posted 10-09-2003 08:06 PM            

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Thankfully, I found this note on the BBC web page "Fire reaches 800 [degrees] C -- hot enough to melt steel floor supports."
That is one of the things I warned you about: In the 20th Century, steel melted at 1535 degrees Celsius (2795 F), but in the 21st Century, it melts at 800 degrees C (1472 F).
This might be explained as a reporter's mistake -- 800 to 900 C is the temperature for forging wrought iron. As soft as wrought iron is, of course, it would never be used for structural steel in a landmark skyscraper.

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But then lower down, the BBC page repeats the 800 C number in bold, and the article emphasizes that the information comes from Chris Wise, "Structural Engineer." Would this professional individual permit himself to be misquoted in a global publication?

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Eduardo Kausel, an M.I.T. professor of civil and environmental engineering, spoke as follows to a panel of Boston area civil and structural engineers: "I believe that the intense heat softened or melted the structural elements -- floor trusses and columns -- so that they became like chewing gum, and that was enough to trigger the collapse." Kausel is apparently satisfied that a kerosene fire could melt steel -- though he does not venture a specific temperature for the fire

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Images cached from BBC page . Items indicated in Clifton image (right): 13. Exterior columns; 17. Interior columns; 20. Usable office space
BBC News Image (left) is misleading:
1. A "beam" is always horizontal, "columns" are vertical. The vertical steel supports in the core were columns.
2. The central columns occupied about 25% of the floor area, not 10% as is shown on the left. (that depends on what floor you are on, - WL)
3. The central columns were not encased in a single block of concrete, but interspersed with elevator shafts

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This drawing shows the two WTC towers (black) and the paths of the attacking aircraft (red). Within the profile of each tower, the shape of the central core is shown by the green rectangle. WTC buildings 1 through 6 are numbered, WTC 7, north of 6, is not shown.

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Actually that is a handy drawing to illustrate an important difference in the impacts of the two planes. As the plane struck the north building it‚s mass (including the fuel) penetrated straight through to the core. While the perimeter columns had the floor slabs behind them to provide them with some resistance to the lateral force of the impact, the interior core columns and beams did not have this advantage. Therefore it is quite probable that these columns and beams were extensively damaged by the force of the impact. In addition, the plane penetrated straight in much like a puncture wound in flesh.
The second plane struck at an angle with a slicing motion. In addition, much has been made o the jet fuel that exited and burned outside the building on impact. But if you look at that drawing and think about it, you will realize that the left wing, which held half the fuel, would have struck across the core area.

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With the central core bearing the weight of the building, the platters were tied together and stabilized by another set of steel columns at the outside rim, closely spaced and completely surrounding the structure. This resulting structure was so stable that the top of the towers swayed only three feet in a high wind. The architects called it a "tube-within-a-tube design."

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Here is another misleading statement by McMicheal. The weight of the building was born by both the core and the perimeter columns.
I think he is trying to say that floor slabs are like platters of old LPs on a record spindle. If so, then he has no concept of how a building framework works.

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The TV experts told us that the joints between the floors and central columns melted (or the floor trusses, or the central columns, or the exterior columns, depending on the expert) and this caused the floor to collapse and fall onto the one below. This overloaded the lower floor, and the two of them fell onto the floor below, and so on like dominos

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I do not know the exact specifications for the WTC,

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posted 10-09-2003 08:13 PM            

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Where the radial trusses connected with the central columns, I imagine the joints looked like the big bolted flanges where girders meet on a bridge -- inches thick bolts tying the beams into the columns.
In order to weaken those joints, a fire would have to heat the bolts or the flanges to the point where the bolts fell apart or tore through the steel.

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But here is another thing that gives me problems -- all the joints between the platter and the central columns would have to be heated at the same rate in order to collapse at the same time - - and at the same rate as the joints with the outer columns on all sides -- else one side of the platter would fall, damaging the floor below and making obvious distortions in the skin of the building, or throwing the top of the tower off balance and to one side.
But there were no irregularities in the fall of those buildings. They fell almost as perfectly as a deck of cards in the hands of a magician doing an aerial shuffle.

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This is particularly worrisome since the first plane struck one side of the north tower, causing (you would think) a weakening on that side where the exterior columns were struck, and a more intense fire on that side than on the other side. And the second plane struck near the corner of the south tower at an angle that caused much of the fuel to spew out the windows on the adjacent side
Yet the south tower also collapsed in perfect symmetry, spewing dust in all directions like a Fourth of July sparkler burning to the ground
This symmetry of descent is even more remarkable in the south tower because in the first moments of the collapse, the top 20 floors of the south tower tilted over to the south

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_Whatever irregularities caused the top f the tower to tilt, subsequent pictures show the tower falling mostly within its own footprint. There are no reports of this cube of concrete and steel from the upper floors (measuring 200 ft. wide, 200 ft. deep, and 250 ft high) falling a 1000 feet onto the buildings below.

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I have recently seen a videotape rerun of the south tower falling. In that take, the upper floors descend as a complete unit, tilted over as shown on the BBC page, sliding down behind the intervening buildings like a piece of stage scenery.
That scene is the most puzzling of all. Since the upper floors were not collapsed (the connection between the center columns and the platters were intact), this assembly would present itself to the lower floors as a block of platters WITHOUT a central hole. How then would a platter without a hole slide down the spindle with the other platters? Where would the central columns go if they could not penetrate the upper floors as the platters fell?

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If the fire melted the floor joints so that the collapse began from the 60th floor downward, the upper floors would be left hanging in the air, supported only by the central columns.

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This situation would soon become unstable and the top 30 floors would topple over (to use Loizeaux's image) much like felling the top 600 ft. from a 1,300 ft. tree.
This model would also hold for the north tower. According to Chris Wise's "domino" doctrine, the collapse began only at the floor with the fire, not at the penthouse. How was it that the upper floors simply disappeared instead of crashing to the earth as a block of thousands of tons of concrete and steel?

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posted 10-09-2003 08:15 PM            

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In trying to reconstruct and understand this event, we need to know whether the scenes we are watching are edited or simply shown raw as they were recorded.
But let us return our attention to the fire. Liquid fuel does not burn hot for long. Liquid fuel evaporates (or boils) as it burns, and the vapor burns as it boils off. If the ambient temperature passes the boiling point of the fuel and oxygen is plentiful, the process builds to an explosion that consumes the fuel.
Jet fuel (refined kerosene) boils at temperatures above 160 degrees Celsius (350 F) and the vapor flashes into flame at 41 degrees Celsius (106 F). In an environment of 1500 degrees F, jet fuel spread thinly on walls, floor, and ceiling would boil off very quickly.

