Moderated Steel structures cannot globally collapse due to gravity alone

Heiwa,



Nah, this is completely wrong.

Why do you consistently, deceptively group the damaged & weakened 6 floors in with the undamaged upper Part C? This is simply wrong.

The initial collapse happens within part D, the weakened floors. Not in Part A OR in Part C.
The crush damage in Part D DOES happen both upwards & downwards.



Nah, you're completely wrong here, too.

Part D is about 6 floors thick. By the time that it has almost crushed, Part A & Part C are still ALMOST untouched. And by the time upper Part C has descended say 3 stories, gathering up 3 stories of rubble, the bottom portion of Part C is completely packed in with debris of Part D.

By the time upper Part C with Part D debris packed in reaches the top of Part A, it is essentially solid on the bottom surface. As a direct result of this, ONLY lower Part A will be destroyed.

JUST LIKE we saw on 9/11.



Nah, this is all wrong. I've explained it above.



Nope. See above.



Well, almost. Part B is accelerated by BOTH gravity & Part C.



Nah, the NWO are like you. They don't know physics either. By the way, this has very little to do with physics. (This is why Steven Jones is stumbling around so helplessly.) It is engineering.



That's true. No fully laden passenger jets had been intentionally flown into 110 story skyscrapers prior to 9/11.



Common sense will actually go a long way to understanding what is going on. You should try it some time.

Rather than resorting to unsupported assertions, and flawed papers over at Heiwaco, why don't you address my simple assertions in this post?

tom

I see that you now suggest a new A, B, C, D theory. Pls inform NIST, Bazant, Seffen & Co and they will assist you with the relevant differential equations. Or build a model with some suitable structure demonstrating it.

Poor A now being crushed by B, C and D! I still maintain that A will damage B, C and D and that A is the winner.
 
Heiwa,

I see that you now suggest a new A, B, C, D theory. Pls inform NIST, Bazant, Seffen & Co and they will assist you with the relevant differential equations. Or build a model with some suitable structure demonstrating it.

Poor A now being crushed by B, C and D! I still maintain that A will damage B, C and D and that A is the winner.

I see that you are capable of making snarky remarks, and yet strangely unable or unwilling to discuss the pertinent engineering issues associated with my comments.

By the way, I did NOT suggest a new theory here. If you had bothered to read NIST's report and Bazant's papers, they specify EXACTLY the same situation that I did when describing the towers before collapse: an intact lower section (your Part A), an intact upper section (the upper portion of your Part C) and a damaged group of floors joining the two (the part that you ignore & that I am referring to as Part D).

This is not a trivial mistake, Anders. This is crucial to the analysis.

Is there any particular reason that you ignored both NIST's & Bazant's models?

Is there some reason that you placed those damaged 6 floors into Part C, Anders?

Is it your custom when constructing models to group together parts (in this case your Part C) that have completely different physical characteristics?

Would you care to comment on the debris "packing into" the descending Part C?

Would you care to comment on the fact that your statement seems to imply that debris has no weight?

Would you care to comment on the fact that the lattice structure of the towers is completely unstable if it is not crossbraced?

Would you care to comment on the impact of the staggered core & peripheral columns, and the resultant damage done to 2/3rds of each floor's support before the descending mass arrives at that floor?

One final note: Please spare me the reference back to your paper. I've already read it. And found it woefully riddled with errors.

regards,

tom
 
Heiwa,



By the way, I did NOT suggest a new theory here. If you had bothered to read NIST's report and Bazant's papers, they specify EXACTLY the same situation that I did when describing the towers before collapse: an intact lower section (your Part A), an intact upper section (the upper portion of your Part C) and a damaged group of floors joining the two (the part that you ignore & that I am referring to as Part D).

regards,

tom

You really have to read the BLGB paper - part C crushing part A (both of uniform density 0.25) and in the process producing part B (rubble with density 1.0 of what was previously the top of part A while part C is undamaged). Evidently part B is not joining parts A and C. It is a cushion of rubble that is 4 times more dense than both parts A and C and accelerating!

It is like compressing three lemons A, B and C in line! Force is applied on A and C and only B is compressed ... and accelerated. If you can do that in the real world of lemons, you'll win a prize.
 
