Cyclically and Biaxially Loaded Reinforced Concrete Slender Columns

The objective of this column study is to explore and examine the behavior of various cyclic compressive load levels on the ultimate strength, deflection, and moment-curvature characteristics of rein-forced concrete slender columns with bidirectional eccentricities. Furthermore, a part of this research is to develop a numerical analy-sis 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 are tested under cyclic axial compression with bidirectional eccentrici-ties. The main parameters of the column tests are the bidirectional eccentricities and its angle to the reference axis. The load pattern considered in this experimental study is cyclical, and the applied load is a full loading of cycles that is loading up to the envelope curve and then unloading down to nearly zero stress level. It should be noted that the cyclic axial compressive load with bidirectional eccentrici-ties considered is in the longitudinal direction, but not in the trans-verse 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 the present study.