Acceleration of the falling top blocks.

[Oystein]

I have always envisaged the WTC1 & 2 collapses as 'wedge' driven. Akin to splitting a fire log with an axe. I also believe it possible that the building structure actually enabled its own collapse and guided the collapse as if on rails. Thats just me. Probably totally wrong.

If the "rails" in your image are the perimeter slabs and the core, then what you say there is pretty close to some short hand version of Major_Tom's "ROOSD"^(*) model of collapse progression. In a nutshell, he observes that the cores remained longer than the floors. that the perimeter columns peeled off in large, contiguous slabs, and that the collapse front of dust-spewing floors was contained by the perimeter, which did not itself fracture in sync with that collapse front.






(*) ROOSD is an akronym for "Run-away Open Office Space Destruction" (or similar)

 

[000063]

Thanks for this, ergo. I'm filing this in my "Shockingly Stupid and Silly Statements" file, along with this gem:



Thanks for playing!

I was looking at that yesterday, and it amazes me that in a year and a half, Ergo has learned absolutely nothing except to avoid making direct statements or actual arguments.

 

[ergo]

Thanks for this, ergo.

You're welcome.

WTC Dust has it right, of course. She explains correctly why successive collisions will disrupt, if not halt, momentum significantly and why those disruptions, especially on such large structures, will be easily visible, if the process doesn't halt altogether. We see it in pictures of structural failures in natural disasters, and in videos of failed demolitions. I'm guessing it's grade 7-level physics.

And no, making this claim does not deny the mechanics of verinage. But what occurs in verinage is vastly different, both in preparation, and in results, from what is being claimed for the Towers.

Dave Thomas claims to have an undergraduate degree in physics. If this is the case, there is no excuse for creationist-style, anti-science statements like this:

The upper sections gather mass, and fall faster and faster. The bottom sections are at rest until they are impacted and incorporated into the falling upper mass, taking on its speed.

Avalanches are also not an appropriate analogy. They are not comparable materially or behaviourally. Perhaps Ryan Mackey could explain it to you. I wonder if he's capable and/or honest enough to do so. Of course, none of you should need such an explanation. You should be able to recognize this immediately for yourselves, the difference between an avalanche and a steel and glass highrise. I genuinely don't believe the lot of you are this stupid, so I can only assume you are deliberately misleading. But in doing so, you are assuming a base level of stupidity in your intended audience, and that's insulting.

I have stated it before and I will state it again: I do not understand why Dave Thomas was invited to formal public debates on this topic.

 

[DGM]

I'm guessing it's grade 7-level physics.

Is this the same grade you learned about the "special state of mass" known as rubble?

 

[leftysergeant]

You're welcome.

WTC Dust has it right, of course. She explains correctly why successive collisions will disrupt, if not halt, momentum significantly and why those disruptions, especially on such large structures, will be easily visible, if the process doesn't halt altogether.

Hog snot. This violates conservation of number. The element which failed was the connection between the floor trusses and the perimeter columns. If the floor slab weighs X and has a failure weight of 3X and the drywall and furnishings weigh Y and three floor slabs fall on it, along with whatever portion of the drywall that is not reduced to dust and expelled from the falling rubble (let us say .2Y, for the sake of argument, since, as we shall see, the exact amount is not going to matter greatly on the next floor) the floor slab now weighs 4X+4Y-.8Y. Since this clearly excedes the fail weight of the slab by X+3.2Y, it would seem quite obvious to me that it would result in that floor's failing and dropping that weight onto the next floor, which would then weigh 5X+4Y.

Now would you care to tell me what principle would prevent this floor from falling on the next, bringing the weight of that floor to 6X+4.8Y and rinse and repeat until you run out of floor slabs?

We see it in pictures of structural failures in natural disasters, and in videos of failed demolitions.

We don't, actually. We occassionally see a structure in which insufficient pre-weakening was done or the resistance of the lower floors of the structure was underestimated.

I'm guessing it's grade 7-level physics.

No. Even a dyscalculic hose dragger can see that your arresting mechanism is unrealistic.

And no, making this claim does not deny the mechanics of verinage. But what occurs in verinage is vastly different, both in preparation, and in results, from what is being claimed for the Towers.

There is no excuse for creationist-style, anti-science statements like this. What happened to the towers differs from verinage only in the preparation. Verinage also puts a big wooden stake through your insistance that there would be an arresting mechanism and does the same with a good dollop of mashed garlic to little Dickie Gage's box dropping game. There is no arresting mechanism other than the chance that too much of the rubble will slide off the top of a really tall buillding half-way through the process of verinage.

