Bearing Capacity of Stone-Lightweight Aggregate Concrete-Filled Steel Tubular Stub Column Subjected to Axial Compression

The objective of this research was to investigate the axial compression performance of stone-lightweight aggregate concrete-filled steel tubular (hereafter referred to as SLCFST for simplicity) stub columns. Ten specimens, five circular SLCFST (C-SLCFST) stub columns and five square SLCFST (S-SLCFST) stub columns, were tested using replacement ratios of normal gravel aggregate of between 0% and 100%, in increments of 25%. The influence of replacement ratio on axial compression performance and failure mode, ultimate bearing capacities and peak displacements was analysed. The results were compared, and show that under axial compression loading, strength damage occurs in SLCFST stub columns. The working process of SLCFST stub columns can be divided into four parts: an elastic stage, an elastic-plastic stage, a gentle descent stage and a plastic stage. The ultimate bearing capacities of the specimens were calculated and analysed based on existing design codes. By introducing the influence parameter of normal gravel replacement ratio, mathematical models for predicting the complete stress-strain compression curves of C-SLCFST and S-SLCFST stub columns were developed and verified.