Nonlinear analysis of RC shear walls considering tension-stiffening effect

An analytical model which can simulate the nonlinear behavior of reinforced concrete (RC) structures (such as panels and shear walls) subjected to in- plane shear and normal stresses is introduced. Based on the concept of equi valent uniaxial strain. constitutive relations of concrete are presented in the axes of orthotropy which coincide with the principal axes of total str ain and rotate according to the loading history. The proposed model include s the description of biaxial failure criteria which show compressive streng th enhancement and tensile resistance reduction effects for the stress stat es of biaxial compression and tension-compression, respectively. After tens ile cracking, concrete compressive strength degradation was implemented and the tensile capacity of concrete maintained by the reinforcing steel (tens ion-stiffening effect) is considered. Using the concept of average stresses and strains, a criterion is proposed to simulate the tension-stiffening ef fect based on the force equilibriums, compatibility conditions, and bond st ress-slip relationship between reinforcement and the surrounding concrete. The finite element model predictions are validated by comparison with avail able experimental data. In addition, correlation studies between analytical results and experimental values from idealized shear panel tests were cond ucted. Load-displacement relations of shear panel beams and walls under var ious stress conditions are then evaluated to verify the soundness of the pr oposed model. (C) 2001 Elsevier Science Ltd. All rights reserved.