Complete nonlinear response of reinforced concrete beams under cyclic loading

Complete nonlinear analysis is carried out for cyclically loaded reinforced concrete (RC) beams made of normal and high-strength concrete. The loading stage covers not only the pre-peak stage but also the post-peak stage in particular. The analysis is based on a numerical method that employs the actual stress-strain curves and takes into account the stress-path dependence of concrete and steel reinforcement. The complete nonlinear behavior of RC beams under both non-reversed and reversed cyclic loading is studied based on the moment-curvature relationship obtained. Generally, the response under cyclic loading is found to be dependent on the loading path in bending. The variation of neutral axis depth is different for under- and over- rei n forced sections during cyclic loading. The Bauschinger effect of steel reinforcement is insigniticant for non-reversed cyclic loading but notable for reversed cyclic loading, especially when the loading extends into the post-peak stage. The beneficial effects of concrete tension stiffening are only observed at the service stage and are more significant for under-reinforced RC beams than over-reinforced ones. Copyright (C) 2007 John Wiley & Sons, Ltd.