4um: 9/11 demolition theory challenged

An analysis of the World Trade Center collapse has challenged a conspiracy theory surrounding the 9/11 attacks.

The study by a Cambridge University engineer demonstrates that once the collapse of the twin towers began, it was destined to be rapid and total.

One of many conspiracy theories proposes that the buildings came down in a manner consistent with a "controlled demolition".

After reviewing television footage of the Trade Center's destruction, engineers had proposed the idea of "progressive collapse" to explain the way the twin towers disintegrated on 11 September 2001.

This mode of structural failure describes the way the building fell straight down rather than toppling, with each successive floor crushing the one beneath (an effect called "pancaking").

Dr Keith Seffen set out to test mathematically whether this chain reaction really could explain what happened in Lower Manhattan six years ago. The findings are to be published in the Journal of Engineering Mechanics.

Previous studies have tended to focus on the initial stages of collapse, showing that there was an initial, localised failure around the aircraft impact zones, and that this probably led to the progressive collapse of both structures.

Man stands amid rubble of the World Trade Center, AFP/Getty Once the collapse began, it was destined to be "rapid and total" In other words, the damaged parts of the tower were bound to fall down, but it was not clear why the undamaged building should have offered little resistance to these falling parts.

"The initiation part has been quantified by many people; but no one had put numbers on the progressive collapse," Dr Seffen told the BBC News website.

Dr Seffen was able to calculate the "residual capacity" of the undamaged building: that is, simply speaking, the ability of the undamaged structure to resist or comply with collapse.

His calculations suggest the residual capacity of the north and south towers was limited, and that once the collapse was set in motion, it would take only nine seconds for the building to go down.

This is just a little longer than a free-falling coin, dropped from the top of either tower, would take to reach the ground.

The University of Cambridge engineer said his results therefore suggested progressive collapse was "a fair assumption in terms of how the building fell".

"One thing that confounded engineers was how falling parts of the structure ploughed through undamaged building beneath and brought the towers down so quickly," said Dr Seffen.

The south tower of the World Trade Center collapses, AP Conspiracy theorists see evidence of a "controlled detonation" He added that his calculations showed this was a "very ordinary thing to happen" and that no other intervention, such as explosive charges laid inside the building, was needed to explain the behaviour of the buildings.

The controlled detonation idea, espoused on several internet websites, asserts that the manner of collapse is consistent with synchronised rows of explosives going off inside the World Trade Center.

This would have generated a demolition wave that explained the speed, uniformity and similarity between the collapses of both towers.

Conspiracy theorists assert that these explosive "squibs" can actually be seen going off in photos and video footage of the collapse. These appear as ejections of gas and debris from the sides of the building, well below the descending rubble.

Other observers say this could be explained by debris falling down lift shafts and impacting on lower floors during the collapse.

But no known acoustic energy of tremendous quantities occurred until the final floors collapsed. Here is a diagram that shows it:

If we had EXPLOSIONS ... those would have been recorded throughout and/or prior actual the collapse.

Well no, but if they are going around 500 mph and hit solid steel columns, guess what happens. They ARE mostly just a hollow tube of sheets of aluminum, in case you didn't know.

Are you that stupid that you think planes come out of plane crashes totally undamaged? Ok, if you believe that, then where's the undamaged airplane that hit the Pentagon, eh?

C'mon.... the lower floors (96 and 81 because the moment of horizontal impact) fell FIRST as the weight of the upper floors buckled under the upper floors.

So even though there were TRILLIONS of JOULES of energy being absorbed into the ground during the collapse, there was no seismic record of that till the last few floors hit, ok then, so it would have been impossible to detect explosives.

So what? The top STILL HAD TO FALL, and you don't judge how long the top of the building took to fall from the fall of the lower floors, you judge it from how long IT took to fall.

Show some of the seismic records that day..... you research it. It collaborates my point that demolitions were not used.