Before you suggest it, no, the arresting mechanism is not the reason why verinage is not used on buildings over a certain height. This is just a safety consideration. If you watch an explosive demolition of a tall structure, you will see that central elements are usually blown first in order to pull the exterior of the building inward so that it will fall entirely into its footprint. (That's why people generally refer to it as an "implosion.") In verinage, an increasing amount of rubble falls over the edge as collapse procedes. That this is a danger to surrounding structures and to the equipment used to work the cables is self-evident to anyone with a room-temp IQ or better. The tallest structure of which I have seen verinage video was broken on two floors specificly to address this problem.

Avalanches are also not an appropriate analogy. They are not comparable materially or behaviourally.

Bollocks. As an avalanche progresses, it picks up more mass, thus more potential and kinetic energy, just as did the collapsing floors of the WTC. The only arresting mechanisms effecting an avalanche are changes in the slope or large intervening structures such as rocks or trees. Weren't none of those between the perimeter columns and the core columns in the WTC.

I have stated it before and I will state it again: I do not understand why Dave Thomas was invited to formal public debates on this topic.

Seems pretty obvious to me. He looks at stuff.

 

[BasqueArch]

I believe it was Bazant that discovered the two phases of global building collapse: crush-down and crush-up. Some people don’t believe these are two distinct phases.

For the first phase crush-down, the undamaged building below the failed floor is completely crushed if it satisfies his equation, in the direction of gravity.
For the second phase crush-up, at the end of the collapse, the undamaged building above the failed floor is completely crushed if it satisfies his equation, against the direction of gravity.

Here’s an example that crush-up is a different phase from crush-down:

http://www.youtube.com/watch?v=UsePUn5-88c

There is no crush-down phase because the stories below are explosively demolished
The crush-up phase fails to propagate.
The building is exploded 13 floors from the top. Top 12 stories remain standing. No or minimal crush-up propagation. The demolition contractor must have thought it was common sense that the whole building would be crushed down with relatively minimal explosives at the bottom floors only.

In most explosive demolitions, many floors, top to bottom are exploded, so there are no (undamaged) Bazant crush phases. This is global demolition is certain, but it takes much time and work. Bazant’s analysis could determine the optimum means of demolishing a building.

Is there empirical verification that crush-up does not propagate upward as crush-down continues?
In Verinage demolition, one or two floors near the middle of the building are pushed over to one side slightly askew from the structure below and the top block crushes the bottom block. I’ve only seen this done in concrete load bearing walls structures, not columns and beams structures, and the load bearing walls below hit the floors above, not at the walls above in these examples, so Bazant’s theoretical crush phases do not apply.

http://www.youtube.com/watch?v=NwFHEoiUZ7o

So there is verification crush-down and crush-up are two distinct phases . I haven’t found an example of top bearing members striking bottom bearing members in order to test the hypothesis that crush-up does not occur simultaneously with crush-down

 

[grandmastershek]

Is it me or are Dust & Ergo vaguely making the "clunkity clunk" argument?

 

[000063]

You're welcome.

WTC Dust has it right, of course. She explains correctly why successive collisions will disrupt, if not halt, momentum significantly and why those disruptions, especially on such large structures, will be easily visible, if the process doesn't halt altogether. We see it in pictures of structural failures in natural disasters, and in videos of failed demolitions. I'm guessing it's grade 7-level physics.

And no, making this claim does not deny the mechanics of verinage. But what occurs in verinage is vastly different, both in preparation, and in results, from what is being claimed for the Towers.

No, it's really not. The only real difference here is the preparation. The process is very similar, and the results are very similar. A floor failed, and the upper portion of the building fell on it with thirty times the force of its actual mass. That's over five times the total weight of the entire tower. Expecting the building to stay up under that is about as silly as saying they would not be collapsed by a moon-sized field of rubble.

Dave Thomas claims to have an undergraduate degree in physics. If this is the case, there is no excuse for creationist-style, anti-science statements like this:

And what is your physics experience? Why did you make the patently ludicrous statement that a moon-sized rubble field would not have collapsed the tower, along with the other blatantly incorrect statements which you have never recanted, such as scoffing at the sun being used to tell time, which is a concept an elementary-school student can understand?

