PSI - Issue 78

Antonella Ranaldo et al. / Procedia Structural Integrity 78 (2026) 552–559

553

1. Introduction Existing masonry buildings are very vulnerable to the seismic action as demonstrated by the damage suffered in the last earthquakes. This is due to the fact that they are very old structures very likely not designed for horizonal actions. Moreover, interventions recently applied may reveal inadequate, since they are designed with a lack of knowledge in terms of construction details, material strengths, and construction evolution phases. For these reasons the scientific community is significantly engaged in predicting the existing masonry buildings behavior, considering also the damage observed after a seismic event supposed to be a reliable basis for proposing modelling criteria. Internationally, research efforts by organizations like (UNESCO, 1983), (ICCROM, 1998), and (CENAPRED, 2014) focus on developing risk assessment procedures for cultural heritage. A key guide in this area is the Italian Directive (D.P.M., 2011), which outlines a multi-level approach for assessing seismic vulnerability in historic buildings, including existing masonry churches. The Directive's approach employs three Levels of Valuation ( LVs ), such as: LV1 for territorial evaluations, LV2 for local macro-element analysis, and LV3 for global analysis. Some results of the application of the multi-level methodology on existing constructions, including masonry churches, may be found in (D’Amato et al. 2021), (Lo Monaco et al. 2023, 2024, 2025), and (Ranaldo et al. 2025). This work focuses on the seismic response assessment of some macro-elements belonging to two existing masonry churches, that are: Saint Fransis of Assisi Church located in Matera (Italy), and Jesus Resurrection Church located in Belinţ (Romania). In particular, some structurally autonomous architectural portions common to both case studies are examined. To investigate the failure mechanisms of the macro-elements, Finite Element Method (FEM) numerical models are performed for conducting a Non-Linear Push-over Analysis (NLPAs). These preliminary results are part of ongoing research that aims at comparing existing Italian and Romanian masonry churches. 2. Case studies The selected case studies are two existing masonry churches, that are Saint Fransis of Assisi Church (Matera, Italy), and Jesus Resurrection Church, (Belinţ, Romania). Both churches are located in areas with a moderate seismic hazard, as shown in the 2020 European Seismic Hazard Model - ESHM20 (Danciu et al. 2021). This model reports the spectral pseudo-acceleration Sa associated to a vibration period equal to 0.2 s [ Sa (0.2 s)] with a Probability Of Exceedance (POE) of 10% in 50 years (Fig. 1a).

a

b

Fig. 1. (a) ESHM20 maps for Sa (0.2 s) (Danciu et al. 2021); (b) spectra of the horizontal seismic action corresponding to LSLS .

Response spectra for Life-Safety Limit State ( LSLS ) are examined for comparing the seismic action of the two cities considered, according to the corresponding national standards. As regards Matera, the seismic action is defined according to the Italian Design Code (M.D., 2018) with the following parameters: nominal life V N = 50 years; coefficient of use C U = 1.5; reference period V R = 75 years; return period T R = 712 years (10% in 50 years POE). In this case, the expected ground acceleration corresponds to a g,LSLS = 0.160 g, where a damping ratio (ξ) equal to 10%