Why a one-way Crush down is not possible

[Tony Szamboti]

But there was a 'velocity loss' relative to free-fall in air. Nobody denies that. It's measurable to a reasonable degree in the early stages of collapse. But it was gradual and caused by many small chaotic impacts.

Your statement above makes no sense. It is based solely on your belief that there must be a Bazantian/Rossian jolt. Plus that you cannot handle any explanation that copes happily with an absence of it. You are utterly jolt-obsessed.

But that's because you poured your ego into 'publishing' a crap paper. You have become single-issue fundamentalist.

There was never a velocity loss. After the upper block starts falling there was only 10% of the original resistance by the 300% stronger than static load columns which kept the acceleration to 0.7g. That isn't velocity loss which requires deceleration.

The velocity loss required isn't relative to free-fall in air.

You are confused if you think it is.

 

[R.Mackey]

There was never a velocity loss. After the upper block starts falling there was only 10% of the original resistance by the 300% stronger than static load columns which kept the acceleration to 0.7g. That isn't velocity loss which requires deceleration.

The velocity loss required isn't relative to free-fall in air.

You are confused if you think it is.

Okay, this is so obviously wrong that I'm jumping ahead.

You're saying that the "300% stronger than static load columns" -- which is also wrong -- resisted at the same strength, through the entire length of the collapse.

That's wrong. They fail after about 3% strain, best case, after which their strength is zero.

300% x 3% = 9%, and if you add to that the energy sink from conservation of momentum, you get the right answer.

My god, man. You have even less idea what you're doing than I thought.

 

[Tony Szamboti]

Prove it. Show me where Dr. Bazant claims this.

Read the Adendum to Bazant's 2002 paper.

It does nothing of the kind. In your whitepaper, you curve-fit to find an average acceleration of 22.8 feet per second² in the first three seconds of descent. That leaves about 9 feet per second² average deceleration caused by destruction of the lower structure. This is consistent with the findings of the BLGB paper.

There isn't much curve fitting necessary as the R**2 value of the least squares fit is .9961.

Read what I said to GlennB concerning the remaining resistance as you seem confused here also.

In your own paper, your entire energy cost argument is based upon a "spring constant" which is never calculated nor referenced, but is merely stated. As a result, your estimate for destructive energy is about four times higher than all other published estimates. There's no reason why I should accept this.

You will find the axial spring constant or stiffness of the columns in the towers calculated in Appendix C of the Missing Jolt paper. Why haven't you noticed that? The energy of deformation estimate we make in the paper in Appendix D is based on the elastic deformation, the plastic deformation, and the classes of the columns and their ability to sustain a plastic moment in buckling. If you think it is inaccurate please show why. Don't just make a claim that it is higher than others have estimated.

Again, see BLGB, 2008. And I note you still won't accept that there is no "jolt." You've denied saying it, you've claimed it was Dr. Bazant's claim, and you've tried the Truther Shuffle to retreat from it. Won't work. Own up to the smoothness of the collapse first, and once that's settled, we can talk energetics.

However unlikely your scenario of no observable jolt being necessary, your sceario is still shown to be non-explanatory due to the lack of velocity loss necessitated due to the kinetic energy losses needed by the energy of deformation.

ETA: Oh, one more thing -- your own paper, warts and all, does not predict the collapse would stop were it not for "Explosives." It merely predicts that the collapse would be slower. Ergo, in your little world, the "Explosives" weren't even needed to bring the structure down. So, why were they there? Why should I believe a word of it?

If you noticed at the bottom of page 10 we state

"It should also be noted that the energy losses and conservation of momentum we have calculated and used here, to determine the velocity loss, are a minimum. We do not consider energy losses due to vibration of the building, heat, and sound, during the initiating impulse, all of which would have required energy from the impulse to produce and thus have an additional effect on velocity loss.

This would also apply to your theoretical multitude of smaller impulses. The fact that 76% of the energy of the upper block is drained by just the deformation of the columns on either side of the first two colliding floors implies that had the other significant energy sinks been considered, the total would most probably show the collapse would arrest.

Mackey, you really need to at least attempt show some figures and calculations to back up what you are claiming. Your position has no credibility without it.

 

[twinstead]

Mackey, you really need to at least attempt show some figures and calculations to back up what you are claiming. Your position has no credibility without it.

The irony. It burns.

 

[Tony Szamboti]

Okay, this is so obviously wrong that I'm jumping ahead.

You're saying that the "300% stronger than static load columns" -- which is also wrong -- resisted at the same strength, through the entire length of the collapse.

That's wrong. They fail after about 3% strain, best case, after which their strength is zero.

300% x 3% = 9%, and if you add to that the energy sink from conservation of momentum, you get the right answer.

