PSI - Issue 78

Matteo Calzolari et al. / Procedia Structural Integrity 78 (2026) 1119–1125

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Fig. 3. Settlement of the foundation in the left portion of the building.

Fig. 4. Overturning mechanism.

It is therefore crucial to identify and assess such local overturning mechanisms, in order to plan targeted interventions aimed at mitigating these vulnerabilities, as discussed by Degli Abbati et al. (2014), and to ensure that masonry piers have a predominantly in-plane response, as demonstrated by Mallardo et al. (2008). 4. Kinematic analysis of mode 1 mechanisms An effective analytical approach to estimate structural capacity under horizontal loads is based on limit analysis. In particular, by applying the kinematic theorem it is possible to identify the most probable collapse mechanism among all kinematically admissible mechanisms that can be hypothesized for the structure, which is the one associated with the minimum multiplier of the gravitational loads. In this case, the observed crack pattern clearly indicates that the most heavily damaged area corresponds to the main facade. Therefore, this portion of the structure will be analyzed through a linear kinematic approach, in order to determine the activation acceleration of the different failure mechanisms. The cracks on the main facade are located in the two uppermost levels of the building; thus, the portion considered in the first out-of-plane overturning mechanism is the one shown in Fig. 4. A review of the various structural alterations the building has undergone revealed that, in February 2012, shortly before the seismic event, tie rods were installed at the intersections with orthogonal walls on the main facade, as highlighted in Fig. 4.