الفهرس 
Behavior of Square Hollow Steel ColumnsOnly 14 pages are availabe for public view
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Abstract
Concrete-filled steel tube (CFST) columns can provide excellent structural properties such as high strength and high ductility. The main objective of this study was to predict the nonlinear performance and ultimate capacity of the stiffened square hollow and (CFST) columns under axial compression loading. The available analytical methods neglected the effect of stiffener’s length when calculating stiffened hollow steel sections axial capacity. Therefore, an extensive study was conducted on the effect of stiffener length on ultimate capacity of steel columns having box hollow sections. Also, the effect of different numbers of stiffeners on ultimate capacity of steel columns considering five different grades of steel was numerically studied using nonlinear finite element analysis.
Regarding to (CFST) columns, theeffect of the stiffeners and width to thickness ratio (B⁄t) for the steel tube on the concrete confinementwasinvestigated.In addition, study effect of the concrete infill on the local buckling of the steel tube by comparing the stress-strain curves for steel tubes in case of the hollow and CFST columns. As a major result of the conducted analysis taking into account the studied parameters, a novel equation was proposed to predict the ultimate capacity of the box steel hollow and the (CFST)columns.The new equationstake into account effect of the local buckling, the contribution of stiffeners, and the concrete confinement on the CFST columns.The finite element modelsbuilt in this study for the hollow steel and the (CFST) columns were verified against the available experimental data under axial compression and showed good agreement.