# Could Girder A2001 Possibly Have got Past the Side Plate on Column 79?

#### Christopher 7

##### Active Member
@Christopher 7, in the calculations you've presented re the expansion of A2001 at 400°C, is it your assumption that the entire beam was continuously heated to a single, uniform temperature?
Good point. But even at an average temperature of a little over 200 °C, the A2001 girder would be pushed up against the face of column 79 and could not get by the side plate.

center line of A2001 girder to face of column 79 - 1-3/4 inches
girder flange 11-1/2 inches wide divided by 2 = 5-3/4 inches
east end of girder flange 5-3/4 inches from girder center line
angle is 7/8:12 or 7/16 in 6 inches so:
1-3/4 – 7/16 = 1-5/16
east end of girder flange just over 1-5/16 inches from column face

A2001 girder 45 feet
K3004 floor beam 53.57 feet – expands 2.325 inches at 300 °C
45 divided by 53.75 = .837
45 is 83.7% of 53.75
2.325 x .837 = 1.946 or 1-15/16 inches

Net expansion of K3004 at 600°C is 5.392 x .837 = 4.51
Net expansion of K3004 at 500°C is 4.348 x .837 = 3.64
Net expansion of K3004 at 400°C is 3.307 x .837 = 2.77
Net expansion of K3004 at 300°C is 2.325 x .837 = 1.95
Net expansion of A2001 at 200°C average temperature would be a little over 1 inch.

(Note that I am leaving aside the other points you raised, such as the ridiculous claim that the concrete decks and steel framing members would in all temperature conditions act in unison
Another good point.
Everything would expand together until connections started to fail.
The concrete decks and columns would act in unison unless the concrete deck was crushed in compression. But that did not happen in the NE corner of floor 13.

#### Oystein

##### Senior Member
Thanks, Christopher, for affirming that you work from unrealistic assumptions regarding the behavior of complex steel frame structure in severe fires.

You apply your math to unrealistic models.
You see, the "uniform" expansion would have different patterns on different floors, which would stress the columns and indeed push them around. And you still completely disregard sagging beams and girders, which no longer have net expansion. You, as well as Hulsey, disregard cooling cycles, which too would go the opposite way of expansion.

#### Oystein

##### Senior Member
...
The concrete decks and columns would act in unison unless the concrete deck was crushed in compression. But that did not happen in the NE corner of floor 13.
How do you know?

#### benthamitemetric

##### Senior Member
Good point. But even at an average temperature of a little over 200 °C, the A2001 girder would be pushed up against the face of column 79 and could not get by the side plate.

center line of A2001 girder to face of column 79 - 1-3/4 inches
girder flange 11-1/2 inches wide divided by 2 = 5-3/4 inches
east end of girder flange 5-3/4 inches from girder center line
angle is 7/8:12 or 7/16 in 6 inches so:
1-3/4 – 7/16 = 1-5/16
east end of girder flange just over 1-5/16 inches from column face

A2001 girder 45 feet
K3004 floor beam 53.57 feet – expands 2.325 inches at 300 °C
45 divided by 53.75 = .837
45 is 83.7% of 53.75
2.325 x .837 = 1.946 or 1-15/16 inches

Net expansion of K3004 at 600°C is 5.392 x .837 = 4.51
Net expansion of K3004 at 500°C is 4.348 x .837 = 3.64
Net expansion of K3004 at 400°C is 3.307 x .837 = 2.77
Net expansion of K3004 at 300°C is 2.325 x .837 = 1.95
Net expansion of A2001 at 200°C average temperature would be a little over 1 inch.

Another good point.
Everything would expand together until connections started to fail.
The concrete decks and columns would act in unison unless the concrete deck was crushed in compression. But that did not happen in the NE corner of floor 13.

If the beam and the floor are acting in unison at all times, how can the beam move at all relative to the column (by thermal expansion or otherwise) such that it could close the gap and be trapped by the side plate? Is the concrete floor failing by compression at the point just next to column 79 above A2001 in Hulsey's model? Please provide a citation to where this is analyzed and discussed in Hulsey's report.

And if a beam is heated unevenly, will its pattern of expansion simply be in one direction along its length, or might it become distorted, effectively limiting the total net lengthwise expansion?

