Experimental behaviour of tapered CFST columns under combined compression and bending

Tapered concrete filled steel tubular (CFST) columns have been used in some spatial structures, however, research on the structural performance of such tapered composite columns under combined compression and bending is relatively seldom, and this paper thus intends to fill this knowledge gap through experimental investigations. A total of twenty-four tapered CFST specimens were tested under combined compression and bending, including twelve square columns and twelve circular ones. The test parameters included sectional type, tapered angle, slenderness ratio and load eccentricity. Typical failure modes, the load versus deformation relations, the strain development of tapered composite members and the influence of significant parameters were evaluated based on the testing results. Finally, simplified design method for predicting the load carrying capacity of tapered CFST column under combined compression and bending was discussed.