Behaviour of Light Gauge Steel Fluted Columns Infilled with Nano Alumina Concrete

Abstract

Concrete Filled Steel Tube (CFST) is a composite member developed about 40 years ago, which can resist the load due to the composite action of steel and concrete. The integral behavior of the concrete and steel tube elements makes it a very cost-effective alternative. Attempts have been made to use this composite structural element as a column with the provision of flutes on the steel tube which improves both the aesthetics and surface area of the steel tube in which the moment of inertia is sufficiently increased. The experimental, analytical and theoretical investigation was performed on the CFST column with the provision of flutes. The steel tube of 0.6mm, 0.8mm, and 1mm, flute shapes of rectangular triangular, and trapezoidal, number of flutes of 3, 4, and 5, concrete type of M30 and M40 conventional and Nano Alumina (NA) concrete were selected for the parametric study. The load vs. axial shortening, load vs. deflection, load vs. strain, bond-slip characteristics, stiffness, and ductility of all the column specimens were studied. The hollow steel columns can perform better with infill concrete irrespective of the thickness of the steel tube, number and shape of the flutes. However, the hollow steel column offers better performance with Nano Alumina (NA) concrete than the conventional concrete infill column in terms of load carrying capacity, axial shortening, deflection, and strain newline