EXPERIMENTAL INVESTIGATION ON MONOTONIC BEHAVIOR OF CIRCULAR STEEL STIFFENED COMPOSITE COLUMN UNDER COMPRESSION

Abstract

Concrete-filled square or rectangular thin-walled steel tubular columns are becoming increasingly attractive to be used in engineering practice. However, local buckling is more likely to occur for thin-walled tubes, and thus has adverse effects on strength and ductility for the composite columns. In order to improve their overall performance, one of the most effective stiffening measures is to provide longitudinal stiffeners for the steel tubes. In this experiment, Monotonic Behavior of Circular Steel Stiffened Composite Column under Compression is studied. In this study typical Fifty Four specimens of variable thickness t1&t2 and variable dia d1&d2 with piercing and also 54 specimens of thickness t1&t2, and variable dia d1&d2 without piercing is considered. For each Thickness combination of stiffeners at different position are selected that is for single stiffeners at mid span, from top h/3,from bottom h/3 and also for double stiffeners equispaced ,from top h/2&from bottom h/3,from top h/3&from bottom h/2. Experiments were carried out for four different cases : Hollow , Uncompacted Sand, Compacted Sand & Dry Cement & Dry Sand in order to know the behavior and buckling load of above said columns and tests were conducted under Monotonic loading. Major conclusion from this study are: Load carrying capacity of tubes with single stiffener with piercing at mid height found to decrease by 8-10% than hollow tubes of same diameter and thickness , but for with single stiffener without piercing at mid height found to increase by 2% than hollow tubes of same diameter and thickness . Also, Load carrying capacity of tubes with single stiffener without piercing at mid height was found to increase by 10-15% than pierced stiffener at mid height of same diameter and thickness.