Cyclically and Biaxially Loaded Reinforced Concrete Slender Columns

The objective of this study is to explore and examine the behavior of various cyclic compressive load levels on the ultimate strength, deflection, and moment-curvature characteristics of reinforced concrete slender columns with bidirectional eccentricities. Furthermore, a part of this research is to develop a numerical analysis that can simulate the behavior of reinforced concrete columns under combined biaxial bending and cyclic axial compression. For the experimental study, 4 ft. long reinforced concrete columns were tested under cyclic axial compression with bidirectional eccentricities. The main parameters of the column tests were the bidirectional eccentricities and the angle to the reference axis. The load pattern considered in this experimental study was cyclical, and the applied load was a full loading of cycles that was loaded up to the envelope curve and then unloaded down to nearly the zero stress level. It should be noted that the cyclic axial compressive load with bidirectional eccentricities considered was in the longitudinal direction, not in the transverse direction, with respect to the column axis. The experimental ultimate load, load-deflection, and moment-curvature curves are compared with the prediction from a computer model developed in this study.