Thread: 9/11 No Longer Matters

Reality didn't work before mathematics was invented?

The Romans didn't really build that column 1900 years before Euler came up with that equation.

Math has to conform to physics. Physics is inanimate and incapable of giving a (*)(*)(*)(*) about anything.

psik

I don't know why you keep trying to deflect with this nonsense. I know I'm not distracted by it. We get it. You don't know how to describe the collapse with math. That's fine.

What's annoying is that you refuse to admit that your model supports a flawed argument. I've explained to you why your model does not describe, model, or even remotely resemble the collapse of the WTC. I've done so with fancy calculus that you don't understand in the past, I've done so with simple physical models most recently. Your model shows crush failure mode of the design of your paper loops. It does not show or represent the failure mode of the design of the WTC buildings.

Now, back to the discussion where we left it. Are you willing to admit that your columns are pinned by the center support dowel, and that the center support dowel creates an unreasonable amount of stiffness in a structure purported to model the collapse mode of the WTC towers?

Originally Posted by psikeyhackr

The egg came first. It was laid by a dinosaur.

Ask Darwin.

psik

Don't sell yourself short on egg laying psikey. You've filled up a carton in this thread alone.

Originally Posted by Fangbeer

I've explained to you why your model does not describe, model, or even remotely resemble the collapse of the WTC. I've done so with fancy calculus that you don't understand in the past, I've done so with simple physical models most recently. Your model shows crush failure mode of the design of your paper loops. It does not show or represent the failure mode of the design of the WTC buildings.

So you can tell us the weight of the trusses and steel pans of a standard floor assembly?

Because if you can't than you can't have put correct data into your equations.

Are you saying my model does not use gravity to accelerate mass onto supports which can hold their static load? I have never claimed my model was a tube-in-tube structure. That would be much more difficult and expensive to build. But it can't be built without accurate data on the buildings anyway. So where is the engineering school that has built a physical model of the WTC that can completely collapse. It is certainly curious that none has been able to do it in TEN YEARS.

But then I haven never heard of any claiming to try.

I am not going to bother responding to that "pinned" bullsh# again.

psik

So you can tell us the weight of the trusses and steel pans of a standard floor assembly?

So when you can't answer for the blatant problems with your model, your response is to attempt to attack the NIST model? The data you seek is in the SAP2000 model.

Because if you can't than you can't have put correct data into your equations.

Didn't you say this isn't about math? Now it's about math? Are you serious with this?

Are you saying my model does not use gravity to accelerate mass onto supports which can hold their static load?

I'm saying you are oblivious to the different types of failure modes of structural systems. Your structural system fails in a crush mode which takes far more force then a system that fails in a buckling mode. With your model as an example it takes very little force for the dowel-free design to buckle. In fact, the force is so little that it can't even support its own weight. The dowel's stiffness is what supports your structure and prevents collapse due to buckling. Without the dowel, your structure collapses in a manner quite similar to the WTC.

I have never claimed my model was a tube-in-tube structure. That would be much more difficult and expensive to build. But it can't be built without accurate data on the buildings anyway.

I keep telling you that even if you had EXACT data down to the weight of every last stapler in the building you STILL couldn't build a scale physical model that behaves the same as the full size model. Square cube law and the inability to scale gravity or material strength precludes this notion.

So where is the engineering school that has built a physical model of the WTC that can completely collapse.

They can't build something that cannot be built.

It is certainly curious that none has been able to do it in TEN YEARS.

It's not curious at all. What's curious is that you haven't figured out why in ten years.

But then I haven never heard of any claiming to try.

I have heard of people claiming to try all sorts of things that are physically impossible. This doesn't make them educated. On the contrary...

I am not going to bother responding to that "pinned" bullsh# again.

Because you know you're wrong, or because you still don't understand how the dowel interacts with the columns that the dowel supports?

The dowel's stiffness is what supports your structure and prevents collapse due to buckling. Without the dowel, your structure collapses in a manner quite similar to the WTC.

In fact, if you compare the fire induced loss of horizontal bracing from the floor truss systems in the WTC to removing the dowel from your model by pulling it down through the bottom of the system, your model would collapse just like the WTC.

Originally Posted by Fangbeer

I don't know why you keep trying to deflect with this nonsense. I know I'm not distracted by it. We get it. You don't know how to describe the collapse with math. That's fine.

ROFL The Romans built the column almost 2000 years before the math existed but you want to ignore that and make a big deal about math. It is simple. The math makes it possible to compute the minimum required then the designers can decide on a safety factor. But if the structure is overbuilt by a considerable margin then the math is just an intellectual curiosity.

There are equations and there is data to plug into the equation.

What was the weight of all of the steel trusses and floor pans that the concrete slab was poured on? The slab was 600 tons. Though you do not find that much from anyone but me. It can be computed from the dimensions and density. But what was the weight of the steel. I don't know I have never seen it.

You talk about math but then pretend the data is irrelevant.

What were the tons of steel and concrete on every level. Gregory Urich's data is wrong. He admits he did an interpolation of the perimeter columns. Where is the data on the horizontal beams in the core? Why don't we have readable data from an official source? How much heavier did they get down the building?

TEN YEARS and all of this talk about math without demanding the data.

