Final answer:
A UB section is more efficient in bending than a UC section when used as a long span simply supported floor beam supporting a concrete slab because of its geometric properties.
Step-by-step explanation:
A UB section is more efficient in bending than a UC section when used as a long span simply supported floor beam supporting a concrete slab because of its geometric properties.
UB sections have a greater depth and larger flanges compared to UC sections, which increases their bending strength and allows them to resist larger bending moments. Additionally, the larger flanges provide more surface area for the concrete slab to bond to, enhancing the overall structural integrity of the beam-slab system. This is especially important in long span applications where deflection control is crucial.