Creep computation module of self-stressing concrete-filled steel tube under axial load

To correctly predict the creep and its effect on the long-term mechanical performance of self-stressing concrete-filled steel tube,the creep computation module of the steel tube under axial load was analyzed by theory and tests.A numerical model to analyze the deformation of self-stressing concrete-filled steel tube under long-term loading was established using age-adjusted effective modulus method.It is showed that the ultimate bearing capacity of self-stressing concrete-filled steel tube subjected to the load for one year is higher than that of the sample without load,and the numerical model provided can simulate the creep test results well.Compared with the common concrete,the long-term deformation of self-stressing core concrete restrained by steel tube is very small,but the stress redistribution between steel tube and concrete is correspondingly large.The area of steel tube to concrete core ratio has more remarkable effect on the long-term deformation of self-stressing concrete-filled steel tube than other factors.