PSI - Issue 78

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

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The repair costs of drift-sensitive (i.e. infills, partitions, joints and stair) and acceleration-sensitive (i.e. clay tiles, chimney, light, raised access floor, cold or hot water piping, sanitary equipment and low voltage switchgear) components of the as-built configuration for the return period T R of 2475 years are also reported in Fig. 3 (b), (d), (f). The results show that most of the repair costs (between 70 and 90%) are related to drift-sensitive components. The costs associated with the structural components (i.e., joints and stair) impact 30-50% on the total costs, while the non-structural components (i.e. infills and partitions) impact 45-70% on the total costs. This highlights how damage to structural and non-structural components heavily affects the repairs costs, remaking the need for retrofit solutions to reduce the damage and the associated losses. Fig. 3 (a), (b), (c) shows the results in terms of mean total costs evaluated for the as-built configuration. The costs are compared with the reconstruction costs considering all return periods (i.e. from 30 to 2745 years). In addition, the total repair costs for the return period T R of 2475 years are compared with the actual repair costs available for the selected buildings. For the estimation of the mean total costs, the simplified framework accounts for the probability of collapse and assigns the total value of the structure as the cost if the collapse occurs. Otherwise, the costs are evaluated as the sum of the repair costs related to the drift sensitive and the acceleration-sensitive components. The results show that the mean total cost increase for the four floor building is almost linear between the return periods of 30 and 201 years (Fig. 3 (a)). From the return period of 475 years the cost increased significantly due to the increasing probability of the occurrence of the collapse. A similar result can also be observed for the two-floor building, where the repair costs start to increase from a return period of 975 years instead (Fig. 3 (c)). However, the mean total costs estimated for these buildings are lower than their reconstruction costs. In addition, the costs for a period of 2475 years are higher than the actual repair costs since the costs are affected by the collapse. In contrast, the mean total costs of the three-floor building achieve the reconstruction costs at a return period of 140 years (Fig. 3 (b)). This result shows that for this building the 100% probability of collapse is achieved for this building at this return period, indicating the occurrence of structural collapse under moderate intensity earthquakes. 4.2. Effectiveness of FRP strengthening The loss analysis is also performed for the retrofitted configuration to estimate the mean total cost and quantify the benefits of FRP strengthening in terms of cost reduction.

(a)

(b)

(c) Fig. 4. Results in terms of total repair costs estimated for as built and the retrofitted configurations for the return period T R of 2475 years. To this end, the assessed costs in Fig. 4 are compared with the costs evaluated for the as-built configuration (see