Merged Applicability of Bazant's model to the real world

[femr2]

How did the trusses push outwards?

I don't imagine they did. The trailing avalanch of mashed-up building however...

Assuming for a moment that you were right, why don't we see the walls bending outwards?

We do. See the perimeter peeling studies at The911Forum.

No, I've seen no reason to bother yet.

Well you can make it up as you go along I suppose. Or you could look at various arguments and proposals from numerous folk including BLGB author(s?) on the topic.

ETA: Have a watch...

 

[Major_Tom]

One very large example of perimeter peeling:

http://www.youtube.com/watch?v=1iT7mmmc-YY&feature=channel_page

It is hard to miss the giant west wall falling away from the building.

If you spent more time observing and less time feeding your own egos, you wouldn't miss such obvious clues.

 

[Major_Tom]

WTC 1 West face at
http://www.sharpprintinginc.com/911..._op=view_page&PAGE_id=97&MMN_position=231:231

the west face is one of the most extreme cases of an interconnected perimeter being pushed out with the motion shown below

and at
http://www.sharpprintinginc.com/911/images/pagemaster/east_wall_peeling.jpg

WTC 2 East face at
http://www.sharpprintinginc.com/911..._op=view_page&PAGE_id=63&MMN_position=148:148

Details of the east face sheet being pushed out as a single, interconnected, unbuckled unit at
http://www.sharpprintinginc.com/911...op=view_page&PAGE_id=121&MMN_position=282:282


WTC 2 West face at
http://www.sharpprintinginc.com/911...op=view_page&PAGE_id=116&MMN_position=281:281

 

[W.D.Clinger]

(In a previous post, I inadvertently reversed Bažant et al's labelling of the sections. In their papers, section C is the upper block and section A the lower. If you substitute C for A and A for C throughout that previous post, it will make more sense.)

With respect to the model's assumption of vertical homogeneity, I see two possible problems with applying that assumption to the WTC towers:

• The mechanical floors might have been different enough to matter.
• Differential collapse rates between the core and the area outside the core, if combined with significant interactions between the two, could conceivably invalidate the assumption of vertical homogeneity.

If I understand you correctly, your objection to vertical homogeneity may be based upon the second of those problems. If so, that's really a problem with the one-dimensionality of the model.

If we dismiss the failure of the outer flooring system, do you think the model can be more reliably applied to what is left?

I'm not sure exactly what you mean by "dismiss"; in any case, you're asking me to speculate outside my competence. With those disclaimers...

As built, the WTC towers satisfied the assumption of vertical homogeneity pretty well, and that continued up through the beginning of the collapse, modulo the weakened state of impacted floors.

If (as femr2 may^* be arguing) the downward progression of floor failures outstripped the downward progression of perimeter and/or core failures, then Bažant et al's assumption of vertical homogeneity would begin to be violated, because sections in which the floors had failed but the perimeter and columns had not would be different from the lower section in which nothing had yet failed. That could make it more difficult or impossible to apply the model(s) to the later portion of the collapse, when the lag was greatest, although it might be possible to work around that problem by treating the frontier of floor failure as the lower crushing front.

I don't think I've seen anyone make that argument, possibly because few people believe that floor failures could have gotten very far ahead of perimeter and core failures.

If floor failure led perimeter and core failure, but not by much, then Bažant et al's assumption of vertical homogeneity remained approximately true and their model(s) should remain approximately applicable (with appropriate parameters).

That said, I'm not an engineer.^†
[size=-2]^* I don't pretend to understand what (if anything) femr2 has been saying, and I no longer try.

^† My areas of competence are not radically different from those of David B Benson, the fourth letter in BLGB.

[/size]

 

[pgimeno]

I don't imagine they did. The trailing avalanch of mashed-up building however...

Yes, but I'm talking about what you presume to be the collapse front all the time. I have little doubt that the peeling happened. Even FEMA describes it.

