Bazant was right!! Imagine that

[twinstead]

Well, this layperson just comes with a case of beer and some pizza. Anybody hungry?

 

[Dave Rogers]

Part A? Part C? Somebody has been reading Heiwa's bull. That's your problem right there.

Not necessarily. It's Bazant's notation, from back before Heiwa started polluting the waters of intelligent discourse. In fact, the very choice of A and C for the two parts should be rather an obvious hint that they are not the only relevant entities here; anyone whose brain isn't on standby should immediately ask themself, "OK, so what's part B?"

Dave

 

[DGM]

Not necessarily. It's Bazant's notation, from back before Heiwa started polluting the waters of intelligent discourse. In fact, the very choice of A and C for the two parts should be rather an obvious hint that they are not the only relevant entities here; anyone whose brain isn't on standby should immediately ask themself, "OK, so what's part B?"

Dave

I didn't look at it that way. I suppose part "B" would be what I described as part "C"(upper) increasing in mass and density. The collapse front.

 

[Horatius]

Yes i see that in the video the upper portion of floors in the building seems to have just as many floors in the lower portion of the building and that when the supports are removed upper part C crushes Lower Part A, and both blocks seem to be destroying each other at the same rate, i assume they started the collapse initaiation in the middle of the building for this very reason and i assume that if they tried to initiate the collapse 3/4 of the way up the building instead of in the middle the top upper part C would dissapear before it completely crushed lower part A and leave about 1/4 of the building standing is that right?

Actually, surprisingly, it isn't right. Take a look at this video, which is a compilation of several of these demolitions:




In particular, note the ones at about the 2:30 and 3:20 marks. At 2:30, we see one where the upper block is about 1/3 (or maybe a bit more) of the building. More dramatically, in the one at 3:20, the upper block looks to be less than 1/4 of the whole building. Yet, the collapse continues all the way to the ground.

I dont understand why the top section upper part C of the towers when it impacts lower part A of the towers doesnt disintegrate at the same rate it is destroying the lower part C of the towers, so why does it appear that the upper part C of the towers is much more solid that Lower part A wouldnt the upper part C have to be more solid to survive crushing 90 lower floors without disentegrating completely before it reached the bottom?

So how did upper part C survive all the way to the bottom without disintegrating to pieces, i am a computer technician i fix and repair computers part time i am not a structural enginner, so please explain in laymans terms thankyou?

This is part of the problem here. It's hard to explain it in layman's terms, as it is both really complicated, and very counterintuitive. I can understand being confused by such collapses, as we're used to thinking of buildings as being very strong, and to see such complete disintegration is shocking. That "counterintuitive" part is why we always insist on people doing calculations, and backing up those calculations with experiments, as much as is practical.

As another example, going back to the issue of the upper block crushing the lower block, and why it appears to be so much stronger. I'd be very surprised if anyone could give a simple calculation that would explain that, but if we look at the examples in the video above, that is, in fact, what seems to happen in most (but not all!) cases, counterintuitive as that may be. But even that is not the most counterintuitive thing we see in that video. Take a look at the example at time 2:00. In this case we see an example where the upper block does seem to "crush up" before the lower block is completely "crushed down", and yet, the "crush down" continues all the way to the ground, anyways. And that's with some very obvious "mass shedding" on the side facing the camera!

So, yes, it's counterintuitive. I understand being confused by it. But when you follow the math, and then really look at the real-world examples we have available, it seems as if the counterintuitive conclusions of the calculations are in fact correct. When our expectations are so clearly at odds with the real world, a reasonable person must accept that their expectations are just wrong, even if that makes your brain hurt.

 

[Newtons Bit]

Not necessarily. It's Bazant's notation, from back before Heiwa started polluting the waters of intelligent discourse. In fact, the very choice of A and C for the two parts should be rather an obvious hint that they are not the only relevant entities here; anyone whose brain isn't on standby should immediately ask themself, "OK, so what's part B?"

Dave

I don't see it in the Bazant and Zhou paper. Is it in the second one?

 

[Dave Rogers]

I don't see it in the Bazant and Zhou paper. Is it in the second one?

