Merged Discussion of femr's video data analysis

[Major_Tom]

I literally applauded femr2's debunking:

In my opinion, this is indeed the most interesting, original, and consequential debunking to have come out of femr2's data analysis.

I'm not sure femr2's result is important enough to justify a paper, but that's for femr2 and the engineering community to decide.

WD Clinger, before femr posted his data on the demo, what source do you use to determine if the WTC7 acceleration profile is "normal and expected"?

You have none. You sit on your ass and act as if it is normal and expected even before femr measures it, but you have no example of it being measured.

Femr gives us new information, do you have other examples of his results in some other building?

Anyone following these posts can see you believe yourself to be much more capable than you really are. You grab onto your own misunderstandings and get quite........excited?

It is like TFK all over again.
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I do believe you were probably the best regular poster here a few months ago.

Interesting watching your demolition in this thread. I'm not the only one who noticed this.

 

[Major_Tom]

In the simplest terms...

If WTC7 was an unprecedented event and, before femrs measurements, there was no example of a g to over-g early acceleration profile of which we knew in a comparable building, where did the term "normal and expected" get drempt up?

Don't you need some past history to determine what is "normal and expected'?



My comment that was twisted like a pretzel was pointing out that use of the term "normal and expected" in this first case, especially with the over-g portion of the curve, was brainless.


I still think it was brainless because we had zero like history to which to compare. Wise researchers have pointed out long ago that very high early accelerations can be expected for a building of this height, so some of us were not too surprised by the high early acceleration. But I have never seen anyone imagine they had enough information to declare it "normal and expected" for the profile witnessed.

Until you and Myriad. Somehow, you know through osmosis what the rest of us have to learn by observations in the physical world.


Now we are forming a history to which to compare. One case.

Good. One case is a good start.

 

[NoahFence]

So then you agree that the premise "it looked like a controlled demo" is false.

 

[Major_Tom]

This is a link to an excellent small thread in which simple crush down calculators are derived in July, 2008:

http://the911forum.freeforums.org/r...nd-collapse-energy-in-a-simple-model-t17.html

You see, these people will not be surprised about high early accelerations for WTC7 in 2011.

Early acceleration approaching g shows up in early crush down for high buildings.


But I don't think any of them would be so brainless as to declare a g or and above-g transient as "normal and expected" with no previous examples, especially the above-g portion.

Can you see the difference between calculating, forming a history, measuring..........as opposed to declaring through osmosis or vanity?


Or just talking out ones back side?
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WDC, please find the mistakes in the work by Dr G that you claim are there.

After that maybe we can talk about how you twisted my quotes in more detail.

 

[Oystein]

In the simplest terms...

If WTC7 was an unprecedented event and, before femrs measurements, there was no example of a g to over-g early acceleration profile of which we knew in a comparable building, where did the term "normal and expected" get drempt up?

Don't you need some past history to determine what is "normal and expected'?
...

Before weighing in on the case at hand first some semantics:
- "Normal" usually implies a body of experience, so I agree with you that determining what's "normal" usually needs some past history.
- "Expected" however only needs reasons; these can come from theory or extrapolation. Past history is not necessary.
- "Normal AND expected" requires past history if you construe the "and" the way it's used in Boolean algebra. A more loose usage might not require past experience.


Now on to the case:
For an accidental collapse, it would indeed not be too surprising if some part of the building fell freely for some time: This happens for any part that gets disconnected from its structural support before it hits the ground. As happened in the WTC7 collapse. If that's "expected" depends on the results of analysis performed. I guess it would catch most people (that have not done a full engineering analysis) by surprise that such a large section of the facade got into freefall / got disconnected from support structure without itself looking like it was disintegrating. But that is mostly a matter of personal incredulity.

 

[femr2]

This happens for any part that gets disconnected from its structural support before it hits the ground. As happened in the WTC7 collapse.

What part of WTC7 are you referring to, and how do you know such *happened* ?

 

[Major_Tom]

Then as you say...

"Expected" however only needs reasons; these can come from theory or extrapolation.

from experience or from theory. There was no "expected" concerning an over-g hump in the early WTC7 acceleration profile when Myriad and WDC claimed it.

That was my point at the time, and then he twisted the statements to something that suited his vanity without understanding what he was saying.

WDC is set on scoring points above all else. Reality is a distant second to scoring points.

It was just talk. Now we learn more with a new example.

 

[pgimeno]

I think it's quite natural to describe the columns in each individual perimeter panel assembly as columns in their own right.

