I have made my point on the ambiguity, which is there whether you acknowledge it or not.Pgimeno, you are trying to obfuscate a very simple thing which is very clearly stated by NIST in chapter 11/page 488. It gives two possible modes of walk off failure:
1) by axial movement 2) by lateral movement.
No matter how much you try to confuse the issue, it is comletely obvious that the axial/straight forward or backwards movement of a beam or a girder will not push it to the side and leave it resting on only one side; only the second choice, the lateral/sideways movement, will leave a beam or girder resting on only one side/that one flange on that side.
And page 488 goes on to explain that the failure mode of option 2, the lateral walk off, is by the lack of flexural stiffness of that one flange.
There is absolutely no ambiguity here unless someone tries to create it by quoting selected parts out of context.
The only question is whether or not the walk off scenario at the 44-79 girder is by 1) axial displacement or 2) lateral displacement.
And again, NIST very clearly answers this question in chapter 11/page 525:
"The bearing seat at Column 79 was 11 in. (revised to 12) wide. Thus, when the girder end at Column 79 had been pushed laterally at least 5.5 in (revised to 6.25), it was no longer supported by the bearing seat."
Chapter 11 therefore concludes that the girder en at column 79 walked off the seat once the girder had somehow been displaced sideways/laterally 6.25 inches, at which point it was only resting on that one bottom flange on one side of the girder, which consequently folds due to lack of "flexural stiffness".
But regardless of which interpretation NIST actually meant that applied to the girders, that's just a side question on the precision of that paragraph, and matters little to whether the analysis is correct or not. What matters is whether the stiffeners would have made a significant difference. Thus the question that I told gerrycan he needed to find the answer for:
Is it reasonable to consider a girder failed when its web is off its seat, even if there are web stiffener plates welded to the bottom flange?
No one needs to. As has been proven in this thread, the flaws that "truthers" claim to have found are all based on false premises. Since those criticisms do not hold any water from an engineering standpoint, the report stands on its own.I just want to see if anyone here can actually justify NIST´s walk off theory with actual data and numbers.
Now please either prove or retract this accusation:
I have read what they replied to Cole, and they don't say the part I've highlighted. Can you provide the citation where they said it would not have any strengthening effect? Or are you making up words that NIST never said?
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