PSI - Issue 78

Matilde Natalizi et al. / Procedia Structural Integrity 78 (2026) 449–456

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a)

b)

Fig. 3. Analysis results in the form of histograms for different intervention plans.

Fig. 3 shows, in form of histograms, the cost-benefit analysis adopting the intervention scenarios of Table 3. In detail, Fig. 3.a reports the values of ∆ ( ) and ∆ , while Fig. 3.b those of % and . By observing the figures, it can be seen that Plan 8 offers a good reduction in vulnerability compared to the other plans, despite high costs and . Whereas, Plan 9, appears to be very favorable as it has low , comparable, for example, to that of Plan 1 (which involves the insertion of tie rods in the entire municipality), but with a reduction in vulnerability of almost double. On the other hand, Plan 10 represents a kind of average of the previous plans in terms of and vulnerability reduction. It is important to remember that the results presented in this paper are closely linked to the municipality chosen in terms of site seismic hazard and sample composition, as well as by the variables selected and the simplifications adopted for the analysis. The optimal intervention plan depends on the defined objectives and the constraints, such as a minimum acceptable vulnerability reduction, cost limits, or maximum allowable payback time. Regardless, the adopted method allows a rapid assessment of the benefits of structural intervention on masonry buildings, and due to the low computational burden required, this approach is particularly suitable for making realistic large-scale predictions of seismic vulnerability reduction strategies. 6. Conclusions In this paper the effectiveness of the traditional consolidation interventions in the seismic risk mitigation has been shown. In particular, typological fragility curves have been shown to be effective tools for estimating expected losses and assessing the seismic vulnerability of buildings at a territorial scale, while also supporting the planning of efficient and targeted interventions. An interesting use of fragility curves has been proposed, based on the logic that any intervention that modifies the structural parameters which define the typology according to the AeDES form, leads to an effective seismic improvement, measurable through a transition to a less vulnerable typology. This approach makes it possible to rapidly and objectively assess the expected benefits of an intervention, expressed in terms of loss reduction, which can be calculated as a percentage of reconstruction cost ( ) under specific seismic scenarios, or as expected annual loss . By defining certain variables such as the costs of the interventions, the annual interest rate and the reconstruction cost per square meter, it is also possible to carry out a benefits-costs analysis, evaluating the costs of the intervention and the relative amortization time. Intervention matrices can be created to guide strategic decisions in a rational and measurable way, oriented on resource optimization. The application of this methodology shows that uniform intervention plans, applied indiscriminately to the entire building stock, are often less effective than differentiated strategies built on a combination of structural typology and specific objectives. In conclusion, intervention matrices derived from typological fragility curves enable the planning of preventive strategies based on quantitative evidence. This approach represents a concrete opportunity to improve seismic risk management, especially in municipalities where vulnerability is high, resources are limited, and decisions must maximize intervention effectiveness.