PSI - Issue 64

1740 Raul Berto et al. / Procedia Structural Integrity 64 (2024) 1733–1742 8 Raul Berto, Chiara Bedon, Andrea Mio, Alessandro Mazelli, Paolo Rosato / Structural Integrity Procedia 00 (2019) 000 – 000

1.368 1.790 1.860 1.053 1.193 0.526 (min.)

Mean value

Table 13. The preference relation for OSB vs CLT. OSB vs CLT CLT vs OSB OSB vs LWC LWC vs OSB CLT vs LWC LWC vs CLT P -1 P Q Q -1 Q Q -1

Fig. 3. Preference relations graph.

5. Discussion of results An extensive comparative analysis of results was carried out (Berto et al., 2024). From the analysis, in particular, the CLT solution emerged as the best compromise, dramatically outranking the OSB solution and marginally outranking the LWC one. When considering static and seismic verifications, LWC performs best, while OSB performs the most poorly and CLT offers an intermediate solution. The application of OSB panels slightly increases the SLS behaviour but achieves results similar to CLT at ULS. Besides, due to the high creep of LWC, the SLS behaviour of LFW and CLT approaches is mostly comparable. Finally, CLT and LWC strategies have almost the same performance in relation to the DL limit states (124% vs 128% respectively). Regarding the environmental implications, the impacts of both the OSB and CLT solutions are strongly related to the use of steel angular reinforcements, which contribute to nearly half of their scores (OSB: 54.30 % and 46.20% for water consumption and GHG emissions, respectively; CLT: 42.40 % and 45.40 % for water consumption and GHG emissions, respectively). The wooden-based materials are responsible for more than a quarter of the overall impacts (between 24.90% and 37.80%), while the remainder can be mainly allocated to other steel products (screws, rods, …). It is worth mentioning that the landfill disposal of OSB panels generated nearly 10% of the overall GHG emissions. The most impactful materials within the LWC solution are concrete (51.60% of water consumption and 51.50% of GWP) and the reinforcing steel (27.50% and 25.70%). Other non-negligible contributions are generated by steel products and by the landfill disposal of concrete. Overall, OSB emerged as the most environmentally friendly solution, generating the lowest scores for every category. The reduced difference to the optimum solution makes the CLT alternative potentially still viable, even though its ratings for GWP and water use are 10% and 20% higher. LWC, which consistently scores higher in comparison (32% and 39%) should be used only if the alternatives gain lower scores across the multi-criteria analysis. 6. Conclusions This study evaluated three different alternatives for the structural retrofit of a historic building, considering not only structural aspects, but also environmental, economic, and architectural compatibility issues. Moreover, temporal aspects were also properly included in the analysis. The CLT solution offers the best compromise, providing a significant improvement in static and seismic performance, low invasiveness, high reversibility, and good environmental performance. The present study could be further extended with the implementation of a sensitivity analysis on results, to verify their robustness. Uncertainty about future performances, in different aspects, could be also adequately incorporated into a Monte Carlo analysis or by using a fuzzy approach. CRediT authorship contribution statement Raul Berto: conceptualization, methodology, investigation, writing – original draft, validation, project administration. Alessandro Mazelli: investigation (structural aspects), writing – original draft. Paolo Rosato: writing – original draft, validation, supervision. Chiara Bedon: validation, supervision. Andrea Mio: investigation (environmental aspects),