Experimental study of damage evolution in cuboid stirrup-confined concrete

© 2015 RILEM This paper presents an experimental study on cuboid stirrup-confined concrete specimens under uniaxial monotonic loading and cyclic loading. The effects of stirrup volume ratio, stirrup yield strength, and concrete strength on damage evolution of the stirrup-confined concrete were investigated. The experimental results showed that the strength and ductility of concrete are improved by appropriate arrangement of the stirrup confinement. Firstly, with the increase of the stirrup volume ratio, the damage evolution of concrete can be relatively restrained. Secondly, higher stirrup yield strength usually leads to larger confining pressures and slower damage evolution. In contrast, higher concrete strength leads to higher brittleness, which accelerates damage evolution. Based on the experimental data, a plastic strain expression is obtained through curve fitting, and a damage evolution equation for stirrup-confined concrete is proposed by introducing a confinement factor (C). The comparisons results demonstrated that the proposed damage evolution curve can accurately describe the experimental results.