WTC7 and the girder walk-off between column 79 and 44

[GlennB]

What part of "omitted" don't you understand?

Early on, here (actually much earlier than that, iirc, I'll look) you posted drawing 9114. It includes the stiffener on the top flange (I presume there cannot have been one on the bottom flange, as it would have raised the girder above the plate on a 3/4" strip of steel and therefore not flush with the plate).

So, 9114 doesn't omit the stiffener in the plan view, and surely this has been your point throughout?

My question was why it isn't included in 9114 in the elevation view.

 

[Christopher7]

Early on, here (actually much earlier than that, iirc, I'll look) you posted drawing 9114. It includes the stiffeners on the top flange

Wrong. It shows the top view of the stiffeners on the bottom flange. In the next post I talk about the stiffeners on the bottom flange. Here is the side view. Had you bothered to do the research you would not be confused.

This is a subject shift/derail. NIST omitted the stiffeners in their final report and that is fraud.
The stiffeners are there to prevent the flange from folding. They were omitted because the girder would not fail when the center line of the girder was pushed beyond the seat. NIST also lied about the width of the seat to get their walk-off. It didn't happen.

 

[Newtons Bit]

The existence of the web stiffeners is actually a somewhat valid criticism. They will stiffen the flange from bending. However, the beam will still roll off once the web has been pushed off the seat.

 

[GlennB]

The existence of the web stiffeners is actually a somewhat valid criticism. They will stiffen the flange from bending. However, the beam will still roll off once the web has been pushed off the seat.

As a matter of interest, why would there be web stiffeners on the seated and bolted endmost part of the girder? What rotational force would tend to make the flange 'fold' such that it would need stiffening? And presumably it would be triangular in section as it only extends ~half-way up the web?

Just curious.

 

[000063]

More pressure means more range. The material blown from the front of the LSC has a significantly greater range than the omnidirectional components.

Sword of Truth did try to say they were equal.

My point is that the directional charge pressure reaching the windows about 50 feet away with enough pressure remaining to break them does not imply the omnidirectional components would, as they are at a much lower pressure to start with.

I love how you ignore the parts of my posts repeatedly pointing out your lack of evidence, in order to make an assertion without evidence. And one I already specifically pointed out you didn't back up.

http://www.internationalskeptics.com/forums/showthread.php?postid=8337772#post8337772
http://www.internationalskeptics.com/forums/showthread.php?postid=8337806#post8337806

You're also backpedaling from "the rest of the blast wouldn't break the windows" to "the rest of the blast has not been proven to be enough to break the windows".

I noticed that everyone here ignored the indisputable proof that NIST committed [at least] two frauds to make their walk-off work.

1) NIST said the seat was 11" wide but the plans clearly show it was 1' 0"

2) NIST omitted the stiffeners, clearly shown on the plans.

These are not "innocent" mistakes.

Saying it's "indisputable proof" doesn't actually make it so. You have never been able to provide any evidence whatsoever of ill intent, as opposed to the much more likely "error".

 

[Newtons Bit]

As a matter of interest, why would there be web stiffeners on the seated and bolted endmost part of the girder? What rotational force would tend to make the flange 'fold' such that it would need stiffening? And presumably it would be triangular in section as it only extends ~half-way up the web?

Just curious.

The web stiffeners are there to prevent the web from buckling at the bearing seat. The web is relatively tall and very large amount of load is transferred from the web to the seat over a short distance. This tends to cause local buckling in the thin web. AISC has a number of equations that define such phenomenon.

 

[GlennB]

The web stiffeners are there to prevent the web from buckling at the bearing seat. The web is relatively tall and very large amount of load is transferred from the web to the seat over a short distance. This tends to cause local buckling in the thin web. AISC has a number of equations that define such phenomenon.

Apologies, I meant to ask about flange stiffeners not web stiffeners. The web stiffeners I've noticed while reading around this subject are the full height of the web. The item in drawing 9114 is only about half the height of the web. Perhaps this is routine though.

 

[Newtons Bit]

Apologies, I meant to ask about flange stiffeners not web stiffeners. The web stiffeners I've noticed while reading around this subject are the full height of the web. The item in drawing 9114 is only about half the height of the web. Perhaps this is routine though.

The item in 9114 is a web stiffener. It's common for these to not be full-height. I think there's some confusion going around due to people who don't normally work in steel trying to talk what's labeled in shop drawings.

 

[Christopher7]

The existence of the web stiffeners is actually a somewhat valid criticism.

Somewhat? Omitting the stiffeners is fraud. Lying about the width of the seat is fraud.

They will stiffen the flange from bending. However, the beam will still roll off once the web has been pushed off the seat.

IYO. Even if you are right, that is not the NIST hypothesis.

Since the seat was 1' 0", the girder would have to be pushed at least 6", not the 5.5" NIST says. Furthermore, The NIST hypothesis requires the flange to fold which it would not because of the stiffeners as you have acknowledged.

"Therefore, when the web was no longer supported by the bearing seat, the beam was assumed to have lost support, as the flexural stiffness of the bottom flange was assumed to be insufficient for transferring the gravity loads. Under such conditions, the beam would fall to the floor below under its self weight." NCSTAR 1-9 Vol.2 pg 488 [pdf pg 150]

 

[Christopher7]

The item in 9114 is a web stiffener. It's common for these to not be full-height. I think there's some confusion going around due to people who don't normally work in steel trying to talk what's labeled in shop drawings.

