Uniaxial model for simulating the cyclic behavior of reinforced concrete members

Abstract A new computational model is proposed within the lumped‐plasticity framework to simulate the lateral load‐deformation response of reinforced concrete members up to complete loss of lateral strength. The proposed model implements new features that enhance simulation fidelity of reinforced concrete members. It employs a cubic spline function to simulate the gradual changes of stiffness observed in the unloading‐reloading behavior of concrete members under seismic loading. The proposed model takes a different approach to simulating cyclic behavior from existing models, by utilizing an energy dissipation term as the central parameter to adjust the level of pinching in a response. The model replicates the amount of cyclic energy dissipation specified by the user, regardless of other parameters. It also automatically adjusts cyclic energy dissipation with increasing lateral deformations, to match experimental observations from concrete members. The model is equipped with deformation and energy‐based damage functions that can realistically capture stiffness and strength damage in concrete members, even under non‐symmetric cyclic loading. Using these functionalities, the model can adjust the lateral load‐deformation backbone response based on load‐history to account for short‐ or long‐duration non‐symmetric ground motion inputs. The proposed model is applicable for simulating the lateral shear or moment behaviors of reinforced concrete members, such as columns, beams, walls, and joints. The model is implemented in the open‐source simulation platform OpenSees as the CyclicReinforcedConcrete model.