Nonlinear analysis of RC beam subject to cyclic loading

A hysteretic moment-curvature relationship to simulate the behavior of a reinforced concrete (RC) beam under cyclic loading is introduced in this paper, and the nonlinear behavior of RC beams subjected to flexural cyclic loading is analyzed by means of the proposed model. Unlike previous moment-curvature models and the layered-section approach, the proposed model takes bond-slip effects into account by using the monotonic moment-curvature relationship constructed on the basis of the bond-slip relation and the corresponding equilibrium equation at each nodal point. In addition, in contrast to linearized hysteretic curves, the use of curved unloading and reloading branches inferred from the stress-strain relation of steel considering the Bauschinger effect gives more accurate structural responses. This follows a correct assessment of the energy-absorbing capacity of the structure at large deformations. The advantages of the proposed model, compared with the layered-section approach, may be in the reduction in calculation time and memory space in applications to large-frame structures with many degrees of freedom. Modifications of the moment-curvature relationship to reflect the fixed-end rotation and pinching effect are also introduced. Finally, correlation studies between analytical results and experimental studies are conducted to establish the validity of the proposed model.