Effect of axial load on flexural behaviour of cyclically loaded RC columns

The flexural behaviour of symmetrically reinforced concrete (RC) columns cast of normal- and high-strength concrete under both monotonic and cyclic loading is studied based on an analytical procedure, which employs the actual stress-strain curves and takes into account the stress-path dependence of concrete and steel reinforcement. The analysis is particularly extended into the post-peak stage with large inelastic deformation at various applied axial load level. The effect of axial load on their complete flexural behaviour is then identified based on the results obtained. The axial load is found to have fairly large effect on the flexural behaviour of RC columns under both monotonic and cyclic loading. Such effects are discussed through examination of various aspects including the moment-curvature relationship, moment capacity, flexural ductility, variation of neutral axis depth and steel stress.