AE911 Truth's WTC7 Evaluation Computer Modelling Project

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Yes we have established this Mick. And we have also established that you are well aware that Dr Hulsey is expressing movement relative to the CoS.
Is that not the correct way to do this ? Be clear now please.

ADD the net movement of the girder will change depending on the motion of the column. You know this.
And you know that is why i am asking you .

No, really, I have no idea. I just told you that the absolute motion of the column is part of the relative motion of the girder relative to the column. So I'm confused as to why you are asking me about it again.
 
Do you understand what I mean by "absolute motion"? i.e. a motion relative to a fixed global frame of reference, like the ground?
 
Of course I do Mick. What I am asking you about is the C79 movement. Because that will contribute to the net movement required hypothetically by the girder.
truth is that the connection remains intact anyhow.
 
Show me where it is calculated then. Link me to it.
I was telling you what 'relative motion' means. see where I wrote (if any)? I don't know if NIST mentioned the column itself moving. I'm saying IF the column moved they would have just calculated it into the 5.5 (6.2?)number.
 
Of course I do Mick. What I am asking you about is the C79 movement. Because that will contribute to the net movement required hypothetically by the girder.

Are you even reading what I'm writing?

Sorry gerry, but I've told you that exact thing several times.

Relative motion incorporates both absolute motions, and gives you one locally relative motion.
 
I was telling you what 'relative motion' means. see where I wrote (if any)? I don't know if NIST mentioned the column itself moving. I'm saying IF the column moved they would have just calculated it into the 5.5 (6.2?)number.
Almost. What you said in #956 was actually "the seat plate is connected to the column. the column movement (if any) is calculated IN the relative motion number" I don't think that it is. Not by NIST anyhow.
 
No, really, I have no idea. I just told you that the absolute motion of the column is part of the relative motion of the girder relative to the column. So I'm confused as to why you are asking me about it again.
I'm thinking maybe Hulsey said the column moved 2", so they are wondering if NIST found the column itself to move 2" also. like did the girder itself actually move 7.5"

??
 
So how far does the c79 move? You said that the seat plate was the point of reference for NIST but it cannot be. The column moving will either add or subtract to the movement of the girder relative to it. This is actually quite an important point.
You cannot tell the movement of either, but remember NIST said how far the girder moved explicitly when they claimed 6.25" west. The didn't mention the column. So are you going with the column did not move at all ? Or did it move ?

NIST does not give a figure for the absolute motion of column 79 relative to its as-built position (because that figure is irrelevant, as has been pointed out to you ad nauseum), but NIST does note that the column was laterally displaced in its ANSYS damage model:

upload_2017-9-18_14-24-7.png
NIST NCSTAR 1-9 pg. 504.

Did Hulsey even measure how much damage to floors other than 12 and 13 would affect the displacement of column 79 for his irrelevant center of stiffness analysis? No.

Don't skip my question, by the way:

@gerrycan By how many inches would column 79 need to move relative to the initial center of stiffness of floor 13 as calculated by Hulsey for A2001 to fail?

(PS: The reason you cannot answer this question is because your premise makes no sense.)
 
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Are you even reading what I'm writing?

Sorry gerry, but I've told you that exact thing several times.

Relative motion incorporates both absolute motions, and gives you one locally relative motion.

Okay. So do NIST have the column moving IN YOUR OPINION, or to your KNOWLEDGE ? Or do you not know ?
We both know that Dr Hulsey has it moving, and that the connection does not fail.
 
And that was transferred just before the temps, I think. The graph was posted by me on this thread earlier.
The Chapter 12 LS-DYNA model did not compute at all if and how elements deformed and connections failed due to heat.
Not. At. All.
It is entirely, completely irrelevant to the question of how girder A2001 moved on its C79-seat due to the structure being heated.
Entirely. Completely. Irrelevant.

It was the Chapter 11 ANSYS model - and only the Chapter 11 ANSYS model - that computed the response of all those beams, columns, girders and connections in response to being heated.
It was the Chapter 11 ANSYS model - and only the Chapter 11 ANSYS model - that determined that A2001 would be pushed off its seat after 4 hours of Case B heating.

The Chapter 12 LS-DYNA model had no hand whatsoever in finding that the girder walked of.
None. Whatsoever.

The Chapter 12 LS-DYNA model was merely fed the results of the Chapter 11 ANSYS model. Including the finding that A2001 would walk off of its seat. The Chapter 12 LS-DYNA model starts computing after the walk-off is already a done deal.


