the hidden history of 9/11

[mhgaffney]

Check out this excellent interview with Professor Paul Zarembka.

http://informationclearinghouse.info/article23122.htm

[spdirty]

did the Jews also fake the holocaust as well as invent the mininuke? Buy my book.

[Dukes]

Here's a news flash Gaff, nobody here gives a flying ****

[Dukes]

Oh I forgot.



Buy my book.

[mhgaffney]

I can tell none of you clowns actually listened to the interview.

[W*GS]

Zarembka's book is merely a rehash of long-since proven-wrong troofer canards.

No wonder gaffney sucks the guy's dick.

[Bronco_Beerslug]

Check out this excellent interview with Professor Paul Zarembka.

http://informationclearinghouse.info/article23122.htm
Being a cheerleader for as many delusional idiots and nuts as you are must be a full time job eh?

[elsid13]

Being a cheerleader for as many delusional idiots and nuts as you are must be a full time job eh?

He needs to find the funds to buy those tinfoil hats some way.

[TDmvp]

I can tell none of you clowns actually listened to the interview.

We never do , hence why all of us wonder why you still post .
Once in awhile we just post something in response to watch you dance ...

http://helllllen.org/blllllog/img/ConanandAWK-vi.gif

Dance GAFF Dance !!!

[DenverBrit]

the hidden history of 9/11

Such as....... who are the mystery owners of the WTC?

Idiot!

[orangeatheist]

i'm a writer! Found an angle to make a buck in 2001 and have been milking it for a living ever since! It's called "historical fiction" where i take a historical event and then fictionalize details around it. But in the end, never forget: I'm a writer! Not a researcher, not a scientist, not an engineer...no, nothing like that. A writer.

qft

[mhgaffney]

I never said or wrote what orange atheist claims I did.

Nor did I think it.

He edited my post. Only a loser would do this.

Hey orange -- you are a liar.

Nuf said.

MHG

[mhgaffney]

Zarembka's book is merely a rehash of long-since proven-wrong troofer canards.

No wonder gaffney sucks the guy's dick.

This from the guy who claimed on this board that temperature and heat were two different things.

Any high school physics or chemistry student would see through this clown. And W*gs claims to be a scientist.

Yeah -- and my grand uncle was honest Abe.

[frerottenextelway]

This from the guy who claimed on this board that temperature and heat were two different things.


Wait... they are two different things.

[W*GS]

gaffney knows as much about thermodynamics as he does elementary physics and simple metallurgy.

In short, ZERO.

[TDmvp]

I never said or wrote what orange atheist claims I did.

Nor did I think it.

He edited my post. Only a loser would do this.

Hey orange -- you are a liar.

Nuf said.

MHG



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[DenverBrit]

I never said or wrote what orange atheist claims I did.

Nuf said.

MHG

Of course not, you're not that honest.

[SoCalBronco]

Originally Posted by mhgaffney
i'm a writer! Found an angle to make a buck in 2001 and have been milking it for a living ever since!

http://www.orangemane.com/BB/attachment.php?attachmentid=23552&stc=1&d=1235861071

(Props to W*GS for making this)

[Bronco_Beerslug]

This from the guy who claimed on this board that temperature and heat were two different things.
You ignorant, uneducated bonehead, they ARE "two different things".

[TDmvp]

This from the guy who claimed on this board that temperature and heat were two different things.

Any high school physics or chemistry student would see through this clown. And W*gs claims to be a scientist.







Real Facts Science lesson of the day ...


Knowing the difference between heat and temperature is important if one is to have a clear understanding of energy.


A Wrong Idea

Often the concepts of heat and temperature are thought to be the same, but they are not.

Perhaps the reason the two are usually and incorrectly thought to be the same is because as human beings on Earth everyday experience leads us to notice that when you heat something up, say like putting a pot of water on the stove, then the temperature of that something goes up. More heat, more temperature - they must be the same, right? Turns out, though, this is not true.


Temperature is a number that is related to the average kinetic energy of the molecules of a substance. If temperature is measured in Kelvin degrees, then this number is directly proportional to the average kinetic energy of the molecules.

Heat is a measurement of the total energy in a substance. That total energy is made up of not only of the kinetic energies of the molecules of the substance, but total energy is also made up of the potential energies of the molecules.



Heat is energy.

Heat is the total amount of energy possessed by the molecules in a piece of matter. This energy is both kinetic energy and potential energy.


http://id.mind.net/~zona/mstm/physics/mechanics/energy/heatAndTemperature/heatAndTemperature.html

Google kills BS truthers dead , hell MAYBE I should write a book about owning truthers ...

All it took was typing "difference in heat and temperature" , and presto ....
You would think someone as smart as you Gaff would grasp something as simple as a search engine but I guess not ... For $hits and giggles it would be a blast to go "fact" by "fact" in your book and just type them into google and see how many I could prove are BS just by using the net and not even researching anything ...



But Gaff it's just that easy to prove you are about as smart as a retarded monkey...


And might I add , anyone with a grasp of reality and the ability to use a computer and understand what they read would know you are a snake oil salesmen and general POS from a mile away ....



And after kickin some Gaff @$$ , I can rest well ...

:thanku::thanku::thanku:

[DenverBrit]

This from the guy who claimed on this board that temperature and heat were two different things.

Any high school physics or chemistry student would see through this clown. And W*gs claims to be a scientist.

Yeah -- and my grand uncle was honest Abe.

So, how is Abe doing these days??

It's become clear that you don't understand 'high school level' chemistry or physics, yet you claim to have reviewed and critiqued the NIST report.

Obviously you wouldn't understand it if you read it, let alone point out its errors...... so which Troofer's work did you plagiarize??

[orangeatheist]

gaffney knows as much about thermodynamics as he does elementary physics and simple metallurgy.

In short, ZERO.

He's a writer! He doesn't need to know diddly-squat about physics to write about it!

[Bronco Bob]

This from the guy who claimed on this board that temperature and heat were two different things.



Are you so ignorant of science that you do think temperature and heat are the same thing?
Do you also think that voltage and current are the same thing?

[mhgaffney]

The scientific temperature scale is the Kelvin scale, named after Lord Kelvin who formulated the laws of thermodynamics.

The temperature scale starts with absolute zero -- which is by definition signifies zero heat. So you see that temperature and heat are simply two words for the same phenomenon. Two different ways of talking about it. Temperature measures it quantitatively . The word "heat" describes it qualitatively.

But it is the same phenomenon.

W*gs and Bronco Bob -- both clowns -- claimed that just because thermite burns at 4500 F that this does NOT mean it could melt steel -- which has a melting point of 2800 F.

Wrong. It not only can -- can. It did.

You guys are simply in denial -- and are grasping at straws -- out of desperation. It's also why you attack me.

[W*GS]

W*gs and Bronco Bob -- both clowns -- claimed that just because thermite burns at 4500 F that this does NOT mean it could melt steel -- which has a melting point of 2800 F.

Wrong. It not only can -- can. It did.

Remember my sparkler analogy?

Take a sparkler, burning at 3000° F, and dip it into a cup of water, which boils (at sea level) at 212° F.

Will all the water boil away, gaffney? Why or why not?

[mhgaffney]

W*gs -- you are an idiot.

[DenverBrit]

The scientific temperature scale is the Kelvin scale, named after Lord Kelvin who formulated the laws of thermodynamics.

The temperature scale starts with absolute zero -- which is by definition signifies zero heat. So you see that temperature and heat are simply two words for the same phenomenon. Two different ways of talking about it. Temperature measures it quantitatively . The word "heat" describes it qualitatively.

But it is the same phenomenon.

W*gs and Bronco Bob -- both clowns -- claimed that just because thermite burns at 4500 F that this does NOT mean it could melt steel -- which has a melting point of 2800 F.

Wrong. It not only can -- can. It did.

You guys are simply in denial -- and are grasping at straws -- out of desperation. It's also why you attack me.

Admit it, Gaffney, you just like to pull stuff out of your a$$.

