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Abstract The stay cables and suspenders in service, which are composed of galvanized steel wires or strands, are usually exposed directly in air, or even in an acid rain environment if the outer sheath is damaged, posing severe safety hazards. In order to better evaluate the working conditions and the remaining life due to corrosion fatigue damage, and to provide a scientific basis for the detection, maintenance and replacement of cables and suspenders, the corrosion behaviors of steel strands exposed to acidic rain under alternating stress, static stress, and no stress, respectively, are modeled based on the experimental data. The results are based on the image corrosion feature analysis of steel strands at different corrosion times and operating conditions, and the corrosion fatigue behaviors indicate that the steel strands display different degrees of corrosion under different loading conditions. The results show that different loading conditions lead to different degrees of corrosion in the steel strands. The samples’ surface images and corrosion damage continuously
change as the corrosion time increases. Given the same corrosion time, the degree of corrosion reaches the highest in samples subjected to alternating stress, followed by that in samples under static stress. Unstressed samples exhibit the lowest degree of corrosion. No significant changes occur in the samples when the corrosion time is 120 h–360 h, regardless of the type of stress they are subjected to. This indicates that pitting has little effect on the force-bearing capacity of steel strands during pit nucleation and expansion. However, substantial decreases up to 40% in the fracture strength occur in the samples subjected to alternating loads in the case of 720-h-corrosion, compared with the corrosion-free specimens. This research also shows that corrosion image can reflect the microscopic damage behavior of steel strand. Mapping relationships exist among the gray scale distribution of corrosion image, the microscopic damage and the bearing capacity.
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Received: 22 September 2017
Published: 08 February 2018
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2018, Vol. 39 
