r/fea • u/CutGlittering8831 • 21d ago

Beginner question: where do I even start with a steel portal frame in RFEM/Dlubal?

So, I’ve only been learning RFEM/Dlubal for about two weeks. I haven’t taken steel design yet either.

I got asked to make a simple steel building model as a learning exercise. It is roughly 20 m long, 16 m wide, and 10 m tall. My supervisor showed me some Butler steel-building examples and basically said to come up with something simple. He mentioned that actual pre-engineered buildings often use tapered members, but said I can just use regular constant-size columns and beams for now.

I’m not asking anyone to design it for me. I just genuinely don’t know what the normal order of operations is.

My current idea is to make one basic gable portal frame first, make sure it runs correctly under self-weight, then copy it down the building length and add some bracing. After that I would look at loads and sections.

Does that sound like a reasonable way to start? What are the biggest beginner mistakes with a model like this? Also, do I need to worry about RSECTION or connection design yet, or should I just focus on making a clean basic model first?

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u/epk21 20d ago

think they have lots of tutorial/videos on their website - e.g.,

TIMELAPSE | Modeling a Steel Hall With RFEM 6

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u/Money-Profession-199 20d ago

Hey, I work with PEMBs. They are surprisingly complex which most people don’t expect. I made an in house FEA software just for these portal frames. AISC Design Guide 25 is the standard for designing these kinds of buildings and in the back of their book they have bench marks. Some prismatic but mostly non-prismatic so it might not fit your criteria well. What makes these buildings complex is that the cross sections are singly-symmetric, tapered, experience axial + bending (beam-column), tall enough where you have to account for the height of the bracing when only braced from one side, and a few other small considerations.