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If there were sufficient oxygen, it would burn; otherwise it would disperse out the open windows and flame when it met oxygen in the open air -- as was likely happening in the pictures that showed flames shooting from the windows. (what about when the superheated vapor escaped up the building? ˆ W.L. ) Some New Yorkers miles distant claimed they smelled the fuel, which would indicate fuel vapors were escaping without being burned.
Note that jet fuel burning outside the building would heat the outside columns, but would not heat the central load-bearing columns significantly. Following this reasoning, the jet fuel fire does not adequately explain the failure of the central columns.

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Whether the fuel burned gradually at a temperature below the boiling point of jet fuel (360 C), or burned rapidly above the boiling point of jet fuel, in neither case would an office building full of spilled jet fuel sustain a fire at 815 degrees C (1500 F) long enough to melt 200,000 tons of steel. And certainly, the carpets, wallpaper, filing cabinets, occasional desks -- nothing else in that office was present in sufficient quantity to produce that temperature.

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The WTC was not a lumber yard or a chemical plant. What was burning?

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OK, since it was mentioned, I am also upset with the quantity of concrete dust. No concrete that I have ever known pulverizes like that. It is unnerving. My experience with concrete has shown that it will crumble under stress, but rarely does it just give up the ghost and turn to powder. But look at the pictures -- it is truly a fine dust in great billowing clouds spewing a hundred feet from the collapsing tower.

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posted 10-09-2003 08:20 PM            

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I need a faith booster shot. I would like to find a picture of all those platters piled up on the ground, just as they fell -- has anyone seen a picture like that? I am told it was cumulative weight of those platters falling on each other that caused the collapse, but I don't see the platters piled up like flapjacks on the ground floor.

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I have just one other point I need help with -- the steel columns in the center. When the platters fell, those quarter-mile high central steel columns (at least from the ground to the fire) should have been left standing naked and unsupported in the air, and then they should have fallen intact or in sections to the ground below, clobbering buildings hundreds of feet from the WTC site like giant trees falling in the forest. But I haven't seen any pictures showing those columns standing, falling, or lying on the ground. Nor have I heard of damage caused by them.

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"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.

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Romero is a former director of the Energetic Materials Research and Testing Center at Tech, which studies explosive materials and the effects of explosions on buildings, aircraft and other structures.
Romero said he based his opinion on video aired on national television broadcasts.
Romero said the collapse of the structures resembled those of controlled implosions used to demolish old structures.
"It would be difficult for something from the plane to trigger an event like that," Romero said in a phone interview from Washington, D.C.
Romero said he and another Tech administrator were on a Washington-area subway when an airplane struck the Pentagon.

He said he and Denny Peterson, vice president for administration and finance, were en route to an office building near the Pentagon to discuss defense-funded research programs at Tech.
If explosions did cause the towers to collapse, the detonations could have been caused by a small amount of explosive, he said.

"It could have been a relatively small amount of explosives placed in strategic points," Romero said.
The explosives likely would have been put in more than two points in each of the towers, he said. But Romero recanted ten days later and admitted the whole thing was perfectly natural and unsurprising. I wonder what happened in those ten days to make him so smart on the subject so quickly.

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It is interesting to note the two part nature of his little treatise. Apparently after the errors in first part of his theory were pointed out to his, he felt the need to further justify his conclusions in part 2, below.

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The critics have pointed out that steel does not MELT at 1500 F, but it does soften and lose its strength, enough to cause the towers to collapse. We are asked to believe, as one Australian put it, that steel supports turn to licorice when heated in a fire.

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Note that structural steel at 550 degrees C (1022 F) has 60% of the strength of steel at normal temperatures. This weakening of steel when heated is supposedly responsible for the catastrophic collapse of the towers. The statement generates three questions to be answered in order to determine whether this phenomenon could cause the collapse of the World Trade Center:
1. How much strength would the steel have to lose for the WTC to collapse?
2. What temperature would the steel have to reach to occasion this loss of strength?
3. What was the temperature of the fire in the WTC; i.e., did it reach the critically weakening temperature?
Question 1:
In the original article, I cited my own experience that a support device must be capable of bearing three times the maximum load that would ever be applied.
It turns out that this rule-of-thumb is applicable only to dynamic loads, not static (structural) loads of commercial buildings. Since then, I have been informed by a commercial structural engineer that the standard ratio for static loads is five, not three. That is, if a bridge is rated to carry 1 ton, it should be capable of bearing 5 tons without collapsing at the time the bridge is built.
Going back to the fire at the WTC, we can see that reducing the steel structure to 60% its rated strength should NOT have weakened it to catastrophic collapse, because at 60% it would still support three times the rated load. The steel structure would have to be reduced to 20% of its rated strength to collapse.
Thus, even if the fire had heated the steel to 550 degrees C (1022 F), that would not have been sufficient to cause the towers to collapse.

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Question 2:
The Corus page on fire vs. steel supports ({ HYPERLINK "http://www.corusconstruction.com/fire/fr006.htm" }http://www.corusconstruction.com/fire/fr006.htm) shows that the steel would have to be heated to about 720 degrees C (1320 F) to weaken the steel to 20% of its cool strength.
The text on that page discusses another change in the steel above 550 degrees C (1022 F): It looses elasticity and becomes plastic. Elasticity means that when the steel is bent, it returns to its original shape; it springs back. Plasticity means that the steel is permanently deformed and does not spring back to the original shape.

