WTC Collapses

The collapse of WTC 7

Nods. leopold99 made the claim back in post 430. This is how they get laymen, you see. Some people come up with a bunch of fallacy rich claims and laymen simply can't tell the truth for the chaff. We thus get bogged down in such things. Anyway, thanks for clearing that up.

 

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Levels 7 through 14 of WTC7 were closer to the bottom of the building than the top so the majority of the mass was coming down on the rest. In the case of the north tower that I am talking about only 16% by volume would be coming down on 81% by volume and the differences in mass should be greater than that. I think the top would either stop or fall off the side within double its own height. I have no idea how the energy required to crush one level is computed though.

The south tower is a very different case because we already have videos of the top tilted. Richard Gage said it was 22 degrees but I have seen other sources give smaller numbers. My guesstimates from the pictures I have seen would make at least 15 degrees. It should have crushed one side of the lower portion more than the other causing the tilt to increase until the center of mass was beyond the outer edge of the building resulting in it falling down the side.

psik

 

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I kind of doubt that 400,000 tons could do a good job of whip cracking. The graph in NCSTAR1 has the oscillation damping out in four minutes. Each cycle looks like it took about 12 seconds.

psik

 

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No in light if the many facts that is an incorrect assertion.

You want to explain that one? There is evidence of bowing minutes before the collapse of WTC1 and seconds before that of WTC2.

Well lets look at them.

Does not point to a controlled demolition. The fires alone were hot enough to keep metals with a low melting point in this state for a while.

So they did not reach the same temperatures as WTC1+2. That does not point to a controlled demolition. Remember that steel was found buckled in WTC5. No jet fuel was needed to get that fire going.

The microspheres can be caused by things other than thermite.

With the floors buckling leading up to the collapse it wasn’t sudden.

Could the remainder of the plane?

Irrelevant. It was enough to get a roaring office fire going.

You are again referring to the tests on panels. Very few of them came from the impact areas.

There is footage and photos of steel which was clearly exposed to very high temperatures.

Much more was inspected.

WTC was not a target, no one died, those at the scene thought it would collapse. Nothing suspicious here.

Even if it was in freefall once the collapse began, and I’m not convinced that it was, that doesn’t confirm a controlled demolition.

Doesn’t mean it was indestructible.

Compressed air

Incorrect. Steel framed buildings have collapsed due to fire. No skyscraper has collapsed though. No 767 has ever slammed into a skyscraper at 500mph before either.

Although I doubt that there was ‘almost no column damage’ and that you could possibly know that, what matters is fireproofing being dislodged and the jet fuel getting the fire going on those floors.

Quantity is not quality. Listing many incorrect or unconvincing claims doesn't make the case more credible.

 

Could you clarify what was 400,000 tons? The combination of steel and concrete per tower? I personally believe that Jerry Russell's calculation of 90,000 tons of concrete per tower is the one with the best calcuations- that would leave 310,000 tons of steel.. it seems a bit much.

 

Shaman,

Do you know what strain hardening is?

In spite of tens of videos taken of the towers before the collapses, there is no video evidence of perimeter column bowing for minutes before the collapses occurred. So it sounds like you are just taking somebody's word for it. I am sure you realize that if the outer core columns were cut that this mechanism would cause extreme bowing in the perimeter columns. The only video we have of perimeter column bowing is just before complete collapse ensues.

Please provide a mechanism other than incendiaries or a blast furnace to melt steel. A blast furnace requires a massive infusion of oxygen in a controlled chamber. Please explain how you think this could have occurred in the rubble pile. How did the metal become molten to begin with? Are you trying to say the molten metal in the rubble wasn't steel or iron?

What kind of inspection was done on 99.5% of the tower steel before it was recycled? Just looking at it doesn't tell us much. Were there any tests done? The answer is a big no.

Only the fuselage and engines could have made it to the core. The fuselage was 16.5 feet in diameter and most of that was thin walled aluminum so how much damage could the fuselage have done to the core? On top of that it would have been slowed tremendously by the wings being ripped off and shredded as well as by going through at least one reinforced concrete floor itself.

