Moderated Steel structures cannot globally collapse due to gravity alone

[Heiwa]

Heiwa,

You've got a massive case of "circular illogic" working here.

You have attempted to use a definition to prove your conclusion.

BY DEFINITION, non-progressive failures do not progress from a single point to global failure.

BY DEFINITION, progressive failures do.

Are you truly saying that "progressive failures are unknown in large steel structures"?

Surely you are not that unknowledgeable about the world of large structures?

Surely someone has pointed out to you buildings such as the Sight & Sound Theater, McCormick Plaza, and the Windsor Towers. Surely you have heard about the massive building failures that happened as a result of the fire bombings of the cities of Dresden & Tokyo. Surely you have seen flaming oil derricks collapse.

All examples of progressive failure of large steel structures due to fire alone.

To be sure, these types of failures are extremely rare. It is a testament to the dedication of engineers who are acutely aware of single point failures in their designs, and eliminate as many as humanly possible.

How do engineers learn about failure modes? When things fail. It is the embarrassing, tragic nature of the business.

The failure of WTC7 pointed out a new failure mode that they hadn't known previously that was particular to designs like that building.

But it has been known for a long time that fire can and, in the absence of preventive measures, WILL take down steel buildings. Or do you think that they go thru billions of dollars per year in thermal insulation, sprinklers & other measures for the express purpose of protecting the steel from the fire for no reason?

Every once in awhile, as in the case of the Towers & WTC7, a failure progresses to total collapse. And whenever this does occur, your fundamental thesis is completely wrong. It DOES happen as a result of a single component failure. The LAST component before total collapse. Because all the other structural redundancies have already been compromised.

In the WTC7 collapse, there are thousands of components that failed without leading to total collapse. But the building did NOT reach an equilibrium. It was still IN THE PROCESS of total failure.

Loads were in the process of redistributing, metal was in the process of yielding, of creeping, of flowing, etc. Fires were in the process of heating new members.

And when that final collapse began, it DID begin as a direct result of a SINGLE component that failed - whatever it was, it might have been something as simple as a single bolt snapping.

The point is that, between the time the fires started and the building collapsed, the building never achieved a true static equilibrium.

And this simple picture applies to every progressive failure that has ever occurred.

tk

Thanks, tk, for long post. Where do I provide a DEFINITION to prove a conclusion? In all my articles about structural damage analysis I simply point out that you have to establish the path of all structural failures, step by step, to understand what happened. One structural failure causes a second structural failure and so on. Re WTC1 one failure produced by gravity cannot produce the million of failures we see on all videos. The first failures would be arrested at once, which I clearly describe. No crush-down is possible. And that applies to all steel structures! You cannot destroy a steel structure by dropping a piece of it from above on itself!

The little piece you drop will be destroyed prior to major failures of the structure below. Happens every time. Or the small piece will just bounce!

NIST thinks otherwise but ignores, e.g. friction between failed parts. So the NIST report becomes science fiction (no friction!). Include friction in the analysis and you will find why structural failures are arrested.

Bazant is worse. His model is 1-D, a line, that shortens itself. I have debunked it at http://heiwaco.tripod.com/nist3.htm . Pls read it and point out any errors in my conclusions. A&E911truth.org liked that article very much and made me their personality for February 2009. Great honour.

Re Dresden my mother-in-law witnessed the destruction from a distance (Naundorf 30 kms west of Dresden). Yes, the town was bombed February 1945. Very few steel structures there! Most of it was stone and bricks.

 

[Architect]

And yet, Heiwa, you seem strangely unable to post competent structural calculations. Hmmm.

 

[Smackety]

<snip> Steel structures cannot globally collapse due to gravity alone ... <snip>

Let's build a space elevator!

 

[GlennB]

You cannot destroy a steel structure by dropping a piece of it from above on itself!

What if 49% of the steel building is dropped onto the other 51%, from a height of:

1 floor?

10 floors?

100 floors?

Will the collapse immediately be arrested in each case?

 

[Heiwa]

What if 49% of the steel building is dropped onto the other 51%, from a height of:

1 floor?

10 floors?

100 floors?

Will the collapse immediately be arrested in each case?

How do you drop 49% of a steel structure on the other 51%? Do you lift it with a crane and then release it? Let's discuss WTC1 instead.

Bazant suggests that if you drop from 0.5 m the 53 m top part C (13 stories) of WTC1 on the 350 m lower structure (97 stories) - part A, then storey 97 (floors 96-97) will be crushed and replaced by a 0.9 m thick layer of compressed rubble - part B.

Strangely enough part C - the top part - remains intact! Only part A is damaged, i.e. floor 97-96, becomes rubble.

Reason for this is that Bazant and NIST assume that part C is indestructible ( a rigid box!).

That assumption is wrong. Evidently also part C will be damaged.