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Springing back or not, our only concern with this page is to determine the point on the graph where the steel would be weakened to 20% its original strength, and that point is 720 degrees C (1320 F).
For steel, 550 degrees C (1022 F) is an important threshold, however, and we should not be glib with it. If a steel tower were heated to 550 C, loss of elasticity could mean that the tower would not spring back to the original shape after a gust of wind, and a series of buffets might cause the tower to fail -- if the strain exceeded the reduced strength of the hot steel.
Question 3:
Now let us make a guess on the actual heat of the fire.
Fortunately, a number of studies have been done under very similar conditions. In Europe, multi-storied "car parks" are often built of steel, and the possibility of vehicle fire is a distinct possibility. A parked vehicle, loaded with gasoline, diesel, tires, engine oil, engine tar, upholstery, hydraulic fluid, etc. can cause a fire that seems very hot. A number of other vehicles could be parked close to the burning one, and they too could catch fire, with a general conflagration. Any number of cars could contain almost any household items from shopping, etc.
These materials are similar to the materials we would expect in the burning offices of the WTC: jet fuel (which is a refined kerosene, very similar to the diesel used in some European cars), oil, upholstery, etc.
A summary of the results of these studies is published on the Corus page. Go to { HYPERLINK "http://www.corusconstruction.com/" }http://www.corusconstruction.com/ and click on "Fire". Individual articles are listed across the top of the window. The fourth article, "Fire in Car Parks," discusses the temperatures of "any fires that are likely to occur" in a car park ({ HYPERLINK "http://www.corusconstruction.com/carparks/cp006.htm" }http://www.corusconstruction.com/carparks/cp006.htm).
Presumably, one car could catch fire and inflame other cars parked closely nearby. As explained below, "The maximum temperatures reached [in actual test fires] in open sided car parks in four countries" was 360 degrees C (680 F), and structural steel has "sufficient inherent resistance to withstand the effects of any fires that are likely to occur."

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Here is the relevant paragraph, complete: "Steel-framed car parks have been rigorously fire tested in a number of countries (Table 3). These tests demonstrate that most unprotected steel in open sided steel-framed car parks has sufficient inherent resistance to withstand the effects of any fires that are likely to occur. Table 3 lists the maximum temperatures reached in open sided car park tests in four countries. These can be compared with the characteristic failure temperatures for beams carrying insulating floor slabs and columns of 620 [degrees] C and 550 [degrees] C respectively."
Note that the description does not limit the duration of the fire. >From this it does not appear to matter whether the fire burned all week or just for two hours. No mention is made, as some people have suggested (from erroneous interpretation of other graphs involving time), that prolonged heat brings about progressive weakening of steel.

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A fire in a steel car park is a very imprecise event, and the heating of the steel supports varied widely in the tests. The temperature of (horizontal) beams varied from 226 C in the USA to 340 C in Australia; and the temperature of (vertical) columns varied from 242 C in Japan to 360 C in the UK. None of the steel was protected with the thermal insulation that is commonly used in office buildings, including the WTC.
To my mind, this is definitive answer: the maximum temperature in the unprotected steel supports in those test fires was 360 degrees C (680 F), and that is a long way from the first critical threshold in structural steel, 550 degrees C (1022 F).
Some may argue that there was much more fuel involved in the WTC events that in a car park. There was also much more steel involved, the support columns were more massive, and they were protected with insulation.

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posted 10-10-2003 04:45 AM            

the official tale:
>Unfortunately unprotected steel warps, melts, sags and collapses when heated to normal fire temperatures about 1100 to 1200 degrees F.<
>When the jet liners crashed into the towers based upon knowledge of the tower construction and high-rise firefighting experience the following happened: First the plane broke through the tubular steel-bearing wall. This started the building failure. Next the exploding, disintegrating, 185-ton jet plane slid across an open office floor area and severed many of the steel interior columns in the center core area. Plane parts also crashed through the plasterboard-enclosed stairways, cutting off the exits from the upper floors. The jet collapsed the ceilings and scraped most of the spray-on fire retarding asbestos from the steel trusses. The steel truss floor supports probably started to fail quickly from the flames and the center steel supporting columns severed by plane parts heated by the flames began to buckle, sag, warp and fail. Then the top part of the tower crashed down on the lower portion of the structure. This pancake collapse triggered the entire cascading collapse of the 110-story structure.<
http://vincentdunn.com/wtc.html

for a building with temperatures high enough to cause steel to fail...
People who were stronger than steel were active up until the sudden collapse;
or the temperatures were not as high as the official tale claims. http://www.mishalov.com/wtc_rescueplan.html
http://www.freerepublic.com/focus/fr/606822/posts http://abcnews.go.com/Sept11_2003/

When Chief Palmer radioed from the 78th floor,...
Chief Palmer could see only two pockets of fire, and called for a pair of engine companies to fight them.

the impact zone, which ran from the 78th to the 84th floors.

source:
Lost Voices of Firefighters, Some on 78th Floor
New York Times, August 4, 2002
By JIM DWYER and FORD FESSENDEN http://www.mishalov.com/wtc_lostvoicesfiredept.html

accounts from the north tower:
(10:28 a.m. — North tower of trade center collapses.)
>``I'm OK. I'm on the 106th floor. It's filled with smoke and we can hardly breathe.'' <
http://www.mishalov.com/wtc_northtower.html
accounts from the south tower:
>(105th floor) They couldn't breath where he was. I was about to ask him who are the people with you, that's when we both saw it. We both said, ``Oh no, I love you darling.'' The line dropped and the building fell. <
(9:59 a.m. — South tower of trade center collapses.)
http://www.mishalov.com/wtc_southtower.html
visit the links above.
Read about people on cellphones talking while supposedly:
>The jet collapsed the ceilings and scraped most of the spray-on fire retarding asbestos from the steel trusses. The steel truss floor supports probably started to fail quickly from the flames and the center steel supporting columns severed by plane parts heated by the flames began to buckle, sag, warp and fail.<

The idea that fires caused steel to fail is proven false because people were still talking on cell phones and radios when the buildings fell.

Who believes people can talk while temperatures around them are hot enough for steel to suddenly fail?
the official tale:
>Unfortunately unprotected steel warps, melts, sags and collapses when heated to normal fire temperatures about 1100 to 1200 degrees F.<

Wanna buy a bridge real cheap?

Even the testimony of Rev. Picarello
is also consistent with controlled demolitions,
as witnesses hear sequentially detonated FLSCs cutting supports.
"bap, bap, bap, bap!"

> I began to hear a rumbling sound. I didn't know what to think at the time. The rumbling was getting louder when the ground started to shake. At this point I looked up over my shoulder and to my shock and at the same time to my horror, the North Tower was beginning to come down.
As it started to collapse I could see that huge antenna atop the building moving one way and then the next as the tower began collapsing. It began to pancake making very loud crumbling sounds "bap, bap, bap, bap!" ...as each floor would collapse upon the other. I looked up at huge amounts of fire and debris being forced away from the building as it began to come down. It appeared to be coming right for me. < http://houseontherocksi.org/wtc.htm

Just like those people talking on cell phones.
The Reverend somehow failed to notice all that jet fuel pouring down elevator shafts and stairwells.
Failed to notice the building around him heated to about 1100 to 1200 degrees F.

