PSI - Issue 44

Elena Speranza et al. / Procedia Structural Integrity 44 (2023) 1784–1791 Elena Speranza et al../ Structural Integrity Procedia 00 (2022) 000–000

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(a) Reinforced concrete

(b) Masonry

(c) Mixed, steel or other

Fig. 4. Distribution of safety indices before intervention and relevant cumulative distributions for reinforced concrete (a), masonry (b), and mixed, steel or other structure (c). 4. Costs According to NSPP regulations, the endowment allocated for each building is calculated as a function of intervention type and of its pre-intervention seismic safety index α ante , assessed through a seismic safety verification compliant to National Technical Standards for Constructions (NTSC). Different conventional costs, per cubic meter of the total volume of the building, are defined concerning the three intervention types considered, as follows: i) 100 € for local strengthening intervention; ii) 150 € for seismic upgrading; iii) 200 € for demolition and reconstruction. These costs, adopted for the first 7 years of the NSPP, have been recently upgraded following the prosecution of the Plan issued with Law145/2018. Different unitary contributions are defined based on the safety indices: 100% of the conventional total cost if α ante ≤ 20%; (1) [(380 - 400 α ante )/3] % of the conventional total cost if 20% < α ante ≤ 80%; (2) 0% of the conventional total cost if α ante >80%. (3) In other words, a full conventional cost is assumed, in the case of α ante lower than 20%; while no contribution is foreseen when α ante is greater than 80% and a decreasing function of the unitary contribution is assumed for α ante range between 20% and 80%. Concerning the building sample under observation, around one-half is characterized by seismic risk indices lower than 20%, therefore benefitting from the full conventional cost. In terms of average unitary costs, including the co-funding when present, costs are equal to 61.3€/m 3 for local strengthening,131.3€/m 3 for seismic upgrading, and 207.2€/m 3 for demolition and reconstruction. Number of interventions, mean unitary resulting costs per cubic meter and total costs sustained, including co-funds from local administrations, for the three intervention types and for the different structural types are sketched in Fig. 5a, Fig. 5b, and Fig. 5c, respectively. One can note that the average unitary costs seem to be unaffected by the structural type. Furthermore, for the reasons above explained, these are on average lower than the conventional costs grantable for local strengthening and seismic upgrading interventions (100 €/m 3 and 150 €/m 3 respectively), despite the additional resources provided by co-funding.

(a) Reinforced concrete

(b) Masonry

(c) Mixed, steel or other

Fig. 5. Number of interventions (a), mean unitary costs (b), and total costs (c) for the intervention type and structural type.