Video Nullfies Pancake/CD Theory

Originally posted by bottleslingguy
the outer and core columns were just stacked on top of each other and attached in sections come on you should know all this by now, it's been nine years already

are you suggesting the core and outer skin could stand without the floors? how about guy wires?

Sagging trusses do not act like guy wire. Again I think you are not understanding the word "sagging". Does that fact not enter your head when you think about this? Stop laughing stupid ain't funny, it's sad.

The core columns were welded sections. Welded steel can be stronger than the steel itself. So are you suggesting the welds broke? That the lightweight floors systems cause all the welds to break?

Seriously?

Oh BTW after 7 pages we seem to have drifted from the topic of the OP. Just to be sure it isn't buried in all the chit we're now wading in.

"Video Nullfies Pancake/CD Theory."

No it doesn't, fail.

Do you have yours?

reply to post by ANOK


Someone is explaining to you how the floors prevented the columns from buckling or falling over, and somewhere in that grey mass of your you come to the conclusion he is talking about sagging trusses.
He is explaining to you some very basic construction principles. You should pay more attention.

It is actually very similar to the mechanism by which the WTC towers gained their stability. They also did not have stabilizing triangles.

Yes, they had.

That photo mainly shows cranes used during construction. The perimeter columns and most of the core didn't have stabilizing triangles.

Sir, it seems we have no common ground to start from when you insist on denying photographic evidence of clearly visible diagonal beams within the core framework of the WTC towers. I am not going to argue the obvious, I've had this kind of discussion before and I will not spend my time photoshopping the picture to highlight the beams just to prove someone wrong in an internet discussion.

I am not talking about the small crane framework. I am talking about the triangles in the core framework, a concept that has been known and used for millenia. And in the WTC Twin Tower Cores. And any other steel-frame skyscraper.

Thats is why I suggest to use thicker paper or smaller paper. Maybe even envelopes.

Back to our experiment.

It went as I told you. With medium thick A5 paper, I was unable to stack more than 5 stories with the Jenga blocks upright (on their 1cm x 2.5 cm faces). When I tried to build the 6th floor, it swayed to one side and collapsed the way I predicted.

I think you agree that the twin towers were not so unstable that only the hands of god kept them aligned.

With the Jenga blocks on their small side (1cm x 7cm faces, second best of three possible configurations (upright, small side, broad side) in a Jenga brick) however, I easily built a tower 11 stories high. Again with the same medium thick A5 paper sheets. I dropped 10 Jenga blocks on it; from no little height, I might add (what a coincidence: 4x11 = 44 , 44+10 = 54 = 18*3 = number of Jenga blocks in one set :-).

(Please don't insist on my uploading the video evidence, I recorded it with my old cellphone in one hand and with bad lighting, the quality is terrible and I have no means to edit the video for the time I put the camera down and stuff).

Now it's your turn to guess how many floors went down with this structure.

To make things short: as I predicted - in my function as an "armchair expert" - within your parameters (Just with rectangle blocks (as seen here) and (thick) paper (Letter/A4). Place 4 blocks in each corner of a paper, place a paper on top of it, place again 4 block in the corners and so on, build it 10 stories high like this. then drop 10 blocks on top of the top paper), the building will either tilt and fall to the side. Or remain with its base standing intact and its top crushed. My prediction ( I predict for any structure stable enough to remain upright on its own that the collapse progression will stop after a few floors, depending on the stiffness of the structure. You'll be standing there and looking at a tower with its base intact, a small heap of "rubble" on top of its "crushing zone", and a lot of bricks laying evenly around your room. ) was right, yours ( I predict global progressive collapse.) was wrong.

It doesn't prove me right in the overall discussion, but it shows that your understanding of Newtons laws and physics in general has some room for enhancement. Progressive collapse from top to bottom doesn't work the way you think it works.

Please tweak the parameters for this experiment. For example, should I try to build the tower with only two columns, left and right, with the blocks on their small sides? Then it's not sooo stable when ten stories high. I can try with very thin A4 paper too, I had none at home yesterday.

Better yet, get some rectangle blocks at a garage sale and start building away for yourself. Toy around. That's what I did. A lot. My predictions were based on experience, not Wikipedia knowledge; this I use only for support. And to throw around with technical terms to sound smarter than I am :-)

Originally posted by Akareyon
My prediction ( I predict for any structure stable enough to remain upright on its own that the collapse progression will stop after a few floors, depending on the stiffness of the structure. You'll be standing there and looking at a tower with its base intact, a small heap of "rubble" on top of its "crushing zone", and a lot of bricks laying evenly around your room. ) was right, yours ( I predict global progressive collapse.) was wrong.