Chief Palmer could see only two pockets of fire, despite the official story about an inferno of burning office furnishings, computers and paper;
Despite the pools of jet fuel of the official story.

the official story proven false by chief Palmer's expert testimony.
Proven false by the testimony of eyewitnesses.
We must therefore seek an explanation for the towers sudden collapse which fits the recorded events and testimony of witnesses.

One theory does fit all events,
all testimony,
all video evidence:
controlled demolition.

Let us remember the sole contractor hired for cleanup at the WTC.
http://www.controlled-demolition.co.uk/web/explosive_home/explosive.asp

High rise explosive demolition experts!

Visual evidence of controlled demolition: http://thewebfairy.com/911/demolition/controlled.htm
Includes links to videos of controlled demolitions for comparison.
http://www.911-strike.com/demolition_explosive.htm
http://www.whatreallyhappened.com/wtc7.html

Romero's reversal: http://www.rense.com/general17/eyewitnessreportspersist.htm

>One eyewitness whose office is near the World Trade Center told AFP that he was standing among a crowd of people on Church Street, about two-and-a-half blocks from the South tower, when he saw "a number of brief light sources being emitted from inside the building between floors 10 and 15." He saw about six of these brief flashes, accompanied by "a crackling sound" before the tower collapsed. Each tower had six central support columns.

One of the first firefighters in the stricken second tower, Louie Cacchioli, 51, told People Weekly on Sept. 24: "I was taking firefighters up in the elevator to the 24th floor to get in position to evacuate workers. On the last trip up a bomb went off. We think there were bombs set in the building."

Kim White, 32, an employee on the 80th floor, also reported hearing an explosion. "All of a sudden the building shook, then it started to sway. We didn't know what was going on," she told People. "We got all our people on the floor into the stairwell . . . at that time we all thought it was a fire . . .We got down as far as the 74th floor . . . then there was another explosion." <

posted 10-10-2003 12:12 PM            

Excellent logic and links, Shatoga, and Larson, A for effort for your rebuttles to the fire situation. I am grateful for your reading and addressing each issue!

But as any who's reading can see, the testimonies of those who were there do not sustain or support the super high temp theory.

The chimney theory does not hold when people were accessing the stairways which I assume were centrally located. If the air was sucked up the central cavity or the cavity itself was "on fire", then why wasn't there a wind or force connected to it or the heat so high in the central columns that people could not navigate? And what about the survivor who left the building just before its collapse when he was burned and jettisoned across a boulevard? How does this correlate with the sucking action of a chimney stack? And this was befoe the collapse!

We have some opposing information here, not to mention people hearing explosions on various floors, survivors and non.

Another point of logic? If only one or two floors burned and lost strength and the floors on top and below were intact, why didn't flattened objects and large chunks of steel and concrete remain? Gravity alone does not explain the destruction of these buildings.

The eyewitness accounts are the missing pieces of information that is truly needed this destructive equation.And Shatoga gave quite a few!

There are those who have pictures of explosives on specific floors. I viewed the pics on these. The helicopter that was viewing from a horizontal position to the towers also experienced a shock wave and viewed flashing lights from various floors -- also filmed.

I'm still tired of researching and will leave it up to you two until I get my steam going.

Question for Larson:

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Actually there were irregularities in both of the colapses

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What irregularities?

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This is particularly worrisome since the first plane struck one side of the north tower, causing (you would think) a weakening on that side where the exterior columns were struck, and a more intense fire on that side than on the other side. And the second plane struck near the corner of the south tower at an angle that caused much of the fuel to spew out the windows on the adjacent side
Yet the south tower also collapsed in perfect symmetry, spewing dust in all directions like a Fourth of July sparkler burning to the ground
This symmetry of descent is even more remarkable in the south tower because in the first moments of the collapse, the top 20 floors of the south tower tilted over to the south

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Larson:

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Does he just contradict himself here? First he says that there was no irregularity, then he says that there was.

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No he doesn't. What he expected was the tilting tower to fall like a tree would fall and also to create force on the remaining lower structure. But the downward motion, like you said, over-powered the leaning action and it failed to topple. The question is: What caused the collapse at such a great speed? The only explanation to that is demolition. If each floor collapsed through gravity alone, the crunching of each floor would occur and the process would have proceeded much more slowly through time as forces had to be considered, slowly at first and then faster as the weight accumulated. In the gravity case, the upper portion of the building would have toppled because it's action had already started and a gravity situation would have had to contend with the forces of opposition in the lower floors. But the descent mimics that of a controlled demolition rather than a gravity descent due to its speed from mili-second one and the lack of force upon the remaining structure! If we could set up two computer controlled scenarios, one with demolition and one with mere gravity -- wouldn't the two differ in terms of time? This may be a Newtonian question, but it could be a key to explanation. And, at the same time that the upper floors (South Tower tilting) were focusing weight on one side of the building (through its falling motion) this action itself didn't seem to destablize the building in an irregular way, instead, the downward motion took over. At the instant the upper floors began to topple, an equal or opposing force should have worked upon the remaining building if it was so weakened. But it didn't -- proving the strength of the remaining structure and also marking the moment of no return and demolition trigger because if the upper part of the building had been allowed to fall, it would have acted on the column standing and or toppled and created much more surrounding damage. You see? It was at that moment that the controller of demolition had to proceed or the lateral destruction of the falling upper floors would have destroyed nearby buildings to an unplanned degree, breaking promises to those who signed contracts and leased neighboring buildings adjacent to the WTC. This was the South Tower.

Realizing the time had come, the North Tower was then detonated, even though many experts claimed the damage done to the interior core of the North Tower was more extensive due to the greater penetration of the plane.

Why didn't the North Tower collapse first then, if the damage was more extensive than that done to the South Tower?

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Actually the video images show that the antenna mast on top of the building began to sag a second before the main collapse began. To me this indicates that unlike the south tower where the collapse apparently originated on the damaged perimeter, the collapse of the north tower began with the failure of the core columns.
This is entirely logical give the nature of the impact of each plane.

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Yes. But why didn't the North Tower collapse first if it sustained more damage to the core?

Why do windows blowing out represent weakness in steal outer structure to you, Larson?

I said there was no evidence of steel outer structure weakness in the lower floors, no buckling and you respond with windows? Windows blowing out could mean explosive forces of both jet fuel and explosives! Windows breaking could also mean a jolting from the impact disrupting the integrity for a moment, but not in the long term as the towers standing for the length of time they did, testifies. And who knows how long they would have stood without demolition?