Here, this simple explanation should be understood by even you:

Heat is the total energy of molecular motion in a substance while temperature is a measure of the average energy of molecular motion in a substance.
Heat energy depends on the speed of the particles, the number of particles (the size or mass), and the type of particles in an object. Temperature does not depend on the size or type of object.
For example, the temperature of a small cup of water might be the same as the temperature of a large tub of water, but the tub of water has more heat because it has more water and thus more total thermal energy.

Go it??

[Odysseus]

This thread is like a train wreck. I can't look away.

[mhgaffney]

The idea that thermite cannot cut steel beams is garbage.

The fact is uncontroversial. Thermite charges are not used as often as CDX -- but it is used and is more than capable of cutting steel beams.

Check around and you'll find it's true.

The heart versus temperature issue is bogus.

[Bronco_Beerslug]

The heart versus temperature issue is bogus.The more you try and and repair your ignorant stupid claims and statements the worse it gets for you.

You are the laughing stock of this site, a clueless fool.

[DenverBrit]

The idea that thermite cannot cut steel beams is garbage.

The fact is uncontroversial. Thermite charges are not used as often as CDX -- but it is used and is more than capable of cutting steel beams.

Check around and you'll find it's true.

The heart versus temperature issue is bogus.

Bogus??

Oh I get it, anything that doesn't fit your agenda and proves you're a charlatan is bogus.

You're an idiot-savant.....sans savant.

[Rohirrim]

People need to stop being so harsh on Gaff. I'm afraid you'll chase him away. I find him very entertaining. ;D

[W*GS]

W*gs -- you are an idiot.

Nope. Do the experiment. According to you, all the water will boil away - in fact, if you dipped your sparkler into the ocean, the entire ocean would evaporate, since 3000° F is more than 212° F.

[ElwayMD]

http://wiki.ytmnd.com/images/1/18/Lose.jpg

This is for you Gaff...

PS.. STOP POSTING YOUR ****...NO ONE CARES!!!

[W*GS]

gaffney, here's some homework for you - get the help of the scientists/engineers who allegedly applaud your work.

Calculate how much thermite it would take to melt through one of the typical WTC steel beams. Merely pointing out that thermite burns at a higher temperature than steel is far from sufficient.

Once you have the above figure, then calculate the total thermite needed to cut enough columns to cause collapse. You have the data from NIST on the WTC structure; it's quite straightforward.

Once you get the above homework done, then we can go on.

[DenverBrit]

People need to stop being so harsh on Gaff. I'm afraid you'll chase him away. I find him very entertaining. ;D

Nothing will scare the leach away, certainly not facts or reality.

He's addicted to himself and the sound of his own fonts. ;D

[mhgaffney]

gaffney, here's some homework for you - get the help of the scientists/engineers who allegedly applaud your work.

Calculate how much thermite it would take to melt through one of the typical WTC steel beams. Merely pointing out that thermite burns at a higher temperature than steel is far from sufficient.

Once you have the above figure, then calculate the total thermite needed to cut enough columns to cause collapse. You have the data from NIST on the WTC structure; it's quite straightforward.

Once you get the above homework done, then we can go on.

This has ALREADY been done -- many months ago.

You are simply too clueless to know about it.

Check out the video 9/11: Blueprint for Truth available via Architects and Engineers for 9/11 Truth.

www.AE911Truth.org

[W*GS]

gaffney, do your own work. Since you've claimed to understand the NIST report, it should be cake.

Also, show your work. Provide the equations.

Don't be such a lazy ass.

[Bronco_Beerslug]

gaffney, do your own work. Since you've claimed to understand the NIST report, it should be cake.

Also, show your work. Provide the equations.

Don't be such a lazy ass.He never does his "own" work evidenced by his constant parroting of other internet idiots.

[mhgaffney]

He never does his "own" work evidenced by his constant parroting of other internet idiots.

Beerslugger,

You are a typical drive by shooter. Shoot first -- talk later.

Dude, you missed it. Two weeks ago I posted my own research on the demand capacity ratios for the WTC. The NIST's own numbers showing that the WTC core columns had a factor of safety of 2.1 -- and the perimeter columns a factor of safety of 5.7.

Numbers confirmed to me by the NIST scientific committee.

Which, of course, means there is no way a piddling fire that never exceeded 600 C weakened and caused a comprehensive symmetrical collapse of the WTC to street level. Didn't happen and the numbers prove it.

FYI the core columns were 7 inches thick at the base. Again -- NIST's own numbers

You could have cut half the core columns - and most of the perimeter columns -- and the WTC would still have survived.

Like I said -- you missed these posts. I suggest you show some humility -- and back up and read them.

MHG

[DenverBrit]

Beerslugger,

You are a typical drive by shooter. Shoot first -- talk later.

Dude, you missed it. Two weeks ago I posted my own research on the demand capacity ratios for the WTC. The NIST's own numbers showing that the WTC core columns had a factor of safety of 2.1 -- and the perimeter columns a factor of safety of 5.7.

Numbers confirmed to me by the NIST scientific committee.

Which, of course, means there is no way a piddling fire that never exceeded 600 C weakened and caused a comprehensive symmetrical collapse of the WTC to street level. Didn't happen and the numbers prove it.

FYI the core columns were 7 inches thick at the base. Again -- NIST's own numbers

You could have cut half the core columns - and most of the perimeter columns -- and the WTC would still have survived.

Like I said -- you missed these posts. I suggest you show some humility -- and back up and read them.

MHG

LOLLOL Hilarious!ROFL!ROFL!ROFL! Gaffney!!! Projecting again!!

[W*GS]

So, gaffney, how's the homework coming?

Got the (minimum) total amount of thermite needed yet?

Where's your work?

[watermock]

Which, of course, means there is no way a piddling fire that never exceeded 600 C weakened and caused a comprehensive symmetrical collapse of the WTC to street level. Didn't happen and the numbers prove it.
.

Espeially WTC 7.

But that was where the SEC and Ennron papers were.

Frankly, it goes beyond suspcion.

There are so many anomalies on 9/11, frankly, I'm dissapointed there wasn't an impartial investigtion.

[Bronco_Beerslug]

Which, of course, means there is no way a piddling fire that never exceeded 600 C weakened and caused a comprehensive symmetrical collapse of the WTC to street level. Didn't happen and the numbers prove it.
Your knowledge of basic physics, chemistry and metallurgy is non-existent based on your own posts and the people you keep parroting, just like the one above.

I've already educated you on this many times but you refuse to listen and learn. Carbon steel melts at approx. 1250C. It also loses approx. half of it's strength at around 600C.

[mhgaffney]

Your knowledge of basic physics, chemistry and metallurgy is non-existent based on your own posts and the people you keep parroting, just like the one above.

I've already educated you on this many times but you refuse to listen and learn. Carbon steel melts at approx. 1250C. It also loses approx. half of it's strength at around 600C.

You are an arrogant bastard.

I stated the correct melting point of steel at 2800 Fahrenheit. Same difference as the Centigrade scale you cited.

Yeah steel may lose half its strength at 600 C -- but NIST found that none of its steel samples had been exposed to temperatures higher than 600 C.

In fact, according to NIST, only three steel samples out of 170 had been exposed to temperatures over 250 C (450 F). I repeat: only three samples higher than 450 F.

NIST recovered two core columns from the impact zone of WTC 2. From those samples it found no evidence of any slumping, sagging, bowing, or any other deformation that would be expected from failure die to prolonged exposure to high heat. I repeat: zero evidence.

You cannot derive a global collapse from these findings. NIST got there by tweaking its computer model again and again. Nor did NIST scientists ever reveal how they modified the inputs. A classic case of retro analysis. Keep tweaking the model until you get the required outcome.

But as I showed in my critique of the NISt report -- NIST's own numbers do not support its conclusions.

MHG

[mhgaffney]

Even if ALL of the steel columns in the WTC lost half their strength due to fire -- the WTC would not have collapsed.

This is the meaning of the demand capacity ratios -- another way of talking about factor of safety. No doubt, this is why NIST buried those numbers deep in the report. I only found this data by contacting NIST and asking them about it.

I already gave the link two or more weeks ago.

[mhgaffney]

And of course -- based on the fact that the fires in WTC 1 were generally waning in the period just before the collapse -- this means that the steel columns in WTC 1 were regaining strength when the building fell -- not losing strength.

Steel that has lost strength due to high heat will regain this strength again -- if the temperatures fall.