This can only be true if a single floor can hold those blocks in a static situation. If this is the case then the model isn't good. I am not sure exactly what you did, but I am confident that I will be able to tweak the model so that it does exactly what you asked for.

Please tweak the parameters for this experiment. For example, should I try to build the tower with only two columns, left and right, with the blocks on their small sides? Then it's not sooo stable when ten stories high. I can try with very thin A4 paper too, I had none at home yesterday.

Better yet, get some rectangle blocks at a garage sale and start building away for yourself. Toy around. That's what I did. A lot. My predictions were based on experience, not Wikipedia knowledge; this I use only for support. And to throw around with technical terms to sound smarter than I am :-)

I may give it a try, and give the blocks to my nephew afterwards

Originally posted by -PLB-
I am not sure exactly what you did

Exactly what you told me to do :-) And I described it as precisely as I can (I'm not a native speaker so sometimes I use strange ways to explain stuff that can be said with fewer words). Sheet of A5 paper, 1 Jenga block on each side -- repeat 11 times -- sheet of paper on top -- 10 Jenga blocks, drop. The drop height was around 6 to 8 stories, by the way (just checked the vid again).

I am confident that I will be able to tweak the model so that it does exactly what you asked for.

I am confident you will return with a model with gears and levers that doesn't even really work most of the time or you will have to throw a mortar brick on the tower to force the structure down :-)

Did I not promise you'll be proving my point instead of refuting it? You have to MAKE it so it collapses progressively.

I can hear them slither, those nasty, slimy worms in their hellish can, anxious for it to be opened...

I may give it a try, and give the blocks to my nephew afterwards

Yay, a new generation of architects is born :-)

Originally posted by -PLB-
I am not sure exactly what you did

Let me show you then.

reply to post by Akareyon


Nice job, though that is of course a much stronger construction than I suggested. The sheet of paper can hold the 10 blocks easily. That should not be the case if you want to model global progressive collapse. This was also not true in the WTC.

You can of cource increase the mass you drop to an equivelance of 5 or 10 stories, or 20-40 blocks. That may do the trick. For comparison, the WTC had to stop the mass of over 15 stories.

Originally posted by -PLB-
reply to post by Akareyon

 

Nice job, though that is of course a much stronger construction than I suggested.

It is the weakest 10-story construction possible within your parameters. I could have made it much stronger by stacking the blocks on their 2.5cm x 7cm side. I couldn't make it weaker for the reasons given. I will use ultra-thin A4 paper though.

The sheet of paper can hold the 10 blocks easily.

No, it gave way quite easily. It may not be visible, but one complete floor failed because the 4 blocks were pushed outward. This "used up" energy, which in turn was not available to crush a second floor.

Don't blame the paper. Blame physics.

That should not be the case if you want to model global progressive collapse.

I know how to model global progressive collapse, you're the one trying to prove it works without some kind of well-designed mechanism.

This was also not true in the WTC.

Worms, worms everywhere.

The only thing keeping my structure together is friction, this is not true in the WTC either. It was bolted and welded.

You can of cource increase the mass you drop to an equivelance of 5 or 10 stories, or 20-40 blocks. That may do the trick. For comparison, the WTC had to stop the mass of over 15 stories.

Yeah, let's increase the mass until it manages to crush the tower :-)

So tonight, I'll raise another 2 stories from the 10 pieces I had left and have a 13 story building. Then I'll drop the second Jenga game - in its box, the equivalent of another 13 story building - on top of it). Once with the same configuration as before. A second time with thin A4 paper. Each time from a height of 2 stories (I'll have two Jenga blocks left and can use these for calibration).

Ladies and gentlemen, fasten your seatbelts, switch off your phones, put on your safety glasses and place your bets if what we are going to witness will look like

a.) a progressive collapse
b.) the compression under excessive force
c.) the leaning, tilting and usual collapse of a badly built tower

Originally posted by Akareyon

Don't blame the paper. Blame physics.

No blame your model , your model like I said is NOWHERE near realistic and never can be!!!

It seems that some on here need to brush up on their reading comprehension, just because a building is classed as a tube design it does not make it identical to another building classed as a tube design.

Just like this is a car

So is this but they are not the same.


If you had bothered to read your own link you will see that tube designs have sub divisions.

From your own link

Variations
From its conception, the tube has been varied to suit different structural requirements;, the important part underlined just in case you miss it.

Framed tube: the most notable examples are the Aon Center and the original World Trade Center towers.

Trussed tube: The most notable examples incorporating steel bracing are the John Hancock Center, the Citigroup Center and the Bank of China Tower.

Bundled tube: Notable examples include Willis Tower and One Magnificent Mile

So that's the problem on here people who think they have an idea what they are talking about BUT don't fully grasp the true meaning or concept of what is being talked about or worse still when they can't even spot the difference in a photograph.

