Video Nullfies Pancake/CD Theory

Originally posted by -PLB-
reply to post by waypastvne

 

The direction this is going puzzles me, as neither explosives or thermite give a better explanation for what we observed. The only direction this can go is "HAARP super secret space beam energy weapon". Or enlighten me on what people here actually think.

I don't actually know what AKAreyon thinks, but he does seem interested in how the buildings failed, and he will look at the evidence, and listen to the explanations. So I continue to reply.

Look, you don't have to speculate what I think. I said it twice alone in this thread already.

When I saw the towers collapse for the first time, I thought WTF, why do those towers crash?!? I was in Hamburg visiting my grandma on Sep. 11th, 2001, and my uncle just said "there were planes that crashed into the tower, remember?"

I left it at that. Then I got that infamous reopen911.org DVD and found out about all the other discrepancies about 9/11. I got very interested in all sorts of conspiracy theories, but more from an academic perspective, not because I really believe that earth is hollow and dwarves and dragons dwell on the inside waiting to return through the hole in Antarctica where Hitler and his minions disappeared with their third reich haunebu vril energy flying saucers.

After reading "The Shock Doctrine", I was happy to understand that you don't even have to believe that sinister forces make bad and terrible things happen, that it is conspiracy enough to know that sinister forces kneel by their bed each night praying to their g*d that something terrible may happen the next day - like a tsunami or a terrorist attack or a revolution - because they are anticipating it and have plans for those cases already in their drawers. So this is what I thought about 9/11: that it was a welcome opportunity for some to wage war (like the PNAC wanted to) and violate freedom and all the other human rights at home and abroad; and profit. Maybe, I thought, it was really some kind of domino effect that brought the towers down - after all, cube-square law and all that.

Last week I found out I have been calling for a model for the collapse a long time ago here on ATS, because I wanted to understand the collapse mechanism.

'twas on the tenth anniversary of the attacks that on gulli:board, one of the biggest German forums, a debate about 9/11 started and I meddled in and - just like here - I just dispersed some of the wrongest arguments (like, kerosene went down the elevator shafts and melted the whole core) and got immersed in a debate which led me to do some research again. That's how I stumbled over psikeyhackrs experiment and I was back where I once was: WTF?!?

I refreshed some high school knowledge about force and friction and got into a wild debate with a structural engineer on gulli:board who was willing to point me to resources and helped me a lot even though he supported the OT. The usual trolls were aboard too, of course. This is also why I formulated my letter to Bazant and Greening.

So unlike some here like to suggest, I am not absolutely clueless about the laws of physics. After all the debates, I even understood the energy conservation principle which went way over my head at school.

I still think that 9/11 was an inside job in the sense that there was a lot of energy "hidden" in each of the towers - in the form of potential energy that was not properly contained. Since there is no way to discuss this fact away, supporters of the OT must go so far to claim that all high-rises have their potential energy not contained properly and will fail catastrophically and disproportionally once a certain threshold is overcome, i.e. if any one floor below the second from the roof gives in due to some combination of fire, displaced columns and lack of fireproofing.

This is not to say that disproportional collapse is impossible. It is, but it requires a sort of mechanism, and for this mechanism to "work" as smooth, as symmetrically as it did in the towers, a lot of assumptions must be made. After all, we are talking about a building that swayed considerably during storms and hurricanes - and was designed to do so! - so obviously it was well secured against P-Delta effects. How can the same building not withstand the failure of one floor? It is fair to argue that the next floor would be crushed, but such an iterative process in turn suggests that the impact force would not be elastically caught by the whole intact structure underneath like in a huge spring.

So the last way to go is to argue that the specific design - the "spine" core, the "skin" perimeter and the "muscle" floor system - somehow formed a domino setup, a mechanism that went unnoticed which in turn suggests the engineers and architects are guilty of gross negligence and all the "research" done by NIST is to cover that up. Because they avoid so hard to come to any conclusion about the failure mode or to present a believable model that the absence of any explanation leaves a vacuum that is too willingly filled by all sorts of "conspiracy theorists" and gives birth to mini nukes, black tech and UFOs, so I'll stick with my black magic explanation: Lord Voldemort zapped the towers with the death star super laser to reset the matrix. And I can prove it.

