Shear Behaviour of Ordinary Strength RC Slender Beams

Abstract

This report presents the results of an experimental study to understand the shear behaviour of concrete beams and to establish minimum shear reinforcement requirement so as to ensure that beams exhibit their full flexural capacity. The study investigates the effects of shear span to depth ratio and shear reinforcement ratio on the shear strength of RC slender beams. The experimental program is divided into four groups of two beams each based on ACI code provisions, equations proposed by Prodromos Zararis and modified equations of Zararis. Two beams were cast without shear reinforcement for reference and comparison. The samples in each group were tested at a/d ratio of 3.0 with moderate longitudinal reinforcement. Test results show that the Modified Zararis equation gives more accurate prediction of shear capacity of RC beams as compared to ACI code and Zararis’ equation. Based on the test data, minimum shear reinforcement that allows the development of nominal flexural capacity in RC beams was found. Accordingly, a new equation for minimum shear reinforcement is proposed which incorporates all contributing factors.