Experimental investigation and design of thin-walled concrete-filled steel tubes subject to bending

A series of bending tests of thin-walled concrete-filled steel tubes (CFST) were presented in this study. A total of 4 specimens were tested, two square specimens and two rectangular specimens, with width to wall thickness ratio ranging from 50 to 100. The load–displacement curves, failure mode and ultimate capacity of test specimens were obtained. An analytical model was developed for the thin-walled CFSTs subjected to bending. Material properties of confined concrete, corner strength enhancement of cold-formed steel sections, residual stresses and plate local buckling were considered in the developed model. The proposed model was able to predict the behavior and strengths of test specimens with reasonable accuracy. In addition, the suitability of current AISC standard, Eurocode 4 and Hanʹs model for thin-walled CFSTs subjected to bending was also evaluated.