Contribution to the Knowledge of Apennine Rural Architecture. Technical Culture in the Abandoned Historical Cillages of the Upper Santerno valley (Italy)

The regeneration of rural architectural heritage, at the centre of the debate on the depopulation of internal areas, often falls into simplistic interpretations, leading to interventions that alter cultural values and contents. In Italy, this phenomenon also affects the Santerno valley, in the Tuscan-Romagnolo Apennines. Dotted with abandoned rural settlements and traces of old castles, this valley preserves evidence of a rural settlement system consolidated since the Middle Ages, during which the Florentine Republic and the Ubaldini family clashed between the 13th-15th centuries. The abandon conditions of buildings and slope agriculture threaten the survival of this widespread heritage. An ongoing research conducted by the University of Architecture and the Superintendence of Florence has the objective of understanding the cultural and technological contents of the Piagnole village, a high-altitude settlement made up of a few buildings and a chapel made of wood and stone, whose origins are connected to one of the Ubaldini castles. Starting from architectural surveys, typological methods were used to read the building, analysing techniques and characteristics of structures and architectural elements, observing any systematic distribution in plan and elevation. Furthermore, in-depth investigations on the 50 openings and squared blocks, clear evidence of the technological culture that created them, recorded their characteristics (position, materials, dimensions, geometries, etc.). Some recurring types of these architectural elements emerged whose distribution focused the evolutionary framework of the settlement. Furthermore, the rich presence of ancient units of measurement (in the individual elements and in the buildings) in use in Florence, Imola and Bologna, highlighted their articulated and combined use over time, connected to the culture of the authors who took turns. The chrono-typological investigation therefore proved to be crucial in understanding the architectural remains, demonstrating how this study can also support the expansion of knowledge of other numerous villages of the Santerno valley.