Heiwa,

I see that you now suggest a new A, B, C, D theory. Pls inform NIST, Bazant, Seffen & Co and they will assist you with the relevant differential equations. Or build a model with some suitable structure demonstrating it.

Poor A now being crushed by B, C and D! I still maintain that A will damage B, C and D and that A is the winner.

As I mentioned in the post above, I have suggested nothing different from BLGB's or NIST's analysis.

If you were to follow your own advice & read BLGB paper carefully, you will notice that in Figure 1, the left most, lower figure shows the towers before collapse. This figure has THREE xones defined.

Zone A (BLGB) corresponds to your Part A.
Zone C (BLGB) is the upper, undamaged segment.
Zone So is the damaged 6 stories, the zone that you ignore, and the one that I referred to as Part D.
Zone B is the crushed down Zone So.

You have combined BLGB's Zone C & Zone So into your ONE Part C.

The direct result of this sloppiness is that you have produced two serious descriptive errors and numerous analytical ones.

The first is to combine two areas of the towers that have completely different material properties and structural integrity (BLGB's Zones C & So) into your one Part C. This is VERY POOR engineering practice.

After having been pointed out to you several times, the second error is a misrepresentation that is so egregious that it has become intentional deception. You have repeatedly stated that "Bazant claims that Part C is rigid and therefore is undamaged while crushing down Part A."

Bazant recognizes that the initial crush happens in Zone So. It is YOU, Anders, that has erroneously forced BLGB's Zone So to become a component of your Part C. IF Bazant were to agree to join his Zones C & So into one piece (which of course, he would not), THEN his analysis would CLEARLY conclude that the initial crush down did happen in Part C. NOT that Part C remained undamaged while crushing down Part A.

Of course, the correct solution is for you to cease making the egregious error of joining Zones C & So into one Part C.

And to issue a retraction of your misrepresentations of Bazant's assertions.

Are you honest enough to do this?

tom
 
Heiwa,



As I mentioned in the post above, I have suggested nothing different from BLGB's or NIST's analysis.

If you were to follow your own advice & read BLGB paper carefully, you will notice that in Figure 1, the left most, lower figure shows the towers before collapse. This figure has THREE xones defined.

Zone A (BLGB) corresponds to your Part A.
Zone C (BLGB) is the upper, undamaged segment.
Zone So is the damaged 6 stories, the zone that you ignore, and the one that I referred to as Part D.
Zone B is the crushed down Zone So.

You have combined BLGB's Zone C & Zone So into your ONE Part C.

The direct result of this sloppiness is that you have produced two serious descriptive errors and numerous analytical ones.

The first is to combine two areas of the towers that have completely different material properties and structural integrity (BLGB's Zones C & So) into your one Part C. This is VERY POOR engineering practice.

After having been pointed out to you several times, the second error is a misrepresentation that is so egregious that it has become intentional deception. You have repeatedly stated that "Bazant claims that Part C is rigid and therefore is undamaged while crushing down Part A."

Bazant recognizes that the initial crush happens in Zone So. It is YOU, Anders, that has erroneously forced BLGB's Zone So to become a component of your Part C. IF Bazant were to agree to join his Zones C & So into one piece (which of course, he would not), THEN his analysis would CLEARLY conclude that the initial crush down did happen in Part C. NOT that Part C remained undamaged while crushing down Part A.

Of course, the correct solution is for you to cease making the egregious error of joining Zones C & So into one Part C.

And to issue a retraction of your misrepresentations of Bazant's assertions.

Are you honest enough to do this?

tom

Hm, I use BLGB Fig 2 bottom second left - Crush down phase + text in article, where everything is as I copy it. Part C (top part), 'zo', tall crushes a slice thickness 'so' of intact part A below and compresses this part of A into part B 'lambda so' thick (density of part B 4X density of A and C). Part C remains intact, 'zo' tall, all time.

In fig. 2 middle figure - Crush up Phase, we can then see how part B crushes up part C, still 'zo' tall before crush up from below.

All nonsense, of course, but this is what BLGB believe.

Please, read the BLGB paper and look at the figures. They are a joke!
 
I did. In the picture I posted you get a ground level perspective, not from above as in the video you posted. As you can see, the water is spraying where that section of the bldg collapsed and was halted by the two story section at ground level.

