Merged Applicability of Bazant's model to the real world

[tfk]

Have you tried reading the thread? Or even this page of it? The quote this is taken from is on this page.

944 posts? Nope. I haven't read the whole thread. Not likely to, either.

But gee, you asked for "an engineer to help answer a question".

I asked for the source of the quote so that I could see it in its real context. So that I might be able to give you a better answer. (And, no, the quote on the same page does NOT give sufficient context.)

And this is your reply...?

You guys are like a bunch of drama queens & spoiled brats. Petulant, insulting, dismissive. Demanding that everything be spoon fed to you. Poisoning wells left & right.

So, never mind.

It turns out that I don't need the source of that quote after all.


tom

 

[beachnut]

...
For the purposes of examining Bazant, none of this is particularly relevant anyway, as it is a limiting case energetics based model, which should not be applied to real world behaviours literally.

...

Bazant published his work based on 911 in two days. Why are you failing to publish all this nonsense after 9 years? Publish it.

Looks like you have actually gotten around to reading the ROOSD study.

Publish it. 9 years and you can't beat Bazant? Why? Is that a super engineering acronym, or what?

When will it be published? Never, 911 truth believers only product is talk, no action will be taken because the CD delusion is based on hearsay, lies and fantasy. Can't publish delusions.

You attack Bazant's model by poorly imply there is this study so much more elegant to explain something you guys don't believe happen anyway. Are you debunking the moronic CD theory? It is hard to follow the fake engineering work you allude to at your forum which is solving 911 issues slowly with talk and voodoo engineering.

Start the thread for your study of studies on 911.

Prove your stuff is not moronic nonsense, publish it. 9 years is a long time to take and not expose the evil guys behind 911. Who did the CD? Is Bazant in on it? I mean a paper in two days? How did he do what you guys can't do in 9 years, in two days?

 

[femr2]

Publish it.

As usual Beachnut, you seem awfully confused. The ROOSD study was written by Major_Tom.

Is that a super engineering acronym, or what?

Several months of whining about ROOSD and you never bothered to check what it actually means ? Classic.

ROOSD = Runaway Open Office Space Destruction.

Do you now *get* why I think it's quite funny when you say really silly things like *failed OOS*... Failed Open Office Space. Oh, the irony.

When will it be published?

Is my username Major_Tom yet, or is it still femr2 ?

Never

If you are going to ask a question (to the wrong person I might add), then immediately make up an aswer to it all by your self, then I strongly suggest taking some time out and chilling out. What's that old saying...First sign of madness, talking to yourself. Second sign, answering yourself back. Am sure there are folks getting increasingly worried about you Beachnut.

You attack Bazant's model

No I don't.

by poorly imply there is this study so much more elegant to explain something you guys don't believe happen anyway.

Nope. You're so far off base it's not even funny.

Are you debunking the moronic CD theory?

Do you not understand any of the detail I have posted ? I'd say some of what I've presented certainly shows that theories such as floor-by-floor explosives are patently false, but I wouldn't say it's all encompassing.

It is hard to follow the fake engineering work you allude to at your forum which is solving 911 issues slowly with talk and voodoo engineering.

By all means highlight anything you think is *fake* beachnut. In fact, I insist, though I would request that the mods here at least attempt to keep you in some kind of check. The rabid puppy persona is rather irritating in all of the threads you pollute. Be nice. Be precise.

You want to discuss publishing of the ROOSD study, talk to Major_Tom.

You want to discuss *911 truth*, speak to *911 truth*.

You want to respond to my posts with specific detail you either agree with or disagree with, fine, but be specific and clear as to why.

I'll consider willful failure to do so as stalking./trolling and report further instances without hesitation.

 

[ozeco41]

The idea of one load causing failure is a bit theoretical IMO - with implicit suggestions of uniform distribution and such and all letting go at the same instant...

Let's not let ourselves get caught up in too-linear thinking. Bazant came up with a good way to determine whether the minimum energy neccessary for the task was available. It clearly was. But his model does not always work because there are just too many variables in the real world. In a pure pancake collapse, his theory fits beautifully.

Whoa back there Lefty. My comment that you quote was a throw away in reference to a statement by RM about the force needed to disconnect one floor. Nothing more. It was in no way a comment about Bazant or any of Bazant's models. That said the way you state "...whether the minimum energy neccessary for the task was available." could be misunderstood but I take it as (A) referring to Bazant and Zhou and (B)that we are both aware of the assumption underpinning BZ - the OP of this thread occurred because I Identified that assumption.

