Fatigue sensibility of R/C secondary elements of bridges

The influence of fatigue may be an important but not usually contemplated aspect on the behaviour of some components of concrete structures. Here a study on the bridge approach slabs is presented. It is shown how the cyclic load causes a progressive deterioration of the compression zone of concrete and its contribution in the tensile chord between cracks. The increase of deflections and crack widths along the fatigue life is observed experimentally, under maximum and minimum loads. The growth of the remnant values of these variables evidences the important irreversibility of the fatigue degradation.