Vertical Seismic Load Analysis of the Cantilevers in Lira-Sapr

Hi everyone,We have a structure having 3.5m cantilevers all around the floor.My question is how can we consider dynamic loads on cantilevers in design model. I need a guide to implement this load into design model step by step.Some sources advises to use "Weight of dynamic plate loading" which is in "Loads on plates"Thanks in advancedTuran