On a more serious note: due to another conspiracy my internet access is strongly limited so I can't go hunting YT videos, but I consulted my external HD video archive with the collapse sequences yesterday trying to find that core structure still standing while the rest is still on its way down. It seems I am unable to verify that the core still stands while the rest of the tower is going down. That's odd. [eta: with that I mean the core up to the impact zone - the "spire" a little further down is clearly visible in most cases, though!]

You are missing the obvious. If the core truss connections did not fail at the truss seats, then they failed somewhere else.

Yes, I'm really missing something because sometimes they talk about the seats, then about the channels, then about the connectors. I also am not sure what this means:

Be aware that the truss seats on the channel are not always inline with the core columns, but attach to the channel at intervals in between the columns. Also note that the floor overlaps the channel this is what makes the channel the weakest link.

How do the channels attach between the columns? You mean they were attached to the horizontal beams between the columns?

The south wall failed first, it failed long before the core. The bow in the exterior columns show that it was no longer holding a compression load. The load that it used to hold was transferred to the core columns which failed second. When viewed from the north it looks like the core went first

I can't verify it right now, so I'll assume you are right. But it's still not clear what happened in which order. The trusses pulled the perimeter columns in, so they bowed inside? Or the trusses failed, so the perimeter columns bowed in? How could the trusses fail both on the core and on the perimeter columns - once they broke free on one side, they would be dangling from the other side, wouldn't they? Of course they were "heavy" in a sense, but they were relatively "light-weight" of course so it would be hard for them to crash through the next floor. It all sounds so easy when you say "all the mass went down, and peeled the perimeter panels to the outside like a banana, then the core was unsupported"... in reality, a light-weight floor slab would have trouble to rip free from both the core and the perimeter. I'm not sure about the Twins, but I would guess the floors were attached to the horizontal beams between the columns, so another attempt at explaining what happened would be that the floor pulled on these beams and thus transmitted the force needed to buckle the columns. But again, why should the columns not be able to considerably decelerate the mass it held aloft for so long, even if it smashed on the trusses that were hanging by its girder?

They are core columns. They are strait because they didn't fail from compression. They failed at the weld joints.

All columns visible in the rubble field failed at the weld points? So that would mean they had predetermined breaking points of sorts - is that not in conflict with the NIST reports saying the connections were good? Wouldn't someone during acceptance of construction work have noticed that and left the building with v_max? Shouldn't these columns have girders on both ends and at least one bracing beam for each floor? How did each of these joints fail so that dozens of columns look as if they had never been connected to anything?

reply to post by Akareyon

Originally posted by Akareyon

How do the channels attach between the columns? You mean they were attached to the horizontal beams between the columns?

Sometimes a photo is better than words The core columns, channels, and truss seats can all be seen in this photo.


farm4.static.flickr.com...

reply to post by waypastvne

That roughly corresponds to what I thought:

whatreallyhappened.com...

Beams bracing the core columns held up the floor trusses adjacent to the core column exoskeleton. But it's still unclear what happened during collapse. Were the "channels" torn off the bracing beams or were the bracing beams torn off the columns or did the trusses pull down the columns by the bracing beams? The NIST reports are quite detailed on what happened on the perimeter side of the trusses, but little is learned about the core. The core looks like a tight lattice on the photo you posted, so a lot of buckling and tearing would be required to pull it apart.

reply to post by Akareyon


wow i lose my phone and this thread stalls. lol . ok so where do we stand?

so far i think we have ruled out conventional cd and global gravitational symmetrical collapse as candidates .

but like plb said where does that leave us?

magic,space beams, finger of god? they all seem far-fetched but they are just as bad as ccd and ggsc.

Yeah, didn't want to bump without anything new to say, really. I re-read the thread again to find out what went wrong and it's still incomprehensible to me how this guy could accuse me of lying when I explained what I meant at every point and was the first to admit when I had erred. Especially that "purpose=energy" thing, I explained with the domino example and pages later I'm an disingenuous idiot for adding the energy needed for the calculator... Now I know what was meant with "character assassination", I guess. There's no way to talk away the fact that something very fishy was going on objectively, so let's kill the messenger and get into a debate about the definition of stable, metastable and unstable. But, alas, it's all there to read for everyone. The strongest point that was made for a gravitational progressive inproportional collapse eximplosion compression was a little gif showing a shaky mechanical dishwasher tablet tower disassembling itself and the explanation that all skyscrapers are built like it.

magic,space beams, finger of god? they all seem far-fetched but they are just as bad as ccd and ggsc.