I think it is vitally important to understand how the various NIST models were set up and how one fed into the next - but not back.
Whatever happened in the Chapter 12 LS-DYNA model has absolutely no bearing of what happens in the Chapter 11 ANSYS model.
Absolutely. None.


I don't know how to express this any clearer. I hope it helps.
 
Okay. So do NIST have the column moving IN YOUR OPINION, or to your KNOWLEDGE ? Or do you not know ?
We both know that Dr Hulsey has it moving, and that the connection does not fail.

NIST said the column moved, see @benthamitemetric, post above.

Hulsey said everything moved together and nothing failed.

So Hulsey said there was a relative motion of 0, it's irrelevant how much things moved if they all move together.

But then he compared his absolute movement of 2" to a relative motion of 6.25", which was wrong.

Hey, if his model says that nothing failed, then why not lead with that?

You know, because it's nonsense.
 
At the end of the day, I am convinced that this "how much did C79 move" slide, you know,with the colored floor plan indicating how far the slab moved relative to ... something, is not actually relative to any Center of Anything but actually to the ground.
I wish to believe that Hulsey did have his model pinned to the ground and not moving frictionless about it.
As deirdre pointed out, CoS changes (moves relative to the ground, or relative to a local coordinate system that you could have drawn on the floor centering on the original CoS) as the material properties (actual stiffness of members) and geometry of the structure changed non-uniformly in response to heating a major portion of the floor. It would have been too complicated, and unnecessary, to actually compute the exact location of the CoS at any time t.

Hulsey says that what he points to is the "thermal centroid", but actually it's simply the region that happens to move least relative to the ground.

I would bet a 20-pack beer on this.
 
@gerrycan you already indicated to me in PM that you and your friends are trolling. so either be super clear and make an actual point in future posts or I'm giving you a timeout from this thread.
 
Mick, you stated that the movement between the elements @ the C79 connection was 0 relative to each other in Dr Hulsey's model.
Bentham has kindly informed us above that NIST did not give any kind of figure for the movement of Column 79 itself, saying "NIST does note that the column was laterally displaced in its ANSYS damage model"

So in NIST's model we know where the elements are relative to each other.

In Dr Hulsey's model we know where they ALL are relative to the CoS.

Do we agree on that ?
 
@gerrycan you already indicated to me in PM that you and your friends are trolling. so either be super clear and make an actual point in future posts or I'm giving you a timeout from this thread.
I never said that at all. I said they were laughing, and probably at my frustration. Nobody is trolling anyone and I have established the point that I was trying to now.
I am not a troll.
 
Mick, you stated that the movement between the elements @ the C79 connection was 0 relative to each other in Dr Hulsey's model.
Bentham has kindly informed us above that NIST did not give any kind of figure for the movement of Column 79 itself, saying "NIST does note that the column was laterally displaced in its ANSYS damage model"

So in NIST's model we know where the elements are relative to each other.

In Dr Hulsey's model we know where they ALL are relative to the CoS.

Do we agree on that ?

Honestly, you could save this thread a lot of dead weight, nonsense posts by simply reading the NIST report yourself instead of making or implying false claims about it that need correcting every 1-2 pages. As I said before, you should cite directly to it every time you reference it. For example, if you wanted to claim to Mick that NIST hadn't modeled the displacement of column 79, you could have cited the portion of the NIST report that you thought supported that notion. What would have happened in reality is that you would have gone hunting for that part of the report and would have realized your error before wasting 2 pages asking Mick about it.
 
Honestly, you could save this thread a lot of dead weight, nonsense posts by simply reading the NIST report yourself instead of making or implying false claims about it that need correcting every 1-2 pages. As I said before, you should cite directly to it every time you reference it. For example, if you wanted to claim to Mick that NIST hadn't modeled the displacement of column 79, you could have cited the portion of the NIST report that you thought supported that notion. What would have happened in reality is that you would have gone hunting for that part of the report and would have realized your error before wasting 2 pages asking Mick about it.
Made my point above Bentham. Thanks for your help.
 
Made my point above Bentham. Thanks for your help.

[paraphrasing] perhaps you can demonstrate the incorrectness of Hulsey's approach to yourself by trying to extrapolate from that point an answer to my question:

@gerrycan By how many inches would column 79 need to move relative to the initial center of stiffness of floor 13 as calculated by Hulsey for A2001 to fail?

(PS: The reason you cannot answer this question is because your premise makes no sense.)
 
