Moderated Steel structures cannot globally collapse due to gravity alone

[e^n]

Personally, I'm just waiting on the Great Bazant's model to prove to the world that indeed a closed model total progressive collapse is possible....MINUS the foot of God, of course.

It already has, in fact it was proven with an even simpler model 2 days after 911 occured. This latest paper is simply a much refined version taking into account many additional factors. The result is that 'Gravity Powered' collapse is shown to be plausible with a wide range of initiating conditions.

To help you understand this, I gave you a very simple experiment to conduct earlier in the thread, much like I gave Christopher7 one. Have you conducted this? If not, why not?

Do you already know what would happen? I doubt it as you have made statements to the contrary, but if you are not willing to test your ideas and prove yourself wrong, you are limited to simply denying the reality.

I'm more than happy to explain everything I understand about 911 to you, and I will even go and do research on your behalf if I must. If your intention however is simply to read what I say, and then stick your fingers in your ears and shout about how it's still impossible and nothing proves it, then I have no interest in continuing.

Please, address the points I posted, attempt the experiment I suggested, or concede the point. Hyperbole and denial does not become you.

 

[Baylor]

Personally, I'm just waiting on the Great Bazant's model to prove to the world that indeed a closed model total progressive collapse is possible....MINUS the foot of God, of course.

Uh, do you realize that a controlled demolition is a progressive collapse?

 

[Architect]

Amazing; three more pages and still no structural calculations from Heiwa the "engineer", likewise two moe pagesw and C7 avoiding my question about why he beleives the likes of NB's qualifications/expertise to be bogus. Hey Chris, I note you don't accuse me of this again!

 

[Heiwa]

It already has, in fact it was proven with an even simpler model 2 days after 911 occured. This latest paper is simply a much refined version taking into account many additional factors. The result is that 'Gravity Powered' collapse is shown to be plausible with a wide range of initiating conditions.

To help you understand this, I gave you a very simple experiment to conduct earlier in the thread, much like I gave Christopher7 one. Have you conducted this? If not, why not?

Do you already know what would happen? I doubt it as you have made statements to the contrary, but if you are not willing to test your ideas and prove yourself wrong, you are limited to simply denying the reality.

I'm more than happy to explain everything I understand about 911 to you, and I will even go and do research on your behalf if I must. If your intention however is simply to read what I say, and then stick your fingers in your ears and shout about how it's still impossible and nothing proves it, then I have no interest in continuing.

Please, address the points I posted, attempt the experiment I suggested, or concede the point. Hyperbole and denial does not become you.

Bazant has written three papers about WTC 1.

Opus I - Why Did the World Trade Center Collapse? - Simple Analysis (Zdenek P. Bazant, F.ASCE, and Yong Zhou (2001))

Opus II - Mechanics of Progressive Collapse: Learning from World Trade Center and Building Demolitions (Zdenek P. Bazant, F.ASCE, and Mathieu Verdure (2007))

Opus III - What Did and Did not Cause Collapse of WTC Twin Towers in New York (Zdenek P. Bazant, Jia-Liang Le, Frank R. Greening and David B. Benson (2008))

In opus I the upper part (floor 97 – roof) drops free fall as a rigid body 3.6 m and impacts the lower part top storey – floor 96 - and produces a shock wave and columns break below floor 96; floor 96 + upper part then drop free fall again and impact floor 95 – columns break below floor 95, etc. Upper part and its bottom floor 97 remain intact all the time. It is assumed to be a rigid body. Its velocity increases all the time from 0 – 60 m/s, as acceleration is constant, say 0.7 g (g =9.8 m/s²).

In opus II upper part needs only to drop 0.5 m on floor 96 and then it is suggested that columns below floor 96 fail as described in opus I. Upper part remains intact all the time.

In opus III upper part drops as outlined in opus I and II, impacts floor 96 and compresses it and columns below into a 0.9 m thick layer of rubble (density 1 025 kg/m3). Then upper part + rubble layer impacts floor 95 that becomes a new0.9 m thick layer of rubble. It is repeated 95 times and the layer of rubble increases to 85.5 m thickness. It is the rubble layer + upper part that drive the crush down. The rubble layer acts as a piston and compresses also the air in the storey below so that air and some parts in the rubble can be ejected sideways. Then the 85.5 m rubble layer penetrates 22 m down into the basement (it is also compressed) and crush down is arrested by ground. Then the rubble layer is compressed more so it becomes really solid, so that the upper part (rigid during crush down) can be destroyed in a crush up. Nothing remains of the structure except rubble on the ground.

