Response of Reinforced Concrete Panels under Uniaxial Tension

Abstract

This paper summarizes the results of an experimental project aimed at improving the current understanding of the response of cracked concrete. Twenty-three reinforced concrete panels of normal and high-strength concrete were tested in uniaxial tension. Three variables were examined : 1) reinforcement ratio ; 2) reinforcement (reinforcing bar) distribution ; and 3) concrete strength. Average stress-strain curves were recorded for all panels. Stress-strain curves of the reinforcing bars were determined by testing tensile coupons. Matrix strength at first cracking was calculated. Average contribution of the concrete matrix was obtained by subtracting the contribution of reinforcing bars from the response of the panels. Additional information on the cracking behavior in the panels was obtained from the measurements of the crack mouth opening displacement ofa single crack The matrix strength at first cracking was found to increase with decreasing spacing of reinforcing bars, but was independent of the reinforcement ratio. Reinforcing bar spacing did not influence the average contribution of concrete. For high-strength concrete panels, the concrete contribution decreased with increasing reinforcement ratio. Compared to normal-strength concrete, the average contribution of high-strength concrete was found to be higher during the multiple cracking phase, but decreased faster with increasing strains.