DGM
Skeptic not Atheist
WTC7 and the girder walk-off between column 79 and 44
- Thread starter Gamolon
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ozeco41
Philosopher
Who cares what NIST said???
Your interpretation is what supports your claim.
And your idea that the beams attached to the girder could expand due to temperature BUT the girder wouldn't.....
...well let's say there is room for your thinking to improve.
Still thinking "one isolated factor" I see.
Not at all, the reason that we never took into account the expansion of the girder is that if it was left hard up to the column face (which it would have been) this goes against NISTs walk off theory. These videos have deliberatley moved the variables in favour of nist. However, having expanded and went into compression between 79 and 44, there is a need for a different explanation, and so now we have the rock off theory. Which one do you think happened, walk of rock?
slowsmile
Critical Thinker
That's a press conference you're linking to - papers please.
Who put "Column 79" there and on what basis?
This is a structural drawing taken from the FOIA release. You would be best downloading them and going to drawing 9114 and looking at it for yourself. What is it that you think is being misrepresented exactly? Maybe i could help clear this up for you.
Is the red text also in the NIST release? I can't find it.
What floor does that drawing correspond to?
What girder is that?
The red text has been added. Its astounding that people here are willling to argue these points at all without having first studied these drawings. I suggest you go look at them then make your point. Are you genuinley unsure whether this is column 79 or not? I am 100% sure that it is.
Yes. What floor does that drawing correspond to?
Look at the drawing, the sideplates being 1,2, or 3", as marked on the drawing should tell you what floors this relates to. The column schedule will be useful to you in this aswell. I dont have time to upload them all for you just now, but as i have already said, we are willing to speak to you realtime about this issue, and perhaps clear up some of the questions that you have. Failing that, I suggest you study the drawings for yourself.
What's wrong with the concept of a displaced girder with just 0.5" support rocking off the seat?
Your premise is wrong, as is NISTs. And who said that the girder only had 0.5" support and where did they say that?
triforcharity
Banned
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No, you don't. You've missed quite a few posts in this thread. But, you'll ignore them.
Perhaps you could help your friends with the drawings here. If you let me know when you are free i will happily take the time talk to you about this.
You say the seat is 12" wide so the girder had to be displaced 6" to be unsupported. NIST claims 5.5" was enough to get it off the seat. Actually you calculate 5.7" which leaves only 0.3" support.
My premise is not wrong. Rocking is a plausible possibility.
Originally Posted by pgimeno
" What's wrong with the concept of a displaced girder with just 0.5" support rocking off the seat? "
Hang on, the girder originally has 12" support from plate 'pf'. It hypothetically moves 5.7" (which wouldnt happen, as explained in the videos) How much support does that leave the girder with?
Gravity shear loads in a beam were transferred to the bearing seat primarily in the proximity of the web on the bottom flange. 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.
NCSTAR 1-9 p.488, "Criteria to Remove Locally Unstable Members Due to Loss of Vertical Support"
What are your reasons to contend that?
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The stiffner plates on each side of the girder web, and the fact that even if the web had moved the maximum amount (which it couldnt) it would still be supported by the seat 'pf' . You wont find the stiffner plates in NISTs report though, you have to go to the drawings to see them.
My original problem was with you saying that 'What's wrong with the concept of a displaced girder with just 0.5" support rocking off the seat?' , which i presume you now retract.
we? i dont understand why this is funny.
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