tsig
a carbon based life-form
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Moderated Steel structures cannot globally collapse due to gravity alone
- Thread starter Heiwa
- Start date
Are you serious? Or joking?
Yes, when B contacts A action/reaction forces F/-F develop. B may bounce! Or something may be broken.
A meteorite B impacting a roof A will
a) crush the roof A (reason is F destroys the roof*, -F does not destroy the meteorite)
b) demolish the house below A (reason - see a))
What are you trying to prove. WTC1 was crushed by a meteorite?
* if roof is strong enough to withstand F, it will not be destroyed! Then the meteorite will bounce or get destroyed; it depends on -F! Is the meteorite strong enough to withstand -F, it may bounce.
No, pls read my article at http://heiwaco.tripod.com/nist3.htm to find the answer. Topic is steel structures + gravity, etc.
But yes, no collapse occurs ever of lower object. It may be crushed down from top down. But that is not a collapse. Collapse is something else.
And again, topic is what happens to the upper object. According NIST, Bazant, etc, it should remain intact. It is however impossible, if it attempts to crush down the lower object just assisted by gravity.
And that's why the NIST/Bazant theory is nonsense.
I think it is time to lock this thread, moderator.
Your paper is pure nonsense.
Impact, fire and gravity collapse. Too simple for you as you deny the aircraft impacted the WTC in the first place; another delusion.
Grizzly Bear
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At this point if you do not understand the concept behind setting boundary condition in order to make a simplified model then you're not going to regardless of the experience or background your peers have that are trying to point out your errors. It's been said enough how badly your position reflects on your professional status and any credibility it lends you.
tsig
a carbon based life-form
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So the top of the buildings should have bounced off the bottoms and then bounced on down the street?
Christopher7
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The tilt was about 7-8° when the collapsed began and continued to increase to 20-25°. [[FONT="] NCSTAR 1-6 6.2.2 pg 167][/FONT]
In other words, the leading edge [tilt side] was collapsing faster than the trailing edge [hinge side] as would be expected due to the greater weight. As the weight increases on the leading edge, so will the tilt velocity.
This slight amount a greater resistance would be more than offset by the increasing weight on the leading edge. Any weight outside the perimeter would act as a cantilever with the exterior wall as the fulcrum, thus multiplying the effect of the added weight and crushing the leading edge even faster.
funk de fino
Dreaming of unicorns
C7
Do you think the top should have tilted right off and fallen to one side?
Do you think the top should have tilted right off and fallen to one side?
Christopher7
Philosopher
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Yes.
Newton's first law says an object in motion will remain in motion unless acted on by an external unbalanced force.
The top section was in motion to the side and down.
Both motions continued as the collapse progressed.
The side motion would continue and the top section would fall off the side of the building unless some external balancing force were applied.
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Center of gravity?
Questions?
Aircraft impacted the WTC towers, un-fought fires compromised the structure and the WTC towers fell in a gravity collapse.
911Truth is unable to refute this simple statement with all the 0.001 percent of the world's engineers working for 7 years~! Chris, even the experts closed a thread when you post your tripe at CTBUH. CTBUH could tell by your delusional post you were not able to understand what they said. Try to take it up an order of magnitude and present some evidence instead of hearsay, lies, and fantasy.
Questions?
Aircraft impacted the WTC towers, un-fought fires compromised the structure and the WTC towers fell in a gravity collapse.
911Truth is unable to refute this simple statement with all the 0.001 percent of the world's engineers working for 7 years~! Chris, even the experts closed a thread when you post your tripe at CTBUH. CTBUH could tell by your delusional post you were not able to understand what they said. Try to take it up an order of magnitude and present some evidence instead of hearsay, lies, and fantasy.
... the chief Structural engineer of the WTC agrees with me.
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Furcifer
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I see. So then a "progressive collapse" is the construct of a foolish mind not knowing of the frictional retarding force which prevents such an event from transpiring. Foolish structural experts!
Yah, no. Progressive collapse was well defined in building code well before 9/11 for a reason. Your account of what would happen isn't "supported" by the experts because they actually know this. Not that you need to be an expert to know what "progressive" means.
That the potentially destructive energy of a falling object is a function of its mass and velocity.
Therefore your statement that "dropping a piece of something onto the rest of that something can never cause global collapse" is insupportable nonsense.
But I see you now want the thread closed. So that you never have to admit to your (many) fundamental errors?
The boundary conditions are very important doing structural analysis. There you can check the reaction loads on the model, etc, etc, and easily verify if the loadings on the structure are correct.
The boundary conditions of a free falling body are very easy. There are no fixed connections to anything = no reaction loads! The load/force acting on the body just accelerates it.
I am amazed that NIST does structural analysis of a WTC7 upper structure that free falls. How did they do that? http://heiwaco.tripod.com/nist7.htm
Pls, provide one realistic example of a steel structure where "dropping a piece of something (i.e. a steel structure of certain type) onto the rest of that something (the steel structure of same type) can cause global collapse (of the steel structure)".
WTC 1 and 2 top parts should just get stuck on structure below amongst a lot of local failures. They are too weak to bounce up or to crush down the structure below.
Dave Rogers
Bandaged ice that stampedes inexpensively through
This seems to be another example of your adjacent=identical fallacy. These are different sections.
Nor do they claim that the large steel sections were ejected by air pressure.
Chris, I've told you how and where to contact the authors and ask them yourself. Until you do so, I have no more time for your idiotic strawmen.
Dave
Dave Rogers
Bandaged ice that stampedes inexpensively through
Rubbish. The top section needed to move 208 feet laterally to fall off the side. If the lateral motion was not sufficiently great to allow this to happen within the collapse time, it could not have fallen off the side. The collapse time was of order 12-16 seconds, so the top section would have to have been travelling at more than 17 feet per second to fall off the side. Please post your calculations showing that the lateral component of velocity of the upper block was greater than 17 feet per second, or admit that you are making up arguments without justification.
Dave
Gravy
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Chris, I took the time to assemble a website that answers exactly these kinds of questions. Is there any reason that you haven't availed yourself of the wealth of information there?
On page 1 of the engineering section:
Why didn't the towers, or the upper portions of them, topple over?
Why didn't the upper part pivot about it's base? See Bazant & Zhou (2001) Appendix II
Eduardo Kausel (MIT): Why the Towers didn't fall like trees
Frank Greening: An analysis of the tipping of the upper section of WTC 2 (PDF)
A simple graphic explanation of why the top of the south tower didn't fall to the side.
Physicist Dave Rogers on tipping of tower tops.
Structural engineer "Newton's Bit" on "tipping"
Gravy:
That's simple:
1. He's not interested.
2. He's got his own agenda to push which doesn't allow room for facts.
3. He's living in a fantasy world.
4. He's an idiot.
That about sums it up.
Now, don't be a nasty man and shatter his dreamworld. He may not be able to cope without it.
Bananaman.
That's simple:
1. He's not interested.
2. He's got his own agenda to push which doesn't allow room for facts.
3. He's living in a fantasy world.
4. He's an idiot.
That about sums it up.
Now, don't be a nasty man and shatter his dreamworld. He may not be able to cope without it.
Bananaman.