ABSTRACT
Before we develop a detailed solution for Mu and ϕu, it is instructive to present an approximate solution for a beam of a rectangular cross section. To obtain an approximate solution for the useful limit, we assume
1. The tensile reinforcement is at the yield stress. 2. The mean stress in the compressed concrete above the neutral axis is 0.7f ′c. 3. The centroid of the total normal force in the concrete is at 0.4c from the
extreme ber in compression (c being the depth to the neutral axis as indicated in Figure 14.4).
