As noted in the subject title, I'm having issues with getting the hat channel members (purlins) to pass in my 3D model. The members pass if I do a bending check by hand using the same gravity load and section modulus shown in the model (Sy=Iy/c). As you can see I assigned one of the purlins to be a 1"x1-14ga tube steel member to check and see if it would pass. I picked this section due to it having similar section properties as the hat channel except it is a closed shape. Any advice on how to analyze the hat channels in STAAD so that they are only seeing axial bending from the gravity/uplift loading would be greatly appreciated. Also, please address any other errors you may notice in my model.
P.S. I did reference Section F.1 of the Steel Manual to check and see the failure mode that the hat channel was under, but I didn't get much context from the section. Also, the actual building will be 100' long and have 26 frames, I attached only a 3 frame section for simplicity. Thank you!
100x (1.5' & 3' Chord Spacing) Frame.STD
Please attach user tables DOUBLE 2.25-12GA.UPT and 1.25IN-18GA.UPT.
Sorry about that, it will not allow me to attach the UPT files. I have attached the dxf files to import into the section builder so you can make your own UPT files.
1.25in-18ga.dxf2.25in-12ga Double Tube.dxf
Try to add those UPT files into a zip archive and attach it again.
Let me know if this works.
For STAAD Ref.7z
UPT sections which have a General type are designed as an approximated I section in STAAD.Pro. STAAD does not design it as a Hat section or some other section (with the only exception for EN 1993-1-1:2005 code). Some more information can be found here: communities.bentley.com/.../612745
How do you suggest I model it in order to get the most accurate answer as possible if I cannot actually analyze the correct shape of the section itself? Is there a certain section shape I can designate the hat channel as and manually input the section properties to reflect that of the hat channel? Thank you for your help so far.
I think the most accurate method would be to analyze the hat section as you do before, but design it manually by using the reported forces of the member. The closest approximation probably would be to create an equivalent UPT channel section and design it in STAAD.Pro. Of course, this would still be an approximation and I am not sure how similar the results to actual hat section design would be.