Creep analysis of concrete-filled steel tube columns under long-term loading by the method of 3D finite element

Based on the viscoelastic theory, this paper proposed the three-dimensional finite element model of creep of core concrete, in which a linear three parameter viscoelastic model was adopted. By the method of three-dimensional virtual laminated element, creep of concrete-filled steel tube columns under long-term loading was studied. The parameters of the proposed model were fitted, based on the experimental measurement. In the end, the influential regularities of concrete-filled steel tube columns under long-term axial and eccentric loads were studied by adopting the proposed model. The comparison between the test data and calculating results shows that they have a good agreement.