PSI - Issue 84

Francesco Cannizzaro et al. / Procedia Structural Integrity 84 (2026) 874–881

880

Table 1. Mechanical properties.

E

f t

G t

f c

G c

G

c

w

 o



Component

MPa MPa N/mm MPa N/mm MPa MPa MPa 3100 0.15 0.05 3.85 4 1291.7 0.15 -

- -

kN/m 3

Masonry Backfill

18

250 0.001 - 462.7 0.001 -

- -

- -

104.1 - 192.8 -

0.01 1.428 17

Friction interfaces

0.001 0.6

-

Pier to arch interfaces Spandrel to arch interfaces

3027.6 0.15 0.05 3.85 4

1261

-

0.21 1

-

Table 2. Normal elastic stiffness of the piers’ foundations. k x k y k z kN/m 3 kN/m 3 kN/m 3 2200000 4200000 9400000

Response metrics are reported in Fig. 4, according to the scheme presented in Scozzese et al. (2023). Specifically, the displacement components, expressed in the global reference system, of three selected points: point 1, corresponding to the upstream midpoint of the first span at the top of the spandrel wall; point 2, corresponding to the upstream top of the spandrel wall at the midpoint of the scoured pier; and point 3, corresponding to s x , are reported. In particular, the arch settlement u z1 , the spandrel settlement u z2 , the pier settlement u z3 , the arch transverse displacement u y1 and the spandrel transverse displacement u y2 , are plotted against the normalized length of the scoured base B s / B .

Fig. 4. Displacement parameters versus scour magnitude.

The response remains limited (below 5 mm) until the scour affects approximately half of the foundation base, which may indicate difficulty in the early detection of the associated risk. Points 2 and 3 show good agreement with the results reported in Scozzese et al. (2023). Compared to that study, large displacements develop at slightly lower scour depths; however, this difference may be attributed to the adoption of a different discretization of the scour progression. In the present study, the displacements of point 1 are smaller than those obtained using the FE model; this behaviour is consistent with the DMEM formulation, which accounts for the possible decomposition of the structure into interacting macro-blocks. These results indicate that a substantial involvement of the foundation base ( B s /B =0.56) is required to produce a pronounced damage pattern and subsequent significant displacements; however, such a scour level is already associated with a near-collapse condition. Qualitatively, this suggests that the slight damage and near-collapse limit states are relatively close in terms of scour progression.