Application of the DSC model for nonlinear analysis of reinforced concrete frames

A nonlinear finite element method with eight-noded isoparametric quadrilateral elements for concrete and two-noded elements for reinforcement was used to predict the behavior of reinforced concrete frame structures. The disturbed state concept (DSC) and the hierarchical single surface (HISS) plasticity model with the associated modified flow rule were used to characterize the constitutive behavior of concrete in both compression and tension. The DSC model allows for the characterization of non-associative behavior through the use of disturbance, and it computes microcracking during deformation, which eventually leads to fracture and failure. In the DSC model, the critical disturbance, Dc, identifies fracture and failure. Elastic perfectly plastic behavior is assumed in models of steel reinforcement. The DSC model was validated at two levels: (1) specimen and (2) practical boundary value problem. At the specimen level, predictions are obtained by integrating the incremental constitutive relations. The finite element procedure and the DSC model are used to obtain predictions for practical boundary value problems. Based on comparisons between DSC predictions and test data, the model is capable of providing highly satisfactory predictions.