Local Buckling of Axially Compressed Welded H-Section Stub Columns Using Q420-Q960 Steel

There is a lack of reliable research regarding the current engineering specifications considering the broad applications of high-strength steel (HSS) in civil engineering. Axial compression tests were performed on 12 HSS welded H-section stub columns using Q420-Q960 grade steels to study their local buckling behavior. In addition, we performed a parametric analysis using a finite-element model (FEM). Prior to the tests, the initial geometric imperfections and material properties of the specimens were measured to ensure that they satisfy the relevant engineering specifications. Twelve specimens exhibited typical local buckling. The axial deformation and axial strain were analyzed, and the utilization rate of the steel strength decreases with an increase in the yield strength and width-thickness ratio. Furthermore, a close relationship was observed between the occurrence of local buckling in the flange and the web. The results also indicate that the postbuckling strength of the axially compressed HSS welded H-section stub columns with slender sections cannot be ignored. The test results were used to verify the accuracy of the FEM, which considers the initial geometric imperfections and welding residual stress. For the Q420-Q960 steel welded H-section stub columns, parametric analysis was performed using the verified FEM to evaluate the limits of the width-thickness ratio and ultimate axially compressed bearing capacity. To apply current European, American, and Chinese codes, the modification factors for the width-thickness ratio limit and ultimate bearing capacity are given.