Indagini per la conoscenza e la tutela dell'architettura militare storica. Il fronte occidentale delle fortificazioni di Cagliari (Sardegna, Italia)

This contribution shows some results of a multidisciplinary survey, which includes the integration of architectural surveying methods and geophysical methods. The operative procedure is applied in the portion of the ancient walls between the bastion of Santa Croce and the fourteenth-century Elephant Tower, in the city of Cagliari, Italy. The sector under study consists of 1) the wall curtain of Santa Chiara designed in 1575 by the engineer Giorgio Paleari and 2) the de Cardona wall curtain, a work commissioned by the Viceroy in the 30s of the same century. The archival documents offer precise indications on the extent of the collapses and the reconstructions/expansions that took place in that period, so facilitating a recognition of the events that took place. The work of the sixteenth century -brought to completion by the same Giorgio Paleari in the years 1576-1578- advances the line of defense with respect to the border of medieval matrix by means of a robust embankment, and incorporates two of the fifteenth-century towers described in the drawings of the military technicians of the time. In the eighteenth century the front was completed by the construction of a lowered embankment near the southern side of the bastion of Santa Croce and the curtain of Santa Chiara, and more recently it has been improved by means of several restorations and consolidations that changed the profile of the parapet –in the origin it was inclined - and the static balance of the constructive system, also through the use of reinforced concrete piles. The application of the survey methods and techniques used in this study provides interesting information about the current structure of the bastion system and the presence of vaulted passages functional to the military work. A new study campaign mainly based on seismic geophysical techniques is proposed.