North Tower Acceleration

[jesters]

170. I see what you're saying,

but I would prefer someone who knows more about these matters to comment on why it would be included as a separate value. Considering he goes into a fair amount of detail regarding the concrete, and refers to Greening's calculations, I would guess there's a pretty good reason for it. You can certainly have momentum loss without pulverization. The fact that the concrete was pulverized does seem to warrant additional energy expenditures.

As Ross states right in his paper:

"The analysis shows that the energies expended during the time period of the plastic shortening of the first storey height of the vertical columns is sufficient to exhaust the energy of the falling section and thereby arrest collapse. ...This also shows that collapse arrest is not dependent upon an expenditure of energy in concrete pulverisation, since even if this expenditure were disregarded, the input energy would be exhausted during plastic shortening of the second storeys affected. "

Either way, you're still ignoring the fact that Ross uses both Bazant's erroneous inputs and erroneous model and still comes up with an energy deficit that he considers to be a minimum value.