Damage assessment and partial failure mechanisms activation of historical masonry churches under seismic actions: Three case studies in Mantua

The structural safety and seismic performance assessment of historical masonry churches belonging to cultural heritage is currently a topic of increasing interest in Italy. Recent Italian seismic events have proved that severe damage or collapse can be caused to such typology of structures even by earthquakes of small-to-moderate magnitude. This paper describes the damage occurred in three important historical masonry churches of the outstanding cultural heritage in Mantua, Northern Italy, after the 2012 Emilia earthquake and presents the results of extensive numerical investigations carried out on detailed FE models with an elasto-plastic damage constitutive law for masonry. Historical and documentary research, on-site surveys and visual inspections were fundamental to identify the critical elements and obtain a thorough detailed knowledge of the churches for the development of accurate numerical models. The results of advanced FE analyses were used to investigate the causes of the crack patterns observed after the earthquake, indicating that the damage distribution detected in the churches can be simulated satisfactorily by the numerical approach adopted. Moreover, this study provides additional information on the seismic response of the three churches analyzed under higher PGA than those registered in Mantua during the 2012 Emilia earthquake. Comparisons among the seismic response of the churches are made in terms of predicted damage distribution, maximum normalized displacements and energy density dissipated by tensile damage.