RSA and SAP analysis

[bogdan_babii]

I'm a student at civil engineering in my last year. I've modelled a structure both in SAP and RSA. The structure is very simple: 2x4.5 spans and 5x5 bays reinforced concrete frame structure, Gf+1Fl. The fundamental period of vibration in RSA is 0.31 and in SAP is 0.193. Can you help with some advice why this difference is present? Maybe some papers or any direction of how I should approach the problem to come up with a good conclusion.
Thank You very much!

[Mochilo]

I had some problems when computing frame fundamental periods with RSA. I think it was because of the automatic meshing. Try to divide your frame elements (bars) manually.