PSI - Issue 78

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

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1. Introduction Most of the existing reinforced concrete (RC) buildings in the Mediterranean region are vulnerable to moderate to-high seismic actions and may exhibit damage to structural and non-structural components under earthquake events. This was outlined by the recent earthquake in Turkey, which affected the economy and the resilience of an entire region (Vuran et al., 2025), remarking the urgent need for a seismic risk mitigation strategy, which is crucial for planning the prioritization of strengthening intervention for existing buildings at the regional level. Several retrofitting techniques are available to date to enhance the seismic performance of existing RC buildings. Among these techniques, FRP solutions have widespread in the designed practice due to their light weight, ease of application and overall cost effectiveness (Del Vecchio et al., 2021). This solution can be used as a local strengthening to prevent shear failure in BCJs or columns due to the infill-to-frame interaction. It can be applied from the exterior of buildings to increase the shear capacity of the BCJ using of novel pultruded FRP mechanical anchors with one end splayed dry fibers, which helps to prevent debonding failure while minimizing the level of disruption for the building’s occupants (Del Vecchio, Di Ludovico, et al., 2024). This makes FRP solutions promising and suitable to be used for a large-scale intervention strategy. In this context, the development of a reliable and accurate seismic loss assessment framework is crucial to properly assess the benefits of strengthening interventions, planning effective strategies to mitigate economic losses and have resilient communities in earthquake prone areas. Several seismic loss assessment frameworks (e.g. FEMA P58 (ATC, 2018), DBELA (Bal et al., 2008) and Simcenter (Lu et al., 2020)) are available. They are based on the Performance Based Earthquake Engineering (PBEE) framework (Porter, 2003), allowing to assess the structural performance of buildings, the associated damage and the related consequences. The FEMA-P58 framework, which accounts for the repair losses at component level, has been implemented in a practical design tool (Performance Assessment Calculation Tool (PACT) (ATC, 2018) to help researchers and designers identify the most critical components and have useful insights for the definition of efficient \strengthening intervention (Del Vecchio et al., 2020). Refined frameworks commonly require high computational effort to perform the analysis. This makes them not suitable for extension to the regional scale. Therefore, reliable simplified models validated against experimental data may represent reliable alternatives for performing the analysis and reduce computational effort. Finally, the proposed tools should account for direct cost associated with the retrofit intervention, for the expected annual loss (EALs) in relation to the direct and indirect (interruption of building functionality) cost. This is highly important at regional scale intervention as it also estimates the payback time, which gives an idea of the number of years that is required to recover the initial economic investment. This paper presents a PBEE-based framework implemented in the Matlab® environment for simplified loss assessment of existing RC buildings at regional scale. Case study existing RC buildings typical of Italian construction was selected from the database of the existing buildings damaged and repaired after the 2009 L’Aquila earthquake. The seismic performance are assessed through non-linear time history analysis (NLTHs) using simplified nonlinear numerical models. The hysteretic response of each floor representing the simplified model was calibrated and validated on full-scale tests on multi-storey infilled RC frames tested under pseudo-dynamic loading protocols. The seismic losses of structural and non-structural components are evaluated using a component-based approach considering the engineering demand parameters (EDPs) obtained from the analysis. Finally, the results in terms of expected annual losses (EAL) and the benefits in the use of minimally invasive FRP strengthening interventions are discussed. 2. Simplified Loss assessment Framework The simplified loss assessment framework proposed by Del Vecchio et al. (2024) and developed in the Matlab® environment (The MathWorks Inc., 2022) is schematically represented in Fig. 1. It relies on consequence functions of components typical of the Italian standards and calibrated on actual repair costs obtained from the extensive work of data collection and analysis carried out by the ReLUIS consortium since the 2009 L’Aquila earthquake (Di Ludovico et al., 2017, 2022). It was developed with reference to existing infilled multi-storey RC buildings to assess seismic losses and to evaluate the benefits of strengthening at a regional scale level accounting for record-to-record