Performance monitoring of assembled beam bridges using displacement spectrum similarity measure

The assembled beam bridge is a widespread construction, with transverse connections uniting precast beams to jointly support loads. These connections, while crucial, are the most vulnerable elements in such structures. Therefore, the development of an effective index for continuous condition assessment remains the cornerstone of structural health monitoring. The Displacement Spectrum Similarity Measure index, as per ideal conditions in numerical simulations, has shown insensitivity to short-term vehicle loads and sensitivity to transverse connection stiffness. This study extends its scope to address potential real-world interference factors, including measurement errors and deck pavement damage. Specifically, we introduce Gaussian white noise to simulate measurement errors and incorporate additional vehicle loads to emulate the impact of pavement damage. Numerical simulations confirm the robustness of the index against these challenges. Additionally, a real-time index extraction scheme is proposed and implemented on an operational bridge. The results reveal a close alignment between the transverse connection condition assessed by the index and the findings obtained through on-site surveys, thereby substantiating the viability and effectiveness of the index for real-world engineering contexts.