Grain storage silos by Frame S.p.A., Bologna, Italy, are made of corrugated sheet steel panels reinforced with sturdy outside stiffeners of profiled sheet steel. High-resistance steel is used with Sendzimir galvanizing, 350 g/m2. The roof is made of trapezoidal elements of galvanized, ribbed sheet steel to support heavy loads. The parts are assembled with high-strength bolts guaranteed against corrosion by a Dacromet coating. Special elastoplastic materials and PVC washers ensure a perfect seal between panels and bolts.