Avalanches are also not an appropriate analogy. They are not comparable materially or behaviourally. Perhaps Ryan Mackey could explain it to you. I wonder if he's capable and/or honest enough to do so. Of course, none of you should need such an explanation. You should be able to recognize this immediately for yourselves, the difference between an avalanche and a steel and glass highrise.

That's a lot of words to avoid backing up your claim. If it's so obvious, so evident, you should be able to explain it to us bright folks very easily.

I genuinely don't believe the lot of you are this stupid, so I can only assume you are deliberately misleading.

So you are unwilling to back up your claim, are actively trying to get people who disagree with you to prove it, and are now saying that we're lying if we do not prove your claim. Oddly, you throw up this verbal chaff after DGM asks you to back up your claim in post #36. What will you get up to after breakfast, I wonder?

Odd how you constantly insult us and belittle us, including our intelligence, but suddenly, you claim not to believe we are idiots. If we're not idiots, and we disagree with you, why not consider the possibility that you are wrong?

Silly of me to think that bedunkers might actually back up their silly-ass claims.

...
In other words, most of the time, bedunkers don't even know what the argument is, or don't want to have to answer specifically, so if they find anything to link to, it's usually irrelevant or incomplete.

That's why, if you're going to make silly-ass claims, you need to be able to explain them, i.e., back them up, in your own words, so we can hold you to some standard of factuality. Most of you don't.

Ergo, you have once again demonstrated that you are a brazen, sophist lying hypocrite. If you would like to prove me wrong, all it takes is to explain your claims instead of demanding others do so.

But in doing so, you are assuming a base level of stupidity in your intended audience, and that's insulting.

Sometimes I wonder.

I have stated it before and I will state it again: I do not understand why Dave Thomas was invited to formal public debates on this topic.

We've already established that there are many things you don't understand, Ergo. No need to elaborate.

Is it me or are Dust & Ergo vaguely making the "clunkity clunk" argument?

I don't think he's really making any argument at all, only unbacked claims.

 

[DaveThomasNMSR]

...
Dave Thomas claims to have an undergraduate degree in physics. If this is the case, there is no excuse for creationist-style, anti-science statements like this: ...

Avalanches are also not an appropriate analogy. They are not comparable materially or behaviourally. Perhaps Ryan Mackey could explain it to you. I wonder if he's capable and/or honest enough to do so. Of course, none of you should need such an explanation. You should be able to recognize this immediately for yourselves, the difference between an avalanche and a steel and glass highrise. I genuinely don't believe the lot of you are this stupid, so I can only assume you are deliberately misleading. But in doing so, you are assuming a base level of stupidity in your intended audience, and that's insulting.

I have stated it before and I will state it again: I do not understand why Dave Thomas was invited to formal public debates on this topic.

Big news, ergo!!

I suggest you submit your paper on how the "Law of Conservation of Momentum" is all wrong right away.

Let us know when you get your Nobel.

It might be a while, though - real science requires a little more effort than simply invoking the Appeal to Ridicule.

 

[leftysergeant]

Is it me or are Dust & Ergo vaguely making the "clunkity clunk" argument?

They are dancing to the rythm of the maraca resting on top of Sophia's spinal column.

 

[000063]

Big news, ergo!!

I suggest you submit your paper on how the "Law of Conservation of Momentum" is all wrong right away.

Let us know when you get your Nobel.

It might be a while, though - real science requires a little more effort than simply invoking the Appeal to Ridicule.

Give him some credit for originality, though; I've never heard someone try and say their opponents are lying and that their opponents should prove the claim they don't believe before. I'm not sure there's even a name for that fallacy, other than Attempting to Shift the Burden of Proof, albeit in the most bizarre fashion possible.

I'd ask Ergo, like I asked Chris7, if "misleading statements" are the same as lying, but Ergo has me on ignore because I kept pointing out his patterns and poking holes in his arguments. And it's not like either of them are ever going to answer, anyway.

 

[Carlos]

WTC Dust and Ergo

The top towenty-one floors hit the floor below with some amount of energy, and part of this energy is used to cause the floor below structure to fail.

So, once the floor below structure fails and becomes unable to support the twenty-one floors mass, what do you think would happen with the remaining energy?

 

[000063]

It gets turned to rubble. Since matter is energy, and rubble is a special type of mass, then it can't damage the building.

Duh.

Of course, Ergo doesn't like to respond to direct contradictions of him, and will no doubt return sneering at us for not supporting his argument, which he claims we're lying making "misleading statements" about and know is true.