OK, your opinion is noted.

But here's a remainder of what you said:

Firstly, it contradicts the NIST hypothesis of the mechanism in action...floor assemblies did not pull in the perimeter to the point where the perimeter buckled.

I suppose that if NIST had that wrong, you can cite the exact passage in which they use the interpretation of the perimeter as individual assemblies where they say that it's those which buckled. Can you please cite it for me?

If not, can you please take back that statement?

 

[pgimeno]

It is pretty obvious WTC1 failed differently than WTC2 if the upper wall kicks out over the lower wall.


All this is ignored by both yourselves and the NIST while you use a "copy and paste" long span truss mechanism for both towers and think this is "good enough".

Oh, where's that irony meter when one needs it...

Are you saying that the perps chose a different demolition mechanism for each tower, but in such a way that the overall looked similar enough as for a group of engineers to think it was basically the same?

Now that's worth going into this thread.

No need to guess about things that are observable. Best to look and map instead.

Now that you mention it, speaking of maps... Why not to look and map the parts of the NIST conclusions that would be affected by your findings, should they be true?

 

[pgimeno]

Even 1993 bombing resulted in no measurable seismic vibration. Hence, even a *boom* as loud as NIST expected probably wouldn't cause any seismic data.

Are you suggesting that there were explosives used to demolish the WTC towers, and that none of those, just as the 1993 van, was attached to vertical elements?

 

[ozeco41]

Are you suggesting that there were explosives used to demolish the WTC towers, and that none of those, just as the 1993 van, was attached to vertical elements?

You weren't supposed to notice the false implied analogy.

 

[Major_Tom]

Oh, where's that irony meter when one needs it...

Are you saying that the perps chose a different demolition mechanism for each tower, but in such a way that the overall looked similar enough as for a group of engineers to think it was basically the same?

I am saying if you stop dreaming and speculating and judging....and just open your eyes and look, the walls fell just as I describe.
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Also, if you studied enough to understand what the NIST WTC1 collapse initiation scenario is, you would see for yourself that it contradicts observables.


Your only advantage is you will not take the time to learn any of these things, and you will imagine your views are correct without checking them against observables.

I couldn't say it any clearer, yet you will not understand.

Now that you mention it, speaking of maps... Why not to look and map the parts of the NIST conclusions that would be affected by your findings, should they be true?

Already done and explained many times. I am confident you will not understand that either. It is like a memory that can always be reset to blank. Every time you post it is as if nothing was retained.

I swear, we were having the same exchanges 9 months ago. Zero acquired in all that time.

 

[Newtons Bit]

No, I'm simply attempting to get folk to realise that the columns didn't bend/deform, but instead failed along the bolt seams between perimeter panels.

Look up elastic buckling. Though you may have some difficulty getting a good definition on the internet. It's a form of buckling where the compression element does not actually yield or plastically deform. In other words, the peak stresses at the edges of the shape are below the yield stress. The members bends and elastically deforms. Kinks do not need to be created. The perimeter columns that failed at their splices underwent elastic buckling.

I think it's quite natural to describe the columns in each individual perimeter panel assembly as columns in their own right.

Regardless of what other people are saying here, you are correct.

Again, the point is to highlight that failure occurred along the bolt seams, not by buckling/bending/deformation of the box column sections themselves.

The buckling/bending is what resulted in the column splices failing. They did not fail in shear, as a direct result of the pull-in force, but rather in tension as the moment in the columns grew excessively large (as a result of p-delta).

I've outlined the math and the theory in the various threads I've started in this sub-forum. You may be able to read those and get an idea of whats going on, but this concept is going to require more knowledge than what can be gleaned from wikipedia or people rambling on the internet. You need about a semesters worth of Advanced Strength of Materials type classes.

 

[Major_Tom]

They failed just before and while 7 symmetrical ejections emerge lining up perfectly with the lowest points along the staggered break.

Here is one of the points:

7 symmetrical 78th floor ejections. That is from the lowest point in the staggered pattern, so it is the last one to break. And break it does with a vengeance. The geometry is pretty obvious if you look for it.

That shock movement is the cause of the light grey ejection. That happens across the whole east wall with a pretty amazing symmetry, always at the lowest points.

 

[Oystein]

What part of WTC7 are you referring to, and how do you know such *happened* ?

The upper part of the north face. I know this because it exhibited downward acceleration near g for a short while.

 

[Oystein]

Then as you say...

