Analytical Behaviuor of Concrete Filled Steel Tubular Columns under Axial Compression

Steel-concrete composite columns are used extensively in high rise building and bridges, as a type of hybrid system. However this approach is a relatively new concept for construction industry. In concrete-filled steel tube (CFST) columns, the steel tube provides form work for the concrete, the concrete prevents local buckling of the steel tube wall. The load carrying capacity and behavior in compression,bending and shear are all superior to reinforced concrete. An analytical investigation of behavior of Concrete Filled Steel Tubes column and a theoretical design procedure according to EN 1994-1-1 Euro Code-4 are presented. The investigation has been carried out for rectangular and circular CFST columns under axial compression. The analytical model is developed to predict the capacity of CFST accounting for interaction between steel and concrete. The results obtained by theoretical calculation is validated using ANSYS 11.0 Multi physics utility tool. The results are illustrated by load carrying capacity table and modes of failure.