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#### Christopher 7

##### Active Member
Thanks, Christopher, for affirming that you work from unrealistic assumptions regarding the behavior of complex steel frame structure in severe fires.
Not so, and that is a personal insult. Stick to the arguments please.
They were not severe fires. They were normal building fires.
You apply your math to unrealistic models.
Not so. The math is constant, regardless of which model. The girders and floor beams expand at a given rate in relation to the rise in temperature.

You see, the "uniform" expansion would have different patterns on different floors, which would stress the columns and indeed push them around.
The amount is insignificant. There was less that 2 inches of expansion of the floor slab at column 79 on floor 13.
And you still completely disregard sagging beams and girders, which no longer have net expansion.
Not so. At 400 °C, the floor beams would sag less than an inch creating a loss in length of 0.003 inches which is negligible.
You, as well as Hulsey, disregard cooling cycles, which too would go the opposite way of expansion.
The amounts are insignificant except for the east exterior wall
The concrete decks and columns would act in unison unless the concrete deck was crushed in compression. But that did not happen in the NE corner of floor 13.
How do you know?
They could not do otherwise. The concrete decks trap the columns.
If the beam and the floor are acting in unison at all times, how can the beam move at all relative to the column (by thermal expansion or otherwise) such that it could close the gap and be trapped by the side plate?
According to NIST, the shear studs had failed on the floor beams, allowing them to move independently of the slab.
And, according to NIST, there were no shear studs on the girders so A2001 could also move independently of the slab.
The fire was burning south to north so the area around column 79 would be heated before the area around column 44.
Further, according to NIST:
The simple shear connection between Column 79 and the girder that spanned the distance to the north face (to Column 44) failed on Floor 13. The connection failed due to shearing of erection bolts, caused by lateral thermal expansion of floor beams supporting the northeast floor system and, to a lesser extent, by the thermal expansion of the girder connecting Columns 79 and 44. NCSTAR 1-9, Vol. 2, p. 611 [PDF p. 273/677]
Content from External Source
Is the concrete floor failing by compression at the point just next to column 79 above A2001 in Hulsey's model?
No
And if a beam is heated unevenly, will its pattern of expansion simply be in one direction along its length, or might it become distorted, effectively limiting the total net lengthwise expansion?
As noted above, the bolts at column 79 failed before the bolts at column 44 so all the expansion of A2001 was toward column 79 until it was wedged up against the face of column 79. Since the fire was burning south to north, the beams closest to column 79 were heated first. This would result in the floor beams pushing A2001 to the west in a south to north succession which would minimize any distortion of A2001.

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#### benthamitemetric

##### Senior Member
They could not do otherwise. The concrete decks trap the columns.

According to NIST, the shear studs had failed on the floor beams, allowing them to move independently of the slab.
And, according to NIST, there were no shear studs on the girders so A2001 could also move independently of the slab.
The fire was burning south to north so the area around column 79 would be heated before the area around column 44.
Further, according to NIST:
The simple shear connection between Column 79 and the girder that spanned the distance to the north face (to Column 44) failed on Floor 13. The connection failed due to shearing of erection bolts, caused by lateral thermal expansion of floor beams supporting the northeast floor system and, to a lesser extent, by the thermal expansion of the girder connecting Columns 79 and 44. NCSTAR 1-9, Vol. 2, p. 611 [PDF p. 273/677]
Content from External Source
No

As noted above, the bolts at column 79 failed before the bolts at column 44 so all the expansion of A2001 was toward column 79 until it was wedged up against the face of column 79. Since the fire was burning south to north, the beams closest to column 79 were heated first. This would result in the floor beams pushing A2001 to the west in a south to north succession which would minimize any distortion of A2001.

So, contrary to what you’ve repeatedly claimed, you actually now agree with NIST that the beams in the floor system, including A2001, will move independently from the concrete deck in some circumstances and that such circumstances were more than likely than not to have occurred? So aren’t we back to square one re determining whether the floor system expansion to the north and west of column 79 would have moved that column relative to A2001 in a way that allowed A2001 to pass the side plate? How can you in one argument say that such movement could not be significant due to the uniform movement of the entire floor system and then just a few posts later claim you agree with NIST that A2001 was likely no longer acting compositely with the floor and thus no longer bound from the nonsense uniform movement you claimed prevented such movement by constraining the entire floor system?

