FAQ 004948 EN-US
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In the default setting, the cross-section class for each member and load case is determined automatically in the design modules. In the input window of the cross sections, however, the user can also specify the cross-section class manually, for example if local buckling is excluded by the design.
SHAPE-THIN determines the effective cross-sections according to EN 1993-1-3 and EN 1993-1-5 for cold-formed sections. You can optionally check the geometric conditions for the applicability of the standard specified in EN 1993‑1‑3, Section 5.2.
The effects of local plate buckling are considered according to the method of reduced widths and the possible buckling of stiffeners (instability) is considered for stiffened sections according to EN 1993-1-3, Section 5.5.
As an option, you can perform an iterative calculation to optimize the effective cross-section.
You can display the effective cross-sections graphically.
Read more about designing cold-formed sections with SHAPE-THIN and RF-/STEEL Cold-Formed Sections in this technical article: Design of a Thin-Walled, Cold-Formed C-Section According to EN 1993-1-3.
- Why is there no stability analysis displayed in the results despite the activation of the stability analysis in RF‑/STEEL EC3?
- How can I perform the stability analysis in RF‑/STEEL EC3 for a flat bar supported on edges, such as 100/5? Although the cross-section is rotated by 90° in RFEM/RSTAB, it is displayed as lying flat in RF‑/STEEL EC3.
- In RF‑/STEEL EC3, is the "Elastic design (also for Class 1 and Class 2 cross-sections)" option under "Details → Ultimate Limit State" considered for a stability analysis when activated?
- In the RF‑/STEEL EC3 add-on module, I obtain an extremely high design ratio for a member in the case of "Biaxial bending, shear and axial force." Although the axial force is relatively high, the design ratio seems to be unrealistic. What is the reason?
- I have just noticed that the STEEL EC3 add-on module also calculates with γM0 = 1.0 when designing a tension member, although it should actually be γM2 = 1.25. How can I perform the design correctly?
- Why do I get a design ratio for the cross-section check according to 184.108.40.206 in the STEEL EC3 add-on module? Why is a * added to Equation (6.36)?
- I design a frame with a taper (docked cross-section). STEEL EC3 classifies the taper in Cross-Section Class 3. Accordingly, the elastic resistances are taken into account, which is very unfavorable. According to the standard, the taper should be categorized in Class 1, and thus the plastic reserve should also be usable.
I design an eccentrically modeled wall beam in RF‑/STEEL Warping Torsion, which is loaded transversely with a distributed load. While the bending moments in the main program result in zero at the member start and member end due to the hinges, the RF‑/STEEL Warping Torsion add-on module displays moments at these locations, which incorrectly reduces the span moment.
How do I get the boundary moments equal to zero at this point?
- I get the error message "Entry in the 'Beam spacing' box is not within the allowable range." What can I do?
- I cannot find any reason why no plastic design is performed for a class 1 cross-section. Normally, you have to select the check box for the elastic design.