Generalised calibration and optimization of concrete damage plasticity model for finite element simulation of cracked reinforced concrete structures

Assessing reinforced concrete (RC) structures under various loading conditions requires precise numerical models capable of capturing the complex nonlinear behaviours of concrete, including cracking, crushing, tension stiffening, compression softening, stiffness degradation, and bond-slip effects. This paper introduces a generalized, calibrated, and optimized concrete damage plasticity model (CDPM) to enhance simulation accuracy for both monotonic and cyclic loads. The model is enhanced by incorporating RC crucial effects such as tensionstiffening and compression-softening and addressing the critical interdependencies, such as those between dilatancy and the damage model, as well as the influence of viscosity regulation and mesh sensitivity. This approach also systematically optimizes the calibration of critical parameters to improve the representation of concrete behaviour. The model is validated through a dual-scale approach, comparing its predictions to existing test data from the literature. Material-level validation involves comparison against uniaxial and cyclic compression, tension, and biaxial loading experiments, while structural-level validation involves simulations of RC beam-column joints and shear walls under both monotonic and cyclic loading conditions, incorporating considerations for bond slip. The effects of tension softening, tension-stiffening, dilation angle, and viscosity parameter regulation are also evaluated. The findings demonstrate that the model accurately replicates experimental results at both material and structural levels under monotonic and cyclic loading conditions. It effectively captures key aspects such as stiffness degradation and energy dissipation in reinforced concrete under cyclic loads. By incorporating essential features like compression-softening and tension-stiffening effects, selecting appropriate constitutive relations, and optimizing parameters and calibration, this model enhances the accuracy of simulating concrete behaviour. Overall, this enhancement in the CDPM provides a more efficient and precise approach for analysing concrete structures under diverse loading scenarios.