Numerical simulation of RCC flat slab using improved constitutive laws in concrete damage plasticity

Abstract This study aims to minimize the sensitivity of finite element models to mesh characteristics in representing the uniaxial behavior of concrete using the Concrete Damage Plasticity (CDP) model and improve the accuracy of punching shear predictions in flat slabs. The study refined the formulations of the constitutive laws within the CDP model based on existing literature. These modifications were the strain corresponding to the compressive strength, the tensile stress-cracking strain relationship, and its coefficient <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>b</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>t</mml:mi> </mml:mrow> </mml:msub> </mml:math> . The refined model was employed to analyze the punching shear behavior in RC flat slabs using the finite element analysis software ABAQUS/Explicit, and its predictions were validated against 20 experimental test results obtained from the literature. The validation of the proposed model was conducted by comparing its predictions of punching shear behavior with experimental results, focusing on load-deflection curves, crack patterns, and reinforcement strains. The results indicated that the failure loads and displacements predicted by the FEA using the proposed model differed by 8% and 23%, respectively, from the experimental results. Furthermore, in comparison with the model adopted by Beaulieu et al (2023), the accuracy of the predicted failure loads using the proposed model improved by 7.3%, while the accuracy of displacements prediction increased by 13.3%. Therefore, the proposed model is deemed reliable for simulating RCC flat slabs and accurately capturing punching shear behavior. It also holds potential for use in further investigations and advanced analyses.