Bearing capacity of hot-rolled H-section steel composite columns under axial compression

Hot-rolled H-section steel composite column is a kind of steel-concrete composite section member composed of hot-rolled H-section steel and steel plate welded together. In order to investigate the bearing capacity of the composite columns under axial compression, three hot-rolled H-section steel composite short columns were designed and tested under axial compression. The failure modes, load-displacement curves and load-strain curves of the specimens under axial compression were analyzed. A refined finite element (FE) model was established and validated, and the parametric analysis were carried out to investigate the three key parameters including the steel strength, concrete strength and the ratio of length to thickness. The results show that the ductility of hot-rolled H-section steel composite columns is very good, but the outward flanges were subjected to weak constraint and local buckling occurs first in it. And the welds of the H-section flanges with large width to thickness ratio in the middle section of the specimen, which is prone to local stability problems. And the FE model can accurately simulate the failure mode and load-displacement curve of specimens under axial compression. The concrete strength grades were considered from C20 to C90 and the steel strength grades were considered from Q235 to Q420, based on the experimental and FE analysis results, the design methods for calculating the bearing capacity of short columns and stability bearing capacity of the medium and long columns under axial compression are proposed, and the predicted results of the design method are in good agreement with the experimental and FE analysis results. © 2020, Editorial Office of Journal of Building Structures. All right reserved.