Seismic Vulnerability Assessment of Churches Through an Expeditive Evaluation Form: Application to a Representative Sample from Central Italy

This paper addresses the seismic vulnerability assessment of churches in Central Italy and discusses the main outcomes of the in-situ survey activities carried out within the cooperation agreement between the Italian Network of University Laboratories of Seismic and Structural Engineering (ReLuis) and the Ministry of Cultural Heritage (MIC), aimed at collecting structural and damage information of existing churches. The seismic vulnerability assessment is performed on the basis of an empirical methodology applied through the use of the MaCHRO evaluation form. A predictive model, already calibrated for churches of the inner Abruzzi, is here extended to the Central area of Italy where, due to the high seismicity, cultural heritage features major alterations occurred over time. In the first part of the paper, the analyzed sample of churches is presented. A wide description of the anti-seismic devices and fragility indicators recurrent in the ancient masonry buildings of the territory is provided, highlighting their fundamental role in preventing (or promoting) specific local failure mechanisms. Statistics regarding all information of interest from a seismic viewpoint are given for the entire sample. In the second part of the work, the vulnerability of each church is assessed in terms of vulnerability indices (IVs), evaluated according to the procedure given by Italian Guidelines of Cultural Heritage. These indices account for both the sources of fragility and the existence of possible protection devices for each macro-element. Finally, based on the obtained IVs, fragility curves for predicting the extent of probable earthquake-induced damage in the analyzed churches are estimated. The results are proven to be useful for seismic risk mitigation purposes, allowing to define priorities of intervention on a large scale.