Compressive testing and numerical modelling of concrete-filled aluminium tubular stub columns after exposure to high temperatures

In this study, a combination of experimental and numerical investigations was employed to examine the axial compressive performance of circular concrete-filled aluminium tubular (CFAT) stub columns after exposure to high temperatures. The influence of temperature variation and radius-to-thickness (D/t) on the load bearing capacity and failure mode of CFAT was highlighted. The test and FE results demonstrated that shear damage was observed in all the specimens, and the load to displacement curves can be roughly classified into elastic stage, elastic-plastic stage, plastic development stage, softening stage, and load-bearing capacity recovery stage. The applicability of the existing classical calculation theory for concrete filled steel tubular structures, as set out in European code, ACI, and AIJ to the studied CFAT was appraised. A simplified formula for the axial compressive capacity of CFAT column after exposure to high temperatures was proposed, and the accuracy of the formula was confirmed through statistical analysis.