Merged Applicability of Bazant's model to the real world

[ergo]

What does 911 truth call a floor that can hold up to 29,000,000 pounds? (like 29 million pounds)

little resistance!

Well, that was a NIST quote. But hey, have you informed femr2 of the 29,000,000 pound-resisting floors?

 

[beachnut]

Yes, curious. So now I understand the welded gusset plates and the bolted truss to truss-seats. Still not clear on how either of these could be distinguished as a "horizontal connection" versus a "floor/wall connection", since they are both obviously both. But I think I've made my point and won't belabour it.

What is interesting is your statement about the rebar from the concrete slabs welded onto the columns. I did not know about this. Is this common knowledge?

Well, that was a NIST quote. But hey, have you informed femr2 of the 29,000,000 pound-resisting floors?

It is a fact, as in what a typical floor can hold. femr2 has delusions of CD, he is not trying to learn, he is trying to back in CD. What are your numbers for what a floor can hold? What is wrong with the NIST number?


What does this have to do with Bazant's model?
What does your delusion have to do with Bazant's model?

 

[Baylor]

That reminds me, it's almost time for my Count Heiwa avatar.

 

[R.Mackey]

What does 911 truth call a floor that can hold up to 29,000,000 pounds? (like 29 million pounds)

little resistance!

Do you make up these definitions as you go, or does Gage hand them out when you join his spread the lies travel club?

For the record, 29 million pounds is the amount of force required to fail all of the wall connections simultaneously for an entire floor -- it's the "best case" load, wildly optimistic in most situations. The actual buckling strength of the floors is somewhere in the 3 to 6 million pound range, around 300 PSF. Heated, less than that. Penetrating loads, about 450 pounds per square foot will cause local floor failures even if the overall capacity is not exceeded.

And that counts the weight of the floors themselves, which is about 48 PSF.

This can all be worked out from NCSTAR1-6B, where sections of floor were built to original specs and destructively evaluated.

 

[ergo]

So, what about this column-welded rebar?

Anyone? Enquiring minds want to know!

 

[femr2]

Well, that was a NIST quote. But hey, have you informed femr2 of the 29,000,000 pound-resisting floors?

That's about 11 times it's own mass, so it's a fair bit over.

About 10,000,000 lbs is more reasonable.

Not sure where Ryans figures (3 to 6) come from.

OOS floorspace = ~31100 sq.ft

The upper block mass (WTC1) was ~3.6E+07 Kg = ~79,600,000 lbs

 

[beachnut]

That reminds me, it's almost time for my Count Heiwa avatar.

Every time I see OOS, I think of the failed idiotic CD delusion Major Tom, femr2, Tony and the other 911 truth faithful have. The mark of woo, OOS.

Count? Can 911 truth do math?

Threads about Bazant's work expose 911 truth's ignorance on models. Like flypaper.

 

[Newtons Bit]

That's about 11 times it's own mass, so it's a fair bit over.

About 10,000,000 lbs is more reasonable.

Not sure where Ryans figures (3 to 6) come from.

OOS floorspace = ~31100 sq.ft

The upper block mass (WTC1) was ~3.6E+07 Kg = ~79,600,000 lbs

The 29,000k number comes from the NIST FAQ which is impossible for most truthers to quote or talk about accurately.

 

[femr2]

The 29,000k number comes from the NIST FAQ which is impossible for most truthers to quote or talk about accurately.

And that has what to do with my post ?

Ryan suggests 3 to 6 million. I'm suggesting 10 million.

If you think it's worth repeating the source of the 29 million figure which is, how did Ryan put it..."the "best case" load, wildly optimistic in most situations", when I suggest 10 million as a more reasonable value, then may I suggest you have a quick word with Ryan too

 

[Newtons Bit]

And that has what to do with my post ?

Ryan suggests 3 to 6 million. I'm suggesting 10 million.

If you think it's worth repeating the source of the 29 million figure which is, how did Ryan put it..."the "best case" load, wildly optimistic in most situations", when I suggest 10 million as a more reasonable value, then may I suggest you have a quick word with Ryan too

Whoa, I totally misread your post. My bad!

 

[femr2]

Whoa, I totally misread your post. My bad!

No worries.

I think values in Joules are more useful for this metric though.

Current estimate I'm aware of is in the order of 70MJ.

Good/bad value ?

 

[Newtons Bit]

No worries.

I think values in Joules are more useful for this metric though.

Current estimate I'm aware of is in the order of 70MJ.

Good/bad value ?

It doesn't seem obscenely high. How are you calculating it?

 

[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.

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"

 

[femr2]

It doesn't seem obscenely high. How are you calculating it?

Was another member of the911forum, but shear of the truss connections IIRC. (core and perimeter)

The idea of one load causing failure is a bit theoretical IMO

I agree. Energetics based values are more useful, as they can be determined per-connection if needs be, and help abstract from factors such as velocity.

The mark of woo, OOS.

Looks like you're on your own there. Quite why no-one pulls you for your ridiculous comments is beyond me, but if it floats your boat, meh.

