Merged Applicability of Bazant's model to the real world

[ozeco41]

Among all the noise this little bit of support for the OP from tfk:

....Bazant is right.

1. He is right about his model.
"Right" in this context means that he defined it explicitly.
It's a model. It has strengths & weaknesses. He discusses both of those in detail.
He is right about his math.
He is right about his conclusions.

He does not make the mistake (as bozos do) of confusing his model for reality.

That's my conclusion about Bazant....

...which, if the thread ever returns to the OP, is what that OP was about.

tfk says Bazant is right and that he doesn't confuse his model for reality. That was the premise of the OP. There are bits of reality where Bazant's model does not apply. Some of us were not sure where Bazant's model does not apply to reality. Conversely some of us claimed or at least acted as if Bazant applied to all situations.

I was one of those who were unsure as to where the line of applicability was when the thread started. I'm a bit clearer now - clear enough for my purposes at least. I would not go so far as to describe as 'bozos' those who thought Bazant applied to all bits of reality - even though I wasn't one of them. Let's hope that the situation is now clearer for everyone.

 

[newton3376]

I was surprised to see me being quoted as saying something I never said. I even had to think about "ISTR" for a bit, having never used that.

This is not newton3376's fault by any means; it's just ergo, mindlessly replacing Dave Rogers with Dave Thomas.

LOL...I had to think about "ISTR" for a few seconds also before I got it.....

At least ergo is reliable in making mistakes....

 

[tfk]

I was one of those who were unsure as to where the line of applicability was when the thread started. I'm a bit clearer now - clear enough for my purposes at least. I would not go so far as to describe as 'bozos' those who thought Bazant applied to all bits of reality - even though I wasn't one of them. Let's hope that the situation is now clearer for everyone.

First, a couple of "set the stage" observations:

We are talking about a field (structural engineering) that is as "objective" as they come. "Objective" in engineering means "one right answer, all others are wrong".

We are talking about a specific application (modeling) within that field that is somewhat subjective. There is an art to building models, whichrequires experience & judgment in deciding what are the large effects (which must be considered) and which are the small ones (which can be safely ignored).

So even the artistic side of this issue demands direct, pertinent experience (structural engineering) within the direct, pertinent field (collapse of very large structures).

We are not talking about a subjective field, where everyone's opinion is just as valid as everyone else's. We are not talking about the cutting edge of knowledge, where revolutionary breakthroughs occasionally turn the entire field on its head.

As a result of the above, for every bozo who turns turns out to be an Einstein, there are 10,000 bozos who turn out to be bozos.

I would highly recommend that you play the house odds on this one.

Now, with the background set ...

I would never describe anyone who was looking for the truth about anything as "a bozo". The one & only allegiance that I have in all of this is to the truth. As best we can determine it.

I would never describe as "a bozo" anyone (even engineers) who did not understand the details or the general jist of something like Bazant's papers. They were written (IMO) for engineers, not for the general public, and take a bit of knowledge & effort to work thru.

I would never describe as "a bozo" anyone who questioned or doubted his conclusions.

But there is a right way, and a wrong way, to proceed once one has questions & doubts.

The first step is to keep one's own ego in check. That requires an honest (occasionally painful) assessment of one's own depth of understanding in the specific field.

In the case of structural engineering, there is a reason that they don't hand out BS degrees after ten weeks of intense study. There is a reason that it takes about 8 years to get a PhD.

And there is a reason that smart firms do not hand responsibility of large projects to newly minted BS's, MS's or PhD's.

Industry has a technical term for a wet-behind-the-ears BS, MS or PhD, with too much education and little practical experience: "impending disaster".

Generally, it takes at least a decade (or two) of direct working experience in any engineering field to become truly adept. Not intended to piss off any of the young ones in any field. But the "more experienced" practitioners of all fields (i.e., old farts) will back me up on this.

As does my own personal experience. This country's engineering industry desperately needs an apprenticeship program, where the newly minted engineers belong, body & soul, to an older one. Who sees that he learns the ropes before being given too much responsibility, too soon, and thereby seriously hurting someone or some thing.

So, wrapping up this diatribe, anyone can ask questions.
If getting the right answer is important, then:

A smart person will honestly & objectively assess his own level of expertise in the field of the question.
A smart person will ask questions of seasoned experts. Not amateurs
A smart person will ask questions of multiple experts to see if the experts' answers agree or disagree. If the experts disagree, then it suggests that the question is not well understood. Even by the experts. If the experts agree, then it suggests the opposite.
A smart person will listen carefully to the answers that the experts supply. And give them appropriate weight. Even over their own doubts.

