Combined axial and flexural behavior of concrete-filled corrugated steel tubular columns

To investigate the performance of concrete-filled corrugated steel tubular (CFCST) columns under combined axial compression and bending, numerical and theoretical analyses were conducted in this paper. Firstly, a refined finite element model was established and validated against the existing test results. The stress distribution of steel and concrete with different eccentricities was then analyzed. It was found that the sectional area of concrete region under compression and the stress of corrugated steel plates decreased gradually with the increase of eccentricities. The impacts of cross-sectional dimensions, corrugation dimensions, and material strengths were studied through a parametric analysis. The results indicated that the effect of cross-sectional dimensions on the performance of CFCST columns was more significant than that of corrugation dimensions, and increasing the steel bar strength was more beneficial to improving the ultimate resistance of the CFCST column than increasing the concrete strength. Finally, a theoretical model of compression-bending performance of the CFCST column was established based on the sectional analysis method, and the N-M interaction curve was presented. The proposed N-M interaction curve could conservatively predict the load-bearing capacity of the CFCST column, and the error of 90% of the numerical examples was less than 10%, which could be used for the design of CFCST columns.