9/11 No Longer Matters

Was there any math involved? Psik seems to think physics doesn't give a (*)(*)(*)(*) about math whereas I content we understand and express physics through math. Just curious how they do it in the big schools. Do they just tell you how physics "is" and leave it at that?

 

Physics is part of the Philosophy Department.

QED

 

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

 

Chicken or egg psikey? You're attempting to divide things that are indivisible.

With that in mind, it's about time you divided by zero.

 

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

Ask Darwin.

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?

 

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

 

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 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.

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

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 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.

They can't build something that cannot be built.

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

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...

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

 

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.

 

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

 

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......

 

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 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.

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.

 

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.

 

The math was there, even in the roman time. What they lacked was a notation system for said math. The notation system that we use today was developped AFTER the formula were created. In fact we have old text prior to "modern" notation where everything is written down as full length text without any of the known math symbol that we are using today and without algebraic formula, which came also later. But the math was there, it always was.

 

Wrong, physics isn't related to math, or so we've been told.

Maybe psikey has been committing a typo and meant to write psychics.

 

Some people are apparently unable to understand the principal that was taught using the Roman column as an example. The point was not how over-engineered the column was. The point was to illustrate the properties of a column, and the manner in which a column functions. The shape of the columns in your model determines the properties of the columns. Yours are short, with most of the material positioned far from the centroid. This makes them very resistant to buckling. The columns in the WTC were not this shape. They were much more susceptible, in scale, to a buckling mode of failure. The video I posted was posted to provide an understanding of why this is the case.

 

Seriously, he doesn't understand why the dowel is important in his model. Do you think the importance of a column's relative proportion is going to phase him one bit?

 

It's a good thing that engineering certifications are a little more intensive then dicking around with toy rockets in high school, and rooming with an architect buddy.

 

Very resistant to buckling in comparison to WHAT?

I keep telling you that they were deliberately tested to be AS WEAK AS POSSIBLE in comparison to the weight they were holding. It was tested empirically. I made repeated tests to see how many washers were needed to collapse a single loop. It took a minimum of 12 and a maximum of 15. That is why there are 11 single loops at the top of the stack. And I left the structure standing for three days.

The amount of energy required to flatten a loop was also tested empirically. It was 4 washers dropped form 4 or 5 inches. I don't recall now but it came to 0.118 joules. So the distance of empty space gave my dropped 4 washers enough energy to flatten 8 loops. The drop damaged 9 loops but some were only partially damaged, not completely flattened.

My point is that physics is incapable of giving a (*)(*)(*)(*) about math. It is inanimate! The math is the result of the observation of physics which eventually provided predictive ability. The Romans did not have the math but they were able to build the column anyway. The math makes it possible to compute how much overkill the Romans built into the column without being able to compute it themselves.

psik

 

In comparison to the exact same mass of material configured in a different shape. The exact same mass of material can be made to behave very differently based on the shape of the material.

And I keep telling you that this premise is false. They are not as weak as possible and they do not model the failure of the WTC because your columns are configured to fail in a crushing mode rather than a buckling mode. You've created a system in which the ultimate strength of the material is less then the critical buckling force of the column. Columns that are "as weak as possible" can fail using much less force then the ultimate strength of the material due to buckling instability.

Your columns can't buckle, therefore they are inherently as strong a shape as they can possibly be. Your argument that you've loaded the columns with a mass that approaches the ultimate strength of the material, does not mean you've made a column that is as weak as possible. Beyond the ultimate strength of your materials, in thinking about your structure more, your cylinder shaped columns are also strengthened by the resistance of air pressure. As the column fails, the air inside the column is compressed and this takes energy too.

Why are there not 4 or 5 inches between "levels" then? If collapse initiation was caused by the upper portion falling through 1 level of space, shouldn't all your levels of space be equidistant?

And our point is that you don't understand the principals you are attempting to model. That's not the fault of physics, math or physicists. That's your fault.

The math is a language that helps to describe these principals. If you don't understand, or are incapable of understanding the language of physics, how could you possible understand or be capable of understanding the phenomenon you are observing?

 

Exactly! You are talking about the mass of the paper loops while saying nothing about the mass of the washers they support. It isn't the dynamic load of paper loops that is causing them to be crushed in the collapse.

You are just producing debating blather. Debating Newtonian physics is absurd. It can only influence people who don't understand it anyway.

psik

 

?

You didn't understand a word of what I said, did you?

You said your columns are as weak as possible to support the mass that they support. They aren't. What part of this are you having trouble with?

 

I am the one who did the test. How would you know? And what would the shape have to do with it. I tested THAT SHAPE to destruction.

psik