9/11 No Longer Matters

I would doubt very much that the FLOORS were RATED to support 10 to 20 times their own weight much less that multiple of the live load.

But there are FLOORS and there are LEVELS. Are you saying the weight of the falling core of the north tower came down on the FLOORS outside the cores in the intact section below?

But the NIST gave up supporting the pancake theory long ago.

http://www.nist.gov/el/disasterstudies/wtc/faqs_wtctowers.cfm

psik

 

Keep running psik!! We both know the floors of a skyscraper are NOT so overdesigned that they can support many mutiples of their current load. Now, we all know you want to try and pretend the entire load was still carried by the core, but that isn't true. The entire upper section came down as one mass. What is going to prevent that load from hitting the floors? Absolutely nothing. I know it. You know it. You know the floors could not support that kind of weight even in your little fantasy land. Of course you also run away from the fact the core's integrity would be fatally compromised in the collapse as well. After all, the core can't bear weight if the columns aren't vertical. What do you think happens to the columns when the floor attachments pull away AND you have all kinds of debris inside the core pushing the core out.

We've discussed all this before. You never did come up with a rational, much less probable explanation.

 

Was does, "as weak as possible." even mean? You have a center dowel to correct for eccentricity in your loops that actually makes the structure very strong. You said your structure collapses without the dowel? Do you know why that is?

The WTC towers collapsed due to buckling. Your tower collapse models crushing of paper loops. The two are very different. Change your structural members to something with a much higher slenderness ratio and you'll understand what I'm talking about. I suggested spaghetti strands as an economical and easy swap, but you can try something different if you like.

In the buckling mode of failure the entire column loses the majority of its capacity to carry load. You can test this with a strand of spaghetti. Apply a load until the spaghetti begins to bend. This is the critical buckling load. In slender columns, this load is often much less then the ultimate yield strength of the material. This is because the bend causes the load to be applied eccentrically rather than axially through its center of gravity. Once you exceed the critical buckling load, the addition of more force causes the column to fail, and at this point it provides zero resistance to the load.

Your model doesn't recreate this situation. Once the initial drop takes place, since your supports have a very low slenderness ratio, they do not buckle. Since they do not buckle, they do not allow the mass from above to accelerate at all through the space where they once stood.

Wind load is a shearing force, not a compressive force. A structure can be built that could withstand massive amounts of wind load, but that could not support an equivalent amount of gravitational load. Conversely, one could be built to withstand massive amounts of gravitational load, that would withstand very little wind loading. The measure of a building's ability to withstand force in one vector is not a measure of its ability to withstand force in the other.

What's obvious is that you don't realize why your argument is specious, and that the model you use does not model the performance of the WTC in any way.

 

Now that is brilliant. The dowel is parallel to the gravitational force. The washers slide down it. The paper loops support the washers against gravity. They are crushed by the dynamic load created by gravity. The dowel is unaffected.

psik

 

Here's another test. Make a paper loop of the same diameter but much taller. I can't remember the dimensions of the loops you used, but if they are 1 inch high, try making them 10 inches high and observe the difference in capacity.

 

The dowel prevents eccentric loading. This contributes vastly to the stability of the model. You said so yourself. It falls down without it, right?

 

9/11 was an act of pure evil and, as with all such acts, has a place in history and education.
However, to be of value, the attack but be studied to find out the causes of such an evil event.

 

Oh wow, eccentric loading. Vocabulary is so impressive.

Yeah, as soon as it tilts it puts more weight on one side of the loops at the bottom and because THEY ARE SO WEAK that side collapses and the stack falls over. I have conducted that experiment. About 20 loops and washers is the maximum I can stack before it falls.

psik

 

Why? My dowel is only 4 feet tall. I had to allow enough height for the drop.

psik

 

If you understood what he was talking about, then you would understand why you're gaming your own "experiment".

 

I can't believe psik is STILL trying to pretend his retarded toy is somehow relevant. It doesn't model anything. It doesn't prove anything other than psik lacks the imagination to see one cannot build a four foot toy and pretend it accurately represents a thousand foot tall 110 story building with each floor covering almost an acre of land. The towers consisted of hundreds of thousands of parts, yet psik would have everyone believe it should act like a solid piece even during a collapse. Absolutely amazing!

