimeter columns, or even the internal core, or some combination. Failure of the flooring system would have subsequently allowed the perimeter columns to buckle outwards. Regardless of which of these possibilities actually occurred, it would have resulted in the complete collapse of at least one complete storey at the level of impact.

Once one storey collapsed all floors above would have begun to fall. The huge mass of falling structure would gain momentum, crushing the structurally intact floors below, resulting in catastrophic failure of the entire structure. While the columns at say level 50 were designed to carry the static load of 50 floors above, once one floor collapsed and the floors above started to fall, the dynamic load of 50 storeys above is very much greater, and the columns were almost instantly destroyed as each floor progressively "pancaked" to the ground."

...I'm to take it that they are incorrect because jet fuel can't have done that and the building needed bombs to drop it? Is that about, generally, what we're saying?

 

[cantdog]

No, all it is? We got a guy who doesn't see the above analysis as sufficient. He wants to have us imagine that jet fuel is some sort of highly explosive liquid. Whereas, tens of thousands of gallons of it is a great plenty to get a fire going; you don't have to exaggerate.

A vast explosion would have had a more immediate effect. The towers stood for about an hour each. It was, rather, as in the analysis you cite, fire softening the steel, over time. Jet fuel isn't nitro, and it doesn't have to be.

How's the corporate world, Joe?

 

[cantdog]

Colleen, You don't have to melt the steel, just soften it. Bar joists, which are lightweight-steel trusses used as floor supports, fail this way routinely in ordinary structure fires. The steel doesn't melt, it heats and becomes less rigid.

 

[zeb1094]

No, all it is? We got a guy who doesn't see the above analysis as sufficient. He wants to have us imagine that jet fuel is some sort of highly explosive liquid. Whereas, tens of thousands of gallons of it is a great plenty to get a fire going; you don't have to exaggerate.

A vast explosion would have had a more immediate effect. The towers stood for about an hour each. It was, rather, as in the analysis you cite, fire softening the steel, over time. Jet fuel isn't nitro, and it doesn't have to be.

How's the corporate world, Joe?

I never said anything about explosions, I said, and maybe not clearly enough, that Jet Fuel has a low flash point (ie. Jet-A flash point 120 derees F) which means it will started to burn at that temperature or above. It will not explode unless it is confined in a small area and has time to vaporize. As with gasoline, it the vaporous form that is explosive. The liquid form will just flare up and burn and burn hot.

 

[BlackShanglan]

Speaking of weight, I don't imagine that most of the floors of the WTC were designed to support the additional weight of the better part of a commercial jetliner and 90,000l of jet fuel, either. Not, obviously, that the other elements cited weren't more than adequate to explain the collapse, but might as well make sure that we don't forget the obvious. I don't know what a liter of jet fuel weighs in at, but surely we're looking, with the figure of 90,000 liters, at quite a few tons?

Shanglan

 

[Joe Wordsworth]

No, all it is? We got a guy who doesn't see the above analysis as sufficient. He wants to have us imagine that jet fuel is some sort of highly explosive liquid. Whereas, tens of thousands of gallons of it is a great plenty to get a fire going; you don't have to exaggerate.

A vast explosion would have had a more immediate effect. The towers stood for about an hour each. It was, rather, as in the analysis you cite, fire softening the steel, over time. Jet fuel isn't nitro, and it doesn't have to be.

How's the corporate world, Joe?

Challenging and fun, I like money and I like the making of and playing with money--and in a big corporate environment, I get to have direct control over more variables than I did in previous professions. My package includes 10% of whatever's put on the bottom line every month, so the better I play the game, the higher my score--so to speak.

As for the WTC, I didn't know it was in contention. Shows how little I was paying attention.

 

[elsol]

"Pluralitas non est ponenda sine neccesitate"


An airliner hit the building.
This caused what could be described as an inferno... considering people JUMPED rather than stay in ze inferno, I would say it was pretty fucking hot.

This professor is a shithead... I don't think we need to prove it, but it seems to me this requires a single leap of logic rather than anything 'sine neccesitate'.

Sincerely,
ElSol

 

[SeaCat]

Jet fuel is closer to kerosine than diesle. And it isn't all that much more explosive than gasoline. What it does do, is burn hot and pound for pound of volume, it gives off more energy when burned.

At the bottom line, it will not burn hot enough to melt steel no matter how much you have or how you set it off in a diffuse situation. This is much like alcohol rocket fuel, alone it won't make your rocket go very far or very fast, it simply burns too slow. You can get jet fuel to burn hot enough to melt steel, provided you are using the proper additive (usualy liquid oxygen) in the proper measure, and in a controled situation. None of that exists in a free burn.

So the supposition the jet fueld fires melted the steel is simply not feasible. But, and it's the crux of it, you need significantly less heat to weaken structural steel. less than half the heat in fact. And in the case of a building like the world trade centers, you don't even need that much, because you aren't trying to weaken the Ibeams, just the clips that hold the floor decking to the I-beams.

Each floor was steel decking, covered in concrete. And ten of them weighted on the order of 41,000 pounds not including the things sitting on them like deks and file cabnets, etc. The steel clips, are therefore, already under stress, just holding up the floors. In any tall building the major stressor is gravity and that means the major forces are verticle forces. The only real lateral stressor engineers deal with is wind.

