A digital twin prototype for 3D structural health monitoring and simulation-based diagnosis of urban bridges

With the increasing complexity of urban transportation infrastructure, bridges, as critical nodes, play a direct role in determining urban operational efficiency and public safety. Traditional bridge management approaches face challenges such as delayed monitoring, coarse diagnostics, and untimely maintenance responses, underscoring the need for intelligent technologies for lifecycle-oriented management. This study proposes and implements a Digital Twin-based 3D structural health monitoring and simulation-based diagnosis prototype system for bridges, which effectively addresses the aforementioned issues. The system integrates key technologies including high-precision 3D modeling, BIM-GIS unified representation, IoT-based sensing, real-time data stream access, component-level data mapping, and visual analytics to construct a closed-loop architecture encompassing perception, modeling, analysis, and feedback. Covering essential processes such as data acquisition, model rendering, condition assessment, and interactive response, the system was validated through a case study of the Shennan-Xinzhou Overpass in Shenzhen. It demonstrated the implementation of a digital bridge model, real-time sensor data integration, component-level condition visualization, and anomaly diagnosis. Experimental results show that the system can dynamically map key health indicators—such as temperature, displacement, strain, and acceleration—and enable simulation-based structural diagnosis, demonstrating robust adaptability and stable performance. This study presents a viable paradigm for applying Digital Twin technology in urban bridge management, revealing its great potential in facility sensing, risk evaluation, and maintenance support. Future work may extend the system toward multi-bridge collaborative monitoring, cross-scenario integration, and intelligent decision support, offering a solid foundation for smart transportation infrastructure management in urban settings.