PSI - Issue 78

Ciro Canditone et al. / Procedia Structural Integrity 78 (2026) 379–386

383

with the Loggia’s vaulted ceiling system – and transverse loads accounting implicitly for the main Palace body’s vaults and pitched roof.

(a)

(b)

(c)

The model was then subjected to sudden base restraint loss due to bedrock failure, starting from this equilibrium condition. Four scenarios were considered: a first scenario, considering full support loss for the main façade, and hence an unsupported length equal to L y ; three corner scenarios, gradually involving larger fractions (1/12, 1/6, 1/3) of the plan lengths L x (parallel to the flange walls) and L y (parallel to the main façade). Dynamic analyses were run to consider inertial effects on load redistribution and failure mechanisms, with a 0.025 s time-step, no internal step subdivision and total duration equal to 20 s. Analyses were run using a 16 GB RAM, AMD Ryzen 7 4700U (2 GHz) processor-equipped machine and took approximately 45 minutes each. Analysis results under the first scenario, in which the whole length L y of the Loggia’s façade was supposed to incur into foundation-level failure, are recollected in Figure 4. (a) (b) (c) Figure 3. Results from gravity load analysis of the fixed-base model: (a) principal compressive stresses, expressed in tonf/m 2 ; (b) maximum displacements, expressed in m; (c) cracked springs distribution, accounting also for pre-existing damage.

1.9 s

20.0 s

2.3 s

100% L y

Figure 4. Progressive collapse sequence resulting from foundation- level failure affecting the Loggia’s main façade.