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I don‚t know, I have personally witnessed the controlled demolition of several high rise housing projects and believe me, the dust flys when the building crumbles.
Furthermore these were buildings were all of the friable materials had already been removed. In the towers materials such as drywall and fireproofing were still present when they went down.

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It was more like a pyroclastic gaseoues and dust cloud than just dust! It radiated out for blocks and blocks unlike mere falling buildings which do create dust. Wouldn't objects just smash rather than be totally pulverized into dust if the towers just fell due to gravity?

There are sites on the composition of the dust itself, but I don't have the energy right now to peruse them. I will later.

Enough for now.

In truth,

bc

posted 10-10-2003 02:06 PM            

In one of my posts above I note how high strength bolts can over temper when exposed to fire temps (Bolts are quenched from around 850°C and this creates an extremely hard but brittle structure. They are then subsequently tempered between 475°C to 600°C to restore some ductility but with a measured loss in strength. If these temperatures are then exceeded during a fire the bolts over temper with a resulting sharp drop in strength.) At which point the loose considerable strength.

The angle clips were welded to the exterior columns and interior beams. The trusses were bolted to the clips.

Shatoga, what happened to the 180 tons of weight from the aircraft? Lets say that the bulk of this mass wound up on one floor (about 100 tons). Do you think it likely that the force of the impact also caused the floor to buckle downward? Wouldn’t this mass have contributed to the failure of the floor?

Here is another theory. What if the weight of the aircraft was on one side of the floor on the south tower? Let us say that due to the buckling and cracking of the floor slab caused by the impact, the floor below received a considerable quantity of jet fuel. The temps of the fire caused the floor trusses to weaken and sag. These trusses are supporting the bulk of the aircraft mass. This weight pulls down the floor even more. This sag causes the direction of the load applied to the angle clips by the floor truss to change from vertical (down) to horizontal (inward). As the fire burns, the exterior columns, already compromised by the impact, begin to shift inward. The weight of the building on top of these columns accelerates the buckle and the entire side fails simultaneously.

BC

quote:

---

The chimney theory does not hold when people were accessing the stairways which I assume were centrally located. If the air was sucked up the central cavity or the cavity itself was "on fire", then why wasn't there a wind or force connected to it or the heat so high in the central columns that people could not navigate?

---

I am sorry but I don’t see your point. What evidence are you presenting that airwas not moving up the stairs? The air could have easily been moving upward while people went down. More importantly, it had to move up from the point of the fire. Furthermore, there are other shafts beside the stairs.

quote:

---

Another point of logic? If only one or two floors burned and lost strength and the floors on top and below were intact, why didn't flattened objects and large chunks of steel and concrete remain? Gravity alone does not explain the destruction of these buildings.

---

They did, at least the steel did. The concrete was thin, 4” thick, light weight concrete. It doesn’t take a lot of energy to destroy that stuff. Consider the potential kinetic energy of all of that mass that high in the air? Did you ever see the towers in person? Unfortunately, I never had the chance. But I have seen the sears tower up close. If you have ever seen these types of building up close, you wouldn’t be asking “how come more recognizable pieces didn’t survive,” you would be asking “how come as much pieces of the building survived that did?”

quote:

---

No he doesn't. What he expected was the tilting tower to fall like a tree would fall and also to create force on the remaining lower structure. But the downward motion, like you said, over-powered the leaning action and it failed to topple. The question is: What caused the collapse at such a great speed? The only explanation to that is demolition. If each floor collapsed through gravity alone, the crunching of each floor would occur and the process would have proceeded much more slowly through time as forces had to be considered, slowly at first and then faster as the weight accumulated. In the gravity case, the upper portion of the building would have toppled because it's action had already started and a gravity situation would have had to contend with the forces of opposition in the lower floors. But the descent mimics that of a controlled demolition rather than a gravity descent due to its speed from mili-second one and the lack of force upon the remaining structure! If we could set up two computer controlled scenarios, one with demolition and one with mere gravity -- wouldn't the two differ in terms of time?

---

Whew, I bet you had to ake a breath after you typed that

The tilt of the top of the tower was not a result of a lateral motion, but rather the result of the rotation of the top portion of the tower as the collapse started. This rotation was likely caused by the initial collapse starting on one side of the building. In this scenario, the axis of rotation was probably along the opposite wall (not the middle). As the weight of the building above it shifted, the columns on this wall probably went from bearing members to tension members. The load shift would have been too much for them and they would have quickly failed. This probably happened quickly, before the top had tilted more that a few degrees out of vertical. The exaggerated tilt in the picture is probably the result of the horizontal momentum from the initial shift.

However, and this is very important to understand, once the collapse started, the top portion of the building lost all structural integrity. Although this portion of the building appears to be falling as an intact unit, this is an illusion. The shifting loads and stresses had already begun to break up this structure even as it fell. Therefore it is a mistake to think of this as an intact unit.

Even in actual controlled demolition projects they don’t put charges on every floor. They put a bunch at the top and let the weight of the top do the rest. Of course they usually put a few on some of the lower floors to control where the debris lands. This was NOT the case at WTC, debris was scattered in a fairly large radius about the site.

I think the problem is that most people simply don’t appreciate the value of engineering. A building made up of concrete and steel only stands because engineers have learned how to counteract weaknesses inherent in the building materials used. The WTC towers were an engineering marvel, lightweight, and magnificent. Yet these qualities also masked an inherent weakness that is common to all these types of structures.

I do not think that the towers collapse because of “controlled demolition” charges. I do, however, think that the collapse did expose some troubling assumptions and flaws in the design and construction of these types of structure.

I also think that there are engineers world wide who have built buildings using similar designs that are casting worried eyes on their work. The collapse of the WTC towers will be studied for a long time by very competent and intelligent engineers and scientists. If there is anything in their studies that indicates that anything like a controlled demolition took place, you can rest assured that this information would have surfaced by now.

quote:

---

I said there was no evidence of steel outer structure weakness in the lower floors, no buckling and you respond with windows? Windows blowing out could mean explosive forces of both jet fuel and explosives! Windows breaking could also mean a jolting from the impact disrupting the integrity for a moment, but not in the long term as the towers standing for the length of time they did, testifies. And who knows how long they would have stood without demolition?

---

Actually a window blowing out in a burning building is a classic sign that a flashover has occurred.

posted 10-10-2003 03:35 PM            

Professor. High strength bolts, not rivets.

posted 10-10-2003 07:08 PM            

Now you want to collapse a tower?

