Models of urban development: examples in Bologna

The research identifies and describes the evolution rules used for the maintenance and regeneration of urban spaces, searching in the city growth patterns emerged in the course of its historical development and characterized by the transformation processes that develop on socio-economic forces that do not conform to urban “pre-defined” planning policies. These researches are of great interest for the parts of territory created by recent developments of the city which need a redesign aimed at the regeneration of places and redefinition of territorial systems, with the recovery of a sense of membership and community living. Therefore the study of some historical "ways" of re-definition of the urban fabric of Bologna is of great interest. The study of the implementation of the Portico of Banchi in Piazza Maggiore, a masterpiece of Vignola in the second half of the sixteenth century, shows an early example of urban intervention of completion and re-building, defining a mode of intervention that Bologna will adopt and use as a strategy of intervention for the next four hundred years. The study of parallel evolution of the Portico of Banchi, of the plain part of the Portico of San Luca and Alemanni, shows the general development strategy of the city by the overlap of new items to the existing building and offers significant incentives to conceive new ideas for the present. These modes of development let entire urban sectors maintain a specific identity in their evolution. This identity has been lost in successive urban plans which didn’t care about historical developmental characters, violating the rules of expansion of the historic town and obstructing the continuity and the interweaving of new buildings with existing ones