According to ASCE-07-22 [1], balanced and unbalanced loads shall be analyzed separately. 


  • Balanced Snow Load for Main Frame and Purlin Design: 





  • Unbalanced Snow Load

Winds from all directions shall be accounted for when establishing unbalanced loads.

Moreover, according to MBMA [2] while designing purlins, all purlins shall be checked under the minimum snow load. 


Accordingly, MkaPEB includes unbalanced snow-load cases in its analysis.


For Main Frame Design: 



For Purlin Design:

This loading is similar to the primary member design loading; however, the applied snow load for Secondary Member Design Loading is nowhere taken less than the minimum snow load (Pm).



References:

[1] American Society of Civil Engineers. "Minimum design loads and associated criteria for buildings and other structures." American Society of Civil Engineers, 2022.

[2] Metal Building Systems Manual, 2024 Edition.