There is another theory out there that I just want to mention for the sake of completeness, although it is also very "out there".

It has to do with the cold war. It goes like this: if you lose a town to the Commies, you don't want them to feel too comfortable in their new outpost. And that's why all major buildings, streets and bridges in Europe and the U.S.A. have a self-destruct mode built in. If you have to draw back, at least leave nothing of worth to the enemy. Scorched Earth, next level.

It may also be explained with "planned obsolescence". Today you know you won't own your phone for very long, it will be replaced next year by the newest one with a faster processor, larger memory and better display. What if a building becomes obsolete? Some say that if you want to build a skyscraper these days, you also have to propose a plan for its demolition in case it becomes outdated in, let's say, thirty years or so, and that's why buildings are built on purpose so they collapse into their footprint.

How much sense does that make? The Twins didn't collapse in their footprints, they distributed themselves all over the city and damaged adjacent buildings as they collapsed from top to bottom. Demolishing a building from the bottom up (like WTC 7 and other CCDs) is the way to go if you want to control where all the stuff is flying.

And another theory that hasn't been mentioned here is that the towers had a reinforced concrete core, which would explain the alleged lack of wind shear bracings (diagonal beams) and amount of pulverized concrete.

Those are all different possible causes we could continue to speculate on for another two decades and still come to no conclusion. Heck, there are still people who are adamant that all the skyscrapers in the world will just domino under their own weight once the conditions for initiation - full floor failure - are met and that there's nothing that can be done about it. They will insist that the silence in the official explanations is because such a never-before seen and - up to this thread unrepeated - collapse mechanism is self-explanatory, while others will fill that vacuum of knowledge with their own theories. That's why I refrain from any speculation what caused it, I just find the attitude of those who pretend that the collapse is explained in-depth by NIST, FEMA and Bazant and that all who question those explanations are idiots without any understanding of basic rules of physics ridiculous. They have just as little clue what happened as the tinfoil hat conspiracy nuts, but they have to rely on the official explanation because the rest of their world view depends on TPTB being too stupid or too benevolent to pull off such a trick. Even if Feynman himself got out of his grave to raise his voice and say with a thundering voice "this cannot be", it would be said he is not and never was an expert on structural dynamics and should stick to his bongos instead. BTW, I wonder if Feynman and Bazant ever met in real life...

It is possible that a lot more skyscrapers will be seen falling in the future, though. This will be seen as proof for either theory: that buildings just collapse like that because they have an effective FoS < 1 because of cube-square law, that all buildings are equipped with a mini-nuke powered self-destruct mechanism, that a SDI satellite is orbiting earth able to zap whatever it wishes with an electromagnetic death ray, that Newton's law has no power anymore over the realm of things taller than 350 meters, but as you said: one is as far-fetched as the other, and it will remain a mistery just as who killed JFK and why the pyramids of Gizeh were built.

Originally posted by Akareyon
How do the channels attach between the columns? You mean they were attached to the horizontal beams between the columns?

It would be better if you got the terminology correct at the core side of a floor truss the cleat that the truss rested on was attached to a rolled steel channel (that is the horizontal beam) which can be seen in the drawing below.



Then of course you had 1 acre or about 42000 sq ft of concrete on the steel decking to an average depth of about 4.5 inch (allowing for the profile) the concrete was stated as being a 115lb per cubic foot so doing the maths at least 1811250 lb of concrete per floor which would be 905 short tons(USA) or 808 tons (UK)

Now 808 plus tons dropping one floor generates one HUGE dynamic load never mind 15 or 30 floors of material

reply to post by wmd_2008

Then of course you had 1 acre or about 42000 sq ft of concrete on the steel decking to an average depth of about 4.5 inch (allowing for the profile) the concrete was stated as being a 115lb per cubic foot so doing the maths at least 1811250 lb of concrete per floor which would be 905 short tons(USA) or 808 tons (UK)

I have to ask, what was this concrete doing while the floor trusses were sagging and supposedly pulling in the perimeter columns?

