Hybrid plasticity model for reinforced concrete in cyclic shear

A plasticity model was developed to address the cyclic behavior of reinforced concrete planar members. The plasticity model basically used multiple failure criteria to describe the isotropic damage of compressive crushing and the anisotropic damage of tensile cracking. New concepts of multiple fixed crack orientations, hybrid plasticity model, and degraded shear stiffness were introduced to describe the behavioral characteristics of reinforced concrete subject to cyclic loads, i.e. multiple tensile crack orientations and progressively rotating crack damage. Particularly, the proposed model is distinguished from existing plasticity models in that it can describe the characteristics of the tensile crack damage in cyclic shear: rotating crack damages under loading and fixed crack damages under unloading/reloading. The proposed model was implemented for finite element analysis and was verified by the comparisons with experiments of reinforced concrete shear panels and walls.