The paper presents research into the advanced stability analysis of stiffeners in structural steel joints. Stiffeners are investigated by the component-based finite element method (CBFEM). To avoid local buckling of slender plates in CBFEM a design procedure is proposed and verified on the research finite element model (RFEM). RFEM is studied by material and geometrical nonlinear finite element analysis with imperfections. It is proposed to use a combination of material nonlinear analysis without imperfections with buckling analysis in CBFEM.
The verification is shown on an example of a web stiffener in the welded portal frame joint. The stiffener is studied by numerical analysis, resistances and critical loads are determined in RFEM and CBFEM and results are compared. A numerical study illustrates the effect of the stiffener’s thickness on the joint’s resistance. A mesh sensitivity study is covered and the optimal number of elements along the stiffener’s width is recommended.