You are the one who doesn't understand what the stiffeners are for. Even if they are for stiffening the web, they obviously stiffen the bottom flange and omitting them to get the walk-off to work is fraud.

 

[Tony Szamboti]

The item in 9114 is a web stiffener. It's common for these to not be full-height. I think there's some confusion going around due to people who don't normally work in steel trying to talk what's labeled in shop drawings.

This paper discusses both flange and web stiffeners http://scholar.lib.vt.edu/theses/available/etd-100599-150238/unrestricted/chapter1.pdf

It seems they are always half height for the flange and can be for web stiffeners also. Concerning web stiffeners it says

Full depth stiffeners are required for cases where applied compressive forces exceed the applicable column limit states. Half depth stiffeners may be used for the other cases.

But as you say, even if the intent was for buttressing the web it will also stiffen the flange and prevent it from bending with the web off the seat.

I don't understand your basis for saying the girder would roll off if the web was off the seat. There would be a torque applied but that should be more than offset by the beam connections.

 

[Tony Szamboti]

Somewhat? Omitting the stiffeners is fraud. Lying about the width of the seat is fraud.

IYO. Even if you are right, that is not the NIST hypothesis.

Since the seat was 1' 0", the girder would have to be pushed at least 6", not the 5.5" NIST says. Furthermore, The NIST hypothesis requires the flange to fold which it would not because of the stiffeners as you have acknowledged.

"Therefore, when the web was no longer supported by the bearing seat, the beam was assumed to have lost support, as the flexural stiffness of the bottom flange was assumed to be insufficient for transferring the gravity loads. Under such conditions, the beam would fall to the floor below under its self weight." NCSTAR 1-9 Vol.2 pg 488 [pdf pg 150]

Since the web was 0.580" thick and the girder was initially centered on the seat, for the web to be fully off the seat would require a horizontal translation of the girder of

half the seat width + half the web thickness = 6.00 + 0.29 = 6.29"

and at that point the girder support would be fully dependent on the flange and the stiffener.

 

[carlitos]

Because of course, everything remained in exactly its "as built" dimensions while it sat on freaking fire for 6 hours, creaking and leaning. That's why engineers like Mr. Szamboti can measure things to three decimal places.

Just some advice on marketing your lies - It's not very convincing to this non-engineer. Maybe you should put your techno-babble on less cerebral sites, like youtube comments. Does Gage give you a cut, or do you do this for the lulz?

 

[Newtons Bit]

You are the one who doesn't understand what the stiffeners are for. Even if they are for stiffening the web, they obviously stiffen the bottom flange and omitting them to get the walk-off to work is fraud.

The existence of the web stiffeners is actually a somewhat valid criticism. They will stiffen the flange from bending. However, the beam will still roll off once the web has been pushed off the seat.

 

[Tony Szamboti]

Because of course, everything remained in exactly its "as built" dimensions while it sat on freaking fire for 6 hours, creaking and leaning. That's why engineers like Mr. Szamboti can measure things to three decimal places.

Just some advice on marketing your lies - It's not very convincing to this non-engineer. Maybe you should put your techno-babble on less cerebral sites, like youtube comments. Does Gage give you a cut, or do you do this for the lulz?

It doesn't need to be convincing to anyone who throws up their hands and says things like "the building was on fire for 6 hours, creaking and leaning", implying that there is no way we can determine if the girder could be pushed off its seat or not, but offering no tangible mechanisms as to why.

What is actually mind numbingly hilarious is, that after making comments like that, you then tell me to go to less cerebral sites.

 

[Christopher7]

Because of course, everything remained in exactly its "as built" dimensions while it sat on freaking fire for 6 hours, creaking and leaning. That's why engineers like Mr. Szamboti can measure things to three decimal places.

Calculating the expansion or sag is not exact and three decimal places are not necessary [but normal for engineers]. But that in no way invalidates gerrycan's and Tony's calculations.

The point is valid. At 600^oC, a steel beam loses half of its strength and starts to sag. You don't have to be an engineer to understand that. The question is how much. The calculations by jerrycan and Tony give a reasonably accurate estimate of the expansion and sag.

 

[carlitos]

It doesn't need to be convincing to a non-engineer like you who throws up his hands and says things like "the building was on fire for 6 hours, creaking and leaning", implying that has to be the reason it fell, no matter what other observations there were, like a fully symmetric collapse of the exterior.
What is actually mind numbingly hilarious is the fact that you then have the gall, after making comments like that, to tell me to go to less cerebral sites.

The highlighted bit is a lie.

 

[Tony Szamboti]

The highlighted bit is a lie.

The entire exterior came down even with the horizon. And you want to say it is lying to call that symmetric?

 

[Christopher7]

The highlighted bit is a lie.

Typical denier insult based on semantics. This just shows your desire to find fault.

 

[Tony Szamboti]

Typical denier insult based on semantics. This just shows your desire to find fault.

Unfortunately, I think it is sour grapes starting to show with certain individuals. This argument is over, in the sense that it has been clearly shown that the NIST collapse initiation mechanism for WTC 7 is not viable.