Originally Posted by GregoryUrich
Actually it is a paper written for children and for the sake of children.
If one wall column tries to deflect outward, while the adjacent ones remain in position, the spandrels will try to prevent this deflection (in tension or compression). If the whole wall deflects outward (all the floors are disconnected), evidently the spandrels have no real effect, except at the corners of the building.
The mass calculation is, as shown, superficial to enable approximate, static stresses to be computed. But the value is close enough.
I have not seen any results of tests of steel from the initiation zone or, for that matter, any pieces from the initiation zone that show sign of buckling, deformation, being affected by heat, etc. Heat evidently affects steel, and for the sake of simplicity, it is assumed that heat contributed to the failure of some columns. My personal opinion is that in that case the load carried on the failed columns would be transferred to adjacent intact columns with a completely different result.
Bazant apparently assumes that both the structure below
the initiation zone (A) and the structure above
the initiation zone (B) are extremely stiff (!) and that (B) impacts (A) with an enormous
energy and significant
speed and that (A) then collapses like a house of cards. What happens to (B) is not clear.
In my article for children it is shown that the enormous energy corresponds to maximum 40 kgs of diesel oil used efficiently and that the significant speed is that of a child on a bike running into a wall (10 km/h) so there isn't a real big impact between (B) and (A). It is just like children (B) jumping on a bed (A). Not a hammer (B) hitting a nail (A). Bazant got it all wrong.
It is thanks to Gregory Urich's (and others) kind comments that article ( http://heiwaco.tripod.com/nist.htm
) is what it is even if I am of course responsible for facts and conclusion.
The conclusion is evidently a recommendation to correct the Nist and Bazant reports ... for the sake of our children.
And nobody has debunked that conclusion, I am glad to see.