'What about building 7'?

[pgimeno]

Well, I think that that settles the question of whether NIST needed to consider the stiffeners when estimating the walk-off distance: the girder would fail anyway once its CoG was off the seat, regardless of the stiffeners. NIST probably knew that and didn't need to consider the stiffeners. Omitting them was a reasonable simplification of the simulation.

The column (and thus the seat) displacing to the east settles the question of whether the beams expanded by the length of the walk-off: they didn't need to, because the displacement of the seat added to the total distance for walk-off. And that distance was large enough for breaking connections in three other floors.

The expansion of the beams before the girder settles the question of why the girder wasn't trapped between the plates.

So far nothing changes in NIST's analysis even when all these factors are considered.

So, the only issue remaining from gerrycan's list is the beam stubs. What about them, gerry?

 

[Spanx]

No, it doesn't. "Frankel 1985" is a reference. It's listed in the REFERENCES section. All the other drawings figures contain the same text "Frankel 1985".

Let me repeat the post that you must have missed:

_____________________________



And you surely can support that claim, right?

While you get on it, let me paste you some quotes and the REFERENCES section in NCSTAR 1-9 Chapter 2 p.15.

The quotes:

The structural design drawings (Cantor 1985) specified design forces for connections and suggested a typical detail, but did not show specific connection designs; this was standard practice on the U.S. east coast. The erection drawings (Frankel 1985) indicated that design shear forces for the typical beam and girder connections were to be taken from the American Institute of Steel Construction (AISC) beam design tables for beams without shear studs, using 1.5 times those forces for beams with shear studs. The fabrication shop drawings (Frankel 1985a) were used to confirm information about floor connections, which NIST obtained from the structural and erection drawings and from photographs taken during renovations conducted during 1989 to 1990 on a number of floors. [...]
​

And the references (p.45):

2.7 REFERENCES
[...]
Cantor 1985. Irwin G. Cantor P.C., Structural Engineers, Structural Drawings, 7 World Trade Center.

Cantor 1988. Irwin G. Cantor P.C., Structural Engineers, Structural Drawings for Salomon Brothers 7
 World Trade Center Headquarters.

Frankel 1985. Frankel Steel Limited, Erection Drawings, 7 World Trade Center.

Frankel 1985a. Frankel Steel Limited, Fabrication Shop Drawings, 7 World Trade Center (drawing set was not sealed).
​

And in page 359-360:

8.11 REFERENCES

[...]
Frankel 1985. Frankel Steel Limited, Erection Drawings, 7 World Trade Center.

Frankel 1985a. Frankel Steel Limited, Fabrication Shop Drawings, 7 World Trade Center (drawing set was not sealed).
​

Are they talking about the same thing? Let's see the captions of some figures.

[qimg]http://www.formauri.es/personal/pgimeno/xfiles/11-s/Frankel-1985-collage.jpg[/qimg]

Whatever the correct drawing number is, it must contain a hell of a lot of information!



Oh Gerry, Gerry... Why don't you listen when I tell you to drop that strategy?

Seriously, stop with the ad-hom. It backfires on you every time.

I don't think this was addressed by gerry

 

[Porkpie Hat]

Web buckling, that's interesting. I guess you mean something like this:

[qimg]http://www.formauri.es/personal/pgimeno/xfiles/11-s/web-buckle.png[/qimg]

I previously thought that the top flange would yield first, like this.

[qimg]http://www.formauri.es/personal/pgimeno/xfiles/11-s/flange-yield.png[/qimg]

(not to scale, angle exaggerated for clarity)

Wouldn't the stiffener extend from flange to flange?

 

[Animal]

Wouldn't the stiffener extend from flange to flange?

Per the drawings they did not.

 

[Animal]

Well, I think that that settles the question of whether NIST needed to consider the stiffeners when estimating the walk-off distance: the girder would fail anyway once its CoG was off the seat, regardless of the stiffeners. NIST probably knew that and didn't need to consider the stiffeners. Omitting them was a reasonable simplification of the simulation.

Exactly......and no troofer has ever been able to explain why......if NIST was being nefarious.......why they would add a seat stiffener to make it HARDER for the connection to fail.

 

[Porkpie Hat]

Per the drawings they did not.

Just find that odd. I've been fabricating oil and gas equipment for about thirty years and have never seen that before (and the vast majority of structures I've built have been statically loaded).

Given that it's not hard to see either buckling scenario (web or flange) occurring depending on distribution of heat.

