Test method of simulating erosion and fatigue load of prefabricated bridge joints

In many cases, bridge structures bear the long-term combined action of erosion and fatigue load, which may result in coupled effects of damage and even destruction. To reveal the complex mechanism of the long-term coupled effect, experimental simulation is necessary, in which the long-term combined action of erosion and fatigue load is needed to be applied for the specimens. So far, the main difficulty in the long-term simulation of the combined action is to conveniently apply the long-term fatigue load on multi-specimens. To solve this difficulty, the authors have invented a mechanical fatigue machine which is suitable for long-term fatigue loading. By using this machine, the long-term coupled effects of erosion/corrosion and fatigue of the top flanges of prefabricated box girder bridge joints will be studied. So far, the testing program has been drawn up. In the experiment, twelve uniform prepressed specimens of joint were acted by uniform tensile fatigue load and wet-dry cycle erosion of salt solution simultaneously. The twelve specimens were separated into three groups with different tensile stress amplitudes. Thus, there are four specimens in each group. The combined action time of the four specimens in each group are 90d, 180d, 270d and 360d. The detailed method and program are introduced in this paper.