Christopher7
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You are missing the critical point. The columns were NOT buckling. FFA started before columns could buckle enough to break so that is NOT what happened.
See above.
Richard Gage Blueprint for Truth Rebuttals on YouTube by Chris Mohr
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Carlos
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What do you exactly mean by "buckle enough to break"?
Justin39640
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You know. A column bent over 45° still offers plenty of resistance to millions of pounds pushing down on it.
chrismohr
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Chris7,
You have accused me and others of saying that we are avoiding the isue of "at freefall" by using terms like "around freefall." Read TFK/Tom's recent post to me again:
http://www.internationalskeptics.com/forums/showpost.php?p=8184231&postcount=3992
Frame-by-frame measurements of the collapse video have been done by others which are more accurate than NIST's 1/7 of the frames measurements. The graph TFK put out clearly shows that the collapse varied above and below freefall rates.
Do I understand you that you are saying also that Stage One of the NIST diagram of the rate of collapse was an optical illusion caused by Building 7's collapse southward? It would still have dropped 7' even if it were falling backward (into its own weakest section, by the way). Is this your way of denying Lefty's charge that you are saying that the collapse began at less than freefall rates, THEN the bombs went off and there was freefall? Really? How was that accomplished 2 seconds into a collapse that had already started? Are you actually saying that the bombs went off and immediately the building went into freefall? If so, what was happening before that when the collapse was clearly beginning at much less than freefall?
BTW I found an "Ask a structural engineer" website and submitted my question about the meaning of buckling columns in a collapsing building. In the meantime, Tri's eyewitness account of incredible numbers of broken not bowed columns and his visual evidence here should not be ignored C7: http://s63.photobucket.com/albums/h1.../WTC Attack/ That's hundreds of pictures, many taken by a guy who was there.
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eta: actually this is the kind of unanswerable point that causes C7 to break out his "that's a denialist tactic" or somesuch. There might be no time for popcorn.
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chrismohr
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OK gang,
I found a chat room for structural engineers and asked some questions. If anyone answers they will have no idea I'm talking about 9/11. Here's what I posted there. It's the same stuff as here, we'll see if these SE's agree with Tom and Glenn et al or whether they agree with Chris7 and MM. I think I asked the questions fairly:
I am a layperson trying to understand some aspects of column buckling and am hoping for a relatively nontechnical answer.
1) My limited understanding was that column buckling and column breakage were two different things. If a building is collapsing and the support columns are "buckling," can that term apply to columns that are breaking at the welded connections and/or bolts breaking, or does buckling specifically refer only to a column that is bending at something like a right angle until it loses most of its strength?
2) From the point of view of loss of strength, does a badly bent column have much more resistance than a column that has snapped apart at its welded connections? Does a completely bent column have less than 5% of its initial strength? Less than 2%?
3) I'm somewhat familiar with Euler's theorem and am aware that this is a purely mathematical construct. In the real world, if a column is suffering from major stresses during a building collapse, is it likely that it would "buckle" by bending in half, or would it be much more likely to snap apart at the welded connections or other weaker spots?
4) Is this a good working definition of "buckling"? The term buckle refers to the instant in time that the column assembly goes unstable. It doesn't pretend to define the other 99% of the process, of how each piece comes apart.
Most of the time, buckles are studied as "3 point hinges", one weak point at the top of the failure, one at the bottom and one someplace between those two. (The middle hinge point is frequently shown half-way between the other two, but this is far from a rule.)
When a multisegment column assembly buckles, the hinge points form at weak points in the assemblies, which are again at the connections.
Thank you in advance,
Chris Mohr
PS to MM: You should try this sometime. Be sure to word the questions as neutrally as possible, ask about general principles relevant to a 9/11 debate without them knowing, and see what you get.
I found a chat room for structural engineers and asked some questions. If anyone answers they will have no idea I'm talking about 9/11. Here's what I posted there. It's the same stuff as here, we'll see if these SE's agree with Tom and Glenn et al or whether they agree with Chris7 and MM. I think I asked the questions fairly:
I am a layperson trying to understand some aspects of column buckling and am hoping for a relatively nontechnical answer.
1) My limited understanding was that column buckling and column breakage were two different things. If a building is collapsing and the support columns are "buckling," can that term apply to columns that are breaking at the welded connections and/or bolts breaking, or does buckling specifically refer only to a column that is bending at something like a right angle until it loses most of its strength?
2) From the point of view of loss of strength, does a badly bent column have much more resistance than a column that has snapped apart at its welded connections? Does a completely bent column have less than 5% of its initial strength? Less than 2%?
