Seismic damage and fragility assessment of ancient masonry churches located in central Chile

An assessment of damage and seismic fragility of historical unreinforced masonry churches located in Chile’s central valley was carried out employing the results of a field survey of 106 ancient churches, after the 2010 Maule earthquake. The observed damage was correlated with recurrent failure mechanisms of unreinforced masonry structures, by taking into account 22 local mechanisms involving macro-elements on these churches. The average damage level suffered by each church was computed considering the global and local behaviors of the structures through a damage index computed as a weighted mean of the levels of damage observed for each mechanism. The results of this damage index method are used to obtain Probability Mass Functions and suitable probabilistic tools are used to propose Empirical Fragility Curves (EFCs) for these structures. The EFCs are directly usable by stakeholders involved in risk assessment aimed to the prioritization of possible future damage mitigation strategies and other decision making processes relative to this historical heritage.