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WTC 1 & 2. What happened after collapse initiation?

Heiwa said:
What material falls in (?) to the floor below? Air?
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Whhhooooaaaa... Whoa. Tell me you don't believe that once the damaged floors gave way, the upper sections should have somehow been ejected out and away from the towers without ever touching the floors below...

Please...
 
No...

As near as I can figure, heiwa believes that if the columns of the upper section did not impact exactly on the columns of the lower section, then the upper section would have fallen through the lower section, stripping out the floors but leaving the frame intact and standing.
 
[X] said:
No...

As near as I can figure, heiwa believes that if the columns of the upper section did not impact exactly on the columns of the lower section, then the upper section would have fallen through the lower section, stripping out the floors but leaving the frame intact and standing.
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I... I'm not sure that's any better. Wow.
 
Have we all noticed that power-hitters like Newton's Bit, RWGuinn, Mackey, and others are done playing with Heiwa?
 
pomeroo said:
Uh, no. You are a spectacular incompetent.

Think again--r-e-a-l hard. You are saying that dropping thirty floors onto a floor designed to support one floor won't crush the structure. Think hard.
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Actually, if the first floor is dropping down from above for whatever reason, it would be sliced apart by the columns below and will not damage the primary structure below. Same for next 29 floors.

You see (probably not?), thin floors dropping down from the sky by gravity cannot damage solid primary structure, steel columns, below.

The floors can absorb very little strain energy when contacting a column and are therefore failing themselves. The columns below will remain in position, i.e. the Tower will not collapse. A floor cannot shear off a column. 30 floors cannot shear off a column. CD can shear off a column.

Think about it.
 
[X] said:
No...

As near as I can figure, heiwa believes that if the columns of the upper section did not impact exactly on the columns of the lower section, then the upper section would have fallen through the lower section, stripping out the floors but leaving the frame intact and standing.
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Almost right. Half the wall columns above will hit nothing as they are outside the building when dropping and the other half of wall columns are inside slicing the floors.

Only floors above will contact columns below, and as stated many times, the floors will fail. The columns below will remain.

After a while the locally damaged floors are jammed between the columns below and ... that's it. No global collapse! Just local failures up top.

Not so difficult to figure out.

I have a feeling Bazant & Co fooled you. But they are no real engineers.
 
​
Heiwa said:
Almost right. Half the wall columns above will hit nothing as they are outside the building when dropping and the other half of wall columns are inside slicing the floors.

Only floors above will contact columns below, and as stated many times, the floors will fail. The columns below will remain.

After a while the locally damaged floors are jammed between the columns below and ... that's it. No global collapse! Just local failures up top.

Not so difficult to figure out.

I have a feeling Bazant & Co fooled you. But they are no real engineers.
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Dr. Zdenĕk Bažant received his Ph.D. in Engineering Mechanics in 1963 from the Czechoslovak Academy of Sciences, Prague . He joined Northwestern University in 1969, became Professor in 1973, and served as the Director of Center for Geomaterials from 1981 to 1987. Since 1990, Dr. Bažant has been the Walter P. Murphy Professor of Civil Engineering and Materials Science. Beginning 2002 Professor Bažant has also been the McCormick School Professor.

Dr. Bažant’s research areas include structural engineering, concrete, geomaterials, facture, stability, creep damage in elastic behavior. He has authored over 430 journal articles and six books including most recently the Stability of Structures: Elastic, Inelastic, Fracture and Damage Theories (Oxford University Press) and Inelastic Analysis of Structures (J. Wiley & Sons).

Dr. Bažant is a registered Structural Engineer in Illinois . His honors and awards are numerous and most recently include the Lifetime Achievement Award from the ASCE Illinois Structural Engineering Section (2003), elected Member of the National Academy of Sciences, Washington, D.C. (2002), Foreign Member, Academia Di Scienze e Lettere – Istituto Lombardo, Milan Italy (2002), elected Member of the National Academy of Engineering, Washington, D.C. (1996) and five honorary doctorates from Universities in Colorado, Prague, Karlsruhe, Milan and Lyon.​

From: http://www.ce.jhu.edu/carroll-lectureship/2005Bazant.htm

I guess the Universities of Prague, Karlsruhe, Milan and Lyon are in on it too?
 
