Answer:
A SHAPE‑THIN cross-section may consist of several unconnected partial sections, so it is calculated in SHAPE‑THIN according to the theory of stiffening systems. SHAPE-THIN also displays a corresponding message before the calculation. The design of such cross-sections is not possible in add-on modules such as RF-/STEEL EC3 or RF-/ALUMINUM.
In most cases, however, it is assumed that the cross-section parts are connected to each other. FAQ 002389 describes how you can model this connection.
Furthermore, SHAPE‑THIN provides an option to define different materials for the individual cross-section parts. In RFEM 5 or RSTAB 8, it is also possible to assign materials for the individual cross-section parts (see Technical Article 000855).
However, these hybrid cross-sections cannot be designed in add-on modules like RF‑/STEEL EC3 or RF‑/ALUMINUM.
