The behavior of cantilever steel pipe column under the cyclic loading that simulates seismic forces was analyzed using elasto-plastic FEM. The models analyzed are a simple steel pipe and a steel pipe reinforced by an encasing steel pipe. The results of FEM analysis are compared with those of the experiments. As a result, the following findings are obtained. 1. The effect of material stress-strain relationship on the results of FEM analysis is evident. The comparison of the case using kinematic hardening rule with the case of isotropic hardening rule shows that kinematic hardening rule qualitatively gives better results than isotropic hardening rule regarding the shape of hysteresis loop and maximum load carring capacity. 2. With kinematic hardening rule, it's possible to simulate the shape of hysteresis loop up to maximum load carring capacity and the mode of local buckling. 3. The confining by an encasing steel pipe as seen in the experiment can be simulated by this FEM analysis. 4. It's possible to estimate load carring capacity and δm/Sy with FEM analysis in this paper.
