Dear Peter 

1.Could you please elaborate a bit more? I am  confused...In acceleration time history data(tabular)-->I used time steps 0.01 for my harmonic loading....In analysis settings,i set initial and max time step equal to what?? is written in the manual that it should no more than than 1/(20*f)-->what is f in here? I know that i should do modal analysis, but which natural frequency to consider? As I have to do numerous sensitivity analysis, small time steps will not be efficient....could you please help me to choose the best integration time step?

2. Is the integration step size(time step in transient structural analysis setting) dependant upon the load step size in acceleration time history tabular data?

It is worth mentioning that my loading is of harmonic type(0.005g,0.333Hz)....I have attached my slope geometry here for you..


Many Thanks