Effect of Concrete Compressive Strength and Compression Reinforcement in Compression Zone on the Ductility of Reinforced Concrete Beams

Abstract

Ductility is a mechanical property used to describe the extent to which materials can be deformed plastically without fracture giving warning of impending failure. In this paper the effect of increasing the strength in the compression zone of reinforced concrete beams on ductility was investigated. Seven reinforced concrete beams were tested for this purpose. The tested beams were divided into two groups depending on the manner at which the strength of the compression zone was increased. In the first group, the increase was done by increasing the amount of compression reinforcement. Four ratios of compression reinforcement were adopted. In the second group, the increase in the strength of the compression zone was done by increasing the concrete compressive strength in the upper third of the cross section which was subjected to compression stresses. Four compressive strengths were adopted .One beam was used as reference for the two groups. It was found that, the compression zone strengthening, by the two manners, increases both strength and ductility of the beams; but the increases due to increase the ratio of compressive reinforcement is higher and more safety than that attained due to increasing concrete compressive strength.