EFFECTS OF INITIAL STRESS OF STEEL TUBES ON AXIAL COMPRESSION RIGIDITY AND FLEXURAL RIGIDITY OF CONCRETE-FILLED STEEL TUBULAR MEMBERS

Axial compression regidity and flexural rigidity of concrete-filled steel tubular are very important parameters for seismic behavior analysis. An attempt to predict the load-deformation behavior of concrete-filled steel tubular axial loaded members and pure bending members with the effects of initial stress in the steel tubes considered is proposed in this paper.Based on the theoretical model, influence of the initial stress coefficient, sectional steel ratio, as well as strength of the materials is discussed. Finally, formulas for the calculation of the bending rigidity of concrete- filled steel tubular members with the effects of initial stress in the steel tubes considered are developed.