yup ... indeed ..

reply to post by -PLB-


You seem to like PFD's, so here is one for you to add to your research.

Here are some excerpts...

“Catenary Action”; collapse resisted through tensile forces

“Flexural Action”; collapse resisted through bending/membrane response

www.dtic.mil...

For more understanding refer to the images in the PFD. Note that tie forces, in the case of WTC 1&2 1" and 5/8" bolts, resist collapse from catenary action. If there is too much force then the ties will fail, not the columns they are tied to. All literature I can find online supports this.

Wreply to post by ANOK


You finally decided to put the words I talk about in Google, very good, you are starting to do some research. Although the document you found is about another mechanism, but it still uses some of the same words. It isn't about fires, it isn’t about sagging beams or trusses, and it isn't about structures like the WTC towers. Still this could also have occurred in the WTC towers, it could partly have been responsible for the inward bowing of the perimeter columns that was observed.

So ANOK, do you finally understand that when they talk about tensile forces (which is an axial force) ins the beams/trusses it means there will be a pulling force on the columns? Because acknowledging that would be the first step in understanding the mechanism that NIST is talking about. And that would be a great victory for yourself, to finally understand a bit better what you have been attacking and dismissing all these years.

Originally posted by -PLB-
Wreply to post by ANOK

 

The NIST report is just a hypothesis, you take their 'guess' at what happened all too seriously.

Why do debunkers like yourself rely so heavily on a report that is massively flawed due to lack of evidence collected, and very bad calculations? Maybe you do not understand the report so well?

reply to post by -PLB-


So where is the evidence for this pull in you claim can happen?

Why is there no literature that shows this?

Why did you post a PDF claiming it showed this when it didn't?

Why do you ignore a PDF I post that is more on point than the one you posted?

Why are you trying to argue against these technical reports that you yourself wanted me to look at?

Do you feel silly when your own "evidence" is turned against you?

Do you know what an hypothesis is?

BTW NIST also said this, on pages 180, and 181 of the Final Report...

“None of the recovered steel samples showed evidence of exposure to temperatures above 600ºC for as long as 15 min"

This is for the outer columns...

“Only three [out of 171] of the recovered samples of exterior panels reached temperatures in excess of 250 ºC during the fires or after the collapse. This was based on a method developed by NIST to characterize maximum temperatures experienced by steel members through observations of paint cracking.” (NCSTAR 1, 181)

NCSTAR 1-3C, “Damage and Failure Modes of Structural Steel Components”,

“After only 15 minutes of exposure at 625ºC, 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 minutes."

NCSTAR 1-3

“Annealing studies on recovered steels established the set of time and temperature conditions necessary to alter the steel microstructure. Based on the pre-collapse photographic evidence, the microstructures of steels known to have been exposed to firewere characterized. These microstructures show no evidence of exposure to temperatures above 600º C for any significant time.” [8]

So where is the evidence steel even got hot enough to do anything that they claim?

Then there is their truss test...

“All four test specimens sustained the maximum design load for approximately 2 hours without collapsing.” (NCSTAR 1, 143)

“…in all cases, the floors continued to support the full design load without collapse for over 2 hours.” (NCSTAR 1, xli)

NIST also said this....

“…, the towers withstood the impacts and ….would have remained standing were it not for the dislodged insulation (fireproofing) and the subsequent multi-floor fires.” (NCSTAR 1, xxxvii, 175)

Where is their evidence for dislodged fireproofing? There is no evidence the fires were hot enough to cause column failure, without even getting to the sagging truss nonsense. It is nothing but a claim, an hypothesis they could not repeat in the lab, it will never become a theory, unless we change the laws of physics.

reply to post by DeeKlassified


Its not just a guess. There is photo and video evidence of inward bowing, so we know it happened.

Where is the photo and video evidence of the explosives? Why do you need explosives anyhow if we can observe that the inward bowing resulted in structural failure?

Originally posted by ANOK
So where is the evidence for this pull in you claim can happen?

We are talking about pull-in force, which is nothing more than tensile forces in the beams/trusses. Evidence was in that document I linked.

Why is there no literature that shows this?

There is. A lot. Its even very easy to find. Just spamming random links:
www.fire-research.group.shef.ac.uk...
fire-research.group.shef.ac.uk...
www.arup.com...
www.civil.canterbury.ac.nz...
www.ceric.net...(C).pdf
www.ceric.net...(C).pdf
I could go on for some time.
Are you still denying that heating leads to sagging leads to catenary action leads to tensile forces? Are you saying that all those publications are wrong?

