California Reinforcing Steel Contractor (C-50 License) Practice Exam 2026 - Free Reinforcing Steel Contractor License Practice Questions and Study Guide

Reinforced concrete joist floors are built as a series of shallow beams (ribs) running across the span, with a top concrete slab poured over them. The whole system is often cast in one operation so the ribs, the top slab, and the supporting beams become a single monolithic unit. This rib-and-slab arrangement is what gives the floor its characteristic line of small beams supporting a continuous top slab. Flat plate slabs and flat slabs lack that ribbed network, while waffle slabs use a grid of ribs in two directions to form a waffle pattern, not the single-direction rib system described here.