Numerical Study on Concrete-Filled Steel Tubes with Diagonal Binding Ribs and Longitudinal Stiffeners

Abstract

AbstractThe effect of ribs and stiffeners on axial load carrying capacity on nineteen concrete-filled steel tubular (CFST) column models and the performance of three unstiffened square CFST columns and two octagonal CFST columns under seismic load by nonlinear static analysis using ANSYS Workbench 16.2 was numerically studied. The models used for this study are unstiffened square CFST columns, diagonal binding rib stiffened square CFST columns, longitudinally stiffened [1] square CFST columns [2], and unstiffened octagonal CFST columns. CFST column was validated against the experimental results under axial load [3]. An increase in thickness of steel tube, stiffener and rib show higher load-carrying capacity. Square CFST columns have more axial load carrying capacity than octagonal CFST columns. Stiffened CFST column has a higher load carrying capacity than unstiffened CFST column. The diagonal rib stiffened CFST columns having ribs with square openings had higher strength than those with circular openings. The ultimate strengths of the diagonal rib stiffened CFST column slightly decreased when the opening diameter in ribs increased and when the opening spacing increased. The unstiffened square CFST columns with thicker steel tubes performed better under seismic load than unstiffened octagonal CFST columns.KeywordsDiagonal binding ribsStiffenersCFST columnSeismicAxialLongitudinalOctagonalSquareCircularUltimate strength