World Trade Center 7 Explosion and Controlled Collaspe Caught on Tape.

a reply to: jaffo

The temperature at which steel loses 80% of its structural integrity is a fact.

And again, there is no proof for your claim. The steel they evaluated showed no signs of such a stress.

www.abovetopsecret.com...

originally posted by: PublicOpinion
a reply to: jaffo

The temperature at which steel loses 80% of its structural integrity is a fact.

And again, there is no proof for your claim. The steel they evaluated showed no signs of such a stress.

www.abovetopsecret.com...

There is not enough facepalm in the World for people like you. Sorry. You're wrong. Science shows plainly that you are wrong. Reality shows plainly that you are wrong. Seismographs from that day show plainly that you are wrong. Again: You are wrong and have been proven so.

They pulled down building 6 with just a few cables. The whole thing just caved in with very little resistance, and parts of the building probably experienced freefall.

originally posted by: PublicOpinion
a reply to: jaffo

The temperature at which steel loses 80% of its structural integrity is a fact.

And again, there is no proof for your claim. The steel they evaluated showed no signs of such a stress.

www.abovetopsecret.com...

The full section of the NIST report that your quotemine came from.

6.3.2 Spandrel Plates Exposed to Severe Fire Conditions
Table 6–2 displays information about the four locations of sample removal for the spandrel material. The samples were removed from the bottom portion of spandrel plates located at window openings where severe fire exposure conditions were observed prior to the collapse of WTC 1 (i.e., if external flaming was observed on the 97th floor, then the sample was removed from the bottom portion of the 98th floor spandrel). The minimum duration of exposure ranged from 16 min to 32 min. As reported in Sec. 6.2, visual observations for mud cracking of the paint were either negative or inconclusive (as paint was not available for inspection). The samples had a plate thickness of 0.375 in., were relatively undeformed, and had specified minimum yield strengths of 36, 42, and 50 ksi.
In comparing microstructures from both the “exposed” and “representative” samples of equivalent strength spandrel material, the following microstructural features were observed to be similar for both cases:
• Ferrite grain size and pearlite distribution (Fig. 6–9a) • Absence of a decarburization zone near the surface of the plate (Fig. 6–9a) • Limited decoration of the ferrite grain boundaries with carbides (Fig. 6–9b) • Similar appearance of pearlite (typically distinct lamella observed) • Thin, non-uniform, cracked oxide scales (Fig. 6–9a)
Again, these features were observed on all samples regardless of exposure history or specified minimum Fy. As reported in NIST NCSTAR 1-3E (2005), a 42 ksi spandrel plate was isothermally exposed at temperatures ranging from 200 °C to 625 °C for up to 2 h. Figure 6–10 shows the change in microstructure that occurred with time for the samples exposed to 625 °C; below this temperature, no apparent change to the microstructure was observed via light optical microscopy. After only 15 min of exposure at 625 °C, the pearlite showed signs of spheroidization. As this feature was not observed in any of the four spandrel materials evaluated, it was believed that the spandrels were not exposed to this temperature or that if they were, it was for significantly less time than 15 min.


In addition to the microstructural results, the hardness evaluation suggested that there was no deterioration of the mechanical properties of the materials as a result of exposure to pre-collapse fires (Table 6–2).