Originally posted by Flatcoat
reply to post by wmd_2008

 

Then of course you had 1 acre or about 42000 sq ft of concrete on the steel decking to an average depth of about 4.5 inch (allowing for the profile) the concrete was stated as being a 115lb per cubic foot so doing the maths at least 1811250 lb of concrete per floor which would be 905 short tons(USA) or 808 tons (UK)

I have to ask, what was this concrete doing while the floor trusses were sagging and supposedly pulling in the perimeter columns?

The concrete would fail under bending load (concrete Doesn't like to bend) and Its mass weight would be resting on the top cord of the sagging truss.

Originally posted by wmd_2008
It would be better if you got the terminology correct

It would be better if I was grown up with the English language instead of learning it at school at the age of 10 when it's almost too late. You don't learn the word "cleat" at school, but I looked it up and I know what it means now. I cannot remember stumbling over it during my studies. I apologize for not always getting the terminology correct. I'm glad I know how to use interpunction better than some native speakers.

at the core side of a floor truss the cleat that the truss rested on was attached to a rolled steel channel (that is the horizontal beam) which can be seen in the drawing below.

I thought the "channels" were the things protruding from that horizontal beams seen in the photos above, sorry. That's how it sounded like in the NIST PDF I have linked to.

Now 808 plus tons dropping one floor generates one HUGE dynamic load never mind 15 or 30 floors of material

It better generates some titanic dynamic load, because it has to shear 95 or 80 floors times the numbers of channels off their columns and must accelerate 808 plus tons times 95 or 80 floors, otherwise, there will be no pancake.

You seem to be very knowledgeable about structural engineering. Per floor slab, how many channels, cleats and connections were there, and how strong would each be to accomodate the live load, according to your experience?

It all comes down to path of least reaistance. Once something shears or breaks or buckels it shifts the entire load to that weak point. Usually making it bigger. Like water flowing down a hill. Once one side goes (and yes one spot has to go first) the load shifts to that side and everything starts to fall to that point. The path of least reaistantance for both towers was down. Once the landslide begins it doesnt uphill route.

reply to post by Akareyon


I wasn't talking about the cleat I was talking about the channels which you seem to be confused with.

You had said this

Originally posted by Akareyon
How do the channels attach between the columns? You mean they were attached to the horizontal beams between the columns?

I said

Originally posted by wmd_2008
It would be better if you got the terminology correct at the core side of a floor truss the cleat that the truss rested on was attached to a rolled steel channel (that is the horizontal beam) which can be seen in the drawing below.

That's why I gave this link to the drawing to clear the issue up!



As for your other comment

Originally posted by Akareyon
It better generates some titanic dynamic load, because it has to shear 95 or 80 floors times the numbers of channels off their columns and must accelerate 808 plus tons times 95 or 80 floors, otherwise, there will be no pancake.

Do you honestly think that if an 800+ ton floor fell and hits another floor below it all energy and mass is lost because that's what you are implying above.

Of course one floor doesn't destroy the rest and that's a pretty disingenuous statement to make, the mass builds up as floor's fail.

As I an others have stated on repeated threads on here the NT had the mass of 15 floors dropping and the ST 30 floors.

As for this comment

Originally posted by Akareyon
You seem to be very knowledgeable about structural engineering. Per floor slab, how many channels, cleats and connections were there, and how strong would each be to accomodate the live load, according to your experience?

I am not a structural engineering but have some expertise that they find useful, I have worked in the construction industry for 30+ years having worked in the design/drawing office of a steelwork company and having a technical role for the last 15 years. I have tested building components/fixings with proof loads and sometimes to destruction both on and off site over many years.

Most structural engineers are happy with a 3 times safety factor on metal STRUCTURAL FIXING so with regards to your slab question it's mass plus any live/imposed loads x 3 would keep an engineer happy today.

So even if you round things up and said 1500 tons for everything it would be designed for 4500 tons now that would be a static load NOT a DYNAMIC load so 15 x1500 tons dropping in the NT would be 22500 tons falling and MANY times the designed static load with it's factor of safety and that's before the falling mass dynamic load is calculated.