What is basically wrong with opus I-III is that they assume that the upper part and floor 97 remain intact as a rigid body until crush up. Furthermore the alleged crush down does not tally with what is seen on any videos of the destruction. Furthermore, the upper part + rubble cannot simply accelerate at 0.7 g and crush down/compress structure at the same time. Then only 30% of the potential energy is available to crush/compress a storey into a 0.9 m thick layer of rubble and it is much too little.

What you would expect, assuming the upper part and floor 97 drop and impact floor 96, is that also the upper part and floor 97 is compressed, e.g. using the terms of Bazant, crush up of upper part commences already at first impact. Thus, upper part would soon be rubble.
In reality, as ascertained by many collisions of steel structures, the stronger sub-parts of both bodies destroy the weaker sub-parts and after a while all energy applied is consumed as local failures and friction between damaged and intact entangled sub-parts.

Applying the structural damage analysis methods of, e.g., Development of progressive Collapse Analysis Procedure and Condition Assessment for Structures (Professor Ted Krauthammer, Protective Technology Center, The Pennsylvania State University, Robert L. Hall, PhD, Stanley C. Woodson, PhD, James T. Baylot, PhD, John R. Hayes, PhD, US Army Engineer Research and Development Center, Young Sohn, PhD, Defense Threat Reduction Agency), you will find that any destruction due to a loose top part of WTC 1 would be arrested after a few meters drop. The top part should have got stuck up top among a lot of local failures. Reason is that you cannot crush a steel structure by a part of the same steel structure only assisted by gravity.

So Bazant's opus I-III are as valid as a three dollars bill!

 

[Heiwa]

Amazing; three more pages and still no structural calculations from Heiwa the "engineer", !

Simple reason being that they are available in my articles on my popular web site. Copy/paste yourself as you like!

 

[e^n]

Heiwa, I appreciate your comments, but I don't find your claim to be that compelling. Why is it that you have ignored my previous posts repeatedly?

Please answer the questions I addressed to you, and we may discuss things from there.

 

[Heiwa]

Heiwa, I appreciate your comments, but I don't find your claim to be that compelling. Why is it that you have ignored my previous posts repeatedly?

Please answer the questions I addressed to you, and we may discuss things from there.

Pls, repeat the questions!

 

[e^n]

Heiwa: http://www.internationalskeptics.com/forums/showpost.php?p=4443129&postcount=484

edit: And a response here: http://www.internationalskeptics.com/forums/showpost.php?p=4446884&postcount=588

 

[Heiwa]

Heiwa: http://www.internationalskeptics.com/forums/showpost.php?p=4443129&postcount=484

edit: And a response here: http://www.internationalskeptics.com/forums/showpost.php?p=4446884&postcount=588

No questions there! Comments, yes. What is not clear to you?

 

[e^n]

No questions there! Comments, yes. What is not clear to you?

Where you and I differ is not clear.

We both agree that damaged columns do not hold much load, and that a damaged floor results in a fall through the same height as caused the previous damage.

Why do you not believe that this collapse could become progressive? If it has all the elements of being self sustaining, and you agree that you do not expect a 'failed' floor to hold load, then I can see no area whereby you may claim a progressive collapse is impossible.

How do you manage this?

 

[Heiwa]

Where you and I differ is not clear.

We both agree that damaged columns do not hold much load, and that a damaged floor results in a fall through the same height as caused the previous damage.

Why do you not believe that this collapse could become progressive? If it has all the elements of being self sustaining, and you agree that you do not expect a 'failed' floor to hold load, then I can see no area whereby you may claim a progressive collapse is impossible.

How do you manage this?

A column can carry a certain load and not buckle! Is that load exceeded, the column buckles! The load it carries then displaces down - the interface changes. That is an initial failure.
Column buckling is often a three hinges plastic deformation phenomenon - kneeling - without fractures. The column ends are often still attached to adjacent structure top and bottom.

Thus, after buckling, the load from above will still pass through the now buckled column and be transmitted to structure below. No free fall will occur.
Say that the load is first transmitted to the knee of the column that is now in contact with the floor of the structure below. The force in the column is known.
The buckled column + its load (actually the force) may then punch a hole in the floor. That is a second local structural failure (that absorbs energy and starts to arrest further failures). If the floor is strong enough further failures are prevented already then.
If the column buckles outside the building, the column knee will not contact anything at all. The load on the column will drop outside.
Thus, you have to analyse the damages development step by step, keep track where the loads/forces are transferred and what failures they may cause, energy applied (force x distance) and absorbed, etc., etc.

Re WTC 1 I doubt very much that any columns in the initiation zone buckled at all due to fire/heat (as explained in my articles). And if it had happened the load above would soon be carried through buckled columns via new contact areas on floors (that might have suffered damages) and after that destruction would be arrested.