There is absolutely no difference between the right way to find correct answers in this case and in any "mature" field (e.g., nuclear physics, quantum physics, brain surgery, etc.) in which one hasn't sufficient background to determine something for themselves.

One can:

A) behave like a typical young&stupid teenager & decide that all the adults, excuse me, "experts" in the world are stupid, incompetent and/or participants in a giant, evil conspiracy ...

or

B) one can address the issue like a thinking adult.

If someone has been presented with all the above, shown that they don't understand the necessary concepts, and yet stubbornly continues to insist that, despite absolutely zero education or experience in an objective field, their "feelings" trump the consensus of* the world's engineering community ...

... THEN that person graduates - in my estimation - from some combination of Young&Stupid, arrogant and/or paranoid to "bozo".


tom

* Note the invocation of "consensus of experts". Not "every expert".

Every field has a certain number of unbridled egotists, iconoclasts, incompetents & (sadly) mentally ill.

PS. It is revealing, IMO, that none of the truthers posting here (except Tony Sz) will simply & honestly divulge their academic & professional backgrounds.

Even enik, who claims to be a PE with >20 years experience, will only say that he "worked in" certain industries (nuclear to automotive), but refuses to disclose his job title or responsibilities.

In my experience, here & elsewhere on this topic, every debunker has openly disclosed their backgrounds, when asked. And very, very few of the truthers have.

You don't think that this is merely some curious coincidence, do you?

 

[enik]

Even enik, who claims to be a PE with >20 years experience, will only say that he "worked in" certain industries (nuclear to automotive), but refuses to disclose his job title or responsibilities.

Nice speech tfk, even though it doesn't pertain to the thread topic. I have put in to get my PE here in Texas. Found 3 other PE's to put in a good word for me. I even passed the "ethics" test that is required before submitting an application. That will make 2 PE's for me.

My job title is Senior Project Engineer. I design, assemble, and test structural liner hangers to depths of 10,000 feet which must sustain pressures to 8,000 psi, temperatures to 300F+, and loads of 0.5-1 million pounds. They also must resist torque due to directional drilling at these depths. Drilling for oil is not a straight down process anymore. We now drill horizontal for miles. I use FEA in my designs and along with the necessary hand calculations, get the required funding approved for procuring the hanger bodies, casings, seals, etc. from 5" diameter up to 16" for testing. These tests can cost upwards to $50,000, but if my design fails at 10,000 feet, it could be up to $1 million of lost revenue a day in retrieving it.

I started out in the USN in the 80's, mechanic in the engineroom on the USS Enterprise. Graduated with a BS in ME in 3 1/2 years, worked in nuclear construction at San Onofre (seismic upgrades from the earthquakes) and I designed front end modules for several Ford vehicles while getting my MS in ME. Is that good enough for you?

 

[tfk]

Nice speech tfk,

I thought it was OK.

even though it doesn't pertain to the thread topic.

It pertains directly & explicitly to the issue that oz raised about my use of the word "bozo".

I even passed the "ethics" test that is required before submitting an application. That will make 2 PE's for me.

I noticed nothing in your experience about forensic examination of collapsed skyscrapers.
I noticed nothing about the design of anything close to the complexity of an intact building, much less one 100x more complex: one that has had a jetliner fly into it.

Did the ethics portion of your PE exam mention "keeping your public pronouncements within the purview of you field of actual expertise?"

My job title is Senior Project Engineer. I design, assemble, and test structural liner hangers to depths of 10,000 feet which must sustain pressures to 8,000 psi, temperatures to 300F+, and loads of 0.5-1 million pounds. They also must resist torque due to directional drilling at these depths. Drilling for oil is not a straight down process anymore. We now drill horizontal for miles. I use FEA in my designs and along with the necessary hand calculations, get the required funding approved for procuring the hanger bodies, casings, seals, etc. from 5" diameter up to 16" for testing. These tests can cost upwards to $50,000, but if my design fails at 10,000 feet, it could be up to $1 million of lost revenue a day in retrieving it.

Senior Project Engineer. Same here.

"… structural liner hangers …" I'm envisioning large hooks on the end of long cables.

Are these hooks pressure vessels? or solid hunks of steel?
If solid hunks of steel, who are you trying to impress with 8000 psi?

You "design…". OK
You "assemble & test". That seems odd.

