Newton vs NIST by Jonathan Cole - Japanese

[wildbilln864]

[William Seger]

1. Pseudo-science at its worst

If a falling structure uniformly accelerates, then the apparent weight of the structure is less than it was at rest. (Italics in original.)

David Chandler measured the position of the tower roofline in a video at 5-frame intervals. He then drew a straight line through the points and declared that the straight line meant that the top section was "uniformly" accelerating. That is his first invalid inference, and one that shouldn't be expected from a scientist: It only meant that within the limits of his measuring technique, on average, the acceleration was fairly uniform. Measurements taken on a much finer scale could easily show waves of fluctuations instead of Chandler's straight line.

Chandler then uses that (invalid) "uniform acceleration" premise to infer that the structure must have been exerting a reaction force of only about a third of the weight of the top section. But, Chandler declares, that's only 1/9th of what the structure was designed to carry (i.e. three times the weight), so "something" must have removed 8/9ths of the columns, very rapidly, and that could only be magical silent explosives.

That conclusion is abject nonsense on its face, even if real-world KABOOM-type explosives were used: Removing 8/9ths of the columns would not produce a uniform acceleration! I defy Chandler or Gage's other "experts" to propose any realistic failure modes that would produce a uniform acceleration, but blowing out columns certainly would not.

What would happen is that the remaining columns would quickly buckle. When a column buckles, its carrying capacity drops drastically, down to virtual nothing if it folds in half, or exactly nothing if it breaks before it bends that far. For a 12-foot column, buckling would begin after only a few inches of downward deflection. After that point, the column would no longer be able to provide the three-times-design-load reaction force Chandler assumes (which isn't quite accurate, but it doesn't matter). And as the reaction force diminished, the falling mass above would see an increase in acceleration, up to and including one full g before impacting the next floor.

But even worse for Chandlers nonsensical conclusion is that column buckling was not the primary failure mode in the WTC towers. Instead, floor joists and beams were mostly ripped from their connections before columns buckled, leaving unbraced columns to buckle or be pushed aside later. The connections sheared after decelerating the falling mass for only a fraction of an inch, after which the debris would go into free-fall until it hit the next floor.

So, even if magical silent explosives had been used, the collapse would have been thousands of individual failure events, with thousands of different clumps of debris alternately decelerating when they hit a floor and then accelerating again when that part of the structure gave way. All you could hope to measure at the roof, with the top riding down on a cushion of debris and individual failure events spread out over time, would be an average of all those events, and an average acceleration of debris that was actually undergoing wide fluctuations in acceleration, up to and including free-fall.

And the point is, the same thing would happen with a purely gravity-driven collapse, with failures caused by the dynamic impact loads, which Chandler completely ignores with his "uniform acceleration" nonsense. No magical silent explosives required. Several people (e.g. Dr. Greening) have done the type of dynamic analyses that Chandler doesn't even attempt and come up with collapse rates that match well with the observed rates, so there's really no mystery that needs to be solved with magical silent explosives.

There is no reason to think that Chandler's point measurements actually imply uniform acceleration, and since there is no realistic way to get a uniform reaction force from failing structural components, there is no logical reason to expect uniform acceleration, even with 8/9ths of the columns blown away. And without uniform acceleration, the rest of the Chandler/Cole argument is worthless. It may pass for "science" in Trutherville, but the only thing that Chandler and Cole prove is that being able to state Newton's laws and being able to apply them intelligently in the real world are two different things.

[wildbilln864]

2. pseudo-science indeed..

But I guess that's all you have in the face of structural engineers, chemists, metalurgists, architects and other professionals when using JREF quacks as authorities, eh william!
By the way can you give us just one example of a "gravity driven collapse" where the entire structure was demolished and turned into rubble? Besides of course on 9/11/01.
I thought not!

[William Seger]

3. Yes, I can

I've mentioned it several times: Skyline Towers, Baileys Crossroads, VA, 1973. That was when I was working as a structural draftsman a few miles away in Alexandria. That collapse started when concrete forms were removed from a floor before it was cured enough to support its own weight, but why did it continue through 22 cured floors, all the way into the sub-basement? The engineers in that office didn't have trouble explaining it to me: The impact load of falling debris was far above the design "live load" for the floors, so the floor slabs simply sheared away from the columns ("punching shear&quot .

But is there some reason that you want to discuss that instead of the obvious flaws in Chandler's "uniform acceleration" nonsense? Or any of Gage's other "experts" nonsense, for that matter?

But no, my criticism of Chandler's argument did not come from any "JREF quack authorities," nor does it appeal to anything but facts and reason, which I think I stated pretty clearly. If you didn't understand what I said, feel free to ask questions.

Really, I can never tell if you run away from discussing any of it because you don't understand it, of because you do. So let me ask you a question (you owe me one): I explained how a gravity-driven collapse could progress at an average acceleration of 2/3g, because it's an average of everything from brief, high decelerations due to impacts to actual free fall when structural elements gave way. Now, can you please explain how a controlled demolition could possibly produce Chandler's claimed "uniform acceleration" of 2/3g?

