Compressive strength of girth-welded stainless steel circular hollow section members: Stub columns

• Compressive strength of girth-welded stainless steel CHS stub columns was examined.
• In small and medium shells, the influence of the girth weld is insignificant.
• The influence becomes more significant with increasing the D/t ratio in large shells.
• Weld-induced imperfections should be considered in the compression behavior.

In recent years, stainless steel circular hollow section members have gained more widespread usage as load bearing constituents in construction due to their combination of corrosion resistance, aesthetic appearance and structural efficiency. This paper investigated the compressive strength of girth-welded stainless steel circular hollow section stub columns by numerical method. At first, finite element simulation of the girth welding process was carried out to obtain the weld-induced imperfections such as residual stresses and deformations employing sequentially coupled three-dimensional thermo-mechanical finite element formulation. Then, nonlinear finite element analysis in which the failure mode, the ultimate load-carrying capacity and the full load-displacement response of the girth-welded circular hollow section stub columns were explored taking the residual stresses and distortions together with the initial global geometric imperfections into consideration was conducted. Seven finite element models with different diameter-to-thickness ratios were developed in order to examine the effects that the diameter-to-thickness ratio has on the compressive strength. Results have shown that the weld-induced imperfections should be taken into account in accurate assessment of the compression behavior of girth-welded stainless steel CHS stub columns.