First cut the top interior supports.
the tower toppled first.

then sequentially cut each floor's interior (core) supports, then it's lower exteriro wall supports.

The collapsing roof pulls the outer walls into the void of the collapsed core.
and so on and so on
as each floor follows in a precise pattern:

First cut the core/interior supports,
then collapse the outer walls into the cavity.

Otherwise a tower falls normally.
Like a tree.
Sideways, onto adjacent structures.

Both buildings collapsed into themselves exactly like a controlled demolition.

the only time in th ehistory of the world a side impact and fire cause exactly symmetrical failure exactly like a controlled demolition.

why do i argue thus?

Controlled Demolition Inc. convinced me how difficult it is to cause an implosion instead of a falling over.

That's why!

The contractor hired by both the Clinton and Bush administrations to clean up all evidence of convenient "terrorist' bombings.

Two attacks in which professionals claimed multiple explosions,
too many witnesses left alive to speak the truth.

Operation Northwoods

posted 10-10-2003 09:21 PM            

You say the top floors of Tower 2 were already disintegrating, yet you do not prove this through video or any link. I'll watch again.

You never responded to the bomb parts of my post, either. Nor did you respond to the eye-witness accounts. Here's another one you missed on a previous post by shatoga on page 1:

quote:

---

EVIDENCE:
I have seen this "run away journalist clip" mixed into other WTC collapse sequences. Both ABC/CNN and many other TV stations made this fake-mix. That is EVIDENCE of FRAUD! They are deliberately FAKING the Video record and the TIMELINE of the WTC events!

PROOF:
I found a special version of the Clip were the "editors" forgot to "cut away" in their "video mix" ,...... which mean that in a second or two at the end of the Clip,.....the camera is "panning from behind a Car", and in the direction from North towards South,..............and there you go: BOTH TOWERS are STILL Standing TALL!!

CONCLUSION:
They were NOT running away from falling Tower debris... No, they ran away from,........ a Huge BOMB detonated at STREET LEVEL!

---

note: people were running from a cloud and blast that occured BEFORE the collapse corroborating the other witness account I mentioned.

And you never disputed any of the examples of these accounts.

Here's a question of mine you failed to answer:

Why didn't the North Tower collapse first then, if the damage was more extensive than that done to the South Tower?

Here's another one:

What irregularities?

So you concede that the structure below the impact point was stable for both buildings?

It seems Shatoga has more experience in this than you do, and he also has a video to view, frame by frame.

I'll do a little research again and post what I come up with!

Why this is so impossible for you to see is beyond me. But, I will be patient.

peace,

bc

posted 10-10-2003 09:40 PM            

http://www.abcnews4.com/news/stories/0803/100369.html





Gaithersburg, Md. (AP) - Early tests on steel beams from the World Trade Center show they generally met or were stronger than design requirements, ruling them out as a contributing cause of the collapse of the towers, federal investigators said Wednesday.

Engineers with the National Institute of Standards and Technology have conducted preliminary tests on some of the 236 pieces of steel from the wreckage, said Frank Gayle, who is leading NIST's review of the steel.

The tests found that, typical for construction steel used in the 1960s when the World Trade Center was erected, the steel beams exceeded requirements to bear 36,000 pounds per square inch. Often they were capable of bearing around 42,000 pounds per square inch.

"What that is showing us is that the steel that was applied certainly met the specifications, but was also significantly higher in some instances," lead investigator Shyam Sunder said.

A group of victims' families, the Skyscraper Safety Campaign, had complained that a majority of the beams from the site were quickly shipped off and reprocessed into new steel before it could be tested.

Sunder cautioned the NIST's results were preliminary, but said if those findings continue in further testing, that would rule out weak steel as a contributing factor in the collapse.

The steel testing was discussed Wednesday at the end of a two-day meeting with NIST officials about the Sept. 11 investigation.

The two-year probe is designed to create a model of the fire and collapse, enabling NIST, which is part of the Commerce Department, to make recommendations for improved fire and safety codes in building construction.

The Skyscraper Safety Campaign's Sally Regenhard, whose firefighter son was killed at the site, said she doubted NIST's findings.

"I don't really feel that they have a representative sample of all the steel," Regenhard said.

James Quintieri, a professor at the University of Maryland who is consulting with the Skyscraper Safety Campaign, said key questions, about the steel's strength under intense heat, and the overall design of the building, remain unanswered.

In coming months, NIST will recreate sections of the building's floor trusses, and conduct large-scale fire endurance tests on them to determine how the floors of the towers responded to the twin stresses of impact by a jet plane and a continuing fire.

The NIST group also discussed its investigation of the Rhode Island nightclub fire last February, which killed 100 people. Investigators will use the results of their investigation to make recommendations for improvements to fire and building codes.

At the meeting, some complained investigators were being delayed by prosecutors and civil lawyers denying them access to critical information, including the exact makeup of the soundproofing foam that burst into flames at the nightclub.

Lead investigator Bill Grosshandler said his team has to date gathered only about 20 percent of the information on the makeup of different materials in the building, but said it was still early in the fact-gathering process.

Others, including NIST's Dr. Jack Snell, seemed frustrated with the agency's access to information. The investigation is proceeding under an act of Congress passed last year aimed to use NIST expertise to probe building disasters.

"The whole motivation for this law was timely investigations," said Snell. "We're not doing timely investigations."

» Find More Articles Related To This One
» Search The Internet For More On This Topic

Copyright 2003 by The Associated Press.

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___________________________

Guess some testing is showing some results, heh?

posted 10-10-2003 10:02 PM            

quote:

---

Originally posted by Theh0661t:
Aren't demos placed at the base of the building?

---

the interior supports must cause the roof to collapse into the interior,
the outer walls then collapse into the void.
each floor must follow that same pattern:
the interior collapses and creates a void for the outer walls to fall into.

It requires precise co-ordination and timing;
otherwise the building will fall over
instead of falling into itself.

CDI Inc. has made that clear for many years prior to 911
at which time they began to postulate every building will spontaneously collapse into precisely controlled parameters, all by themselves.

As if CDI had lied to their clients for decades.

posted 10-10-2003 10:27 PM            

quote:

---

Originally posted by shatoga:
[QUOTE]Originally posted by Theh0661t:
[b]Aren't demos placed at the base of the building?

