## 4 A Study on the Application of Nine Bridges in the Proposed Prioritization Model
### Data-Based Bridge Maintenance Priorities Analysis  
To validate the results of the Bridge Maintenance Priority analysis, as shown in Tables 12 and 13, a methodology was applied to calculate the Bridge Health Index (BHI) score by combining the BMP and PI scores. This evaluation method comprehensively  
Figure 8: Distribution chart based on Bridge Health Index (BHI) score results. Figure 7: Distribution chart based on Priority Index (PI) score results. reflects the structural and operational conditions of each bridge, incorporating the factors of risk, criticality, and comparison. By utilizing detailed safety inspection reports, including the PI score, the structural characteristics and safety status of each bridge can be accurately assessed, resulting in a reliable prioritization for maintenance. Among the eight indices in the BMP score, the years of use and overall safety grade were found to have the greatest influence on prioritization in the risk score section. As time passes, the years of use naturally lead to aging, which indicates a decline in structural safety. The accumulation of physical and chemical factors, such as material fatigue, corrosion, deterioration, and repeated loads, can cause significant maintenance issues for the bridge. Therefore, the years of use have a significant impact, and as shown in Table 3, they account for a weight of 0.3 in the risk score impact factor. Accordingly, as shown in Table 12, bridges with greater years of use received higher risk scores. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Bridge** & **BMP Score** & **PI Score** & **BHI Score** \\  & **(Rank)** & **(Rank)** & **(Rank)** \\ \hline A & 0.1246 & 0.138 & 0.2626 \\  & (1) & (1) & (1) \\ \hline B & 0.1156 & 0.0539 & 0.1694 \\  & (2) & (9) & (3) \\ \hline C & 0.0594 & 0.0863 & 0.1457 \\  & (6) & (2) & (6) \\ \hline D & 0.0490 & 0.0698 & 0.1189 \\  & (7) & (8) & (9) \\ \hline E & 0.0895 & 0.0832 & 0.1728 \\  & (3) & (3) & (2) \\ \hline F & 0.0741 & 0.0741 & 0.1481 \\  & (4) & (5) & (4) \\ \hline G & 0.0741 & 0.0741 & 0.1481 \\  & (4) & (5) & (4) \\ \hline H & 0.0475 & 0.0741 & 0.1216 \\  & (8) & (5) & (7) \\ \hline I & 0.0389 & 0.0826 & 0.1215 \\  & (9) & (4) & (8) \\ \hline \hline \end{tabular}
\end{table} 
Table 13: Maintenance priority selection results. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Bridge** & **Risk Score** & **Criticality Score** & **Comparison Score** \\ \hline A & 0.341 & 0.63 & 0.58 \\ \hline B & 0.313 & 0.52 & 0.71 \\ \hline C & 0.277 & 0.37 & 0.58 \\ \hline D & 0.313 & 0.27 & 0.58 \\ \hline E & 0.245 & 0.63 & 0.58 \\ \hline F & 0.245 & 0.63 & 0.48 \\ \hline G & 0.245 & 0.63 & 0.48 \\ \hline H & 0.277 &The overall safety grade index carries the highest weight of 0.4 in the risk score impact factor. It is an important indicator that assesses not only the structural condition of the bridge but also environmental and operational factors, providing a comprehensive evaluation of safety and efficiency. This allows for the identification of risk factors and supports the development of efficient maintenance plans, minimizing social and economic impacts. Therefore, the overall safety grade is a key determinant in prioritizing maintenance. Similarly to the years of use, bridges with higher scores in the overall safety grade also received higher risk scores. With regard to the design load and the presence of seismic design, the nine bridges had identical values for both factors. Consequently, these factors did not significantly impact the risk score. The AADT, secondary damage potential, and number of lanes in the criticality and comparison sections also significantly influence a bridge's BMP score. In the criticality section, a higher AADT indicates a higher frequency of vehicle use on the bridge, and as a result, secondary damage to the bridge cannot be overlooked. This increases the urgency for maintenance to prevent secondary damage. The number of lanes represents the traffic capacity of the bridge, and the more lanes there are, the higher the importance of the bridge.