Analysis of Monitoring Priorities for Long-Span Suspension Bridges in Complex Environments

Abstract

Structural Health Monitoring (SHM) systems for mega-bridges play a critical role in modal identification, damage detection, and safety assessment, providing essential information for decision-making. Despite significant advancements in SHM technology for mega-bridges, monitoring these structures in highly complex environments still requires continuous improvement. For the Moon Bay Bridge, which exists in a particularly complex environment, two primary monitoring focuses have been identified: real-time GNSS monitoring for the high-intensity canyon suspension bridge and the impact of temperature variations on structural responses and sensor performance. The analysis focuses on structural responses such as the displacement at the top of the pylon, elevation changes, and anchor displacements to obtain comprehensive deformation information. The research results indicate that in the GNSS monitoring data, the displacement at the top of the pylon on the Yunnan side and the displacement of the upstream and downstream anchors on the Yunnan side were relatively stable, while the vertical elevation changes fluctuated significantly. This fluctuation is attributed to the settlement of the tunnel-anchored structure caused by the advance excavation of the tunnel, with minimal disturbance to the anchor plug from subsequent tunneling. Temperature has a minor impact on the horizontal and vertical angles at the beam ends but significantly affects the longitudinal displacement and bearing displacement at the beam ends. Temperature changes greatly influence the cable forces of the end suspender cables, while the impact on other suspender cables is minimal. To minimize the interference of complex environmental factors on monitoring results, enhance data accuracy and reliability, and ensure the stability and safety of the bridge, special attention must be given to the effect of temperature changes on the end suspender cables.