The second paragraph of mine likewise is a continuation of that throw away comment on RM's statement about the failure load for one floor.

If there was to be a max load failure it is more likely to be "zip fastener" style with rapid serial failures where one failure results in fall over of shed load landing on the next in line which then fails.......loop back to "results"

...so your comments do not flow from what I said.

I am in broad agreement with the points in your main paragraph even though they are not what my comment was about:

...This may be an even more appropriate description than you had in mind. We have determined that at least two edges of each block C fell inside each block A. This results in a number of "axe blades" hitting the next in-place floor. This is a little more likely to break the floors than is merely slamming a too-heavy weight down on them. I cannot, however, see how it would be possible to cram this large an object into a box without also pressing outward on the walls of the box. The insertion of the lower margins of the C blocks into the A blocks has to have pried the perimeter columns outward at least a little bit, further stressing the seats of the trusses. Simultaneously, the impact of the other margin of the C blocks had to push outward on the perimeter columns as well. So we still have some crush-down going on, even if not in a straight perpendicular direction. Certainly, shoving the columns outward would take less energy than would compressing them axially. Bearing in mind that these columns were each attached over three storeys, they would be most excellant pry bars with which to break the truss seats. So we have two modes of destruction in operation here...

...from here you venture into areas of your own opinions which I may not share.

 

[beachnut]

ROOSD = Runaway Open Office Space Destruction.
...

Everyone knows the super engineering acronym for Major Tom's work. I thought you supported the CD delusion and could help him publish and get this off the internet and where it can be seen in real engineering journals. Why is 911 truth attacking Bazant's work? I thought you were interested in helping your CD group take action. With the veiled weak attacks on Bazant's work, you look like a proponent of the crazy CD delusion.

It is funny how you are upset I answer my own questions. If 911 truth could answer their own questions, you would have figured out 911 over 9 years ago. 911 truth, the group you share delusions with.

What did your post have to do with Bazant's model, save it was a weak attack on Bazant? Have you noticed how many 911 truth (those people with delusions on 911, like CD, and other misunderstandings) people attack Bazant's work due to some paranoid ideas? For instance...
http://911blogger.com/node/9154 (more at bottom)

Why do you attack Bazant's model? I think a few of the 911 truth believers (those with the CD delusion and others) are only exposing their ignorance on models, what do you think?

A serious 911 truther researcher (an oxymoron, save one), skeptic, would put me on ignore when I expose you have nonsense. Posting back, proves you have nonsense on 911, made up junk and BS, with no goal. Need a tutorial on ignore?

Why does 911 truth (if you can't figure out what 911 truth means, then why post in the 911 CT sub forum?) attack Bazant? Ignorance? Lack of engineering skills?

Why do you make veiled attacks on Bazant's model? Same reasons?

... bottom line, no one in 911 truth will publish reality based studies, and those who have published, their work was exposed as delusions and nonsense. You will not help anyone publish, that is fine; the internet for 911 truth is the only place they will publish save the idiotic books by DRG and presentation of woo by Gage, who runs around the world spewing lies and collecting money from paranoid conspiracy theorist; a fringe market.

... why does 911 truth attack Bazant?

http://heiwaco.tripod.com/nist0.htm Heiwa does it, and he has idiotic claims, insane claims.

http://911blogger.com/node/9154 911 blogger does it, but they are a cesspool of idiotic 911 truth claims and delusions.

http://www.bollyn.com/the-gang-of-czech-jews-around-the-collapses-of-9-11 This dolt does it; he is a bigot and makes up more 911 truth lies. Wow.

http://911research.wtc7.net/disinfo/experts/comments/bazantzhou.html Even a favorite 911 truth site does it; is it drugs? Looks like a web site built using lots of meth and paranoia.

http://acebaker.blogspot.com/2008/03/bazant-completely-blows-it.html AceBaker, how do you file this one?

Edited by Lisa Simpson: 

Edited to remove personal remarks.

 

[leftysergeant]

Air pressure is pretty irrelevant imo, as the crush fronts are pretty far ahead of trailing perimeter peel, by which time the overpressure is *long gone*. Turbidity, kinda. A better description imo, is mass funneling between core and perimeter. If that doesn't paint a clear picture, let me know.

Once stuff started to move, the over-pressurization of the air needs to be added to the energy budget. It gets distributed very widely. It was more than noticeable inside WTC 7 and in the stairways in the north tower as a wind that blew people back up strairways.

