Calculation of effective sections for cold-formed sections

[PedroSoares]

Hello everyone.

I am using RSECTION to compare the values of the effective section of a cold-formed profile with the values presented on the profile´s catalog. The most important values are presented in the image bellow.

After the calculation, I went to check the values and noticed that some of the values (mainly the values related to the aplication of a negative bending moment in the z axis in RSECTION) are much lower tha the ones presented in the catalog (see images bellow).

This hapens because, when following the Eurocodes, when a negative moment is aplied, the lower flange has a lower resistance and, therefore, its thickness is reduced (see image bellow)

Because the values on the catalog seem to be verified using experimental methods, this reduction in thickness does not hapen.

My question is: is there a way to stop RSECTION from performing the section reduction? Can I add a support to the lower flange to prevent this?

(Note: the y axis in the catalog values corresponds to the z axis in the RSECTION model and vice versa.)

Best regards,

Pedro

[sandy.matula]

Hi PedroSoares,

thanks for your message!

To analyse the problem more precisely, the model file would be very helpful:

Click on File → Save as and choose the following settings to reduce the file size:

Then upload the file here (e.g. *.rf6, *.rs9) – this way, the community can also contribute to the solution.

Prefer not to share the file publicly? No problem – send it to me via direct message: click on my profile picture or user name → Message.

Best regards
Sandy Matula

[sandy.matula]

Many thanks for your model file

The check for distortional buckling of sections is always performed automatically in the calculation process. It cannot be deactivated.

I hope this helps you move forward. If you have any questions, feel free to reach out.
I’ll be happy to look into it with you

Best regards
Sandy Matula