Experimental Research On Fatigue Behaviors Of RC Beam Strengthened With Advanced Glass-Fiber Composites

For improving the loading capability and prolonging the service life, parts of the built bridges need reinforcing. This paper tries to simulate the actual fatigue performance of reinforced bridge. By 7 experiment beams, the research is carried on about the flexural behavior of RC beams reinforced with advanced glass-fiber composites under cyclic loading. The main research contents and conclusions are as follows:1. By the result of the experiments, it is shown that: The fatigue life of RC beam which is strengthened with advanced glass-fiber composites increases by more than two times, its deflection reduces about 61% to 65% and the fatigue performance of anti-crack has more and greatly improvement. Thus, it has the advantage of improving the fatigue performance of RC beam that is strengthened with advanced glass-fiber composites and prolonging the service life of RC beam.2. Fatigue curve was fitted by the relationship between stress amplitude of steel bar and fatigue life of RC beams strengthened with advanced glass-fiber composites, and the fatigue limit value of the strengthened RC beam is deduced by the curve. In addition, by the relationship between the max crack length of strengthened RC beam and the loading cycles, and the relationship between the max crack width of strengthened RC beam and the loading cycles, the mathematical models are founded. By this, it can be studied further more about the effect of the repeated loading level and loading cycles to the strengthened RC beam.3. According to the statistics result from experiments, the strains of concrete, steel bar and fiber of the strengthened RC beams at the mid-span almost remain linear under fatigue loading. In the meantime, the method for gaining the fatigue strength of concrete, steel bar and advanced glass-fiber composites is drawn from the conclusions of the experiments. At the end, by the method of equivalent inertial moment, a checking method is brought up about the fatigue strength of the cross-section of RC beam strengthened with advanced glass-fiber composites.