BEHAVIOR OF BIAXIALLY LOADED CONCRETE-ENCASED COMPOSITE COLUMNS

This paper reports the experimental test results of four small-scale c oncrete-encased I-shape steel columns subjected to biaxial bending mom ents and axial compressive load in single curvature. The composite col umn specimens, one short and three slender, had a square cross section . The effects of the eccentrically applied axial compressive force, sl enderness of the cross section, different material properties of concr ete and steel, and load-deflection and moment-curvature behavior on th e maximum load capacity of a composite column were examined. The test results were compared with the analytical results of the maximum load capacity obtained from a numerical analysis. The numerical analysis us es the finite differences method to establish the relationship between curvature and deflection. A computer program to perform the numerical analysis is used for the case of composite columns. The comparative r esults indicate that the analytical method and computer program used t o model and analyze the composite column specimens can accurately pred ict the maximum load capacity and deformation behavior of a pinned-end ed biaxially loaded concrete-encased steel column with axial compressi ve load in single curvature.