Based upon these results, it was concluded that none of the four portions of spandrel material visually observed in severe pre-collapse fire exposure experienced temperatures severe enough to alter the microstructure or mechanical properties of the plates when compared to samples of similar Fy that did not experience fire conditions. Further, a dense and continuous oxide scale was not observed on these samples from exposure to post-fabrication elevated temperatures. As shown in Fig. 6–9a, the oxide scale was non-uniform and relatively porous; thus, it was most likely a result of environment degradation subsequent to the collapse of the buildings and not a result of exposure to elevated temperatures. These conclusions agree with the findings of Sec. 6.2.
224 NIST NCSTAR 1-3C , WTC Investigation
The lack of high temperature exposure evidence for the fire exposed spandrels may be related to the possible temperature experienced and the duration of the exposure. Tide (1998) reviewed fire research on the exposure of structural steel to fire conditions and summarized the following points that should be considered when evaluating possible temperature excursions experienced by steel structures:
• The steel temperature is significantly reduced as the distance from the center of the fire increases. • Ventilation of a fire compartment greatly reduces the temperature of steel at distances away from
the center of the fire.
• The temperature of fire-protected steel in the vicinity of the fire is significantly less than unprotected steel at the same location.
Consideration of these points may lead to a possible explanation for a lack of microstructural change.
The longest duration of exposure evaluated was for panel S-10, which was exposed for just over 30 min (this was the longest exposure time for the recovered perimeter panels [Appendix E]). However, after 15 min of exposure to 625 °C, the 42 ksi spandrel exhibited spheroidization of the pearlite. It would be expected that the 50 ksi plate would behave similarly. If the exposure temperatures were somewhat below this, then kinetically, it may not have been possible to produce a microstructural change within this time frame. Additionally, the windows were consistently breaking out as the fire advanced, allowing for ventilation of the fire compartment to occur. Thus, the temperatures of the spandrel steel may not have been as high as if there was no ventilation of the floors. Finally, a majority of the perimeter panels that burned out were most likely undamaged after the impact. The sprayed fire-resistive material applied to the columns and spandrels may well have been intact and would have provided some protection from the high temperatures of the fire. Thus, it was plausible to conclude that the maximum temperature the steel may have attained was below that which would have allowed for microstructural changes, despite severe fire exposure observed photographically.

Do you need me to explain what it says to you ?

a reply to: ForteanOrg

Here is a 21-story steel frame building that collapsed in Mexico City.

Totally Collapsed 21-Story Steel Frame Office Building

911research.wtc7.net...

When it comes to steel frame buildings, you can can pull them down with nothing more than steel cables once the steel structures have been pre-weakened. Check out time line 1:48.

www.youtube.com...

In the case of WTC 1 and WTC 2, their structures were pre-weakened from the aircraft impacts. In the case of WTC 7, it was pre-weakened when debris from WTC 1 punched out a 20-story hole on its south facade. In other words, the impact hole that WTC 7 suffered was larger than those of WTC 1 and WTC 2.

a reply to: PublicOpinion

And again, there is no proof for your claim. The steel they evaluated showed no signs of such a stress.

At temperatures recorded within the WTC buildings, steel would have lost much of its strength.

Fire damage assessment of hot rolled structural steelwork

All materials weaken with increasing temperature and steel is no exception. Strength loss for steel is generally accepted to begin at about 300°C and increases rapidly after 400°C. By 550°C steel retains approximately 60% of its room temperature yield strength, and 45% of its stiffness.

At high temperatures, steel is also subjected to significant thermal elongation, which may lead to adverse impacts, especially if it is restrained. It follows therefore that one would expect that structural steelwork which has been subjected to high temperatures would exhibit signs of this in the form of distortion and buckling.

www.steelconstruction.info...

You will have noticed where the article indicated that steel exposed to high temperatures would exhibit signs of distortion and buckling. Now, let's take a look here.

WTC Pre-Collapse Bowing Debunks 9/11 "Controlled Demolition" Theory

"The NYPD aviation unit reported critical information about the impending collapse of the buildings." They could see that the exterior steel beams of the buildings were bowing. You can see the inward bowing of the steel columns in pictures of both WTC 2,

"According to Shyam Sunder, the concave bowing of the steel was seen on the sides of the towersopposite where the planes hit them. At 10:06 a.m. that morning, an officer in a police helicopter reported that ``it's not going to take long before the north tower comes down.'' This was 20 minutes before it collapsed. In another radio transmission at 10:21 a.m., the officer said he saw buckling in the north tower's southern face, Shyam Sunder said."

www.representativepress.org...

Upon examination.

