# Decision Support Model for Allocating Maintenance Budgets for Bridges
## 4 Proposed Model
### Pilot Study and Development of the Questionnaire Survey
#### 4.2.2 Establishing the MAUT Curves
If the bridge scored 0, very dangerous, then its score is 1, although it may be excluded from maintenance prioritization and may instead be prioritized for replacement. \begin{table}
\begin{tabular}{c c c c c c c c} \hline  & \begin{tabular}{c} **Condition** \\ **Assessment** \\ \end{tabular} & **Bridge Age** & \begin{tabular}{c} **Bridge** \\ **Location** \\ \end{tabular} & \begin{tabular}{c} **History of** \\ **Maintenance** \\ \end{tabular} & \
\begin{tabular}{c} **Scheduled** \\ **Maintenance** \\ \end{tabular} &
\begin{tabular}{c} **Traffic** \\ **Volume** \\ \end{tabular} & **Total** \\ \hline R1 & 0.3057 & 0.0577 & 0.1784 & 0.0758 & 0.136 & 0.2464 & 1 \\ \hline R2 & 0.1509 & 0.0831 & 0.272 & 0.1219 & 0.1951 & 0.1771 & 1 \\ \hline R3 & 0.1809 & 0.0672 & 0.2088 & 0.0997 & 0.1425 & 0.301 & 1 \\ \hline R4 & 0.2519 & 0.182 & 0.2243 & 0.0708 & 0.0935 & 0.1776 & 1 \\ \hline R5 & 0.1758 & 0.1074 & 0.2622 & 0.1993 & 0.0808 & 0.1744 & 1 \\ \hline R6 & 0.235 & 0.1738 & 0.0797 & 0.1729 & 0.1401 & 0.1985 & 1 \\ \hline R7 & 0.2813 & 0.102 & 0.151 & 0.0803 & 0.0973 & 0.2881 & 1 \\ \hline R8 & 0.3614 & 0.2217 & 0.0607 & 0.1229 & 0.0932 & 0.1401 & 1 \\ \hline R9 & 0.3896 & 0.1452 & 0.0929 & 0.068 & 0.0938 & 0.2105 & 1 \\ \hline Median & 0.2519 & 0.1074 & 0.1784 & 0.0997 & 0.0973 & 0.1985 & 0.9331 \\ \hline Mean & 0.2592 & 0.1267 & 0.17 & 0.1124 & 0.1192 & 0.2126 & 1 \\ \hline Mode & 0.2519 & 0.1074 & 0.1784 & 0.0997 & 0.0973 & 0.1985 & 0.9331 \\ \hline SD & 0.0833 & 0.0568 & 0.0789 & 0.047 & 0.037 & 0.0548 & 0.3579 \\ \hline VAR & 0.0062 & 0.0029 & 0.0055 & 0.002 & 0.0012 & 0.0027 & 0.1281 \\ \hline \(\Sigma\)VAR & & & & 0.0204 & & & \\ \hline C\(\alpha\) & & & & 0.9456 & & & \\ \hline Weight & 25.9\% & 21.3\% & 17.0\% & 12.7\% & 11.9\% & 11.2\% & 100\% \\ \hline \end{tabular}
\end{table} 
Table 4: Criteria weights. Traffic Volume  
The amount of traffic passing over a bridge is represented by the Annual Average Daily Traffic (AADT). The experts preferred to use differential prioritization for the AADT. This means that the AADT for all of the bridges being prioritized for maintenance are classified: the bridge with the highest AADT receives the full score and the bridge with the lowest AADT receives a zero score. The bridges in between receive a score proportional to their AADT. According to the experts there are ongoing projects for traffic counting. Based on the findings of this project, the AADT can be determined for each bridge. In the meantime, the municipality may depend on the Average Daily Traffic (ADT) or the peak hour volume. Figure 2: MAUT curves for prioritization criteria. The location is categorized into four classes based on the traffic type and the load passing over the bridge in that location. The type of traffic in residential areas is lighter than any other location as traffic in that location is comprised of light vehicles, whereas trucks are prevented from entering these locations. Therefore, bridges located in a residential area have the least priority. The types of traffic passing over the bridges located in the commercial area are comparable to light trucks that are heavier than the first class. Thus, it receives a higher priority. The types of traffic using bridges in the industrial areas are heavier than the previous classes. Therefore, it receives a higher score. The types of traffic using bridges located in military/political areas are much heavier, which is also due to the importance of these locations to the government. The experts all agreed on this scale as they see it as representative of the bridge's locations in the study area. Most experts have recognized the age of the bridges as being 50 years old. Some of them indicated 100 years. The experts suggest that a bridge has the highest priority for maintenance at the age of 35 years on average. Older bridges are excluded from maintenance and are prioritized for replacement. The experts recommended both a linear and a parabolic relation between the age and the score.