 

I'm not talking about your entire series of loops. I'm talking about testing a single loop in the same way you tested to learn how many washers your loops will carry. Make 1 loop 10 inches tall instead of 1 inch and test to see if it will still bear 12-15 washers. Do you think it will hold more or less? What will the cause of failure be? Will it crush or buckle?

Why do it?

So that you can learn something. Heaven forbid.

Think about what you are saying. You said the dowel doesn't bear any of the load of the washers, right? If the dowel bears no load from washers, then it cannot affect the load carrying ability of the loops, can it? The loops are just as weak with the dowel as without the dowel, right?

What the dowel does it affect how the load is distributed. With the dowel in place, the load is concentrated axially along the center of gravity of the loops. With the dowel removed, the load is allowed to shift away from the center of gravity. This shift is what causes buckling. Since you have a big dowel, you've eliminated the structure's ability to buckle, and forced the loops to crush. This is the problem with your model.

 

You put so much effort into trying to show you are smart and presume you can talk other people into believing they are stupid. Maybe you spend too much time hanging around people that are less smart than you are. Tony Szamboti plays the same bullsh# games.

Do we need to talk about vector analysis? if the stack is leaning on the dowel what is the lateral force vector versus the vertical force vector? The dowel applies a trivial lateral force vector to prevent the tilt from increasing to keep the vertical force vector from becoming to great on one side of the paper loops at the bottom. It is going to be proportional to the sine of the angle of the tilt.

psik

 

Ever stop to think he IS smart and your posts are idiotic? ANYONE who thinks a retarded 4' toy somehow can accurately represent what happened in a 1000 foot tall, 110 story, almost one acre per floor building needs to have their head examined.

 

If you're having trouble with your self esteem after reading my post that's not my issue. Instead of taking offense, why not just test my conclusions on your own.

What we apparently still need to talk about is that your model isn't even self supporting, let alone self arresting. Without the dowel, your tower buckles in an almost ironically similar fashion to the WTC. What you just tried to say above is that the dowel eliminates eccentric loading which allows your model to stand. What you're missing here about that fact is that eccentric loading is what causes buckling. When you eliminate the moment induced by eccentric loading you remove the columns ability to buckle. If the column can't buckle then it will fail by crushing. Crushing failure takes far more force than buckling force. If you actually do the experiment I proposed, then you'll find this for yourself. It will take far fewer washers to induce failure in your 10" loop then in your 1" loop.

Essentially you created a model that by design can't model the collapse of the towers because it can't buckle, so that you can claim that since your model didn't collapse like the towers, then the towers should have collapsed like the model.

It's a fallacious claim which should be obvious to see.

 

http://www.youtube.com/watch?v=t18fCJnTIEM

Here's a great video that talks about exactly what I've been saying here. Watching the whole video wouldn't kill you, but if you want to skip ahead, you can start at about 8:10.

First he discusses the compressive strength of the column. He shows how this is calculated and shows just how resistant the column is to compressive force. At 11:10 he begins to discuss buckling. If you still dispute the obvious flaw in your model after this, there's not much more I can say to help you understand it.

 

Nice video actually.

There is one significant point. That Roman column was built 1900 years before Euler came up with that equation. Physics does not give a (*)(*)(*)(*) about mathematics. The math just helps people be more efficient ahead of time in some cases. The ancients probably had to be over cautious with their rules of thumb.

I tested the strength of my loops empirically under static loads. Doing the math afterwards would be nothing but idiotic busywork. Skyscrapers are not designed for minimum strength. I was not trying to put a safety factor in my stack.

But I watched video 19 where he talked about the WTC also. He said there were 47 columns on each side.

WRONG!!!

There were 59. And then when he discussed the collapse he disappeared the horizontal beams in the core and just talked about the trusses. He also did not say what percentage of the load was supported by the core and said nothing about the collapse time and the conservation of momentum.

I didn't watch the whole skyscraper thing but there was no mention of the distributions of strength and therefore steel down the building in what I heard. Otherwise decent.

psik

 

cp;
The math is a language that describes and predicts the properties of physics. It doesn't just "help people be more efficient...in some cases" It can help people understand that assumptions about properties are completely incorrect.