 

[Porkpie Hat]

Per the drawings they did not.

Exactly......and no troofer has ever been able to explain why......if NIST was being nefarious.......why they would add a seat stiffener to make it HARDER for the connection to fail.

My guess would be that they somehow have to justify their weak position by overlooking the obvious in favour of their fantasy.

The reality is that there's no way of knowing the exact sequence of events, including the dimensional changes which ocurred due to heating and cooling phases and local failures, which lead to global collapse.

I've been heat straightening steel structures for decades and know for a fact that you can't expect one member to react in isolation to everything connected to it.

 

[Animal]

My guess would be that they somehow have to justify their weak position by overlooking the obvious in favour of their fantasy.

The reality is that there's no way of knowing the exact sequence of events, including the dimensional changes which ocurred due to heating and cooling phases and local failures, which lead to global collapse.

I've been heat straightening steel structures for decades and know for a fact that you can't expect one member to react in isolation to everything connected to it.

I agree. I think the NIST took the approach of finding the hardest way to fail (the walk off) while balancing that with the amount of computer computation time required. Any number of ways the girder could have failed would start the chain reaction of failure. Troofers have nothing so they resort to nit picks to keep the faithful in line and the donations flowing so dicky gage can continue is all expense paid vacations.

 

[JayUtah]

Wouldn't the stiffener extend from flange to flange?

Web stiffeners in general do not need to, and in a few cases are not even attached to either flange. When it is done this way, it's because it's easier to cut and fit them if you don't have to worry about sniping or coping them to accommodate the web-flange joint, which often has a fillet or a weld that varies in shape. In a coped design, it's often hard to get paint or sealant or insulation into the cope holes, so you just avoid the flange connection altogether. It still functions suitably as a web stiffener.

Bearing stiffeners attach to the bottom flange and can rise to the top flange but do not have to be connected (or connected well) to the top. The web-stiffening role is suitably satisfied by shortening the otherwise unstiffened height of the web and reducing its tendency to buckle under axial load. The load path in the bearing-stiffener role varies. Under symmetrical bearing reaction, the stiffener applies the highest load at the foot of the web, with the load dropping off the higher up the stiffener you go. So you can save time and metal by leaving off the top portion of the stiffener -- the part that would bear less of the load anyway. It's the same reason that for footed stiffeners, the feet are typically triangular.

 

[JayUtah]

Just find that odd. I've been fabricating oil and gas equipment for about thirty years and have never seen that before (and the vast majority of structures I've built have been statically loaded).

Here's an old-school example using riveted stiffeners, i.e., riveted only to the web. I imagine they abut the flanges, but that abutment is not necessary for them to function.

http://static.panoramio.com/photos/large/37780698.jpg

You see the concrete pier and the sole plate assembly between the pier and the girder. The bearing stiffener is just above the sole. The two flanking stiffeners are jack points, for when they have to replace the sole. Then you typically need one every time the flange changes direction; compressive stress concentrates at those points in the web and could tend to buckle it. The evenly-spaced ones are probably just for shear stress.

Given that it's not hard to see either buckling scenario (web or flange) occurring depending on distribution of heat.

The key factor in the failure is the eccentric load applied to the girder foot. Truthers err when they claim the stiffener pattern would work asymmetrically to preserve the connection.

 

[NoahFence]

Is it at all possible that the NIST report simplified this or that because for its intended audience, some things would be just understood?

This is probably why MM and that group are having such a hard time with this.

 

[Animal]

Truthers err .

You could have shortened it to this

 

[JayUtah]

Is it at all possible that the NIST report simplified this or that because for its intended audience, some things would be just understood?

Yes, I think it's not only possible but likely. By convention and sometimes by law, reports by investigative agencies must be offered to the public. That doesn't mean they must be written in layman's terms. It is not NIST's responsibility to educate all readers in the sciences, methods, and practices they use which are common to the relevant sciences and industries. That doesn't mean they shouldn't thoroughly describe their methods, but it does mean they can allude to common practice where those methods are unremarkable, without having to elaborate.

Omitting the bearing stiffener while investigating walk-off would not be remarkable, since the stiffener helps only in a properly seated connection. Walk-off all but presumes an improperly-seated connection, and the straw-man failure mode Truthers propose is not a thing. Adding the seat stiffener that wasn't in the design was exceptionally important to investigating walk-off because that's the only way to isolate that particular failure mode in the model. It's the physical equivalent to controlling for a variable in a scientific study.

This is probably why MM and that group are having such a hard time with this.