---

the interior supports must cause the roof to collapse into the interior,
the outer walls then collapse into the void.
each floor must follow that same pattern:
the interior collapses and creates a void for the outer walls to fall into.

It requires precise co-ordination and timing;
otherwise the building will fall over
instead of falling into itself.

CDI Inc. has made that clear for many years prior to 911
at which time they began to postulate every building will spontaneously collapse into precisely controlled parameters, all by themselves.

As if CDI had lied to their clients for decades.

[/B][/QUOTE]

Then what's all this about charges being at the BOTTOM? what's the point of that? Would that make the roof collapse?

posted 10-10-2003 10:42 PM            

The core must collapse to create a void for the outer walls to fall into..

Witnesses noted sounds and flashes of FLSCs destroying supports of upper floors as the building was brought down.

The base must be destroyed for the tower to collapse into a pile of rubble.

The entire core must collapse for all outer walls to fall into the void.

posted 10-10-2003 11:14 PM            

quote:

---

...One eyewitness whose office is near the World Trade Center told AFP that he was standing among a crowd of people on Church Street, about two-and-a-half blocks from the South tower, when he saw “a number of brief light sources being emitted from inside the building between floors 10 and 15.” He saw about six of these brief flashes, accompanied by “a crackling sound” before the tower collapsed. Each tower had six central support columns.

One of the first firefighters in the stricken second tower, Louie Cacchioli, 51, told People Weekly on Sept. 24: “I was taking firefighters up in the elevator to the 24th floor to get in position to evacuate workers. On the last trip up a bomb went off. We think there were bombs set in the building.”

Kim White, 32, an employee on the 80th floor, also reported hearing an explosion. “All of a sudden the building shook, then it started to sway. We didn't know what was going on,” she told People. “We got all our people on the floor into the stairwell . . . at that time we all thought it was a fire . . .We got down as far as the 74th floor . . . then there was another explosion.”

---

Testimony of explosions from the BBC in realtime video:
http://news.bbc.co.uk/olmedia/1535000/video/_1537692_wtc1425_evans2way_vi.ram
http://news.bbc.co.uk/olmedia/1535000/video/_1537652_wtc13_evans_vi.ram
http://news.bbc.co.uk/olmedia/1535000/video/_1537470_wtc14_rajan_vi.ram

Another link for the same steel article as above:
http://www.news8.net/news/stories/0803/100369.html

OK, I've done enough for tonight!

Sweet dreams! Hehehe!

bc

posted 10-11-2003 11:29 AM            

Check out this very short video clip from a fireman that cleaned debris at the WTC. At this link, open up the last clip at the bottom called – Fireman recalls that everything had “collapsed to dust”.
http://911research.wtc7.net/wtc/evidence/videos/index.html

Someone explain how everyting turns to dust in a building collapse. It’s also interesting how any evidence that WAS left behind was suspiciously handled and removed:

Here is an article from the editor of Fire Engineering Magazine: http://www.globalresearch.ca/articles/MAN309A.html

Here is another interesting article from a Professor of Fire Protection Engineering: http://www.newworldpeace.com/coverup5a.html

What does that tell you?

posted 10-11-2003 02:39 PM            

My degree in Mechanical Engineering from Penn State is 30 years out of date, but;
30 years spent in the Fire Protection industry gives me an expertise.

I was the person who identified the cause of the firemans' deaths in the Philly High rise fire.

Restricted orfices not installed (at fire hose racks) of standpipes in stairwells;
leaving upper floors with low pressure and inadequate water supply.

I still get yearly updates on NFPA-13

My opinions are just my opinions, but I'm not ignorant in the area of fire science.

posted 10-13-2003 10:22 AM            

quote:

---

Fire Load. First is the determination of fire load, i.e., the combustible contents, on which the fire resistance design of the building should be based. Several surveys have been carried out recently for the purpose of obtaining information on fire loads in buildings.
Fire Temperature. Assuming that the design fire load is known, the fire temperature course can be determined from a heat balance for the compartment, taking into account the heat produced and the heat losses to the walls and openings. The most important factors are fire load and the dimensions of the openings through which air, necessary for combustion of the fire load, can enter. How fire load affects fire temperature is shown in Figure 2, the influence of openings in Figure 3. It may be seen that fire load determines the duration of the fire, whereas the openings influence both intensity and duration. From this it is possible to determine the fire temperature course for a given building.

---

and

Hmm, I wonder what the addition of burning jet aircraft, complete with over 5,000 gallons of fuel does to the fire load?

The complete text is worth a read because it reflects some of the design methods and uncertainties that from the era in which the WTC towers were built.

posted 10-13-2003 10:23 AM            

Why They Fell
By Christopher M. Foley
The triumph of modern structural engineering led to tragedy when people

