Research on bending capacity of corroded RC beams under fatigue loading

Based on large number of fatigue loadings on corroded R.C. structures and small number of study on its mechanical property, fatigue bending capacity tests of one normal R.C. beam and five R.C. beams by accelerated corrosion under fatigue loadings are discussed in this paper. Its properties, such as span center deflection and maximum crack width, are researched by the influence of stress ratio (0.1, 0.3, and 0.5) and corrosion rate (0.00%, 0.59%, and 1.94%). The relationship between stress ratio and mid-span displacement is linear. And by No. of cycles, the smaller the stress ratio is, the larger the increase of mid-span displacement is. The influence of stress ratio on maximum crack width of specimens is obvious, and the larger the stress ratio is, the longer the fatigue life is. It has effect on the load carrying capacity of specimens directly. The mid-span deflection of specimens which corrosion rate is 0.59% is smaller than that of normal specimens under the static loads and the fatigue loads, and the maximum crack width of corrosion ratio 0.59% specimens is larger than that of non-corrosion specimens. The relationship between the strains E of corroded re-bars and the fatigue life N of R.C. beams is obtained, and the relationship is inverse ratio and the corrosion of re-bars is a sensitive factor to the damage and the fatigue life.