If you read my analysis you find that I suggest that no compressed rubble is produced by an 0.5 m drop.

Like in any collision between two structural bodies, the stronger sub-parts will damage the weaker ones of both bodies. In the WTC1 case the vertical columns of both parts A and C will evidently slice through the thin floors of parts A and C after an 0.5 m drop. No rubble is produced. Only local failures.

No impact.

And when the columns have sliced, say, 3 floors in part A and 3 floors in part B there will be 6 sliced floors hinging down around their end connections and ... 6 floors will rub against each other. Plenty of friction there. And the friction will arrest further destruction. Actually the destruction will stop earlier as part C can never free fall any distance.

Parts A and C will always be connected by columns that are just buckling. Only result will be slow downward displacement of part C.

As if a crane slowly lowers part C on part A and equilibrium will be re-established = arrest.

Same will happen in your examples: the stronger sub-parts of the 51% section will damage the weaker sub-parts of the 49% section (and vice versa) and soon the weaker sub-parts will get entangled into one another ... and destruction will be arrested. Friction takes care of that.

Hopefully you agree that your 49% section is not indestructible (rigid)?

If you only do that, you also agree that the NIST/Bazant model/theory/explanations are nonsense.

Thanks for asking an intelligent question.

 

[funk de fino]

"Fires were in the process of heating new members"

Those fires were not hot, nor longlasting in any location in that building.

Lying makes you look very immature.

 

[twinstead]

If you only do that, you also agree that the NIST/Bazant model/theory/explanations are nonsense.

Why on Earth would anybody agree that the NIST/Bazant models are nonsense? Why, anybody who was stupid enough to think that every expert on Earth who actually agrees with NIST and Bazant (you know, just about ALL of them) doesn't know what he is talking about, and some ship engineer posting on a relatively obscure internet forum REALLY knows what it is all about would be laughed at and ridiculed as a stark, raving idiot.

Oh. Wait. Never mind.

 

[beachnut]

...
And the friction will arrest further destruction
...

how much friction, by the numbers. Show your work. Oh, you have no real work, just kids on beds, pizza boxes, and sponges.

There is over 130 TONS of TNT energy due to gravity to arrest. How much friction you got on your posse.

Calculate the numbers in joules or appropriate units and present them. You can't do it.

 

[Heiwa]

Why on Earth would anybody agree that the NIST/Bazant models are nonsense? Why, anybody who was stupid enough to think that every expert on Earth who actually agrees with NIST and Bazant (you know, just about ALL of them) doesn't know what he is talking about, and some ship engineer posting on a relatively obscure internet forum REALLY knows what it is all about would be laughed at and ridiculed as a stark, raving idiot.

Oh. Wait. Never mind.

You got it?! NIST and Bazant assume upper part C does not get damaged at all during crush down (it happens at push up 15 seconds later - it must get damaged).

 

[Baylor]

You got it?! NIST and Bazant assume upper part C does not get damaged at all during crush down (it happens at push up 15 seconds later - it must get damaged).

Can you quote them both please?

 

[Heiwa]

how much friction, by the numbers. Show your work. Oh, you have no real work, just kids on beds, pizza boxes, and sponges.

There is over 130 TONS of TNT energy due to gravity to arrest. How much friction you got on your posse.

Calculate the numbers in joules or appropriate units and present them. You can't do it.

Let's do some calculations. The drop releases 0.27 GJ of kinetic energy. It corresponds to less than two gallons of fuel. Where did you get 130 tons of TNT from?

For a 60 m long perimeter steel wall to slice a thin floor requires 0.03 GJ and for the core to do the same thing 0.02 GJ is required. Thus to slice one floor 0.08 GJ is required (only two perimeter walls slice). So it looks as if only 4 floors will be sliced; two in the upper part C and two in lower part A. Then all energy is consumed as local failures. Even without friction the collapse is arrested. And no rubble was produced.

See, I did it.

 

[Heiwa]

Can you quote them both please?

Read my articles!

 

[Baylor]

Read my articles!

No thanks.

Can you quote them both please?

 

[Heiwa]

No thanks.

Can you quote them both please?

I do it in my articles. They are available free of charge on the Internet.

Bazant & Co. write in their latest article 2008, e.g.:

During the crush-down, the falling upper part of tower (C in Fig. 2 bottom), having a compacted layer of debris at its bottom (zone B), is crushing the lower part (zone A) with negligible damage to itself.

This is evidently wrong. C will be damaged at once and no layer B will be produced.

NIST as you know just suggests that

The release of potential energy due to downward movement of the building mass above the buckled columns exceeded the strain energy that could be absorbed by the structure. Global collapse ensued.

It implies that the building mass above the buckled columns (part C) must remain intact for the collapse (actually crush down) of lower structure (part A) to ensue.

