PSI - Issue 84

Antonio Sannino et al. / Procedia Structural Integrity 84 (2026) 890–897

894

The 3D point cloud data serves as a foundational resource for various advanced analyses crucial to tunnel inspection and maintenance. These high-fidelity models offer engineers a comprehensive view of the tunnel's condition, streamlining decision-making and enabling precise planning for repairs or upgrades. The surveys are stored in the cloud platform and are accessible to all users, including inspectors, engineers, and contractors. The captured raw point cloud data is processed using ARGO specialized software, which plays a key role in refining the model. This software filters out any noise or unwanted data, aligns the scans, and stitches them together to form a unified and coherent 3D-model of the tunnel. The point cloud data is securely stored in a cloud-based platform, ensuring centralized access and seamless collaboration across various stakeholders. This approach eliminates the need for cumbersome local storage solutions and facilitates real-time data sharing. Once the 3D-model has been prepared, it is converted into 2D images using a transformation module that enables the unrolling of the cylindrical tunnel onto a flat plane (Zhang et al., 2022). These 2D projections, shown in Figure 4, provide detailed visuals that support inspection reports for engineers and stakeholders, while also offering plan and elevation views that assist inspectors during in-situ assessments. The 3D-model in in Figure 5 serves also as a powerful visualization tool, enabling the integration and display of critical information such as the CdA. Attention classes categorize areas of the tunnel based on their need for inspection, providing a visual prioritization map.

Fig. 4. Example of 2D projection with defects annotation

2.3. Risk-based inspection approach

A key feature of ARGO is its ability to schedule inspections in compliance with regulatory guidelines and risk based assessments. Regular inspections are essential for identifying potential structural issues before they become critical, and ARGO automates the scheduling process according on each tunnel's attention class. By leveraging risk-based assessments, ARGO prioritizes inspections for tunnels with higher risk factors (CdA) according to Italian guidelines frequencies. This ensures that tunnels with a higher preliminary risk evaluation are inspected on time, thereby reducing structural risk. The system handles 597 highway tunnels, performing 2,500 site inspections over the year, including initial, ordinary, detailed and extraordinary inspections. Additionally, ARGO tracks the inspected segments over time, providing traceability of information and maintaining a comprehensive inspection history for each tunnel.