Abstract
A method for cost-optimum design based on ACI code provisions of singly reinforced rectangular beams is presented. The cost of steel reinforcement, concrete, and formwork is included in the formulation of the objective function. The behavioral constraints arise from strength and ductility, while the side constraints emanate from the practical limits on beam dimensions. A close-form solution of the optimization problem expresses the optimal values of steel ratio and section dimensions in terms of material costs and strength parameters, and permits development of parametric design curves. Overall flow diagram of the algorithm is also presented. Example problems illustrate the rationality, effectiveness, and simplicity of the method.