## 2 Knowledge-Based Procedure
### Seismic Vulnerability Assessment and Multilevel Evaluation  
At the end of the acquisition procedure, the seismic vulnerability assessment of the building was carried out. The outcomes of the structural characterization of the construction combined with the obtained mechanical properties can point to the most suitable approach for reliable evaluation. The outcomes of the diagnostic campaigns point out issues that are difficult to be considered in the phases of analysis. Although RC ring beams are present at the ground and first floor levels, no diaphragmatic connection is guaranteed at the roof level. In addition, the delicate and heavy clay Perret roof represents a non-structural vulnerability that could significantly affect the performance of the building under seismic motion. Furthermore, the low mechanical values of the mortar strength may prefigure poor binder capacities that can lead to disaggregation effects (masonry crumbling) [48]. These effects produced by bad mortar properties are not easy to numerically represent, thus pointing out critical issues in the performance of those structures. In the following analysis, a dual approach was used, considering both out-of-plane and in-plane behaviors. The considered local mechanisms involve the top level of the building, as it is the one without perimetral ring beams. On the other hand, global analyses have been considered, since the in situ test holes proved a good connection of the masonry walls. Of course, both approaches are more conservative than assuming a disaggregation effect, which would lead to the \"mechanism 0\", anticipating all other types of seismic activity. For the seismic investigation, the mechanical properties listed in Table 3 were adopted. The properties are based on the Bayesian upgrade of the mechanical values coming from MIT2019 [14] based on the executed tests. For the two masonry typologies, two distinct shear criteria were considered. For the stone masonry, the Turnsek and Cacovic criterion was used, while for the clay masonry the Mohr Coulomb criterion was used. The elastic moduli E were updated on the basis of the double flat-jack tests; hence, the shear moduli G were also updated considering the relationship G = E/3. The results of the compressive tests on the resistant elements were considered to upgrade the compressive strength f\({}_{\rm m}\) of the masonry types. Considering the results presented in Section 2.2, accounting for values 20% reduced, the interpolations provided by NTC2018 [13] led to a final value of f\({}_{\rm m}\) equal to 4.5 MPa for the clay brick masonry. For the stone masonry, as the outcome of the interpolation exceeded the code limits, since the accounted formulations are conceived for artificial elements and not for natural ones, the properties have not been updated according to the executed tests. Finally, the results of the above tests were adopted to update the \(\tau_{0}\) values for the stone masonry and the f\({}_{\rm v0}\) value for clay brick masonry. The relationship f\({}_{\rm v0}\) = 1.5 \(\tau_{0}\) was considered. In the computation, due to the outcomes of the mortar characterization, the detrimental coefficient equal to 0.80 for the elastic moduli and 0.70 for the resistances were applied, in order to consider the effects of the bad mortar qualities. Figure 5: Mortar compressive strength results for the different tests executed in the building. For each test, the result is given by the mean value of 15 experimental acquisitions. Both approaches of analysis were computed through the software 3 Muri (Stadata) [49, 50], using the equivalent frame method suite for the global assessment and the macro-element one for the local analyses (Figure 6). Both strategies follow a phenomenological approach where the masonry is discretized according to the experienced damage of the bearing walls.