Then we have others that DO know about the subject due to education, training and REAL experience in that field.

Now back to your MODEL if an engineer want's to prove a building component /structural fixing is up to the task often on site a proof load test is done sometimes they will want a destruction test done, do they make a model to test it NO the real thing is tested, your model is not the same material , relative dimensions or properties so it cannot represent what you are trying to prove/disprove there are examples on the net of engineering papers,reports and even photographs of progressive collapse.

Collapse: Shortly after lunch, some workers observed slab deflections of about 6 inches to 2 feet (150 to 600 mm) for both the 23rd floor slab and the freshly placed 24th floor slab. The freshly placed section of the 24th floor slab then fell onto the 23rd floor slab, starting a collapse that continued all the way to the foundation (Schlager 1994)

This apartment building was in sections look at what happened after the floors of that section failed.

On March 3, 1973 the New York Times noted, “Six Killed as a Crane Drops Through Virginia Building.” The article stated that, “Six persons were killed, 34 injured and 14 were reported missing today in the collapse of a partly completed high-rise apartment building in this suburb of Washington D.C.” This article was published the day after the collapse. The initial hypothesis was that the crane itself was the cause for the collapse. The article states, “The falling crane broke through the top floors, its weight carrying with it layer after layer of concrete to the ground in a ‘domino effect

The North Tower had 15 floors above the impact point drop, the mass of the concrete in the floor slabs alone is more than 9000 tons never mind the steel and everything else THAT became a dynamic load, the South Tower was worse 30+ floors may be if you were ever on a site or had to say do things like TEST building components/fixings etc (part of my JOB!!!) you would have a real idea.

wmd.

reply to post by wmd_2008
I understand you are an expert who knows all about physics and I am an idiot who doesn't know the difference between a small car and a big car. I am probably also an idiot for thinking different models had different purposes and that they are called "models" because they model something - a certain aspect of a phenomenon that is to be studied, or else they would be called "replicas" or "copies". No, seriously, even as a kid I wondered why I couldn't sit in my matchbox cars and start the engine and drive away. The planetary model never made sense to me because I thought "who switches on the lightbulb in the sun then?". Really, I am so stupid. Glad you could help and shed some light on the matter that is being discussed here. Thank you so much.

Now that you have made so much fuzz about the fun-da-men-tal differences between tubular structures to prove me wrong on my initial objection to the claim that the tubular design was unique to the twins and has never ever been ever used ever again ever since the towers fell,

and now that you have so vigorously shown that I am absolutely clueless about the fact that tension/pressure increases the bigger something gets, given the same density (and that the architects of the WTC probably also were just as clueless as I and therefor did not make up for this by increasing the strength of the structure proportionally -- and thus the Twins had no choice but to fail),

please explain also the small, almost unnoticable, difference between something falling through a building and a building falling into and out of itself from top to bottom.

reply to post by Akareyon


Yes you have problems with comprehension!!



Nothing fell through that building but its OWN floors!!!

Collapse: Shortly after lunch, some workers observed slab deflections of about 6 inches to 2 feet (150 to 600 mm) for both the 23rd floor slab and the freshly placed 24th floor slab. The freshly placed section of the 24th floor slab then fell onto the 23rd floor slab, starting a collapse that continued all the way to the foundation (Schlager 1994)

Remind you of anything

reply to post by wmd_2008


This is the problem you folks have, not enough knowledge about physics and construction to understand the different between partial and complete collapse.

The floors collapsing in that building didn't bring down the frame of the building with them did it?

There is more to the WTC collapse than just floors collapsing.

The problem with your argument is not so much that floors fell and continued to progressively collapse, because that can happen, the problem is that doesn't happen to steel framed buildings, and when it does happen you usually have either a partial collapse, or with concrete structures you end up with a stack of floors, like a stack of pancakes (another term who's meaning seems lost on you).

The WTC collapses do not show any sign of "pancake collapse". As noted by your NIST report.

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...

So why do you keep trying to insist it was a progressive pancake collapse when even the report you all claim to be experts about, and defend so religiously, does not support that?

You have no evidence for your claims because the "evidence" you use is nothing of the sort.

Originally posted by wmd_2008
reply to post by Akareyon

 

Yes you have problems with comprehension!!



Nothing fell through that building but its OWN floors!!!

Collapse: Shortly after lunch, some workers observed slab deflections of about 6 inches to 2 feet (150 to 600 mm) for both the 23rd floor slab and the freshly placed 24th floor slab. The freshly placed section of the 24th floor slab then fell onto the 23rd floor slab, starting a collapse that continued all the way to the foundation (Schlager 1994)

Remind you of anything

I like the fact you take from your your example that tube in tube designs can pancake

And not that

Poorly designed/build buildings rarely get built (see your pic)

Originally posted by Akareyon
It is the weakest 10-story construction possible within your parameters. I could have made it much stronger by stacking the blocks on their 2.5cm x 7cm side. I couldn't make it weaker for the reasons given. I will use ultra-thin A4 paper though.