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#### Christopher 7

##### Active Member
So, contrary to what you’ve repeatedly claimed, you actually now agree with NIST that the beams in the floor system, including A2001, will move independently from the concrete deck in some circumstances and that such circumstances were more than likely than not to have occurred?
I don't agree with NIST. I'm just using their report to prove that their scenario is not possible. In actual fact, none of this happened. But that's a subject for another thread.

I did have to change my original statement by including modifiers.
There would be movement due to thermal expansion but everything would expand together.
The concrete decks and columns would act in unison unless the concrete deck was crushed in compression. But that did not happen in the NE corner of floor 13.
Everything would expand together until connections started to fail.
Thank you for calling my attention to my oversight. The statement should be:
Everything would expand together until connections or the shear studs failed, or a slab was crushed.
The columns and slab would expand together until the slab was crushed, regardless of shear studs or connections failing.
So aren’t we back to square one re determining whether the floor system expansion to the north and west of column 79 would have moved that column relative to A2001 in a way that allowed A2001 to pass the side plate?
Column 79 is in the center of the pale green which means that it was displaced about 1-3/4 inches from the center of the building.
Column 44 is in the yellow area and closer to the pale green than the pale orange so it was displaced abut 1-1/4 inches from the central point.
That would put the area between columns 79 and 44 in compression.
How can you in one argument say that such movement could not be significant
One half inch difference between the movement of column 79 and the movement of column 44 is insignificant.
and then just a few posts later claim you agree with NIST that A2001 was likely no longer acting compositely with the floor
I don't agree with NIST. I'm just giving their scenario which is:
Additional factors that contributed to the failure of the critical north-south girder were (1) the absence of shear studs NCSTAR 1A p. 53/54 [PDF p. 95/96]
Content from External Source
But we are getting away from the point of this thread which is:
The A2001 girder could not get past the side plate on column 79 because it was wedged up against the face of column 79.

You have asked a lot of questions but you have offered nothing to rebut this.

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#### Oystein

##### Senior Member
Not so, and that is a personal insult. Stick to the arguments please.
What? No insult, just my judgement of the merits of what you wrote.

They were not severe fires. They were normal building fires.
In what world are you living??
There is no contradiction between "severe fire" and "office fire". Office fires can be severe. The "normal office fires" were "normal" only in the sense that they had no unusual fuel loading, fuel types or accelerants.
Lots of other circumstances around those fires of course were highly "unnormal", such as the lack of water supplies and the prior death of 343 firefighters, circumstances that allowed these normal office fires to grow and grow and grow and get fully involved on sic of seven very large consecutive floors, making them in effect the largest office fires in US history.

Not so. The math is constant, regardless of which model.
Math applied to a wrong model leads to invalid results. Agreed, or not agreed?

Example: Suppose we modeled WTC7 as a fire-breathing, six-legged dinosaur with a fatty tail, and we applied math very rigorously and correctly to every aspect of that model - would you accept the results as useful?

The girders and floor beams expand at a given rate in relation to the rise in temperature.
That's only one of the many things they do in a severe, wandering fire, when there are different fire scenarios on consecutive floors. You see, they also bend, contract, sag, break connections, become un-composite with the floor slabs, etc.

The amount is insignificant. There was less that 2 inches of expansion of the floor slab at column 79 on floor 13.
Bare assertion; assuming the consequent

Not so. At 400 °C, the floor beams would sag less than an inch creating a loss in length of 0.003 inches which is negligible.
Is assuming a single temperature of 400 °C not a bit of a fire-breathing, six-legged dinosaur with a fatty tail?

The amounts are insignificant except for the east exterior wall
How do you know?

They could not do otherwise. The concrete decks trap the columns.
Until the concrete cracks. Which you don't know when that will happen.

According to NIST, the shear studs had failed on the floor beams, allowing them to move independently of the slab.
And, according to NIST, there were no shear studs on the girders so A2001 could also move independently of the slab.
The fire was burning south to north so the area around column 79 would be heated before the area around column 44.
Further, according to NIST:
The simple shear connection between Column 79 and the girder that spanned the distance to the north face (to Column 44) failed on Floor 13. The connection failed due to shearing of erection bolts, caused by lateral thermal expansion of floor beams supporting the northeast floor system and, to a lesser extent, by the thermal expansion of the girder connecting Columns 79 and 44. NCSTAR 1-9, Vol. 2, p. 611 [PDF p. 273/677]
Content from External Source
I don't understand the significance of this either in the context of our most recent discussion or of the thread topic, especially seeing that you don't even accept what NIST wrote. Can you explain? Or better yet, just pull this paragraph and admit you blew hot air?