3) I'm somewhat familiar with Euler's theorem and am aware that this is a purely mathematical construct. In the real world, if a column is suffering from major stresses during a building collapse, is it likely that it would "buckle" by bending in half, or would it be much more likely to snap apart at the welded connections or other weaker spots?
4) Is this a good working definition of "buckling"? The term buckle refers to the instant in time that the column assembly goes unstable. It doesn't pretend to define the other 99% of the process, of how each piece comes apart.
Most of the time, buckles are studied as "3 point hinges", one weak point at the top of the failure, one at the bottom and one someplace between those two. (The middle hinge point is frequently shown half-way between the other two, but this is far from a rule.)
When a multisegment column assembly buckles, the hinge points form at weak points in the assemblies, which are again at the connections.
Thank you in advance,
Chris Mohr
PS to MM: You should try this sometime. Be sure to word the questions as neutrally as possible, ask about general principles relevant to a 9/11 debate without them knowing, and see what you get.
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Not 85 column assemblies.
Individual column segments.
85 assemblies x 47 stories / 2 stories assemblies per column segment = 2000 individual column segments.
Now how many do you need for it to be "a significant number"?
;-)
The question is "will the assemblies buckle in the middle of the segments or will the assemblies snap at the connections between the individual segments?"
You want to look at as many failures as possible. Which means looking at the all individual segments that failed.
Looking at assemblies that bent in the middle without snapping at the ends is also valid. That is, if you can find any. If you do, please point them out to me.
Thanks.
Christopher7
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No it does not. You persist in ignoring the FACT that you cannot get a perfect measurement from a video so many points are used and the software finds the average.
Even if you were right, the average is still FFA and the buckling columns in the NIST model are bending and providing resistance well into the FFA period. The NIST model is NOT falling at FFA as Sunder explained at the Technical Briefing. "There WAS structural resistance that was provided in this particular case".
Your confusion is due to your inability to understand what I clearly said. I did not say WTC 7 was falling backward, I said the point NIST was measuring moved inward and the camera angle saw that as downward.
Even if it had, the buckling exterior columns are still providing resistance when the building has descended ~20 feet. The NIST model is NOT falling at FFA.
Now you are doing what the JREFers do, proposing a totally stupid scenario, asking me if that is what I believe when you know darn well I have never said anything of the kind, and then noting how stupid it is. Although posed as a question, it's an insult.
chrismohr's point remains valid. Inward and backward are the same here, relative to the camera. How could this point move inwards (southwards) within your CD theory? Such a move would require the initiation of CD* to cause this point on the building to move horizontally for the duration of Stage 1, or ~1.75secs.
This is it odds with your (frequently and very clearly stated) claim that the FFA stage can only be explained by simultaneous removal of all vertical support. An initial southerly movement contradicts this.
You have painted yourself into a corner.
*eta: the final phase of CD, obviously, in your terms. We all know that the core was toast before the onset of "global collapse" of the exterior.
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Chris Mohr,
Chris, give it up.
You aren't playing the same game that he is. You are trying to use reason & logic & to leverage expertise in the pertinent fields.
He is doing something ... uh ... different.
There are no words that you will be able to write that will make the slightest dent in Chris7's ignorance.
His ignorance is not due to lack of knowledge. Or misguided facts.
It is willful.
It is intentional.
It is impenetrable.
You're wasting your time.
Just a suggestion.
Tom
Chris, give it up.
You aren't playing the same game that he is. You are trying to use reason & logic & to leverage expertise in the pertinent fields.
He is doing something ... uh ... different.
There are no words that you will be able to write that will make the slightest dent in Chris7's ignorance.
His ignorance is not due to lack of knowledge. Or misguided facts.
It is willful.
It is intentional.
It is impenetrable.
You're wasting your time.
Just a suggestion.
Tom
NoahFence
Banned
Now some idiot truther will try to find that SE forum and make an ass out of him or herself.
Time to first lie, two sentences.
Mohr did not say the measurement was "perfect", only "more precise".
chrismohr
Master Poster
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Neutral Answers from Structural Engineer
Hi again gang,
Here are answers I got on the SE site right after my questions:
1) My limited understanding was that column buckling and column breakage were two different things...They are.
If a building is collapsing and the support columns are "buckling," can that term apply to columns that are breaking at the welded connections and/or bolts breaking...No!
or does buckling specifically refer only to a column that is bending at something like a right angle until it loses most of its strength?...buckling refers to a column which has reached a critical load (Euler's formula) and becomes unstable.
2) From the point of view of loss of strength, does a badly bent column have much more resistance than a column that has snapped apart at its welded connections? Does a completely bent column have less than 5% of its initial strength? Less than 2%?...A column which has buckled is not badly bent. If load is removed, it will regain its initial shape and strength. If load is not removed, it will collapse. During collapse, it will probably become badly bent.
