Experimental study on fatigue performance of corroded highway bridges based on vehicle loading
Niu Ditao1,2 Miao Yuanyao1
1. State Key Laboratory of Green Building in Western China, Xi′an 710055, China;
2. Xi′an University of Architecture and Technology, Xi′an 710055, China
Abstract：Wet corroded sand specimens were used to obtain corroded reinforced concrete specimens. Targeted selection and the vehicle under the load of the bridge and the actual fatigue stress level. Through the bending fatigue test of eight corroded RC beams, the fatigue failure mode and the influence of the stress level and corrosion rate on the fatigue behavior of corroded RC beams are analyzed. The experimental results show that the fatigue failure model of the corroded beams is mainly the brittle fracture of the main ribs. Under the stress level of design, the fatigue load meets the requirements of 2 million times. Under the actual stress level of bridge, the average fatigue life of un-corroded test beam is reduced by 6.71% compared with the normal value. The fatigue life of the test beam with more serious corrosion is reduced by 13.57% compared with the standard value, and the fatigue life is reduced by 42.54% compared with the un-eroded beam under the same stress level. Corrosion has a significant effect on the fatigue life of the test beam. With the increase of the number of fatigue cycles, the fatigue damage, the gradual deterioration of the bending stiffness and the accumulation of residual strain of concrete in the corroded beam reinforce the internal structure of the corroded beam. The evolution of the fracture basically accords with the development of the “three stages” of rapid growth, steady development and rapid change. According to the test results, the fatigue life equation of S-N is established, and the calculation method of fatigue life of corroded RC beams is proposed. The results provide the theoretical basis for the assessment of fatigue properties of bridge structures.
