Design and Research on a Digital Twin Monitoring System for Mountainous Suspension Bridges Based on MBSE

To address the complex service environment of mountainous long-span suspension bridges, the insufficient virtual–real integration of existing monitoring systems, and the lack of a systematic design method, this study takes the Lugu Lake Bridge as a case and conducts safety monitoring system design by combining model-based systems engineering (MBSE) and digital twin technology. SysML is employed to construct the full modeling chain spanning system requirements, functions, logic, and physical architecture. The 1:150-scale physical model is innovatively embedded as a built-in verification link throughout the entire MBSE workflow, whereby a five-layer digital twin monitoring system architecture is established. A 1:150-scale physical model is constructed and tested under static, temperature, and dynamic loading conditions. The results show that the response errors at key measuring points are generally within 7%. Although relatively large deviations exist at a few individual measuring points, they have no significant impact on the overall accuracy level, and the dynamic characteristics agree well with the simulation results. A lightweight digital twin monitoring system is developed to enable multi-source data access, three-dimensional virtual–real mapping, and threshold-based warning, with an accuracy evaluation and updating mechanism for the digital twin model established. The research results can provide a reference for the design and engineering application of digital twin monitoring systems for mountainous suspension bridges.