Reinforced concrete slabs behave differently depending on the stiffness of the supporting beams. Flexible beams make slabs act like flat slabs, while stiff beams cause them to behave like ordinary beams. When the long span to short span ratio is low, the slab shows two-way behavior, but as the ratio increases, it becomes one-way. The current design code underestimates internal loading for slabs supported by flexible beams and overestimates it for slabs supported by stiff beams with large span ratios.