PSI - Issue 44

Francesco Nigro et al. / Procedia Structural Integrity 44 (2023) 1704–1711 F. Nigro, R. Falcone, E. Martinelli/Structural Integrity Procedia 00 (2022) 000–000

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Fig. 4. Plan distribution of the braces in the case of “target A” analysis.

Table 3. (a) Profiles used for the global intervention at the bottom story in the case of “target A” analysis. (b) Number of local interventions for each story in the case of “target A” analysis (a) Global intervention (b) Local interventions through FRP layers Beam (bay) Steel profiles of the braces at the bottom floor ( ID sec ) Story Number of confined columns Total Number of FRP layers 2 & 18 HE 100 B 1 st 1 1 30 & 31 HE 100 B 2 nd 4 6 15 HE 120 B 3 rd 1 3 4 th 2 4

3.2.2 “Optimal” upgrading solution for target class “B” Table 4 highlights the number of local interventions (for each story) needed to upgrade the structure to the “B” class, reporting also the number of FRP layers employed.

Table 4. Number of local interventions for each story in the case of “target B” analysis Local interventions through FRP layers Story Number of confined columns Total Number of FRP layers 1 st 19 28 2 nd 2 2 3 rd 4 5 4 th 1 3

3.3 Result discussion In the present Section, the main result of the analyses reported in the Section 3.2 are summarized. It is possible to note that: • the proposed GA is able to accomplish efficiently the request of the user, since it is able to “detect” the intervention needed for the structure depending on the seismic risk class considered as target of the analyses; in order to achieve an upgrading that leads to the “A” seismic risk class, it is necessary to add to the structure supplementary bracing systems that are able to significantly increase the strength and the stiffness of the structure, reducing the seismic displacement demand, as well; • when supplementary bracing systems are needed, although the Algorithm is able to detect that the perimetral position is more convenient (rather than the internal one) for them, the selected plan distribution of the braces