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Heiwa said:
Only floors above will contact columns below, and as stated many times, the floors will fail. The columns below will remain.
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I'm afraid that's totally false, the floors served partly as lateral bracing to both the perimeter columns and the core columns. Losing that lateral bracing significantly weakens the columns, the core columns couldn't even support their OWN weight after the structure yielded.


Heiwa said:
After a while the locally damaged floors are jammed between the columns below and ... that's it. No global collapse! Just local failures up top.
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Your premise is that the entire lower section of building is sustaining the load. While true, we're seeing this as a system, the column sections were over loaded one by one, not the entire system simultaneously. That's what a domino effect is, parts yield one after the other.
 
Newtons Bit said:
​

Dr. Zdenĕk Bažant received his Ph.D. in Engineering Mechanics in 1963 from the Czechoslovak Academy of Sciences, Prague . He joined Northwestern University in 1969, became Professor in 1973, and served as the Director of Center for Geomaterials from 1981 to 1987. Since 1990, Dr. Bažant has been the Walter P. Murphy Professor of Civil Engineering and Materials Science. Beginning 2002 Professor Bažant has also been the McCormick School Professor.

Dr. Bažant’s research areas include structural engineering, concrete, geomaterials, facture, stability, creep damage in elastic behavior. He has authored over 430 journal articles and six books including most recently the Stability of Structures: Elastic, Inelastic, Fracture and Damage Theories (Oxford University Press) and Inelastic Analysis of Structures (J. Wiley & Sons).

Dr. Bažant is a registered Structural Engineer in Illinois . His honors and awards are numerous and most recently include the Lifetime Achievement Award from the ASCE Illinois Structural Engineering Section (2003), elected Member of the National Academy of Sciences, Washington, D.C. (2002), Foreign Member, Academia Di Scienze e Lettere – Istituto Lombardo, Milan Italy (2002), elected Member of the National Academy of Engineering, Washington, D.C. (1996) and five honorary doctorates from Universities in Colorado, Prague, Karlsruhe, Milan and Lyon.​

From: http://www.ce.jhu.edu/carroll-lectureship/2005Bazant.htm

I guess the Universities of Prague, Karlsruhe, Milan and Lyon are in on it too?
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I am always suspicious about an engineer producing 430 articles about various matters and doesn't know about collapse arrest of steel structures.
And to produce the WTC article only two days after the destructions is too quick. I doubt Bazant has ever worked in industry or insurance and analysed failed structures. Seems he spent most time in the ivory tower. Does any of the 430 articles and six books mention collapse arrest or analyse any other structural failures of steel structures/buildings?
 
Grizzly Bear said:
I'm afraid that's totally false, the floors served partly as lateral bracing to both the perimeter columns and the core columns. Losing that lateral bracing significantly weakens the columns, the core columns couldn't even support their OWN weight after the structure yielded.
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If you re-read my article, you see that the floors (secondary structure) are only failing at one edge, i.e. your 'bracing' is intact at the other side, etc, etc. No primary structure (columns) will fail due to that.
You are not back to the pan-caking nonsense where floors are disconnected from the columns all around their edges?

The core columns are assumed only failing in one location (the initiation zone) due to heat. The core below is not affected by that in any way except being unloaded by the core column forces above, that are now destroying the floors as previously described. Nothing can destroy the primary core structure (the columns) below the initiation zone!
 
Heiwa said:
I am always suspicious about an engineer producing 430 articles about various matters and doesn't know about collapse arrest of steel structures.
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Yeah .... those famous engineers, eh?? Gah! What can you do with 'em, not knowing as much as a ship's welder about the collapse of massive steel-framed buildings??? What a bunch of losers.
 
Heiwa said:
Actually, if the first floor is dropping down from above for whatever reason, it would be sliced apart by the columns below and will not damage the primary structure below. Same for next 29 floors.

You see (probably not?), thin floors dropping down from the sky by gravity cannot damage solid primary structure, steel columns, below.

The floors can absorb very little strain energy when contacting a column and are therefore failing themselves. The columns below will remain in position, i.e. the Tower will not collapse. A floor cannot shear off a column. 30 floors cannot shear off a column. CD can shear off a column.

Think about it.
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That thought would require far too many recreational drugs.
 
