Experiments and analytical simulation of bare-type CFT column bases

In this paper, three full-scaled specimens of interior CFT column bases were tested to investigate effects of axial load ratio (0.2–0.6) on the flexural behavior and the failure. The specimens were subjected to cyclic lateral loads at the column top under a constant axial load. In the experiment, the tensile yielding of anchor bolts, plastic bending of base plates and crushing of concrete and mortar were observed. As the axial load ratio increased, the flexural strength of the column base became larger, but concrete under the base plate failed in compression. In addition, the elastic-plastic behavior of the CFT column base was successfully simulated by an analysis using a proposed model, which took account of force-deformation relations of the anchor bolt, base plate, and concrete in the connection panel. Furthermore, an evaluation formula for the stiffness and flexural strength were proposed.