Therefor, the global collapse of WTC 1 is not explainable in terms of fire.

[Rohirrim]

Hey, Gaff? Who's you're favorite poet? I'm guessing it's Pablo Neruda.

[mhgaffney]

Yes Neruda -- but also WB Yeats.

[Rohirrim]

Yes. Yeats is one the all time greats.

[Bronco_Beerslug]

You are an arrogant bastard.

LOL

My "arrogance" comes from decades of working along side structural engineers erecting super structures. Yours is solely the result of ignorance, lack of education and internal makeup (100% fool).

---------------------------------------------------------------------
THE DESIGN (http://www.tms.org/pubs/journals/JOM/0112/Eagar/Eagar-0112.html)

The towers were designed and built in the mid-1960s through the early 1970s. They represented a new approach to skyscrapers in that they were to be very lightweight and involved modular construction methods in order to accelerate the schedule and to reduce the costs.

To a structural engineer, a skyscraper is modeled as a large cantilever vertical column. Each tower was 64 m square, standing 411 m above street level and 21 m below grade. This produces a height-to-width ratio of 6.8. The total weight of the structure was roughly 500,000 t, but wind load, rather than the gravity load, dominated the design. The building is a huge sail that must resist a 225 km/h hurricane. It was designed to resist a wind load of 2 kPa—a total of lateral load of 5,000 t.

In order to make each tower capable of withstanding this wind load, the architects selected a lightweight “perimeter tube” design consisting of 244 exterior columns of 36 cm square steel box section on 100 cm centers (see Figure 3). This permitted windows more than one-half meter wide. Inside this outer tube there was a 27 m × 40 m core, which was designed to support the weight of the tower. It also housed the elevators, the stairwells, and the mechanical risers and utilities. Web joists 80 cm tall connected the core to the perimeter at each story. Concrete slabs were poured over these joists to form the floors. In essence, the building is an egg-crate construction that is about 95 percent air, explaining why the rubble after the collapse was only a few stories high.

The egg-crate construction made a redundant structure (i.e., if one or two columns were lost, the loads would shift into adjacent columns and the building would remain standing). Prior to the World Trade Center with its lightweight perimeter tube design, most tall buildings contained huge columns on 5 m centers and contained massive amounts of masonry carrying some of the structural load. The WTC was primarily a lightweight steel structure; however, its 244 perimeter columns made it “one of the most redundant and one of the most resilient” skyscrapers.1
THE AIRLINE IMPACT

The early news reports noted how well the towers withstood the initial impact of the aircraft; however, when one recognizes that the buildings had more than 1,000 times the mass of the aircraft and had been designed to resist steady wind loads of 30 times the weight of the aircraft, this ability to withstand the initial impact is hardly surprising. Furthermore, since there was no significant wind on September 11, the outer perimeter columns were only stressed before the impact to around 1/3 of their 200 MPa design allowable.

The only individual metal component of the aircraft that is comparable in strength to the box perimeter columns of the WTC is the keel beam at the bottom of the aircraft fuselage. While the aircraft impact undoubtedly destroyed several columns in the WTC perimeter wall, the number of columns lost on the initial impact was not large and the loads were shifted to remaining columns in this highly redundant structure. Of equal or even greater significance during this initial impact was the explosion when 90,000 L gallons of jet fuel, comprising nearly 1/3 of the aircraft’s weight, ignited. The ensuing fire was clearly the principal cause of the collapse (Figure 4).

THE FIRE

The fire is the most misunderstood part of the WTC collapse. Even today, the media report (and many scientists believe) that the steel melted. It is argued that the jet fuel burns very hot, especially with so much fuel present. This is not true.

Part of the problem is that people (including engineers) often confuse temperature and heat. While they are related, they are not the same. Thermodynamically, the heat contained in a material is related to the temperature through the heat capacity and the density (or mass). Temperature is defined as an intensive property, meaning that it does not vary with the quantity of material, while the heat is an extensive property, which does vary with the amount of material. One way to distinguish the two is to note that if a second log is added to the fireplace, the temperature does not double; it stays roughly the same, but the size of the fire or the length of time the fire burns, or a combination of the two, doubles. Thus, the fact that there were 90,000 L of jet fuel on a few floors of the WTC does not mean that this was an unusually hot fire. The temperature of the fire at the WTC was not unusual, and it was most definitely not capable of melting steel.

In combustion science, there are three basic types of flames, namely, a jet burner, a pre-mixed flame, and a diffuse flame. A jet burner generally involves mixing the fuel and the oxidant in nearly stoichiometric proportions and igniting the mixture in a constant-volume chamber. Since the combustion products cannot expand in the constant-volume chamber, they exit the chamber as a very high velocity, fully combusted, jet. This is what occurs in a jet engine, and this is the flame type that generates the most intense heat.

In a pre-mixed flame, the same nearly stoichiometric mixture is ignited as it exits a nozzle, under constant pressure conditions. It does not attain the flame velocities of a jet burner. An oxyacetylene torch or a Bunsen burner is a pre-mixed flame.

In a diffuse flame, the fuel and the oxidant are not mixed before ignition, but flow together in an uncontrolled manner and combust when the fuel/oxidant ratios reach values within the flammable range. A fireplace flame is a diffuse flame burning in air, as was the WTC fire.

Diffuse flames generate the lowest heat intensities of the three flame types.

If the fuel and the oxidant start at ambient temperature, a maximum flame temperature can be defined. For carbon burning in pure oxygen, the maximum is 3,200°C; for hydrogen it is 2,750°C. Thus, for virtually any hydrocarbons, the maximum flame temperature, starting at ambient temperature and using pure oxygen, is approximately 3,000°C.

This maximum flame temperature is reduced by two-thirds if air is used rather than pure oxygen. The reason is that every molecule of oxygen releases the heat of formation of a molecule of carbon monoxide and a molecule of water. If pure oxygen is used, this heat only needs to heat two molecules (carbon monoxide and water), while with air, these two molecules must be heated plus four molecules of nitrogen. Thus, burning hydrocarbons in air produces only one-third the temperature increase as burning in pure oxygen because three times as many molecules must be heated when air is used. The maximum flame temperature increase for burning hydrocarbons (jet fuel) in air is, thus, about 1,000°C—hardly sufficient to melt steel at 1,500°C.

But it is very difficult to reach this maximum temperature with a diffuse flame. There is nothing to ensure that the fuel and air in a diffuse flame are mixed in the best ratio. Typically, diffuse flames are fuel rich, meaning that the excess fuel molecules, which are unburned, must also be heated. It is known that most diffuse fires are fuel rich because blowing on a campfire or using a blacksmith’s bellows increases the rate of combustion by adding more oxygen. This fuel-rich diffuse flame can drop the temperature by up to a factor of two again. This is why the temperatures in a residential fire are usually in the 500°C to 650°C range.2,3 It is known that the WTC fire was a fuel-rich, diffuse flame as evidenced by the copious black smoke. Soot is generated by incompletely burned fuel; hence, the WTC fire was fuel rich—hardly surprising with 90,000 L of jet fuel available. Factors such as flame volume and quantity of soot decrease the radiative heat loss in the fire, moving the temperature closer to the maximum of 1,000°C. However, it is highly unlikely that the steel at the WTC experienced temperatures above the 750–800°C range. All reports that the steel melted at 1,500°C are using imprecise terminology at best.

Some reports suggest that the aluminum from the aircraft ignited, creating very high temperatures. While it is possible to ignite aluminum under special conditions, such conditions are not commonly attained in a hydrocarbon-based diffuse flame. In addition, the flame would be white hot, like a giant sparkler. There was no evidence of such aluminum ignition, which would have been visible even through the dense soot.

It is known that structural steel begins to soften around 425°C and loses about half of its strength at 650°C.4 This is why steel is stress relieved in this temperature range. But even a 50% loss of strength is still insufficient, by itself, to explain the WTC collapse. It was noted above that the wind load controlled the design allowables. The WTC, on this low-wind day, was likely not stressed more than a third of the design allowable, which is roughly one-fifth of the yield strength of the steel. Even with its strength halved, the steel could still support two to three times the stresses imposed by a 650°C fire.

