PSI - Issue 78

Ataklti Gebrehiwet Gebrekidan et al. / Procedia Structural Integrity 78 (2026) 1665–1672

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variables. Conversely, from a simplified perspective, specialist design knowledge, installation skills and foundation interventions were assigned lower weights. The weight values for each decision matrix are summarised in Table 1.

J S J

SI

J S J

SI

. . ormali ed erformances r i . .

. . . ormali ed erformances r i .

(a Low a ard

( igh a ard

Figure 4: Normalised decision matrix values of DVs (Ci) for the four alternatives considered in the MCDM assessment.

Table 1: Summary of the combination of decision matrices and the weight assigned to the DVs.

Decision Variables [DVs]

Decision matrix (D)

C1

C2

C3

C4

C5

C6

C7

C8 C9

C10

Comb1 Comb2 Comb1 Comb2

0.10 0.10 0.18 0.22 0.19 0.12 0.10 -

-

-

Low Hazard

0.05 0.05 0.10 0.18 0.16 0.05 0.05 0.16 0.09 0.11

0.17 0.15 0.15 0.17 0.17 0.11 0.8

-

-

-

High Hazard

0.11 0.09 0.10 0.13 0.11 0.07 0.06 0.12 0.10 0.11

5.3. Ranking of retrofitting interventions The relative closeness of each alternative to the ideal retrofit solution, which is the parameter used to establish the preferential ranking, was obtained from the MCDM analysis and is reported in Figure 5. This relative closeness is the parameter used to establish the preferential ranking, and its values range from 0 to 1, with 1 indicating the ‘ideal’ solution. In the low hazard site, in Comb1, i.e., when EI is excluded from the analysis, RC-J is ranked as the top alternative with a large distance over the second-ranked FRP-C (12% difference in terms of relative closeness), while SI is ranked last. The preference for RC-J is due to its low installation cost, despite its relatively poor seismic performance. In contrast, SI is the least preferred option due to its high installation and maintenance costs, despite its best seismic performance, and the reduced importance assigned to seismic-related DVs in this combination. In case of Comb2, it is evident that incorporating EIs into the MCDM framework influences the preferential ranking. S-J and SI emerge as the first and second preferred alternatives respectively, while RC-J drops to third place. This shift in RC J’s ranking is linked to its poor seismic performance, which increases the EI -associated repair actions.

Figure 5: Relative closeness to the ideal solution of the retrofit alternatives under different combinations of DVs.