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

[gerrycan]

Both are plausible, among others, so they are not "opposites" at all. The NIST final report reckoned "rock off".

It's good that you're taking your work to YouTube. That's the right place for it.

Well, these are after all short videos intended for youtube, so i suppose i have to agree with you.

 

[plague311]

I'm asking which NIST explanation sounds like the most probable to have occurred. The point is that there is a choice.

So which is it that you believe, was it pushed off, or pulled off?

All I see is questions and requests for explanations that are disregarded. Do you have something you want to say?

 

[GlennB]

Well, these are after all short videos intended for youtube, so i suppose i have to agree with you.

But why ? If you have anything worth publishing then why put it among the weirdness and terminal banality of YouTube? Will there be dramatic music accompanying your videos?

What you're doing here is just so sad.

 

[pgimeno]

Yes, the rock off theory. Almost the opposite from their walk off theory.

Care to elaborate how it's "almost the opposite"?

 

[OCaptain]

I suppose you would have to define failure. NIST for example would appear to disagree with you, maybe their definition of failure is different to yours. Mine is too.

Despite not being an engineering professional, I'll take a stab at this one.

There is a difference between understanding a single point of failure for the initiation of the collapse (NIST), and misunderstanding that NIST's single point of failure means a single factor affecting column 79 and its connected girders (you). After the collapse moves beyond that column and girders, it's an increasingly complex affair that affects more columns, more girders, more floors.

Hopefully, the experts will correct me if I'm wrong.

 

[jaydeehess]

You forgot that we are talking about one floor and the column moving in relation to the girder. The floor beams and slab were being heated on the east side pushing west but the column could not move that way because of the continuous slab. NIST said the exterior wall did not move at all because that would take up some of the expansion.

This brings up an interesting point. Concrete expands about 85% as much as steel so when the beams had expanded 5" the slab would have expanded about 4 1/4". It couldn't move 250' of slab from column 79 to the other end of the building so it had to push the exterior wall out.

The slabs would not have expanded at the same rate (time) as the beams.

Yes that was what immediately sprang to mind when Chris posted that.
Yes I'll take your word for it that concrete expands at 85% that of steel once both steel and concrete are at the same temp, however the concrete simply will not heat up at the same rate as the steel allowing the steel beams to expand much faster than the concrete.

Another point would be to question what the steel column would do to concrete it is pressing against if it cannot move that concrete slab. Would it cause the exterior wall system tyo push out or would it spall and break pieces of the concrete.
Remember the concrete is hot, not through its entire volume as hot as the steel but certainly the surfaces of the concrete are hot and what does concrete do when hot? It is prone to spalling.

I would suppose that NIST did not take into account any lateral support from the slab simply because a thin floor slab cannot offer anything close to the same support that a steel girder can.

 

[gerrycan]

Care to elaborate how it's "almost the opposite"?

One is push only, the other i believe is push then pull.

 

[jaydeehess]

That makes sense to you?

Column 79 was surrounded by concrete slabs. It could not move laterally.

The fire was heating the slab on the east along with the girders so if column 79 could move it would move to the west - but there was this darn slab preventing that.

Did you just produce a reasoning to do away with beams and girders Chris?

Does that maker sense to you?

According to NIST the beams and girders were breaking shear studs bolts when they expanded but they said nothing about the columns moving laterally. They knew that the columns could not move laterally because they were surrounded by slabs. If you can't comprehend that then I don't know what else to say.

What I was getting at is that your absolutist statement would suggest that you consider the girders a waste of money in that they are not required to laterally support the columns, according to you.

In fact the beams and girders and columns form a system of support both for vertical and lateral loads. The columns REQUIRE sufficient lateral support in order to not buckle. Remove a major source of that lateral support and the column is in danger of buckling especially in long span floor systems where vertical loads are transferred to larger but fewer columns. instead of being distributed over many more smaller columns.

 

[pgimeno]

One is push only, the other i believe is push then pull.

Before or after the rocking?

 

[jaydeehess]

No, we are talking about the fact that the girder was NOT pushed off its seat because:
1) the seat was 12" wide not 11" wide and
2) the girder had stiffeners that would have prevented the bottom flange from folding and

You are able to show that the stiffeners would be sufficient to prevent this at the temperatures expected?