(Actually, feel free to ask Chandler or Cole or any of Gage's other "experts" for help. I'll wait...)

[wildbilln864]

4. fail again Seger!

this building did not collapse all the way like the trade center towers! As seen in this picture! You are getting desperate! Try again!
you did notice where I said the entire structure turning to rubble right? guess you didn't. how convenient!

[William Seger]

5. Nope

Structurally, that is a separate and independent building. The building that collapsed did so completely, up to an "expansion joint" between it and that building. The purpose of expansion joints in large reinforced concrete structures is to allow the separate structures to expand and contract independently of each other, and thus not crack the concrete. It also saved that building from the progressive collapse, but it doesn't save your collapsed argument: It was a gravity-driven complete collapse of that independent structure, and you refuse to even think about the simple explanation that real experts have for it.

Not surprisingly, you also dodged the question I asked you about Chandler's "uniform acceleration" nonsense. How convenient.

[wildbilln864]

6. also structurally....

nothing like the WTC towers. Right William? Not built to withstand multiple impacts by a fully loaded passenger planes like the Twin Towers were. You failed but you will not admit it. That's why I don't think you're arguing from sincerity. How long's it been now? Over a decade and you've convinced no one yet you tow that line. Strange indeed.
Simply put. There never has been a total and complete gravity driven collapse unless deliberate demolition methods were used to cause it. You even admitted your example only collapsed because the supporting structure was removed first before the building was ready to support the weight. Do you see the problem with that William? No of course you don't. Or at least you won't admit it.

[William Seger]

7. It was "like the WTC towers" (and most other buildings) in the one thing that mattered

... i.e., its floors were designed to carry the expected "live load" plus a safety factor, not the impact load of a floor above falling on it, which was the point. You asked for an example of a gravity-driven collapse completely destroying a building and I gave you one, and instead of addressing the issue, you want to say, "Oh, but it didn't bring down the building across the expansion joint, so it doesn't count. Nyah, nyah, nyah." Yes, it certainly does count as an example of the principle of progressive collapse. "Never happened before" is not a technical argument; it's just an ordinary logical fallacy. Since no buildings like the WTC buildings ever experienced anything like the events of 9/11, the uniqueness of the result is meaningless. But following your "logic," since nothing like Skyline Towers had ever happened before (or Ronan Point Apartments, or L'Ambiance Plaza, of Tacoma Narrows Bridge, or a long list of other unique collapses), they all must have been brought down with magical silent explosives.

And after trying to derail any discussion of Chandler's faulty logic and pseudo-physics with that irrelevancy, yet accuse me of not "arguing from sincerity?" You are a hoot, wildbill.

> Over a decade and you've convinced no one yet you tow that line.

Welcome to the first day of the rest of your life. I confidently predict that there will never come a day when "truth movement" bullshit goes unchallenged, whether it's by me or someone else who believes that truth actually matters and that the "truth movement" is an intellectual blight on our society. I continue to trust that, if provided the information, rational people will go beyond that bullshit, look at the actual facts and technical arguments, THINK about what's being said on both sides, and come to the obvious conclusion. Since I don't count "truthers" in that group, I don't expect any of them to change their minds, so your lack-of-progress report is not surprising nor relevant to my personal motivations. Bullshit that's ignored doesn't disappear; it procreates in dark corners. I certainly can't take all the credit, but comparing this board today to what it was in, say, 2006, apparently quite a few people have been convinced that DU is not a dark corner.

That reminds me, did I mention that Chandler's "uniform acceleration" is bullshit? Again I'll ask, does your reluctance to discuss it mean that you don't understand it, or that you do?

[wildbilln864]

8. nonsense William!

"its floors were designed to carry the expected "live load" plus a safety factor,..."
floors do not support loads. Walls and columns do. Walls an columns do however support floors! Really, it's obvious you are unfamiliar with building construction! Yet you think you're more knowledgeable than actual physicists, engineers and architects who have decades of experience and training each! So fucking funny!

[William Seger]

9. Really?

If you know of a building with floors that don't support loads, I strongly recommend staying out of that building.



ETA: Wikipedia definition of floor live loads:
]

Roof and floor live loads are produced during maintenance by workers, equipment and materials, and during the life of the structure by movable objects, such as planters and people.

[wildbilln864]

10. loads yes, depending on what you define as load.

structure, no. Walls and columns are typically directly under upper walls and or columns.

[William Seger]

11. WTF does that mean?

In structural engineering, there's only one definition of "load." You didn't click my link?

Structural loads or actions are forces, deformations, or accelerations applied to a structure or its components.

As shown in the diagram, in the WTC towers, the floor design live loads ranged from 55 pounds per square foot to 82.5 psf, and they were already carrying furniture and partitions. How much impact force do you think would be generated if just one floor above fell 12 feet? That's all it took to trigger the Skyline Towers collapse.