محمدصادق ايوبي راد

Vibration-based structural health monitoring (SHM) is essential for eva‎luating the integrity of large civil infrastructure systems. The development of accurate finite element (FE) models that effectively capture full-scale structural dynamics is critical to successful vibration-based SHM implementation. This study presents a comprehensive framework for numerical model updating, railway truss bridge assessment, and damage detection that integrates operational modal analysis, sensitivity-based numerical model updating, and train-track-bridge interaction (TTBI) dynamics. For modal identification, this research employed covariance-driven stochastic subspace identification (Cov-SSI) coupled with hierarchical density-based spatial clustering of applications with noise (HDBSCAN). Results demonstrated that sensitivity-based numerical model updating significantly enhanced model accuracy, substantially reducing modal frequency errors. During dynamic validation, vertical train-track-bridge interaction was modeled and validated against field measurements. Comparison of acceleration time histories revealed superior agreement between the TTBI dynamic interaction approach and experimental data compared to conventional moving load models. The numerical model was further validated through static load testing using a GT26 locomotive. Various damage scenarios were then applied to the validated model, with local damage simulated through stiffness reduction via 5%, 10%, 20%, and 40% decreases in elastic modulus for 20-centimeter elements across different sections of cross beams and southern chord members. Damage indices were calculated using temporal autoregressive modeling, and performance was eva‎luated across different train speeds. Analysis of these indices successfully identified damage presence, location, and severity within the structure. This research framework provides a robust numerical platform for comprehensive structural fault detection in railway bridge systems, offering significant potential for practical SHM applications in critical infrastructure assessment.

شناسايي مودال , اندركنش قطار-خط-پل , كرنش , پل خرپايي , پاسخ شتاب

Modal Identification , Train–Track–Bridge Interaction , Strain , Truss Bridge , Acceleration Response

Mohammad Sadegh Ayubirad

Shervan Ataei