Steel ratios for cost optimum reinforced concrete beams

The amount of main-reinforcement steel in reinforced concrete beams is limited by maximum and minimum steel ratios. No guidance is given by design codes as how to choose the ratios within the permissible range. Using systematic direct search, the influence of various factors on the optimal steel ratio for single-reinforced concrete beams is studied. Using the design code of the American Concrete Institute, it is found that the most influential factors in selection of steel ratios are support conditions and material costs. Applied loads and yield strength of steel are shown to have some influence.