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Simple Calculations of Strain Energy

Hellbound said:
Heiwa:

The collapse arrest, specifically, interests me. Can you shoe me another case where a high-rise building failed at about 80% to 90% of it's height, and then arrested the collapse? It's a serious question.
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My job is actually to inspect steel (off shore) structures (some quite big) in service (before they fail) and I find fractures and minor failures all the time (that we fix). All are luckily arrested. But I have also inspected (off shore) structures after big failures, where parts really have failed (total rupture) and displaced. Not so easy to fix. But also arrested. We just find big fractures and buckling. My colleagues in the aviation business can probably report similar experiences.
Plenty of high-rise steel structure buildings have been damaged by fires and there were plenty of local structural failures, but ... all arrested. Same off shore.
 
Heiwa said:
No mass has failed, primary structural parts have failed and contact secondary structural parts. The latter fails.
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I'm interested , Heiwa.

You seem to be saying that when the broken core columns of the upper section impacted on the floor areas of the lower section, the concrete should remain intact? Therefore producing "no rubble" ? Was the lightweight horizontal concrete strong enough to resist such a huge downwards force?

If the floors would break then there would be a lot of rubble, no?

Perhaps you don't understand the word "rubble"? In French this appears to be décombres, or débris .
 
BenBurch:

The core of the 2nd tower did not stand for "several minutes" after the walls and floors had fallen. I believe it was significantly less than one minute...
 
Hellbound said:
Heiwa:

Finally, you post this:


I don't think you understand load bearing structures. The columns are NOT independent entities. They do not stand alone, with only vertical forces as the forces to consider. In fact, your point about strain energy being distributed leads into this. Although I believe your model to be incorrect, it is true to an extint. Buildings are designed to be able to "shift" load to other columns and support members when one area fails. That is done through the horizontal and diagonal cross-bracing between columns. If that fails, then each primary column suddenly must support it's load independently. Take a simple example:
[qimg]http://www.internationalskeptics.com/forums/imagehosting/thum_6874867d168ae4fa.jpg[/qimg]

The horizontal and diagonal cross-braces hold the primary columns in place (so the load pushes agains tthe length of the column) and help the columsn redistribute weight to each other should one become heavily loaded or fail.

What would happen to the above structure if Weight, instead of falling on the tops of the primary supports, fell at the spot marked B? Or C? What if it fell onto all the cross members?
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I am pretty stupid to climb around steel structures to check their integrity but it has a certain pleasure. Evidently I don't understand anything. The risk of slipping, falling, hurting or killing yourself is high. I know it by experience but have carefully avoided the last option. Just luck? I doubt any Nist engineer or Bazant, Greening or Seffen has ever even inspected a steel structure.

In WTC1 we are told all primary structure - the columns - fail at initiation. Very well. After that the same columns - the loads shift - can only contact and damage secondary structure (the floors) that are pretty weak. But the secondary structure is only locally failed and will get entangled in one another. Collapse stops. No rubble.

Your example seems to be an open, airy structure. Any free weight, dropping on any non vertical member, will just slip or bounce off. No damage. Maybe an indent. I have seen that too (after it happened). Big weights (cranes) dropping down on my structures. Result. A big buckle on top, fractures and deformation of supporting structure below. Collapse arrested. All the time.
 
GlennB said:
I'm interested , Heiwa.

You seem to be saying that when the broken core columns of the upper section impacted on the floor areas of the lower section, the concrete should remain intact? Therefore producing "no rubble" ? Was the lightweight horizontal concrete strong enough to resist such a huge downwards force?

If the floors would break then there would be a lot of rubble, no?

Perhaps you don't understand the word "rubble"? In French this appears to be décombres, or débris .
Click to expand...

You have misunderstood. If a broken column (primary structure) contacts a floor after initiation, it will only punch through the steel/cement floor sandwich assembly (from above or below). As the cross area of the strong column is small and the floor is very big the amount of rubble (a little cement) is negligible. And that's all that will happen ... at say three, four, five floors ... at perimeter and core. But any floor will only fail at a wall or at the core and hinge around the other edge. No pan caking or free fall.
You are not alone misunderstanding. Nist & Co belongs to your team.
Thanks for the French lesson.
 
BenBurch said:
Collapse proceeded from the walls not the core!

Please study some before you make a fool of yourself again. OK?

-Ben
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The second collapse, pls use destruction, was WTC1. This is the one I study in my articles. What you say does not make any sense at all. Collapse proceeded from the walls? Are you OK?
 
Apollo20 said:
BenBurch:

The core of the 2nd tower did not stand for "several minutes" after the walls and floors had fallen. I believe it was significantly less than one minute...
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Ah, thanks! I was looking at timestamps on two pictures, and assuming they were correct.

Still the point is that clearly the core surviving would not change the ultimate result.
 
[X] said:
So now the theory involves, among everything else, corrupting specifici scientific terms.
How big is your theory going to get, before you admit it can't be amintained?






Essentially, yes.






My bolding.
You have just admitted that you do not understand why an input of energy greater then the amount of energy the building can physically sustain without failure leads to building failure.
Do you honeslty think that?
It's like saying you cannot comprehend why placing a 5 tonne load on a 3 tonne rated forklift will cause problems.
There's no point in making a discussion of this, because it is so blatantly rediculous.
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Heiwa's incompetent and blatantly ridiculous assertions have been pulverized into fine dust by, among others, Newton's Bit, RWGuinn, RMackey, Dave Rogers, beachnut, and Myriad.

The phrase, "ineducable as a twoofer" deserves to enter the language.
 
Heiwa said:
You have misunderstood. If a broken column (primary structure) contacts a floor after initiation, it will only punch through the steel/cement floor sandwich assembly (from above or below). As the cross area of the strong column is small and the floor is very big the amount of rubble (a little cement) is negligible. And that's all that will happen ... at say three, four, five floors ... at perimeter and core. But any floor will only fail at a wall or at the core and hinge around the other edge. No pan caking or free fall.
You are not alone misunderstanding. Nist & Co belongs to your team.
Thanks for the French lesson.
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How many times do you need to be corrected?
 
Heiwa said:
Stupid? The bolted connections between any floor/horizontal core beam should shear off when the beams were displaced, as the core columns supporting the beam were displaced, i.e. the floors are sliced off the beams. Weakest parts. No rubble produced. Except some sheared off bolts.

But let's assume the core beams do not slice apart the floors' connections to the beams! Collapse arrest will occur much earlier.

If anybody is stupid, it is Nist. It should analyse in detail the local failures after initiation. Be professional. Do a proper job. That's all I ask for. Not mess up the investigation witn nonsense.
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Speaking of nonsense, the real engineers and scientists here exposed you as a complete incompetent. When will you correct your embarrassing blunders?
 
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