The paper presents a simplified model for simulating the elastic behaviour of cylindrical ground-supported steel silos containing granular-like material. The idea is to reproduce the elastic parameters of this silo typology through a simple three-degree-of-freedoms (3-DOFs) model. To this aim, analytical rules and equations for defining mass and stiffness of the model were defined, accounting for different service conditions, i.e., filling levels of 0%, 30%, 60%, 90%, and for different geometries, i.e., very slender, slender, boundary, intermediate squat, squat. The outcomes were evaluated firstly in terms of natural frequencies, and after in terms of horizontal (or normal) and vertical (or frictional) pressures, according to the current European code provisions. The latter were compared towards the ones obtained by overdetailed finite element models, reproducing analogous silos with the related geometries and service conditions. The obtained results are shown throughout the manuscript, offering room for improvement for the proposed simplified model, especially in a view of predicting the nonlinear behaviour of cylindrical steel silos and the most likely buckling failure modes under seismic actions.