Mechanical performance of eccentrically loaded pre-stressing concrete filled circular steel tube columns by means of expansive cement

This paper presents experimental and numerical investigations of pre-stressed concrete filled circular steel tube columns by means of expansive (PCFT) under eccentric loading. Conventional concrete filled steel tube (CFT) specimens are also tested in this paper just for comparison purposes. Based on the steel follow-up strengthening and concrete bounding surface constitutive relationships, this paper writes a nonlinear finite element program for calculating complete load mid-height deflection curves of eccentrically loaded PCFT/CFT columns. A good agreement is obtained between the calculated and test results. The results indicate that the eccentrically loaded PCFT columns generally have higher load carrying capacities than the CFT ones when other parameters are kept the same. But by increasing the load eccentricity ratio, the difference of load carrying capacity between them decreases. Other factors such as pre-stress, load eccentricity ratio, and steel ratio, etc. are also investigated.