Why did you post a PDF claiming it showed this when it didn't?

It did show this. Including experimental data. In that PDF, what happens when the lines cross the x-axis in figure 5b? You really have no clue what you are looking at do you? Why do you keep avoiding this question?

Why do you ignore a PDF I post that is more on point than the one you posted?

It’s not. It is not about fires, it is not about sagging beams/trusses, like I just told you in the post you replied to.

Why are you trying to argue against these technical reports that you yourself wanted me to look at?

I am not arguing against it. I am pointing out that it is a different mechanism NIST is talking about. I can’t help that your understanding is so bad that you don’t notice the difference.

Do you feel silly when your own "evidence" is turned against you?

If you would have succeeded, I may have felt silly. But you don't even understand that you failed.

Do you know what an hypothesis is?

Yes

So where is the evidence steel even got hot enough to do anything that they claim?

How about the photo and video evidence of columns bowing inward?

Then there is their truss test...
“All four test specimens sustained the maximum design load for approximately 2 hours without collapsing.” (NCSTAR 1, 143)
“…in all cases, the floors continued to support the full design load without collapse for over 2 hours.” (NCSTAR 1, xli)

Which fully support the fact the bolts didn’t fail as you keep claiming. How does it feel when your own evidence backfires?

NIST also said this....

“…, the towers withstood the impacts and ….would have remained standing were it not for the dislodged insulation (fireproofing) and the subsequent multi-floor fires.” (NCSTAR 1, xxxvii, 175)

Where is their evidence for dislodged fireproofing? There is no evidence the fires were hot enough to cause column failure, without even getting to the sagging truss nonsense. It is nothing but a claim, an hypothesis they could not repeat in the lab, it will never become a theory, unless we change the laws of physics.

Again, there is photographic and video evidence. It’s all documented in their reports.

The fact that you deny all the conclusions by NIST has absolutely nothing to do with science. It has everything to do with your preconceived conclusion. I think that is why you spread lies and try to do character assassination. The core of your belief is attacked.

I have challenged you before to come with an explanation for the inward bowing that was observed. And no, its not an effect of the aluminium cladding. That is physically impossible and was explained to you. The space between the columns and the cladding is not 50+ inch that was observed.

Originally posted by DeeKlassified

Originally posted by -PLB-
Wreply to post by ANOK

 

The NIST report is just a hypothesis, you take their 'guess' at what happened all too seriously.

Why do debunkers like yourself rely so heavily on a report that is massively flawed due to lack of evidence collected, and very bad calculations? Maybe you do not understand the report so well?

Maybe this will make it clear enough to see.

reply to post by wmd_2008


It is amazing how there are people who keep denying that there was inward bowing of the perimeter columns before collapse initiation. I can understand that it is inconvenient as it does not go well with explosives, but still, it is very odd that someone would just willingly ignore actual visual evidence, and just claim that NIST theory is based on nothing.

Originally posted by wmd_2008

Originally posted by DeeKlassified

Originally posted by -PLB-
Wreply to post by ANOK

 

The NIST report is just a hypothesis, you take their 'guess' at what happened all too seriously.

Why do debunkers like yourself rely so heavily on a report that is massively flawed due to lack of evidence collected, and very bad calculations? Maybe you do not understand the report so well?

Maybe this will make it clear enough to see.

Thought we were talking about building 7 ? I don't deny this gif,sure the building bowed ....a plane hit it?? ...building 7 show me the same gif ?

reply to post by LightningStrikesHere


For building 7 there is the internal collapse as evident by the penthouse collapse. Internal collapse is consistent with NIST's theory, as they based their theory on the evidence that was available. As far as I know there isn't a single case of controlled demolition that shows a similar feature. Controlled demolition videos do however consistently show explosions, both visible and audible, something that was not seen at all in WTC7 videos. So also in case of WTC7, NIST's theory is based on evidence, CD theories are based on imagination.

For the gif: thewebfairy.com...

reply to post by LightningStrikesHere


Where is the evidence that sagging trusses caused that to happen?

But who made that gif? Because if you look at vids of the collapses you don't see that happen...



What you see is the top tilting because the lower building is resisting collapse. The top at angular momentum cannot crush floors downwards, because the force of the top is not symmetrical, and it is pivoting on one edge. The angular forces should have made the top continue it's tilt, if the pivot point gave out it would not take the whole building down with it, just the point that it's force is concentrated on. It's not going to suddenly change it's mind and fall vertically unless something causes the resistance to give way, which because of angular momentum should have only been the edge it was pivoting on. It is not going to cause a complete symmetrical global collapse.

