Evaluation of Axial Performance of CFST Columns Filled with Ultra-High-Performance Concrete and Different Cross-Sectional Shapes

In this research, an analysis of the influence of the cross-section on CFST columns built with ultra-high-performance concrete was carried out. For this purpose, numerical simulations were performed on columns using three types of cross sections: circular, square, and octagonal. The study analyzes the impact of steel yield strength, concrete compressive strength, lateral pressure, and confining stress. The results show that as the yield strength of steel increases, the maximum axial load capacity of the columns increases. The trends reveal 7.46%, 4.47%, and 5.75% increases in the maximum axial load capacity for columns with circular, square, and octagonal cross-sections. Similarly, 16.85%, 9.39%, and 36.59% increases in lateral pressure were observed for the different section types. In general, columns with square sections have greater capacity to support axial loads, with increases of 11.42% and 23.98% compared to circular and octagonal sections. In addition, the compressive strength of concrete considerably influences the maximum axial load-carrying capacity of CFST columns. The results show that an increase in this property generates an increase of 19.55%, 22.86%, and 23.29% in the maximum axial load capacity for columns with circular, square, and octagonal sections. In general, the methodology used is a tool to analyze the axial load capacity of CFST columns, considering the mechanical properties of steel and concrete and the geometry of the cross-section.