GIS ANALYSIS OF THE SEISMIC DAMAGE ON HISTORICAL MASONRY SPIRES

Abstract. The Emilia 2012 earthquake highlighted the high vulnerability of historical masonry spires, at the top of bell towers. Indeed almost half of the spires, in the area hit by the seismic event, show the loss of the top. The observed collapse mechanism consists in sliding of the spire top and in the resulting overturning. Once the emergency phase has passed, it is now a duty to learn from this traumatic experience and to provide new tools for the prevention of the destructive effects of future earthquakes. In this perspective, a geodatabase was designed, using the ArcGIS Pro software, for monitoring the vulnerabilities of the surveyed spires. Indeed, as we learn from the study of the effects of past earthquakes, seismic damages are recurrent for each building typology and therefore they can be predictable and avoidable. For example, by statistically elaborating the data of the designed database, a correlation arose between the levels of damage of the spires and their type of masonry arrangement. Indeed four different masonry typologies have been distinguished. The work then focuses on three damaged spires of churches belfries, proposing three consolidation hypotheses to prevent the future loss of the rebuilt top part of the spire. The structural analyses, performed with Abaqus CAE and detailed in a different work, showed that the same intervention produces different results on the different case studies: a demonstration that there is not an “absolute” best solution, but an intervention suitable for each case.