Development of a Cable Assessment Method Based on Phase Space Trajectory for Cable-Stayed Bridge Under Moving Loads

This study emphasized the importance of structural health monitoring for assessing cable-stayed bridges, which are vulnerable to damage, particularly fatigue and corrosion in their cables. Cable tension has been evaluated using natural frequency analysis and a widely adopted vibration-based approach. These conventional methods often required traffic disruptions or even completed bridge closures. This paper proposed a damage detection method for cable-stayed bridge cables under moving loads at low speeds, which minimizes traffic disruptions. This research focused on the phase space method and deck displacement responses in the time domain. A benchmark cable-stayed bridge with a concrete deck and pylon was studied. Seventeen damage scenarios were defined, and two damage indices, change in phase space topology and Mahalanobis distance, were used to detect cable damage. The effectiveness of the phase space-based method for damage detection was validated on two steel cable-stayed bridges with different configurations. The results demonstrated that changes in phase space topology were highly effective at detecting one or two damaged cables. This method required only displacement data at cable-deck connection points, eliminating the need for sensors along the entire deck. This damage detection approach faced challenges with back-stay cables and cables near the pylons.