No, I'm simply pointing out that you're being overly dogmatic about insisting that these are sequential and that no parts of them can be simultaneous.
No, I've clearly stated there is no reason why events cannot overlap. I do, however, make the point that sequential events within a process definition must be separated by finite amounts of time.
Each of these is a process, and there is no reason to expect that any one process had progressed to completion before any other process commenced.
Of course. Why are you stuck on this point ? I've stated several times, and again just above, that there's no reason why processes cannot overlap. Indeed each *event* discussed is of course made-up of an almost infinite number of smaller discrete events, beginning and ending at various points in time.
Each failure occurs at a point where deformation exceeds the elastic limit.
Event and process dependant. Elastic limit of most perimeter panels was not exceeded, as they did not buckle.
Prior to that point, deformations can still occur; in fact, they must.
Please be more specific. Deformation of what ? I agree that all deformation has a global effect, though it may be negligibly small.
Working out which deformations will reach the failure point first, in a scenario where the entire structure is deforming with different parts deforming in different ways, is an extremely complicated thing to do, and won't be achieved by laymen arguing on a discussion forum.
Not entirely true Dave. It's really not too difficult to, say, determine a timing between any suggested south face failure and subsequent north face failure. As I said, and included visual cueing for, we can SEE the south to north progression occur over a finite eriod of time.
Care to suggest a timing ?
It needs the sort of analytical tools available to NIST, and not (currently) to you or me.
I don't agree. The simple GIF provided above contains useful information. LS-Dyna is in the building also.
But it should be obvious that all these events are occurring at the same time.
South face failure and north face failure are not, for a start.
For any one part of the structure to fail, deformations must be taking place to the remainder of the structure; it's a geometrical necessity.
There's no problem going into more detail, and sure (for many situations tho not all), however, it's clear that any suggestion that south and north perimeter failed simultaneously is nonsense.
As the perimeter columns start to bow inwards, the distance between their endpoints is reduced, so the length of one face of the tower is shorter than that of the opposite face. This must result in deformations in the rest of the structure, even before any bowing columns have reached failure. Therefore, all the processes resulting in failure are taking place simultaneously, even though the failures of specific elements are not.
To a certain extent, though you are treating the global structure as non-rigid, and the local elements (perimeter columns) as rigid. If you are going to delve down into lower levels of detail, then your response should be that you think core deformation caused IB and that as far as you are concerned initiation occurred (x) minutes previously. OR you'd need to be clear about differentiating between an elemnt undergoing deformation and an element failing. The described NIST initation sequence focusses upon failures, not gradual deformations. South perimeter *failure* preceeds north perimeter *failure*.
You're trying to break a complex process down into a neatly-separated sequence of isolated steps.
Not particularly. The intention is to delve into
more detail, but there must be a start point in discussion and kind of basic agreement about general sequence.
That could easily boil down to...
Dave, did core failure cause IB, or did IB cause core failure ?
Which face failed first, south or north ?
Did all core columns fail instantly and simultaneously, or did failure propogate from one area to another over a period of time ?
Real life isn't that simple.
Very true.
