Serviceability criteria often control the design of normal composite beams. This is because they are usually designed to be as shallow as possible for a given span.
Deflection Limits allow you to control the amount of deflection in both composite beams and steel beams by applying either a relative or absolute limit to the deflection under different loading conditions.
A typical application of these settings might be:
not to apply any deflection limit to the slab loads, as this deflection can be handled through camber,
to apply the relative span/over limit for live load deflection, to meet code requirements,
possibly, to apply an absolute limit to the post composite deflection to ensure the overall deflection is not too large.