However, as I observe in my articles the upper part - the load - seems to self-destruct (CD!) prior to any buckling of columns below.

So what you see later is not some sort of progressive collapse or crush down by further CD!

The Bazant model - opus I, II & III - cannot be seen on any videos. The upper part and the rubble supposed to drive the crush down are not there!

And the Bazant rubble with density 1025 kg/m3 (mostly air) cannot destroy any columns. But the rubble layer is not there.

The rubble is not there! It is ejected sideways like a fountain by the energy provided by the CD to destroy the structure below - progressively from top to bottom.

The crime of the century was done in front of millions of people - and they were told it was ... just progressive collapse.

Sorry, I disagree. It was CD.

 

[Dave Rogers]

Self-debunking by Christopher7:

I don't know how the molten steel remained molten, only that it did.

I don't know how thermite was used.

Wrong! You cannot just leave out things you can't explain and call it science or an adequate explanation.

I like this game.

Dave

 

[Dave Rogers]

Thus, you have to analyse the damages development step by step, keep track where the loads/forces are transferred and what failures they may cause, energy applied (force x distance) and absorbed, etc., etc.

And yet, you have made no attempt to carry out this procedure in detail, that you claim is needed to determine the response of the structure. You've made some handwaving arguments based on invalid assumptions and incorrect calculations, and concluded that:

Sorry, I disagree. It was CD.

And when people point out your errors, you pretend they haven't, claim you haven't seen them although you replied to them, complained that they didn't submit them by e-mail, and claim that you don't have to address a correction because all that's required of you is that you clarify your arguments, so you'll only answer direct questions. Implying, of course, that you deny ab initio the possibility of having got anything wrong. So, based on your starting assumption that your work is entirely correct, you reach the conclusion that your work is entirely correct.

You're not just a fraud, you're a transparent fraud.

Dave

 

[Smackety]

It never fails to boil down to, "well, it looks like a CD to me."

 

[GlennB]

Column buckling is often a three hinges plastic deformation phenomenon - kneeling - without fractures. The column ends are often still attached to adjacent structure top and bottom.

Thus, after buckling, the load from above will still pass through the now buckled column and be transmitted to structure below. No free fall will occur.

My bolding.
You went from "is often" to "will" in one graceful dance step. Even though I know zip about column buckling, your fraudulent logic shines through.

 

[Architect]

Simple reason being that they are available in my articles on my popular web site. Copy/paste yourself as you like!

I'm sorry, but no. You were asked to produce structural calculations, now broad generalisations and dubious comparisons.

 

[Architect]

A column can carry a certain load and not buckle! Is that load exceeded, the column buckles! The load it carries then displaces down - the interface changes. That is an initial failure.

And how, pray, does that load displace? Be specific, now.

Column buckling is often a three hinges plastic deformation phenomenon - kneeling - without fractures. The column ends are often still attached to adjacent structure top and bottom.

The last point is wrong. Failure often occurs at the lower and upper joints rather than locally within the column, depending upon the design of the column and the bracing effect of other members at the joints.

Thus, after buckling, the load from above will still pass through the now buckled column and be transmitted to structure below. No free fall will occur.

No, that depends upon the failure mode. See above.

Say that the load is first transmitted to the knee of the column that is now in contact with the floor of the structure below. The force in the column is known. The buckled column + its load (actually the force) may then punch a hole in the floor. That is a second local structural failure (that absorbs energy and starts to arrest further failures). If the floor is strong enough further failures are prevented already then.
If the column buckles outside the building, the column knee will not contact anything at all. The load on the column will drop outside.
Thus, you have to analyse the damages development step by step, keep track where the loads/forces are transferred and what failures they may cause, energy applied (force x distance) and absorbed, etc., etc.

This is just plainly wrong, I'm afraid. But do feel free to post some calculations attempting to prove it.

Re WTC 1 I doubt very much that any columns in the initiation zone buckled at all due to fire/heat (as explained in my articles). And if it had happened the load above would soon be carried through buckled columns via new contact areas on floors (that might have suffered damages) and after that destruction would be arrested.

You seem to place a lot of faith in the ability of a buckled (i.e. failed) column to transmit the full load within the original design parameters.

And the Bazant rubble with density 1025 kg/m3 (mostly air) cannot destroy any columns. But the rubble layer is not there.

Your density argument has been thoroughly debunked many, many times at JREF.

The rubble is not there! It is ejected sideways like a fountain by the energy provided by the CD to destroy the structure below - progressively from top to bottom.

And yet most of the truthers say the building collapsed into its own footprint. Really, we need some consistency here.

The crime of the century was done in front of millions of people - and they were told it was ... just progressive collapse.