Even IF the top was perfectly symmetrical it would still not crush all the floors, basic physics, a small mass cannot destroy a larger mass. 15 floors cannot crush 95 floors. The tilt proves that it couldn't have crushed the floors because it tilts. Have you ever hammered a nail and not hit it straight on? The nail will not go straight down (assuming it doesn't just bend). You cannot make anything completely crush if the tool used is not hitting the object square on.

But what is missing is the explanation of how sagging trusses can pull in columns, it's not physically possible mate. Lightweight trusses do not have the force to pull in columns they are attached to, IF any pull forces was created by the sagging trusses the 1" and 5/8" bolts would have failed first. You can't possibly believe the bolts were stronger than the columns? Take a steel bar and a bolt and see which one fails first, I can grantee you the bolt will fail first. As a mechanic who has wrenched bolts on jet engines, propeller systems, helo rotor heads, I can tell you this is a FACT.

Originally posted by SpearMint
It would appear to make no sense (although it apparently does to architecture experts), but then demolishing the building doesn't either. There's no way they could have put the insane amount of charges needed to bring down the tower in place without being noticed. You need to consider this before dismissing the official story.

edit on 9-4-2013 by SpearMint because: (no reason given)

High rise buildings have maintenance access floors that everyone else does not know about. The landlord does not want his maintenance guys running around his customer's businesses dragging their tools, lubricants, and explosives around the customer's employees. I am not 100 percent sure that this feature was included, but when I was designing form work for cast in place high rise construction, every single building I worked on in the mid to late seventies included this feature. My opinion from that experience is that it would be pretty easy to grub around behind the facade of the offices and not be noticed. Maintenance people even have their own special elevators that nobody else is supposed to access.

It could also have been done after business hours.

The owner of the wtc got a 4.55 BILLION dollar insurance payout.

Saying no one could have got in to plant "explosives" obviously has no idea what they're talking about.

It would not have been hard for a government agency to get the permits to enter the buildings using a bogus maintenance order.

The only person that checks you is the guy at the front desk, if the paper work is correct they get in.

I used to be a bike messenger in a major city, so I spent lot's of time in high rise office buildings and maintenance goes on constantly. No one even looks twice at you in a building the size of the towers, because they're filled with thousands of people.

But regardless physics doesn't give a damn about any of this, you can come up with excuses all day, but the physics remains the same, and it's the physics you guys have a problem understanding. Not sure of that is done purposely, or you're just embracing ignorance.

Originally posted by SpearMint
There's no way they could have put the insane amount of charges needed to bring down the tower in place without being noticed.

Do you not realise what a contradiction that is?

If it would take an insane amount of explosives to bring it down, then why do you believe it took no explosives?

reply to post by ANOK


Between blaming the gif and this gem...

15 floors cannot crush 95 floors. The tilt proves that it couldn't have crushed the floors because it tilts. Have you ever hammered a nail and not hit it straight on? The nail will not go straight down (assuming it doesn't just bend). You cannot make anything completely crush if the tool used is not hitting the object square on.

I want to know who the hell could give you a star??

Gravity. It was gravity. There is no need for specific tonnage. That is just a way to make people go away and not engage you. Here is a real simple test.

Hold you hands above your head and extend your fingers. Now, put as much weight as you can hold on said fingers until you cannot hold anymore.... To your breaking point. Now, move 3 fingers and what happens? It will all fall. Gravity takes over.

Originally posted by esdad71
reply to post by ANOK

 

Between blaming the gif and this gem...

15 floors cannot crush 95 floors. The tilt proves that it couldn't have crushed the floors because it tilts. Have you ever hammered a nail and not hit it straight on? The nail will not go straight down (assuming it doesn't just bend). You cannot make anything completely crush if the tool used is not hitting the object square on.

I want to know who the hell could give you a star??

Gravity. It was gravity. There is no need for specific tonnage. That is just a way to make people go away and not engage you. Here is a real simple test.

Hold you hands above your head and extend your fingers. Now, put as much weight as you can hold on said fingers until you cannot hold anymore.... To your breaking point. Now, move 3 fingers and what happens? It will all fall. Gravity takes over.

But gravity pulls it to the weak side ... The side of least resistance.


100lbs will not crush my 215 lbs @ss to dust

Period.

