Comment by sameerds

From the GP comment:

> Engineers design bridges with built-in safety margins in order to guard against unforeseen circumstances (unexpectedly high winds, corrosion causing joints to weaken, a traffic accident severing support cables, et cetera)

I am not a mechanical engineer, but none of these examples look like smooth functions to me. I would expect that an unexpectedly high wind can cause your structure to move in way that is not covered by your model at all, at which point it could just show a sudden non-linear response to the event.