Seismic performance and correlation characteristics of reinforced concrete columns subjected to torsional moment, bending moment and axial force are clarified by experimental research. Interaction curves among those three sectional forces, which are necessary in nonlinear time history analysis, have not been proposed yet.
In this study 25 specimens with different rate of bending and torsional moments, pitch of hoop reinforcement are tested by newly developed loading system. The test specimen has 400^*400 mm cross section and 1600 mm length. The axial force is 0,5,10% of concrete compressive strength, i.e. 0,2,4 MPa. Pitches of hoop reinforcement are 30mm and 60mm. (volume ratios are 1.16% and 0.58% respectivily). Types of loading are pure bending, pure torsion and combined loading of bending moment and torsional moment. Bending and torsional moments are cyclic loadings, but axial forces are maitained to be constant during test.