I would suggest the simplest route is ANOTHER smaller footprint ROOSD-like process down the middle of the core, which as it faces much more structural resistance is not only slower, but does arrest. Due to mass distribution resulting from initial tilt, more mass was present south-side (wtc1) so north side core arrested earlier. Without a functional mass funneling container, the driving mass *slipped off* the lower core, leaving the observed remants.

We have visual evidence against it. The flow of smoke up through the center of the dust plume shows that air was flowing unperturbed up the elevator shafts. Sequential failures of floors within the core would have caused a pulse and would probably have blown open the stairwell through which the few survivors of the north tower collapse were escaping.

When the spire became visible in the north tower, the dust was just sitting there. Your mini OOS would have drawn it downward with the rest of the dust.

The cross members are still visible in place when the spire is revealed briefly. At the same time, the columns can be seen to be separating and oscillating.

Looks like mechanical resonnance to me.

 

[twinstead]

So, what about this column-welded rebar?

Anyone? Enquiring minds want to know!

Shhhhh. The grownups are talking

 

[leftysergeant]

...from here you venture into areas of your own opinions which I may not share.

Do you agree that the effect of leverage on the tops of the perimeter columns was considerable and may have changed the amount of weight in rubble that had to be applied to the floor as weight, static or dynamic, to cause failure?

 

[ergo]

The floor/wall connection at the perimeter entailed features which provided the ability to resist both vertical and horizontal loads.

The vertical connection was comprised of the truss seat welded to the column and shear studs welded to the columns and embedded in the vertical edge of the concrete. These connections provided for resistance of the vertical loads.

The horizontal connection was comprised of the truss to truss seat bolts, the strap anchors, and the welded gusset plate. These connections provided for resistance of horizontal loads.

Although I haven't seen anything about it, it would make sense that the 1/2" diameter rebar at the perimeter of the concrete was welded to the shear studs from the columns. Perhaps Newtons Bit can clarify what he meant.

Thanks, Tony. So what's your take on what NIST says about the truss connections for collapse initiation? The FAQ (linked to on previous page) says the "vast majority" remained intact for the 'pulling in' work, but you have given a different picture based on what you see would be realistic to achieve that sagging. Has NIST contradicted itself somewhere else with regard to the "vast majority" statement, or are they simply relying on the heating factor?.

 

[ergo]

Shhhhh. The grownups are talking

 

[femr2]

Once stuff started to move, the over-pressurization of the air needs to be added to the energy budget.

It's trivial.

Sequential failures of floors within the core would have caused a pulse

Where (and those of the OOS regions wouldn't ? )

When the spire became visible in the north tower, the dust was just sitting there. Your mini OOS would have drawn it downward with the rest of the dust.

This makes no sense at all.

The cross members are still visible in place when the spire is revealed briefly.

The spire is a very poor word, through I'm aware of its common usage. The core remnant was just that, a section of the core. Destruction of that portion arrested. remaining cross-members is to be expected.

At the same time, the columns can be seen to be separating and oscillating.

Looks like mechanical resonnance to me.

You appear to be suggesting that the primary mechanism of core destruction was resonance.

That would be leaping through daffodils into the Woody vale of directed energy weapons, and interferometry.

Not a good idea at all.

You'd also have to ask yourself where the core floor assemblies went if not down through the core sequentially.

Primary mechanism of core destruction was it getting mashed by descending mass. Would you agree, or not ?

If you are applying your interpretation only to post-primary-descent core remnant destruction, then I suggest a more probable scenario is lateral displacement at the base due to enourmous KE transfer as debris impacted ground and basement levels, kicking out core support from the base, as evidenced by vertical descent of the remnant after a period of rhombus-like lateral movement.

 

[femr2]

Everyone knows the super engineering acronym for Major Tom's work.

Excellent. ROOSD for those as don't

I thought you were interested in helping your CD group take action.

Well that's one of your trademarked delusions Beachnut. I'm just me.

It is funny how you are upset I answer my own questions.

Not at all, just showing concern for your well being mate

What did your post have to do with Bazant's model

Not a lot. It was a response to a post.

Why do you attack Bazant's model?

Yet again, I don't. Clarify it's applicability to the real world (the thread title), sure.

Rest of your post is soap-box trolling. Reported.

Have a nice day.

 

[leftysergeant]

It's trivial.

The way that dust erupts from opening in the collapsing front tells me that there was a great deal more than one atmosphere inside the structure. The whole thing was designed to move a bit in the wind., but only in a wind from one direction at a time. We now have a wind blowing in every direction at once inside the structure. Has to have some effect.

