Crolli causati dagli eventi sismici in Italia: analisi di due casi recenti in Valnerina

In a previous paper [Borri and Sisti 2017] the collapses of three churches located in Campi, a small village near Norcia (Central Italy), were investigated: Santa Maria di Piazza, Sant'Andrea and San Salvatore. It was shown that the main cause of these collapses was the underestimation of the structural problems of these historic masonry constructions. According to this, although extensive researches have been carried out [Marchetti 2001] in at least two of these case studies to highlight their criticality structural state, no interventions aimed to reduce the seismically vulnerability were adopted at that time. This paper presents a nonlinear static analysis and a simplified approach based on the kinematic theorems of limit analysis performed on two of these churches to evaluate how their collapse could have been prevented by applying simple and nonintrusive retrofitting works (e.g. steel ties).