The design of RC members with nontraditional methods is demanding due to the large number of unknown variables inherent in the design process. The complexity of the RC beam design optimization problem has led to many oversimplified models, so that the current metaheuristic search algorithms can deal with it efficiently. In this paper, the optimization design model of RC beams has been introduced by new design variables, while augmented others; accordingly enhanced the solving algorithm. A new enhanced parameter-setting-free harmony search algorithm has been proposed to solve the model. Furthermore, the tackled optimization objectives were the minimization of cost, weight, and cost–weight simultaneously for designing regular or high-strength concrete beams.