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.

THE COLLAPSE

Nearly every large building has a redundant design that allows for loss of one primary structural member, such as a column. However, when multiple members fail, the shifting loads eventually overstress the adjacent members and the collapse occurs like a row of dominoes falling down.

The perimeter tube design of the WTC was highly redundant. It survived the loss of several exterior columns due to aircraft impact, but the ensuing fire led to other steel failures. Many structural engineers believe that the weak points—the limiting factors on design allowables—were the angle clips that held the floor joists between the columns on the perimeter wall and the core structure (see Figure 5). With a 700 Pa floor design allowable, each floor should have been able to support approximately 1,300 t beyond its own weight. The total weight of each tower was about 500,000 t.

As the joists on one or two of the most heavily burned floors gave way and the outer box columns began to bow outward, the floors above them also fell. The floor below (with its 1,300 t design capacity) could not support the roughly 45,000 t of ten floors (or more) above crashing down on these angle clips. This started the domino effect that caused the buildings to collapse within ten seconds, hitting bottom with an estimated speed of 200 km per hour. If it had been free fall, with no restraint, the collapse would have only taken eight seconds and would have impacted at 300 km/h.1 It has been suggested that it was fortunate that the WTC did not tip over onto other buildings surrounding the area. There are several points that should be made. First, the building is not solid; it is 95 percent air and, hence, can implode onto itself. Second, there is no lateral load, even the impact of a speeding aircraft, which is sufficient to move the center of gravity one hundred feet to the side such that it is not within the base footprint of the structure. Third, given the near free-fall collapse, there was insufficient time for portions to attain significant lateral velocity. To summarize all of these points, a 500,000 t structure has too much inertia to fall in any direction other than nearly straight down.

WAS THE WTC DEFECTIVELY DESIGNED?

The World Trade Center was not defectively designed. No designer of the WTC anticipated, nor should have anticipated, a 90,000 L Molotov cocktail on one of the building floors. Skyscrapers are designed to support themselves for three hours in a fire even if the sprinkler system fails to operate. This time should be long enough to evacuate the occupants. The WTC towers lasted for one to two hours—less than the design life, but only because the fire fuel load was so large. No normal office fires would fill 4,000 square meters of floor space in the seconds in which the WTC fire developed. Usually, the fire would take up to an hour to spread so uniformly across the width and breadth of the building. This was a very large and rapidly progressing fire (very high heat but not unusually high temperature). Further information about the design of the WTC can be found on the World Wide Web.5–8.

References

1. Presentation on WTC Collapse, Civil Engineering Department, MIT, Cambridge, MA (October 3, 2001).
2. D. Drysdale, An Introduction to Fire Dynamics (New York: Wiley Interscience, 1985), pp. 134–140.
3. A.E. Cote, ed., Fire Protection Handbook 17th Edition (Quincy, MA: National Fire Protection Association, 1992), pp. 10–67.
4. A.E. Cote, ed., Fire Protection Handbook 17th Edition (Quincy, MA: National Fire Protection Association, 1992), pp. 6-62 to 6-70.
5. Steven Ashley, “When the Twin Towers Fell,” Scientific American Online (October 9, 2001); www.sciam.com/explorations/2001/100901wtc/
6. Zdenek P. Bazant and Yong Zhou, “Why Did the World Trade Center Collapse?—Simple Analysis,” J. Engineering Mechanics ASCE, (September 28, 2001), also www.tam.uiuc.edu/news/200109wtc/
7. Timothy Wilkinson, “World Trade Centre–New York—Some Engineering Aspects” (October 25, 2001), Univ. Sydney, Department of Civil Engineering; www.civil.usyd.edu.au/wtc.htm.
8. G. Charles Clifton, “Collapse of the World Trade Centers,” CAD Headlines, tenlinks.com (October 8, 2001); www.tenlinks.com/NEWS/special/wtc/clifton/p1.htm.

Thomas W. Eagar, the Thomas Lord Professor of Materials Engineering and Engineering Systems, and Christopher Musso, graduate research student, are at the Massachusetts Institute of Technology.

[mhgaffney]

LOL

My "arrogance" comes from decades of working along side structural engineers erecting super structures. Yours is solely the result of ignorance, lack of education and internal makeup (100% fool).

---------------------------------------------------------------------
THE DESIGN (http://www.tms.org/pubs/journals/JOM/0112/Eagar/Eagar-0112.html)

The towers were designed and built in the mid-1960s through the early 1970s. They represented a new approach to skyscrapers in that they were to be very lightweight and involved modular construction methods in order to accelerate the schedule and to reduce the costs.

To a structural engineer, a skyscraper is modeled as a large cantilever vertical column. Each tower was 64 m square, standing 411 m above street level and 21 m below grade. This produces a height-to-width ratio of 6.8. The total weight of the structure was roughly 500,000 t, but wind load, rather than the gravity load, dominated the design. The building is a huge sail that must resist a 225 km/h hurricane. It was designed to resist a wind load of 2 kPa—a total of lateral load of 5,000 t.

In order to make each tower capable of withstanding this wind load, the architects selected a lightweight “perimeter tube” design consisting of 244 exterior columns of 36 cm square steel box section on 100 cm centers (see Figure 3). This permitted windows more than one-half meter wide. Inside this outer tube there was a 27 m × 40 m core, which was designed to support the weight of the tower. It also housed the elevators, the stairwells, and the mechanical risers and utilities. Web joists 80 cm tall connected the core to the perimeter at each story. Concrete slabs were poured over these joists to form the floors. In essence, the building is an egg-crate construction that is about 95 percent air, explaining why the rubble after the collapse was only a few stories high.

The egg-crate construction made a redundant structure (i.e., if one or two columns were lost, the loads would shift into adjacent columns and the building would remain standing). Prior to the World Trade Center with its lightweight perimeter tube design, most tall buildings contained huge columns on 5 m centers and contained massive amounts of masonry carrying some of the structural load. The WTC was primarily a lightweight steel structure; however, its 244 perimeter columns made it “one of the most redundant and one of the most resilient” skyscrapers.1
THE AIRLINE IMPACT

The early news reports noted how well the towers withstood the initial impact of the aircraft; however, when one recognizes that the buildings had more than 1,000 times the mass of the aircraft and had been designed to resist steady wind loads of 30 times the weight of the aircraft, this ability to withstand the initial impact is hardly surprising. Furthermore, since there was no significant wind on September 11, the outer perimeter columns were only stressed before the impact to around 1/3 of their 200 MPa design allowable.

The only individual metal component of the aircraft that is comparable in strength to the box perimeter columns of the WTC is the keel beam at the bottom of the aircraft fuselage. While the aircraft impact undoubtedly destroyed several columns in the WTC perimeter wall, the number of columns lost on the initial impact was not large and the loads were shifted to remaining columns in this highly redundant structure. Of equal or even greater significance during this initial impact was the explosion when 90,000 L gallons of jet fuel, comprising nearly 1/3 of the aircraft’s weight, ignited. The ensuing fire was clearly the principal cause of the collapse (Figure 4).

THE FIRE

The fire is the most misunderstood part of the WTC collapse. Even today, the media report (and many scientists believe) that the steel melted. It is argued that the jet fuel burns very hot, especially with so much fuel present. This is not true.

Part of the problem is that people (including engineers) often confuse temperature and heat. While they are related, they are not the same. Thermodynamically, the heat contained in a material is related to the temperature through the heat capacity and the density (or mass). Temperature is defined as an intensive property, meaning that it does not vary with the quantity of material, while the heat is an extensive property, which does vary with the amount of material. One way to distinguish the two is to note that if a second log is added to the fireplace, the temperature does not double; it stays roughly the same, but the size of the fire or the length of time the fire burns, or a combination of the two, doubles. Thus, the fact that there were 90,000 L of jet fuel on a few floors of the WTC does not mean that this was an unusually hot fire. The temperature of the fire at the WTC was not unusual, and it was most definitely not capable of melting steel.

In combustion science, there are three basic types of flames, namely, a jet burner, a pre-mixed flame, and a diffuse flame. A jet burner generally involves mixing the fuel and the oxidant in nearly stoichiometric proportions and igniting the mixture in a constant-volume chamber. Since the combustion products cannot expand in the constant-volume chamber, they exit the chamber as a very high velocity, fully combusted, jet. This is what occurs in a jet engine, and this is the flame type that generates the most intense heat.