Lots of people on here without the required knowledge used to make posts like this.

"Well the towers held up the floors for x years so would they collapse from those floors falling!"

That was of course because they have NO understanding of dynamic loads.

We have also had claims of the steel tested for several hours at 2400 degrees although it would be molten at that point.

Or that the building had a safety factor of "X" which would be a figure dreamed up or claimed on a 9/11 conspiracy site.

Safety factors put up costs its that simple.

Open plan floors suspended between walls was a real problem in this event as can be seen by the results.

Originally posted by wmd_2008
reply to post by Akareyon

 

I wasn't talking about the cleat I was talking about the channels which you seem to be confused with.

You had said this

Originally posted by Akareyon
How do the channels attach between the columns? You mean they were attached to the horizontal beams between the columns?

I said

Originally posted by wmd_2008
It would be better if you got the terminology correct at the core side of a floor truss the cleat that the truss rested on was attached to a rolled steel channel (that is the horizontal beam) which can be seen in the drawing below.

And I said

I thought the "channels" were the things protruding from that horizontal beams seen in the photos above, sorry. That's how it sounded like in the NIST PDF I have linked to.

Now I know better, thanks for clearing the issue up!

Originally posted by Akareyon
It better generates some titanic dynamic load, because it has to shear 95 or 80 floors times the numbers of channels off their columns and must accelerate 808 plus tons times 95 or 80 floors, otherwise, there will be no pancake.

Do you honestly think that if an 800+ ton floor fell and hits another floor below it all energy and mass is lost because that's what you are implying above.

No, I think energy is never lost, only converted from one form to another. At least that's what I've been taught at school and what most scientists agree upon. And I never implied any mass getting lost. All I am saying is that some of the kinetic energy of that dynamic load will have to be converted to deformation to shear, break, cut, smash and accelerate the next floor, and the next, and the next.

Of course one floor doesn't destroy the rest and that's a pretty disingenuous statement to make, the mass builds up as floor's fail.

Yes, I agree, it would be a very disingnenuous statement to make that one floor destroy the rest, however, it is the official story and the NIST reports -- that I'm arguing against! -- which make that very statement: the failure of one floor led to progressive collapse, destroying the rest.

As for the mass building up, I'll catch up on that later.

As I an others have stated on repeated threads on here the NT had the mass of 15 floors dropping and the ST 30 floors.

Yep, and as we all now 15 floors brought 95 floors down and 30 floors brought 80 floors down.

Originally posted by Akareyon
You seem to be very knowledgeable about structural engineering. Per floor slab, how many channels, cleats and connections were there, and how strong would each be to accomodate the live load, according to your experience?

I am not a structural engineering but have some expertise that they find useful, I have worked in the construction industry for 30+ years having worked in the design/drawing office of a steelwork company and having a technical role for the last 15 years. I have tested building components/fixings with proof loads and sometimes to destruction both on and off site over many years.

Most structural engineers are happy with a 3 times safety factor on metal STRUCTURAL FIXING so with regards to your slab question it's mass plus any live/imposed loads x 3 would keep an engineer happy today.

So even if you round things up and said 1500 tons for everything it would be designed for 4500 tons now that would be a static load NOT a DYNAMIC load so 15 x1500 tons dropping in the NT would be 22500 tons falling and MANY times the designed static load with it's factor of safety and that's before the falling mass dynamic load is calculated.

Yes, I totally understand the pancake collapse logic. In the end, it's the mass of 109 floors crashing onto the last floor - voilà, collapse complete.

It seems to be a recurring problem in the debate that one side believes the other one does not comprehend their logic.

However, now all floor slabs should be neatly stacked on ground level, the perimeter and the core still standing -- enter the argument that the core and the perimeter depended on the floor slabs for stability and so they collapsed next, which is just a nice way to formulate the allegation the towers had a built-in mechanism: first, the floor slabs pancaked, then the perimeter peeled outward under its own weight, then the core collapsed.

