HYSTERETIC BEHAVIOR OF THIN-WALLED CIRCULAR STEEL COLUMNS UNDER CYCLIC BI-AXIAL LOADING

Abstract

A cyclic bi-axial loading experiment has been carried out to examine the ultimate seismic behavior of thin-walled steel circular columns by using the accurate 3D-loading system recently developed by authors. The cyclic circular loading is adopted as one of the severest bi-axial loading patterns for circular columns. The results of the experiments are also used to confirm the applicability of the nonlinear FEM shell analysis where the three-surface cyclic plasticity constitutive model is implemented. With the nonlinear FEM analysis as well as the experiment, the potential decrease in the maximum horizontal restoring force and ductility of circular columns under cyclic bi-axial loading are quantitatively evaluated in comparison with that under in-plane cyclic loading.