## 4 A Study on the Application of Nine Bridges in the Proposed Prioritization Model
### Select Bridges with Prioritized Models  
To select the bridges for applying the maintenance prioritization model, nine bridges in the Gyeongsang region of South Korea, for which detailed safety inspection reports are openly available from Korea Expressway Corporation, were chosen. These bridges were selected based on the availability and completeness of their inspection records, as well as their diversity in terms of structural type, construction year, traffic volume, and safety condition. These selected bridges were characterized by their construction year, design load, seismic design status, integrated safety rating, Average Annual Daily Traffic (AADT), secondary damage factors, facility type, and the number of bidirectional lanes. These data are presented in Table 10, and the nine bridges were selected as the target for the PI application. Photographic views of these bridges are provided in Figure 4.  
Figure 4: Photographic overview of bridges applied in the model [31].  
The construction years of the bridges range from 1995 to 2007, with some having been in use for up to 29 years. Although all bridges are designed to support the same load (DB-24), none have been subjected to seismic design considerations. The overall safety ratings include three bridges with an A grade, five with a B grade, and one with a C grade. The AADT values vary from 24,676 to 110,851. Additionally, all bridges belong to Facility Type 1, and the number of bidirectional lanes ranges from 2 to 10. The nine bridges feature various superstructure types, including steel box girder, PSC box girder, and PSC beam. The allocation of safety ratings based on structural types as determined through the detailed safety inspection reports is presented in Table 11.  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Bridge** & **Year of Complete-Category** & **Length** & **Maximum** & **Design** & **Seismic** & **Total** & **Safety** & **AADT** & **Secondary** & **Facility** & **Number** \\ A & 1995 & 595.1 & 30 & DB-24 & N & C & 54,869 & Bridge & Type 1 & 4 \\ \hline B & 2003 & 800 & 50 & DB-24 & N & B & 110,851 & River & Type 1 & 8 \\ (highway) & 2005 & 840 & 60 & DB-24 & N & B & 24,676 & Road & Type 1 & 4 \\ \hline D & 1995 & 400 & 50 & DB-24 & N & B & 37,154 & River & Type 1 & 4 \\ (highway) & 2007 & 260.4 & 60 & DB-24 & N & A & 54,319 & Bridge & Type 1 & 4 \\ (highway) & 2007 & 255.4 & 60 & DB-24 & N & A & 54,319 & Bridge & Type 1 & 4 \\ (highway) & 2007 & 120.2 & 50 & DB-24 & N & A & 54,319 & Bridge & Type 1 & 1 \\ (highway) & 2007 & 490.7 & 50 & DB-24 & N & B & 54,319 & River & Type 1 & 2 \\ (highway) & 2005 & 500 & 50 & DB-24 & N & B & 25,304 & River & Type 1 & 2 \\ \hline \hline \end{tabular}
\end{table}
Table 10: Data on nine bridges applying the maintenance prioritization model [2].  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Bridge** & **Facility** & **Deck** & **Girder** & **Abutment** & **Pier** & \
\begin{tabular}{c} **Bearing** \\ **Support** \\ \end{tabular} &
\begin{tabular}{c} **Expansion** \\ **Joint** \\ \end{tabular} \\ \hline A & PSC beam & D & E & B & C & C \\ \hline B & Steel box girder & B & B & B & B & B \\ \hline C & PSC box girder & C & C & B & C & B & B \\ \hline D & PSC box girder & B & B & C & C & B & C \\ \hline E & Steel box girder & C & B & C & C & B & C \\ \hline F & Steel box girder & B & B & C & C & B & C \\ \hline G & Steel box girder & B & B & C & C & B & C \\ \hline H & PSC box girder & B & B & C & C & B & C \\ \hline I & Steel box girder & C & C & B & B & B & C \\ \hline \hline \end{tabular}
\end{table}
Table 11: Safety grade by location of the member.