1.1 Scope of EN 1993 4 1 (1) prEN 1993 4 1 provides rules for the structural design of steel silos of circular or rectangular plan-form, being free-standing (on ground) or supported on a structural framework (elevated). (2) prEN 1993 4 1 is applicable to silos constructed from isotropic rolled plates that are stiffened or unstiffened, from corrugated sheeting that is stiffened or unstiffened and from flat or corrugated plates assembled into box structures of different geometries. It applies to vertical walls, hoppers, roof structures, transition junctions and support structures. (3) prEN 1993 4 1 does not apply to storage vessels for silage and haylage, or to the storage of materials that are not free-flowing (see EN 1991 4). This Part 4-1 also does not cover: - resistance to fire; - cylindrical silos with internal subdivisions; - internal structures within a single silo (except for internal ties, as defined in 12.5); - silos with capacity less than 100 kN (10 tonnes); - hopper