Sorry, I disagree. It was CD.

Millions of people and hundreds of thousands of structural engineers, architects, fire engineers........and only you noticed. Arup and wrong. Edinburgh University is wrong. Whoever redrafted the Eurocodes is wrong. Hmmm.

 

[twinstead]

Yes. The crime of the century. Bah! We had all the experts of the world fooled. Even those Chinese guys. Hell, we even had those suckers re-writing building codes over in Europe, those FOOLS! (cue evil chuckle). We would have gotten away with it too, if it wasn't for that Heiwa and his intrepid Truth Movement. Curse you! Curse you ALL!!!!111!!1

 

[e^n]

A column can carry a certain load and not buckle! Is that load exceeded, the column buckles! The load it carries then displaces down - the interface changes. That is an initial failure.

Excellent, we agree so far.

Column buckling is often a three hinges plastic deformation phenomenon - kneeling - without fractures. The column ends are often still attached to adjacent structure top and bottom.

Here we do not. This is not strictly true in the case of the WTC collapses, as we can see column connections breaking as the collapse initiates. However in a simplified limiting case, we should treat them as still connected.

Thus, after buckling, the load from above will still pass through the now buckled column and be transmitted to structure below. No free fall will occur.

Here I am not sure we agree. You say "the load from above", but surely you mean "some of the load from above"? If the column has exceeded its ultimate capacity and subsequently been deformed, its current capacity will be significantly diminished as I understand it, until it becomes essentially a flat plate.

Say that the load is first transmitted to the knee of the column that is now in contact with the floor of the structure below. The force in the column is known.

Is it? Surely the force in the column depends upon its particular configuration as anything greater than its capacity would use up energy in deforming the column further?

The buckled column + its load (actually the force) may then punch a hole in the floor.

Here I totally lose you. If the column is buckled yet still connected to both ends, how can it punch a hole in the floor? We are trying to deal with a best case scenario here where every column absorbs the maximum amount of energy possible. It seems a disconnected column punching through a floor would not satisfy this criteria.

If the column buckles outside the building, the column knee will not contact anything at all. The load on the column will drop outside.

I am equally confused here, how can load "drop outside"? Load is a measure of force, and air is not a particularly resistant structure, and so very little force could be generated on this column? If this column were the only one holding the upper section up, it would begin to descend rapidly? (within a small margin of g).

Thus, you have to analyse the damages development step by step, keep track where the loads/forces are transferred and what failures they may cause, energy applied (force x distance) and absorbed, etc., etc.

I agree that this is the case for a rigorous analysis, but I don't agree that we have enough data to construct such an analysis with any of the WTC towers to the level of confidence we can have in BLBG. NIST have of course done this model for WTC7 and the initiation model for WTC1+2, but I assume you take issue with them for whatever reason.

Re WTC 1 I doubt very much that any columns in the initiation zone buckled at all due to fire/heat (as explained in my articles). And if it had happened the load above would soon be carried through buckled columns via new contact areas on floors (that might have suffered damages) and after that destruction would be arrested.

This does not make sense, you have explained how a failing column must carry less load, and if there is enough force to fail all alternate load paths, the upper section must accelerate downwards. I have not read your work on column buckling, unless you're referring to the calculations you posted here before which ignored the initiation mechanisms in both towers.

However, as I observe in my articles the upper part - the load - seems to self-destruct (CD!) prior to any buckling of columns below.

I see no evidence for this.

So what you see later is not some sort of progressive collapse or crush down by further CD!

And I don't understand this.

The Bazant model - opus I, II & III - cannot be seen on any videos. The upper part and the rubble supposed to drive the crush down are not there!

Of course it cannot be seen on videos, because it is a best case scenario. The situation on the day was far worse for the towers, because an exterior wall section failed, resulting in most of the columns being misaligned.

The rubble is not there! It is ejected sideways like a fountain by the energy provided by the CD to destroy the structure below - progressively from top to bottom.

This is just silly. No CD provides anywhere near enough force to laterally eject the entire mass of the upper section of the towers. You can do the calculations yourself, you know the mass of the upper section, you know the rough mass distribution. Tell me how much it would take.

The crime of the century was done in front of millions of people - and they were told it was ... just progressive collapse.

Sorry, I disagree. It was CD.

Please submit your disagreements to a noted authority.

 

[RevDisturba]

Thanks for everyones reply. I am ceasing posting for the foreseeable future for something that happened in the religion section. This thread doesn't seem as volatile as the religion section and I wish I had of seen it first. Conspiracy theories, at least the 'good ones' rule! Don't forget what happened to Mel Gibson in the movie "Conspiracy theory".

; {>