A new fly ash silo is built with a construction of reinforced concrete (height = 55 m, diameter = 24 m) as part of the new power plant at the E.ON site at the Maasvlakte Rotterdam, Netherlands. The total weight of the silo is 400 MN when filled with fly ash. The silo is constructed on a 2.5 m thick concrete base slab and is founded on 59 large diameter bored piles (Ø 1.5 m) with a length of 32 m. The soil investigation revealed a mainly sand profile with a clay layer at 10 m below pile tip level, which varies in presence and thickness. The heterogeneity of the subsoil may result in differential settlements, which will lead to higher stresses in the construction depending on the stiffness of the construction. Detailed information on the heterogeneity of the subsoil, the stiffness of the structure and the pile behavior is necessary to analyze the settlement behavior and the forces in one interaction model, where all components with its properties are incorporated. A realistic interaction analysis is performed in 3D with the finite element program PLAXIS 3D. The advantages of this approach in comparison to the general accepted design approaches with a conventional elastic support model are defined.