Different Force Member between Robot Structural and SAP2000

[fachrihaidar]

I modeled some steel truss bridge in RSAP and SAP2000,
first, i dont do modal analysis then the result is good, the difference is small and acceptable
but after i set Load Mass Conversion, Run Modal Analysis, Spectral Analysis, the difference is growing bigger until 200%. its like the load case that i define to conversion mass has been doubled the load, cmiiw.

is my analysis and modelling wrong? here is my model

[Simau]

Hi @fachrihaidar 

You may check if you get the same values for these results: