Numerical parametric study on the uniaxial and biaxial compressive behavior of H-shaped steel reinforced concrete composite beam-columns

As a follow-up work of previous experimental efforts, this paper aims to further explore the compressive behavior of Steel Reinforced Concrete (SRC) composite beam-columns with assistance of nonlinear Finite Element Analysis. The FE model was developed in ABAQUS software and it delivered desirable accuracy after calibrating against the dataset collected from published literatures. The validated FE model was then employed to evaluate the fundamental performance of SRC beam-columns under uniaxial eccentric compression and biaxial eccentric compression. On top of that, the fiber section analysis was adopted to build the three-dimensional axial force-bending moment (N-M) interaction diagrams, followed by a parametric study to investigate the effect of material grade, steel ratio, cross-section geometry, load eccentricity and load inclination on the load-carrying capacity of SRC beam-columns, and disclose the complex biaxial interaction mechanism that is not well-considered in current design codes. Based on the numerical data generated from parametric study, the Support Vector Machine method is utilized to intelligently estimate the biaxial moment contours under varying load levels, which exhibits improved accuracy and consistency than the code-specified method and conventional empirical formulae.