Lets see if we can lift this discussion out of squabbling over details.
The overall claim by Tony is that the NIST explanation of "Walk-off" is "wrong" or "impossible". Because it is Tony's claim which is currently under discussion it is his burden of proof to establish the validity of the claim. I will demonstrate in this post why Tony has so far not met his burden of proof.
Tony is challenging the formal findings of NIST delivered in response to imposed statutory obligations. Therefore the standard of proof which Tony must meet to satisfy his burden of proof is "beyond reasonable doubt". Both my claims as to "burden" and "standard" readily demonstrated if needed but let's get to the substance of the claim.
In essence the claim is that a technical finding by NIST is wrong. So Tony has two stages he must satisfy beyond reasonable doubt.
The first is identification and analysis of the technical issue subject of the claim viz "Walk-off of the girder spanning from Col79 to Col44". The second is what does he mean by "wrong" but defer that till we get the technical stuff out of the way.
Simply put the main flaw in Tony's claim is that he and most others responding to him have accepted a boundary around this technical question. Tony has assumed that the walk off was dominated by two factors viz thermal elongation/contraction of the subject girder and attached floor beams and sag of the same girder. And that the columns had neither moved nor suffered stress changes to cause them to move or "want" to move.
In effect both Tony and most responders have assumed that the distance between the columns has not altered due to fire OR that the columns have not experienced stress changes which could be loading the girder whilst the girder remains fastened in place. Obviously the two are related.
So I won't re-traverse those discussions which have taken place as to whether or not Tony is correct within the context of no change to the column connections. I intend to challenge the main implicit assumption which is that the end conditions of the girder attachment to the columns was not affected by heating due to fire. Put simply that the columns were still the same distance apart and would remain so once the girder attachments failed. IMO that is a fundamental false assumption.
AND Tony has not addressed the probability that the columns either had moved or had been subject to stresses towards movement but restrained by the girder whilst attached. So his claim is subject to "reasonable doubt" and not sustained.
There are two possible situations where Tony's implicit assumption would be correct. viz:
A) None of the other structural members of WTC7 surrounding col79, Col44, the girder and attached floor beams had been affected by temperature therefore only the subject beams had been affected therefore Tony's assumed setting is valid; OR
B) All or most of the relevant adjoining structural elements had been affected by temperature changes but all the resulting stress reallocations added up to zero impact on the end conditions of the girder.
Of those two "A)" is ridiculous and "B)" is ridiculously improbable.
So the challenge Tony:
Your burden of proof; the standard of proof "beyond reasonable doubt";
Can you demonstrate that either:
No members of the WTC7 frame adjacent to the col79, col44, girder and floor beams were affected by elevated temperatures which could cause stress re-distributions; (All the rest of the building around those columns stayed cool whilst the fires raged.) OR
That the temperature fluctuations imposed on that surrounding members caused stress re-distributions which cancelled out to zero?
Otherwise, Tony, I have established "reasonable doubt" and your claim fails.
Disclaimers:
1) I have limited my counter claim to the false context which Tony has assumed. I have not at this stage gone to the broader issues such as CD or not or Tony's limited objective of "Prove NIST wrong and get them to change."
2) I have not entered the discussion of technical issues within Tony's false context. Such matters being well handled by tfk and others.
3) I have not at this stage addressed nor needed to address what is Tony's standard for determining what constitutes "wrong". It is a more complex issue we can address if he meets the technical challenge.