It would be amazing if you could simply tell from photos what temperatures the steel experienced. Please tell us how that is done.

Why wasn't steel from the fire affected areas in the towers saved for testing and a real forensic analysis? We really would like to know.

WTC 7 would have been the first skyscraper in history to collapse due to fire, if we are to believe the present government story on it ,and yet none of it's steel was saved for forensic analysis. Nothing suspicious here? Please!! Just because nobody was killed doesn't mean you don't do a proper investigation into an unprecedented collapse.

Please explain how WTC 7 could have been in freefall for 2.25 seconds, which even NIST has now admitted to, in a natural collapse situation.

Skyscrapers are built with a large amount of redundancy for good reason. The tower columns only had about 25% of their load capacity used. In order for a continuous collapse to occur an impulsive load must be applied to overcome the factor of safety. This requires deceleration. Studies of the fall of the upper block of the North tower show no such deceleration. The only other mechanism which could cause the continued collapse is some form of controlled demolition.

Most would find it hard to believe that compressed air would be exiting the towers 20 stories or 250 feet below the collapse zone in a focused way. Please explain the mechanism for this if you don't believe it was caused by squibs.

John Skilling, the chief engineer on the tower design, said if the towers were hit by a large airliner it would cause a big fire but that the building structure would still be there. They did a study on it and a white paper dated February 1964 discusses it. I have already explained why the aircraft could only do limited damage by volume alone. The core columns were 11 to 21 feet apart.

Read the NIST report to see how little impact damage there was on the 98th floor, where the collapse initiated in the North Tower. Read Kevin Fenton's short paper on it at http://www.journalof911studies.com/volume/2008/FentonWTCInitiationFloors.pdf

The arguments made here showing controlled demolition explains what we observed in the destruction of the towers and WTC 7 would be viewed by most as being science based. You haven't made any scientific objections to them and you need to if you want to impugn their quality.

 

Kevin Ryan and his former employer Underwriter Laboratories, Round 5


This post is in response to the 4th part of shaman_'s post 542 in this thread.

There is lots of evidence for the flyover theory as http://www.thepentacon.com/ makes clear.

Szamboti and others have made it clear that the planes did little damage and the fires did less. There is also only evidence of a tiny bit of fireproofing removal pre collapse, where the steel beams themselves were sheared where the plane crashed into the building.

Only at the entrance, where some steel beams were sheared. He never claimed that -all- of the fireproofing hadn't been removed, only most of it.

Kevin Ryan's "Standard For Deception" presentation, for one:
**************
5. Some floors began to sag?

Step five in NIST's collapse theory is that floors began to sag. The idea that fires could have caused floors to sag is not unreasonable, since it has been observed in fire tests and in cases of severe fires in steel-framed buildings, such as the One Meridian Plaza fire.

What is not reasonable is the degree of sagging NIST used in its computer models compared with the amounts its physical tests showed. Whereas the 35-foot floor model sagged only a few inches in the middle after two hours in a high-temperature furnace, NIST's computer model showed a sagging of 54 inches.

6. How did floors pull columns inward causing them to buckle?

Ryan dubs NIST's use of a computer model to support its theory of floor-sag-induced inward bowing of perimeter columns the "triple double bare steel computer result." He is referring to the fact that NIST's computer model doubled the height of the unsupported wall sections, doubled the temperatures, doubled the duration of the stress, and ignored the effect of insulation.
**************

The Windsor tower in Madrid had some important differences, as 9/11 Research makes clear.

The McCormick steel structure was a warehouse, not a highrise. Again, 9/11 Research points out the many differences.

The official story certainly has a lot of examples. 9/11 Research apparently doesn't cover those last 2, but I think we should deal with the first 2 first...

It's nothing of the sort. Steven Jones dealt with that issue over at prisonplanet.com.

