Tests on Concrete Filled Steel Tubular Columns with High Slenderness Ratio

The behavior of very slender concrete filled tubular columns and hollow tubular columns with circular sections subjected to axial load was investigated experimentally. A total of fifteen specimens including eleven concrete filled steel tubular columns and four hollow tubular columns were studied. The main objectives of these tests were twofold: first, to describe a series of tests on very slender composite columns; and secondly, to compare the accuracy of the predictions by using the recommendations of LRFD, AIJ, EC4 and DL/T 5085. Experimental results indicate that the concrete infill increases the compressive load capacity of the steel tube. The loading capacity of the concrete filled steel tubular columns can be conservatively predicted by using LRFD, AIJ, EC4 and DL/T 5085 recommendations for normal length columns.