Fatigue cumulative damage evaluation based on smart stay cables

Stay cables are one of the most critical structural components of cable-stayed bridge. However, stay cables readily suffer from fatigue damage, corrosion damage and their coupled effects. Thus, health monitoring of stay cables is important for ensuring the integrity and safety of a bridge. The application of the smart stay cables on the Tianjin Yonghe Bridge is demonstrated and the vehicle fatigue load effects smart stay cables are evaluated based on field monitoring data. Secondly, based on fatigue test results of corroded wires obtained from dissection of actual parallel wire cables which were used on Tianjin Yonghe cable-stayed bridge, the fatigue properties of corroded cable are investigated by the method of Monte Cazlo simulation. The results of fatigue lives and corrosion degree of corroded wire are presented. Comparisons between the original design information and fatigue test results, it can be seen that corrosions make the fatigue lives of wires decreasing sharply and the cable fatigue lives are controlled by a small fraction of the cable wires with the shortest fatigue lives. Finally, based on the simulated S-N curves of cable and Miner's law, the fatigue cumulative damages of cables in reference periods are evaluated.