Axial compression performance of multi-cell concrete filled steel tubular flat columns

To enhance the axial compression performance of concrete filled steel tubular flat columns (CFSTFCs), a new multi-cell CFSTFC (MC-CFSTFC) constructed by hot-rolled section steel and internal steel plates was proposed. In this study, seven MC-CFSTFCs and two CFSTFCs were designed and tested under axial compression. The damage mechanism, failure mode, axial loadcarrying capacity and ductility of the MC-CFSTFC and CFSTFC were analysed and compared. The test results indicated that the proposed MC-CFSTFCs had a different damage mechanism and failure mode and better axial deformation ductility than the CFSTFCs. Increasing the sectional aspect ratio reduced the axial compression performance of the MC-CFSTFCs and CFSTFCs. Finally, the measured axial load-carrying capacities of MC-CFSTFCs and CFSTFCs were compared with the design methods in GB 50936, CECS 159, EC4, AS 5100.6, and AISC 360. CECS 159 and AISC 360 provided relatively accurate predictions.