Creative Speculation

Their highly idealized model is not based on the maximum ability of the lower structure to resist all the kinetic energy. Rather it is based on the maximum ability of the lower structure to resist all the kinetic energy if it were delivered all at a single instant.

Here is a different way of thinking about it that shows their flaw. Assume that you can remove the upper structure and cut it into very small pieces. Then assume that you can drop each of those pieces, one at a time, from the appropriate height above the lower structure, approximately one floor's height, onto the lower structure. This will take a long time but when you've finished the lower structure will have absorbed the same amount of kinetic energy that Bazant purportedly proved it can't.

Clearly if that same amount of kinetic energy is delivered in this fashion the lower structure has no problem resisting it. No columns will be crushed. Why is this result different than Bazant's? Because Bazant assumes, without justification, that all the kinetic energy is delivered at one single instant. But the result under that assumption is not necessarily the same as the result if application of the kinetic energy is spread out over time.

Bazant has not demonstrated, has not attempted to demonstrate, the relationship between his idealized model that unrealistically delivers all the kinetic energy at once and the real life process in which the kinetic energy was delivered over some span of time.