Yes, his letter made mention of melting steel. Let's get the context of that mention:
*****************
There continues to be a number of "experts" making public claims about how the WTC buildings fell. One such person, Dr. Hyman Brown from the WTC construction crew, claims that the buildings collapsed due to fires at 2000F melting the steel (1). He states "What caused the building to collapse is the airplane fuel . . . burning at 2,000 degrees Fahrenheit. The steel in that five-floor area melts." Additionally, the newspaper that quotes him says "Just-released preliminary findings from a National Institute of Standards and Technology study of the World Trade Center collapse support Brown's theory."

We know that the steel components were certified to ASTM E119. The time temperature curves for this standard require the samples to be exposed to temperatures around 2000F for several hours. And as we all agree, the steel applied met those specifications. Additionally, I think we can all agree that even un-fireproofed steel will not melt until reaching red-hot temperatures of nearly 3000F (2). Why Dr. Brown would imply that 2000F would melt the high-grade steel used in those buildings makes no sense at all.
*****************

As to his statement regarding how hot the fires got, he was relying on NIST's interim report. Again from his letter:
*****
The results of your recently published metallurgical tests seem to clear things up (3), and support your team's August 2003 update as detailed by the Associated Press (4), in which you were ready to "rule out weak steel as a contributing factor in the collapse". The evaluation of paint deformation and spheroidization seem very straightforward, and you noted that the samples available were adequate for the investigation. Your comments suggest that the steel was probably exposed to temperatures of only about 500F (250C), which is what one might expect from a thermodynamic analysis of the situation.
*****

Laugh

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. So why did you choose that nick ten years ago? Do you have native american roots, an admiration for shamans or all/none of the above

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?

 

In that particular instance I was referring to the entire building swaying back and forth. That is going to include plumbing and glass and light fixtures etc., etc.

I emphasize steel and concrete because that is what held the building up. Until someone supplies numbers for every level of the towers including the basements I am not going to believe anything. There had to be A LOT of concrete in the foundation and basements of those towers. I would be somewhat surprised if it wasn't more than all of the floor slabs combined.

psik

 

He says there were outriggers to support the building over a hole. This is not correct.

What he apparently is thinking of is that WTC 7 was built partly over an electrical substation and the north side of the building had deep trusses spanning from the central core to large exterior columns for the first few floors to bridge over the substation which was a couple of stories tall. This had nothing to do with the collapse of the building or why it went down so smoothly.

 

Nope.

You are correct that I am going from photographic evidence and have trusted that the times on those photos are correct. However there is testimony to back this up and I have read this at many sources.

Here is a good summary. http://www.representativepress.org/BowingDebunksExplosives.html


There may be video though but I am at work and can’t search.

Please provide reliable evidence of melted steel.

I think it is unlikely. How do you know that it was steel or iron?

No I didn’t say 99.5% was inspected. Qualified people spent weeks going over thousands of tons of steel though.

What they observed was consistent with the official story.

It was still enough to damage some columns, knock off some fireproofing.

The analysis of the steel was done by people such as structural engineer Abolhassan Astaneh-Asl. They did not use photos to reach their conclusions. There are however photos that show steel twisted and softened by the fire. That is what I am referring to. This supports estimated temperatures of 1000C.

I admit that is disappointing. It’s as if they collected the best looking panels – which were the least heat affected. However that is just one part of the NIST investigation and the evidence for temperatures of 1000C does not completely rest on the panel samples. There was plenty of steel found which was clearly softened by the fire and there is other evidence of much higher temperatures.

Everything that happens for the first time is suspicious? Steel framed buildings have collapsed due to fire. WTC7 was just a taller steel framed building. Had nothing else happened that day other than WTC7 then perhaps the ending would have been different. However a lot happened that day. It isn’t very common for skyscrapers to collapse and collide with other buildings as happened to WTC7. It isn’t very common for that many firefighters to be killed in one incident. Lack of water ect.

