Investigation on the Behavior of Concrete-Filled Rolled Steel Tubular Columns Under Axial Loads

In this paper, a numerical investigation on behavior of concrete in filled columns using nonlinear finite element method is done. Numerical results are verified using experimental results. Behavior of rolled steel tubes witch are filled with concrete of different strength on the axial applied loads is present. Effect of steel tubes thickness and confining stress are considered and the results are compared with concrete columns. The results showed that with increasing thickness of steel tubes, axial load capacity and confinement stress and ductility is increased and with increasing the concrete strength, confining stress and ductility is reduced. Specimens with different concrete strength of 30,60,80 MPaand different ratioare analyzed and all the specimens have the same length of 300 mm. The main objects are: 1) to investigate effect of prominence on axial load capacity. 2) to investigate the effect of different parameters like thickness of steel tubes, friction coefficient and the ratio of prominence area over total perimeter area. 3) to investigate effect of loading(i.e. loading concrete only or loading concrete and steel tubes simultaneous. 4) to investigate the ductility of columns.