I am working on a two story steel building and am experiencing issues with the beam optimization. RAM is currently using a loading combination for some beams, displayed below, that is not the maximum loading so the beams are designed too small. Instead of using 1.2DL + 1.6LL RAM is designing based on 1.4DL for some beams even though it shows 1.2DL +1.6LL as a larger loading. This is only for some beams, not for all. How can we make it so RAM uses the maximum loading combination for all beams for optimization?
The program should be considering both of those load combinations. Furthermore it is checking bending, shear, and deflection so there are 6 (or more) possible controlling conditions for each beam. If your beams are really being underdesigned I would need to see the model and confirm your version.
Sarah and I are working on this project together. As of right now, we only have dead and live loads on the building. When we look at the beam design results, all of them have the 1.2D+1.6L as the highest load combo, but many of them are using the smaller 1.4D as the controlling load combo, so we assume that these beams are only being designed to withstand the dead loads and not the live loads acting on them. Also, regardless of flexure, shear, deflection, etc., shouldn't it be using 1.2D+1.6L for every beam since we only have dead and live loads?
Can you share the file, or at least the output?
I uploaded it. I think it worked but I am not sure (I'm new to this forum). The file name is "CAST Ram Model 2-23-2021.rss". Let me know if you can open it.
I see your file, but it's not complete, there is no story data defined. I assigned 1 story using layout 2nd and ran it in v17.02.
Here is partial output for Beam 62.
The beam is composite and not shored, so it has a different composite capacity (considering all loads) and pre-composite capacity (using only construction loads). In this case the pre-composite demand/capacity ratio is 37.5/46.9=0.80 while the post-composite bending DCR is 68.6/103.66=0.66 so the pre-composite check controls.
For more please refer to: https://communities.bentley.com/products/ram-staad/w/structural_analysis_and_design__wiki/2053/ram-steel-beams-faq