Experimental evaluation of high-strength concrete-filled steel rectangular tube columns under axial compression

Abstract

This paper presents the effect of the high-strength concrete on the behavior and strength of concrete-filled steel tube (CFST) columns. To evaluate the structural performance, load-axial shortening responses, failure modes and axial load capacity are performed for ten high-strength concrete-filled steel tube (HSCFT) columns. All of the columns are 750 mm in height, and have compressive strength of 66 MPa. Test parameters included the wall thicknesses of the rectangular tube (3.0 mm, 4.5 mm and 6.0 mm) and three different of rectangular cross-sections (150×50 mm, 150×75 mm and 150×100 mm). From the experimental results, it is indicate that the load-axial shortening response of the columns have a linear behavior up to approximately 80-90% of their axial load capacity. Then, the behavior of the HSCFT columns is nonlinear with a very large deformation before failure. It is also shown that the axial load capacity and ductility of the HSCFT columns are increased significantly compared to the RC columns (reference columns), depending mainly on the wall thickness and cross-section of the hollow steel tube. Finally, by comparing the axial load capacity of the test results with those obtained from the AISC/LRFD design equation, the comparison results show that calculation formula in AISC/LRFD specification can be applied to compute the axial load capacity of HSCFT columns under axial compression.