You're the one that posted there was no seismic record of the collapse, except for the last few floors. Live with it, you posted it.

As I've already stated, the faster an object is moving, the more ability it has to penetrate, damage, and destroy other objects that are harder than it is.

Examples: Melted lead bullets penetrating solid metal targets, hurricane driven straws and pieces of debris penetrating trees, bird strikes going through aircraft windshields, tens of thousands more where a softer object hitting a harder object nevertheless inflicts some major destruction.

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One of the major consequences of the 9/11 movement has been to draw enormous amounts of energy and effort away from activism directed to real and ongoing crimes of state, and their institutional background, crimes that are far more serious than blowing up the WTC would be, if there were any credibility to that thesis. That is, I suspect, why the 9/11 movement is treated far more tolerantly by centers of power than is the norm for serious critical and activist work....Noam Chomsky

Liberty is not a means to a higher political end. It is itself the highest political end.
Lord Acton

He (Gordon Duff) also implies that forcibly removing Obama, a Constitution-hating, on-the-down-low, crackhead Communist, is an attack on America, Mom, and apple pie. I swear these military people are worse than useless. Just look around at the condition of the country and tell me if they have fulfilled their oaths to protect the nation from all enemies foreign and domestic.
OsamaBinGoldstein posted on 2010-05-25 9:39:59 ET (2 images) Reply Trace

Well yes, the hollow metal airplane DID hit a few vertical columns on the way in, RIPPING it into shreds AND damaging those external columns.

HOWEVER, a hollow aluminum body is not the same as a SOLID LEAD BULLET. Sure, an incendiary .50 BMG can penetrate a manhole cover. But, a tin can travelling at the same speed as the solid lead bullet WILL NOT penetrate that manhole cover, neither will a SOLID LEAD .40 caliber pistol bullet, nor even a .308 RIFLE BULLET.

The INTERNAL steel columns which made up the internal steel core were made of MUCH heavier steel than a manhole cover, and would have sliced the airframe like a hot knife goes through butter.

Wow, it's a good thing nobody ever dropped a PC on those upper floors as that acceleration would have brought the entire building down, eh?

What it comes down to is that ONE symetrical collapse close to free fall speed would have been odd enough, but not just one, not just two, but THREE, all in the same day, where one wasn't even hit by an airplane.

Sterno poisoning must be a terrible affliction. And when the shills mix that up with their government dispensed KOOK AID I shudder to think about the havoc it plays on their alleged minds.

Liberty is not a means to a higher political end. It is itself the highest political end.
Lord Acton

Actually, many of the computers and other peripheral equipment were burn't by the initial explosions caused by jet fuel. Because the internal water sprinkler systems failed, the fires ravaged the support structures weakening the core beyond their rated stress design.

This remarck about the Easter bunny and Santa Claus was originally described by James Deffenbach, BTW .... as he can't explain anything but slap some plagiarized animated gifs from time to time on a thread.

Liberty is not a means to a higher political end. It is itself the highest political end.
Lord Acton

No way. The fires were simple office fires after the first few minutes, and the WTC had a MUCH worse fire back in the 70's yet it didn't fall down.

Possibly. I think both AGovShill and buck are trying to get a fellowship to the College of KooKology.

My GOD man ... you didn't see the initial explosions based on the impact of the jet aircraft? Every floor (above) was cut off from support systems as the fire ravaged.

You didn't see the hundreds of people leaping to their deaths because of the fires caused by the aircraft?

You two are too funny. It's as if Newton's simple experiments evaded your "profound" logic and the two of you continue to believe that bigger objects fall faster than smaller objects............and that all those floors beneath where the "collapse" began didn't offer any RESISTANCE.

Oh no, you Einstein's think that created acceleration..........HAHAHAHAHAHAHA The ONLY way you would actually have acceleration is if the RESISTANCE of the steal core were somehow severed, weakened, blown apart, cut, sliced on each and every floor. Without the complete removal of all resistance, the fall of the building is SLOWER than an object with NO resistance. This is why many physics professors call BS on the goobermint story.

