Eccentric Axial Load Test for High-Strength Composite Columns of Various Sectional Configurations

Abstract

Composite columns of various sectional configurations are studied to maximize the contribution of high-strength steel under compression-flexural loading. For concrete-encased steel (CES) columns, steel angles were placed at four corners of the cross-section and connected by various types of transverse reinforcements. In the case of a concrete-filled steel tube (CFT) column, a slender steel tube was stiffened by welding longitudinal bars. To verify structural capacities, eccentric axial load tests were performed for three concrete-encased steel angle (CES-A) columns and a stiffened concrete-filled slender steel tube (S-CFT) column, using Grade 800 MPa steel and 100 MPa concrete. The CES-A columns showed good structural performance in strength, flexural stiffness, and ductility due to the high contribution and good confinement effect of the corner steel angles and transverse reinforcement. In the S-CFT column the welded longitudinal bars successfully restrained local buckling of the slender steel tube so that the full plastic strength of the composite section developed.