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In Dr Hulsey's model we know where they ALL are relative to the CoS.

Do we agree on that ?
Since this question goes to "we", I hope you excuse that I feel included.

No, Hulsey disagrees. he says they move relative to the thermal centroid.
You said that thermal centroid and stiffness centroid are two different things.
(Ok, and next up he says it's the center of stiffness, and that they are the same thing - which is nonsense)

I however believe that, in his slide, movement is in fact stated relative to the ground. But that is really a minor point.

Having said that, we may "know" how the floor slab (the floor slab! the slide does not show columns, girders, beams, it shows a continuous slab!) moved everywhere relative to CoS. With this, we atually also "know" how the slab moves relative to the east wall, or relative to the west wall, or relative to column 79 - because transformation from one coordinate system to another is rather trivial and preserves information 100%.

However, we do not really know if and how girders and beams moved relative to the floor slab. Hulsey makes it appear, and perhaps that is what you really mean when you repeatedly said the other day that "Hulsey modelled the floors as composite", as if slabs and beams CANNOT disconnect (i.e. are modelled such that a failure in the contact is not computationally allowed). Or at least that he finds the DO not disconnect (not sure which it is). Because as soon as you allow for beams, columns, and slab sections to move locally at different rates, one slide to show lateral displacement can't show all that.
 
Since this question goes to "we", I hope you excuse that I feel included.

No, Hulsey disagrees. he says they move relative to the thermal centroid.
You said that thermal centroid and stiffness centroid are two different things.
(Ok, and next up he says it's the center of stiffness, and that they are the same thing - which is nonsense)

I however believe that, in his slide, movement is in fact stated relative to the ground. But that is really a minor point.

No the CoS can change in a building storey by storey.
As I said to Mick, we both know that Dr Hulsey was referring to what we are calling the CoS.
 
@gerrycan By how many inches would column 79 need to move relative to the initial center of stiffness of floor 13 as calculated by Hulsey for A2001 to fail?

(PS: The reason you cannot answer this question is because your premise makes no sense.)

It would have to move South. It's the only one left for it. Can't go North, and if it goes East or West the girder is inside the side plate lip. Stuck.
 
I was gonna say that too. :) (and did in PM)
Mick seems to have worked out the bit of the building that Dr Hulsey was referring to when he said
"The SAP and ABAQUS seem to be measurements of the region around Column 79 relative to a "thermal centroid" near the lower middle of the plan." (my emphasis)

We all know where he is talking about. It's on the presentation. I believe he misspoke. I will find out if and when I can.
 
No the CoS can change in a building storey by storey.
As I said to Mick, we both know that Dr Hulsey was referring to what we are calling the CoS.
Yes, it also changes over time as the structure heats, cools and loses integrity.

And Hulsey says "thermal centroid", and then goes on to imply that it's the same as stiffness centroid. Which is nonsense. You said yourself that they are different.

Hulsey is very confused here. "Thermal centroid" is not even a thing. "Center of thermal expansion" is. And if anything, that is what his model can potentially find when he heats it and it expands in response to thermal loading. What you do not, and cannot, find in that modelling is the Center of Stiffness. Why? Because the Center of Stiffness is the the point that a plane (diaphragm, floor) rotates about when subjected to a uniform (or perhaps put better: centered on its Center of Mass) lateral force, such as seismic force or wind. Hulsey does not at all analyse torsion, and so his model cannot find the Center of Stiffness.

So all this talk of CoS, in Hulsey's presentation or on the last several pages here, is nonsense, as that is simply not what his model is basing its coordinate system on.

If anything, his initial term "thermal centroid" might be a realistic candidate, if you correct the term to "center of thermal expansion", because that's what the model actually computes.

But in reality, I would bet a 20-pack of beer that his slide actually shows movement relative to the ground. This bet is based on the reasonable assumption that Hulsey models the lower end of columns as fixed to the ground. If he doesn't, and has them floating freely, then all bets are off, literally, as we would then be dealing with a really inept model.
 
It would have to move South. It's the only one left for it. Can't go North, and if it goes East or West the girder is inside the side plate lip. Stuck.
Perhaps - but by how many inches relative to the CoS? That is the point. Can you tell from Hulsey's numbers and the expansion slide?
 
I don't understand where you are going with this.

