SGAI S.r.l. did revision of the detailed design, additional design during construction phase, maintenance plan and As Built draft. These phases include enlargement of existing sections and realization of new parts. SGAI S.r.l. designed 9 long viaducts, for example: Tanagro e Petroso bridges, with orthotropic slab (114 m span), Costa Incoronata Viaduct in concrete and steel (max 115 m span), S.Onofrio 1, Lontrano, Murusella e Tanagro Viaduct in concrete and steel (max 115 m span an 100 m height). All viaducts are made of weathering steel and a collaborating slab. Steel structural works are box girder, with constant (S. Onofrio 1, Lontrano, Murusella, Tanagro Viaducts) or variable section (Costa Crowned Viaduct). For viaducts with high spans value (Tanagro and Petroso bridges) are used solutions in steel and concrete and orthotropic slab. In this projet SGAI S.r.l. design some works that can be summarized in the following sectors: geotechnical, civil engineering, structural, roads, drainage and hydraulic regulation, roads lighting systems.