Those were not really my parameters. But ok, keep trying.

No, it gave way quite easily. It may not be visible, but one complete floor failed because the 4 blocks were pushed outward. This "used up" energy, which in turn was not available to crush a second floor.

Sorry for the vague response, I meant static load.

Don't blame the paper. Blame physics.

I blame your construction.

Worms, worms everywhere.

The only thing keeping my structure together is friction, this is not true in the WTC either. It was bolted and welded.

Yup, there are similarities and there are differences.

Yeah, let's increase the mass until it manages to crush the tower :-)

That is only because you made yours too strong.

So tonight, I'll raise another 2 stories from the 10 pieces I had left and have a 13 story building. Then I'll drop the second Jenga game - in its box, the equivalent of another 13 story building - on top of it). Once with the same configuration as before. A second time with thin A4 paper. Each time from a height of 2 stories (I'll have two Jenga blocks left and can use these for calibration).

Ladies and gentlemen, fasten your seatbelts, switch off your phones, put on your safety glasses and place your bets if what we are going to witness will look like

a.) a progressive collapse
b.) the compression under excessive force
c.) the leaning, tilting and usual collapse of a badly built tower

I have made a model myself, using dishwasher tablets . I managed to get global progressive collapse in my second try. The first try I had too thick paper. I made a video of it. I will post it as soon as I have figured out how to convert it into a gif.

So your challenge has been made using the model I proposed (though agreed, slightly different material).

Originally posted by -PLB-
I have made a model myself, using dishwasher tablets

. I managed to get global progressive collapse in my second try. The first try I had too thick paper. I made a video of it. I will post it as soon as I have figured out how to convert it into a gif.

You do realise making the model as weak as you can until you get a collapse is not proving a well built construction is going to do the same thing?

The point of making the model weak is to show that even a weak badly made structure will still follow the rules of physics.

If the WTC towers were built like that they would never have stood in the first place. Remember when steel framed buildings are designed each component as an FoS of at least three. The models you are making do not have this in their design, so they do not represent what the towers would have done. You will never be able to build a model that strong from paper and jengo blocks, so even if you make it as strong as you can it will still not have nowhere near the same relative resistance to collapse as the towers did.

Your model can only demonstrate the physical laws appropriate to a colliding objects, not how well the towers could withstand a collapse.

Originally posted by ANOK
You do realise making the model as weak as you can until you get a collapse is not proving a well built construction is going to do the same thing?

Of course I realize that. I also realize that it debunks your "it will slow down and arrest because of uuuuh physics" nonsense. My model proves, beyond any doubt, that global progressive collapse is possible.

Besides, my structure wasn't that weak. It was actually pretty stable.

The point of making the model weak is to show that even a weak badly made structure will still follow the rules of physics.

If the WTC towers were built like that they would never have stood in the first place.

What a nonsense. My structure stood. All self supporting. I could touch it. Even blow against it. It did not collapse.

Remember when steel framed buildings are designed each component as an FoS of at least three. The models you are making do not have this in their design, so they do not represent what the towers would have done. You will never be able to build a model that strong from paper and jengo blocks, so even if you make it as strong as you can it will still not have nowhere near the same relative resistance to collapse as the towers did.

Your model can only demonstrate the physical laws appropriate to a colliding objects, not how well the towers could withstand a collapse.

What happened to your "3rd law" "conservation of momentum" nonsense? Does the 3rd law and conservation of momentum not apply to my model?

My model was, like I clearly stated from the beginning not to model the WTC. But to model the concept of global progressive collapse.

Though making the model was easyer than uploading a gif to ATS :S.

Here is the gif. Ignore the ads.



And here is take 3, slightly different design, and this time only two blocks (or the mass of just 0,5 stories):



Did I just break the laws of physics by destroying a mass 20 times greater than the object I used to destroy it?

You can actually see the collapse accelerate. Which law did I break there again?

reply to post by ANOK

you asked what role the floors had in keeping the columns from falling and I said think of them as guy wires so you might be able to understand the design.

the floors sagged because when the concrete got hot it lost its tensile strength so it no longer contributed to holding its own weight and actually became part of the problem.

you really are a major intellectual stonewaller and I love how you change the subject or the point of a discussion when you don't want to go there. maybe if you could focus a little more on the really important aspects of the design and what effects the plane impacts had on those particular designs you may start to see light at the end of that 9 year tunnel.

reply to post by -PLB-

I'll guarantee one of them says "where's the smoke from the explosions?"