No. Your ridiculously poor photo only shows the facade of the outcropping at the bottom of the structure which obstructs the view of the collapsed section. You have no idea what the building even looks like, apparently. Here it is again, pay attention:


Now look at approx. 0:42 of this video:



You can see the collapsed floors below the level of the two outcropping sections on either side. The previous video clearly shows this as well.

And here at approx. 0:33 you can see collapsed floors behind the rubble resting on top of the outcropping (select HQ for a better view):



What will your next excuse be?
 
I did. In the picture I posted you get a ground level perspective, not from above as in the video you posted. As you can see, the water is spraying where that section of the bldg collapsed and was halted by the two story section at ground level.

The WTC buildings collapse did not propogate all the way to ground level.
 
Heiwa,

Now we're finally getting somewhere, Anders. It's amazing how much progress can be made if you actually say something other than "ditto last piece of nonsense" and "read my papers".

Of course, since the progress is showing you to be lying about Bazant's paper and now reversing everything that you've said previously, you might not consider it progress...

Hm, I use BLGB Fig 2 bottom second left - Crush down phase + text in article, where everything is as I copy it.

First, let's make sure we are using the same paper. I am referring to BLGB "Collapse of World Trade Center Towers: What Did and Did Not Cause It?" http://www.civil.northwestern.edu/p...TC Collapse - What Did & Did Not Cause It.pdf

Here is Bazant's figure. It is his Figure 1, not Fig. 2.

album.php


If this image doesn't post, you can see it here: http://www.internationalskeptics.com/forums/album.php?albumid=176&pictureid=803

And Bazant says:
Bazant said:
During the crush-down phase, the moving upper part of tower (C in Fig. 1 bottom), with a compacted layer of debris at its bottom (zone B), is crushing the lower part (zone A) with little damage to itself, except before a thick enough layer B of debris forms).
[Emphasis added.]

It is perfectly clear from this figure and the text above that he does NOT include Zone So or Zone B in the lower Zone A.
It is perfectly clear from this figure and the text above that he does NOT include Zone So or Zone B in the upper Zone C.

So, your statement that "everything [of BLGB] is as I copy it" is patently false. You should correct your misstatement.
___

Your second, repeated misportrayal of Bazant's statements is saying that Bazant claims that "Part C suffers no damage as it crushes Part A".

Note the bolded words in Bazant's paper above. This sentence explicitly says that Bazant recognizes that damage WILL be done to Part C. Especially early in the crush down process.

Your claim to the contrary is shown to be false. You should correct your erroneous portrayal of Bazant's stated opinion.


Part C (top part), 'zo', tall crushes a slice thickness 'so' of intact part A below and compresses this part of A into part B 'lambda so' thick (density of part B 4X density of A and C). Part C remains intact, 'zo' tall, all time.
[Emphasis added]

And now, you are intentionally saying the exact opposite of what you have asserted all along.

You have CONSISTENTLY and erroneously included the damaged floors in upper Part C. You do it in your "papers", you do it in your illustrations, and you do it in your text.

For example, in your "911 & WTC collapse" paper ( http://heiwaco.tripod.com/nist.htm ), your previous version of that page has the section entitled "Part I - NIST explains Something", you explicitly include the damaged floors in the upper Part C.


album.php


If this image doesn't post, you can see it here: http://www.internationalskeptics.com/forums/album.php?albumid=176&pictureid=804

You state: "The upper part of WTC 1 is above the yellow line applied on the photos of the WTC 1 tower at say floor 93 and the lower structure is below." The damaged floors were from 93 to 98.

"You can slide the video fwd/aft and see how the upper part is destroyed first, while everything below remains intact as shown below"

In the current version of this same webpage, you state the same thing:

First that Bazant claims that they are indestructible: "The upper parts of WTC 1, 2 are the problems. They are according Bazant/Seffen ... supposed to be rigid, stiff, solid, of uniform density, indestructible, with infinite strain energy, SEa".

And second, that the upper Part C fails first: "All videos of the destruction show that the upper part in fact telescopes into or shortens itself for 2-4 seconds, while the steel structure below is still intact!" and "At WTC 2 the upper part disappers in a dust cloud before the lower structure is affected." and "No intact upper parts (4) are seen during the destructions that followed. In the case of WTC2 the upper part explodes outside the footprint of the tower. It was not very rigid!"

