PSI - Issue 78

Giuseppe Brandonisio et al. / Procedia Structural Integrity 78 (2026) 2147–2153

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for a better understanding of the structural layout and for a more targeted seismic vulnerability assessment, taking into account the construction heterogeneity and historical evolution of the complex.

2.3. FEM modeling The seismic vulnerability assessment was carried out through nonlinear static (pushover) analyses. The masonry walls were modelled using one-dimensional beam-type elements, following the Equivalent Frame Model (EFM). According to the Italian Building Code (NTC2018) (CM209), masonry walls are modelled using one-dimensional beam elements through the so-called Equivalent Frame Model. The walls are subdivided into vertical elements (piers), horizontal elements (spandrels), and their intersections (rigid joints). Piers and spandrels are modelled as columns and beams of a two-dimensional frame, respectively, while the joint regions are represented by rigid links. This modelling approach enables the use of a lumped plasticity model, with plastic hinges assigned at predefined locations (i.e., at the ends of beams and the top and bottom of columns) to capture flexural and shear nonlinearity. Such a structural representation allows for the execution of nonlinear incremental (pushover) analyses to assess the collapse mechanisms of the masonry walls.

Fig. 3 Global and locals FE models by CDS-WIN software

To evaluate the influence of structural complexity and inter-body interaction (Brandonisio and De Luca, 2024)., eight finite element (FE) models were developed and analysed (see Fig. 3 ). These include: one Global Model, representing the entire building as a single structural system; seven Local Models, corresponding to Bodies 1 through 7, each modelled as an isolated structure by neglecting the interaction with adjacent bodies. This modelling strategy allows for a comparative assessment of the seismic response of the individual components versus the global structural behaviour. 2.4. Seismic Vulnerability assessment The results of the pushover analyses are summarized in the following paragraph: eight pushover curves are showed in Fig. 4, each one corresponding to a single seismic loading case, namely: Pushover1=Mode X+; Pushover 2=Mode X-; Pushover 3=Mode Y+; Pushover 4=Mode Y-; Pushover 5=Mass X+; Pushover 6=Mass X-; Pushover 7=Mass Y+; Pushover 8=Mass Y-.