newton3376
The Truth Movement.....still not at 1%
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Who knew they were copyrighted?
Moderated Continuation - Why a one-way Crush down is not possible
- Thread starter Cuddles
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- wtc collapse
Who knew they were copyrighted?
According Bazant in several papers; a part C (upper structural assembly of WTC 1) will one-way crush down part A (lower structural assembly of WTC 1), when intermediate supports between parts C and A are removed. For this to happen, Bazant assumes that part C is rigid and part A is not.
If, on the other hand, you simply assume that part A is rigid and part C is not, using same equations of Bazant, part C will suffer serious local failures and be arrested up top on part A.
I, based on long experience of investigating structural damages, evidently take for granted that neither part C nor part A is rigid and analyse the matter in established way. Result is that both parts C and A suffer local failures and that they are arrested when the process runs out of applied energy after less than 1 second. Thus part C with some local failures at bottom should remain on top of part A after having caused some local failures there.
It is all described in my papers on the Internet and, according to prof. Ross Corotis, editor of ASCE Journal of Engineering Mechanics, also in a paper of mine to appear in his journal, JEM. This Ross told me in June.
It appears that prof. Ross Corotis value my opinion. I actually prove Bazant wrong!
PS - Visit my web site http://heiwaco.tripod.com and enjoy the view from my PC! Weather is good here. A little too hot for tennis but the beach is close.
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newton3376
The Truth Movement.....still not at 1%
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newton3376
The Truth Movement.....still not at 1%
- Joined
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Exactly.
bill smith
Philosopher
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Just yankin' your chain a little Newton. No hard feelings.
TruthersLie
This space for rent.
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Hey Bill.
So those steel plates should be fine right? And the concrete should also be fine.
Can water cut steel? Can flesh break bricks? Can a piece of paint ruin a satelight? Can a rock destroy 100 miles of forest?
why do you hide from SIMPLE things bill?
It isn't like I'm even asking you to provide your debunking of ryan mackeys physics of 9/11 volumes 1,2 or 3.
A W Smith
Philosopher
one more Newton
Yet another Newton can be seen at 2:00 in this video
Man I am old! I remember watching these as a kid.
Yet another Newton can be seen at 2:00 in this video
Man I am old! I remember watching these as a kid.
Test image
Heiwa,
Physicists deal with "rigid bodies" all the time.
Structural & mechanical engineers deal with "rigid bodies" all the time.
All of these folks use math whenever they deal with rigid bodies.
Ergo, their math DOES deal with rigid bodies.
.
I am starting to understand why you say so little, other than "read my paper".
Whenever you DO say something, it always ends up being so, uh, "interesting".
The "total forces/moments at fixed supports must be zero"??
Well, in a trivial, irrelevant & useless way, this statement is correct. In all buildings & in all structures that are not accelerating off in some direction (or rotation), the total forces & moments at EVERY SINGLE POINT in the structure must be zero. Nothing special about a "fixed support" in this sense. And it is (almost) irrelevant to the discussion of what is, and is not, considered to be a "rigid body". ("Almost irrelevant" because in structural testing & modeling, anchor points are usually considered to be rigid compared to the structure under test.)
It is a fundamental axiom of mechanics that the internal forces & moments generated by the structure exactly counterbalance the external forces & moments applied. Bringing the total forces & moments to zero.
Of course, if that were all that folks needed to know, we'd all be out of a job.
"Put it up & let's see if the total forces & moments balance to zero."
CRASH!!
"Ooops".
Engineers are interested in finding our whether or not the structure of the building can generate sufficient forces & moments to counterbalance the externally applied ones. And this means that the forces and moments at the fixed supports of devices under test are generally NOT zero.
In the top image in the image below, the point where the upper cantilever beam enters the wall is called a "fixed support". It resists all horizontal movement, vertical movement and rotations. This forces the slope of the beam to be zero (i.e., perfectly horizontal) as it enters the wall, regardless of the loads.
Cantilever beams
The bottom beam connects on the left side at a "simple support" (sometimes called a pin support). This one resists all horizontal & vertical motions, but does NOT resist moments (turning). This means that the slope of this beam can freely rotate to any position that the external loads impress on it.
The important point is that, in any loaded structure, the forces & moments within the test structure at the fixed supports are never zero. The forces & moments within the anchoring structure are never zero if a loaded test structure is bolted to it either. In both cases, the forces & moments at the anchor points (Heiwa's "fixed supports") always balance the externally applied loads.
