The "mixed structures" of the sanatoriums built in the 30s in Italy

This paper reports the first results of the research aimed at the knowledge of the way of building in Italy in the '30s through the historical and technological study of existing buildings. The study concerns with the "sanatoriums" built in Sicily between the two world wars, well known by the typological and therapeutic viewpoint, but not yet by the technological one. They are an interesting example of so-called "mixed construction" where traditional techniques and testing of new materials, particularly reinforced concrete, co-exist. The building practice for ordinary buildings of the period concerned with load-bearing masonry construction, wooden roofs and reinforced concrete elements only for floors, stairs and overhangs. In public constructions (schools, hospitals, etc.), in which, due to specific use, wide lights and roofs were necessary, designers and companies tested the potentialities of reinforced concrete for the whole structure (beams, pillars, foundations, floors and roofs). The historical and constructive study of chosen buildings was carried out through non-destructive tests and surveys to define the building static scheme and draw the main technical details. Thermography was used to detect the presence of reinforced concrete columns and beams, hidden in the wall thickness, still performing load-bearing function. In the examined roofs, complex systems of reinforced concrete beams were found instead of traditional wooden trusses, together with tiled and wooden plankings. This study contributes to the rare knowledge of materials and construction techniques of the twentieth century Italian architecture, unfortunately arising at every intervention aimed at the preservation and reuse of these buildings.