Can't even accurately compute the potential energy of the building without that.

psik

Originally Posted by psikeyhackr

ROFL The Romans built the column almost 2000 years before the math existed but you want to ignore that and make a big deal about math. It is simple. The math makes it possible to compute the minimum required then the designers can decide on a safety factor. But if the structure is overbuilt by a considerable margin then the math is just an intellectual curiosity.

You are missing the big picture with regards to modern construction techniques: budget. The Romans overdesigned their construction because that was the nature of the work of their day. They also weren't dealing with any overly complex structural issues either (by modern standards).

Safety factors are a minimum standard for Life Safety reasons, and, most developers, aren't going to unnessarily overdesign a spec office building for the sake of overdesigning one. Unless they want that to be their last project as a developer. It's kind of a money making venture if you haven't figured it out psikey......

It is simple. The math makes it possible to compute the minimum required then the designers can decide on a safety factor. But if the structure is overbuilt by a considerable margin then the math is just an intellectual curiosity.

Modern buildings are not "overbuilt by a considerable margin" in general, and you have not shown that the WTC was "overbuilt by a considerable margin" in specific. On the contrary, you cannot even demonstrate a working understanding of the difference between buckling and crushing modes of failure let alone how to overbuild in order to prevent them.

And what do you mean by "minimum required?" Minimum required what, exactly?

What was the weight of all of the steel trusses and floor pans that the concrete slab was poured on? The slab was 600 tons. Though you do not find that much from anyone but me. It can be computed from the dimensions and density. But what was the weight of the steel. I don't know I have never seen it.

You talk about math but then pretend the data is irrelevant.

What I'm talking about is your attempts to shoehorn a conservation of momentum model into a system that is not described by the conservation of momentum model. Math in general isn't irrelevant. It's your misapplication of math that's irrelevant. What you are witnessing in your physical model is not a collapse that is arrested by the conservation of momentum. Your collapse is arrested by the amount of force it takes to crush your paper loops. What I'm talking about is the fact that if your paper loops were slender columns they would have failed in a buckling mode, which would have taken far less force.

In the past you've shown your math to be a conservation of momentum model. What you witness in your mathematical model is a property that exists only in a closed system, and your assumption about the closed system you're trying to describe is false. Mass A impacts a more massive mass B in an inelastic collision, accelerates through a distance to impact a larger mass C and so forth. This is an attempt to show that the collapse should have slowed "enough" by the increasing mass in order for the structure of the building to arrest the collapse. What this model doesn't even bother to define is what the value of "enough" is.

What your model fails to note is that just because the product velocity of a collision between a stationary mass and an accelerating mass is less then the velocity of the accelerating mass at the moment of impact, that does not mean that the force generated by the total mass is less then the amount required to buckle the support for the stationary mass. That point is simply taken for granted by you. The trouble is, these masses are not held in place by magic, like in your mathematical model. They are held in place by a structural system that has a point of failure, and that point of failure can certainly be achieved by a mass from above falling through 1 floor worth of space.

The big problem you have is the amount of resistance that remains once the critical buckling force is reached. The answer is very little to zero. In your system, the critical buckling force is never reached. This is because your columns are pinned with a brace that makes the column very resistant to buckling. It's so resistant that the critical buckling force is much higher then the ultimate strength of the material the columns are made out of. Since this is the case, the material is crushed through the entire length of the column. Thus, your math doesn't even apply. The combined mass of upper portion of your model and the first "level" of your model do not accelerate through the space of the first level to be impacted. The entire "collapsing" mass is decelerated the entire time. This is not the case with the WTC, which was allowed to accelerate through each floor level due to the localized buckling of floor level support structure.

What were the tons of steel and concrete on every level. Gregory Urich's data is wrong. He admits he did an interpolation of the perimeter columns. Where is the data on the horizontal beams in the core? Why don't we have readable data from an official source? How much heavier did they get down the building?

The difference between the amount of force required to buckle a steel column in the WTC and to crush a steel column in the WTC is staggering. Urich showed you how the masses in the tower could be increased or decreased by more than 50% and the amount of force generated by a drop of an entire floor's worth of distance still would have exceeded capacity by an order of magnitude. But beyond that, even if you had the masses you demand, you wouldn't know what to do with them, would you Psikey? Tell me what you would do with them to determine if the building could have collapsed or not.

Originally Posted by Fangbeer

Modern buildings are not "overbuilt by a considerable margin" in general, and you have not shown that the WTC was "overbuilt by a considerable margin" in specific. On the contrary, you cannot even demonstrate a working understanding of the difference between buckling and crushing modes of failure let alone how to overbuild in order to prevent them.

And what do you mean by "minimum required?" Minimum required what, exactly?

I wasn't talking about modern buildings I was talking about that Roman column that was in the video that YOU PROVIDED THE LINK TO.

The column was built before the "modern math" was developed so they could not compute a safety factor because they could not compute the minimum strength required. That is what the math can supply.

psik

Originally Posted by psikeyhackr

I wasn't talking about modern buildings I was talking about that Roman column that was in the video that YOU PROVIDED THE LINK TO.

The column was built before the "modern math" was developed so they could not compute a safety factor because they could not compute the minimum strength required. That is what the math can supply.

psik

The Roman construction techniques were developed over centuries by trial and error, which, in a sense, was doing the math for them.