3) I'm somewhat familiar with Euler's theorem and am aware that this is a purely mathematical construct...no, it is not. It is accurate for slender columns within the elastic range.
In the real world, if a column is suffering from major stresses during a building collapse, is it likely that it would "buckle" by bending in half, or would it be much more likely to snap apart at the welded connections or other weaker spots? Depends what is causing the building collapse. If a column is buckling, that would trigger a partial or complete building collapse.
4) Is this a good working definition of "buckling"? The term buckle refers to the instant in time that the column assembly goes unstable...that is a pretty good definition.
It doesn't pretend to define the other 99% of the process, of how each piece comes apart...99% of what process, the collapse process? No, it does not deal with anything beyond the buckling process
Most of the time, buckles are studied as "3 point hinges",one weak point at the top of the failure, one at the bottom and one someplace between those two...Not true. A column can buckle with no hinges present.
(The middle hinge point is frequently shown half-way between the other two, but this is far from a rule.)...very far from a rule.
When a multisegment column assembly buckles, the hinge points form at weak points in the assemblies, which are again at the connections...Not necessarily true.
Thank you in advance,
Chris Mohr You're welcome.
These responses need more clarification for me to understand it better. Any thoughts?
Hi again gang,
Here are answers I got on the SE site right after my questions:
1) My limited understanding was that column buckling and column breakage were two different things...They are.
If a building is collapsing and the support columns are "buckling," can that term apply to columns that are breaking at the welded connections and/or bolts breaking...No!
or does buckling specifically refer only to a column that is bending at something like a right angle until it loses most of its strength?...buckling refers to a column which has reached a critical load (Euler's formula) and becomes unstable.
2) From the point of view of loss of strength, does a badly bent column have much more resistance than a column that has snapped apart at its welded connections? Does a completely bent column have less than 5% of its initial strength? Less than 2%?...A column which has buckled is not badly bent. If load is removed, it will regain its initial shape and strength. If load is not removed, it will collapse. During collapse, it will probably become badly bent.
3) I'm somewhat familiar with Euler's theorem and am aware that this is a purely mathematical construct...no, it is not. It is accurate for slender columns within the elastic range.
In the real world, if a column is suffering from major stresses during a building collapse, is it likely that it would "buckle" by bending in half, or would it be much more likely to snap apart at the welded connections or other weaker spots? Depends what is causing the building collapse. If a column is buckling, that would trigger a partial or complete building collapse.
4) Is this a good working definition of "buckling"? The term buckle refers to the instant in time that the column assembly goes unstable...that is a pretty good definition.
It doesn't pretend to define the other 99% of the process, of how each piece comes apart...99% of what process, the collapse process? No, it does not deal with anything beyond the buckling process
Most of the time, buckles are studied as "3 point hinges",one weak point at the top of the failure, one at the bottom and one someplace between those two...Not true. A column can buckle with no hinges present.
(The middle hinge point is frequently shown half-way between the other two, but this is far from a rule.)...very far from a rule.
When a multisegment column assembly buckles, the hinge points form at weak points in the assemblies, which are again at the connections...Not necessarily true.
Thank you in advance,
Chris Mohr You're welcome.
These responses need more clarification for me to understand it better. Any thoughts?
chrismohr
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Tom,
I'm still thinking that 35-40 bended steel columns would be enough. The "buckling" that initiated the collapse and which is visible in the NIST diagram is their explanation of the initiation of collapse. After the building is coming down very fast, I imagine the dynamic is more like smashing than buckling anyway.
Any responses from you to the anonymous reply post to me Structural Engineering questions?
chrismohr
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Much of what you say here has already been answered: others have taken BETTER (not perfet) measurements of the collapse than NIST did, and those measurements show above-and-below freefall varying rates. The 1.89 seconds of less than freefall almost perfectly matches the buckling time in the NIST Report; falling backwards or inside is the same from a camera point of view... And as for my last question, sorry if it seemed insulting but from my point of view it sounds like you are either saying that the 1.89 seconds was not a real drop, or if it was, the bombs would have had to do their work almost two seconds into the collapse. Are you explaining this by denying that the slower Phase One of the collapse never really happened?
Looks like I'm not taking Tom's advice to ignore you.
NoahFence
Banned
Yes. You should find another hobby because these retards have no intention of taking you seriously. None of them. Not Gage and certainly none of our cute little resident know it alls. You're wasting your time.
Miragememories
Banned
What it looks like to me is that you are all too often repeating what you have been told to say regardless of how well you truly understand what it is you are talking about.
MM
DGM
Skeptic not Atheist
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