# A Decision Concept to the Historic Pedestrian Bridges Recovery Planning
## 5 Conclusions  
Historic pedestrian bridges are a key asset of cultural and socio-economical aspects of a city or region. The research aim was to propose a decision concept that will assist and improve decisions for final policy and decision makers, which is in this case was the Department of Conservatory in Split, in planning of the recovery of historic pedestrian bridges. A total of four stakeholders' groups were involved in the problem solving and creating the goal hierarchy structure. Planning of the rehabilitation of historic pedestrian bridges is an ill-structured problem and a compound process of decision-making that requires qualitative and quantitative methodology using adequate decision tools. A multicriteria decision-making analysis is proposed for this problematic because of the numerous mutually conflicted criteria and stakeholders involved in the process. The technique of AHP method is used to determine relative importance of each objective and criterion. Furthermore, defined criteria are used to evaluate bridges, and criteria weights are calculated for the further procedure. The approach of evidential reasoning is introduced to establish the evaluation ratings of the bridges. Each decision group defined its ratings of bridges according to each criterion. Ratings are determined by the proposed interval numbers instead of the crisp values. Finally, the aggregated decision matrix of ratings in the form of the belief matrix is designed. Furthermore, by the TOPSIS method a complete priority ranking of the historic pedestrian bridges is provided, calculating the Euclidian distance of each alternative from the ideal and anti-ideal solution and relative closeness index. Hereby, bridges with the smallest relative closeness are considered with the highest priority for the rehabilitation. The proposed decision concept is then tested to verify that the approach can be used in an engineering practice. Nine bridges were analyzed according to the defined eleven criteria. Kastilac bridge (B1) was ranked first with a closeness coefficient of 0.446 and the bridge by Castle Vitturi (B3) was ranked last with a coefficient value of 0.626. This results presents the objectivity and reality of the evaluated ratings, because the ranking of these bridges fits with the current condition of these bridges, and hence the planning schedule of their need for the rehabilitation. \begin{table}
\begin{tabular}{c c} \hline \hline
**Methodology** & **Priority Ranking** \\ \hline AHP & B6; B8; B7; B5; B1; B9; B3; B2; B4 \\ TOPSIS & B5; B7; B6; B8; B1; B9; B2; B3; B4 \\ AHP-TOPSIS & B8; B9; B1; B7; B5; B4; B6; B3; B2 \\ AHP-evidential reasoning-TOPSIS & B1; B9; B8; B7; B4; B5; B6; B2; B3 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Comparison of the proposed approach with other studies. After the above mentioned, the model of decision concept proved to be useful and supportive when it comes to the decision-making of historic pedestrian bridges recovery planning. Since the new model is flexible and easy to understand, it can be applied to other historic buildings in terms of recovery planning with the small changes (if necessary) in the model, especially in the goal hierarchy structure. Therefore, the proposed methodology would be upgraded with defined relevant criteria and scenarios to assess historic objects for the recovery projects. In summary, the proposed decision concept, based on the combination of three multicriteria methods, enables reliable support for the priority ranking of objects for the activity of remediation, according to the deterioration condition of pedestrian bridges. Therefore, the concept does not provide security only to project experts and stakeholders, but can also be introduced as an easy and fast learning tool for new experts. It can be an effective and useful approach to the strategies optimization undertaken by local and regional authorities, to resist increasing deterioration on historic pedestrian bridges. Conceptualization, K.R., J.K.P. and N.J.; methodology, K.R., J.K.P.