But Heiwa is technically correct. "the total forces/moments at the fixed support must be zero". As they must be at EVERY point in EVERY stationary (actually non-accelerating) structure.
You can see, in this example, exactly how useful and enlightening his engineering pronouncements are.
BTW,
If the upper cantilever shown in the diagram above fails at any point OTHER than the fixed support, then you've done your analysis wrong.
.
Hard to type when you're laughing.
Tom
Heiwa,
.
Physicists deal with "rigid bodies" all the time.
Structural & mechanical engineers deal with "rigid bodies" all the time.
All of these folks use math whenever they deal with rigid bodies.
Ergo, their math DOES deal with rigid bodies.
.
.
I am starting to understand why you say so little, other than "read my paper".
Whenever you DO say something, it always ends up being so, uh, "interesting".
The "total forces/moments at fixed supports must be zero"??
Well, in a trivial, irrelevant & useless way, this statement is correct. In all buildings & in all structures that are not accelerating off in some direction (or rotation), the total forces & moments at EVERY SINGLE POINT in the structure must be zero. Nothing special about a "fixed support" in this sense. And it is (almost) irrelevant to the discussion of what is, and is not, considered to be a "rigid body". ("Almost irrelevant" because in structural testing & modeling, anchor points are usually considered to be rigid compared to the structure under test.)
It is a fundamental axiom of mechanics that the internal forces & moments generated by the structure exactly counterbalance the external forces & moments applied. Bringing the total forces & moments to zero.
Of course, if that were all that folks needed to know, we'd all be out of a job.
"Put it up & let's see if the total forces & moments balance to zero."
CRASH!!
"Ooops".
Engineers are interested in finding our whether or not the structure of the building can generate sufficient forces & moments to counterbalance the externally applied ones. And this means that the forces and moments at the fixed supports of devices under test are generally NOT zero.
In the top image in the image below, the point where the upper cantilever beam enters the wall is called a "fixed support". It resists all horizontal movement, vertical movement and rotations. This forces the slope of the beam to be zero (i.e., perfectly horizontal) as it enters the wall, regardless of the loads.
Cantilever beams
The bottom beam connects on the left side at a "simple support" (sometimes called a pin support). This one resists all horizontal & vertical motions, but does NOT resist moments (turning). This means that the slope of this beam can freely rotate to any position that the external loads impress on it.
The important point is that, in any loaded structure, the forces & moments within the test structure at the fixed supports are never zero. The forces & moments within the anchoring structure are never zero if a loaded test structure is bolted to it either. In both cases, the forces & moments at the anchor points (Heiwa's "fixed supports") always balance the externally applied loads.
But Heiwa is technically correct. "the total forces/moments at the fixed support must be zero". As they must be at EVERY point in EVERY stationary (actually non-accelerating) structure.
You can see, in this example, exactly how useful and enlightening his engineering pronouncements are.
BTW,
.
If the upper cantilever shown in the diagram above fails at any point OTHER than the fixed support, then you've done your analysis wrong.
.
.
Hard to type when you're laughing.
Tom
Heiwa
I have read the papers on your site. I have NEVER seen any engineering analysis. I've seen lots of pretty, irrelevant pictures, tho.
Please provide a link to a REAL analysis.
I sincerely hope that you've provided a competent, rigorous error analysis in the appendix to your study.
Tom
.
I have read the papers on your site. I have NEVER seen any engineering analysis. I've seen lots of pretty, irrelevant pictures, tho.
Please provide a link to a REAL analysis.
I sincerely hope that you've provided a competent, rigorous error analysis in the appendix to your study.
Tom
MIKILLINI
Incromulent Logic
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- May 3, 2007
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- 2,979
It surprises Me Bill hasn't discovered Frank's Ammonium Perchlorate theory. Or he may have, but prefers riding on Heiwa's shoulder instead.
Hey Tim,
Sorry, took a bit to spring free the time.
Your instincts are right on the money. There is an asymmetry to the damage that needs to be explained.
If the collision between the upper & lower parts had been horizonal, then the damage would have been symmetric into both pieces.
So what is the source of the asymmetry? Exactly what your instincts tell you: Gravity.
In a sense, it's the difference between jumping on somebody & having somebody jump on you. But with an extra twist...
The best way to view this is as the side of an incredibly steep slope subject to a rockslide. All the various rocks have had braces carefully designed & placed under them. Unfortunately, all those little braces are "mutually supporting". They cannot withstand their own load if too many of the adjacent braces are gone. And now, when the avalanche starts, even tho every individual collision does obey Newton's 3rd law (action = reaction), the whole landslide moves inexorably downhill once it gets going.