"The conscious and intelligent manipulation of the organized habits and opinions of the masses is an important element in democratic society. Those who manipulate this unseen mechanism of society constitute an invisible government which is the true ruling power of our country. ... We are governed, our minds are molded, our tastes formed, our ideas suggested, largely by men we have never heard of." Edward Bernays, Father of Public Relations

They shouldn't have any problem getting a free ride to that one. They have demonstrated their usefulness to the government, especially on 9/11.

Liberty is not a means to a higher political end. It is itself the highest political end.
Lord Acton

The February 13, 1975 North Tower Fire has been carefully hidden from you. Here are a few reports concerning it.

This 110-story steel-framed office building suffered a fire on the 11th floor on February 13, 1975. The loss was estimated at over $2,000,000. The building is one of a pair of towers, 412 m in height. The fire started at approximately 11:45 P.M. in a furnished office on the 11th floor and spread through the corridors toward the main open office area.
A porter saw flames under the door and sounded the alarm. It was later that the smoke detector in the air-conditioning plenum on the 11th floor was activated. The delay was probably because the air-conditioning system was turned off at night. The building engineers placed the ventilation system in the purge mode, to blow fresh air into the core area and to draw air from all the offices on the 11th floor so as to prevent further smoke spread.
The fire department on arrival found a very intense fire. It was not immediately known that the fire was spreading vertically from floor to floor through openings in the floor slab. These 300-mm x 450-mm (12-in. x 18-in.) openings in the slab provided access for telephone cables. Subsidiary fires on the 9th to the 19th floors were discovered and readily extinguished. The only occupants of the building at the time of fire were cleaning and service personnel. They were evacuated without any fatalities. However, there were 125 firemen involved in fighting this fire and 28 sustained injuries from the intense heat and smoke. The cause of the fire is unknown.

Also, from the New York Times (Saturday 15th February 1975):

Fire Commissioner John T. O'Hagan said yesterday that he would make a vigorous effort to have a sprinkler system installed in the World Trade Center towers as a consequence of the fire that burned for three hours in one of them early yesterday morning.
The towers, each 110 stories tall and the highest structures in the city, are owned and operated by the Port Authority of New York and New Jersey, which is not subject to local safety codes.
As Commissioner O'Hagan stood in the sooty puddles of the North Tower's 11th floor hallway, he told reporters that the fire would not have spread as far as it did if sprinklers had been installed there.
The fire spread throughout about half of the offices of the floor and ignited the insulation of telephone cables in a cable shaft that runs vertically between floors. Commissioner O'Hagan said that the absence of fire-stopper material in gaps around the telephone cables had allowed the blaze to spread to other floors within the cable shaft. Inside the shaft, it spread down to the 9th floor and up to the 16th floor, but the blaze did not escape from the shaft out into room or hallways on the other floors.........
Only the 11th floor office area was burned, but extensive water damage occurred on the 9th and 10th floors, and smoke damage extended as far as the 15th floor, the spokesman said.
Although there were no direct casualties, 28 of the 150 firemen called to the scene suffered minor injuries.

More from the New York Times (Saturday 14th February 1975):

"It was like fighting a blow torch" according to Captain Harold Kull of Engine Co. 6,........
Flames could be seen pouring out of 11th floor windows on the east side of the building.

So, this was a very serious fire which spread over some 65 per cent of the eleventh floor (the core plus half the office area) in the very same building that supposedly "collapsed" on 9/11 due to a similar, or lesser, fire. This fire also spread to a number of other floors. And although it lasted over 3 hours, it caused no serious structural damage and trusses survived the fires without replacement and supported the building for many, many more years after the fires were put out.

It should be emphasized that the North Tower suffered no serious structural damage from this fire. In particular, no trusses needed to be replaced.