 

[beachnut]

The general terminal velocity of the WTC 1 SW crush front propogation. Measured by tracing the SW ejecta. Not a single value, a trend.
...

You say 28m/s. Is that the dust? That is too slow for the terminal velocity of people who jumped. People being burned because the fires were not cold, like you truthers say they were too cold to destroy the WTC complex. And like 28m/s is a delusion, your CD is too. Bazant's model, applicable to the real world, your models applicable to fantasy.

Your value is wrong without having to use math, or physics. Like all of 911 truth you talk nonsense and offer weak attacks on NIST, Bazant, and reality.

Do you make this up like Balsamo, talk and divide a number into some other number and pull it out of thin, very thin air? That is right, you still have Ross's failed paper listed as a technical paper on 911. Now that is failure.

You have a disconnect with reality.

 

[femr2]

If (as femr2 may^* be arguing) the downward progression of floor failures outstripped the downward progression of perimeter and/or core failures

Absolutely.

Consider...

...which are overall stills at a similar time to...

Have you spent any time actually studying any of the available footage ?

 

[femr2]

You say 28m/s.

Roughly.

Is that the dust?

No.

That is too slow for the terminal velocity of people who jumped.

A bizarre comment. What on earth has the terminal velocity of an object through air got to do with a linear rate traversal of a crush front ? Absolute nonsense Beachnut.

28m/s is a delusion

No, it's a replicable metric from video evidence.

Bazant's model, applicable to the real world

Very limited in behavioural terms, as this entire thread is discussion of.

your models applicable to fantasy.

What model ?

Your value is wrong without having to use math, or physics.

ROFL.

Have a nice day.

 

[beachnut]

Roughly.

...

What model ?


ROFL.

Have a nice day.

You use your eyes, when you need math and physics.

28 m/s.

Yes much of the WTC, save the dust, insulation, and other light stuff, did at one time go 28 m/s. I now have some more evidence why you can't figure out 911.

You make up your own undefined physics. You are proud and prove it to all.

Dr G's 1D slab model does not, in a similar way that the Bazant et al model(s) do not, model the actual descent mechanism.

You suffer from the same failed view of science as Balsamo and his 11.2g moron math.

You don't understand models, or reality. How does your 28 m/s stuff dovetail with your CD delusiontheory?

Have you published this in a real journal? How long does it take for the WTC tower to collapse? How does the core standing affect the 28 m/s, or is your model of 28 m/s not a model, but a special made up number?

How did you measure this 28 m/s stuff? When a truther goes 1D on the world, it is the sign, the big red flag, of woo. Good for you.

 

[tsig]

I'm not.


You doubt right. Research types of sonic boom ? ROFL.


ROFL. Straight out of the wikipedia article, your first and only port of call. At least re-word that kind of thing when you're trying to sound knowledgeable eh


I've been ROFL'ing almost constantly today, however...

ROFL.

Howabout you read a bit further on in BLGB...

.


Enough (I spared you a little more embarrassment by not highlighting that your waxing lyrical about bullwhips and bullets is also straight out of the wiki entry, oh, oops...)

Have a nice day.

ROFL _rofl ^rofl

 

[femr2]

You use your eyes, when you need math and physics.

Graphing the traversal of the crush front and deriving the velocity data requires a little of all three, but nothing at all difficult.

28 m/s.

Again, roughly, yes.

You make up your own undefined physics.

Nonsense.

How long does it take for the WTC tower to collapse?

Extrapolating the SW crush front traversal to ground resulted in a full traversal time around 14.5s IIRC.

How does the core standing affect the 28 m/s

A nonsense question.

How did you measure this 28 m/s stuff?

Stated several times. Learn to read. Trace the traversal of the WTC1 SW crush front. Graph the derived velocity data.

When a truther goes 1D on the world, it is the sign, the big red flag, of woo. Good for you.

ROFL. What on earth are you rambling about ? Utter nonsense.

Have a nice day.

