In Ram Concept the loads can be uniform or sloped, but they are always linearly acting so there is no special way of applying passive pressure. Similarly, our springs are linear, so we can't exactly simulate friction, but your equation above is a reasonable…

I assumed you were performing a 'Normal' analysis, not a Lateral Self Equilibrium analysis . Lateral SE is not appropriate here. Even in a normal analysis, the structure is very flimsy when supported on tall columns (and instable if the columns are…

The program creates a special design rule set called Soil Bearing Design for the purpose of showing max soil bearing pressure. Like any other design rule, it derives demands from one or more load combinations. By default the Soil Bearing rule uses the…

I would design it all as a single mat/raft with thickened areas under the columns (if you need them - make sure you check punching shear). Model the column and wall foundation loads as loads on the slab. And model the hydrostatic uplift as a uniform load…

Hi Alex, Here's my understanding of the situation: There's about 300psf hydrostatic uplift on the slab, which is fairly constant (and much greater than the slab dead and live load) The total column and wall loads far exceed the total hydrostatic…

Yes, unless you have altered the sign convention (Criteria - sign), then the negative pressure is tension uplift. Ram Concept's soil area springs are compression-only, but the iterative no-tension analysis is controlled by 1. The combinations need to…