To those who were actually there it was not suspicious at all. They could see the building looked dangerous and pulled out. They were right to do so.

One of the bottom floors completely gave way and gravity did the rest.

This becomes irrelevant when enough columns have been damaged and weakened by fire.

In a focused way? It is just air trying to escape and coming out some windows. A large part of the building was air. It was pushed downwards during collapse. Think of a syringe. This is supported by testimony from firemen who were in the stairs when the collapse started. They felt a strong wind when they heard the collapsing floors.

Squibs would be exploding out faster than that and would be used to initiate the collapse. The few pointed out by truthers are seen as the collapse is already in full effect. By that stage there is already a lot of force coming downwards and no need for any squibs.

Leslie Robertson claims that the jet fuel was not taken into account and they were not estimating that the plane would be flying at full speed.

Reading now.

For the most part your claims are not based on science so neither are my rebuttals. They are merely observations as are mine.

 

you are now suggesting that a demolition was possible by installing demolition devices on a single floor. i think we have made some progress.

I was under the impression that skyscrapers are held up by the vertical columns, not the floors.

 

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more here:
http://www.fema.gov/pdf/library/fema403_apc.pdf

http://www.journalof911studies.com/articles/WTCHighTemp2.pdf

 

Good luck trying to find video of bowing perimeter columns. I have searched for quite some time and there are none. There have been others I said this to who didn't believe it and they had to come back with the same answer.

I am glad you mentioned Structural engineer Abolhassan Astaneh-Asl as he himself said he saw evidence of steel which had melted and vaporized from the towers and WTC 7. He admits it to PBS in May 2007 here http://www.pbs.org/newshour/bb/science/jan-june07/overpass_05-10.html. It is about 3/4 of the way down the article.

And here in October 2001 he tells the NY Times that a piece of steel he saw from WTC 7 had been partly vaporized.

http://query.nytimes.com/gst/fullpage.html?res=9B05E6DC123DF931A35753C1A9679C8B63

There are numerous NYC firefighters who have said there was molten steel in the rubble and are interviewed on video which is on the Internet.

There are several published observations of molten metal in the basements of all three buildings, WTC 1, 2 (”Twin Towers”) and 7. For example,

Dr. Keith Eaton toured Ground Zero and stated in The Structural Engineer, ‘They showed us many fascinating slides’ [Eaton] continued, ‘ranging from molten metal which was still red hot weeks after the event, to 4-inch thick steel plates sheared and bent in the disaster’. (Structural Engineer, September 3, 2002, p. 6; emphasis added.)

Sarah Atlas was part of New Jersey’s Task Force One Urban Search and Rescue and was one of the first on the scene at Ground Zero with her canine partner Anna. She reported in Penn Arts and Sciences, summer 2002,
‘Nobody’s going to be alive.’ Fires burned and molten steel flowed in the pile of ruins still settling beneath her feet. (Penn, 2002; emphasis added.)

Dr. Allison Geyh was one of a team of public health investigators from Johns Hopkins who visited the WTC site after 9-11. She reported in the Late Fall 2001 issue of Magazine of Johns Hopkins Public Health, “In some pockets now being uncovered they are finding molten steel.”

Thus, molten metal was repeatedly observed and formally reported in the rubble piles of the WTC Towers and WTC 7, metal that looked like molten steel. Unfortunately, it was never tested to ascertain the actual composition. Why not?

What could they have observed other than bowed and twisted metal? They didn't reconstruct anything and determine some sort of failure mode or sequence. They did no testing on the steel at Freshkills landfill and the steel was shipped off for recycling from there, except for the paltry 0.5% they saved for NIST.

Here is more for you to think about here. The North tower aircraft nose entered the tower at the 95th floor on the north side at a 10 degree downward pitch angle. The North tower bowing allegedly occurred at the 98th floor on the south side of the building. If one were to extrapolate the 10 degree angle across the 209 foot building the aircraft debris would have been concentrated at about 70 feet below the 98th floor. However, we are to believe the fireproofing was stripped off of the floor trusses of the 98th floor on the south side of the building. This does not add up.

