Behaviour of Double Skinned Composite Columns with Concrete FilledTubular Columns

This paper comprises of the experimental study of five (5) double skinned concrete filled steel tubular (DSCFT ) columns of concentrically placed circular sections filled with self-compacting concrete (SCC). Tests on the specimens were made by applying axial loads. The main experimental parameter varied for columns were slenderness ratio. The test results of DSCFT columns are compared with another five (5) concrete filled tube (CFT) columns of same area of steel (Ast) and outer diameter as in DSCFT columns. Both filled with self-compacting concrete of grade M50. Testing of specimens investigates the behaviour on load deflection, confinement effect, and the strength of the columns. Various characteristics such as stiffness, ductility and failure mode are also discussed with the help of load deflection curves. The comparison with concrete filled tube (CFT) to the double skinned concrete filled tube (DSCFT) columns likely to be show that DSCFT columns are similar to CFT columns in performance and DSCFT shows better in cost concern than CFT. Theoretical analysis was also done and compared with the experimental results. Comparison of various codes like (EC4, LRFD, ACI) was also done. The results reveal that EC4 is better predictable than others). An ANSYS modelling was also done for two specimens to calibrate the test results obtained from experiments. The results from the experimental study were compared with the ANSYS results. The result shows that there is little difference in deformations between the ANSYS and experimental results.