Moderated Continuation - Why a one-way Crush down is not possible

bill smith said:
What do you think ? Was it like 'a dead man standing' or something like that ? Nah....gravity is instant- take away he support and an object wll fall all in one movement. On the other hand a standing frame of steel will stand or it will slowly deform at the bottom and fall longways. Definately not straight down. Explosives explosives explosives may be the answer that explains this. (or maybe thermite). But not gravity...
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So, some time after the collapse further explosives went off which removed the supports from the columns which were still standing? Then they fell down?
 
Justin39640 said:
yeah im a loudmouth and sometimes i just stare at my screen mouth agape
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I'm more of a sarcastic smart ass...I have sort of a dark and cynical sense of humor too...so I'm rarely at a loss for words...

But I'll be damned if those truthers don't sometimes leave me doing the same thing....staring at the screen with a smile but also a WTF??!! look on my face...
 
bill smith said:
What do you think ? Was it like 'a dead man standing' or something like that ? Nah....gravity is instant-...
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Gravity is instant- Please explain saggy breats for me please???

bill smith said:
take away the support and an object wll fall all in one movement. ...
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Really??? Like the lateral support thata was removed from the columns that day?? Maybe, I dunno, the top of that spire was damaged, that is why you might see the reaction it had.




bill smith said:
On the other hand a standing frame of steel will stand or it will slowly deform at the bottom and fall longways. Definately not straight down. Explosives explosives explosives may be the answer that explains this. (or maybe thermite). But not gravity...
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This is approaching epic fail here.

What, if, I dunno, one piece failed and fell, why put added stress....Oh, who am I kidding. You will never understand because your ideas on, well, anything, is warped by hanging out with Heiwa too long!!
 
WTCdesign.jpg

Above photo shows the WTC design under construction; the core is quite strong, plenty of columns are interconnected and it is self-supporting and is used to support 4 cranes to assemble the bits and pieces of the towers; 80 assemblies of 3 columns/3 spandrels, each 11.1 m high, make up the four external walls that are bolted together; pre-fab floor sections with trusses are then bolted between core and walls every 3.7 m, and so on. The supporting elements - perimeter wall columns and core columns get weaker and weaker the higher you get. This composite structure has plenty of redundancy. Serious local failures due, e.g. a fire on some floors, between an upper part C and a lower part A cannot produce, e.g. a one-way crush down of A by C. Part C can never drop free fall! There are too many columns in the way and too many bolted connections everywhere.
 
Heiwa said:
http://heiwaco.tripod.com/WTCdesign.jpg
Above photo shows the WTC design under construction; the core is quite strong, plenty of columns are interconnected and it is self-supporting and is used to support 4 cranes to assemble the bits and pieces of the towers;
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You'll note, however, that the construction of the core has only proceeded to a couple or so storeys higher than that of the perimeter and floors, so this photograph is in no sense evidence that the core structure would be self-supporting if its unsupported part extended significantly higher than that.

Dave
 
Heiwa said:
[qimg]http://heiwaco.tripod.com/WTCdesign.jpg[/qimg]
Above photo shows the WTC design under construction; the core is quite strong, plenty of columns are interconnected and it is self-supporting and is used to support 4 cranes to assemble the bits and pieces of the towers;
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So the external tube, connected to the central columns by the floors, plays no role in supporting the 4 cranes?

How do you know?

80 assemblies of 3 columns/3 spandrels, each 11.1 m high, make up the four external walls that are bolted together; pre-fab floor sections with trusses are then bolted between core and walls every 3.7 m, and so on. The supporting elements - perimeter wall columns and core columns get weaker and weaker the higher you get.
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It's mainly the central columns that get weaker the higher you get. If the perimeter columns did the same, it would be obvious from the outside.

This composite structure has plenty of redundancy. Serious local failures due, e.g. a fire on some floors,
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Why is it truthers can never remember that there was BOTH a fire AND a plane crash?

A freakin' PLANE CRASH!!! What could possess you to "forget" that little tidbit of information?

between an upper part C and a lower part A cannot produce, e.g. a one-way crush down of A by C. Part C can never drop free fall!
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Where has anyone claimed that it did?
 
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Dave Rogers said:
You'll note, however, that the construction of the core has only proceeded to a couple or so storeys higher than that of the perimeter and floors, so this photograph is in no sense evidence that the core structure would be self-supporting if its unsupported part extended significantly higher than that.

Dave
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Yep... and three guesses as to what would happen if you DROPPED four cranes on the central column.

I'm reminded again of a building expert (can't remember who) way back in the mid-seventies, when the new King Kong remake came out. The remake had Kong climbing the World Trade Center instead of the Empire State Building. The expert said something I will never forget:

"The old buildings are much sturdier. The Empire State Building could handle a giant ape climbing on it, but the World Trade Center would have collapsed."

