Apply the load only at base of frame

[geoStru]

Hello everyone,

I built a 3d RC frames (2 story, 1 bayX, 1bayY) and I am trying to study the global ductility with different angles of force (pushover), different longitudinal area of bars in the columns and different weights of the building (axial force at the base of the columns)

I know that it is wrong but, if I want to study the influence of axial force only at the columns of the first floor, how can I do?

Should I use a "zerolength element" at the node of base of the column and apply the load?

[selimgunay]

You can apply the vertical gravity forces only at the first floor nodes