Possibly, but "having trouble" suggests that these are innocent mistakes. While some Truthers may simply not have the background in engineering to appreciate NIST's approach, and may simply be misunderstanding what others say, I think other Truthers are deliberately misrepresenting the underlying principles and methods, and their grasp of them, to generate a convincing-sounding impression that NIST has committed "critical" errors.

 

[jaydeehess]

[
The main fall back argument for official story supporters is the; "sure an engineered implosion fits what was observed but I watched it on TV and I never heard any explosions."

While the recorded video was generally good, most of the audio recordings from around the World Trade Center on 9/11, were poor, too directional, too local, or too distorted.

While the viewers heard nothing, reporters at the scene, were observed to dramatically turn and react to loud explosive sounds that were never recorded by the microphones they had been speaking into moments earlier.

Many eyewitnesses reported hearing explosions where microphones did not.

The NIST realized that an engineered implosion explained what happened to 7WTC, but they dismissed this hypothesis because they assumed there would be high, easily recorded sound levels.

Of course the NIST looked at the recordings of other building demolitions. Those recorded events that were planned and publicized in advance and not staged in secrecy. Buildings openly prepped, with windows pre-broken and floors cleared of furnishings, allowing for excellent sound echo and projection (ever notice how quiet it is inside an office tower behind those heavy sealed windows?)

In defiance of the NIST's thinking, we have the glaring fact that for the most part, the biggest noises of the day, were not even recorded well, for it is not easy to obtain clean, broad, audio recordings outside of a sound stage unless you have engineered for it.

We know with certainty that cameras recorded the planes impacting both the WTC Twin Towers, the subsequent fireball explosions, the falling debris, the collapses of the Twin Towers, and finally the collapse of 7WTC at 5:20 pm on 9/11.

With all of those recordings, what was most memorable, was the video, and what was the least memorable, or non-existent, was the sound.

And we are not talking traffic noise, we are talking about the gigantic sound signatures of two 110 storey and one 47 storey steel-structured office towers collapsing at high speed.

,,,and yet in those well set up videos of true demolitions what's missing so many times? The sound of the actual collapse. What you do hear is the explosions.

Watch a TV show or a movie that has a less than pristine images and poor quality audio, and I can tell you as a veteran editor of broadcast TV that the viewer is going to be more bothered by the absent sound quality.

Yes, what's your point? That the videos are poor?

 

[DGM]

The NIST realized that an engineered implosion explained what happened to 7WTC, but they dismissed this hypothesis because they assumed there would be high, easily recorded sound levels.

Actually, they also found no evidence of any kind to support an engineered implosion. Did you forget this?

Oddly enough, you have none also........

 

[slowsmile]

While the recorded video was generally good, most of the audio recordings from around the World Trade Center on 9/11, were poor, too directional, too local, or too distorted.

While the viewers heard nothing, reporters at the scene, were observed to dramatically turn and react to loud explosive sounds that were never recorded by the microphones they had been speaking into moments earlier.

Many eyewitnesses reported hearing explosions where microphones did not.

So it wasn't "Hush a Boom" explosives, it was "Ignore a Boom" microphones

 

[Dog Town]

...

Still tilting at windmills, I see! Sad really.

 

[beachnut]

... Many eyewitnesses reported hearing explosions where microphones did not. ...

That solves 911, you have witnesses who heard explosions; did you tell gerrycan? He needs help with his indirect method of attacking NIST probable cause so he can recruit more followers for the CD fantasy.

Wait, did the witnesses hear explosives? Darn you said explosions, not explosives. Never mind

 

[LSSBB]

So it wasn't "Hush a Boom" explosives, it was "Ignore a Boom" microphones

Funny thing is, knowing explosives sound levels, distances, intervening materials, and the characteristics of recording devices, calculations can be made and experiments performed to try to establish support for MM's reasoning for the lack of sound. MM does not perform any of this work, he just makes a statement of belief and expects his audience to accept it.

 

[Spanx]

Funny thing is, knowing explosives sound levels, distances, intervening materials, and the characteristics of recording devices, calculations can be made and experiments performed to try to establish support for MM's reasoning for the lack of sound. MM does not perform any of this work, he just makes a statement of belief and expects his audience to accept it.

Hang on a minute, MM has done loads of research don't you know he has his own miragememories youtube channel. My favourite is the sounds of explosions before the collapse of wtc7

It's good enough for MM and good enough for Gerry. This is all that is needed if you have woken up