I thought of that quote again on 9/11.
 
So, Heiwa, I have a question:

Do you believe building codes since 9/11 are too strict? If a building cannot collapse from local failures, then why spend so much time, effort, and money on preventative measures?
 
Tony Szamboti said:
It does not contradict Anders Bjorkman's criteria where he explains that 1/10th of the structure could not crush down 9/10th's of a structure. The point Anders is making is that the smaller upper portion would be destroyed before it got through much more of the lower structure than it's own size, and it would lose it's ability to pulverize at that point.
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Why would it lose that ability? It's the same mass that was falling just a moment before.


Z said:
Um, quick question for an ignorant non-engineer:

As part C destroys portions of part A (and, I assume, has portions of itself destroyed as well), we're not actually claiming that the matter is annihilated, are we? So the falling mass - though no longer in the form of a rigid structure - is actually growing versus what it started at as part C, yes?

I mean, say part C was 1000 units of mass, and part A was 10,000 units. As part C meets part A, 50 units of mass are destroyed from each as part of any rigid structure, but now there's part C at 950 units, part A as 9950 units, and 100 units of mass - even assuming portions have been ejected or some converted to energy, let's estimate and say 90 units of mass remain from the impact.

So now we have 1040 units of mass falling onto 9950 units of mass... or, in other words, the total falling mass includes whatever remains of part C plus the damaged debris from both C and A that isn't ejected or converted to energy.

Seems to me, then, that as mass increases and the lower portion destabilizes - for surely destroying portions of its mass is going to cause structural instability - the destruction should increase, relatively, as it falls.

But I'm utterly ignorant of such things - tell me, does the disassembled mass from C and A figure further into the destruction of A?
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This seems to me to be a good example of rational logic.

Tony Szamboti said:
And why would it continue to move?
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Um...Newton's 1st Law?
 
NobbyNobbs said:
Why would it lose that ability? It's the same mass that was falling just a moment before.
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Part C gets decelarated and damaged in contact with part A. Happens every time and is the reason Why a one-way Crush down is not possible!
 
Heiwa said:
Say energy applied by part C with mass m dropping height h with acceleration g on part A is X.

Say energy required to deform parts C and A elastically before any failure is Y.

If X<Y part C bounces! Agree? No damages!

Let's assume X>Y. Thus energy (X-Y) = Z is available to cause local failures.

I suggest you need 10 Z to completely destroy the structure of one floor of parts A and C.

In this case Z will thus just produce local failures that damage 1/10th of one floor of parts C and A together.


Your car example is really stupid. A structure C(ar) which is 10 times heavier and 100 times more solid than part A is dropped on A. Evidently part C crushes part A.

On the other hand, if little part A is dropped on big part C, A gets damaged.
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So, uh, the BIG part, floors 98-110--the collapsing floors, drops onto, uh, the LITTLE part, floor 97, and crushes it. This is what everyone in the world except you and your mindless parrot perceives with the greatest of ease.

Next, the now-BIGGER part, floors 97-110, drops onto floor 96 and crushes it, adding its mass.

It would appear to most conscious, sentient humans that the big part gets bigger as the collapse continues, and the small part, the next floor in line, is always exactly the same size--one floor.

The mad contortions you have put yourself through to deny what is as plain as the nose on your face are a wonder to behold. You are hopelessly wrong, and everyone sane knows you are hopelessly wrong, yet you continue to parade your staggering lack of comprehension in front of real engineers.
 
FineWine said:
So, uh, the BIG part, floors 98-110--the collapsing floors, drops onto, uh, the LITTLE part, floor 97, and crushes it. This is what everyone in the world except you and your mindless parrot perceives with the greatest of ease.
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Sorry, part C, floors 98-110, is supposed to contact part A, floors 1-97, fixed to ground. If that takes place, both parts C and A, should deform and absorb energy. The only elements in contact are part C, floor 98, and part A, floor 97, where local failures may take place. To assume that only C crushes a bit of A, floor 97, is incorrect. Part A also crushes a bit of C, floor 98, and that is the beginning of the end, i.e. part A arrests part C, or what is left of it. As already explained several times, the energy applied is very small and should be absorbed within one second and associated local failures.
Bazant suggests that the energy applied can deform 110 floors of structure and then locally damage 280+ columns in interface C/A or in top of A, floors 96-97, enabling a second free fall, so that again 109 floors of structure deform and then locally damage another 280+ columns lower down producing rubble (part B), etc, etc. All pure nonsense.

Nobody in Germany and France where I am active supports Bazant! Or do you have any info to the opposite?
 
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