3) even if the beams could push the girder completely off the seat it would only drop 1" to the support plate.

To a support plate at the same temperatures that we expect the girder to be right? So you can show that the dynamic load of the girder dropping while it and the 2 inch wide support plate are at several hundred deg. would be insufficient to prevent girder failure?

 

[jaydeehess]

OK i tried that experiment you suggested. It burnt my hand you tricked me. But i do agree with you that steel conducts much better than concrete does. So why did NIST not let it conduct in their FEA model?

Wow, just came accross this gc. It is quite astounding that something can be explained to you as being insignificant and well within the range of the margin of error (steel conducts heat 200+ times faster than concrete subject to the same ambient temperature) and still return with the question "why did NIST not let it (the concrete)conduct in their FEA model?"

 

[ozeco41]

Despite not being an engineering professional, I'll take a stab at this one.

There is a difference between understanding a single point of failure for the initiation of the collapse (NIST), and misunderstanding that NIST's single point of failure means a single factor affecting column 79 and its connected girders (you). After the collapse moves beyond that column and girders, it's an increasingly complex affair that affects more columns, more girders, more floors.

Hopefully, the experts will correct me if I'm wrong.

You are heading in the right direction.

Certainly far closer than C7 or gerry are prepared to acknowledge. Whether they genuinely don't comprehend or are maintaining a false position for other reasons is still open to interpretation/revelation.

Given that massive fires were raging the idea that Col79 and Col44 would maintain their precise position whilst only the "girder" and those floor beams joined to it move under the effects of temperature is obviously ridiculous.

Exactly what bits moved how much and in what directions I won't try to predict.

 

[jaydeehess]

OK, before i go to sleep, what about an FEA competition to break the monotony. We can all guess what it stands for ok. I'll go first, and you lot can follow along.
Fool Everyday Americans....... Fast Enigmatic Animations.....Forget Every Actuality....... Freefall's Easy Actually....... you get the idea. Your turn, g'night.

aawwwww, when I read your first sentence there I had my hopes up that you or AE911T would actually be performing an FEA to refute NIST's.

You know, do research and determine parameters to input, equations to work on those parameters, justify it all, run the FEA and then examine the results..

But no, unfortunately all you, Chris, and AE911T want to do is snipe at NIST and put forth hand waving arguements about why NIST has to be wrong, call them liars and accessories to mass murder/in collusion to cover up mass murder, and never actually DO anything.

Geebus Kristoes, we have a debunker arranging for an analysis of the dust to refute Harrit et al. No government input at all in that one.
I would think that AE911T would have as a greater part of their membership, persons in the higher middle class earnings bracket who would be quite capable of contributing large enough sums to do at least a one FEA, say on the beams and girders in question here. Or if preferable one involving the building's response to the loss of that girder, you know, like what NIST did that showed collapse progressing to global collapse. Let me know when its going to be done and I'll send as much as I did for the dust analysis. (I am not in that higher earnings range though)

Just do it! (with apologies to Nike)

 

[triforcharity]

I can't quite picture Tri in a cheerleading outfit.

And it was once, and I had drank a 750ml of Crown Royal. Sue me.

 

[plague311]

aawwwww, when I read your first sentence there I had my hopes up that you or AE911T would actually be performing an FEA to refute NIST's.

You know, do research and determine parameters to input, equations to work on those parameters, justify it all, run the FEA and then examine the results..

But no, unfortunately all you, Chris, and AE911T want to do is snipe at NIST and put forth hand waving arguements about why NIST has to be wrong, call them liars and accessories to mass murder/in collusion to cover up mass murder, and never actually DO anything.

Geebus Kristoes, we have a debunker arranging for an analysis of the dust to refute Harrit et al. No government input at all in that one.
I would think that AE911T would have as a greater part of their membership, persons in the higher middle class earnings bracket who would be quite capable of contributing large enough sums to do at least a one FEA, say on the beams and girders in question here. Or if preferable one involving the building's response to the loss of that girder, you know, like what NIST did that showed collapse progressing to global collapse. Let me know when its going to be done and I'll send as much as I did for the dust analysis. (I am not in that higher earnings range though)

Just do it! (with apologies to Nike)

/agreed count me in for double what I donated on the dust analysis. It seems they have the software available already as well. Nothing stopping them other than, what I would assume, is laziness. I see nothing else blocking them from progressing.

