External Pre-stressing Reinforcement Concrete Simple Support Beam Bridge Fatigue Research

With the increasing of the service life of the bridges in our country and the heavier moving load applied on them, there are more and more bridges step into the maintenance and reinforcement stage. The external pre-stressing reinforcement method plays a very important role in this reinforcement problem. The highway bridges fatigue analysis of our country is in the initial stage, so we did not have much analysis on the external pre-stressing reinforcement fatigue problem. But if bridge fatigue failure happens, it would endanger people's life and economic safety. With all these above, I decide to analysis the external pre-stressing reinforcement bridge fatigue in this paper. The main works of this paper includes:1,Introduce the paper analysis background, summarize the related researches and basic theories and bring forward the research work of this paper.2,Summarize the external pre-stressing structure fatigue problems and the parameters which may affect the pre-stressing structure.3,Analysis two finite element models of external pre-stressing concrete simple support beam with different tendon layouts, which are straight line and fold line. Find out that the reinforced bar and external pre-stressing tendon would not failure in the common situation, the failures always happen in the tension area of the concrete structure.4,Analysis failure patterns of the straight line and fold line layout beams under the fatigue load and the impact of the different pre-stressing ratio on structure performance under fatigue load. Get the conclusion that the fold line layout is better than the straight line layout and a proper higher pre-stressing ratio is contribute to avoid the fatigue failure.5,Analysis the external pre-stressing structure crack increasing problem under the fatigue load, and discover that the second order effect does not have a obvious effect on the crack increasing problem. Most time of the crack increasing life is spend on the invisible micro-crack. In the meantime, discuss the effect of different crack height ratio on the crack increasing problem and get the conclusion that the cracks should be found and treated at the early stage.