Originally posted by Another_Nut

Originally posted by esdad71
reply to post by ANOK

 

Between blaming the gif and this gem...

15 floors cannot crush 95 floors. The tilt proves that it couldn't have crushed the floors because it tilts. Have you ever hammered a nail and not hit it straight on? The nail will not go straight down (assuming it doesn't just bend). You cannot make anything completely crush if the tool used is not hitting the object square on.

I want to know who the hell could give you a star??

Gravity. It was gravity. There is no need for specific tonnage. That is just a way to make people go away and not engage you. Here is a real simple test.

Hold you hands above your head and extend your fingers. Now, put as much weight as you can hold on said fingers until you cannot hold anymore.... To your breaking point. Now, move 3 fingers and what happens? It will all fall. Gravity takes over.

But gravity pulls it to the weak side ... The side of least resistance.


100lbs will not crush my 215 lbs @ss to dust

Period.

Does it? Or does it fall straight down? You cannot combine the entire event into one thing.

Let me put it this way.

Everything structurally is fine. Then the planes hit. When the upper floors are not long distributed evenly, it slowly starts to weaken. After an hour of trying to hold it, there is the initialing final event, or, the buckling of the outer columns. You can see this in video and pictures. It happens.

When that happens, the rest of the structure fails. The immense weight is 'pulled down by gravity'. Nothing is 'pulled' to the side in this but it it simply fails to be able to hold the weight it was desgined to hold.

as it is falling towards earth it is then 'pulled' by gravity. When that weight hits the floor below it fails,since it was not designed to hold that much weight.

Also, please try not to be so literal. I am trying to use a basic physical example of not being able to hold the weight. No one said you would be crushed to dust. The dust was drywall, not steel.

Originally posted by ANOK


Even IF the top was perfectly symmetrical it would still not crush all the floors, basic physics, a small mass cannot destroy a larger mass. 15 floors cannot crush 95 floors. The tilt proves that it couldn't have crushed the floors because it tilts.

Why do you keep saying crushed? The proper word is sheared. After collapse initiation nothing needed to fail in compression, (for the collapse to continue) only shear.

As the floors fell and impacted the floors below they sheared off these truss seat brackets:




on every floor, one floor at a time:




all the way down, until they came to rest at ground level.



This is evidenced by the fact that all the truss seats are missing or damaged on all the exterior columns seen in photos like this one.

Nothing needed to be crushed, nothing needed to fail in compression,

Originally posted by ANOK

Where is the evidence that sagging trusses caused that to happen?

It’s called the NIST report. They simulated the effect using computer models, and concluded that it is a very likely candidate for that to happen. The even created experimental models.

Or what kind of evidence do you want? I aready linked you a whole bunch of publications about pull-in effects of sagging trusses. You of course ignored that post, as you do with most posts that are inconveniently showing you have been wrong all this time.

reply to post by waypastvne


OK, so if the floors easily became detached from the columns, then how the hell did they stay attached when they pulled in the columns?

What can withstand the most force, weak connections, or vertical box columns. Think about that PLB, you are the one who just informed us of how weak those connections were.

Hmmm?

Crush is just a generic term, I think most people understand what is meant by that. Using big words like "shear" does not improve your argument.

So now you no longer have that PDF to throw up as "proof" of catenary action, what is your new excuse for the sagging trusses having enough force to pull in columns? Without breaking those weak connections you just told us all about?

Hmmm?

And where is the pile of floors from this pancake collapse? An argument even NIST dismisses. You are just making this up PLB, seriously.

From your keepers...

NIST’s findings do not support the “pancake theory” of collapse, which is premised on a progressive failure of the floor systems in the WTC towers (the composite floor system—that connected the core columns and the perimeter columns—consisted of a grid of steel “trusses” integrated with a concrete slab; see diagram). Instead, the NIST investigation showed conclusively that the failure of the inwardly bowed perimeter columns initiated collapse and that the occurrence of this inward bowing required the sagging floors to remain connected to the columns and pull the columns inwards. Thus, the floors did not fail progressively to cause a pancaking phenomenon.

www.nist.gov...

Did you guys just not read that part? They did not explain how the collapses were complete, so don't pretend you know.

Nope, the only thing they did is offer an hypothesis for collapse initiation. Something that cannot be demonstrated because it just couldn't happen, all tests and literature concerning centenary action show this, including ironically the PDf you PLB posted as proof of NIST's claim.

So how is that electrical engineering job going there PLB?