PSI - Issue 44

7

A. Sandoli et al. / Procedia Structural Integrity 44 (2023) 1332–1339 / Structural Integrity Procedia 00 (2022) 000 – 000

1338

8

0,0 0,2 0,4 0,6 0,8 1,0

7

6

5

4

P(ds>DS4|PGA)

R=0 km R=10 km R=20 km R=30 km

Sabetta and Pugliese 1987

Crespellani et al. 1998

Fig. 5. Multi scenario representation through the hazard disaggregation analysis

100%

RLS

RLS

C_01 pre-1980 C_01 post-1980

CLS

CLS

80%

Limit States (LS): RLS= Reconstruction LS OLS = Operational LS DLLS = Damage Limitation LS SLS = Serviceability LS LSLS= Life safety LS CLS= Collapse LS IDLS= Initial Damage LS

60%

LSLS

LSLS

40%

%RC

20%

DLLS

DLLS OLS IDLS

OLS

0%

0% 2% 4% 6% 8% 10% 12%

Mean annual frequency of exceedance (  )

Fig. 6. Comparison between pre- and poast-1980 EALs for Balvano In this paper, five earthquakes with magnitude M=4.0, 5.0, 6.0, 7.0 and 8.0 and four site-to-source distances R=0, 10, 20 and 30 km have been chosen to represent the variability of the seismic hazard thus twenty damage scenarios have been predicted. The MSM s derived through the attenuation laws given by eqs. (4) and (5) have been represented in Tab. 2. In addition, the same MSMs have been represented through the three-dimensional histogram in Fig. 5. As it can be observed, for earthquakes with M>6.0, independently from the distance R, very severe damage scenarios are expected for Balvano; while for lower values of M, significant damages to buildings are expected for earthquakes having epicenter in a radius between 0-10 km from Balvano. 4. Simplified economical losses scenarios In this Section, Expected Annual Losses (EAL) pre-and post-1980 have been estimated through the simplified procedure (conventional approach) presented in the Italian “Guidelines for seismic risk classification of the constructions ” (Ministry Decree n. 58/2017). EAL estimates the economic losses associated with the damage of structural and non-structural elements during the reference life of the construction, expressed as a percentage of the Reconstruction Costs (%RC). To each Limit State (LS), repair costs have been associated, calibrated on a consistent number of building stocks damaged during th e 2009 L’Aquila (Italy) earthquakes (Cosenza et al. 2018). Basically, the methodology refers to a single building, while in this paper, it has been considered referred to as the single urban compartments of Balvano. Hence, the values PGA/g at ULS (LSLS in the Guidelines) coincide with the average ones obtained from the fragility curves, while the PGA/g at DLLS have been calculated by dividing the values at ULS with a behavior factor q=2.0. In Fig. 6, the %RC-mean annual frequency of exceedance of an earthquake (  curves referred to the case pre-and post-1980 are represented, resulting EAL= 5.36% for the case pre-1980 and EAL= 0.50% for the case post-1980. This highlights that the construction of new RC buildings according to the seismic recommendations released in that years and the retrofitting interventions applied to masonry buildings have been significantly effective in reducing monetary losses.