STUDY ON INFLUENCE OF HOLLOW RATIO TO BEARING CAPACITY OF H-CFST

The influence of sectional parameters to ultimate bearing capacity of hollow-concrete-filled steel tube (H-CFST) under axial loading is investigated through 55 test specimens，and the influence of hollow ratio to stress-strain relations is analyzed. The experimental results show that ultimate bearing capacity of circular section specimens is higher than that of other section specimens, the results also show that the higher the hollow ratio is, the more flat the descending segments of stress-strain curves is, and the shorter the elastic-plastic stage is, the lower the ultimate bearing capacity is. This implies that the continuity of H-CFST is sound with the change of sectional parameters. Contrasting with the experimental results, formula used to calculate composite standard compressive strength is proved to be correct.