Effects of concrete grade and steel yield strength on flexural ductility of reinforced concrete beams

Abstract

A previously established theoretical equation correlating the flexural ductility of a reinforced concrete beam section to the steel ratios and the concrete strength has been extended to account for the effects of the tension and compression steel yield strengths by means of a parametric study. Through the study, it was revealed that at a fixed degree of the beam section being under-or over-reinforced, the flexural ductility decreases slightly with the tension steel yield strength as well as the concrete strength but increases slightly with the compression steel yield strength. From charts plotting the flexural strength and flexural ductility that could be simultaneously achieved by a beam section, it was evident that the use of a higher concrete strength could increase either the flexural strength or the flexural ductility or both. On the other hand, at a given flexural strength, a higher tension steel yield strength would lead to lower flexural ductility while a higher compression steel yield strength would lead to higher flexural ductility. Lastly, a simple method of designing beam sections to meet any specified flexural ductility requirement has been proposed.