PSI - Issue 84

Siro Casolo et al. / Procedia Structural Integrity 84 (2026) 1214–1221

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the left arch and the masonry element of the abutment. The impact in Test B (Figure 5, right), on the other hand, only causes the collapse of the side arch, regardless of the angle. Tests C and D lead, in some cases, to the development of a global collapse mechanism in the structure (Figure 6). In particular, Test C, with an angle of incidence of 90°, produces only the disintegration of the infill, while with an inclination α=45° , the collapse of both the side arch and the central arch is also activated, with a bending of the left pier (Figure 6, left).

Fig. 5. Deformed shapes obtained for Tests A and B varying the angle of impact.

In Test D, the inclination α=45° leads to the collapse of the central arch, with an upward projection of the rigid elements determined by inertial effects and infill-masonry adhesion. The same test with an angle of incidence of 90° leads to the collapse of the central arch together with the bending of the pier and the contraction of the right arch (Figure 6, centre). Test E, regardless of the inclination, leads to the local collapse of the keystone of the central arch (Figure 6, right).

Fig. 6. Deformed shapes obtained for Test E varying the angle of impact.

= 0.050

= 0.075

= 0.100