A concrete plasticity model with elliptic failure surface and independent hardening/softening

A plasticity-based concrete model is proposed. The failure surface is elliptic in the <i>&#963;</i>-<i>&#964;</i> stress space. Independent hardening as well as softening is assumed in tension, compression, and shear. The nonlinear inelastic action initiates from the origin in the <i>&#963;</i>-<i>&#949;</i> (<i>&#964;</i>-<i>&#947;</i>) diagram. Several parametesr are incorporated to control hardening/softening regions. The model is incorporated into a nonlinear finite element program along with other classical models. Several examples are solved and the results are compared with experimental data nd other failure criteria. &#34;Reasonable results&#34; and stable solutions are obtained for different types of reinforced concrete oriented structures.