Evaluation of the sysmic risk in the church of San Pietro Caveoso - Matera

The need to preserve historical patrimony and knowledge of the current state of some structures regarding seismic vulnerability is the motivation of this research. The research aims to analyse the vulnerability of the Church of San Pietro Caveoso, located in the region of Basilicata in southern Italy. This heritage belongs to a group of important historic masonry churches in the Sassi complex and the Matera Rupestrian Churches Park, which has been recognized as a World Heritage Site by UNESCO since 1993. As it is well known, Italy has a large amount of historical constructions, but at the same time has areas of seismic risk, in this case the region of Basilicata has a moderate seismic risk. With this objective, the seismic vulnerability analysis of this patrimony was done according to the simplified method LV1 (according to the norms of literature, with indication to the current norms and in particular to the Technical Standard for the Italian construction). In order to reach this analysis, a historical survey of the church has been made, from the beginning of its construction, the thirteenth century to present day. The construction phases, the geometric survey, the history of interventions and the constructive characteristics are reported. In detail subsequently, the analysis of mechanical damage was performed on the structure, where, with a preliminary investigation, it was possible to notice the existence of cracks in the outer walls of the belfry and mainly in one of the chapels. Also, in the knowledge phase of the structure, two non-destructive tests were carried out in order to obtain a qualitative knowledge of the masonry (sonic test) and to validate historical knowledge about the existence of a lower level than the church nave (georadar test). Before carrying out the vulnerability analysis, the Confidence Factor () of the structure was still obtained. The simplified method LV1 determined 19 seismic mechanisms in the analysed church San Pietro Caveoso, that was evaluated with a vulnerability index ( ) and with macro elements more vulnerable in the mechanisms related to the façade and to the vaults of the chapels. Therefore, for the reference return period () 20 years were considered, obtaining a safety index for the condition state SLD of unsafe condition. The conclusion of the study is that in the case of preserving a world heritage, vulnerability analysis for a 20-year reference period should be taken into account in order to carry out interventions to increase the durability of the structure and in a less invasive way.