An Experimental Study on the Behavior of Square Concrete-Filled High Strength Steel Tube Columns

The paper presents an experimental study on the behavior of square concrete-filled high strength steel tube columns until failure. Four specimens were tested to investigate the effect of high strength steel and plain strength concrete on the load carrying capacity of the square concrete-filled steel tube columns. The effect of the concrete which filled in the steel tube was also investigated. Also, the effect of high strength steel and the presence of concrete were also investigated. The main parameters in the tests were: (1) the ultimate strength of steel (800 Mpa), (2) the presence of concrete in steel tube (hollow steel tube and concrete-filled steel tube), and (3) slender ratio. The main objectives of these tests were three-step: (1) to describe a series of tests on composite columns, (2) to analyze the influence of several parameters, and (3) to compare the accuracy of the predictions by using the specifications in the code (AISC-LRFD, EC4 and AIJ etc.) for the design of high-strength composite columns. Experimental results indicate that the ultimate strength of steel and presence of concrete had significant influence on both the axial compressive load capacity and the ductile of the square steel tube