Behaviour of eccentrically loaded high-strength rectangular concrete-filled steel tubular columns

This paper presents an experimental and analytical study of the behaviour of high-strength rectangular concrete-filled steel tubular (CFT) columns subjected to eccentric loading. Four slender and 16 stub CFT columns were tested to investigate their structural behaviour. The test parameters were material strengths (fy=495MPa,fc′=60MPa), cross-sectional aspect ratio (1.0–2.0), slenderness ratio (10 and 60) and load eccentricity ratio (e/H=0.10–0.42e/H=0.10–0.42). Favourable ductility performance was observed for all specimens during the tests. Experimental failure loads are employed to calibrate the specifications in the design codes EC4, ACI and AISC. Results show that EC4 overestimates the failure loads of the specimens by 4%. ACI and AISC conservatively predict the failure loads by 14% and 24%, respectively. An analytical model is developed to predict the behaviour of high-strength rectangular CFT columns subjected to eccentric loading. Calibration of the model against the test results shows that it closely estimates the ultimate capacities of the columns by 3%.