#### benthamitemetric

##### Senior Member
I don't agree with NIST. I'm just using their report to prove that their scenario is not possible. In actual fact, none of this happened. But that's a subject for another thread.

I did have to change my original statement by including modifiers.

Thank you for calling my attention to my oversight. The statement should be:
Everything would expand together until connections or the shear studs failed, or a slab was crushed.
The columns and slab would expand together until the slab was crushed, regardless of shear studs or connections failing.

One half inch difference between the movement of column 79 and the movement of column 44 is insignificant.

I don't agree with NIST. I'm just giving their scenario which is:
Additional factors that contributed to the failure of the critical north-south girder were (1) the absence of shear studs NCSTAR 1A p. 53/54 [PDF p. 95/96]
Content from External Source
But we are getting away from the point of this thread which is:
The A2001 girder could not get past the side plate on column 79 because it was wedged up against the face of column 79.

You have asked a lot of questions but you have offered nothing to rebut this.

Hmmmmm. You also previously wrote:

Bending and sagging floor beams and girders could NOT push the columns around because the columns were surrounded by cement slabs. There would be movement due to thermal expansion but everything would expand together.

Your whole argument re the impossibility of A2001 getting past the side plate rests on the assumption that A2001 and column 79 (and "everything" -- your emphasis -- in the entire surrounding floor system) moved together. And then when I asked you how it would be possible for A2001 to close the gap with column 79 if everything was moving together, you cited NIST's observation that, in NIST's model, A2001 decoupled from the floor deck and did not move together with the rest of the floor system. Now you are back tracking and claiming you don't believe the NIST quote you just proffered. So, which is it: in an actual traveling fire scenario, would everything in the local structural system always necessarily move together in perfect unison or could column 79 have moved relative to A2001?

Not only is this point on topic--it is actually the lynch pin of the whole discussion.

#### Christopher 7

##### Active Member
Your whole argument re the impossibility of A2001 getting past the side plate rests on the assumption that A2001 and column 79 (and "everything" -- your emphasis -- in the entire surrounding floor system) moved together.
No.
It was impossible for A2001 to get by the side plate on column 79 because thermal expansion forced it up against the face of column 79.

#### benthamitemetric

##### Senior Member
No.
It was impossible for A2001 to get by the side plate on column 79 because thermal expansion forced it up against the face of column 79.

So in that specific circumstance, you believe that A2001 did not simply move in unison with column 79. If they were moving in unison, the beam would never get closer to the column.

No. [ed: column 79 could not have moved relative to A2001]

But then in the very next post you believe that column 79 couldn’t move in a manner that wasn’t in unison with A2001.

Do you not see the self-serving contradiction in these stances?

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#### Christopher 7

##### Active Member
So in that specific circumstance, you believe that A2001 did not simply move in unison with column 79
(I don't believe that any of this happened. I'm speaking theoretically about what NIST claimed happened.)

A2001 moved in unison with column 79 as the floor slabs expanded.

NIST claims that there were no shear studs on the A2001 girder. So when the seat and top clip bolts broke at column 79, the thermal expansion of A2001 pushed it up against the face of column 79.
If they were moving in unison, the beam would never get closer to the column.
I surprised that you seem to have forgotten about the thermal expansion of the A2001 girder.
Thermal expansion of A2001 is what pushed it up against the face of column 79.

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#### benthamitemetric

##### Senior Member
(I don't believe that any of this happened. I'm speaking theoretically about what NIST claimed happened.)

A2001 moved in unison with column 79 as the floor slabs expanded.

Ok, so where exactly does NIST say that the movement of A2001 and floor slabs was in unison with column 79?

NIST claims that there were no shear studs on the A2001 girder. So when the seat and top clip bolts broke at column 79, the thermal expansion of A2001 pushed it up against the face of column 79.

Oh, I see--so, in other words, NIST observed that A2001 did not move in unison with column 79.

I surprised that you seem to have forgotten about the thermal expansion of the A2001 girder.
Thermal expansion of A2001 is what pushed it up against the face of column 79.