Grizzly Bear said:
Your premise is that the entire lower section of building is sustaining the load. While true, we're seeing this as a system, the column sections were over loaded one by one, not the entire system simultaneously. That's what a domino effect is, parts yield one after the other.
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Really? (Have you read my article?).

My first premise is that the potential energy released at initiation is absorbed 50/50 by lower structure and upper block structure as both parts have equal capabilty to absorb energy. No domino effect! Just a collision of structures.
NIST & Co assume wrongly that all energy is only transmitted into the lower structure - crush down - and that upper block acts as a hammer head (where the energy is stored)!

My second premise is that the potential energy released is absorbed by local failures (overload) in secondary structure (floors) only and by friction between displaced parts in contact and shifting load patterns. The floors are located both in the upper block and lower structures. The first floors to start absorbing energy are evidently the nearest ones above and below the initiation zone.

My third premise is that primary structure (columns) below are not affected at all by the release of potential energy (as described in my articles). Reason is of course that the energy released is not applied to this primary structure below! How can you write that the columns are overloaded one by one? Look at the figure in my article. Evidently the primary structure (columns) below will be loaded more or less as before after collapse arrest! The load of what remains of the upper block is transmitted to the columns below via the damaged floors jammed there.

My fourth premise is that the upper block structure is severly damaged by the absorbtion of energy. In the worst case two outer walls would have sheared off completely and dropped down on the outside in one big piece as débris. As this didn't happen the destruction was not caused by release of potential energy. Another smoking gun?

My fifth premise is that the release of potential energy and absorbtion of this energy as described above will not produce any big amounts of rubble (pieces of cement of the floors, etc). Reason is that the floors that lose their connections at one edge will only hinge down and jam on other floors inside the structure below. The floors will not pulverize, etc. The big amount of rubble produced cannot have been caused by release of potential energy.

How could you misunderstand me so completely?

FYI - I just try to assist NIST to get its report right! Hopefully Shyman Saunder, PhD at NIST, is working on that right now.

He is actually one of my peer reviewers!
 
Heiwa said:
Really? (Have you read my article?).
My first premise is that the potential energy released at initiation is absorbed 50/50 by lower structure and upper block structure as both parts have equal capabilty to absorb energy. No domino effect! Just a collision of structures.
NIST & Co assume wrongly that all energy is only transmitted into the lower structure - crush down - and that upper block acts as a hammer head (where the energy is stored)!
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This is like assuming that the entire building is a solid object, once again. NIST has already pointed out that the floors could not could not sustain more than 6 floors worth of dynamic load. As I keep telling you, the floors may have offered resistance to the fall but there's an entire floor height of space between each floor that the debris and material would fall through if the floor below was unable to sustain the load. Any momentum lost by that resistance would be regained and then some and proceed to the next intact floor. That is a domino effect, one collapse event leads to another, and another.


Heiwa said:
How can you write that the columns are overloaded one by one? Look at the figure in my article. Evidently the primary structure (columns) below will be loaded more or less as before after collapse arrest!
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The columns were not continuous pieces of steel, they were each an assembly consisting of 3-story sections. Most, failed at the connections where the columns continued. The structure is worthless if the connections are not able to arrest the load being applied to them, basic principal.


Heiwa said:
My fourth premise is that the upper block structure is severly damaged by the absorbtion of energy. In the worst case two outer walls would have sheared off completely and dropped down on the outside in one big piece as débris. As this didn't happen the destruction was not caused by release of potential energy. Another smoking gun?
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What?
In other words you're stating that the only parts that should have collapsed in the worst case is the perimeter columns? The planes punched right through them. The interior of the towers was essentially open space between the perimeter columns and the core columns. Lots of room for plane debris to cause damage, let's not forget the fires that ensued... That's certainly no smoking gun


Heiwa said:
How could you misunderstand me so completely?
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I can't say I ever have understood your argument completely, nor am I the most qualified critic. But the parts which I understand most clearly make no sense in the context of the collapse... the damage to the towers was never restricted to the exterior, as your 4th premise (unintentionally?) implies... I'm not even sure what you mean by that either. Since the loads over the gap made by the planes weren't simply 'hanging' from the very top of the towers, the loads were being bridged over to the nearest in-tact exterior columns...
 
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