My god, man. You have even less idea what you're doing than I thought.

I am talking about 300% stronger than the static load at just yield. You won't even be anywhere near 3% strain at yield. The load needed to get to 3% strain is significantly higher than 300% of the static load.

You are really confused. Or is it just that you want to confuse things here?

Mackey, if you feel this strongly about this write a rebuttal to the paper to which I can respond. I am done talking to you about it until you do so. Show your numbers in a full discussion.

 

[R.Mackey]

Read the Adendum to Bazant's 2002 paper.

I have. It doesn't say that. Looks like you lied again, chum.

You will find the axial spring constant or stiffness of the columns in the towers calculated in Appendix C of the Missing Jolt paper. Why haven't you noticed that? The energy of deformation estimate we make in the paper in Appendix D is based on the elastic deformation, the plastic deformation, and the classes of the columns and their ability to sustain a plastic moment in buckling. If you think it is inaccurate please show why. Don't just make a claim that it is higher than others have estimated.

Thanks for clarifying that. Now that I know what you did, I am absolutely certain your calculation is complete idiocy. You are calculating the spring constant of the entire 110-story stack, assuming "average dimensions" at the 55th story, to compute a single overall spring constant -- and then applying that constant at the impact floors.

Nonsense. The actual behavior will be of a series of coupled springs, where the spring constant varies radically with height. At the collapse zone, the 97th and 98th floors, the actual spring constant will be considerably lower, as the steel is considerably thinner.

As a result, you grossly overestimated the absorption by structure, and you did so because you applied a totally inane method of estimation. Fail, Tony.

However unlikely your scenario of no observable jolt being necessary, your sceario is still shown to be non-explanatory due to the lack of velocity loss necessitated due to the kinetic energy losses needed by the energy of deformation.

So you still fail to recognize that the collapse is smooth, and there's no "jolt."

Figures.

If you noticed at the bottom of page 10 we state

"It should also be noted that the energy losses and conservation of momentum we have calculated and used here, to determine the velocity loss, are a minimum. We do not consider energy losses due to vibration of the building, heat, and sound, during the initiating impulse, all of which would have required energy from the impulse to produce and thus have an additional effect on velocity loss.

This would also apply to your theoretical multitude of smaller impulses. The fact that 76% of the energy of the upper block is drained by just the deformation of the columns on either side of the first two colliding floors implies that had the other significant energy sinks been considered, the total would most probably show the collapse would arrest.

So, in other words, you can't calculate that the collapse would arrest, even by artificially inflating your energy sinks, but it's "only" 24% so you just handwave it away as trivial.

That's called Destroying the Exception, Tony. Classic fallacy.

Mackey, you really need to at least attempt show some figures and calculations to back up what you are claiming. Your position has no credibility without it.

There are, once again, a multitude of published and accepted papers that demonstrate it. I don't need to rederive these papers to prove you're wrong. The burden of proof is on your side, and all I'm getting from you is double-talk.

I am talking about 300% stronger than the static load at just yield. You won't even be anywhere near 3% strain at yield. The load needed to get to 3% strain is significantly higher than 300% of the static load.

You write the above, and then you write this..?

You are really confused. Or is it just that you want to confuse things here?

What do you think "yield" means, Tony? That's the highest stress that member will ever see. At yield it deforms. So you're saying "the load needed to get to 3% strain is significantly higher than 300% of the static load" -- so the structure had more than a safety factor of 3 built in?

Who's confused, again?

Also irrelevant. Again, what you wrote was you trying to apply the static strength over an entire range of motion. That's cherry-picking. You're applying the maximum strength, as-built, and then assuming that it won't weaken at all even after it buckles, even after it snaps, all the way to the ground. Complete lunacy.

Mackey, if you feel this strongly about this write a rebuttal to the paper to which I can respond. I am done talking to you about it until you do so. Show your numbers in a full discussion.

Emphasis added. Originally I laughed at this, but then I realized that if I read the above literally, you're in fact saying that you can't respond to my rebuttals, and you're going quiet until I dumb it down enough that you can...

So, to recap:

• You lied about the tilting of the upper block
• You lied about saying that it wasn't tilted
• You claimed the tilt was not "germane" and focused on energy absorption
• You lie and say Dr. Bazant also says that without a "jolt" the collapse could not occur "naturally," viz. without explosives
• You suggest that the static strength of the lower structure can be multiplied by the distance of collapse to get the true energy absorption
• You call attention to your whitepaper, in which the above is not claimed, but instead you treat the columns as uniform springs, thereby vastly overestimating the energy sink on the collapse floors
• You whine about me producing numbers, ignorant of the fact that you are indeed challenging a published, quantified result

ETA: Oh, one more I forgot:

• When backed against the wall, you suggest that I am "wittingly" part of the coverup

You're not doing well, Tony. Even you must realize this.