 

[ozeco41]

...If (as femr2 may^* be arguing) the downward progression of floor failures outstripped the downward progression of perimeter and/or core failures,...

YES and it's not just femr2 who has that bit right. It is something which I thought was known and taken for granted as the mainstream understanding of the 'collapse progression'. What I have called 'global collapse' and described since 2008 as three parallel but staggered in time processes. Office space pancaking, ahead of and leaving the outer columns unbraced to fall later - not much later but definitely later - whilst the core failed mostly by strip down of the horizontal beams as indicated by the 'spires' which remained standing briefly after the main part of collapse was over.

...then Bažant et al's assumption of vertical homogeneity would begin to be violated, because sections in which the floors had failed but the perimeter and columns had not would be different from the lower section in which nothing had yet failed....

YES - which is the central point I have been making - apparently not being understood.

... That could make it more difficult or impossible to apply the model(s) to the later portion of the collapse, when the lag was greatest,...

Not just the later part IMO but yes. That is why the Bazant model does not fit the real world. Recall that I accepted pgimeno's logic differentiating between 'fitting the parameters of WTC collapse to the model' AND 'fitting the model to the real world'.

... although it might be possible to work around that problem by treating the frontier of floor failure as the lower crushing front...

I have suggested other ways of fitting the Bazant model to the realities of WTC but let me not diverge at this stage.

...I don't think I've seen anyone make that argument, possibly because few people believe that floor failures could have gotten very far ahead of perimeter and core failures....

Isn't Internet communication a funny animal. That argument is the main premise underpinning most of my posts on this topic. I would have presumed that most people involved in discussing the topic would either have taken that argument as their starting point OR seen it in the various detailed posts I have made identifying the three separate but linked mechanisms involved in the global collapse.

...If floor failure led perimeter and core failure, but not by much, then Bažant et al's assumption of vertical homogeneity remained approximately true and their model(s) should remain approximately applicable (with appropriate parameters)....

Possibly but I have no interest in either defending or attacking Bazant. Merely in determining "Applicability of Bazant's model to the real world"

 

[ProBonoShill]

Wrong. No surprise you have a CD theory.

What is 28 m/s? The average speed of the entire collapse, the first impact, the last impact?

You can't use 28 m/s as the last floor collapsing. Your speed is the velocity of collapse for the 73rd floor. What is your problem with physics? Do you have problems with math?

Apparently Femr believes the highlighted portions below are equivalent to each other, maybe he's never heard of gravity and momentum:

Whilst I have the doc open...

Originally Posted by BLGB
Since the velocity of the crushing front near the end of North Tower crush-down is, according
to the solution of Eq.(2), z =47.34m/s (106mph), the velocity of escaping air near the end of crush-down is...

...most certainly NOT what they calculate it to be (up to mach 1 !), as the primary North Tower crush front traversed at a fairly constant ~28m/s.

 

[femr2]

Apparently Femr believes the highlighted portions below are equivalent to each other, maybe he's never heard of gravity and momentum:

Whilst I have the doc open...

Since the velocity of the crushing front near the end of North Tower crush-down is, according to the solution of Eq.(2), z =47.34m/s (106mph), the velocity of escaping air near the end of crush-down is...

...most certainly NOT what they calculate it to be (up to mach 1 !), as the primary North Tower crush front traversed at a fairly constant ~28m/s.

You folks really are outdoing yourselves today. A stream of utter nonsense.

The crush front traversal rate used by BLGB is in the damn quote... 47.34m/s.

You may be able to tell that 47.34m/s != 28m/s.



Have a nice day.

 

[ozeco41]

...You're claiming that the upper block, plowing its way thru the lower structure, created a front end that matched perfectly the inside dimensions of the peripheral wall???



And magically sheared all the internal floors perfectly from outer columns ??



And left a massively unstable external wall standing in place???



And it wasn't until the crush front had long since passed by, with the high pressure front IN ADVANCE of it, that the outer walls suddenly threw themselves in all direction??



