PSI - Issue 78

Ciro Del Vecchio et al. / Procedia Structural Integrity 78 (2026) 913–920

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framework to facilitate analysis and reduce computational demand. This framework allows the evaluation of the repair costs of the damaged components considering the achieved damage state. To this end, the fragility curve and the associated consequence functions for structural (exterior joints, interior joints, non-conforming joints and stairs) and non-structural components (infills and partition, clay tiles, floor finishes, chimney, lighting, electrical and hydraulic systems, HVAC, etc.) are selected according to ATC 58 (2018), Cardone (2016), Cardone & Perrone (2017), Del Vecchio et al. (2020). Furthermore, the fragility curves of FRP strengthened beam-column joints (BCJs) proposed by Yurdakul et al. (2023) for shear and flexure critical exterior and interior members are selected in this study to quantify the benefits of FRP strengthening. The probability of collapse is evaluated using the procedure implemented in the framework presented in Molitierno et al. (2025). This procedure allows to assign the total value of the structure as a cost in the loss analysis if the collapse of the structure occurs. The probability is evaluated using the inter-storey drift ratio IDR and the inter-storey shear V i , which are evaluated through the NLTHs analyses performed with the simplified nonlinear model. The framework only considers global collapse (GC) as performance level (PL), while the usability damage prevention (UPD) is neglected. According to De Risi et al. (2023), sidesway global collapse (SGC) and gravity load collapse (GLC) are considered as GCs. It is assumed that SGC occurs when more than 50% of the RC members (columns and joints) fail in shear at the same floor. For the GLC, on the other hand, it is assumed that the shear capacity drops to zero at the onset of the axial failure (De Risi et al., 2023). However, since the strength degradation in RC members is not explicitly modelled, the assessment of the GLC was performed using drift-based models (Del Vecchio et al., 2020). Further details on the procedure implemented in the framework to assess the probability of the collapse can be found in Molitierno et al. (2025). In the end, the simplified framework allows the assessment of repair costs, expected annual losses (EAL) and pay-back time (PBT) for all the configuration of the building. This study reports the preliminary results of the loss assessment in the as built and retrofitted configurations of existing infilled RC buildings selected as a case study. 3. Case Study buildings Three infilled RC buildings severely damaged by the 2009 L’Aquila earthquake are selected as case study to perform the loss analysis. The plan view, the elevation and the observed damage are shown in Fig. 2.

Fig. 2. Existing infilled RC buildings selected for this study.

The buildings were designed in 70-80s to withstand moderate seismic action. In turn, they were built with poor quality concrete, absence of joint stirrups and lack of transverse reinforcement in beams and columns. The plan and elevation of the selected buildings differ from each other (see Fig. 2). The structural system consists of RC moment resisting frames in both directions of the building. The floor plan of the buildings with two (right side) and three