 

[Grizzly Bear]

EDIT: disregard

 

[AZCat]

Wow. I see Tony Szamboti is still struggling with concepts he should have mastered back as an undergraduate. Have you no integrity, Tony? Admit you're in over your head and concede.

 

[R.Mackey]

That'll be the day.

And perhaps later we can work on the idea that the heating etc. in his "additional 24%" handwave comes out of the energy lost by the inelastic collision, rather than another brand-new energy sink. Looks like we can add Tony to Gordon Ross and femr2 and the others who don't understand conservation of energy...

... but I'm trying to work on his confusion one item at a time, so he at least has a chance. Naturally, he's not cooperating. They never do.

 

[Tony Szamboti]

What do you think "yield" means, Tony? That's the highest stress that member will ever see. At yield it deforms. So you're saying "the load needed to get to 3% strain is significantly higher than 300% of the static load" -- so the structure had more than a safety factor of 3 built in?

Who's confused, again?

You are either an idiot, which I doubt, or you are trying to confuse those who can't think enough for themselves in this type of discussion.

Yield is well below 3% strain. That is why we use the 0.2% strain as the yield point. The factor of safety is based on yield strength in a structure not ultimate. If you are thinking ultimate then, yes the factor of safety for ultimate failure was greater than 300%.

 

[R.Mackey]

Except we're talking about buckling behavior here.

If it was linear strain, then you're correct, the ultimate strength would be about 40% higher. But in a buckling situation, once you start going plastic in compression as well, buckling is immediate.

Think, Tony. And work on the multitude of other problems. Don't just nitpick and shuffle. Start with understanding why there's no jolt.

 

[Tony Szamboti]

Wow. I see Tony Szamboti is still struggling with concepts he should have mastered back as an undergraduate. Have you no integrity, Tony? Admit you're in over your head and concede.

AZCat, so it seems you are continuing your attempts at unsupported ridicule of anyone questioning the present official explanation of the collapses of those buildings.

I haven't seen you do anything but. Is this all you are capable of?

What do you think I get wrong? C'mon, don't shy away because someone is asking you a technical question.

 

[Hokulele]

Start with understanding why there's no jolt. there should not have been any jolt.

Fixed that for you.

 

[Tony Szamboti]

Except we're talking about buckling behavior here.

If it was linear strain, then you're correct, the ultimate strength would be about 40% higher. But in a buckling situation, once you start going plastic in compression as well, buckling is immediate.

Think, Tony. And work on the multitude of other problems. Don't just nitpick and shuffle. Start with understanding why there's no jolt.

After yield there is an axial plastic deformation phase before prior to buckling.

 

[R.Mackey]

Judges also would have accepted "start with understanding the correct reason why there's no jolt," but a little extra clarity never hurt.

 

[AZCat]

I wouldn't suggest stressing Tony any further today by discussing the "source" of the "additional" energy - the strain might be too much for him.

Engineers like Tony make me sad. I don't know how they derived so little knowledge from school and experience compared to the rest of us, but it must be frustrating for them to have spent a comparable amount of time on subjects yet to have gained so much less. I'm no paragon of engineering, but even this stuff is obvious to me (after a little reflection, of course).

 

[R.Mackey]

After yield there is an axial plastic deformation phase before prior to buckling.

Only for very low slenderness ratios. Otherwise the plastic deformation is a geometric one, not actual bulk plasticity in the materials.

Not relevant for this problem. Keep on tapdancing, Tony.

 

[Grizzly Bear]

What do you think I get wrong? C'mon, don't shy away because someone is asking you a technical question.

Is there really a need to ask that question Tony? We're covering material I studied not too long ago... this is undergraduate material in both areas majoring architecture and engineering. This is material I covered in my 2nd and 3rd year

 

[Tony Szamboti]

Judges also would have accepted "start with understanding the correct reason why there's no jolt," but a little extra clarity never hurt.

Where are your numbers Mackey for your no jolt scenario and your explanation of why no velocity loss would be observable?

You obviously can't produce numbers to back up those claims and you must continue to obfuscate to maintain your position.

I have other things to do besides argue with the likes of you.

 

[AZCat]

AZCat, so it seems you are continuing your attempts at unsupported ridicule of anyone questioning the present official explanation of the collapses of those buildings.

I haven't seen you do anything but. Is this all you are capable of?

What do you think I get wrong? C'mon, don't shy away because someone is asking you a technical question.

That's funny - I seem to remember you doing the exact same thing when I asked you technical questions at DU and here. Lying isn't good practice for an engineer, Tony - what would your state board think of such behavior?