Answer:
This is used to provide proof of longitudinal joints of welded cross-sections. Joints and other connections are not designed. The weld design is only performed for the welded cross-sections of the cross-section library.
It is important that the thickness of the weld is specified in the cross-section definition (see the image). The fillet welds of SHAPE‑THIN cross-sections cannot be designed in RF‑/STEEL EC3. However, these can be designed in SHAPE‑THIN.
