ASSESS to reduce the risk of school buildings at regional level

In a seismic territory, one of the concerns of the public administrators is to guarantee people safety in case of earthquake, mainly in public facilities and in particular in school buildings. Public administrations are facing a complex problem and they need to know the level of risk and the criticalities, together with the required countermeasures and their costs, in order to define a rational and effective strategy for the mitigation of seismic risk, and consequently better allocate the resources (money and time). This problem was addressed in the ASSESS (Analysis of the Seismic ScEnarios of the School buildings for a definition of retrofitting priorities for Seismic risk reduction) project, aimed at knowing for preventive purposes the seismic risk of about 1000 school buildings of the Friuli Venezia Giulia region (north-eastern Italy). During the project, the evaluation of people safety was approached with holistic and interdisciplinary methodologies, and with multi-level studies (Figure 1). In particular, geological and geophysical studies together with vulnerability evaluations were carried out in correspondence of the school buildings. For each school a geological-technical map was developed, on which the geomorphological and hydrogeological features are represented, as these aspects can be considered potential seismic amplifiers. Furthermore, geophysical investigations were carried out in order to assess the velocity profiles to be used for evaluating the local amplification, through 1D modelling. The vulnerability assessment was done in a different way based on the level of investigation: the first level was based on a statistical approach, while a specific methodology, named VISUS, has been applied in the second level: the method, developed during the project, is based on rapid visual screening that permits the identification of weakness or critical effects in the seismic behaviour. Moreover, the vulnerability related to non-structural elements and of the egress system is provided. The ASSESS project implied the definition of decision-making supports in the form of synthesis indicators (Figure 2). In particular, a performance structural class was assigned to each school building, based on the ratio between the capacity and the demand of the structure. The membership to each class is defined, graphically, in analogy to the energy efficiency classes.Furthermore, globally considering safety, five main issues have been identified in order to take into account all the elements that can cause deaths or injuries: site, global structural, local structural, non-structural, and functional weaknesses. The results are synthesized within an “intervention requirement rose”, where the presence of one or more “petals” implies the presence of potential criticalities, while a rose without “petals” implies that the goal of “people safety” has been reached. The data in the “intervention requirement rose” are again synthesized in a single indicator: the “ASSESS safety star”, that provides a global seismic judgment of the school. Finally, it is important to remark that the decision-making support tools defined for public administrators permit to better address the resources for a more effective definition of a strategy aimed at seismic risk mitigation at a territorial scale.