I assemble first prototype parts only. Then tech take over with later prototypes.
Once we're ready for prime time, it gets turned over to manufacturing.
I write assembly procedures & test procedures.
I wander out to production periodically to watch the folks on the line assemble my designs. The Manufacturing Engineer & I work closely to make sure the assembly process goes as the design intends.

A project engineer assembling parts. Seems like a prescription for disaster. On many levels.

If I need to test assemblies, it is considered good practice (understated version of "absolutely critical") that the parts be assembled, NOT by engineers, but by the line assemblers.

I started out in the USN in the 80's, mechanic in the engineroom on the USS Enterprise. Graduated with a BS in ME in 3 1/2 years, worked in nuclear construction at San Onofre (seismic upgrades from the earthquakes) and I designed front end modules for several Ford vehicles while getting my MS in ME. Is that good enough for you?

Sure, that's good enough.

Why did it take 5 posts to get a response?

I'll now accept that you are a mechanical engineer who runs from board to board, bragging that you've produced an unpublished, unreviewed FEA as tho that carried any professional weight.

This is a "forest vs. trees" issue, enik.

You are standing there, waving around your misshapen twig for the clueless.

And ignoring the forest of experienced engineers who, working within their fields, have leveraged 100,000x more experience, 10,000x more time & resources, and produced models 10,000x more detailed … & come to reasoned conclusions that are consistent with the evidence.

I am absolutely, 100% certain that the clueless think that you're an engineering God.

For me, an FEA by a guy who designs big underwater hooks might impress me if we were talking about, well, big underwater hooks.

The collapse mechanisms for skyscrapers? Not so much.

tom

PS. I saw your comments about "doubting my honesty" re: catheter design. I see your mama never taught you not to slander people behind their backs.

Pretty cowardly, IMO.

PPS. You don't know Jack about catheter design.

 

[enik]

"… structural liner hangers …" I'm envisioning large hooks on the end of long cables.

Using your own quote, “You don't know Jack [about liner hangers].” Do some research.

I assemble first prototype parts only.

I can do it all, design, analysis, drafting, releasing, procurement, rigging, testing, probably more than a typical engineer. We have hourly folks that help out in the test cells, after all we are talking about assemblies weighing 1,500 lbs to 3,000 lbs. Incidentally, I can also install and wire strain gages and analyze the results to ensure my FEA’s are correct.

If I need to test assemblies, it is considered good practice (understated version of "absolutely critical") that the parts be assembled, NOT by engineers, but by the line assemblers.

Do you still use your slide rule?

I'll now accept that you are a mechanical engineer who runs from board to board, bragging that you've produced an unpublished, unreviewed FEA as tho that carried any professional weight.

I now accept that you are unqualified to review said work.

PS. I saw your comments about "doubting my honesty" re: catheter design. I see your mama never taught you not to slander people behind their backs.

How about showing us your FEA. I’ll retract if I slandered.

 

[rwguinn]

...

Did the ethics portion of your PE exam mention "keeping your public pronouncements within the purview of you field of actual expertise?"



...
tom

Texas Engineering Ethics Exam:
Section 1: Direct Supervision and Sealing of Engineering Work
Section 2:“Why Licensure?”
Section 3: Competitive Bidding, Political Contributions, and Marketing
Section 4ractice in Accordance with Accepted Engineering Practices and Standards
Section 5: Conflict of Interest
Section 6: Practicing Without a License
Section 7: Moral Courage

All questions require simply an answer of which section of the code deals with a particular scenario. And you get to take it on-line, so it's basically open book.

You do have to pass the PE exam (as well as the EIT, or, as it's known now, the "Fundamentals of Engineering" exam (unless you passed the PE already and get a waiver from the Board).
Essentially, all PE stuff is really geared toward the "Cookbook" guys (As a primarily R&D type, as well as a PE, I can sneer at them all I want)
So if you design to Code, and follow the rules of the State with regard to your activities before affixing your stamp to a document, the TBPE won't bother you. You can still be sued, however...

 

[carlitos]

As of my writing, this thread is the only google result for "structural liner hangers" The singular receives no results. What are they?

 

[rwguinn]

As of my writing, this thread is the only google result for "structural liner hangers" The singular receives no results. What are they?

As an edumacated guess, Casings (hole liners) are dropped into wells as they are drilled, to isolate various porous layers (water tables and such) from contamination by or into the well itself. They are suspended from hangers. That would make them tension doo-lollies, and not subject to buckling...
Just a guess, though, on my part.

 

[tsig]

As an edumacated guess, Casings (hole liners) are dropped into wells as they are drilled, to isolate various porous layers (water tables and such) from contamination by or into the well itself. They are suspended from hangers. That would make them tension doo-lollies, and not subject to buckling...
Just a guess, though, on my part.