Each floor, theoretically can support the weight of the floor, plus the weight of the things on that floor. Further, each floor can support at least part of the weight of the floor above it, in an emegerncy. If more than one floor fails, however, you get a chain reaction, as each successive floor is subjected not only to accumulated weight, but to accumulated force, provided via gravitation acceleration of the whole mass.

the only real question then, is if 90,000L of aviation fuel will burn hot enough, long enough, to cause structural steel to deform. i haven't seen any valid, scientific documentation to say it won't. Once the failure begins, simple physics explain the rest.

F = ma

Force, equals mass times acceleration. In free fall, gravitational acceleration is a constant 9.8 m/second squared I think. The mass is significant, one floor coming in around 4100 pounds. In a ten foot drop, it has already gained a significant amount of force. Without doubt enough to test the limits of the clips holding the floor below it to the frame. If those clips have already been weakened by fire and give, you not only double the mass coming down, you give the entie thing another ten feet of acceleration. At that point F has become greater than the clips in perfect condition can support.

*the 41,000 may well be tons instead of pounds, I can'tt ell from the articles I have read.

**the 90,000L of jet fuel is also the high end, the capacity of the combined tanks of the liners that hit. Obviously not all of it was released into the buildings.

***the black smoke coming out of the buildings indicates the fuel was burning in a diffuse state, not fully oxidizing.

Colleen,

Thanks for the additional info.

Cat

 

[Colleen Thomas]

Colleen,

Thanks for the additional info.

Cat

You're welcome cat.

What's really amazing to me is that someone like myself, with only a college level education in science with about ten minutes of searching on the web, can see what a load of crap this theory is.

It dosen't take a genius to realize if you suspend half a million tons vertically, it wants to come down. Remedial knowledge of structural engineering makes it plain that buildings, when they come down, are designed to come down in place.

If I were the dean pr college president, I would be looking for a way to get this idiot off of my staff.

 

[Pure]

Questions

The prof may be way off, but anyone reading a timeline for 9-11 cannot help but have questions, for example regarding scrambling of fighters (e.g., to defend Washington DC targets), notification of Norad, notification of FAA, etc.

There is a good timeline at

http://www.cooperativeresearch.org/timeline.jsp?timeline=complete_911_timeline&day_of_9/11=dayOf911

In brief, first tower hit 8:45; second hit 9:00; pentagon hit 9:40; plane plunges to ground in PA, possibly on way to White House, 10:06.

One does have to keep in mind the maxim that it's most often human bungling rather than conspiracy.

 

[cantdog]

I always figured they shot down the 'plane in PA. Didn't you?

 

[SeaCat]

I always figured they shot down the 'plane in PA. Didn't you?

Nope, I would have heard about it by now. (Friends in low places you know.)

Cat

 

[SeaCat]

You're welcome cat.

What's really amazing to me is that someone like myself, with only a college level education in science with about ten minutes of searching on the web, can see what a load of crap this theory is.

It dosen't take a genius to realize if you suspend half a million tons vertically, it wants to come down. Remedial knowledge of structural engineering makes it plain that buildings, when they come down, are designed to come down in place.

If I were the dean pr college president, I would be looking for a way to get this idiot off of my staff.

Colleen,

Like Cant I have a little experience in some of this. (Volunteer Firefighter for more than a couple of years.) It's absolutlely amazing at what people don't know, and what people who should know will come up with.

Yes, Like Cant I have played with aircraft fuels of all kinds. Sometimes in controlled environments, and occasionally in uncontrolled environments.

Like I said in my last post, and Cant also said. It doesn't have to burn long enough or hot enough to actually melt the steel, just long enough and hot enough to start the process. Once the Steel is weakened by the heat it's all over. It starts to bend, it has lost it's tructural integrity. (Cant and I have both seen this in smaller house fires.) People would be amazed at just how much heat steel will transmit. The floor around a steel plate will not even be warm to the touch but the plate will burn the hell out of you. (BTDT)

What amazes me about the article is that no one has seen fit to argue with this professor. He seems to have absolutley no knowledge of the things he needs to know to back up his article.

Cat

 

[Colleen Thomas]

Colleen,

Like Cant I have a little experience in some of this. (Volunteer Firefighter for more than a couple of years.) It's absolutlely amazing at what people don't know, and what people who should know will come up with.

Yes, Like Cant I have played with aircraft fuels of all kinds. Sometimes in controlled environments, and occasionally in uncontrolled environments.

Like I said in my last post, and Cant also said. It doesn't have to burn long enough or hot enough to actually melt the steel, just long enough and hot enough to start the process. Once the Steel is weakened by the heat it's all over. It starts to bend, it has lost it's tructural integrity. (Cant and I have both seen this in smaller house fires.) People would be amazed at just how much heat steel will transmit. The floor around a steel plate will not even be warm to the touch but the plate will burn the hell out of you. (BTDT)

What amazes me about the article is that no one has seen fit to argue with this professor. He seems to have absolutley no knowledge of the things he needs to know to back up his article.

Cat

I'm not sure what I said that gave the impression I thought melting was neccessary. I was trying to say, the commonly held perception it was was erroneous and that you only had to apply enough heat to make the steel begin to deform to have the structure fail.