Include lateral mass in the mass source option in Etabs

[geo321]

Hi,

In the mass source in the Etabs software, there is the option in the mass source option to include lateral mass. In their documentation, CSI indicates that "assigned translational mass in the global X and Y and assigned rotational mass moment of inertias about the global Z axis are considered in the analysis" if include lateral mass is checked.
I don't understand what does it mean practically and in which cases should it be checked or not ; can someone shed some light please ?

 

[milkshakelake]

I'm not 100% sure but it sounds like it would consider any loads you applied in the X or Y direction. Usually, the mass considered is only applied in the Z direction (gravity).

You can test this out. Try applying some X/Y loads and see if it affects the lateral shear.

I kind of struggle to think of any case where this would really apply. Maybe it's more suited to components rather than an entire building design.

 

[geo321]

actually i have just tried it bass the base shear isn't affected; i guess if it was about forces, they would have written forces but not masses; i am not able to understand this translational mass what do they mean by it and an example of it.