ABSTRACT
The method proposed herein, for design of crosssections, consists of computing the required reinforcement area (Atot) supposing that all structural parameters are specified and, under given external loads, the cross section reaches its failure either in tension or compression. The problem is formulated by means of three equilibrium equations for the section. The condition of ultimate limit state is enforced by a compatibility equation imposing the maximum strain on the section to be equal to the limit strain of the corresponding material. These nonlinear equations are manipulated so that one of them is uncoupled and the Newton iterative strategy is applied only to the remaining coupled equilibrium equations in which total reinforcement steel area Atot , and the ultimate sectional curvatures φx and φy represents the unknowns.