In a pre-mixed flame, the same nearly stoichiometric mixture is ignited as it exits a nozzle, under constant pressure conditions. It does not attain the flame velocities of a jet burner. An oxyacetylene torch or a Bunsen burner is a pre-mixed flame.

In a diffuse flame, the fuel and the oxidant are not mixed before ignition, but flow together in an uncontrolled manner and combust when the fuel/oxidant ratios reach values within the flammable range. A fireplace flame is a diffuse flame burning in air, as was the WTC fire.

Diffuse flames generate the lowest heat intensities of the three flame types.

If the fuel and the oxidant start at ambient temperature, a maximum flame temperature can be defined. For carbon burning in pure oxygen, the maximum is 3,200°C; for hydrogen it is 2,750°C. Thus, for virtually any hydrocarbons, the maximum flame temperature, starting at ambient temperature and using pure oxygen, is approximately 3,000°C.

This maximum flame temperature is reduced by two-thirds if air is used rather than pure oxygen. The reason is that every molecule of oxygen releases the heat of formation of a molecule of carbon monoxide and a molecule of water. If pure oxygen is used, this heat only needs to heat two molecules (carbon monoxide and water), while with air, these two molecules must be heated plus four molecules of nitrogen. Thus, burning hydrocarbons in air produces only one-third the temperature increase as burning in pure oxygen because three times as many molecules must be heated when air is used. The maximum flame temperature increase for burning hydrocarbons (jet fuel) in air is, thus, about 1,000°C—hardly sufficient to melt steel at 1,500°C.

But it is very difficult to reach this maximum temperature with a diffuse flame. There is nothing to ensure that the fuel and air in a diffuse flame are mixed in the best ratio. Typically, diffuse flames are fuel rich, meaning that the excess fuel molecules, which are unburned, must also be heated. It is known that most diffuse fires are fuel rich because blowing on a campfire or using a blacksmith’s bellows increases the rate of combustion by adding more oxygen. This fuel-rich diffuse flame can drop the temperature by up to a factor of two again. This is why the temperatures in a residential fire are usually in the 500°C to 650°C range.2,3 It is known that the WTC fire was a fuel-rich, diffuse flame as evidenced by the copious black smoke. Soot is generated by incompletely burned fuel; hence, the WTC fire was fuel rich—hardly surprising with 90,000 L of jet fuel available. Factors such as flame volume and quantity of soot decrease the radiative heat loss in the fire, moving the temperature closer to the maximum of 1,000°C. However, it is highly unlikely that the steel at the WTC experienced temperatures above the 750–800°C range. All reports that the steel melted at 1,500°C are using imprecise terminology at best.

Some reports suggest that the aluminum from the aircraft ignited, creating very high temperatures. While it is possible to ignite aluminum under special conditions, such conditions are not commonly attained in a hydrocarbon-based diffuse flame. In addition, the flame would be white hot, like a giant sparkler. There was no evidence of such aluminum ignition, which would have been visible even through the dense soot.

It is known that structural steel begins to soften around 425°C and loses about half of its strength at 650°C.4 This is why steel is stress relieved in this temperature range. But even a 50% loss of strength is still insufficient, by itself, to explain the WTC collapse. It was noted above that the wind load controlled the design allowables. The WTC, on this low-wind day, was likely not stressed more than a third of the design allowable, which is roughly one-fifth of the yield strength of the steel. Even with its strength halved, the steel could still support two to three times the stresses imposed by a 650°C fire.

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.

THE COLLAPSE

Nearly every large building has a redundant design that allows for loss of one primary structural member, such as a column. However, when multiple members fail, the shifting loads eventually overstress the adjacent members and the collapse occurs like a row of dominoes falling down.

The perimeter tube design of the WTC was highly redundant. It survived the loss of several exterior columns due to aircraft impact, but the ensuing fire led to other steel failures. Many structural engineers believe that the weak points—the limiting factors on design allowables—were the angle clips that held the floor joists between the columns on the perimeter wall and the core structure (see Figure 5). With a 700 Pa floor design allowable, each floor should have been able to support approximately 1,300 t beyond its own weight. The total weight of each tower was about 500,000 t.

As the joists on one or two of the most heavily burned floors gave way and the outer box columns began to bow outward, the floors above them also fell. The floor below (with its 1,300 t design capacity) could not support the roughly 45,000 t of ten floors (or more) above crashing down on these angle clips. This started the domino effect that caused the buildings to collapse within ten seconds, hitting bottom with an estimated speed of 200 km per hour. If it had been free fall, with no restraint, the collapse would have only taken eight seconds and would have impacted at 300 km/h.1 It has been suggested that it was fortunate that the WTC did not tip over onto other buildings surrounding the area. There are several points that should be made. First, the building is not solid; it is 95 percent air and, hence, can implode onto itself. Second, there is no lateral load, even the impact of a speeding aircraft, which is sufficient to move the center of gravity one hundred feet to the side such that it is not within the base footprint of the structure. Third, given the near free-fall collapse, there was insufficient time for portions to attain significant lateral velocity. To summarize all of these points, a 500,000 t structure has too much inertia to fall in any direction other than nearly straight down.

WAS THE WTC DEFECTIVELY DESIGNED?

The World Trade Center was not defectively designed. No designer of the WTC anticipated, nor should have anticipated, a 90,000 L Molotov cocktail on one of the building floors. Skyscrapers are designed to support themselves for three hours in a fire even if the sprinkler system fails to operate. This time should be long enough to evacuate the occupants. The WTC towers lasted for one to two hours—less than the design life, but only because the fire fuel load was so large. No normal office fires would fill 4,000 square meters of floor space in the seconds in which the WTC fire developed. Usually, the fire would take up to an hour to spread so uniformly across the width and breadth of the building. This was a very large and rapidly progressing fire (very high heat but not unusually high temperature). Further information about the design of the WTC can be found on the World Wide Web.5–8.

References

1. Presentation on WTC Collapse, Civil Engineering Department, MIT, Cambridge, MA (October 3, 2001).
2. D. Drysdale, An Introduction to Fire Dynamics (New York: Wiley Interscience, 1985), pp. 134–140.
3. A.E. Cote, ed., Fire Protection Handbook 17th Edition (Quincy, MA: National Fire Protection Association, 1992), pp. 10–67.
4. A.E. Cote, ed., Fire Protection Handbook 17th Edition (Quincy, MA: National Fire Protection Association, 1992), pp. 6-62 to 6-70.
5. Steven Ashley, “When the Twin Towers Fell,” Scientific American Online (October 9, 2001); www.sciam.com/explorations/2001/100901wtc/
6. Zdenek P. Bazant and Yong Zhou, “Why Did the World Trade Center Collapse?—Simple Analysis,” J. Engineering Mechanics ASCE, (September 28, 2001), also www.tam.uiuc.edu/news/200109wtc/
7. Timothy Wilkinson, “World Trade Centre–New York—Some Engineering Aspects” (October 25, 2001), Univ. Sydney, Department of Civil Engineering; www.civil.usyd.edu.au/wtc.htm.
8. G. Charles Clifton, “Collapse of the World Trade Centers,” CAD Headlines, tenlinks.com (October 8, 2001); www.tenlinks.com/NEWS/special/wtc/clifton/p1.htm.

Thomas W. Eagar, the Thomas Lord Professor of Materials Engineering and Engineering Systems, and Christopher Musso, graduate research student, are at the Massachusetts Institute of Technology.


Yes, we know about Eagar's pancake collapse model -- which he proposed in the period immediately following 9/11.

The problem for you, Beerslugger, is that NIST rejected Eagar's pancake model in its final report released in September 2005. The failure of some angle clips on a few floors did NOT cause the collapse. NIST found that the floor attachments to the core and perimeter columns were much more substantial than what Eagar had assumed. For example, the floor trusses were not only bolted but also welded -- hence were MUCH stronger than what Eagar claims.

Since NIST itself rejected the theory you support -- there is no longer any compelling need to discuss Eagar's pancake model.

