Axial load behaviour of high-strength rectangular concrete-filled steel tubular stub columns

This paper presents an experimental investigation into the axial load behaviour of rectangular concrete-filled steel tubular (CFT) stub columns. A total of 26 specimens were tested under concentric compression. The primary test parameters were material strengths ( f ′ c = 55 − 106 MPa; f y=300 and 495 MPa) and cross-sectional aspect ratio (1.0–2.0). Favourable ductility performance was observed for all specimens during the tests. A comparison of axial load capacity between the tests and the design codes shows that ACI and AISC give safe estimation by 7 and 8%, respectively. On the other hand, EC4 overestimates the ultimate capacity of the specimens fabricated from mild steel and high-strength concrete. A fibre model is developed to evaluate the axial load behaviour of the specimens. Calibration of the model against the test data suggests that it can closely predict the non-linear behaviour of high-strength rectangular CFT stub columns.