How to create an omega shape profile as a thin-walled section to be calculate according with EN1993-1-3 (cold formed sections)

[GustavoSilva777]

Hi everyone,

I need to perform some structural analysis for cold formed steel sections according to Eurocode 3 (1993-1-3).

One of the profiles types I'll be using is the omega shape.

In my case the omega shape isn't exatcly as the one contained in the  know PDF "EC3_thin_walled_sections.pdf" shapecod 1007 (print below) : 

Here is an example of a section of mine : 

I was looking for other similar shapes in that pdf "EC3_thin_walled_sections.pdf" and maybe the position Sigma (1012) might work (print below) . Although the "B" member in my case is inclinated, so it doesnt make a 90º degree as the position 1012 does, I think I should be able to get very similar mechanical properties results (Area, Iy, Iz, etc).

The problem is that I can't find this type of section in the "SadePro" database. I  only find the S and S+ shapes, not the SL as intended.

Does anybody know where I can find the sections with the shapecode 1012 in the Robot databases? Or did anyone already tried to make something like this in Robot? 

Anyone of you know how can I correcly model this type of profile? So it can be later verifired as a thin-wall member (1993-1-3)?

Thanks alot in advance,

Best regards,

[Stephane.kapetanovic]

hi @GustavoSilva777 

It’s best to create your own worksheet to evaluate the specific aspects of the Eurocode that you wish to investigate.

You can also extrude an equivalent polyline and analyze the section’s behavior using finite element methods, particularly to study the effect of web inclination on the flanges, as well as the various warping patterns that may arise from transverse loads.

In your topic, you mention selecting a shape type similar to either 1007 or 1012. These two section types are not part of any standard catalog.

• The 1007 "hat" profiles are uncommon and rarely exceed 120 mm in size. (BARBIERI, BOUWEN MET STAAL, JORIS IDE, Macsteel, RUUKKI, ...).
• The 1012 sigma profiles are generally used as thick continuity splice plates, as 1001 and 1002 types are more cost-effective for spanning purposes.

However, their type can be used in the design if you decide to go with this kind of section.

The calculations performed are standard, conventional and in compliance with the Eurocode implemented in your current software version.

From a calculation perspective,

• 1007 sections are defined with straight webs, not inclined like in your case, and their edge stiffeners are also straight, unlike yours.
• For the 1012 section, the web does include an inclined portion, but you would need to increase its height beyond the flange width—posing the same issue for the edge stiffeners, which would effectively become flanges.

After the section properties are calculated, the design will proceed as if it were a standard section, without capturing the particularities of your geometry.

To calculate all the properties and insert the profile into the user-defined table, you can import your section as a DXF file from the Section module into a new thin-walled section.

Once computed, you'll need to manually change the shape type directly in the table and input the appropriate dimensions for the design:

For SHAPE_TYPE = 1007: H, B, P1_L, EA, RA

For SHAPE_TYPE = 1012: H, B, B_2, P1_L, P2_L, EA, RA

To edit the table, you can use the database catalog editor or an XML editor, such as Microsoft XML Notepad.

Best Regards

[GustavoSilva777]

Hi @Stephane.kapetanovic,

Thank you for the reply!

So, if I understood correctly, there is no real solution for this type of section in Robot?

Even with the 1012 section type and the appropriate modifications, Robot would not verify the section as a cold-formed one, according to EC 1993-1-3?

Besides that, I also have a question: where can I find this type of section in Robot’s databases? I know the PDF mentions it's in the Sadepro database under the name "SL", but when I opened the section database, I couldn't find it...

Thanks again for the feedback.

Best regards,

[Stephane.kapetanovic]

hi @GustavoSilva777 

So, if I understood correctly, there is no real solution for this type of section in Robot?

Even with the 1012 section type and the appropriate modifications, Robot would not verify the section as a cold-formed one, according to EC 1993-1-3?

Robot calculates all thin-walled sections listed in the table, from 1001 to 1008 and from 1010 to 1015.
Since no dedicated method exists for your specific section, the only approach is to compare it to a standard thin-walled section in order to evaluate its performance.

to quickly see if a section exists

https://forums.autodesk.com/t5/robot-structural-analysis-forum/api-sectionxmldatabasecatalog-read-al...

Best Regards.

[GustavoSilva777]

Hi @Stephane.kapetanovic,,

Thanks again!

Ok, my idea is to try to compare it to the 1007 and 1012 section type. But for the 1012 specifically I couldn't find it in the SadePro database as suggested in the autodesk PDF " EC3_thin_walled_sections.pdf"

I guess I don't have it in my directory. Can you tell me where I can download that database file? Maybe you can send me here?

Thanks alot,

Best regards,

[Stephane.kapetanovic]

voici le fichier

... mais pas de sections SL

[GustavoSilva777]

Hi @Stephane.kapetanovic,

I've loaded it, and it's the same as mine... unfortunately, it doesn't include the 1012 section type (SL). I guess it might be a misunderstanding in the PDF.

But thanks anyway.

Best regards,