Compressive strength and ductility evaluation of high‐strength lightweight concrete confined with steel tubes

Abstract To estimate the high‐strength lightweight concrete filled in steel tubes (HSLCFST) columns, eighteen HSLCFST columns were prepared and tested under axial compression loads. The investigated parameters, including the wall thickness and the yield strength of steel tubes, as well as the compressive strength of HSLC, and their effects on the compression behavior were analyzed. The results showed that the typical failure modes of HSLCFST columns under axial compression included shear failure, local expansion failure, and uniform drum‐shaped buckling. The relationships between the failure modes and the lateral confinement of steel tubes were established. The axial stress‐axial strain curves of confined HSLC consisted of four stages: the elastic stage, the elastic‐to‐plastic stage, the descending stage, and the residual stage. The axial stress–strain curves of confined HSLC can be divided into two typical types according to the lateral confinement: the hardening stage and the soften stage. Furthermore, the prediction models for evaluating the compressive strength and ductility of confined HSLC were developed, which were suitable for evaluating the peak stress and axial deformation of confined HSLC.