The structural engineering community rejects the controlled-demolition conspiracy theory

The structural engineering community rejects the controlled-demolition conspiracy theory. Its consensus is that the collapse of the World Trade Center buildings was a fire-induced, gravity-driven collapse, an explanation that does not involve the use of explosives

Thomas Eagar, a professor of materials science and engineering at the Massachusetts Institute of Technology, also dismissed the controlled-demolition conspiracy theory. Eagar remarked, "These people (in the 9/11 truth movement) use the 'reverse scientific method.' They determine what happened, throw out all the data that doesn't fit their conclusion, and then hail their findings as the only possible conclusion."

www.civil.northwestern.edu..." target="_blank" class="postlink" rel="nofollow">web.archive.org...://www.civil.northwestern.edu/people/bazant/PDFs/Papers/466.pdf

9/11 Debunked: World Trade Center's Collapse Explained

www.youtube.com...

a reply to: PublicOpinion

As there is not a single shred of evidence for weakened steel (due to pre-collapse fires), we may also try to be firm believers in the flying spaghetti monster either. Or in Alien Rays for that matter, I see no difference nor proof for any of those theories.

That''s false. Photos have been released showing bowed steel beams without cracking. Other than observed bowing of WTC 1, WTC 2 and WTC 7 just before their collapse, this is further evidence that fire weakened the steel beams.

i0.wp.com...

originally posted by: jaffo
So because something you have never seen before did not look the way you think it should have, you don't believe what happened is what actually happened.

Of course "what happened is what happened ..

Ok then. Although really I think you're just having yourself a jolly old time trolling a board with this alien ray garbage.

Actually, it is what happened. One more time, this is roughly how it went: our former allies found out that we were breaking our agreements with them. We had reverse engineered some stuff we weren't supposed to have (yet). They told us to stop it. We said we would, but did not. Hence they warned us what they would do: they would bring down the WTC complex and would punch a hole in the Pentagon. They even said when, and frankly they did not give a dang if "humanity" found out or not. They do as they please here and we'd better stay out of their way, that's their message.

Alien ray. Told ya.

Like you can not convince me by repeating a nonsensical story - I don't expect you to be convinced by mine.

Let's agree to disagree.

a reply to: Salander

Large pieces blown out and away means that something besides gravity was at play. Only explosive devices can move such pieces like that. Fires and gravity cannot.

That is false, as evident by the fact that steel columns can bee seen standing within a huge bomb crater after a huge bomb was detonated beneath WTC 1 in 1993.

upload.wikimedia.org...

We can also take a look here where blast waves from explosions flow around steel beams.

www.fototime.com...

www.jadaliyya.com...

www.indybay.org...

As further proof that demolition explosives were not used to demolish the WTC buildings can be found on the seismic charts. As you can see in these charts, there were no signals generated from explosives. They recorded aircraft impacts and collapse of the WTC buildings, but no signals generated from explosives just prior to the collapse of the WTC buildings.

dickatlee.com...

dickatlee.com...

Demolition experts who were operating the seismic monitors on another project have stated that they heard no demolition explosions at ground zero, which was evident in the videos that I posted yesterday.

a reply to: ForteanOrg

Actually, it is what happened. One more time, this is roughly how it went: our former allies found out that we were breaking our agreements with them. We had reverse engineered some stuff we weren't supposed to have (yet). They told us to stop it. We said we would, but did not. Hence they warned us what they would do: they would bring down the WTC complex and would punch a hole in the Pentagon. They even said when, and frankly they did not give a dang if "humanity" found out or not. They do as they please here and we'd better stay out of their way, that's their message.

I got lost at what you are implying, but it was our allies that warned the United States that Osama bin Laden and al-Qaeda would use aircraft to attack America.

WARNINGS THAT THE DANGER WOULD COME FROM THE AIR

BRITAIN, WARNING #1: Al-Qaeda is planning to use aircraft in "unconventional ways", "possibly as flying bombs"

the British intelligence agency, gives a secret report to liaison staff at the US embassy in London. The reports states that al-Qaeda has plans to use "commercial aircraft" in "unconventional ways", "possibly as flying bombs." [Sunday Times, 6/9/02]

BRITAIN, WARNING #3: An Al-Qaeda attack will involve multiple hijackings

Early August 2001 ©: Britain gives the US another warning about an al-Qaeda attack. The previous British warning (see July 16, 2001) was vague as to method, but this warning specifies multiple airplane hijackings. This warning is included in Bush's briefing on August 6. [Sunday Herald, 5/19/02]