Anybody who has done structural damage analysis of two similar bodies colliding knows that both bodies are locally damaged at first contact and that damages will be arrested after a while.

It seems NIST had never done a structural damage analysis, so you wonder why GWB asked them to do it. Why not ask real experts?

 

[Grizzly Bear]

Let's do some calculations. The drop releases 0.27 GJ of kinetic energy. It corresponds to less than two gallons of fuel. Where did you get 130 tons of TNT from?

For a 60 m long perimeter steel wall to slice a thin floor requires 0.03 GJ and for the core to do the same thing 0.02 GJ is required. Thus to slice one floor 0.08 GJ is required (only two perimeter walls slice). So it looks as if only 4 floors will be sliced; two in the upper part C and two in lower part A. Then all energy is consumed as local failures. Even without friction the collapse is arrested. And no rubble was produced.

See, I did it.

The mass of the entire top section of just the north tower alone when falling on the lower section in dynamic load was the rough equivalent of putting 8 g's worth of force on those floors. That's about the equivalent of adding an additional 80 stories or another building height to the weight which the individual floors had to carry. And that's calculating for a fall from one story, not 4 or 5 as was the case for the towers. I somehow doubt the welds and bolts on each of the floor connections is going to stop all of that additional loading. Somehow I don't think you understand that a structural system relies on the collective strength of all the smaller parts working together, but I'm sure this has been explained to you countless times...

 

[Architect]

Still no competent structural calculations from Heiwa, I see.

 

[Mel Odious]

Let's do some calculations. The drop releases 0.27 GJ of kinetic energy. It corresponds to less than two gallons of fuel. Where did you get 130 tons of TNT from?

For a 60 m long perimeter steel wall to slice a thin floor requires 0.03 GJ and for the core to do the same thing 0.02 GJ is required. Thus to slice one floor 0.08 GJ is required (only two perimeter walls slice). So it looks as if only 4 floors will be sliced; two in the upper part C and two in lower part A. Then all energy is consumed as local failures. Even without friction the collapse is arrested. And no rubble was produced.

See, I did it.

0.27 GJ, you say? Let's see what you're assuming the mass of the upper block to be. I'll take the "drop" to be 3.5 meters:

PE = mgh

m = PE/gh

m = 270,000,000/(9.8*3.5)

m = 7,871,720 kg

Or a bit less than 7,900 metric tons.

Is that close to the mass you're assuming the upper block to be? And if so, are you sure that figure might not be a little low? (OK, a lot low ...)

 

[Heiwa]

0.27 GJ, you say? Let's see what you're assuming the mass of the upper block to be. I'll take the "drop" to be 3.5 meters:

PE = mgh

m = PE/gh

m = 270,000,000/(9.8*3.5)

m = 7,871,720 kg

Or a bit less than 7,900 metric tons.

Is that close to the mass you're assuming the upper block to be? And if so, are you sure that figure might not be a little low? (OK, a lot low ...)

h = 0.5 m. Bazant talks about a drop of 0.5 m!

 

[beachnut]

Let's do some calculations.
See, I did it.

one floor assembly can only hold 26,000,000 pounds and that is just 11 floors extra. Then the floor fails and the next floor fails. etc. etc. etc.

You have failed.

kids on bed, fail
pizza boxes, fail
sponge, fail

Your ideas failed on 911. You apologize for terrorist who flew planes, the planes you say did not do 911.

Your delusions are noted. Your lack of knowledge must be politically motivated so you can support those who want to kill Americans, your terrorist friends you apologize for continuously by spewing delusions.

You are spewing the nut case ideas of 911Truth, and you try to couch it as engineering. Another delusion.

 

[Heiwa]

The mass of the entire top section of just the north tower alone when falling on the lower section in dynamic load was the rough equivalent of putting 8 g's worth of force on those floors. That's about the equivalent of adding an additional 80 stories or another building height to the weight which the individual floors had to carry. And that's calculating for a fall from one story, not 4 or 5 as was the case for the towers. I somehow doubt the welds and bolts on each of the floor connections is going to stop all of that additional loading. Somehow I don't think you understand that a structural system relies on the collective strength of all the smaller parts working together, but I'm sure this has been explained to you countless times...

You are simply wrong. What Bazant says (lies) is that the kinetic energy of the upper part exceeds 8X what one storey below can absorb = an 0.9 m layer of rubble is formed = crush down continues (and upper part C remains intact). But there are 97 storeys below that absorb the energy and then ... the upper part just bounces. No rubble is formed.

Evidently the upper part also absorbs energy (which Bazant forgets).

In reality the columns will slice the floors, etc.

It is quite easy to debunk Bazant. Everything he says/writes in his paper are lies.

Read my article about it.

I am glad to confirm that dropping a part of something on something will not crush something. There will just be local failures at contact. Or if something has homogeneous density, etc, it will be a bounce.