I suggest you actually read the NIST report before you open your BIG mouth.

MHG

[W*GS]

So, gaffney, how's the homework coming?

Got the (minimum) total amount of thermite needed yet?

Where's your work?

[Rohirrim]

Yes, we know about Eagar's pancake collapse model -- which he proposed in the period immediately following 9/11.

The problem for you, Beerslugger, is that NIST rejected Eagar's pancake model in its final report released in September 2005. The failure of some angle clips on a few floors did NOT cause the collapse. NIST found that the floor attachments to the core and perimeter columns were much more substantial than what Eagar had assumed. For example, the floor trusses were not only bolted but also welded -- hence were MUCH stronger than what Eagar claims.

Since NIST itself rejected the theory you support -- there is no longer any compelling need to discuss Eagar's pancake model.

I suggest you actually read the NIST report before you open your BIG mouth.

MHG

Given the fact that the towers did in fact, "pancake," I would say the "pancake theory" is a given. Maybe Eagar's theory regarding how that took place needs modification, but the fact that the buildings did pancake cannot be disputed. He is also right that a structure with such enormous inertia could not possibly do anything else but come straight down, unless maybe King Kong was pushing it over. In any theory about why the buildings did collapse I would be sure to include the two planes full of fuel crashing into them. I still believe that had something to do with it. ;D

[Bronco_Beerslug]

Yes, we know about Eagar's pancake collapse model -- which he proposed in the period immediately following 9/11.

The problem for you, Beerslugger, is that NIST rejected Eagar's pancake model in its final report released in September 2005. The failure of some angle clips on a few floors did NOT cause the collapse. NIST found that the floor attachments to the core and perimeter columns were much more substantial than what Eagar had assumed. For example, the floor trusses were not only bolted but also welded -- hence were MUCH stronger than what Eagar claims.

Since NIST itself rejected the theory you support -- there is no longer any compelling need to discuss Eagar's pancake model.

I suggest you actually read the NIST report before you open your BIG mouth.

MHGAnother problem you have, reading comprehension. I already pointed this out in previous threads (about the floor truss connectors in the NIST report). It didn't mater that that truss seats were welded as well as bolted (most simply sheared). The Collapse was due to multiple causes, every structural engineer understands this.

--------------------------------------------------------------
From NIST report....
3.5.6 Summary
From the observations made on recovered panels concerning the floor truss connectors, the most significant data was observed when the panels were separated by floor elevation. Of the 28 floor truss connectors at or below the impact floors for WTC 1, 93 percent were either missing or bent downward; only 37 percent of the 38 floor truss connectors above the impact floors. Similar results were found for WTC 2, where 88 percent of the floor truss connectors below the impact floors were bent down or
missing, while only 55 percent of the floor truss connectors above the this region experienced analogous damage characteristics. This occurrence was most likely a result of the overloading of the lower floors (“pancaking” mechanism) during collapse of the building. When the seats were observed missing, it was typically a result of fracture near a welded joint associated with the standoff plates. Inspection of the welded failures associated with the floor truss connectors showed that failure typically occurred in the
location with the lowest cross-sectional area. However, there was no evidence throughout this analysis toindicate that fracture associated with the welds evaluated was related to: 1) inadequate joining materials
(weld strength and ductility appeared appropriate for the application), 2) inappropriate welding procedures (welds were typically oversized with no visible flaws), or 3) poor performance of the welded joint (fracture was associated with extreme loading event, i.e., overloading of the floors upon collapse).

---------------------------------------------------------------
Figure B-11 Shear failure of floor truss connections from column/spandrel plate. (http://911research.wtc7.net/mirrors/guardian2/wtc/WTC_apndxB.htm)

Many of the bearing seat brackets and the damper angle connections on the column/spandrel beam plate were completely sheared off. Only the weld segments remained on face of the column/spandrel beam plate (Figure B-11). This mode of failure appears to be due to excessive vertical overloads on the floor system. This is in contrast with the failure mode exhibited in Figure B-9 where the bearing seat bracket has pulled away from the column/spandrel plate, after fracture of the top chord gusset plate.

B.4.4 WTC 5 Column-Tree Shear Connections

Chapter 4, Section 4.3.2, noted that limited structural collapse had occurred in WTC 5 as a result of failure at the shear connections between the infill beams and the column tree beam stub cantilevers. It is visually apparent from Figures 4-18, 4-19, 4-20, and 4-21 that the fire-weakened structural members formed diagonal tension field failure mechanism in the cantilever beam webs and plastic hinge moments in the cantilever beam near the column face. The following analysis examines the capacity of the cantilever beams and the shear connections between the cantilever and the infill beams.

The magnitude of the shear force acting at the end of the cantilever section can be estimated from the plastic moment capacity and the plastic shear yield capacity (AISC 2001). The plastic moment capacity of a W24x61 steel section is


and the shear yield capacity is


where Fy = 40 ksi is the approximate yield strength of the A36 steel sections at room temperature, Zx is the plastic section modulus, d is the beam depth, and tw is the web thickness.

The vertical shear capacity of the bolted double shear splice connecting the W18x50 section to the W24x61 cantilever can be estimated for the three-bolt connection from the bearing strength relationship given in Section B.4.2. This gives


where db = 3/4 inch is the bolt diameter, tw = 3/8 inch is the web thickness for a W18x50, and Fu = 60 ksi is the approximate tensile strength of A36 steel.

Appendix A indicates the yield strength is 0.9 Fy at 200 degrees Centigrade (392 degrees Fahrenheit) and the yield strength is 0.5 Fy at 550 degrees Centigrade (1,022 degrees Fahrenheit). The large plastic deformation observed in the cantilever beam segments suggests that a significant loss of strength developed due to the fire. The fire temperatures reached in WTC 5 are not known, but if it is assumed for the purposes of this analysis that 550 degrees Centigrade (1,022 degrees Fahrenheit) was reached, this analysis estimates the cantilever plastic moment capacity as


This corresponds to a shear force of about 126 kips at room temperature acting at the end of the 4-foot cantilever, which would be reduced to 63 kips at 550 degrees Centigrade (1,022 degrees Fahrenheit). The limiting shear yield strength of the cantilever is


assuming the full web is effective. Hence, the three-bolt capacity is


The double shear capacity of the three 3/4-inch high-strength bolts is


where Fub = 120 ksi is the bolt tensile strength at room temperature (see Section B.3.3) and Ab = 0.4418 square inch is the bolt area. At 550 degrees Centigrade (1,022 degrees Fahrenheit), the bolt tensile strength is approximately (0.51)(1.18)Fub which is about 71 ksi.

This verifies that the bolted shear connections have sufficient capacity to develop the reduced plastic moment capacity of the fire-weakened steel beam cantilever and sustain large vertical deformation.

The failures all appear to be a result of the large tensile force that developed in the structural system during the fire and/or as the structure cooled. As demonstrated in Section B.4.2, the tensile capacity of the bolted shear splice in the beam web can be estimated for a bolt as


with Le = 1.344 inches is the edge distance, t = 0.375 inch is the plate thickness in bearing, and Fu is the applicable tensile strength.


The photographs in Figure 4-22, in Chapter 4, indicate that the deformed structure subjected the bolted shear connection to a large tensile force. At 550 degrees Centigrade (1,022 degrees Fahrenheit), the ultimate resistance of the three bolts is about 45 kips. The capacity increases to about 90 kips at room temperature. Failure occurred between these bounds.

Tensile catenary action of this type of floor framing members and their connections has not been a design requirement or consideration for most buildings. For the analysis shown here, with assumed fire temperatures, increasing the end distance Le to 2.25 inches would increase the tensile capacity of the three bolts to about 76 kips at 550 degrees Centigrade (1,022 degrees Fahrenheit) and 152 kips at room temperature, because the resistance would increase to the limit in Equation B-20.

B.5 References

AISC. 2001. Manual of Steel Construction, LRFD. 3rd Edition. Chicago.

ASTM. 1999. ASTM E1820 Standard Test Method for Measurement of Fracture Toughness. Brockenbrough, R.L., and Johnston, B.G. 1968. USS Steel Design Manual. USS, Pittsburgh, PA. Fisher, J. W., Galambos, T. V., Kulak, G. L., and Ravindra, M. K. 1978. "Load and Resistance Factor Design Criteria for Connectors," Journal of Structural Division. ASCE, Vol. 104, No. ST9, September.