Where (and those of the OOS regions wouldn't ? )

Air would not smoothly carry smoke upward with even broken flat objects moving down the air column. There would be perturbations and interruptions of some sort.

This makes no sense at all.

Did you miss the fact that the dust plumes, over their entire length. are drawn downward with the collapsing structure. And look at the segments of perimeter columns falling outside the footprint. The dust becommes entrained behind them.

The spire is a very poor word, through I'm aware of its common usage. The core remnant was just that, a section of the core. Destruction of that portion arrested. remaining cross-members is to be expected.

Seeing how nicely it dealt with the upper core, I suspect that it arrested early.

You appear to be suggesting that the primary mechanism of core destruction was resonance.

That would be leaping through daffodils into the Woody vale of directed energy weapons, and interferometry.

Mechanical resonnance is a known phenomenon. See "Galloping Gertie" on Google Search.

You'd also have to ask yourself where the core floor assemblies went if not down through the core sequentially.

They were far less massive, unitary structures as the office fllors. Some can be seen to fall away in pieces as core columns separate, trailing dust (which whacky old Steven thinks is thermite smoke.)

Primary mechanism of core destruction was it betting mashed by descending mass. Would you agree, or not ?

At the top where block C impacted, there would be some limited crushing. This would arrest as the cores become larger further down.

They were impacted by huge moving objects, but from the side. This would set uip the resonnace. Probably more energetic resonnance than the wind caused in Gallpoing Gertie.

If you are applying your interpretation only to post-primary-descent core remnant destruction, then I suggest a more probable scenario is lateral displacement at the base due to enourmous KE transfer as debris impacted ground and basement levels, kicking out core support from the base, as evidenced by vertical descent of the remnant after a period of rhombus-like lateral movement.

That could have, but did not occur anywhere along the length of the columns during collapse once block B gained sufficient mass. As assymetrical as the collapse was. I am sure that a lot of lateral force was being applied at all times. The last columns appear to be still standing and oscillating when most of the rubble was already on the ground.

 

[femr2]

The way that dust erupts from opening in the collapsing front tells me that there was a great deal more than one atmosphere inside the structure.

Sure. Enourmous overpressure between OOS floor slabs, especially approaching each other at 28m/s. But relative to the other forces at work, pretty trivial. Some propogating back up through the debris, stirring the pot a bit, sure, why not.

The whole thing was designed to move a bit in the wind., but only in a wind from one direction at a time. We now have a wind blowing in every direction at once inside the structure. Has to have some effect.

So what exactly are you suggesting the effect was ?

Air would not smoothly carry smoke upward with even broken flat objects moving down the air column. There would be perturbations and interruptions of some sort.

By the time the core remnant became visible, thr core floor assemblies were heading for or impacting the ground Lefty.

Did you miss the fact that the dust plumes, over their entire length. are drawn downward with the collapsing structure.

Nope. I've looked each available video in probably ridiculous detail.

And look at the segments of perimeter columns falling outside the footprint. The dust becommes entrained behind them.

And ?

Mechanical resonnance is a known phenomenon.

Of course, but I see absolutely no significant core destruction being caused by resonance.

Here's a collection of core videos...

http://www.youtube.com/view_play_list?p=DE95AAC394319BA5

...please feel free to specify one which supports your theory.

Some can be seen to fall away in pieces as core columns separate, trailing dust.

Again, please feel free to specify video in which such can be seen.

At the top where block C impacted, there would be some limited crushing. This would arrest as the cores become larger further down.

Yes, leaving the core remnants as witnessed.

They were impacted by huge moving objects, but from the side.

Am sure they were getting a bit of hassle from all sides.

I am sure that a lot of lateral force was being applied at all times.

Am sure you are correct, though surface area is going to favour vertical forces.

The last columns appear to be still standing and oscillating when most of the rubble was already on the ground.

Nevertheless, the core remannt (wtc1) did not *fall apart*. It moved laterally to the west, then descended vertically, as evidenced in the collection of videos I provided you with above. (I would not expect such huge sections of column to be stationary, slenderness ratio an-all-that)

Could a few of the tallest remnant columns (a small fraction of the remnant) have broken because they wobbled enough to break the splices, sure, but that doesn't apply to the core remnant as a whole.

 

[ozeco41]

Do you agree that the effect of leverage on the tops of the perimeter columns was considerable and may have changed the amount of weight in rubble that had to be applied to the floor as weight, static or dynamic, to cause failure?

Yes - it is certainly a factor. I have no way of accurately quantifying the relative contributions from downwards static weight, downwards falling weight and horizontal "leverage".

