PSI - Issue 44

Maria Zucconi et al. / Procedia Structural Integrity 44 (2023) 315–322

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Maria Zucconi et al. / Structural Integrity Procedia 00 (2022) 000–000

The Engineering Demand Parameters (EDPs) profiles represent the starting points for probabilistic loss estimation. They were derived from the structural analysis and defined in terms of IDR and PFA for the selected HLs and for each time history analysis. Then, PACT tool requires to define the hazard curve of the site and the building collapse fragility function. The other two main steps for the loss analysis are the characterization of element fragility functions for selected damage states and the element consequence functions, which give the probability of repair costs as a function of the element damage levels. In this work, the life cycle analysis was achieved for the nonlinear 3D model, starting from the structural results obtained considering the 30 pairs of acceleration time-history records applied along the two main directions of the models (X and Y), as shown in Figure 1. The EDP vectors for both directions were defined from IDA results, as well as the global collapse fragility functions of the building. Then, a set of fragility and consequence functions were selected from the FEMA P-58 database that proposes a large number of structural and non-structural element fragility functions. In the following Figure 5, the loss hazard curve, representative of the life cycle analysis results, shows the MAR of exceeding a specific Repair Cost RC. The colors under the loss curve denote the contribution of the different HLs to the global annual loss. It is possible to note that the contribution of the first three HLs is the most relevant for estimating the EAL. This behavior is due to the higher probability of exceedance that characterized the lower HLs compared to the higher HLs described by the low probability of exceedance. Finally, it is worth noting that the selected case study is characterized by elevated residual drifts that make the structure irreparable at the third HL (30% in 50 years). The estimated EAL is equal to 1.70%, and this result remains stable if the thirty pairs of time –histories records are rotated to evaluate the influence of the directionality of the seismic action, underlining the importance of accounting the bi-directional ground motion.

Fig. 5 Loss hazard curve for the case study building accounting for bidirectional ground motion.

6. Conclusions The present paper is focused on the seismic loss assessment of a reinforced concrete structure designed without any seismic criterion. The economic losses were estimated following the FEMA-P58 methodology and were expressed in terms of loss hazard curve and expected annual losses. The selected case study refers to an existing structure designed without the capacity design criterion. The building was modeled by means of OpeenSees software, considering a three-dimensional model characterized by a weak and a strong direction, as happened for many existing structures built before the introduction of the seismic