PSI - Issue 44

Marialaura Malena et al. / Procedia Structural Integrity 44 (2023) 2052–2057 M. Malena et al./ Structural Integrity Procedia 00 (2022) 000 – 000

2053

2

According to the Standard (NTC-2018), the structural analysis of historic masonry buildings subject to earthquakes is commonly based on two distinct approaches: that of the global response to seismic actions and that of the local analysis of a-priori predetermined collapse mechanisms. This is a conventional decoupling of the structural problem due to the difficulty of addressing the seismic vulnerability of individual parts from the modelling of the whole. The aim of this work is to establish a link between the global behavior of the church and the assessment of the local mechanism by performing a two steps procedure: i) detection of the main vibration modes of the whole building with identification of the structural macro-elements that are responsible for the overall seismic vulnerability, ii) finite element non-linear analysis on the previously-identified macro-elements, to evaluate the failure pattern caused by the earthquakes. The procedure will be applied to a case of study: the church of St. Martino dei Gualdesi in Castelsangelo on the Nera river (Italy). 2. The case of study The church of St. Martino dei Gualdesi in Castelsangelo is one of the several religious buildings involved in the Central Italy earthquake (2016-2017). It has a simple and regular configuration, made up of three distinct bodies: the nave, the vestry and the bell tower (Fig.1.a). The bell tower is certainly the structural part most damaged by the seismic event with several cracks visible along its walls. In spite of this, the tower did not collapse, most probably due to the good efficiency demonstrated by the pre-inserted diaphragms inducing a box-like behaviour (Fig.1.b). Cracks are also located on the transversal walls at the connection of the arches with the longitudinal side wall (Fig.1.b). Finally, a deep crack at the interface between the roof and the curb can be observed (Fig.1. b).

Fig. 1. a) The church; b) the damage pattern after the Central Italy earthquake (2016-2017).