Damn, I may have to look this up - I think it was Bazant and Verdure. The whole point is that part B is the mass of rubble between A and C, which is the part (or rather, the part whose interactions with the other parts) that Heiwa and lots of other conspiracists like to ignore.

Dave

 

[alienentity]

Yes i see that in the video the upper portion of floors in the building seems
to have just as many floors in the lower portion of the building and that
when the supports are removed upper part C crushes Lower Part A, and
both blocks seem to be destroying each other at the same rate,
<snip>

To add to what Horatius wrote, I've carefully counted the floors of those videos to answer the same question and found most of them are about 50/50.
So I don't really agree with Horatius on that point.

As to C vs A, B is the compacted rubble which accumulates - the collapse front. B increases in both mass and velocity, obviously. This is one point completely missed by almost all truthers. I'll get back to that.
The other point usually missed is that B always precedes C, so as the collapse progresses, a lot of the 'work' is being done by this collapse rubble, before the upper block passes thru that space.
Conversely, from the POV of A, it isn't meeting C intact, since B has already passed thru and done much of the work.

Supposing your initial impression operates on the 110 story WTC towers. In that case you have an initial upper block mass of about 13% the overall height of the building. If, as you theorize, both upper and lower sections are destroyed at the same rate, then at a point roughly 26% down, both sections are converted to rubble - this rubble is far more dense than the original structure, and has now accelerated and accumulated.

So now you have a mass representing some 30 floors, falling even faster than the initial 1 or two stories which initiated the collapse!

Let's say Ci (initial) = h(15 stories)v (initial velocity)
So at the 26% point Cf (final) = h (26 stories) v (final velocity)

I'm just creating a crude equation to demonstrate the basic difference in force. It's very easy to see that Cf is far greater than Ci, so if Ci was sufficient to cause collapse, Cf is even more sufficient.

It doesn't matter whether or not the upper block is now completely crushed into rubble.

Another way to express it is that the upper block is really CB with B growing constantly.

 

[Horatius]

To add to what Horatius wrote, I've carefully counted the floors of those videos to answer the same question and found most of them are about 50/50.
So I don't really agree with Horatius on that point.

The one at 3:20 is much less than 50%. There are 3 stories above the two they collapse to start the demolition, and I counted about 13 stories in total. In one frame, you can count 7 or 8 stories from the top, and they pan down from there as the demolition progresses. The others are all close to 50%, but the dropping block is usually a bit less than 50%, from what I can tell. One seemed to be 6 stories out of about 14, and another 6 stories out of about 15.

We really need better camera work on these things!

 

[DGM]

We really need better camera work on these things!

Jesh..... It's hard enough to edit out the explosions and squibs.

 

[Horatius]

Jesh..... It's hard enough to edit out the explosions and squibs.

This is why I'm advocating that all new high-rise buildings be constructed as holograms right from the beginning.

 

[TruthersLie]

Yes i see that in the video the upper portion of floors in the building seems
to have just as many floors in the lower portion of the building and that
when the supports are removed upper part C crushes Lower Part A, and
both blocks seem to be destroying each other at the same rate, i assume
they started the collapse initaiation in the middle of the building for this very
reason and i assume that if they tried to initiate the collapse 3/4 of the way
up the building instead of in the middle the top upper part C would dissapear
before it completely crushed lower part A and leave about 1/4 of the building
standing is that right?

In that particular video of verinage, you are correct. There is also another one where you have the upper 4 floors crush down the lower 12 floors. Look them up.

Nice try, but incorrect.

I dont understand why the top section upper part C of the towers when it impacts
lower part A of the towers doesnt disintegrate at the same rate it is destroying the
lower part C of the towers, so why does it appear that the upper part C of the towers
is much more solid that Lower part A wouldnt the upper part C have to be more solid
to survive crushing 90 lower floors without disentegrating completely before it reached the bottom?

1. we cannot see through the smoke and debris to see that it was fully intact before hitting the ground so your assertion is not proven.
2. it doesn't matter whether it was solid or rubble, once that MASS was started it would continue (whether it stayed together or in pieces) Where would that mass have gone? Oh downwards with gravity. Which is what bazant showed in his limiting case.

