# Performance-Based Ranking of Existing Road Bridges
## 2 Assessment Procedure
### System Level  
Furthermore, after the disclosure of indicators at the level of each component (\(1<\infty<n\)), the Key Performance Indicators (_KPI_) of the overall bridge as a system are proposed by [PERSON] et al. [48] as maximum values among the component indicators. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Bridge Subsystem** & **Individual Part** & **Component** & \(I_{SS,CO}\) & \(I_{TS,CO}\) & \(I_{D,CO}\) \\ \hline \multirow{8}{*}{Substructure} & & BEARING & 2 & 1 & 1 \\ \cline{2-5}  & & BEARING PAD & 2 & 1 & 1 \\ \cline{2-5}  & & HEAD BEAM & 3 & 1 & 1 \\ \cline{2-5}  & & PILLAR, PIER & 3 & 1 & 1 \\ \cline{2-5}  & & ABUTMENT WALL & 2 & 4 & 1 \\ \cline{2-5}  & & FOUNDATION & 3 & 1 & 1 \\ \cline{2-5}  & & EMBANKMENT CONE & 1 & 3 & 2 \\ \cline{2-5}  & & BEARING & 2 & 1 & 1 \\ \cline{2-5}  & & BEARING PAD & 2 & 1 & 1 \\ \cline{2-5}  & & HEAD BEAM & 3 & 1 & 1 \\ \cline{2-5}  & & PILLAR, PIER & 3 & 1 & 1 \\ \cline{2-5}  & & LINING & 2 & 1 & 2 \\ \cline{2-5}  & & FOUNDATION & 3 & 1 & 1 \\ \cline{2-5}  & & BARRIER & 1 & 1 & 2 \\ \hline \multirow{8}{*}{DRAINAAGE} & SURFACE & CURB & 1 & 3 & 2 \\ \cline{2-5}  & DRAINAGE & WATER INLET (DRAIN) & 1 & 3 & 2 \\ \cline{2-5}  & & INTERCEPTING PIPE & 1 & 3 & 2 \\ \cline{2-5}  & & MAIN SEWER & 1 & 3 & 1 \\ \cline{1-1} \cline{2-5}  & & SHAFT & 1 & 3 & 1 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: _Cont._Bridge structural safety is indicated with:  
\[KPI_{SS,SY}=\underset{1\leq CO\leq n}{max}PI_{SS,CO} \tag{8}\]  
Bridge traffic safety is indicated with:  
\[KPI_{TS,SY}=\underset{1\leq CO\leq n}{max}PI_{TS,CO} \tag{9}\]  
Bridge durability is indicated with:  
\[KPI_{D,SY}=\underset{1\leq CO\leq n}{max}PI_{D,CO} \tag{10}\]  
Bridge condition assessment is indicated with:  
\[KPI_{BCA,SY}=\underset{1\leq CO\leq n}{max}PI_{BCA,CO} \tag{11}\]  
An additional key performance indicator shows the bridge availability \(KPI_{AV,SY}\) in case of necessary restrictive measures related to the bridge condition assessment. The quantitative scale of the values of the \(KPI_{AV,SY}\) is presented in Table 4, depending on the traffic type and the expected traffic restrictions. If among the previous _KPIs_ (Equations (8)-(11)), the one related to traffic safety \(KPI_{TS,SY}\) is the most relevant (onerous, the highest value), the assessment of \(KPI_{AV,SY}\) refers to the expected measures in the areas of the bridge reserved for traffic (and must not be chosen with a value of 1). If other _KPIs_ have the greatest influence on maintenance or repair measures, \(KPI_{AV,SY}\) should be carefully selected considering the expected and necessary traffic restrictions. In this sense, the evaluation of separate maximum indicators for each part of the structure may be useful. Equations (8)-(11) should be used, but not for a complete bridge structure, but for the components that make up each individual part IP, (\(KPI_{SS,IP}\), \(KPI_{TS,IP}\), \(KPI_{D,IP}\), \(KPI_{BCA,IP}\)). For example, for the girder structure (see Table 3) only roadway slab, cantilever, main longitudinal girders, secondary longitudinal girders, and cross girders are considered. \begin{table}
\begin{tabular}{l l} \hline \hline
**Road Traffic** & \(KPI_{AV,SY,road}\) \\ \hline Traffic flow on the bridge is flowing smoothly, without the need for slowing down & 1 \\ \hline Traffic flow is slowed down and jammed due to bridge pavement condition; both & 2 \\ lanes are functioning & \\ \hline Traffic from both directions is in the same lane, along with speed restrictions & 3 \\ \hline Traffic restrictions for heavy vehicles, trucks, etc. & 4 \\ \hline A bridge is closed for traffic & 5 \\ \hline
**Railway (Train, Trams) Traffic** & \(KPI_{AV,SY,rail}\) \\ \hline Railroad traffic is flowing smoothly & 1 \\ \hline Traffic is slowed down due to rails conditions & 2 \\ \hline Traffic is flowing only on one rail track-separately from both directions & 3 \\ \hline Traffic restriction for trans/trains & 4 \\ \hline A bridge is closed for all the rail tracks & 5 \\ \hline \hline \end{tabular}
\end{table}