That the 1975 fire was more intense than the 9/11 fires is evident from the fact that it caused the 11th floor east side windows to break and flames could be seen pouring from these broken windows. This indicates a temperature greater than 700°C. In the 9/11 fires the windows were not broken by the heat (only by the aircraft impact) indicating a temperature below 700°C.

So now you know that the WTC towers were well designed and quite capable of surviving a serious fire. I repeat that this was a very hot fire that burnt through the open-plan office area of the eleventh floor and spread up and down the central core area for many floors. This was a serious fire.

Much was learned from the 1975 WTC fire. In particular, the fact that the fire had not been contained to a single floor but spread to many floors, caused much concern. The points of entry of the fire to other floors were identified and the floors of each building were modified to make sure that this would never happen again. For some strange reason, the modifications failed to perform on September 11, 2001 and again the fires spread from floor to floor.

So the building didn't fall, 'eh? What holds it up, James Deffenbach's Easter bunny or his Santa Claus?

BFD ... what does that post have to do with the demolition theory of this thread or of the WTC on September 11, 2001 CAUSED by terrorist aircraft crashing into the buildings.

Yeah, until that dastardly drunk, Santa Claus, fell out of his sleigh and hit it. And then the Magickal Jet Fuel™ AND the Easter Bunny throwing eggs at it. I don't know how anyone could have expected it to survive all that.

Liberty is not a means to a higher political end. It is itself the highest political end.
Lord Acton

My GOD man ... you didn't see the initial explosions based on the impact of the jet aircraft? Every floor (above) was cut off from support systems as the fire ravaged.

Both the FEMA and NIST reports indicate the majority of the jet fuel was spent in the fireballs, external to the building, and the rest was consumed in the first few minutes. The fires were office fires, no better, no worse.

People were mostly in the windows due to SMOKE, as they couldn't breathe inside the building, and there probably WERE some parts of the aircraft that were on fire along with the office equipment.

Not hot enough to weaken steel, but hot enough to burn people and cause them distress.

You didn't see the hundreds of people leaping to their deaths because of the fires caused by the aircraft?

As I said, the fires were there, but they weren't hot enough to melt or weaken steel. Besides the temperature not being hot enough, the heat was absorbed by the building itself, wicking the majority of the heat into the rest of the building, away from the fire.

BTW, did you have an opportunity to see the REAL seismic reports from Columbia university? Where are the explosions?

BFD? YOU'RE the one claiming the steel was weakened by fire, which is not true. If it were possible, then the North tower would have fallen down back in 1975, where the fires raged for over 3 hours.

Horizontal cutting charges more than likely wouldn't have registered. You said yourself that the seismic data only showed the final stages of the collapse.

Thank you. I knew you would finally ADMIT that the air crashes were the initial trigger mechanism for and about the collapse..... I feel vindicated now.

But what you hide in your post is the fact that the jet aircraft struck into the central core, cutting off ALL capability of fire control to the upper floors besides the 6 floors (of each building) initially ignited by fire. Shame on you, pal.

NONO ... NO... those graphs show several seismic locations around the NYC area collaborating the initial crash with time and the later collapse.

According to the science of KooKology, it's those twisting horizontal forces that caused the top to reach the ground at the same time as those lower levels, sort of like a wormhole or something.

You've already explained it buck, you said that the data only shows the last few floors hitting. That IS what you said, isn't it?

I didn't say it didn't fall........I said it didn't ACCELERATE as you and AGAviator were postulating. LOL

Well YEAH, it was the initial LURE, getting all the network cameras focused on the WTC towers, then POOF, down they go once every station is broadcasting it live.

The COLLAPSE was the MAIN ATTRACTION, and IF they hadn't collapsed, not only would there be investigations and LOTS of time to examine evidence, but it wouldn't have had the same psychological impact.

But all three towers collapsed (with acceleration) that day. All photographic material suggests the three towers fell with increasing velocity (acceleration).