In EACH of these sentences, and in all your illustrations, you have CLEARLY included the damaged floors in the upper Part C of the towers.

But NOW you are reversing yourself. You are now saying, in the bolded text in your reply above, that the damaged floors (that will become Part B) are part of the lower Part A segment.
___

In conclusion:
1. You have repeatedly misstated Bazant's description of his model. He has 3 initial segments. You have claimed that he had only 2.
2. You have misstated Bazant's statement of the damage that occurs to Part C. He explicitly says that Part C WILL suffer damage. You have claimed that he said the opposite.
3. You are now reversing everything that you have said previously about the location of the damaged floors in your model. In all your previous analyses, you placed those floors in Part C. Now you are placing them in Part A.

Get your story straight, please. Clean up your analysis by acknowledging a separate Part D, as NIST and Bazant do.
And issue a retraction regarding your erroneous mis-portrayals of NIST's and Bazant's positions.


tom
 
In my BLGB paper (same as yours):

List of Figures
1 Scenario of column force redistribution after the aircraft impact . 20
2 Top: Scenario of collapse. Bottom: Crush-down and crush-up phases of collapse; A–intact stationary (lower) part, B–dense layer of crushed debris, C–intact moving (upper) part. . . . . . . . . . . 20

So fig. 2 is fig. 2! Not fig. 1!

The BLGB paper, page 3, makes reference to this fig 2, bottom part:

The gravity-driven progressive collapse of a tower consists of two phases—the crush-down, followed by crush-up (Fig. 2 bottom), each of which is governed by a different differential equation (Bazant and Verdure 2007, pp. 312-313). 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. During the crush-up, the moving upper part C of tower is being crushed at bottom by the compacted debris B resting on the ground.

According Bazant, I repeat: 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.

Your quote is slightly different (but you do not find your quote it in the BLGB paper).

Sorry, when I quote Bazant I do it copy/paste. When I describe what Bazant says I do it correctly. What Bazant suggests is pure nonsense. As I describe in my article.
 
I find it quite amazing that nobody is able to produce a structure of any kind and any size where an upper part C of this structure can crush part A of same structure when dropped on A (C = 1/10 A). There is now 50 pages to this thread.

Where is the problem?
 
Heiwa,

In my BLGB paper (same as yours):

List of Figures
1 Scenario of column force redistribution after the aircraft impact . 20
2 Top: Scenario of collapse. Bottom: Crush-down and crush-up phases of collapse; A–intact stationary (lower) part, B–dense layer of crushed debris, C–intact moving (upper) part. . . . . . . . . . . 20

So fig. 2 is fig. 2! Not fig. 1!

The BLGB paper, page 3, makes reference to this fig 2, bottom part:

The gravity-driven progressive collapse of a tower consists of two phases—the crush-down, followed by crush-up (Fig. 2 bottom), each of which is governed by a different differential equation (Bazant and Verdure 2007, pp. 312-313). 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. During the crush-up, the moving upper part C of tower is being crushed at bottom by the compacted debris B resting on the ground.

According Bazant, I repeat: 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.

Your quote is slightly different (but you do not find your quote it in the BLGB paper).

Sorry, when I quote Bazant I do it copy/paste. When I describe what Bazant says I do it correctly. What Bazant suggests is pure nonsense. As I describe in my article.

All right. Bazant has revised his paper. I had been referring to the previous revision.

But, hot dang, look what he added. A section & an appendix that address our question specifically.

Bazant said:
The fact that the crush-up of entire stories cannot occur simultaneously with the crush-down is demonstrated by the condition of dynamic equilibrium .... It is found that, immediately after the first critical story collapses, crush fronts will propagate both downwards and upwards. However, the crush-up front will advance into the overlying story only by about 1% of its original height h and then stop. Consequently, the effect of the initial two-way crush is imperceptible and the hypothesis that the crush-down and crush-up cannot occur simultaneously is almost exact.

And in the appendix, after a detailed analysis, Bazant concludes:

Bazant said:
Appendix. Can Crush-Up Proceed Simultaneously with Crush-Down?
Since the initial crush-up phase terminates at very small axial deformation, it must be concluded that the simplifying hypothesis of one-way crushing is perfectly justified and causes only an imperceptible difference in results.

