Numerical study on the local buckling of 420MPA steel equal angle coloums under axial compression

High strength steel sections have been increasingly used in buildings and bridges, and Q420 steel angles with a nominal yield strength of 420MPa have also been widely used in many steel structures, especially in transmission towers and long span trusses. Compared to the conventional hot-rolled steel angles with normal strengths, local buckling is more critical for high strength steel angles. Based on a series of axial compression tests of 15 stocky equal angle columns made of 420MPa steel, a finite element model is developed to analyze the local buckling behavior of high strength steel equal angle columns under axial compression. By comparing the finite element analysis (FEA) results with the test results, it has been verified that the model can accurately simulate the axial buckling behavior of high strength steel equal angle columns based on measured initial geometric imperfections and residual stresses. A finite element parametric study is also conducted to study the influences of a range of parameters on the local buckling strength of these columns, including the initial geometric imperfections, the residual stresses and the width-to-thickness ratios of the angle leg.