Abstract:
In order to improve the compactness of core concrete fills in steel tubes and reduce shrinkage which can ensure better composite action and meet project needs, twenty-one self-stressing self-compacting and high-strength concrete filled steel tubular columns and three self-compacting and high-strength concrete filled steel tubular columns were designed and tested under eccentric compression. The factors influencing the failure mode of specimens, namely slenderness ratio, eccentricity ratio and initial self-stressing, were investigated. The load-strain curves and load-column deflection curves were analyzed. The results showed that the eccentrically compressed specimens mainly demonstrate flexible buckling failure; the ultimate bearing capacity of the specimen decreases with the increase in load eccentricity ratio and slenderness ratio. The ultimate bearing capacity of the self-stressing and self-compacting concrete filled steel tubular columns can be improved by 9.2%~11.7% with initial self-stressing ranging between 3 to 5 MPa. Based on the relevant domestic design codes, a predictive equation for the ultimate bearing capacity of self-stressing self-compacting and high-strength concrete filled steel tubular columns was derived through regression analysis, and can serve as a reference for practical engineering design.