Derek,
Sorry, just not much time for you today. Business trip looms...
So, brief reply.
That's a lot of bravado Tom, bravo! But you still fail to answer the simple questions. Please do so, if you're able. There are plenty of calculators on line that use the Structural Stability Research Council’s numerical methods, just plug in the geometry, materials and click the mouse button! Don't let your budding twoof-slaying fans down, they are cheering you on as I type.
I've given you my answer.
I'll leave the "brainlessly plug into on-line calculators" to you.
One thing that you might do first is to produce a sketch of the constraint & loading conditions
at the moment of buckling of any particular column that you (not me) might be interested in.
C'mon, kid. You can do this.
Come to think of it, you probably can not do this.
Either way, it's a virtual certainty that you won't do it, of course. That takes effort...
2a. How did no energy dissipate from the WTC 7 columns? Explain this in terms of the Lagrangian energy theory. Tell me all about the dissipation term; please don't forget that ol' serpent in the garden.
There is a starting point for all Hades breaking loose, and NIST makes this much clear. The unstable condition started at column 79, you and NIST both stated it buckled. You and NIST both stated the others buckled as well. If you want your cop out (bolt/weld) fantasy to work out, you must demonstrate that either Cantor or Frankel was in error with their AISC connection designs, something you might have a hard time doing, I suspect.
Hey kid, I've got a question for ya.
What would you call it the failure mode if a 9 story tall, thick wall welded rectangular box column or I beam were placed into a giant Instron, its ends constrained in holding fixtures and compressed axially until it formed 3 kinks, and was additionally load until the two ends met with the whole column ultimately shaped in a giant flattened "Z". (... as described by Bazant in his several papers)
Most engineers would call that failure mode "buckling".
Now, in contrast, what would you call the failure mode of a 9 story tall column, made up of three 3-story segments that were bolted and/or welded together, with many lateral constraints along its height, several of which had been damaged or removed, that had multiple massive side loads along its height because several of the lateral constraints that had failed weighed many tons, and ultimately it separated from its constraints, bowed into a giant arc and, as it collapsed, the bolts & welds holding the segments together snapped, and the whole thing fell to the ground.
Most engineers (including me) would call that failure mode "buckling", as well, since that's how the whole process started.
Funny that you recognize only the first situation.
Funnier that you think that you can TELL me what I meant, when you extract only the single word and don't ask for any further details.
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2nd question...
If the first column managed to stay nearly intact during its compression (i.e., not split its welds seams wide open & separate into several disjointed segments), how do you think that the plastic strain energy absorbed in its permanent deformation would compare to the plastic strain energy of, say, fracturing 4 7/8" diameter steel bolts between the 1st & 2nd column segment?
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3rd question...
If you were not around to witness the testing, how would you tell from the pieces after the fact which failure mode predominated?
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Now, with this last comment in mind, try to say something interesting & pertinent about the shape of all those columns in the photos of the WTC7 rubble pile that I directed you to earlier.
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And that's all the time that I have for your nonsense today. I'll be busy for about 3 days.
tom