CAYMAN ISLANDS, WARNING #2: Three al-Qaeda agents are part of a plot "organizing a major terrorist act against the US via an airline or airlines"

August 29, 2001: Three men from either Pakistan or Afghanistan living in the Cayman Islands are briefly arrested in June 2001 for discussing hijacking attacks in New York City (see June 4, 2001). On this day, a Cayman Islands radio station receives an unsigned letter claiming these same three men are agents of bin Laden. The anonymous author warns that they "are organizing a major terrorist act against the US via an airline or airlines." The letter is forwarded to a Cayman government official but no action is taken until after 9/11 and it isn't known when the US is informed. Many criminals and/or businesses use the Cayman Islands as a safe, no tax, no questions asked haven to keep their money. The author of the letter meets with the FBI shortly after 9/11, and claims his information was a "premonition of sorts." The three men are later arrested. Its unclear what has happened to them since their arrest. [Miami Herald, 9/20/01, Los Angeles Times, 9/20/01, MSNBC, 9/23/01] FTW

EGYPT, WARNING #1: An undercover agent learns 20 al-Qaeda agents are in the US, four have received flight training

Late July 2001 (D): CBS later has a brief mention in a long story on another topic: "Just days after Atta return[s] to the US from Spain, Egyptian intelligence in Cairo says it received a report from one of its operatives in Afghanistan that 20 al-Qaeda members had slipped into the US and four of them had received flight training on Cessnas. To the Egyptians, pilots of small planes didn't sound terribly alarming, but they [pass] on the message to the CIA anyway, fully expecting Washington to request information. The request never [comes]." [CBS, 10/9/02] This appears to be one of several accurate Egyptian warnings based on informants (see June 13, 2001 and August 30, 2001). Could Egypt have known the names of some or all of the hijackers? Given FBI agent Ken Williams' memo about flight schools a short time before (see July 10, 2001), shouldn't the US have investigated this closely instead of completely ignoring it?

GERMANY: Terrorists will use airplanes as weapons to attack "American and Israeli symbols"

June 2001: German intelligence warns the CIA, Britain's MI6, and Israel's Mossad that Middle Eastern terrorists are planning to hijack commercial aircraft to use as weapons to attack "American and Israeli symbols, which stand out." A later article quotes unnamed German intelligence sources who state the information was coming from Echelon surveillance technology, and that British intelligence had access to the same warnings. However, there were other informational sources, including specific information and hints given to, but not reported by, Western and Near Eastern news media six months before 9/11. [Frankfurter Allgemeine Zeitung, 9/11/01, Washington Post, 9/14/01, Fox News, 5/17/02] FTW

ITALY: Muslims warn of an attack on the US and Britain using hijacked airplanes as weapons

September 7, 2001: Father Jean-Marie Benjamin is told at a wedding in Todi, Italy of a plot to attack the US and Britain using hijacked airplanes as weapons. He isn't told time or place specifics. He immediately passes what he knows to a judge and several politicians. He states: "Although I am friendly with many Muslims, I wondered why they were telling me, specifically. I felt it my duty to inform the Italian government." Benjamin has been called "one of the West's most knowledgeable experts on the Muslim world." Two days after 9/11, he meets with the Italian Foreign Minister on this topic. He says he learned the attack on Britain failed at the last minute. [Zenit, 9/16/01] He has not revealed who told him this information, but could it have been a member of the al-Qaeda cell in Milan (see August 12, 2000 and January 24, 2001), which appears to have helped with the 9/11 attacks?

