PSI - Issue 78

Maria Eleonora Pipistrelli et al. / Procedia Structural Integrity 78 (2026) 1911–1918

1917

Overall, a poor behaviour is observed in the Y-direction, primarily due to the prevalence of shorter wall segments and more flexible floor slabs. This behavior is consistent with the results of the preliminary modal analyses, which indicate that over 80% of the participating mass is associated with the first vibration mode in the Y direction, implying a stronger influence of seismic action along that axis.

Figure 6 : Normalized capacity curves for all the three configurations obtained in (a) X-direction and (b) Y-direction. The shear capacity V bu is divided by the weight W, while drift d is divided by the height of the control node h.

4.2 Damage patterns For each configuration, the obtained damage patterns are compared with the crack patterns observed in reality. In Configuration 1, damage was predominantly concentrated in the central portion of the façades, with diagonal cracks developing in an unrealistic distribution compared to the actual condition. Configuration 2 showed a slightly improved pattern but still failed to capture the extent and localization of damage observed in situ. Configuration 3 reproduced a damage pattern that closely mirrored the real crack distribution observed during inspections. Fig. 7 displays the damage patterns obtained from the 3Muri analysis of Configuration 3 for the north and east sides of the corner S.U. On the east side, the wall showed the presence of horizontal bending cracks in the piers of the top floor, along with diagonal shear cracks concentrated especially in the corner area, with a development that shows the damage branching out from the connection zone with the adjacent building. Also in the north wall, greater shear damage is recorded in the piers between two contiguous openings, localized especially at the intermediate level. These results demonstrate that the inclusion of surrounding masonry volumes is essential to accurately reproduce the real damage behavior of structural units within aggregates.

Figure 7 : Damage pattern obtained for Configuration 3: (a) north side; (b) east side.