I'm not sure when he added long-range mind-reading to his repertoire.

 

[WTC Dust]

I emphasized that I wanted to talk about acceleration, which is
the change in velocity. How could you miss this?

The gravity collapse model forces certain things. It's what a model
does. Gravity is said to have accelerated the floors of the building
downward, where they impacted lower floors.

Acceleration takes time, which means that things don't actually
get going very fast in a twelve foot fall, which was the distance
between the floors of the WTC.

If you believe the gravity collapse model, you have to add up all
those twelve foot falling times. It's way off. Not even close.
Which disproves the gravity collapse model in its pure form.
Gravity didn't change. Gravity didn't go away. It just wasn't
the destructive force.

The exact numbers don't matter. What matters is that falling things accelerate. They don't fall at a static velocity, as you appear to believe.

 

[WTC Dust]

This is a serious misunderstanding of the gravity collapse model.
Floor 80 doesn't begin to fall until floors 81-110 reach it (taking
0.75 seconds, at a minimum). Then, floors 80-110 begin to
fall and take 0.75 seconds to reach floor 79. You can't fall
faster than that on Earth, if the only force is gravity.

The gravity collapse model is faulty. I'm simply taking it seriously
for the purposes of this discussion.

Wrong, wrong, wrong. The upper sections gather mass, and fall faster and faster. The bottom sections are at rest until they are impacted and incorporated into the falling upper mass, taking on its speed.

In your weird world, an avalanche would not gather speed as it flows downhill, it would just poke along at constant velocity.

Wrong.

You're welcome.

 

[WTC Dust]

Interesting. What was the fuel of this fire?

This all moot given a controlled demolition would not do what you saw on 9/11.

Controlled demolitions ARE gravity driven after all. Controlled demolitions do NOT blow up buildings, but only use explosives to unsupport enough of the building to allow gravity to distroy the structure. On 9/11 it was fire that did the unsupporting.

 

[WTC Dust]

Part of the gravity-only collapse model is that the upper floors
crashing into lower floors is what dislodged them.
Now you have unzipping of perimeter columns.

Muddled thinking.

Nice to know you are still alive and well, but a bummer that you still haven't figured this out.

You do not have to wait for one floor to hit the next if the perimeter columns are unzipping, as we can see that they do in most of the close-up video. You also ignore the fact that falling fluid will continue to exert a downward force at least equal to gravity in all directions except straight up, and that compressed air can actually add more energy to the reaction because it allows a loosely-packed mass to continue accelerating downward without totally stopping with each impact, even if at slightly less than g. Thus, the need to overcome resistance in the structure below would slow collapse, but not arrest it.

The whole process took closer to twenty than to ten seconds in both towers. There is no need for a magic space-case discombobulator gun or demolition charges.

 

[WTC Dust]

I say that in real life, the floor would have provided some resistance
to any global collapse, and that it would be slowed.

If twenty floors of the WTC became detached and fell twelve feet
onto the next lower floor, I'd have expected some damage to the
floor, but it would have held.

Twelve feet doesn't give you a lot of time to accelerate, so the
upper floors wouldn't have had that much kinetic energy.

WTC Dust and Ergo

The top towenty-one floors hit the floor below with some amount of energy, and part of this energy is used to cause the floor below structure to fail.

So, once the floor below structure fails and becomes unable to support the twenty-one floors mass, what do you think would happen with the remaining energy?

 

[MarkLindeman]

This is a serious misunderstanding of the gravity collapse model.
Floor 80 doesn't begin to fall until floors 81-110 reach it (taking
0.75 seconds, at a minimum). Then, floors 80-110 begin to
fall and take 0.75 seconds to reach floor 79. You can't fall
faster than that on Earth, if the only force is gravity.

Gravity is not the only force. Floors 81-110 do not merely "reach" floor 80, they collide with floor 80. (Actually there are multiple collisions.)

Not sure how you are missing this.

 

[WTC Dust]

If you saw the beginning of an avalanche 1/4 mile high, and ten
seconds later, the very top rocks were already at your feet, you
could conclude that something other than gravity caused the
rocks to fall.

Rocks lower down on the mountain would have slowed the
upper rocks.

Wrong, wrong, wrong. The upper sections gather mass, and fall faster and faster. The bottom sections are at rest until they are impacted and incorporated into the falling upper mass, taking on its speed.

In your weird world, an avalanche would not gather speed as it flows downhill, it would just poke along at constant velocity.

Wrong.

You're welcome.