JORDAN: A major attack using aircraft is planned inside the US

Late summer 2001: Jordanian intelligence (the GID) makes a communications intercept deemed so important that King Abdullah's men relay it to Washington, probably through the CIA station in Amman. To make doubly sure the message gets through it is passed through an Arab intermediary to a German intelligence agent. The message states that a major attack, code named The Big Wedding, is planned inside the US and that aircraft will be used. "When it became clear that the information was embarrassing to Bush Administration officials and congressmen who at first denied that there had been any such warnings before September 11, senior Jordanian officials backed away from their earlier confirmations." Christian Science Monitor calls the story "confidently authenticated" even though Jordan has backed away from it. [International Herald Tribune, 5/21/02, Christian Science Monitor, 5/23/02] FTW

RUSSIA: Russian intelligence clearly warns the US several times that 25 or so terrorists, including suicide pilots, will attack the US, targeting "important buildings like the Pentagon"

August 2001 (D): Russian President Putin warns the US that suicide pilots are training for attacks on US targets. [Fox News, 5/17/02] The head of Russian intelligence also later states, "We had clearly warned them" on several occasions, but they "did not pay the necessary attention." [Agence France-Presse, 9/16/01] A Russian newspaper on September 12, 2001 claims that "Russian Intelligence agents know the organizers and executors of these terrorist attacks. More than that, Moscow warned Washington about preparation to these actions a couple of weeks before they happened." Interestingly, the article claims that at least two of the terrorists were Muslim radicals from Uzbekistan. [Izvestia, 9/12/01, (the story currently on the Izvestia web site has been edited to del

originally posted by: PublicOpinion
a reply to: Salander

As there is not a single shred of evidence for weakened steel (due to pre-collapse fires), we may also try to be firm believers in the flying spaghetti monster either. Or in Alien Rays for that matter, I see no difference nor proof for any of those theories.

Exactly my point

a reply to: ForteanOrg

A petroleum based fire. That's what black smoke means to me as someone who has attended several firefighting schools.

a reply to: waypastvne
a reply to: skyeagle409

steel would have lost much of its strength.

We don't need to discuss pictures if we could examine the Nist-report instead, do we? It's pretty easy, let me break all this gibberish down for you:
Nist didn't find evidence for weakened core columns (due to fire) and explained why they didn't bother. To be more precise, they stated the following points have to be considered when discussing said hardness evaluation (from the part waypastvne just added here):

- greater distance to the fire reduced the temperatures significantly
- ventilation reduced the temperature greatly
- fire-protection reduced the temperature significantly

That's a beautiful bummer, innit? Plausible deniability at it's finest - they imagined the fictional proof to be somewhere beyond their grasp and thus concluded those actually examined examples have to be considered irrelevant at best. Said spandrel material in fact contradicted their fiery theory the same way all the other microstructural results did.
Awesome indeed but the lack of evidence is far from beeing proof for any theory. This is just another dogma one could choose to believe in or choose to be called heretic if one dares to keep up with certain standarts, previously known as the 'Wonder of Science'. Yes I can (see the Spanish Inquisition at work to keep their flock in shape).

Thank you for consideration and have a nice day!

a reply to: PublicOpinion

Nist didn't find evidence for weakened core columns (due to fire)

That is incorrect and the photos proved beyond a shadow of a doubt and confirmed when eyewitnesses reported that WTC 1, WTC 2 and WTC 7 began to buckle just prior to their collapse, which is a firm indication that fire was slowly weakening their steel structures.

Structural buckling proved that fire, not explosives, was responsible for the collapse of WTC 1, WTC 2, and WTC 7

"According to Shyam Sunder, the concave bowing of the steel was seen on the sides of the towersopposite where the planes hit them. At 10:06 a.m. that morning, an officer in a police helicopter reported that ``it's not going to take long before the north tower comes down.'' This was 20 minutes before it collapsed. In another radio transmission at 10:21 a.m., the officer said he saw buckling in the north tower's southern face, Shyam Sunder said."

Explosives don't slowly buckle steel columns over several minutes.

www.representativepress.org...

i662.photobucket.com...


Why Did the World Trade Center Collapse? Science, Engineering, and Speculation

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.

www.tms.org...

It was a demolition of some kind, no it didnt fall due to fire because fire doesnt make buildings freefall. Pretty much a no brainer.

a reply to: FormOfTheLord

It was a demolition of some kind, no it didnt fall due to fire because fire doesnt make buildings freefall. Pretty much a no brainer

Apparently, demolition teams in the area working on other projects, stated that they heard no demolition explosives, which is evident in the videos I posted where no explosions were heard just prior to the collapse of WTC 1, WTC 2, and WTC 7. I also posted the seismic charts and I invite you to show us where explosions were detected on those charts and I expect a reply from you afterward.