Or perhaps it was late-firing nanothermite that threw the external columns hundreds of feet …?

THAT's your "ROOSD theory" …?....

I have difficulty telling where your 'funny comments' end and any real content starts tfk.

So I cannot tell if:
A this bit is intended as a 'Poe'; OR
B you are relying on your use of the word 'perfectly' to negate your various claims.

One by one:

• "You're claiming that the upper block, plowing its way thru the lower structure, created a front end that matched perfectly the inside dimensions of the peripheral wall???" During the 'global collapse' the top block in whatever state of disintegration it may have reached fell together with accumulating debris of detached floors. It fell inside the outer tube - fitting near enough despite whatever you mean by 'perfectly'.
• "And magically sheared all the internal floors perfectly from outer columns ??" Not 'magically' - simply overwhelming load. And it probably sheared all the inner connectors as well as the outer ones.
• "And left a massively unstable external wall standing in place???" Yes that is what happened.
• "And it wasn't until the crush front had long since passed by, with the high pressure front IN ADVANCE of it, that the outer walls suddenly threw themselves in all direction??" Er - they fell over??? And not 'long since passed by' - fractions of a second or a few stories other than the corners which naturally were self bracing and survived a bit longer in some cases recorded on video. They fell in various sized blocks and lay themselves down in directions mostly outwards from the original faces of the towers. And few if any of them buckled.
• "Or perhaps it was late-firing nanothermite that threw the external columns hundreds of feet …?" - Your laughing dog belongs here against your suggestion. BTW - a question for 'explosives claiming truthers' - 'How do you get any explosive to throw large structural members hundreds of feet?'

'ROOSD' is Major_Tom's title for the process but - begging a few details in MT's version it is the same old explanation that a few of us have been using for years. Me since late 2007 - early 2008. So if you have to ridicule MT's version (other than his title for it) there are a few of us you need to push out of the way.

 

[femr2]

It is something which I thought was known and taken for granted as the mainstream understanding of the 'collapse progression'.

At last, a voice of reason.

Isn't Internet communication a funny animal.

I don't really think so, but it is certainly a medium through which insight into users mindset can be more than a little surprising.

 

[Major_Tom]

Credit for ROOSD? IT is such a simple idea that many people were talking about it independently of each other. Ozeco, for example.

Credits also to David Benson, Frank Greening, Max Photon, Greg Urich, OneWhiteEye and others using "food based" descriptions (mainly breakfast foods).

Also early FEMA descriptions cited earlier.

But it is the discovery of the whole width of the core that allowed it to be expressed as a list of observations: credit to femr and achimspok.

My ROOSD version was first written about a week after the discovery of the whole width of the core, because that was the final element that allows us to connect the dots.

Many described it, but nobody examined the visual evidence enough to draw firmer conclusions.

There were people on youtube using the description "peeling like a banana" for perimeter movement before I began to do research.

ROOSD was an organic discovery, from many different sources. Maybe that is why the concept appeals to so many people.


I didn't even come up with the catchy name, that was femr. I was calling it OOSRD. Thanks for moving that "R" 3 spaces to the left, femr.

As for me? I just recorded it all.

 

[ozeco41]

At last, a voice of reason...

...I'm glad I stay with my lifelong/career long practice of working out what the hell it is I'm trying to analyse before I engage the maths.

 

[ozeco41]

Credit for ROOSD? ....
As for me? I just recorded it all.

You gave it a name which makes for an easy target to attack.
(oops - I see it was femr2 who improved it to roll off the tongue better)
I happen to like 'ROOSD' and 'OOS' as concise labels.
You have taken the description of the concept a stage or two further than I need.

 

[Major_Tom]

As for credit for the discovery of perimeter peeling....

It is so obvious that nobody can take credit for the original discovery.

But your humble servant, Major_Tom, put the best record together of the collective events to date to further our common knowledge of the collapses.