Clearly you didn't pay attention to the video at all. The column you tested is short and wide. It has a very high strength in comparison to the entire structure. Since your columns are not pinned together they should all function as a single column. You yourself admitted that the complete column is actually TOO slender, as without something to pin it to (the dowel) it buckles under its own weight. Since you pinned the column to the dowel, each column functions as an individual, rather then together as a unit. This forces the columns to fail in a crushing mode of failure rather then a buckling mode. Didn't you see the huge differences in material strength vs buckling strength?

Your model is arrested by the material strength of the paper, not the buckling strength. In fact, the model cannot stand on its own, as the buckling strength is too weak to support the structure on its own. This is not how the WTC tower should have behaved.

The WTC was a slender column. It did not fail due to a failure of the material strength of the steel. It failed due to buckling. To model the event, you need to create a model that can fail in buckling mode, rather then crushing mode.

 

Thanks for proving your ignorance on the towers. There were 47 columns in the core. The outer lattice consisted of 21 "box columns" per side, but they were not designed to carry much of the vertical load.



As for the horizontal beams in the core, they did nothing to support the floors and were designed to give the core it's rigidity. The floors were supported completely by the trusses which spanned from the core to the lattice.

 

So you didn't watch the video I was talking about.

The man said there were 47 columns on each side of the perimeter. He was not talking about the core. You didn't even read what I said.

All you could do was jump up and down shouting, "I caught psikey in a mistake." LOL

psik

 

I watched some of it. I caught one point where he talked about the WTC, but he didn't mention numbers. And you did make a mistake. A pretty retarded one I might add. Funny how all you can do is whine about other people's mistakes instead of manning up and admitting you made a mistake.

So even after watching that video, are you still insisting your retarded little toy made of paper and washers accurately models the WTC? To borrow a truther tactic of taking things to the absurd, does that mean we can build skyscrapers out of paper and washers that will never completely collapse? You need to grow up and realize your toy is not representative of anything but extreme ignorance of engineering and physics.

Oh, and anyone who says physics "does not give a (*)(*)(*)(*) about math" obviously knows nothing about physics as every element of physics can be demonstrated mathematically. In fact, one way you can prove the towers should not have collapsed like they did is to express the laws of physics you claim were broken mathematically. I've asked you to do that repeatedly. You've ran from that little challenge. Why? Because a mathematical representation is subject to scrutiny and refutation. When you only express your OPINION that it is impossible and then pretend a retarded little toy is somehow proof a 1000 foot tall, 110 story building couldn't have collapse, that is open to interpretation.

 

This "pinning" to the dowel is bullsh# you are making up. I admitted that my stack of paper loops and washers are leaning against the dowel via the inner edge of the hole in the washers. The paper loops do not touch the dowel while the stack is standing. The washers can fall straight down the dowel and cannot stick on the smooth surface in any way.

I provided sufficient data for you to duplicate it if you want. I presume you don't want since that would show you are talking nonsense. The Roman column did not support any load besides itself but was built without doing the math since the math did not exist at the time. Physics runs without math or are you saying Jupiter uses some language to talk to Saturn? Gravitational fields just are.

psik

 

I really wish you would simply look these things up before shooting off your mouth. Your dowel is the very definition of a pinned connection. Watch the video I posted again; specifically watch the point where he's talking about the first all steel warehouse. During his demonstration he shows the effect of a pinned connection in the middle of the column. With the pin in place, the column is restrained from deforming in the middle, and instead deforms above and below the pin. Note that the pin allows the column to slide up and down, but restricts lateral movement, just like your dowel. Your dowel is a pin, and it's connected to the columns through the column's connection to the flat washers.

It's not bull(*)(*)(*)(*), and I didn't make it up.

The problem is that you don't know what you're talking about.

A door hinge is a pinned connection. Can you tell me how your dowel is different from a pin in door hinge?

You thought I meant a fixed or clamped connection, didn't you? Come on. Admit it.

 

The lateral forces are trivial, dontchaknow?

I'm really enjoying this back and forth btw. I've been transported back to my undergrad structural design courses lo those many years ago. With the "crutch" of working with structural engineers on all my projects, I'm starting to remember how much I've forgotten......haha.

 

Physics doesn't care about your structural design courses. Apparently everything structural engineers have been teaching since before Euler is irrelevant. All that matters is that Psi's drop model crushed fewer loops than it contained. And that shows the WTC should have crushed too. Or something.