It's to demonstrate Mick's point that Hulsey's approach makes no sense given what he was trying to measure--whether A2001 could have failed. Hulsey's measurement of the movement of column 79 relative to the center of stiffness cannot tell you that. NIST's measurement of the movement of the south end of A2001 relative to its bearing seat (taking into account the movement of column 79) can. @gerrycan cannot simply answer the question because of the obvious flaw in Hulsey's approach. To answer the question, he needs to know exactly what NIST measured.
 
I don't understand where you are going with this.
Perhaps you tried to answer the question and found it is impossible to answer, given the data that Hulsey presented? Then that is exactly the point: Hulsey's stating movement relative to CoS gives us no criterion to decide if there would be girder walk-off or not, for the resulting numbers are as arbitrary and meaningless as choosing CoS as origin of your coordinate system.

The only sensible answer we can give is that the girder needs to move 6.25 inches east relative to Column 79.
or you could say, equivalently, that C79 needs to move 6.25 inches relative to the girder's end.

Of course, an equivalent statement would be: Given that C79 mover 1.9 inches east relative to CoS, the girder's end would have to move 4.35 inches west.
 
Of course, an equivalent statement would be: Given that C79 mover 1.9 inches east relative to CoS, the girder's end would have to move 4.35 inches west.

You can't mix and match data from the FEAs. In Dr Hulsey's model where the column moves to the East, the connection stays intact. The floor is actually what moves the whole thing.
The girder is not free in that analysis to move West.
 
So NIST did not say EXACTLY what they measured. thanks for that.
FALSE.

They determined that the end of A2001 moved 6.25 inches west relative to its bearing seat, that is relative to C79.

And that number was actually an explicit criterion. under NIST's approach, it was possible at the outset to say what that number is.

In Hulsey's approach, we do not know that number. Prior to runing the model, no criterion could have been established by which to determine if the girder walks of or not, if all you do is state movement relative to CoS.

This fact is demonstrated by your inability to answer bentamite's question: "How many inches in your chosen direction would it have to move relative to the center of stiffness?"
 
And Hulsey says "thermal centroid", and then goes on to imply that it's the same as stiffness centroid. Which is nonsense. You said yourself that they are different.

Hulsey is very confused here. "Thermal centroid" is not even a thing. "Center of thermal expansion"
from my reading they are all the same thing. if they are being used in the proper context. or at least I understand why Hulsey might be using the terms interchangeably, even though it might be confusing.
 
FALSE.

They determined that the end of A2001 moved 6.25 inches west relative to its bearing seat, that is relative to C79.
But the also said that C79 moved laterally, as referenced above by Bentham. point being that you don't know in what direction.
 
So NIST did not say EXACTLY what they measured. thanks for that.

What? This does not make sense. NIST stated exactly what its failure criterion was. Hulsey did not. In any case, the movement of column 79 relative to the center of stiffness cannot be a precise failure criterion, which is why you cannot answer the question.
 
You can't mix and match data from the FEAs.
Thanks for making our point! Now explain that to your laughing friends and to Hulsey, who mixes 1.9 inches in his FEA from CoS with NIST's 5.5 inches from C79!

In Dr Hulsey's model where the column moves to the East, the connection stays intact. The floor is actually what moves the whole thing.
The girder is not free in that analysis to move West.
Hold on - is that a model input? Is the model defined such that "the girder is not free in that analysis to move West"?
 
Thanks for making our point! Now explain that to your laughing friends and to Hulsey, who mixes 1.9 inches in his FEA from CoS with NIST's 5.5 inches from C79!
He compares his output result to NIST's.
The difference is that we know where ALL the elements are in Dr Hullsey's relative to one fixed point.
For NIST we only know where they are relative to each other.

Hold on - is that a model input? Is the model defined such that "the girder is not free in that analysis to move West"?
No that would be the COMBIN37 element in NIST's model that you're getting confused with there. It is unidirectional.
 
But the also said that C79 moved laterally, as referenced above by Bentham. point being that you don't know in what direction.
Huh? For some reason the words "eastward lateral displacement of Column 79" appear on my retina when I read benthamite's reference. Strange, huh?

But it doesn't really matter what C79's motion was relative to the ground, the CoS, the CoTE, the Staten Island Ferry or the ISS.
All that matters is how it moves relative to the end of A2001.
And that NIST defined very exactly, and monitored in their Chapter 11 ANSYS model, and they gave the exact number of inches they needed for walk off.

On the other, neither you nor Hulsey can say how much any one element would have to move relative to CoS to fail. As you demonstrate time and again by not saying how much any one element would have to move relative to CoS to fail.
 
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