Mechanical Modelling for Simplified Seismic Analysis of Existing RC Churches and Fragility Curves

This paper proposes an efficient model for estimating the seismic performance of reinforced concrete (RC) churches and for developing typological fragility curves using a mechanical approach. The study focuses on evaluating the vulnerability of RC church buildings in Naples, using a sample of seven churches with the “Sacri Cuori di Gesù e Maria” Church as the primary case study. This church has been then analyzed in the non-linear filed by means of the software SAP2000. The influence of different modelling hypotheses, e.g., roof’s inclined, absence of box-type behavior, has been evaluated. A simplified model based on elastic analysis and limit analysis has been implemented to solve the 2D static scheme and to evaluate the seismic performance of the churches for different code-based Limit States. As a result, an efficient generation of bilinear capacity for the detailed study of a single church is available; it is also useful for the generation of fragility curves. Validation against non-linear SAP2000 results showed that while detailed models offer comprehensive insights, the proposed simplified model effectively captures the essential behavior of the structures and provides reliable seismic vulnerability assessments. The computed fragility curves indicate that the seismic performance of this building’ class is medium to high, emphasizing the need of extended analysis aimed at the definition of proper interventions to increase the level of seismic safety. Therefore, the proposed model proves to be a practical tool for large-scale seismic vulnerability evaluations and the rational deployment of risk mitigation resources.