There are structural design manoeuvres specified in the regs which generate loads in all axes, but only those in the vertical axis are predicated upon specific 'g' levels. The assumption is basically that crews will not induce sustained lateral 'g' on themselves, and so only the dynamic manoeuvres are considered.
Cyclical loads are considered in the context of fatigue life calcs, and are in terms of a best estimate of normal operating loads, whereas the design manoeuvres are intended to be extreme/worst case conditions. Which is why you can do a design manoeuvre "once", but fly normally for tens or hundreds of thousands of hours ... in theory.
If you get sophisticated about fatigue life, you end up considering different missions as imposing different levels of cyclic loads, and consuming different amounts of fatigue life per flight hour. The RAF "Fatigue Index" system assigns different weightings per flight hour to better manage fleet fatigue. So a air combat training flight counts for more fatigue than a navigation flight of the same duration, say.