Numerical investigation of high-strength built-up box columns

As high-strength steel box columns are usually fabricated by welding steel plates together, the welding process inevitably introduces residual stress and geometric imperfections and may affect their compressive strength. A detailed numerical investigation was conducted to study the behaviour of high-strength steel built-up box columns under compression. The welding processes were first simulated by a three-dimensional fully coupled thermal-mechanical modelling procedure using the general-propose finite-element package Abaqus. The residual stress distributions in the columns generated by different welding processes were determined. The column strengths under compression were then modelled by incorporating both the computed residual stress and the initial geometrical imperfections of the column as predefined input fields. Furthermore, the effects of different welding processes and heat treatment methods on built-up box column strength were investigated and discussed.