I'll read thru this new (to me) material & get back to you in the next couple of days. While I'm reading this, why don't you post exactly what you think Dr. Bazant got wrong in his equations or solutions. Please be rigorous, avoid arguments that depend on prose & show your math.

tom
 
I'm still waiting on Bazant's model....

50 pages here, 8 years there.

Bazant (the magnificent fudger) is free to continue changing his theories at will it seems. How about he just builds a model and prove it?

Oh wait....NIST already tried that.

Utter fail.
 
Oh NO! Bazant tweaked his theory so [insert idiotic other theory here] MUST be true!
 
Heiwa,



All right. Bazant has revised his paper. I had been referring to the previous revision.

I'll read thru this new (to me) material & get back to you in the next couple of days. While I'm reading this, why don't you post exactly what you think Dr. Bazant got wrong in his equations or solutions. Please be rigorous, avoid arguments that depend on prose & show your math.

tom

Tom! :)

Bazant (in BLGB paper Appendix we now have same copy of) suggests:

Since the initial crush-up phase terminates at very small axial deformation, it must be concluded that the simplifying hypothesis of one-way crushing is perfectly justified and causes only an imperceptible difference in results.

This is not in accordance with my axiom. One way crushing does not happen anywhere in any structure, where a upper part C of it contacts a lower part A of same, identical structure after gravity drop.

One way crushing is just another excuse to keep upper part C rigid. As it is not the case equation (1) of the BLGB paper is not valid.

Or for my kid audience. When part C drops and contacts part A, it does not produce a rubble part B only of part A as assumed by Bazant. Part B is also rubble of part C.
Replace rubble part B by what it is: local failures of structure of parts C and A and you understand.
So with this adjustments part C will be destroyed before part A exactly as per my axiom.
 
50 pages here, 8 years there.

Bazant (the magnificent fudger) is free to continue changing his theories at will it seems. How about he just builds a model and prove it?

Oh wait....NIST already tried that.

Utter fail.


Do you have a superior model that you'd like to present?
 
There is now 50 pages and almost 2000 posts on this thread and nobody has been able to disprove that steel structures cannot globally collapse due to gravity alone even if your drop a part C of the structure A on it (C=1/10A and was carried by A before). Reason is that steel structures are pretty strong.
Of course, WTC 1 was not just steel - the floors contained concrete - so it was a composite structure - but it is also difficult to destroy by gravity. Especially when the primary lodad bearing structure - the columns - is steel.
Some people suggest that steel gets weaker, if you scale it up ... but sorry! You cannot scale steel! It is the same at any scale!
Same people suggest that a steel structure gets weaker, if you scale it up ... but sorry! If you scale up something you have to adjust many parameters to maintain strength... so strength is constant.
And when strength is constatnt, scale or size doesn't matter. Drop C on A in any size/scale and C never destroys A before it destroys itself.

No doubt about it.

But I look forward to another 2000 posts trying to show I am wrong.

Heiwa
 
Some people claim that the phenomenas observed in the destruction of the
twin towers (steel beams hurled outwards etc) CAN be explained as the result of a gravitational collapse, however i have never heard anybody claim that it would NOT
be consistent with an explosive process.

Now, let us assume that the port authority would declare that they are going to demolish
the towers and evacuate Manhattan. A traditional demolition would not be suitable for
these slender buildings, so instead they will place explosives at every third
floor or so, and then detonate them in sequence from top to bottom.

Would this demolition look any different from what we saw on 9/11?

Would the result be any different?

Should we NOT expect debris to be ejected out and uppwards,
NOT expect a wide debris field with relatively little debris at the footprint, NOT expect
the content of the building to be pulverized or blown to small pieces?
(And had there been people in the buildings, we would NOT expect them to be blown
into little pieces)

However, if you say that all of the above is what we might expect, had there actually been explosives in the towers, are you then saying that there is no difference between
an explosive process, or whatever we might call it, and a progressive collapse?

Did the towers "auto explode" due to gravity?

(The way some of the victims bodies were desintegrated into small body parts, like a toe, an eye bulb, small pieces of bones etc is a topic in itself, would a collapse make
small pieces of your bones jump out of your body, out of the building and land on the roof of an adjecent building?)
 

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