It looks like you're using an Ad Blocker.
Please white-list or disable AboveTopSecret.com in your ad-blocking tool.
Thank you.
Some features of ATS will be disabled while you continue to use an ad-blocker.
Originally posted by Griff
Yes, it would show that it is physically possible despite the already known tests of Cardington et al.
(btw, isn't that the going theory of the towers?).
Another thing is the thermodynamics involved. NIST states that the fire went approximately 20 minutes per cubicle and then moved on to the next. Thus only a cubicle's worth (and probably a few feet more taking the transition amounts on both ends into affect) would be burning at one time. NIST's computer model has the fires raging the entire time.
Last thing. I need more time. NIST had how many years/people/money to do this? It's going to take one person without as many resources a lot longer to achieve what you want.
Also, the original structural documentation would be hepful. But, I will say thank you for the link to the latest paper you gave me. I read in the NIST report about that paper, but I didn't have it.
I'm not sure what you mean here.
Could you paraphrase which parts please? Thanks.
Originally posted by exponent
The exterior column buckling as mentioned above would not be achievable due to a reduction in lateral support. Gravity loads on unbraced columns would (according to a Structural Engineer at JREF) not result in severe deflections, but there are pictures of these deflections increasing over time in the report.
Originally posted by Griff
I'm asking how beam buckling, beam buckling, beam buckling causes this collapse. I agree that removing some floors worth of horizontal bracing would cause column buckling, column buckling, column buckling. Notice the difference between beam and column?
Originally posted by Seymour Butz
But if floor beams "grew" enough to cause the girder, which was, to shear its bolts or tear out of the flange, I could see how it would, by the way described above, above, above. The NISt report goes into tjis in some detail, but I skipped over that part. (my bad)
Clarification: Would the girder buckle down, or would it be displaced laterally by the "pushing" floor beams?
Why would a buckle in either direction NOT result in the connection failing?
Originally posted by Griff
1-Displaced laterally. But, remember, there are also beams pushing from the opposite side of the girder that need to be taken into account that are obtaining their sability from girders and beams beyond.
2-Why would a connection failing cause all the others to fail and result in a floor cascading down to the next causing that floor and multiple others to fail?
Originally posted by exponent
No, two seconds after the main collapse portion starts, and that was just an estimate. This occurs at least 10 seconds into their analysis.
Why couldn't they verify the building's construction. I saw Griff paste this and haven't properly contested it yet, but I'll be surprised if you get the reason right
Originally posted by tezzajw
It took the building less than ten seconds to collapse, so how can the collapse sequence last longer than that?
So, two seconds is just an estimate? What can NIST actually claim that is accurate?
I don't need a reason why they can't verify it. The fact is that NIST state they can't verify the building's design or construction. Read Disclaimer 4 on page 4/115.
due to the destruction of the WTC buildings, NIST could not verify the actual (or as-built) construction
Originally posted by cashlink
(I really don't think you can blame NIST for being unable to walk around a destroyed building.)
Are you implying they did not have the blue prints for the building?
Originally posted by exponent
It was my estimate, NIST doesn't consider accuracy anywhere after the global collapse phase starts I don't think.
Perhaps you should read their reason, instead of simply parroting claims you have heard elsewhere.
Originally posted by Griff
1-So, are you saying that the girder/column connection would fail before the girder?
2-BTW, that's a pretty dumb design (if true) if you ask me. There should always be bracing against lateral-torsional buckling. Imagine standing on a long 2x12 board. The board will tend to rotate (lateral-torsional buckling) if not braced at certain points. Now, imagine just bracing it on one side. The other will still be susceptible to rotation. An interesting point you bring up none-the-less.
Originally posted by tezzajw
So without considering accuracy, who knows how well the NIST model fits what happened?
Perhaps you should read Disclaimer 4 on page 4/115 of the report where NIST states that it can't verify the design or construction.
Originally posted by cashlink
Ok, so if they have the blueprints why couldn’t NIST verify the construction?
Am I to assume then, that blueprints do not tell you how to build a building?
Originally posted by exponent
Anyone who reads the NIST report?
Originally posted by exponent
I really don't think you can blame NIST for being unable to walk around a destroyed building.
Originally posted by Seymour Butz
2- page 58/404 1-9 Vol 1 has it. I remembered a little wrong. There's ONE floor beam bracing it, but it's virtually parallel to the girder, maybe a 25 degree angle at best, rather than perpendicular, so I wouldn't think it would give much bracing.