This paper presents the numerical part of the research program on concrete-filled steel columns. Nonlinear, three dimensional FE analysis of axial compression, was conducted using the finite element program ABAQUS. The numerical results were validated through comparison with experimental data in terms of ultimate loading and deformation modes. Modeling related problems such as the definition of boundary conditions, imperfections, concrete-steel interaction, material representation and others are investigated using a comprehensive parametric study. The developed FE models will be used for an enhanced interpretation of experiments and for the predictive study of cases not included in the experimental testing.

The purpose of this study is to investigate a structure’s response to blast loading when composite columns are used instead of conventional reinforced concrete (RC) cross sections and when a conventional structure is retrofitted with braces. The study includes conducting dynamic analyses on three different structures: a conventional reference RC structure, a modified structure utilizing composite columns, and a modified structure retrofitted with steel braces. The two modified structures were designed in order to investigate their performance when subjected to blast loading compared to the conventional design. During the dynamic analyses, the structures were exposed to simulated blast loads of multiple intensities using the finite-element modelling software, SeismoStruct. To evaluate their performance, the responses of the modified structures were analyzed and compared with the response of the conventional structure. It was concluded that both the structure with composite columns and the steel brace structure experienced less damage than the conventional model. The best performance was obtained through the steel brace structure.