From the rib to the cable: tradition, modernity and the contemporary in the domes to "metal structure" in Italy

This discussion is a reflection on the domes’ development as a result of the metal structure where you can identify distinct phases, taking as the geographical focus Italy, a country where the introduction of this technology suffers from the backwardness of the areas involved in its development.. The revolution of the metal cover began in the nineteenth century, when the middle class chooses the dome, symbol of ecclesiastical power and secular government, to mark the spaces called to represent the social and economic prestige achieved: the store galleries and theaters. The formal apparatus which is used for the construction of a new type of coverage, in the era of Neo-Renaissance revival, is clearly derived from classical resistant structure in sight, however, renews the traditional aspect with the introduction of a new structure, which makes the transparency and lightness of the distinctive characteristics of its image. A formal apparatus accepted by mainstream architectural era, is used together with a technological system that is innovative and introducing revolutionary techniques. The galleries in Naples and Milan and Palermo Politeama theater are the most significant episodes of metal domes made of Risorgimento age. The new technology acquired and the new possibilities offered by industrial progress could have ensured a large fortune to the theme of the big metal cover, where the cultural and social conditions had not stopped the research in this area.. Only after World War II, a period that represents the next phase of development, the debate on the metal becomes quite important. In particular, the research range from the solution of the shell of the large assembly spaces such as sports arenas, to the complete redefinition of the envelope. The new steel domes are described by the geometry of the revolution, but the architects added to the semicircular or semi-parabolic generating section, the bow section and the low polycentric. This change is formally implemented through the establishment of a technological device and new technical know-how. If the nineteenth-century used to metal dome cast iron and only for certain elements iron, with traditional static models, the desire to exploit the properties of steel and enhance the tensile behavior leads to the definition of innovative systems resistant. These experiences produce significant episodes, such as the sports hall of Genoa Sironi, the Piano’s Bull on the port of Genoa and the museum at the Lingotto in Turin.. The dome of the third generation exceeds the Euclidean geometry and is no longer described by the revolution of a section around an axis as it exploits the possibilities introduced by the numerical control machines. This new generation is not yet a reality in Italy but it is a field of experimentation for some Italian architects. The modular design gradually disappears and the help of the computer allows you to define a schedule of distinct elements which, together, allow the assembly of complex structures. A new time for the domes which take, in other forms, new variations from ancient roots.