STUDY ON THE SEISMIC PERFORMANCE OF REINFORCEDCONCRETE COLUMNS SUBJECTED TO TORSIONAL MOMENT,BENDING MOMENT AND AXIAL FORCE

摘要

During seismic excitation RC elements in three- dimensional structures such as arch ribs and L shape bridgepiers, torsional moments in addition to bending moments, shear and axial forces affect the member. Interactioncurves among those three sectional forces to use in nonlinear time history analysis has not been clarifiedyet.In this paper 9 test models with different bending and torsional moments, pitch of hoop lateral tie are testedby newly developed loading machine. The test model has 400*400 mm cross section and 1600 mm length.The axial forces are 10% of target compressive strength of concrete, i.e. 4 MPa. Pitch of hoop lateral tie is30mm or 60mm. Type of loading are pure bending, pure torsion and combined loading of moment andtorsion.Load deformation relationship, strain of reinforcement, crack and strain of surface, distribution of curvatureand unit angle of twist, energy absorption and equivalent damping ratios obtained by these loading test areshown in detail.