Plain Load Pattern vs UniformExitation

[omarzano]

Dear All,

I'd like to perform a 1D site response analysis using quad elements. Is it possible to apply the horizontal acceleration using the plain pattern command (converting the acceleration to a shear force) and the vertical acceleration using the UniformExcitation command? The recorders will return the the true nodal values or the relative ones?

The reason of this question is that I'd like to have an horizontal dashpot at the base to dissipate shear waves travelling back from the soil column but at the same time I'd like to apply a vertical acceleration.

Do you have any other clever idea?

thank you
Omar