# Digital Twin Framework for Road Infrastructure Management
## 6 Implementation Scenario--Case Study  
This section aims to demonstrate how the proposed DT framework for road infrastructure management functions, specifically for bridges. Every country establishes an organization or agency responsible for coordinating activities related to road infrastructure management to ensure proper maintenance and prevent deterioration of road conditions. \begin{table}
\begin{tabular}{c c c c} \hline \multicolumn{2}{c}{**ISO 23247-2 DT Reference Framework**} & \multicolumn{2}{c}{**Proposed DT Framework**} \\ \hline DT Core Subdomain & Specific Functional Entities & Relevant Functional Elements & Corresponding Layers \\ \hline \multirow{4}{*}{Operation and Management} & Digital Modeling & All models (GIS, BIM, CIM, etc.) & DM \\ \cline{2-4}  & Presentation and & Visualization & DA \\  & Representation & Synchronization (control) & DA \\ \cline{2-4}  & Synchronization & Updating and management & \\  & Maintenance & (control) & DA \\ \hline \multirow{4}{*}{Application and Service} & Simulation & Simulation & DA \\ \cline{2-4}  & & Road asset management, & \\ \cline{1-1}  & Analytics Service & transportation management, & \\ \cline{1-1}  & evaluation, monitoring, alert, & & DA \\ \cline{1-1}  & & etc. & \\ \cline{1-1} \cline{2-4}  & Reporting & Reporting (alert) & DA \\ \hline Application Support & Maintenance strategy & DA \\ \hline \end{tabular}
\end{table} 
Table 6: Comparison between the main functional elements of the ISO 23247-2 reference model and the proposed model. Road management systems can be implemented to effectively address these needs and manage public assets efficiently. Bridge management systems (BMS) are a key component of such systems, and a typical BMS includes inspection, structural health monitoring, and rehabilitation. However, several challenges currently faced by BMS are outlined below [56]:  
* Lack of standardization in bridge infrastructure management;
* Absence of geometric representation of bridges within BMS;
* Continued reliance on traditional paper-based methods for maintenance activities;
* Limited remote or online access to BMS, primarily restricted to desktop computers;
* Lack of a whole lifecycle-based information management approach for bridges;
* Insufficient automated bridge assessments utilizing AI, BIM, and FEM models and GIS. Figure 11 illustrates a typical workflow for bridge management activities encompassed by BMS. This workflow begins with data collection and inspection, progressing through condition assessment, prediction, and budget allocation and planning, ultimately leading to decision-making in bridge management. This case study will illustrate how these fundamental steps can be integrated into the proposed DT road management framework to address the identified issues. The implementation is structured through five proposed layers, and Figure 12 demonstrates the application of the bridge DT framework with brief names for each layer. (1) Data acquisition and transmission layer  
Bridges are the primary data source and service object for BMS, as well as for road bridge DTs. In this case, the main objective is to support decision-making in bridge management by prioritizing and comparing various maintenance alternatives for optimal budget allocation and planning. This process involves predicting the future condition of bridges based on the assessment of their current state and modeling bridge degradation. Furthermore, additional functions offered by DTs can be integrated to address the challenges faced by BMS. Generally, bridges consist of multiple elements categorized into superstructure and substructure. These categories can be further broken down into sub-units and sub-parts (e.g., towers, beams, piers, decks, cables) depending on the maintenance goals. For superstructure maintenance, inventory and condition data related to the bridge deck (slab), pavement, girders, or beams can be collected.