Material nonlinear analysis of RC shear walls subject to monotonic loadings

This paper proposes an analytical model to simulate the nonlinear behavior of reinforced concrete (RC) structures subject to monotonic in-plane shear and normal stresses. Based on the force equilibrium, compatibility conditions, and bond stress–slip relationship between the reinforcement and the surrounding concrete, a criterion to consider the tension-stiffening effect is proposed using the concept of average stresses and strains. The material behavior of concrete is described by an orthotropic constitutive relation, focusing on the tension–compression region with tension-stiffening and compression softening effects defining the equivalent uniaxial stress–strain relation in the axes of orthotropy. The behavior of cracked concrete is described by a system of orthogonal cracks, which follows the principal strain directions and rotates according to the loading history. Finally, correlation studies between analytical results and available experimental data are conducted to assess the validity of the proposed models.