There was no way to plant explosives in any of the WTC buildings and not attract a lot of attention. To prepare such buildings for explosive demolition would generate tons of waste material in order to gain access to the steel structures and in the process create clouds of dust and lots of noise and do so for many months, which would not have been tolerated in occupied buildings.

As noted earlier, a huge bomb failed to bring down WTC 1 in 1993 and its steel columns were still sitting within the huge bomb crater. Those who think that explosives brought down the WTC buildings do not understand the demolition preparation process.

Explosives alone cannot bring down steel frame buildings. Have you ever wondered why many buildings in Iraq remained standing despite receiving multiple strikes by JDAM bombs and cruise missiles? Think about it.

I might add that none of the WTC buildings fell at freefall speed, which was evident by the fact that dust plumes and debris can be seen outpacing the collapse themselves.

This photo proves that the WTC building is not falling at freefall speed and note the dust plumes and debris outpacing the collapse of the building.

contrailscience.com...


This video proves no freefall collapse

www.youtube.com...

originally posted by: skyeagle409
a reply to: PublicOpinionThat is incorrect and the photos proved beyond a shadow of a doubt and confirmed when eyewitnesses reported that WTC 1, WTC 2 and WTC 7 began to buckle just prior to their collapse, which is a firm indication that fire was slowly weakening their steel structures.

Or that the Alien Ray did its nefarious work.

Alien Ray. Told ya.

originally posted by: skyeagle409Explosives alone cannot bring down steel frame buildings. Have you ever wondered why many buildings in Iraq remained standing despite receiving multiple strikes by JDAM bombs and cruise missiles? Think about it.

I do.

If you were right, we'd have a new "Wunderwaffe". We could simply use old airplanes, fill them up with kerosine, fly them into any high-rise building and not only would that high-rise building buckle and come down at free fall speed, but as a bonus a totally different type of high-rise building, standing near it, would also collapse at free fall speed.

Can't you see how ridiculous that is?

a reply to: skyeagle409

Behold a REAL intense fire, which burned for 5 hours. Look at the intensity of the fires.



We can agree, I hope, that the fires in WTC 1,2 and 7 aren't even close to this inferno. If fires like these can rage for 5 hours, but the building remains intact - why did that building not collapse?

There are many more examples of high-rise steel buildings that caught (intensely burning) fires. Some of them show very, very clear evidence of very, very serious detoriation. None of them collapsed.

Heck, even WTC1 itself survived a serious fire in 1975. It started on the 11th floor and spread to six other floors, burning for three hours. Firefighters reported a "very intense, very hot fire". Nothing happened. Not a beam was weakened. Not even a single truss needed to be replaced.

The kerosine from the planes that hit WTC1 and WTC2 burned out in roughly ten minutes. Yes, there was structural damage, but since both towers were still standing roughly an hour after impact and there was neglible wind, the Towers should have remained standing. The status quo of a building is just that and if you don't change something, the building just sits there.

The story of 'weakening beams by fire' is clearly nonsense as proven by many many burning bujldings and the 1975 WTC1 fires. If you believe that a kerosine fire that burns for less than 10 minutes weakens steel - ask yourself why the buildings remained standing after these fires burned out. Assuming the beams were weakened, they would be weakest during the time the kerosine still burned - why then did the towers not collapse at that moment? Why did they hesitate (and cooled down, regaining their strenght)? And how come that the entire construction came down in the blink of an eye - regardless that 90 floors below the impact zone hadn't even been damaged at all? Nothing changed, no new plane flew into the building, the trusses weren't broken - the fires were actually mostly out.

Alien Ray. Told ya.

The only way the official report of the trade tower collapse could be taken seriously is if the core structural beams(not the outside shell) in the trade towers were made of Delicious biscuity pastry(with a mouth watering dark chocolate center). Held together with rum and raisin fudge fasteners, that's why it collapsed on its own footprint at free fall speed....