 

[GlennB]

Could a few of the tallest remnant columns (a small fraction of the remnant) have broken because they wobbled enough to break the splices, sure, but that doesn't apply to the core remnant as a whole.

While I agree with the gist of the rest of your post, it seems to me that the impact and settling of 000's of tons of debris at the base of the remaining core would have a serious effect on that alread rather fragile structure. Also that it could take a significant time for that effect to propagate upwards.

er, but that ain't really proper engineering talk

 

[femr2]

While I agree with the gist of the rest of your post, it seems to me that the impact and settling of 000's of tons of debris at the base of the remaining core would have a serious effect on that alread rather fragile structure. Also that it could take a significant time for that effect to propagate upwards.

I tend to agree. The initial lateral movement of the core remnant, followed by vertical drop suggests a rhombus type movement. It might be useful to apply the tracing techniques to core remnant movement, so that a position time graph can be presented. Hmm.

er, but that ain't really proper engineering talk

Am deliberately using words like *wobbled* in this context. I don't think it's wise to suggest that resonance destroyed the core.

Can you imagine the field day some folk would have if I suggested it ?

 

[leftysergeant]

So what exactly are you suggesting the effect was ?

It increased the pressure outward on the perimeter columns, thus further stressing the floor connections.

By the time the core remnant became visible, thr core floor assemblies were heading for or impacting the ground Lefty.

But it takes time to build up enough mass to break a small floor, especially as compared to a large one with little excess rigidity. The greater the free span, the more fragile a structure is. The delay in accumlating enough wieght and the sudden increase in the amount of solid matter travelling down the core would have caused some pulse in the flow of smoke upward.

Here's a collection of core videos...

http://www.youtube.com/view_play_list?p=DE95AAC394319BA5

...please feel free to specify one which supports your theory.


Again, please feel free to specify video in which such can be seen.

This is going to take a while.

 

[Tony Szamboti]

Thanks, Tony. So what's your take on what NIST says about the truss connections for collapse initiation? The FAQ (linked to on previous page) says the "vast majority" remained intact for the 'pulling in' work, but you have given a different picture based on what you see would be realistic to achieve that sagging. Has NIST contradicted itself somewhere else with regard to the "vast majority" statement, or are they simply relying on the heating factor?.

The problem is that NIST needs to apply an extreme overload to the trusses to get them to sag anywhere near what they say they did. The only way they can do it is to show the analysis for the trusses next to a number of allegedly disconnected trusses.

The trusses which weren't near anything disconnected, and only handled their standard load, could not possibly have sagged very much regardless if there was some local buckling when it expanded at first.

NIST is being deceptive by not showing the stresses and deflections in all of the trusses on the 98th floor, where the collapse initiated, and just showing what they imply is typical. It could have only been one that was handling the load from a number of disconnected adjacent trusses, but that isn't typical if they say the vast majority remained connected.

Take a hard look through NIST NCSTAR 1-6D, bearing in mind what I am saying.

I don't believe the south wall of WTC 1 failed due to truss sagging and that the failure then magically propagated across the building. NIST just does a hand wave for the propagation, as they don't have anywhere near enough of an overload to cause failure in the east and west perimeter columns. I think the core was dropped and that is what caused the inward bowing due to the core pulling on the perimeter columns through the floors. That is why it is important to understand that the connections were strong enough to pull them inward, but it wouldn't have been due to truss sagging.

 

[femr2]

The problem is...

One problem is that you are making assertions, and then repeatedly ignoring responses. So, again...

Tony,

From prior discussion it is clear that your WTC 7 *jolt* statement relates to the data blip at the 10s mark in this graph generated by David Chandler...

I have repeatedly shown you the following WTC 7 velocity trace...

...highlighting the following:

a) An eight storey drop equates to 12.75*8=102ft.
b) 102ft drop of the NW corner equates to ~14.8s on my provided graph.
c) There is a slight behavioural change at that point in time, but no significant *jolt*.
d) Change in the trend of velocity does not occur until around the 16s mark.
e) At 16s the NW corner has descended ~200ft.

After the NW corner has descended 102 ft the bottom of the *upper block* is already through your *rubble layer*.

102 ft of *removed building*, 102 ft of descent.

The trend of the velocity does not change until the NW corner has descended another 100 ft.

That's another 8 storeys.

Tony, please... make your position clear.

At what point in time (specifying upon which graph) are you stating that the "deceleration of 14 mph" occurred, and what are you stating caused it ?