Investigate Effect of the Parameters Compressive on Behavior of Concrete Filled Tubular Columns under Fire

Concrete-filled steel tubular columns have been extensively used in structures, owing to that they utilize the most favorable properties of both of constituent materials, ductility, large energy-absorption capacity, and good structural fire behavior. Concrete inside the steel tube enhances the stability of the steel tube, and the steel tube in turn provides effective lateral confinement to the concrete. Furthermore, the fire resistance of (CFT) columns is higher than that of hollow steel tubular columns, external protection being not needed in most cases. During a fire, the steel tube acts as a radiation shield to the concrete core and a steam layer in the steel-concrete boundary appears. This paper presents to investigate effect of the parameters compressive on behavior of concrete filled tubular (CFT) columns under fire by numerical simulations using ABAQUS software. Three different diameter to thickness ration of 54, 32 and 20 are considered in this study with two concrete s compressive strengths of 44 and 60 MPa. The measured compressive axial capacity is compared to their corresponding theoretical values predicted by four different international codes and standards. The result indicate that the effect of diameter to thickness ratio on the compressive behavior of the sections is greater than the effect of the other factors and also the axial capacity calculated by most of these codes reduce as the diameter to thickness ratio increases as verified by experimental results.