The steel was most likely twisted by impact forces not fire. The only way to tell what temperature the steel experienced is to do tests on the spheroidization of the microstructure.

How can you tell if the steel was softened by fire? Was the hardness tested to see if was annealed? I haven't heard that. Since there is no mention of any testing done at Freshkills landfill in the NIST report it seems all they could have done was look at the steel and say yes it is all twisted and broken and looks like it was in a fire. Isn't that great? In the meantime NIST has to say most of the steel wasn't available for them to test. I think it is naive not to be suspicious of how the steel evidence was handled.

No legitimate steel framed high rise building has ever collapsed due to fire. The Chicago warehouse building isn't analogous and neither is the three story ramshackle building in Thailand that collapsed even though it had steel in it.

Why wasn't water run from fire hydrants a mile away or the nearby fireboats and the standpipe system used on WTC 7? This could have been done without entering the building.

Are you trying to say a 2.25 second freefall occurred due to a bottom floor caving out? That doesn't work mathematically.

It doesn't sound like you understood the need for impulse. I am speaking about what happens after the initiation of the collapse and what is needed to collapse succeeding floors which could carry four times the static load above them.

I am talking about 250 feet below the collapse zone. The air would not be pressurized that far away over a wide expanse of the building and these blowouts were high velocity and very focused.

Unfortunately, Leslie Robertson is contradicted by his late boss John Skilling here, who when asked in 1993 if he had considered plane crashes in his design Skilling referred to a 1964 analysis of just this issue: “Our analysis indicated the biggest problem would be the fact that all of the fuel would dump into the building. There would be a horrendous fire. A lot of people would be killed, ... the building structure would still be there.” The February 1964 white paper which discussed that analysis also said they considered a Boeing 707 or DC-8 flying at 600 MPH. The NIST report says they saw the white paper and it says the analysis considered a 600 MPH airspeed of the aircraft. So Leslie is contradicted by the actual record on both counts of the fuel and airspeed. Here is a link to the Seattle Times interview of John Skilling in 1993. http://community.seattletimes.nwsource.com/archive/?date=19930227&slug=1687698

 

Astaneh and his small team did not arrive until a few weeks after 911 and access to ground zero was restricted, I think most of his inspection were done at fresh kills and scrap yards after cleanup cutting was done. How would anyone have been able to visually distinguish between damage and cutting due to cleanup operations and any damage, melting, or cutting that might have been due to demolition devices?

A lot of the steel had already been destroyed before his small team of volunteers arrived, I also recall his complaining about being subject to a non-disclosure agreement.

 

They are probably the most idiotic members of the truth movement. You may not like the insult scott but there is no other way to describe it. If I was a truther I would still distance myself from them. They interview people who say that they saw the plane hit the pentagon, they take their own interpretations of the flight path and then conclude that a plane didn’t hit the pentagon. The witness testimony and physical evidence makes the case overwhelming but they ignore all that and cling to their own interpretations of a few people.

NISTs testing on fireproofing removal showed results which were consistent with their expectations.

You don’t even need most of it removed, just enough around the floors affected by fire.

Attacking the NIST model does not support your claim that “even without fireproofing, even the initial floor wouldn't have done more then sag a bit”

If steel framed buildings are able to collapse due to fire, then why couldn’t a fire initiated with thousands of gallons of jet fuel and a nice hole for ventilation do the same thing? Just saying a ‘skyscraper is a different type of building’ is not an answer.

Nothing in that article you keep linking to addresses my comment. You must be able to think for yourself. We have done that article to death and I still can’t get an answer out of you as to what you think it proves.

Once again “The steel on the Madrid tower did more than sag a little.” The steel supports collapsed.

How many floors above or below the fire is irrelevant when I am demonstrating to you that fire can cause steel to weaken and collapse. The roof of the McCormick Place collapsed in 30mins from a simple fire! No 767, no jet fuel. Simply saying, ‘oh but it wasn’t a high rise’ is not a response.

