The drawing of the San Luca portico in Bologna

This contribution synthetically presents the results of the first stage of a research finalized to look into the architectural individuality of San Luca portico in Bologna; an extraordinary extraurban arcade - system, a strong sign of the urban development of the city in the seventeenth and eighteenth century stable in the urban image of Bologna. The main aim of this work is to produce a complete and systematic graphic documentation of this arcade-system that, despite of its local fame, lacks of an in-depth study; moreover, it intends to investigate how the urban space around this system has been modified and reshaped; finally, how an important portion of Bologna, such the one sourrounding San Luca, took form and developed. Considering the inner complexity of this arcade-system and its 3.300 mt length, an approach based on separated representations of figures and forms has been rejected from the beginning. Such an approach would lead to a fragmented and incomplete interpretation. The existing studies about the portico are mainly historic, or somehow circumstantial to some traits of the arcades. They allow only a partial reading which does not permit to completely understand its identity. Vice versa, this part of the town has been considered as a whole, a unique architectonic object, whose representation has been coded by means of a specifically designed graphic language. Moreover, the secondary aim of the work has been outlined: to look into the urban shape settled and led by the portico. More generally, how an important urban feature of Bologna was formed and developed. The evocative historical views, which decorate the portico and its urban contest, witness an urban landscape that drastically changed because of the building of the portico, with particular reference to these last years; nevertheless, while the plan tract is almost entirely comprised in the urban texture, the one on the hill represents a marked and distinct sign which hails people coming to Bologna from north and from west. Hence, the choice to deal with a portion of the city as single architectural object, whose representation must be expressed in a new graphic language, necessarily reformulated with the specific characters of this case. The strength of the representation is to let stand out and make clear, in a synthetic and immediate way, otherwise hidden relations, and also to relate its history and events with great efficacy. The whole surveying is based both on photographic, archivistic and historical documentations and on direct and indirect measurements. Mappings have been carried out by students at the second year of the Faculty of Engineering – University of Bologna. The strict procedural constraints and the explicit graphical methodology has allowed to merge every single mapping in one comprehensive document. Its graphic language has been specifically designed coding iconographic signs. The whole fronts have been surveyinged with direct methods, manual and at sight ones, integrated with photographic correction methods according to the use; sections have been executed with direct measuring methods and the same with reference to the surveying of the ground floor. The result is a long “drawing” about 25 meters in length (if printed in scale 1:200), a “ribbon” where the drawings of the parts are reset through the connection of the plant of the portico, from the longitudinal section and from the view of the urban fronts. Therefore the composition in a single synthetic picture displayed a double meaning, either as an instrument of reading and analising or as an instrument of planning.