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

1786

3

indices are then used to define marginal costs to be investigated for the three different structural types. Some remarks on the formulations found enable some final considerations useful to support future risk mitigation strategies. 2. Seismic retrofit intervention covered by National Seismic Prevention Plan (NSPP) Out of 965 million euros granted, 724 million (about 75% of the total allocation) were used to carry out 1,207 interventions of vulnerability reduction on public buildings with either a strategic task in the emergency phase or a critical relevance for the consequences of their collapse (i.e. buildings hosting regional, provincial, municipal administrative services, school buildings, hospitals and health facilities, security activities, and other similar services). For 346 interventions out of 1,207, the NSPP allocation of 84 million euros was increased by additional resources provided by co-funds from local administrations appointed for their execution. Therefore, the total cost relevant to structural interventions, including co-funded resources, amounts to 808 million euros. According to the Italian National Technical Standards for Construction (NTSC) issued in 2008 and updated in 2018, three alternative intervention types are being granted to reduce the vulnerability of public buildings: (i) local strengthening, (ii) seismic upgrading, and (iii) demolition and reconstruction. Compared to the other two interventions, seismic upgrading was the most exploited: 999 interventions corresponding to a total cost of 656 million euros. Table 1 illustrates, for the three intervention types, the number and cost of interventions, specifying between NSPP funds and co-funded interventions.

Table 1. Seismic retrofit interventions, relevant NSPP, and co-financed funds.

Total n. of Interventions

NSPP fund [M€]

N. of co-financed interventions

Intervention type Local strength. Seismic upgrading

Co-financed fund [M€] Costs [M€]

36 M€ 656 M€ 116 M€

88

33 M€ 592 M€ 99 M€ 724 M€

27

3 M€ 64 M€ 17 M€ 84 M€

999 120

266

Dem. and reconstruction

53

Total 808 M€ Regardless of the intervention type, structural interventions mainly refer to buildings hosting administrative services (regional, provincial, municipal) and school buildings. Fig. 1 shows the number of interventions (a) and total costs (NSPP and co-financed fund) as a function of the intervention types and intended use (b). 1,207 346

(a)

(b)

Fig. 1. Number of interventions (a) and total costs (NSPP and co-funding) (b) for the three intervention types and intended use.

3. Building characteristics Out of the 1,207 buildings funded by the NSPP, 42% have a reinforced concrete (r.c.) structure, 39% masonry structure and 14% have mixed, steel, or other structures, while for the remaining 5% no information is available. As shown in Fig. 2, the distribution of structural types significantly changes as a function of the intended use. In detail, the city halls and buildings with other administrative use, typically located in the historic centers, are mainly featured by a masonry structure (308 of 625), differently from other services like hospitals, which are more often made of r.c. structures.