PSI - Issue 78

Maria Zucconi et al. / Procedia Structural Integrity 78 (2026) 839–844

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Figure 2 shows the same analysis for DSt2, where higher damage severity leads to proportionally larger Cr% values. For one-story buildings with full-perimeter damage, Cr% reaches approximately 33%, remaining below 6% in six story buildings. Also, in this case, the marginal impact of additional damaged bays decreases once a significant portion of the perimeter is already affected. This effect — commonly referred to as diminishing marginal impact — can be attributed to three main factors: I. fixed costs saturation, since a portion of the intervention costs is activated with even limited damage; II. cost normalization, because Cr% is expressed relative to the total floor area, which increases with building height; III. economies of scale, whereby repairing a larger number of bays does not imply a strictly proportional increase in total repair costs. These results highlight that even in the absence of structural damage, tsunami-induced losses related to infill wall failure can represent a significant portion of the total replacement cost — particularly in compact or low-rise buildings. Incorporating these effects into consequence models is essential for capturing the true economic impact of tsunami scenarios involving non-structural components.

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DSt2 Damaged 14 bays Damaged 10 bays Damaged 6 bays Damaged 3 bays Damaged 1 bay

Repair cost ratio [%]

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N. of Stories

Figure 2 Repair cost ratio (Cr%) for DSt2 as a function of the number of stories with respect to the number of damaged bays.

5. Conclusions This study presented a methodology for estimating tsunami-induced economic losses in the absence of direct observational data, by integrating seismic repair cost information with tsunami-specific damage classifications. The approach enables the derivation of consequence functions for reinforced concrete residential buildings typical of the Italian coastal context, with particular focus on non-structural damage to infill walls at the ground story. A key advancement introduced in this work is the inclusion of uncertainty in the extent of infill wall damage, a factor often neglected in simplified loss models. By applying the methodology to a synthetic, yet realistic, RC frame configuration, a parametric analysis was carried out to assess how repair cost ratios (Cr%) are influenced by both the number of stories and the length of the damaged infills. The results confirm that non-structural damage can represent a substantial portion of the total replacement cost, particularly in low-rise buildings. Moreover, the analysis reveals that the marginal increase in Cr% decreases as more bays are affected, due to fixed cost saturation, normalization effects, and economies of scale in repair interventions. The proposed framework lays the foundation for scalable loss estimation in tsunami-prone areas with limited empirical data. Future developments will focus on extending the methodology toward probabilistic formulations and