Combined Membrane and Flexural Reinforcement in Plates and Shells

A plate or shell element subjected to membrane forces $N_x\text{,}$ $N_y\text{,}$ $N_{\mathrm{xy}}$ and bending moments $M_x\text{,}$ $M_y\text{,}$ $M_{\mathrm{xy}}\text{,}$ is considered. Based on equilibrium considerations, equations for capacities of top and bottom reinforcements in two orthogonal directions have been derived. An iterative method is suggested for calculating the design capacities. The proposed equations are more general and rigorous than those derived for membrane reinforcement alone and those for flexure only. For the membrane alone case, the proposed equations degenerate into the previously derived equations. For the latter, it is shown that the present practice of designing flexural reinforcement may underestimate the required capacity.