The triumph of modern structural engineering led to tragedy when people with evil inventions brought about unintended loading
The skyscraper has fascinated me since I first saw watercolor paintings of office buildings done by my father, a mechanical engineer with an artistic streak. The beauty of the tall building can be seen not only in its impact on the skyline but also in its structural efficiency to withstand lateral loads from earthquake and wind, as well as vertical gravity loading.
For this structural engineer, the tragedy of September 11 went beyond the horrific loss of human life. The following question continually flowed through my mind: How could the World Trade Center towers, two structures exhibiting engineering genius and visual majesty, suddenly become tombs for so many innocent people? The answer could give me and other individuals some understanding of at least one part of the tragedy.
Each tower contained about an acre of space per floor and rose 1,350 feet above the street. The design and construction of the towers can be appreciated when one considers that, combined, they contained 230 passenger elevators to move people throughout their 110 floors. Planning for the structures took nine years, and four years of demolition was required before they could begin to rise above New York. Construction averaged three floors on each tower every 10 days, and approximately 600 tons of structural steel arrived daily at the site.
The tower’s structural efficiency can be seen when one examines the hollow pierced tube system used in construction. The exterior steel columns (14 square inches) were spaced very close together (3’3” apart), and deep spandrel elements (horizontal members) formed the top and bottom of the windows. Therefore, the exterior tube of the building was essentially a solid piece of steel with holes punched in it for windows. This tube was designed to be a Vierendeel truss to resist the lateral wind loading.
The hollow pierced tube system also incorporated a central core composed of structural steel columns that housed stairways, elevators, and other service elements. The central core and exterior tube shared responsibility for supporting the vertical gravity loading. This structural system resulted in large column-free floor plans. Floor trusses supported and acted compositely with four-inch concrete slabs. These trusses spanned from the central core to the exterior tube.
The relatively thin nature of the exterior tube (14 inches thick) can be thought of, in a simplistic sense, as a soda can. One can stand on an unopened can of soda because the liquid and pressure inside “braces” the can’s sides and prevents them from buckling. However, when the liquid or pressure is removed, any small movement or slight tap on the side of the empty can cause it to “buckle” and collapse. Likewise, the exterior tubes of the WTC towers were “braced” by and eventually buckled due to the failure of the floor framing system.
To understand the collapse, one has to look at a replay of the tragic event. From the video, the aircrafts appear to be “swallowed” by the buildings. One can clearly see the flames (and most likely the wings, fuselage, etc.) passing through the interior of the building and even exiting the opposite side. Initial impact did not cause collapse of either tower thanks to a structural principle called redundancy. In simple terms, redundancy means that if a load-resisting path (in this case, the exterior tube) is compromised, other load paths are available, and therefore, collapse is prevented. When the aircraft penetrated the exterior tube, it cut some of the load paths available for the floor framing. However, the fact that the exterior tube contained many closely-spaced columns ensured that other load paths were available for floor loads to get to the foundation. Just as the exterior tube was designed as a Vierendeel truss to resist horizontal wind loading, it acted like a Vierendeel truss to span horizontally and carry the floor loading across the holes in the outer wall created by the aircraft.
As the WTC towers fought to redistribute their weight throughout the exterior tube and interior core columns down to the foundation, a very sinister element was at work—fire. The extraordinarily high-temperature fire that was burning throughout the floors adjacent to the impact zone was creating a gradual and consistent weakening of the structural framing system. It is a well-known fact that structural steel cannot survive fires for extended periods of time. Therefore, all steel building components are coated with fire-resistant materials to inhibit weakening of these elements for a period of time sufficient to allow firefighters to put out the flames. The main problem in the WTC collapse was that the fire was fed by jet fuel and not the usual sources found in office towers (e.g., paper and other combustible materials). Thus, the intensity of the fire was far greater than anything considered by the engineers.
The structural efficiency that made the towers special may also have been one reason why they collapsed. As the fire continued to burn, the interior core, the exterior tube, and the critical connections of the floor trusses were being incrementally weakened. It is conceivable that, at some point, the floor truss connections to the exterior skin failed at one or multiple floor levels. When these connections failed, it was like letting the liquid or pressure out of the soda can. The fire-weakened exterior tube began to lose its critical bracing, which could have led to the buckling or bulging of the exterior tube. Thus, there were many floors above the compromised level that now had no vertical support at the exterior of the building. These floors then became a free falling load, which initiated a progressive collapse mechanism in the towers. The towers then collapsed in a manner similar to a controlled demolition.
The natural question one might ask is: Why didn’t the bombing in 1993 take down the towers? A relatively simple answer to this question lies, once again, within the structural system. The truck-bomb parked in the garage below the tower was situated between the interior core and the exterior skin. Fortunately, the bomb was unable to compromise these critical elements.
One must understand that all structural failures of catastrophic result require many events to occur simultaneously. In the case of the WTC towers, there was the unfortunate combination of aircraft impact to the critical exterior tube with subsequent high-temperature and uncontrolled fire. The engineers who designed the WTC towers included all conceivable loadings to which the structures might be subjected. However, one can certainly understand how a jet aircraft containing passengers and filled with jet fuel flying into the upper stories of the building was not one of their design criteria.
We can always ask our engineers to design “bunker-type” building structures. The Pentagon did not suffer the same catastrophic, progressive collapse. However, would we as Americans like all our buildings to be three-story bunkers or be built exclusively underground? What would our great cities like Chicago, New York, and San Francisco look like without the mixture of short buildings, tall buildings, stadiums, and long-span bridges? Where is freedom expressed in concrete bunkers or underground tunnels? Where would we be without tall buildings? We would live in a very lifeless place, a place unworthy of being called the United States of America.

Christopher M. Foley is an assistant professor of civil and environmental engineering at Marquette University in Milwaukee, Wis.

posted 10-13-2003 01:03 PM            

The standard explanation gives the impression that the lower floors were completely intact and unaffected by the impending collapse until the exact instant that upper floors crashed down on them, one after the other.

As I see it the actual mechanics of the collapse are probably a little more complicated than that.

Think of a large, flat bottom barge being pushed across a still lake. As the flat bow of the boat pushed through the water, it creates a large bow wave which precedes it as it travels. If the lake and the draft of the barge are shallow enough, the barge can move through areas where weeds and tall marsh grasses grow up through the surface of the water. The bow wave of the barge moves and disturbs these grasses before the barge actually passes over them.

posted 10-13-2003 02:25 PM            

quote:

---

Now think of the WTC tower. As we have seen the structure consisted of perimeter and core columns braced by the floor truss and slab system. As the collapse started, the core and perimeter columns would have moved, twisted, buckled and sheered off. The floor joisted would have been pulled off of the angle clips. But here is the key part: This movement and loss of integrity of the structural members on each floor would have happened before the mass of the downward moving tower would have impacted the components. In terms of time, the lag would have been very small. But, in terms of energy, the difference is enormous. In other words, the collapse was less like a series of defined impacts floor after floor and more like a continuous rip as the failure swept though the building.

---

Your logic leaves much to be desired, Larson. If the building was "ripped" as you say, then why don't the laws of physics apply? People were leaving both buildings that WERE intact even up until the moment of collapse! You answer none of my questions and you referred to the towers as "tower" when it was obvious that the jet fuel of Tower II was mostly burned off! Your analogy of a barge on swamp water was ridiculous!

The discs on a center pole was a much closer one!

You deny that the buildings were intact under the impact sights and that amazes me!

Time and energy are directly correlated, you cannot separate them! And when you argue gravity verses demolition, you must adhere to the argument and not try to veer off into another explanation. Either the building collapsed due to gravity or it collapsed with some help. Your adding a "ripping" theory just adds another element of non-reality to it because without the weakening of underfloors due to fire, even your "ripping" theory has no teeth! Why would the ripping occur in the North Tower? And why would it collapse AFTER the South if it was more damaged by jet fuel burning? Hmmmm?

You're avoiding testimonies and common sense!

Was everyone who heard explosions hallucinating? Were those who were burned and blown across the street before the collapse, lying? Where those who took pictures of lights on various floors and experienced shock waves --- lying?

Please!

I'll now go to Shatoga's links and read!

TTFN!

bc