 

[Jackanory]

Yes, the rock off theory. Almost the opposite from their walk off theory. So which is it that you believe, was it pushed off, or pulled off?

Which one would explosives or thermite choose? I know. Do you?

Would they have pushed it off or pulled it off?

Would they have pushed it up or pushed it down?

How much explosive was used and where?

Why was it silent?

Why no blast signatures? NONE AT ALL? LOOKY LIKEY....Not even close!

Why no fCD forensics? I am an ATO & BDO.....tell me.

Was it 12 wide"?

Was it 11" wide"?

Was it 8 1/4" wide?

Did the bolts shear?

Did welds fail?

Did floors contort?

Did the structure around it change, sag or shift?

Did the structure twist and contort on all sides?

Why are you focusing on one area? Is it because you need the infalable NIST? Is it because they where wrong or because you have nothing else but semantics?

Youtube rocks.

 

[slowsmile]

Well, these are after all short videos intended for youtube, so i suppose i have to agree with you.

So your target audience isn't professional engineers and similar - it's more like people on DIF - like the guy who linked to your video in the first place;

http://forum.davidicke.com/showthread.php?t=199667

lobuk - a crazy into Mayan Calendar garbage;

http://forum.davidicke.com/showpost.php?p=1059659476&postcount=8

and now he's posting on a thread saying that the Mexican earthquake was caused by HAARP.

http://forum.davidicke.com/showpost.php?p=1060705353&postcount=24

and you expect to get a new investigation?

 

[000063]

One is push only, the other i believe is push then pull.

Cough.

 

[tfk]

That makes sense to you?

Column 79 was surrounded by concrete slabs. It could not move laterally.

The fire was heating the slab on the east along with the girders so if column 79 could move it would move to the west - but there was this darn slab preventing that.

Oh really?

So much for your understanding of "what holds up what" in a building. Sorry, Chris, with beams & girders buckled or fallen underneath it, the concrete floors will not remain suspended in mid air.

And even before any beam or girder fell, the concrete was already fractured. First from the pullout of all the shear studs, and second from expansion from the fires, which first softened it, and then fractured it.

It'd help if you actually read what NIST explained.

Thermal Effects on Concrete Floors

Thermal expansion of concrete floors was restrained by the surrounding unheated slab sections, the interior and exterior columns, and shear studs at the floor beams and exterior spandrel beams. Restraint of thermal expansion led to compressive failure of the concrete slab through crushing, which softened the slab in tenant floor areas, and also led to loss of composite action with the floor beams. This failure mechanism usually occurred at slab surface locations where fires were burning, which led to much higher slab temperatures in a localized area.

Slab tensile failures were related to the response of floor beams and girders to thermal effects. When beams and girders failed at their connections, affected slab section cracked under tensile stresses where reverse curvature in the slab occurred over adjacent intact girders.

Fractured concrete ain't real good at resisting any sort of loads.

 

[Jackanory]

Oh really?

So much for your understanding of "what holds up what" in a building. Sorry, Chris, with beams & girders buckled or fallen underneath it, the concrete floors will not remain suspended in mid air.

And even before any beam or girder fell, the concrete was already fractured. First from the pullout of all the shear studs, and second from expansion from the fires, which first softened it, and then fractured it.

It'd help if you actually read what NIST explained.



Fractured concrete ain't real good at resisting any sort of loads.

Concrete doesn’t just crack and expand, it also audibly and visually ‘explodes’ in extreme heat. Not sure at what heat temps but I have attended quite a few IED clear up's to find smouldering wreckage etc and fires on concrete roads. These fires would give off secondary ‘blasts’ that from a distance we initially thought where secondary devices set for the BD teams. Infact, it was the direct heat from the fires being absorbed by the concrete and the concrete ‘exploding’ leaving a very distinctive crater. I should imagine that the concrete floors in all WTC’s reacted in a similar manner too.

Chris7 could try a simple experiment at home. Try burning some wood, office equipment etc on your concrete driveway......see what happens.