Looks like you were right:

Nu Flow’s patented, cured-in-place pipe (CIPP) system creates a permanent, structural pipe inside the existing host pipe system, without digging or destruction to buildings or landscape. Our CIPP is a seamless, jointless, pipe-within-a-pipe that is used to rehabilitate deteriorating sanitary drain and storm sewer lines, including mechanical systems, with minimal disruption.



A hanger for these would be frame hung from a big hook.

 

[Newtons Bit]

As an edumacated guess, Casings (hole liners) are dropped into wells as they are drilled, to isolate various porous layers (water tables and such) from contamination by or into the well itself. They are suspended from hangers. That would make them tension doo-lollies, and not subject to buckling...
Just a guess, though, on my part.

In a structures sense they also prevent cave-ins of non-cohesive materials (i.e. sand) as the shaft is being drilled as well. They're not columns, in the sense that they are supporting weight from above, as the walls will deform inwards and apply pressure on all sides. Friction keeps them from sliding down. Pipes that are non-compact (which is defined by the ratio of diameter/thickness) will have problems with local buckling before the entire shape yields. They would have to resist the force of the material around them pushing in as well as the force of whatever fluid inside of it pushing out. I imagine wells at extreme depths have a problem with too much pressure in the line.

One does not need FEA to design such things. An AISC Manual of Steel Construction and a working knowledge of hoop stress will work fairly well. A book on plates and shells by someone such as Rourke or the mad Irishman: Timoshenko will suffice for the non-compact sections. FEA will make it quicker of course.

 

[tfk]

Using your own quote, “You don't know Jack [about liner hangers].”

Never said I did. That's why I offered "I'm envisioning …"

Why don't you get the chip off your shoulder & tell us what liner hangers are.

I'll be curious to hear how far from "hooks on long cables" they really are.

I can do it all ...

Except keep your ego in check.
Except admit to yourself that you don't know Jack about skyscraper construction or destruction.
Except leverage the common sense that God gave a fence post to realize that you're an alleged professional engineer defending the ludicrous & indefensible.

I'll now accept that you are a mechanical engineer who runs from board to board, bragging that you've produced an unpublished, unreviewed FEA as tho that carried any professional weight.

I now accept that you are unqualified to review said work.

LMAO.

Nice dodge.

Care to explain exactly what weight you think that your completely undefined, nebulous "analysis", published on some obscure truther website, carries within our profession?
Oh, that's right. None.

To which professional journal have you submitted it?
Oh, that's right. None.

Have you brought it to the senior engineering staff in your own company?
If you still have a job, I'd guess that the answer to that question is "no".

Speaking of "unqualified", you're the very definition of "unqualified": a Truther Engineer…!!

How many other engineers in your company know that you're a truther?

Do you brag about that professional humiliation?
Or do you live in the closet?

How about showing us your FEA. I’ll retract if I slandered.

Edited by jhunter1163: 

Edited for civility.

What on earth makes you think that I'd disclose my ex-company's proprietary information just to satisfy a couple of truther idjits?

I say again: You're a truther engineer. What on earth makes you think that I give a rat's ass about your slander or your approval?

The day that incompetents, like Truther Engineers, do NOT find me obnoxious & abrasive for pointing my finger & laughing at their incompetence, is the day that I figure I'm losing my game.

Every field has its occasional incompetents.
Medicine has doctors who hawk laetrile & aroma therapy.
Physics has its perpetual motion & free energy clowns.
Aviation has Balsamo & Lear.

Architecture has Gage.
And engineering has you and a couple other bozos.

Engineering & the rest of those professions have survived incompetent, embarrassing clowns in the past.
They will all survive today's truthers, with nothing more than a couple of jokes, rolled eyes & shrugs.


tom

 

[Rat]

Please try to address the argument, rather than the arguer. Be civil and polite. This goes for everyone.

Replying to this modbox in thread will be off topic  Posted By: Rat

 

[femr2]

...if the thread ever returns to the OP...

You never know eh.

There are bits of reality where Bazant's model does not apply. Some of us were not sure where Bazant's model does not apply to reality. Conversely some of us claimed or at least acted as if Bazant applied to all situations.

I was one of those who were unsure as to where the line of applicability was when the thread started. I'm a bit clearer now - clear enough for my purposes at least. I would not go so far as to describe as 'bozos' those who thought Bazant applied to all bits of reality - even though I wasn't one of them. Let's hope that the situation is now clearer for everyone.

