New Dlubal Add-on Modules for Steel Design

RF-/STEEL Warping Torsion and RF-/JOINTS Steel - SIKLA


Two new add-on modules have been released with the latest customer version of RFEM and RSTAB.

RF-/STEEL Warping Torsion is a module extension of RF‑/STEEL EC3. It performs warping torsion analysis of members according to the second‑order theory with 7 degrees of freedom and application of imperfections with regard to mode shapes.

The RF-/JOINTS Steel - SIKLA add-on module designs connections of fastening system produced by the Sikla manufacturer (brackets of type AK and TKO as well as end plates of type STA, WBD, and WD).

RF-/STEEL Warping Torsion

Since RF‑/STEEL Warping Torsion is fully integrated in RF‑/STEEL EC3, the data is entered in the same way as for the usual design in RF‑/STEEL EC3. The module extension includes a separate solver considering 7 deformation directions (ux, uy, uz, φx, φy, φz, ω) or 8 internal forces (N, Vu, Vv, Mt,pri, Mt,sec, Mu, Mv, Mω).

It is possible to calculate all thin‑walled steel cross‑sections. The program performs nonlinear design according to the second-order analysis. The results include critical load factors and buckling mode shapes that can be visualized (including warping).


The add-on module designs the following Sikla joints.

  • Brackets of type AK and TK
  • End plates of type STA, WBD, and WD

Interaction of internal forces is performed. The module considers joint eccentricities and determined nonlinear spring constants. In addition, the connection geometry including the connected girder cross‑sections is checked automatically.