The twist is that you're going to ride down the avalanche in a shed above the debris. You'll see what I mean at the end of this post.
Again, the asymmetry is provided by gravity.
So, I think the question question of "why it progressed to the street" is simple. Just like an avalanche, it gathers momentum & mass as it moves down.
The separate (& independent) question is "why did it not move up into Part A?"
Unless you're pretty good with math, it's tough to get a sense of this from Bazant's paper (IMO). His is not a model of what really happened. It is idealized to favor an arrested collapse. And his idealizations are tough to translate into "what does this say about the real building as it came down?"
To get a gut feel, imagine that you are inside the upper block of the building, at about the 102nd floor, and everything below you, down to the crush floor, is transparent.
Before the collapse began, several of the floors on the 97th thru 99th floors had collapsed. This was seen from outside the building. Others were sagging and were pulling in on the external columns (& out on the core columns). Suddenly the connections failed, and the peripheral columns flung outward, becoming massively weaker (because of unsupported length & bowing).
As the collapse begins, the columns of the 98th floor buckle. They do NOT fail as Bazant describes them in any of his papers. Bazant examines them as if they buckled over a length of one floor, with 3 (or 4) knuckles. [See any of Bazant's papers that describe the columns becoming unstable.] This makes any of the individual straight segments between knuckle points equal to about 3' to 4' long. [Again, this is one of Bazant's "conservative", arrest favoring, idealizations.] Remember, short beam are strong, long ones are weak.
An examination of any of the collapse videos shows that the external columns did not fail like this. They failed at the column to column joints. That means that the lengths of the buckling segments was not 3' to 4', but rather about 36' long. This means that the real failures of virtually complete floor destruction extended up about 3 stories and down 3 stories from the 98th floor. Plus partial destruction up 2 additional & down 2 additional stories.
Lacking lateral support, the core columns buckled too, probably mirroring the outer columns (i.e., 6 floors total collapse, plus 2 up & 2 down partial.)
And when you pull the supports out from under a concrete floor that weight about 2.5 million Kg each, what happens? They all start to fall, together.
But there are still partial connections to the standing lower columns, so they don't free fall. The upper block does. The upper stories (3 stories of rubble first) then overtake the 3 stories of dragging rubble. The point is that the collision velocity between something that is free falling (upper block) and something that is ALMOST free falling (rubble) is much less than between something that is almost free falling (rubble) and something that is stationary (lower floors).
The impacts between the upper block and the rubble is a much less forceful impact than between the rubble and the lower stories precisely because of the lower relative velocities.
Meanwhile, a second effect occurs. The rubble is "packing into the lower 2 - 3 stories of the upper block. It's packing in at a low relative velocity, and it is being tamped in by air pressure and many, many collisions.
Now, we're ready for your observations from the 102nd floor. The debris has been packing in in the stories below you. At fairly low relative velocities. By the time the upper block has fallen 6, 7, or 8 stories, there is a LOT of debris packed into those lower couple of stories of the upper block. This debris became a barrier between the impacts and the upper block. The impacts were happening on the BOTTOM side of the debris. The upper Part A was riding down on the UPPER side of the debris. The growing debris layer PROTECTED the upper block from the destruction.
I tried to describe this in another posting here: http://www.internationalskeptics.com/forums/showthread.php?postid=4743226#post4743226
I hope this helps.
Tom
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Um, so where did I enter the picture? You did ask if I noticed that my post # 1357 was similar to Newton's post # 1356.
Notice that even on trivial matters, you can't ever acknowledge an error. I see why you worship Heiwa.
MIKILLINI
Incromulent Logic
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Are you at the "Bar" again?Thanks for agreeing that total forces/moments at any point in any structure is zero so that the point is not flying away. Of interest is then what stresses and deformations these forces/moments produce in the elements/structure. Pls note that no element is ever rigid. They all displace and rotate due to forces and moments applied. If they were rigid they could not do that and any structural analysis is of no interest at all. So when Bazant assumes that a complete assembly of elements is rigid in his WTC 1 analysis, you know that the complete analysis is fake!
Wow.
You're asking me to correct your giant pile of heaping nonsense.
You're asking me to answer your question.
How ironic.
Tom
Audible Click
The gap in the plot
Then why ask the question at all?
MIKILLINI
Incromulent Logic
- Joined
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But used by you in a trivial, irrelevant & useless way.