So how did upper part C survive all the way to the bottom without disintegrating
to pieces,

For the towers we cannot see if it survived all the way to the ground. So it is not really a valid question. But your wording is very poor.

nothing "disintegrated." YOu had a building collapsing and turning into rubble. That rubble still had mass and velocity. Where does it all go? straight down with gravity.

 

[rwguinn]

Welcome

Even if the top part is "broken to pieces" it still contains the same mass it started with plus the added mass of all the floors it crushed on the way. The upper part is in fact getting denser not weaker. Laymen enough?

yup...

Part A? Part C? Somebody has been reading Heiwa's bull. That's your problem right there.

Reading it? uh, huh...

As Newtons Bit notes, I don't think thecritta is just any layperson. It sure appears he has come with an agenda.

yup

 

[Travis]

The upper block was mostly obscured by smoke and dust as it fell. Where are these notions that it survived intact until it hit the ground coming from?

 

[Horatius]

The upper block was mostly obscured by smoke and dust as it fell. Where are these notions that it survived intact until it hit the ground coming from?

Persistent mis-readings of Bazant, apparently.

 

[Travis]

Persistent mis-readings of Bazant, apparently.

That wouldn't surprise me.

 

[bardamu]

Even if the top part is "broken to pieces" it still contains the same mass it started with plus the added mass of all the floors it crushed on the way. The upper part is in fact getting denser not weaker. Laymen enough?

Imagine an old-fashioned bale of straw about 4ft long. You cut the strings and the bale falls apart into 3 or 4 inch flakes, which you can easily throw into your cow stalls. Now suppose you were walking past the barn just when Leroy decides to throw a bale of straw off the top of the stack. Would you rather be hit on the head by a bale that's had its strings cut or a bale that's still compressed into one solid mass?

As Newtons Bit notes, I don't think thecritta is just any layperson. It sure appears he has come with an agenda.

It appears his agenda is to discuss 9/11 conspiracy theories in a friendly and lively way.

 

[NoZed Avenger]

Imagine an old-fashioned bale of straw about 4ft long. You cut the strings and the bale falls apart into 3 or 4 inch flakes, which you can easily throw into your cow stalls. Now suppose you were walking past the barn just when Leroy decides to throw a bale of straw off the top of the stack. Would you rather be hit on the head by a bale that's had its strings cut or a bale that's still compressed into one solid mass?

Straw does not behave the same way as chunks of concrete and steel.

Concrete is not "compressed" into a bale in a building.

You might as well use pizza boxes to model the collapse.

 

[DGM]

Imagine an old-fashioned bale of straw about 4ft long. You cut the strings and the bale falls apart into 3 or 4 inch flakes, which you can easily throw into your cow stalls. Now suppose you were walking past the barn just when Leroy decides to throw a bale of straw off the top of the stack. Would you rather be hit on the head by a bale that's had its strings cut or a bale that's still compressed into one solid mass?

.

I can imagine that (with hay). Now tell me how this applies to the WTC?

 

[BigAl]

Imagine an old-fashioned bale of straw about 4ft long. You cut the strings and the bale falls apart into 3 or 4 inch flakes, which you can easily throw into your cow stalls. Now suppose you were walking past the barn just when Leroy decides to throw a bale of straw off the top of the stack. Would you rather be hit on the head by a bale that's had its strings cut or a bale that's still compressed into one solid mass?

If the bale is going 500MPH. cut strings or not, it wouldn't make any difference.

 

[A W Smith]

How bout a little fire scarecrow?

Imagine an old-fashioned bale of straw about 4ft long. You cut the strings and the bale falls apart into 3 or 4 inch flakes, which you can easily throw into your cow stalls. Now suppose you were walking past the barn just when Leroy decides to throw a bale of straw off the top of the stack. Would you rather be hit on the head by a bale that's had its strings cut or a bale that's still compressed into one solid mass?
.

Perfect example of a straw man logical fallacy