PSI - Issue 44

Valentina Buonocunto et al. / Procedia Structural Integrity 44 (2023) 67–74 Valentina Buonocunto et al. / Structural Integrity Procedia 00 (2022) 000–000

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The data obtained from Da.D.O. was revised. In order to compare the data on the observed damage with that related to simulated damage, the authors of this paper considered that the building stock affected by the 1980 Irpinia earthquake was significantly different from that taken into account in the vulnerability analysis, as outlined in Figure 6. It was assumed that undamaged buildings did not appear in the damage survey forms collected after the earthquake. The difference between the number of buildings presents in the Da.D.O. platform and those present in the ISTAT1985 census data set was then evaluated. Such a difference was found to be about 15%, representing the number of buildings that did not suffer damage: 70% of them were attributed the damage state DS0 and 30% the damage state DS1, as done for example by Zuccaro et al. (2020) for the 2009 L’Aquila earthquake. A revision was also made for damage states DS3, DS4 and DS5 by subtracting the previously added percentages from the latter three families. This is motivated by the fact that the buildings were surveyed as individual units, so they were not considered to be structural units of building aggregates. It is understandable that some buildings had severe damage associated with surrounding structures or out-of-plane mechanisms that were not modelled in the damage simulation presented in this study.

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Simulated damage Observed damage (Da.D.O.) Observed damage (revised) Observed damage (Braga et al., 1982)

% Buildings

DS0 DS1 DS2 DS3 DS4 DS5

Fig. 6. Comparison between simulated and observed damage

In addition, the data compiled by Braga et al. (1982) were included in Figure 6 for the sake of comparison. The latter ones somewhere simulated and observed damage. The work by Braga et al. converted the extent of damage observed in the Irpinia sheets (according to a damage scale ranging from 1 to 8 differentiated by horizontal and vertical structures) into the M.S.K.-76 scale (which ranges from 0 to 5 as calculated in the Da.D.O. database). 4. Conclusions This study focused on the derivation and validation of analytical fragility curves for URM masonry buildings located in Campania region, south of Italy. The geometric data obtained from the CARTIS database were used to parametrically generate the buildings of the region. Thanks to the fragility curves obtained and entered into the IRMA portal, the simulated damage was compared to that observed available in the Da.D.O. database in the case of the 1980 Irpinia earthquake. A mismatch between the two damage distributions was found. One of the reasons is certainly the urban regeneration that has taken place from 1980 till now. Masonry structures that were heavily damaged or even collapsed in the Irpinia earthquake were most likely rebuilt using reinforced concrete or other materials. In this way, the building portfolio of the time was partly lost. Based on the work carried out in 1982 by Braga et al. (1982), the comparison between the damage observed after the Irpinia earthquake and simulated damage was improved, particularly in case of damage states DS1 and DS2. Regarding damage state DS0, simulations led to a slight damage overestimation, the opposite occurring in case of damage states DS4 and DS5. This is probably associated with the