Application of a lumped dissipation model to reinforced concrete structures with the consideration of residual strains and cycles of hysteresis

The nonlinear analysis model for reinforced concrete plane frame structures is based on the simplified concept of the localization of irreversible physical processes at previously definite zones, denominated here as generalized hinges.However, when both damage due to the microcracking of concrete and sliding mechanisms (aggregate interlocking) at crack surfaces are taken into consideration, hysteresis loops can be reproduced if the loading history includes unloading cycles.The thermodynamic approach of the model is herein developed with reference to generalized variables due to its application in the framework of the classical theory of bars under bending load.According to this model, there are three scalar variables: a damage variable, the plastic rotation of the section and the sliding-associated rotation of the section.By comparison with available experimental responses, the numerical examples illustrate the good performance of the model.