## 5 Discussion
CFRP leads the ranking when the weight of the construction cost criterion is reduced when the architectural impact criterion is increased and in the scenario with equal weights for all criteria. Similarly, in the MABAC method, STE ranks first in 15 scenarios. At the same time, CFRP emerges as the best option when construction costs are lower and in the equal-weight scenario. CFRP is consistently ranked as the best option across all scenarios analyzed for the CODAS and MARCOS methods. Notably, STA ranks second when the environmental impact weight during the manufacturing stage is increased in the CODAS method and when equal weights are applied in both the CODAS and MARCOS methods. Based on the results from the four MCDM methods and the weight variations applied in the sensitivity analysis, CFRP emerges as the best option in 57% of cases. At the same time, STE is the top choice in 43% of cases. Traditional retrofit techniques, which consist of increasing the concrete section and using steel profiles, are widely used worldwide [15]. Applying U-jacketing reinforced  
Figure 7: Sensitivity analysis. (**a**) EDAS; (**b**) MABAC; (**c**) CODAS; (**d**) MARCOS. concrete sleeves to retrofit beams with shear deficiencies is an ongoing development within the scientific community to address key challenges, such as limited section increase. A group of researchers conducted an experimental study using thin layers of U-shaped reinforced concrete to retrofit shear-critical beams, evaluating the performance of these jackets [14]. Similarly, another group explored the effectiveness of U-shaped reinforced cementitious mortar liners for repairing damaged shear-critical beams [52]. In another study, they analyzed beams representing older construction practices with inadequate stirrup spacing, which leads to premature shear failure. They applied a three-sided coating method using thin sleeves of self-compacting reinforced concrete [56]. The retrofitting alternatives in this study focus on improving shear strength in reinforced concrete beams. However, concrete jackets allow the sections to behave similarly to conventional sections of the exact dimensions. A group of researchers analyzed the load-displacement curves and the corresponding ductilities, concluding that retrofitting reinforced concrete beams exhibits mechanical behavior comparable to and slightly better than ordinary reinforced concrete beams of the same size [57]. As for CFRP, significant improvements in ductility have been determined up to the point of lamina detachment [58]. Similarly, another group studied the retrofitting of shear-critical reinforced concrete beams using various FRP systems. It concluded that retrofitting improved shear capacity and transformed shear failure into more ductile flexural failure [59]. In addition, an experimental study examined the effects of steel plates attached to the web of the beam, either with adhesives or bolts, showing significant improvements in beam stiffness--by 29% and 42%, respectively--as well as more excellent ductility when more bottomless plates are used [46]. This study classified five retrofit alternatives based on coating techniques for jacketing beams with shear deficiencies. However, the literature highlights additional techniques that achieve the same retrofit objective. One such method is shear beam retrofit through external prestressing, where a restoring force is applied via externally placed, non-adhered tendons. This approach is known for its ease of application, cost-effectiveness, and straightforward maintenance [51; 60]. In recent years, ultra-high-performance concrete (UHPC) has been proposed to retrofit reinforced concrete structural elements. In beams, UHPC has been shown to prevent shear failure and enhance flexural performance, increasing strength by 40% to 125%, making it a promising emerging alternative [61].