Dynamic Loads and Isolated Pads

[AJA14]

Hi Guys. It's been quite some time since my last post. Anyways, I hope to get your assistance in this matter. 

I have equipment that will be inducing dynamic loads on the foundation. I have two issues to consider. 

1- Application of dynamic loads. For this I will use time history analysis. The force is in the order of magnitude of 20 KN and the frequency is in the range of 3 Hz. The mass is around 1100 kg. I beleive these should be enough but I do have a concern. The machine is tied in three different location to the ground footing. 

Should I tie all these nodes to a central master node and apply the dynamic load to that node?

2- It is requested to isolate the footing from the grade slab. We will be providing recessed grade slab, provide neoprene or flexel around the recess, and place the machine plinth. How would one model such a thing (if possible) in robot. I hope to have clarified enough. See attachment for image. 

Thanks.