Abstract
Columns are subjected to bi-axial bending moment, since buildings behave 3-dimensionally under seismic excitations. However, only few researches on post local buckling and deterioration behavior of RHS columns under bi-directional horizontal forces have been reported. In this study, at first, a simple horizontal loading protocol was proposed based on the investigation of random horizontal displacement orbits obtained by elasto-plastic response analyses of multi-story steel frames subjected to bi-directional horizontal ground motions. After that, using the simple loading protocol, a series of tests on RHS columns subjected to bi-directional horizontal cyclic loading and constant axial force were conducted. Experimental results were compared with analytical results using multiple shear spring (MSS) model.
