Cyclic axial stress-strain model for circular CFST columns under compression loading: Fid-Bau Portal

Cyclic axial stress-strain model for circular CFST columns under compression loading

Bhartiya, Rahul / Sahoo, Dipti Ranjan / Oinam, Romanbabu M.

Abstract This study presents an experimental investigation of twenty-seven numbers of concrete-filled steel tubular (CFST) columns under cyclic axial compression loading to investigate the influence of grade of concrete, length-to-depth ( $L / D$ ) ratio, and age of concrete on the cyclic axial performance of CFST columns. The $L / D$ ratios were varied in the range of 3–10, while diameter-to-thickness ( $D / t$ ) ratios of the tube were selected as 13 and 26. The main parameters studied were the peak axial strengths, displacement ductility, post-peak stiffness, and post-peak strengths of CFST columns. The backbone curves of CFST columns obtained from the cyclic tests were found to be similar to the monotonic load-deformation behavior. Test results were also compared with various confinement models available in the literature. A modified cyclic confinement model has been proposed in this study to accurately predict the cyclic behavior of CFST columns. The predicted stress-strain response using the developed confinement model matched well with the test results.

Highlights • Twenty-seven CFST columns were tested under cyclic axial compression loading. • Parameters studied were tube compactness ratios, slenderness ratios, concrete grades, and age of concrete. • Test results are compared with various confinement models available in the literature. • A cyclic stress-strain model has been proposed circular CFST columns.