We have devoted about 20 posts to them and all you ever come up with insufficient responses and link to the same two pages.

You must be able to discuss things that 911research doesn't mention.

Have you actually read that article? It is appalling. They completely miss the relevance of the incident – that a gas fire caused steel to weaken and collapse.

Comments like “Jones said that the notion that steel supporting columns completely melted from fire is impossible” are feeble strawmen.

Comments like “In addition, the "pancake" collapse of the freeway did not even manage to collapse the section of road below it, whereas the collapse of the south tower pulverized over 10 floors a second.

Building 7 was not hit by anything save a small amount of debris from the towers and suffered limited fires across just eight floors. In addition, explosions were being reported by occupants within WTC 7 before the towers had even collapsed.
The columns supporting the freeway were not pulverized into dust as in the case of the towers, but are clearly still standing as can be seen in all the photographs. “… show they are making absurd comparisons and completely missing the point.

The summary “
No molten metal and certainly no thermate found
No column failure
No evaporation / pulverization of concrete
No "pancake collapse"
“…is just baffling. Evaporation of concrete? The gasoline caused the metal to soften and collapse. Dr Astaneh investigated the steel and confirmed that this was the cause. Pointing out irrelevant differences is just missing the point or hoping people will be convinced by their misdirection.

Yes you have posted this like 20 times. Spamming text is not taking part of a discussion. Can you please actually respond to the post you are replying to?

How is that letter insightful? It isn’t even correct and is attacking a claim which NIST does not make.

Yes I know Scott I have read it twenty times. NIST did not, at any stage, imply that the hottest temperatures reached were 250C. He is specifically referring to the temperatures recorded on the steel panels. While a question should be asked about these particular tests (regarding the selection of samples), it is not the only evidence of high temperatures. It wasn’t back then and it isn’t now so can you please stop posting this letter unless you have a new point to make.

 

perhaps discuss something less empirical, and more speculative ?

 

This is a pretty strong claim based on the actual testing NIST did for fireproofing removal by impact. You do know that all they did was fire 15 shotgun blasts at some SFRM coated steel in a plywood box right? There are serious questions about this testing.

Note: During the testing the gun mis-fired and produced an impact velocity of 31 m/sec. and the SFRM was not visibly damaged.

At 0.40 seconds into the impact of the North tower the average velocity of the debris cloud was computed to be 15.8 m/sec.

The alleged bowed columns were on the opposite side of the building from the aircraft entrance point.

Combining the area of the alleged bowed columns on the south side of the building with the computed debris velocity and the results of this testing actually disproves the extremely tortured theory that dislodged fireproofing caused the trusses to sag and perimeter columns to be pulled inward by the sagging floors and the initiation of collapse of the building.

When you combine this with the fact that there is no video evidence of bowed perimeter columns for minutes prior to collapse it is naive to not think that there is story concoction going on. Photo times can be said to be anything.

The perimeter columns did bow inward but it is much more likely that it occurred only after being pulled inward by severed core columns through the floor trusses. That is all we have video evidence of.

 

NIST's stated duty was to provide a "building and fire safety investigation".

Destroying all the steel was at odds with the purpose of a "building and fire safety investigation".

What reason was there to destroy all the steel from wtc7 ?
It was a neat pile with no bodies to reclaim.
The only plausible reason to destroy the steel was to destroy something that needed to be destroyed.

 

Unfortunately, like you say there is only one plausible reason why the steel would have been destroyed, and this fact alone destroys the credibility of the FEMA and NIST investigations and should make any thinking person suspicious.

This destruction of evidence alone is cause for a new investigation.

 

also the north tower tilted to the south as it collapsed, away from the entry point of the aircraft.

so it seems that failure occured on the face with the most fireproofing not on the face with the least fireproofing.

(which lends support to Kevin Ryan's nanothermite-spiked fireproofing/intumescent paint hypothesis).