Cold-Formed
This tab allows you to analyze cold-formed sections according to EN 1993-1-3 [3]. The check boxes are only accessible if the RF-/STEEL Cold-Formed Sections module extension is licensed.
If you want RF-/STEEL EC3 to Perform design for cold-formed cross-sections acc. to EN 1993-1-3, select the corresponding check box. Then the other sections of this tab become accessible as well.
An example of the design of a cold-formed C-section is presented in a technical article that you can find in the Knowledge Base on our website. There is also a webinar in which the design of cold-formed sections according to EN 1993-1-3 is discussed.
The design according to EN 1993-1-3 covers sections that are "cold-formed". These are cold-rolled steel products made of thin-walled sheet metal that has been cold-formed by roll-forming or bending methods. Typical cross-section shapes of cold-formed sections are shown in [3] Figure 1.1. The cross-section information in the program also includes the longitudinal stiffenings of the sections and thus the respective buckling panels.
The design of cold-formed sections is described in detail in the [3] standard.
The cross-section library contains various series of C, U, L, and Z-sections that are automatically recognized as "cold-formed" with the corresponding buckling panels and stiffeners. These sections can be filtered according to the Cross-section shape.
For the series mentioned above, it is also possible to design parametrized cross-sections.
They can be defined using the [Parametric Input] button.
Furthermore, it is possible to design cross-sections that were calculated in SHAPE-THIN 9 with the corresponding buckling panel and stiffener definitions according to EN 1993-1-3.
Cold-formed circular and rectangular sections are not part of the EN 1993-1-3 standard.
All cross-sections of the design case that do not fulfill the "cold-formed" criterion are analyzed according to EN 1993-1-1 [1].
If the Perform stability design acc. to 6.2.5(2) if possible check box is selected, the stability analysis for bending and axial compression force is performed according to the following interaction relation:
where
This alternative mentioned in [3] 6.2.5 (2) replaces a structural component calculation according to the second-order analysis as per EN 1993-1-1 with the effective cross-sections according to [3] 5.5. For biaxial bending, however, a calculation of structural components as per [3] 6.2.5 (1) according to the second-order analysis is required in order to determine the interaction between axial force and bending moment. This has to be taken into account when selecting load cases and combinations in Window 1.1 General Data.
The Web without stiffening at supports acc. to Tab. 6.1 check box affects the value of the shear buckling strength fbv. According to [3] 6.1.5, starting from a web slenderness ratio of 1.4, the geometrical conditions in the form of stiffeners on the support have to be considered accordingly so that web deformations (local buckling) are avoided and the support forces are absorbed.
With the Design of local transverse forces acc. to 6.1.7 if possible check box, you can control whether the program also analyzes local failure modes in the web that occur due to support forces or local transverse forces through the flange into the web. [3] 6.1.7 describes different cases and design conditions that have to be fulfilled for the web loading. The boundary conditions, such as the length of the stiff bearing, can be defined in Window 1.14 Local Transverse Forces (see Chapter 2.14).
Literature