I'm sure that instances of misapplication will wend their way here.

No-one roun'ere has any excuse to cite any of the Bazant et al papers without giving some thought to the scope.

Bazant proves there was enough energy available, even in a limiting case, for propogation to ground, given the defined post-initiation state.

That's about it.

 

[Carll68]

Hi. My name is Jimmy Truth from the UK. I have a specific problem with John In Pittsburgh, PA, USA who is an audiologist, and my problem is regarding a peer reviewed audiology study he performed years ago. I want to do what is best, so I think I will take this argument up with Cindy in London, England, who is a Realtor. I believe it is in the best interest of getting to the heart of the matter that this discusion take place over the internet also. Mind you, John is available to hear my argument and adress it personally - and via the proper channels - but, nah...I think the best way to make change and find the truth of the matter is to continue to berate Cindy with this argument. I will then claim victory over John, despite never presenting it to him and Cindy showing me many errors in my work, and then proceed to state emphatically that I have proven John wrong, 'whilst using cool lil' UK slang.

By the way, I work as a landscaper. Tis' what I do, eh?

Think about it.

 

[twinstead]

Hi. My name is Jimmy Truth from the UK. I have a specific problem with John In Pittsburgh, PA, USA who is an audiologist, and my problem is regarding a peer reviewed audiology study he performed years ago. I want to do what is best, so I think I will take this argument up with Cindy in London, England, who is a Realtor. I believe it is in the best interest of getting to the heart of the matter that this discusion take place over the internet also. Mind you, John is available to hear my argument and adress it personally - and via the proper channels - but, nah...I think the best way to make change and find the truth of the matter is to continue to berate Cindy with this argument. I will then claim victory over John, despite never presenting it to him and Cindy showing me many errors in my work, and then proceed to state emphatically that I have proven John wrong, 'whilst using cool lil' UK slang.

LOL spot on

 

[rwguinn]

Where did they all goe?

 

[Major_Tom]

I wrote this May 17th of last year, a few days after I started posting, and have repeated it many times before and since then:

A word of advice for all posters:

The papers Bazant & Zhao and Bazant & Verdure present different arguments with different purposes.

BZ describes a best case scenario for survival.

BV derives actual equations of motion which are intended to be applicable actual buildings, the most famous case being WTC1.

If you keep mixing the concept "best case scenario for survival" with the actual equations of motion derived in BV intended to describe the movement of actual buildings, you will argue yourselves into a corner.

Here are some basic questions I asked repeatedly since May:


1) In BL, can you explain why Dr Bazant insists that crush down must be complete before crush up occurs. Does he mean this literally?

2) Do you consider the equations of motion in BL, equations 12 and 17, to be accurate considering the information in the ROOSD study?

3) Is the following statement true or false:

Dr Bazant believes that a crush-down phase must continue to completion before a crush up phase can begin.

If you answer false, please provide evidence to the contrary.

4) Is ROOSD consistent the claims of crush down preceding crush up in BV and BL?



5) Consider from BL:

"So it must be concluded that the simplifying hypothesis of
one-way crushing (i.e., of absence of simultaneous crush-up),
made in the original paper, was perfectly justified and caused
only an imperceptible difference in the results. The crush-up
simultaneous with the crush down is found to have advanced
into the overlying story by only 37 mm for the North Tower
and 26 mm for the South Tower. This means that the initial
crush-up phase terminates when the axial displacement of
columns is only about 10 times larger than their maximum
elastic deformation. Hence, simplifying the analysis by neglecting
the initial two-way crushing phase was correct and
accurate."

What does he mean by these claims? Do you really believe this claim?


6) Or how about this from BL:

"Blocks C and A can, of course, deform. Yet, contrary to
the discusser’s claim, they may be treated in calculations as
rigid because their elastic deformations are about 1,000 times
smaller than the deformations at the crushing front."

This is how Dr Bazant justifies the survival of the upper block until reaching earth in BL

Do you honestly believe this claim?

>>>>>>>>>>>

TFK bragged about his superior capacity to understand these papers. I predicted he'd fall on his face when trying to answer basic questions about the papers.

We're still waiting, cowboy. Please demonstrate your superior capacities by just answering the questions rather than by providing your resume.

 

[Carll68]

"I have questions specifically about the Bazant studies, so, I have concluded that the best way to get the answers is to ask some dude with the screenname TFK to answer them for me"

 

[twinstead]

Hey, if it's not on some obscure internet forum populated by people you don't know, it doesn't exist.