mass source in SAP2000 v 9.0.3.

[ardelia]

Do you know something about the "mass source" for the modal analysis? I don't understand if the program calculates the z inertia by the distribuite load
thank ans sorry for my english

 

[zer]

Not sure if this helps, but check out Display->Show tables->Mass sources

 

[masomenos]

ardelia, SAP lets you define what you want to include in your mass model. If you included a -z distributed load in a particular load case, say EQUIPMENT load case for example, defining the mass source gives you the option to convert a factored load for the EQUIPMENT load case, or LIVE load case into mass. 100% of DEAD load case, 100% of EQUIPMENT load case, and 70% of LIVE case for example, could all be used to define the mass for your model

Remember that typically only DEAD load case has the self weight factor. If you define more than 1 load case to include self weight, you run the risk of double counting it.

 

[zer]

Oh, sorry, I thought you meant the inertia along the Z (vertical axis). It is probably calculated the same way for all three axes anyway.