In your imaginary world where everything moved in unison, if A2001 expanded, then it and the adjoining floor system would have necessarily pushed column 79 in the same direction of that expansion by the exact same distance as the magnitude of that expansion.

But you're now trying to have this argument all ways--adopting NIST's observations in part, misrepresenting those same observations flagrantly when convenient, and then ultimately rejecting those observations, both in their correct and misrepresented forms.

Even assuming the strongest form of your argument, which, disregarding the potential torsional buckling or other damage to, or the uneven expansion or cooling cycle of, A2001 that you do not take into account at all, boils down to "a little over an inch of expansion" of A2001 effectively trapping A2001 against the side plates of column 79, that argument still relies on an assumption that column 79 could not have moved relative to A2001 (or else even "a little over an inch of expansion" could be insufficient to cause trapping). You justify that assumption with your magical uniform movement theory, but not only is that theory without any empirical support and in fact contradicted by what was observed in the only two fulsome simulations conducted to date of the effects of the observed roaming fires in WTC7 (by NIST and Wiedlinger, respectively--Hulsey, in stark contrast, did not even test roaming fires), it is clearly counter to the assumptions you need to accept for you to believe that A2001 could move relative to column 79--namely, that the elements within the local system could decouple due to localized failures and move independently of each other.

So how long are you going to keep up this charade of pretending that you don't understand that it is just gobsmackingly obvious that column 79 could have moved relative to A2001?

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#### Christopher 7

##### Active Member
Oh, I see--so, in other words, NIST observed that A2001 did not move in unison with column 79.
No.
Your ability to misinterpret what I have said is astounding.
Column 79 and girder A2001 moved in unison as the concrete floor slab expanded.
But separately from that, A2001 expanded axially as it heated up. At a little above 200 °C , A2001 would have expanded enough to bring it in contact with the face of column 79. Thus trapping it behind the side plate of column 79.

#### Oystein

##### Senior Member
Column 79 and girder A2001 moved in unison as the concrete floor slab expanded.
This describes a continuous function

But separately from that, A2001 expanded axially as it heated up. At a little above 200 °C , A2001 would have expanded enough to bring it in contact with the face of column 79.
This describes a discontinuity.

Such discontinuities occur wherever a connection fails. Connections were liable to fail all over the place - including connections to C79 on other sides, or on the far end of connections framing into C79, both on the same 13th floor and floors above and below.
Which means C79 may have been pushed or pulled away from where it would be had it moved in unison with the (so you assume without good reason) smoothly expanding 13th floor slab.

You do not take this into account.

#### benthamitemetric

##### Senior Member
No.
Your ability to misinterpret what I have said is astounding.
Column 79 and girder A2001 moved in unison as the concrete floor slab expanded.
But separately from that, A2001 expanded axially as it heated up. At a little above 200 °C , A2001 would have expanded enough to bring it in contact with the face of column 79. Thus trapping it behind the side plate of column 79.

This is a total cop out answer that just repeats the same contradiction that I painstakingly outlined for you. You cannot have it both ways and need to accept that, because the elements of the local structure system did not at all times move in unison--a fact that is undeniable and that you have now conceded--any determination of whether A2001 could walk off needs to take into account the movement of column 79 relative to A2001. This destroys your entire analyses of the likelihood that A2001 would be trapped at any given lengthwise expansion as you fail to take that into account.

I can even make it clearer using your own oversimplified facts from this thread: you say the movement of the floor slab, column 79 and A2001 were unison until A2001 separated at some unspecified time. That means you believe that at some point in time, column 79 was being pushed southwest by the floor slab a significant distance. That pushing by itself could prevent A2001 from being trapped when it expanded, and I'll add that even after A2001 expanded enough to decouple, the floor slab above it was also going to continue to expand and push the column as well, lessening A2001's chances of being trapped. And then the fire moved north, northwest and west, expanding the floor system to push the column 79, which you readily admit was at such time decoupled from A2001, south and then southeast and then east. It's the exact series of column movements that could cause A2001 to walk off the west side of its seat. (NIST even expressly notes that column 79 was being pushed to the east when walk off occurred in its model.)

Can you rule that out? No. Because you don't know where column 79 was relative to A2001 during these events, either in NIST's simulation or reality, and your terribly oversimplified girder expansion analyses doesn't even try to take its location into account at all.

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#### Christopher 7

##### Active Member
This describes a discontinuity.

That is just an attempt to disregard the obvious by playing with semantics.
Such discontinuities occur wherever a connection fails. Connections were liable to fail all over the place - including connections to C79 on other sides, or on the far end of connections framing into C79, both on the same 13th floor and floors above and below.
Which means C79 may have been pushed or pulled away from where it would be had it moved in unison with the (so you assume without good reason) smoothly expanding 13th floor slab.
Incorrect. The only thing that would determined the distance between columns 79 and 44 is the concrete slab between them. That is axiomatic. Other failures, expansions or contractions would have no effect on the distance between columns 79 and 44. You are just speculating with no data to support your assertion.

#### Christopher 7

##### Active Member
This is a total cop out answer that just repeats the same contradiction that I painstakingly outlined for you. You cannot have it both ways and need to accept that, because the elements of the local structure system did not at all times move in unison--a fact that is undeniable and that you have now conceded--any determination of whether A2001 could walk off needs to take into account the movement of column 79 relative to A2001. This destroys your entire analyses of the likelihood that A2001 would be trapped at any given lengthwise expansion as you fail to take that into account.

I can even make it clearer using your own oversimplified facts from this thread: you say the movement of the floor slab, column 79 and A2001 were unison until A2001 separated at some unspecified time. That means you believe that at some point in time, column 79 was being pushed southwest by the floor slab a significant distance. That pushing by itself could prevent A2001 from being trapped when it expanded, and I'll add that even after A2001 expanded enough to decouple, the floor slab above it was also going to continue to expand and push the column as well, lessening A2001's chances of being trapped. And then the fire moved north, northwest and west, expanding the floor system to push the column 79, which you readily admit was at such time decoupled from A2001, south and then southeast and then east. It's the exact series of column movements that could cause A2001 to walk off the west side of its seat. (NIST even expressly notes that column 79 was being pushed to the east when walk off occurred in its model.)

Can you rule that out? No. Because you don't know where column 79 was relative to A2001 during these events, either in NIST's simulation or reality, and your terribly oversimplified girder expansion analyses doesn't even try to take its location into account at all.
More gobbledygook.
The only thing effecting the distance between column 79 and column 44 is the expansion of the slab. That is axiomatic.

However. I trying to answer you I noticed that I was not allowing for the expansion of the slab in my calculations.
Since the slab expands at about 85% of what the steel expands, it would take a temperature of about 360 °C for the west end of the flange of A2001 to become trapped (1/16 inch) behind the side plate of column 79. (see below)
But the east end of the A2001 flange is 1/2 too long to get by the side plate before it starts expanding.

A2001 - end of flange to column face (flange)

center line of bolt holes at center line of seat (and girder) to column face (flange)
A + B
5-13/16 + 6-3/16 = 12 divided by 2 = 6 inches

center line of bolt holes to end of girder 4-1/4 inches
center line at end of A2001 girder to face of column 79 - 1-3/4 inches

girder flange 11-1/2 inches wide divided by 2 = 5-3/4 inches
east end of girder flange 5-3/4 inches from girder center line
angle is 7/8:12 or 7/16 in 6 inches so:
1-3/4 – 7/16 = 1-5/16
east end of girder flange just over 1-5/16 inches from column face
conversely:
1-3/4 + 7/16 = 2-3/16
west end of girder flange just under 2-3/16 inches from column face

side plate protruded 13/16 beyond the face of column 79
"Column 79 at Floor 14 – W14x730 with two 26-in. x 2-in. side cover plates" NCSTAR 1-9, Vol. 2, p. 694 [PDF p. 356/760]
Side plates 26 inches - Column depth 22.4 inches
26 – 22.4 = 3.6 inches - divided by 2 =1.8 inches protruding on either side of the column

2.905 x .85 = 4.47 or 7/16 inch
2-3/16 - 7/16 = 1-12/16

#### Oystein

##### Senior Member
That is just an attempt to disregard the obvious by playing with semantics.
You are the one denying the obvious: That each connection failure (and floor slab failure) introduces a discontinuity to your imagined continuous paradise.

Incorrect. The only thing that would determined the distance between columns 79 and 44 is the concrete slab between them. That is axiomatic.
What utter nonsense! Boy have you painted yourself into a corner!