Kulak, G. L., Fisher, J. W., and Struik, J. H. A. 1987. Guide to Design Criteria for Bolted and Riveted Joints. 2nd Edition. Wiley, NY.

Lesik, D. F. and Kennedy, D. J. L. 1990. "Ultimate Strength of Fillet Welded Connections Loaded InPlane," Canadian Journal of Civil Engineering. Vol. 17, No. 1.

PATH-NYNJ. 1976. PATH-NYNJ Document 761101, The World Trade Center: A Building Project Like No Other. May.

Salmon, C. G., and Johnson, J. E. 1996. Steel Structures, Design and Behavior. 4th Edition. Harper Collins. Structural Steel Design. 1974. L. Tall, Ed. 2nd Edition. Ronald Press. USX. 1998. Making, Shaping, and Treating of Steel.

[mhgaffney]

Given the fact that the towers did in fact, "pancake," I would say the "pancake theory" is a given. Maybe Eagar's theory regarding how that took place needs modification, but the fact that the buildings did pancake cannot be disputed. He is also right that a structure with such enormous inertia could not possibly do anything else but come straight down, unless maybe King Kong was pushing it over. In any theory about why the buildings did collapse I would be sure to include the two planes full of fuel crashing into them. I still believe that had something to do with it. ;D

Pancake you would say --= but you would be wrong.

"Pancake" has a specific meaning. We have all seen photos of buildings that fell due to earthquakes. In these photos you can clearly see the concrete floors piled one on another. These buildings collapse like an accordion. This is a typical pancake type of collapse.

No such a thing happened to the WTC. If you studied the WTC rubble pile -- and I did -- you will know there were no such floors piled up at ground zero. In fact, the pile was almost exclusively steel and other kinds of metal. Very little concrete survived the collapse.

Most of the concrete -- and the WTC was largely made of concrete -- disintegrated in mid air -- long before it ever reached the ground.

We all saw the vast cloud of dust over Manhattan -- a cloud easily visible from space. Much of it was concrete dust.

Although few noticed at the time -- the cloud itself was another piece of evidence pointing to demolition. Because it took a lot of energy to transform all of that concrete -- reinforced concrete BTW -- to dust before our eyes.

So where did this energy come from?

I'll give you three guesses.

[mhgaffney]

Sorry but I have to cry "Bull****!"

Beerslugger just posted (above) a lengthy piece of the early article by Dr Thomas Eagar, with whom he apparently agreed. Why else post it?

I pointed out that NIST rejected Eagar's collapse model in its final report.

Now Beerslugger retreats from his post faster than the roadrunner.

You can't have it both ways.

Beerslugger lashes out reflexively -- like a knee jerk -- at anyone or anything that impinges on his comfort zone.

MHG

[DenverBrit]

Sorry but I have to cry "Bull****!"

Beerslugger just posted (above) a lengthy piece of the early article by Dr Thomas Eagar, with whom he apparently agreed. Why else post it?

I pointed out that NIST rejected Eagar's collapse model in its final report.

Now Beerslugger retreats from his post faster than the roadrunner.

You can't have it both ways.

Beerslugger lashes out reflexively -- like a knee jerk -- at anyone or anything that impinges on his comfort zone.

MHG

So the NIST report is only correct when you agree with it's findings??

How convenient and typical of a Troofer.

Get over yourself!!

[Rohirrim]

Here's an analysis by "real" scientists who specialize in demolition, structural vibration and seismology. http://www.protecservices.com/vibration.htm

NOTE: They had seismographic equipment operating in Manhattan when the planes hit and operating throughout the collapse. They also have film.


A CRITICAL ANALYSIS OF THE COLLAPSE OF WTC TOWERS 1, 2 & 7 FROM AN
EXPLOSIVES AND CONVENTIONAL DEMOLITION INDUSTRY VIEWPOINT

By Brent Blanchard
August 8, 2006
c-2006 www.implosionworld.com

==================

ASSERTION #1
“The towers’ collapse looked exactly like explosive demolitions.”
PROTEC COMMENT: No they didn’t. It’s the “where.”

When discussing similarities between the towers’ collapse and an explosive demolition,
many people overlook the single question most central to any objective investigation. It
is not “how” or “when” the buildings failed, but “where” they failed. That answer holds
the key to understanding almost everything that occurred at Ground Zero.

Since their inception in the late 1800s, blasting engineers have understood that building
implosions work best when the forces of gravity are maximized. This is why blasters
always concentrate their efforts on the lowest floors of a structure. While smaller
supplemental charges can be placed on upper floors to facilitate breakage and maximize
control as the structure collapses, every implosion ever performed has followed the
basic model of obliterating structural supports on the bottom few floors first, “to get the
structure moving.”

This was not the case with the collapse of Towers 1 and 2. Close examination of these
events from every video and photographic angle available does not indicate failure
originating from the lowest floors, rather clearly shows each building beginning to fail at
precisely the point where the respective planes struck. That is, no floors above or below
the impact points ever move until the structural elements within the impact zone begin to
collapse (WTC 7 collapsed differently, which we will cover later).

Furthermore, there are no independent failures present while the structures are
collapsing (we’re not talking dust plumes or debris, but actual structural failure). All
lower floors remained completely intact until they were consumed by the collapse from
above.

Because countless images confirm this assessment and none contradict it, we believe
this fact to be visually indisputable.

Therefore, for explosives to be considered as a primary or supplemental catalyst, one
would have to accept that either, a) dozens of charges were placed on those exact
impact floors in advance and survived the violent initial explosions and 1100+ degree
Fahrenheit fires, or b) while the fires were burning, charges were installed undetected
throughout the impact floors and wired together, ostensibly by people hiding in the
buildings with boxes of explosives. There is no third choice that could adequately
explain explosives causing failure at the exact impact points.

The chemical properties of explosives and their reaction to heat render scenario A
scientifically impossible and scenario B remarkably unlikely, as we know of no explosive
compound that could withstand such force and/or heat without detaching from the
columns or simply burning off prior to detonation.

There are other problems with both scenarios: Given the consistent weight distribution
around the outer perimeter of each structure, one would have needed access to a
prohibitively large quantity of load-bearing I-beam columns to allow “cutter charges” to
initiate failure. Those columns would have needed extensive preparation, also known as
“pre-burning”, to allow the explosives to perform their function. And in order to prepare
the columns you first had to be able to see the columns, which means at least partially
removing the outer-perimeter interior walls of all blast floors, including furniture,
plumbing and conduit lines, insulation, etc.

All of this would have been performed within the 55 minutes between plane impact and
collapse – working in an environment of unspeakable heat and destruction – or have
been performed completely undetected, in advance, on multiple floors in both buildings,
while suffering no adverse effects from the planes’ impact with these same areas.

This is impossible

Read the rest here: http://www.implosionworld.com/Article-WTC%20STUDY%208-06%20w%20clarif%20as%20of%209-8-06%20.pdf

[Rohirrim]

Furthermore:

Protec is one of the world’s most knowledgeable independent authorities on explosive
demolition, having performed engineering studies, structure analysis, vibration/air
overpressure monitoring and photographic services on well over 1,000 structure blasting
events in more than 30 countries. These include the current world record-holders for
largest, tallest and most buildings demolished with explosives. Protec regularly
documents the work of more than 20 explosives contractors who perform structure
blasting as a primary source of revenue (including extensive experience with every
American company) as well as dozens more who blast structures in a part-time capacity.

Beyond the above, Protec possesses several additional types of data and experience
that place the firm in a unique position to analyze and comment on this event:

1. Protec was operating portable field seismographs at construction sites in
Manhattan and Brooklyn on 9/11, and these seismographs were recording
ground vibration throughout the timeframe of events at Ground Zero. These
measurements, when combined with more specific and detailed seismic data
recorded by Columbia University’s Lamont-Doherty Earth Observatory, help to
provide an unfiltered, purely scientific view of each event.

