Local buckling behavior of welded π-shaped compression stub columns

The local buckling behaviors of welded π-shaped stub columns were investigated experimentally and numerically in this study. Nine welded π-shaped columns made from Q345 steel with different width-to-thickness ratios were tested under axial compression. The material properties, initial geometric imperfections and welding residual stress distribution of specimens were measured. Results from the tests, including the strengths, the load-deformation responses, and the failure modes were presented. The strengths determined by tests were compared with the design strengths predicted by the current steel design specifications. The experimental studies were complemented by the numerical investigations, in which the finite element models were initially verified against the test results and subsequently used for parametric studies covering a wide range of cross-sections. The modifications on the Bleich formulas were derived to calculate the buckling coefficient of π-shaped section. Based on the experimental and parametric analyses, formula for direct strength method (DSM) was proposed to predict the compressive strengths of welded π-shaped stub columns, which offered reasonable predictions.