However, both perimeter and core should be more stable after all the floor slabs have collapsed, as they don't have to carry the 165000 tons of live load anymore.

reply to post by Akareyon


Again you take a to simplistic view of the collapse do you really think that it's not total chaos during the collapse do you honestly think that the mass falling inside the walls does not in any way impact with the outer or core walls

It's NOT a clean drop top to bottom with no impacts occurring to the walls the outer walls had structural damage the ST fell at an angle to start with the cores would sustain impacts as well.

You have to LOOK at everything together not isolate parts to try and prove a point.

You want pancaked floors look here.

www.stevespak.com...

You can see truss steel , decking etc happy now

Originally posted by Akareyon
However, both perimeter and core should be more stable after all the floor slabs have collapsed, as they don't have to carry the 165000 tons of live load anymore.

edit on 11-6-2013 by Akareyon because: (no reason given)

What makes you think this? I know in your research you've come across the concept of unbraced length and p-delta effects. Why would you think the towers would be more stable without the floor slabs and trusses? How would perimeter walls resist the force caused by a strong wind?

Originally posted by exponent

Originally posted by Akareyon
However, both perimeter and core should be more stable after all the floor slabs have collapsed, as they don't have to carry the 165000 tons of live load anymore.

edit on 11-6-2013 by Akareyon because: (no reason given)

What makes you think this? I know in your research you've come across the concept of unbraced length and p-delta effects. Why would you think the towers would be more stable without the floor slabs and trusses? How would perimeter walls resist the force caused by a strong wind?

As you can see in the spire videos there was no buckeling. You cant invoke euler as most do to explain away those spire as the all the steel in the photos shiw 99% straight pieces. Like they werr cutnot buckeled.

Originally posted by wmd_2008
reply to post by Akareyon

 

Again you take a to simplistic view of the collapse do you really think that it's not total chaos during the collapse do you honestly think that the mass falling inside the walls does not in any way impact with the outer or core walls

Everybody who payed attention in this thread knows that I do think that there was total chaos during the collapse and that the mass falling inside the walls would impact with the outer and core walls and therefor lose kinetic energy in the process. However, that is not what happened. Only one third of the kinetic energy was lost. I was just trying to be optimistic towards your proposal.

It's NOT a clean drop top to bottom with no impacts occurring to the walls the outer walls had structural damage the ST fell at an angle to start with the cores would sustain impacts as well.

You have to LOOK at everything together not isolate parts to try and prove a point.

Pff, that's MY argument you're using here. I have been looking at everything together and shown that 2.1 GJ triggered the conversion of 981 GJ of potential energy to kinetic energy and that an effective FoS of around 0.3 is needed to make progressive axial collapse in less than 20 seconds possible. Apparently, that was too straight-forward and the out-thereness of the OCT became a little too obvious, so I've been told you have to isolate parts and look iteratively at the thing. So now I'm isolating parts and look iteratively at the thing to explain how such a auto-destruct mode would have to work, and now that's not correct either.

Originally posted by Another_Nut
As you can see in the spire videos there was no buckeling. You cant invoke euler as most do to explain away those spire as the all the steel in the photos shiw 99% straight pieces. Like they werr cutnot buckeled.

They were cut, in 36 foot sections when they manufactured the towers in the first place.

Secondly, of course the spire videos show buckling. It occurs at the base. Do you think the core columns would somehow suffer an overload related failure in the middle of the air? Of course it occurs where the stress was concentrated most.

Originally posted by Akareyon
an effective FoS of around 0.3 is needed to make progressive axial collapse in less than 20 seconds possible.

You seem to keep making this mistake. The towers did not collapse because there was too much energy. It's not a question of the amount of energy, it's a question of the forces and the geometry. There's no trivial way to summarise this as an 'effective factor of safety'. Please stop using it, it's meaningless.

Apparently, that was too straight-forward and the out-thereness of the OCT became a little too obvious, so I've been told you have to isolate parts and look iteratively at the thing. So now I'm isolating parts and look iteratively at the thing to explain how such a auto-destruct mode would have to work, and now that's not correct either.

The isolated and iterative analyses are techniques used in FEAs to simplify the problems so they can be resolved by computers. I don't see you doing an FEA or p-delta calculations. These are what are needed in order to support your point.

I don't disagree with you much, but you seem so confident there's something dodgy to find that you miss out all of the important knowledge in your rush to the answer.