 

[R.Mackey]

Whoa, I totally misread your post. My bad!

We talked about this last year. I got that estimate from NCSTAR1-6B, where (going from memory, figures are not precise, verify before using!) they load the test floor samples to 150% of design and heat to failure. From the added load, and understanding the ratio between design and ultimate, you work out the ultimate load of the floor. Before I eyeballed it at 300 PSF.

I'm comfortable with 10 million pounds as a ROM modeling number, particularly in a dynamic situation. I just wanted to clarify that 29 million pounds refers to something a little bit different.

 

[beachnut]

... Looks like you're on your own there. Quite why no-one pulls you for your ridiculous comments is beyond me, but if it floats your boat, meh.

I would rather be on my own than in 911 truth repeating lies, unable to understand 911 after 9 years of failure.

What journals will OOS and the delusional CD be in? The CD delusion boat sunk on 911, news travels slow to 911 truth, delayed over 9 years.

Bazant's model was published when?¹ Why can't 911 truth get published? 911 truth has problems with understanding 911, like your flight 175 multiple plane misunderstanding.

It comes down to what is real engineering and what is not. Bazant's model applies to the real world, the delusional CD claims of 911 truth don't.

OOS means delusional CD claims are coming; read the OOS paper again. Are you helping MT with the math, or the publishing? It appears engineers like Bazant can model on a napkin in minutes, be published and respected. 911 truth can't get past delusions of CD and other nonsense after 9 years given the answers and evidence.


1. 2 days for Bazant (9/13/01), never for 911 truth. 911 truth can't do much but make up lies.

911 truth includes you and others with the CD delusion, and other failed claims like two flight 175s; those who fail to research, or produce reality based work with reality based goals.

http://web.archive.org/web/20011031095744/http://www.tam.uiuc.edu/news/200109wtc/

 

[femr2]

I would rather be on my own than in a movement pushing lies. meh

Don't strain. Am sure some dia-calm will sort you out.

It comes down to what is real engineering and what is not. Bazant's model applies to the real world

Classic beachnut. May I suggest beginning by reading the thread title ?

911 truth

I assume you mean AE911T, and must say you seem awfully obsessed with them. Perhaps you should contact them rather than spamming every one of your posts with references to them.

 

[Tony Szamboti]

Yes, curious. So now I understand the welded gusset plates and the bolted truss to truss-seats. Still not clear on how either of these could be distinguished as a "horizontal connection" versus a "floor/wall connection", since they are both obviously both. But I think I've made my point and won't belabour it.

What is interesting is your statement about the rebar from the concrete slabs welded onto the columns. I did not know about this. Is this common knowledge?

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.

The damper units would have also provided for some horizontal connection strength as they had an ultimate strength of 40,000 psi and I think that was for a 1/2" diameter rod which would allow it to resist forces up to about 7,800 lbs.

 

[leftysergeant]

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.

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"

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.

When I mentiond that I saw two differnt structures in one involved, femr2 wanted to call it four. For the purposes of examining Bazant, I think we can treat the floors and perimeter columns as a single unit.

The cores and their dividing floors followed a totally separate career once things started miving.

Once collapse was initiated, another force came into play in the air pressure and the turbidity flow that the dust plumes set up to further press the perimeter columns outward. Ryan Mackey contributed a formula to determine how much force this might involve, but I lack the math skills to do much with it. It just looks to me like an awesome amount of energy that needs to be considered.

I will stand by my assertion that, after collapse was initiated, it was the collisions and mechanical resonnance that took down the cores.

 

[femr2]

Bazant came up with a good way to determine whether the minimum energy neccessary for the task was available.

No he didn't. Quite far from minimum. Was that an oops or do you not understand the scope of the limiting case ?

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.

No, it an energetics based limiting case mathematical model. This thread is specifically about making sure people don't misapply it. You are. Suggest re-reading the thread from the beginning.

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.

Looks like you have actually gotten around to reading the ROOSD study. I don't know why more of you guys don't spend more time reading the work done over at the911forum. This kind of stuff has been discussed there for years.

When I mentiond that I saw two differnt structures in one involved, femr2 wanted to call it four. For the purposes of examining Bazant, I think we can treat the floors and perimeter columns as a single unit.

I don't agree. And by the fact that you have just described separate modes of destruction between floor slabs and perimeter, you should not be separating them.

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.

The cores and their dividing floors followed a totally separate career once things started miving.

Sorry to make the point, but it seems that the content of your post basically contains a slight rewording of what other people (including myself) posted a little while earlier. Odd.

Once collapse was initiated, another force came into play in the air pressure and the turbidity flow that the dust plumes set up to further press the perimeter columns outward.

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.

I will stand by my assertion that, after collapse was initiated, it was the collisions and mechanical resonnance that took down the cores.

I think you'll have to present an awful lot more detail before it becomes more than assertion.

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.

That is speculation though, and much more detail would need to be provided for me to say that is what happened.