Axiological strategies in the old towns seismic vulnerability mitigation planning

Vulnerability is a big issue for several small inland urban centres, characterized by settlement complexity, structural fragility, typological and formal inertia, and a low population density, most of which are exposed to the risk of depopulation. In the climate of the centre-northern part of Italy, and in the context of the recent concentration of a high number of earthquakes in that area, seismic vulnerability can become the determinant cause of the final abandonment of a small town. In some Italian regions, as well as in Emilia Romagna, municipalities are strongly committed in the implementation of effective seismic vulnerability reduction policies based on the Emergency Limit Condition, which has become a basic point of reference for ordinary land planning. This study proposes an approach to seismic vulnerability mitigation based on valuation planning for implementation within the general planning framework of the Faentina Union, a group of five small towns located in the south-western part of the Province of Ravenna, Italy. This approach consists of three main stages: Knowledge, concerning the typological, constructive, and technological descriptions of the buildings, specifically focused on their degree of vulnerability; interpretation, concerning the analysis of the urban fabric and its topographic arrangement with the aim of outlining a range of hypotheses with respect to damage in case of a prospective earthquake; planning, concerning the identification of the courses of action intended to meaningfully reduce the vulnerability of the buildings as first and of the whole old town as second. This stage includes a cost modelling tool aimed at defining the trade-off between the extension and the intensity of the vulnerability reduction works, given the budget. The main concern of this study is to provide the decision makers with a valuation-planning tool able to outline a wide range of scenarios differently combining the amount of the budget, the degree of safety and the completeness of the interventions. Such a flexible tool matches the need of implementing strategic policies able to combine the prospects of different stakeholders and stockholders, the former concerned about safety, the latter concerned about cost control.