Effect of limited tension stiffening in reinforced concrete elements under cyclic loads

The tension capacity in cracked concrete is not well defined in existing shear models for reinforced concrete (RC) membrane elements under cyclic reversed loading, and the shear strength of RC elements is consequently overestimated due to the deviated decreasing branch of envelope of cyclic tensile stress-strain relationship. In this paper, the cyclic effect of limited tension stiffening of cracked RC elements is evaluated by proposing an analytical model named as the cyclic tension-stiffening fixed-angle truss model (CTFTM). The proposed model, based on fixed-angle theory, integrates unloading and reloading rules and accumulated damage into the limited tension-stiffening effect under cyclic loading and considers the consequent local stress variation at crack surface. The cyclic effect of limited tension stiffening of RC elements is verified by comparing with experimental results in the literature. The predictions show good agreement, and the effect of biaxial loading is also examined.