"Expected" however only needs reasons; these can come from theory or extrapolation.

from experience or from theory. There was no "expected" concerning an over-g hump in the early WTC7 acceleration profile when Myriad and WDC claimed it.

That was my point at the time, and then he twisted the statements to something that suited his vanity without understanding what he was saying.

WDC is set on scoring points above all else. Reality is a distant second to scoring points.

It was just talk. Now we learn more with a new example.

How about this:
Each time WDC does indeed score a point (finds a mistake in your arguments), you thank him for it and improve your argument. Each time he doesn't score a point, explain why you think he didn't score and move on. Don't keep whining.

 

[femr2]

Look up elastic buckling. Though you may have some difficulty getting a good definition on the internet. It's a form of buckling where the compression element does not actually yield or plastically deform.

Again the purpose was to highlight the actual nature of the break. I accept the behaviour could be stated as a form of buckling, but certainly not the more intuitive form as suggested by others, such as the three point hinge form suggested earlier in the thread.

I found one reference to the behaviour in the NIST report, but other than that all references simply cite *East Wall Buckled*...

Column splices failed at every third panel and columns sprung back from inward bowing

Whilst that doesn't quite capture the actual behaviour (every panel was involved, but with staggered break points) it at least affirms the spring-back behaviour of the panel columns.

As long as everyone is aware that the break ocurred at the bolted seams along the staggered path highlighted, it's all good.

 

[femr2]

The upper part of the north face. I know this because it exhibited downward acceleration near g for a short while.

So you are guessing.

Firstly, traced locations on the upper section of WTC7 exceed g at points (including the NIST trace), indicating they are probably still attached to other elements, such as the descending core...which is a bit of a problem for your assertion "This happens for any part that gets disconnected from its structural support before it hits the ground."

You are assuming that the structural support below the North face was disconnected. It may be that it was still connected, but posing little resistance by way of numerous mechanisms.

You are also seemingly suggesting detachment from the East and West walls, which is not the case. The East face may have become separated very late in descent, but the West face is certainly attached during the near-to-over-g period...

You know this ? May I suggest you reassess what you *know* ?

 

[femr2]

How about this:
Each time WDC does indeed score a point (finds a mistake in your arguments), you thank him for it and improve your argument. Each time he doesn't score a point, explain why you think he didn't score and move on. Don't keep whining.

W.D.Clinger ceased to make any real attempt to engage in productive dialogue quite a while ago, in preference to repeated and on-going general bickering and attempts at immature *point scoring*, even going to the extent of creating external web pages containing what he thinks are valid personal attacks against MT (though due to location they cannot be locally challenged of course)...which he folds in to many of his posts.

I suggest you also address W.D.Clinger, and request the same. He's failed to "thank and improve his argument" on many occasions.

The disagreement arose out of WDC's incorrect application of modus tollens in the first place...

I agree that folk should move on, once they acknowledge different/new information, but that MUST cut both ways.

If you are prepared to criticise MT, you must also be prepared to criticise WDC in the same public manner.

 

[Oystein]

Jeebus, I got femr2'ed!

So you are guessing.

Firstly, traced locations on the upper section of WTC7 exceed g at points (including the NIST trace), indicating they are probably still attached to other elements, such as the descending core...

Well yes, but the core (and the floor trusses) never held the perimeter walls up.

which is a bit of a problem for your assertion "This happens for any part that gets disconnected from its structural support before it hits the ground."

No. You are assumimg that my shorthand description of what causes things to fall at g is meant to be precise and exhaustive for all possible scenirios. Of course it isn't, silly.

You are assuming that the structural support below the North face was disconnected. It may be that it was still connected, but posing little resistance by way of numerous mechanisms.

There is no significant difference. Freefall means that there is nothing below the thing that slows down that fall. Or if there is, that there is aforce pushing downwards that adds to gravity. Oh, yes, I realize that there was. But the main force was gravity, and all the structure that previously hele the wall suspended above ground was decoupled and had ceased to do so any longer.

You are also seemingly suggesting detachment from the East and West walls, which is not the case. The East face may have become separated very late in descent, but the West face is certainly attached during the near-to-over-g period...
[qimg]http://femr2.ucoz.com/yukyku.gif[/qimg]

Seemingly. But not really. Again, you merely bemoan that my shorthand is not exhaustive and endowed with infinite precision.

You know this ? May I suggest you reassess what you *know* ?

No need to. I just don't have your fetish for 15 significant digits.