2. In the weeks following 9/11, several Protec building inspectors and staff
photographers, including this author, were contracted by demolition teams to
document the deconstruction and debris removal processes at Ground Zero.
These processes included the mechanical pull-down of the remains of the U.S.
Customs Building (WTC 6) and various other activities occurring simultaneously
throughout the site. Our teams took thousands of photographs and personally
examined untold amounts of debris, including countless structural elements from
WTC 1 and 2. While these photographs and video recordings were not originally
intended to specifically prove or disprove evidence of explosive demolition, they
do provide substantial visual evidence that relates directly to this analysis and
place us in a position to speak first-hand of conditions on site rather than relying
on outside testimony or hearsay.

3. Protec has been given access to thousands of personal photographs taken by
laborers and site foremen employed by the demolition companies responsible for
deconstructing the Ground Zero site. The companies include Tully Construction,
D.H. Griffin Wrecking, Mazzocchi Wrecking, Yannuzzi Demolition, Gateway
Demolition and Manafort Brothers. (Any other demolition company claiming to
have worked on the Ground Zero site either worked under the supervision of one
of these firms or is misrepresenting their participation.) In addition, Protec
documented the only public discussion of the 9/11 clean-up attended by all of the
demolition teams (National Demolition Association Convention, Orlando, Florida,
4/22/03). While the original intent of Protec’s two-hour video was to archive the
unprecedented challenges faced by these teams, various questions and
commentary from the speakers are relevant to this analysis.

4. Because building implosions are often promoted as live news events, Protec’s
offices are equipped to record multiple television broadcasts at all times. Our
company’s archived recordings of original news broadcasts from the morning of
9/11 begin well prior to the collapse of the first tower and continue uninterrupted
beyond the collapse of WTC 7. These original unedited recordings have allowed
us to compare and scrutinize the collapse of all three structures free from any
possibility of image tampering or modification. In addition, we have examined
dozens of freelance and amateur video recordings incorporated into various
documentary programs chronicling 9/11 and studied countless ground-based and
aerial images captured by private, press and government-contracted
photographers.

Feel free to debunk them, Gaff.

[mhgaffney]

yeah yeah. Nothing new here.

Don't you think it is kind of curious that Protec just happened to be operating portable seismic equipment in NYC on 9/11?

It seems curious to me.

Did you look into Blanchard? Did you check this out?

I can answer the question for you. No.

[Rohirrim]

yeah yeah. Nothing new here.

Don't you think it is kind of curious that Protec just happened to be operating portable seismic equipment in NYC on 9/11?

It seems curious to me.

Did you look into Blanchard? Did you check this out?

I can answer the question for you. No.

Blanchard is a demolitions expert. In fact, he wrote a book well reviewed by the industry called "The History of Demolition." You have facts to show he isn't an expert? Perhaps Protec was monitoring seismic equipment in Manhattan because THAT'S THEIR BUSINESS. Gee, ya think? In fact, here's a funny little idea for you. I'll bet if you went wandering around in Manhattan right now, you'd find some Protec employee monitoring vibrations at some construction site. Where I work, we are undergoing massive construction. A whole new wing. There are various guys walking around with monitoring equipment at all times. I wouldn't be surprised if one of them is a Protec employee. I did go to 911 Research's "debunking" of Blanchard's paper. I especially liked this paragraph:

More important, Blanchard's denials serve to confuse the distinct issues of evidence of explosives and evidence of demolition. If the WTC towers were not felled by natural collapses, then their destruction must have been engineered -- ie: subjected to controlled demolition. Thus, arguments that contradict the possibility of natural collapses imply the use of controlled demolitions, while implying nothing about how they were engineered, and indeed the possibilities are endless.

I challenge any English speaker to parse out the meaning of that little gem. They also didn't like his use of the word "scientific" so often. I'm sure that's a word they find generally irritating.

[W*GS]

gaffney at work:

http://flushdoggy.com/wordpress/wp-content/uploads/2008/10/honey.jpg

[Bronco_Beerslug]

Sorry but I have to cry "Bull****!"

Beerslugger just posted (above) a lengthy piece of the early article by Dr Thomas Eagar, with whom he apparently agreed. Why else post it?

I pointed out that NIST rejected Eagar's collapse model in its final report.

Now Beerslugger retreats from his post faster than the roadrunner.

You can't have it both ways.

Beerslugger lashes out reflexively -- like a knee jerk -- at anyone or anything that impinges on his comfort zone.

MHGLike I said, your reading comprehension shows you suck at this. Both NIST and Eager use the term "pancaking" to describes floors collapsing. You're the one trying to have it both ways and you make very piss poor attempts at it. First you cite NIST (I then post actual NIST findings) and then you call BS on it. Every time you "point out" something I post the actual information which shows you to be a blundering fool.

[Rohirrim]

Isn't the Gaff going to come back and debunk my posts?

Hello....


Is this thing on?

[Rohirrim]

Do you hear anything?





crickets

[mhgaffney]

I looked at Blanchard's stuff way back.

It stinks. Do you have a nose?

There are only about a half dozen to a dozen demolition companies on the planet capable of taking down a building the size of the WTC. One of them had to be in on it.

Do you finally get it?

Look - if you are skeptical - why don't you contact Blanchard and ask him to comment on the discovery of residues of high temperature explosives in the dust. I'd be curious at his reaction.

If you are hearing crickets -- maybe they are real crickets.

Or maybe you need to see a doctor.

[Rohirrim]

I looked at Blanchard's stuff way back.

It stinks. Do you have a nose?

There are only about a half dozen to a dozen demolition companies on the planet capable of taking down a building the size of the WTC. One of them had to be in on it.

Do you finally get it?

Look - if you are skeptical - why don't you contact Blanchard and ask him to comment on the discovery of residues of high temperature explosives in the dust. I'd be curious at his reaction.

If you are hearing crickets -- maybe they are real crickets.

Or maybe you need to see a doctor.

Oh, I get it. Blanchard and Protec were in on it! It's so obvious now. Anybody who doesn't buy into the troofer fantasy was in on it! But wait a minute... I don't believe any of that crap and I wasn't in on it...

at least I don't remember it...


Maybe I'm a Manchurian candidate?

[mhgaffney]

Ro,

I am simply suggesting that you take a closer look at what Blanchard is saying. It does not add up.

Exercise the same skepticism with Blanchard and the official story - that you show regarding critics like me -- and you will quickly see who is correct.

I think Blanchard is pushing your buttons -- telling you what you want to hear.
MHG

[Rohirrim]

Ro,

I am simply suggesting that you take a closer look at what Blanchard is saying. It does not add up.

Exercise the same skepticism with Blanchard and the official story - that you show regarding critics like me -- and you will quickly see who is correct.

I think Blanchard is pushing your buttons -- telling you what you want to hear.
MHG

Look, a bunch of Saudi zealots and mad dogs using box cutters, hijacked U.S. airliners full of innocent people and flew them into buildings. It was the act of lunatic suicide bombers. The buildings fell down. One plane was flown into the ground when the passengers heroically tried to retake control. Two conspiracies were uncovered starting that day. One, our CIA and FBI were so inadequate, mismanaged and pathetic that they couldn't stop even this most primitive plot. Basically, their institutional infighting allowed this disaster to happen. THAT should be one major investigation - and heads should have rolled for it. Second, George Bush and his neocon cabal used 911 to invade a country that had nothing to do with it. THAT should have been investigation number two, and heads should have rolled for that. This chasing of unicorns by the troofers has served the true criminals in this affair well by misdirecting the focus away from their malfeasance.

[SPfloppy]

This is emensely entertaining. But for myself I allow the easiest answer to be the likliest candidate for being the right answer. Airplanes colliding with large structures were the initial cause and the collapse was the effect. The proceeding invasions and finger pointing/undermining/political bickering/by both the left and the right were opportunistic a$$hole moves that shamelessly capitalized on a horrific tragedy. No-one inside the US government was responsible for the attacks as a conspiracy. But almost everyone with any agenda has used 911 to make thier name off off the name of almost 4,000 dead. Al Queda are dicks for attacking, Bush was a dick for inciting support for Iraq by beating the 911 drum and the democrats have used all of thee above to Bash Bush, the CIA, the FBI and to gain votes and seats in houses of government.