Strength and behaviour assessment of axially loaded concrete filled steel tubular stub columns

Abstract

As a result of the excellent performance under different loading conditions, concrete-filled steel tubular (CFST) stub columns are extensively used recently. The current study employs a 3D finite element analysis to assess the response of (CFST) stub columns when subjected to axial compression. The effect of some parameters of concrete and the confining steel tube where numerically investigated. The steel was considered as an elastic perfectly plastic material, whereas a damage plasticity behaviour was adopted for the concrete material. Analysis results suggested that the ultimate strength of concrete increases with the increase of its grade. On the other hand, increasing magnitudes of concrete grade caused a reduction in the ductility of the composite columns. Also, the increase in the steel yields stress, and the steel tube wall thickness contributes to an increase in the columns’ ultimate strength. However, they reduce the action of the concrete grade that increases the column’s ultimate strength. It was also noted that the ductility that the circular CFST stub columns showed is larger than that for square columns. Thus, the use of square CFST columns with high strength concrete, especially in seismically active areas, should be carefully considered.