3D Numerical Simulation of Nonlinear Behavior of RC Beam-Column Joint Under Monotonic Lateral Loading

Reinforced concrete beam–column joints govern the stiffness, ductility, and collapse mechanisms of frame systems under lateral loading. Although many numerical studies have examined joint behavior, few have systematically calibrated three-dimensional damage–plasticity models against detailed experimental benchmarks while quantifying both strength and energy dissipation. This study develops and calibrates a three-dimensional LS-DYNA model of an interior RC beam–column joint based on specimen KJ-08, using MAT_273 Concrete Damage Plasticity for concrete and MAT_003 Plastic Kinematic for reinforcement under monotonic quasi-static loading. Model calibration is performed with respect to initial stiffness, peak load, displacement at peak, crack patterns, and energy dissipation. The calibrated model predicts a peak lateral load of 206 kN and a peak-load displacement of 32 mm, differing from the experimental values by 3.52% and 11.1%, respectively, while the predicted energy dissipation of 16,680 kN·mm is within 2.32% of the test result. Compared with previously reported numerical models, the calibrated CDPM formulation provides the closest overall agreement in both stiffness and energy dissipation capacity. The results confirm that inelastic deformation, principal tensile stress, and tensile damage localize within the joint core, with reinforcement stresses approaching yield and strains entering the hardening range, indicating a ductile shear–flexure failure mechanism. These findings demonstrate that a carefully calibrated LS-DYNA CDPM model can serve as a reliable analytical tool for assessing joint detailing and confinement requirements in performance-based design of RC frame joints.