Behaviour of confined high strength concrete column subjected to concentric and eccentric loads

Abstract

In common practice, columns are subjected to a combination of an axial load and a bending moment in different direction. The only axially loaded columns are rarely occurred. However, most of the studies have concentrated on column which subjected to concentric load rather than eccentric load. In this study, the behaviour of confined high strength concrete columns under concentric and eccentric compression load was investigated. Twenty four high strength concrete short column specimens which internally reinforced with steel were cast in rectangular (140x140 mm) shape with 600 mm in height. The design of concretes compressive strength was 60 MPa. The specimens was categorised into three groups, which are control column, two layer metal straps columns and four layer metal straps columns. From each of the categories, the columns were tested with 25 mm and 50 mm eccentric load. The strength and the ductility of column are increased by external confinement. For concentric loaded column with two layers and four layers metal strap, the ultimate strength has increased 21% and 31%, respectively. Meanwhile, for the columns with eccentricity 25 mm that confined with two layers and four layers metal strap, the ultimate strength has increased with 17% and 21%, respectively.