Other failures, expansions or contractions would have no effect on the distance between columns 79 and 44. You are just speculating with no data to support your assertion.
You just denied you need evidence because you raised your foregone conclusion to the status of "axiom". What data would you possibly accept?

Why don't you cut it short and make "WTC7 was explosive demolition" your axiom, and get it over with?

#### Oystein

##### Senior Member
...
The only thing effecting the distance between column 79 and column 44 is the expansion of the slab. That is axiomatic.
Please provide a textbook citation for this axiom, or admit you invented it because it is the only way you currently see to salvage your clearly untenable position!

Secondly, you keep forgetting the OTHER FLOOR SLABS! There are floors above and below f13 that experienced severe fires and thus expanded and contracted over time. Since the fires wandered not in unison, those floor slab deformations occurred differentially between floors.
You are not taking this into account, or you set as another, but unspoken, axiom that both columns would bend without limit, while the slab remains pristine and of (in effect) infinite compressive strength. What utter utter nonsense.

[more mathy numbers applied to model that assumes fires distorted nothing except that which you currently look at]
No one is interested in the six-legged dinosaur calculations.

#### Trailspotter

##### Senior Member.
Moderators, would it be possible to adjourn this discussion for one month or more? I have run out of popcorn

#### benthamitemetric

##### Senior Member
@Christopher 7, you are simply refusing to acknowledge the obvious and are not fooling anybody who is following this thread by trying to hand wave away my clearly presented arguments by calling them "gobbledygook ". If they were "gobbledygook," then you could demonstrate that by actually presenting arguments to refute them. But you can't.

Re your latest attempts to distract and deflect with your newfound "axiom" re magical concrete floors that control the entire building's response to massive fires, everything @Oystein said above is correct. I'll go further, however, and add that, even if this utterly preposterous assertion were true re how the concrete floors of a steel frame structure would behave in a fire (and, to be clear it's aboslutely not, but I'm just letting that go in arguendo), it still doesn't solve the most fundamental flaw in your analysis: while the concrete decks expanded in various way across all of the floors that were on fire, column 79 would have at all times been pushed by those expansions somewhere relative to A2001, which you have acknowledged decoupled from it and the concrete deck. And you don't know where that is. And, because you don't know where column 79 would have ended up relative to A2001 at any given point in time, you cannot say whether A2001 would have been trapped in its side plates at a time when it otherwise would have walked off its seat.

When you add to this line of argument the fact that the concrete decks were not in fact magical and, in reality, they and the various steel elements of the floors were being damaged by, and sometimes failing in, the fires, it's easy to understand why the movement of column 79 would have been even more complex still, depriving your simplified analysis any insight into the path of column 79 and where it would have ended up at any given point in time. The only reasonable way to determine that at even a very high level of approximation is with a fulsome simulation of the fire conditions and the affected structure's response thereto, which, incidentally, NIST and Weidlinger, but not Hulsey, undertook.

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#### Christopher 7

##### Active Member
The only thing effecting the distance between column 79 and column 44 is the expansion of the slab. That is axiomatic.
Please provide a textbook citation for this axiom, or admit you invented it because it is the only way you currently see to salvage your clearly untenable position!
That the floor slab between column 79 and 44 determines the distance between them is self evident.
That is a simple matter of physics. Your inability(?) to understand that is very telling.

#### Christopher 7

##### Active Member
while the concrete decks expanded in various way across all of the floors that were on fire, column 79 would have at all times been pushed by those expansions somewhere relative to A2001
The concrete floors only expanded a couple inches except for near the east exterior wall.
You are making an unsupported claim. Provide proof that slab expansion on other floors would change the distance between column 79 and 44 o the 13th floor or stop making that claim.
while the concrete decks expanded in various way across all of the floors that were on fire, column 79 would have at all times been pushed by those expansions somewhere relative to A2001
Your assumption that slab expansion of a couple inches on other floors could change the distance between columns 79 and 44 on floor 13 is unfounded and incorrect.
you cannot say whether A2001 would have been trapped in its side plates at a time when it otherwise would have walked off its seat.
A2001 would not have otherwise walked off of its seat. At 400 °C the floor beams would push A2001 3.3 inches.

#### Landru

##### Moderator
Staff member
This is starting an escalatory phase to impoliteness. Time out.

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