Research On Causation Of Defects And Security Evaluation Of Long-span Prestressed Concrete Continuous Girder Bridge

With the further development of the bridge construction and the promulgation and implementation of the new norms , the safety, durability requirements of the existing bridge are also getting higher and higher to communications and transportation. Therefore, to a part of disease or even hide the hidden dangers of the bridge, its security status to make effective assessment may have great significance. According to the theory of the security assessment of the bridge structure, this paper analyzes and researches the diseases security status assessment methods of the bridge based on a continuous bridge, the following main elements:1. This paper detailed overviews the diagnosis methods of the bridge structure disease and comprehensive analyzes their advantages and disadvantages; comprehensive summarize the basic contents and methods of the security assessment for the concrete bridge. This paper elaborates on the identification methods of the carrying capacity of the bridge and analyses nondestructive testing methods used in the analysis of reinforced concrete strength and corrosion detection and analyses the testing methods of the structural components of the test material defect.2. This paper testing and arranging the main diseases of the bridge and analyzing and studying the main reason for their based on the wagon bridge, and this paper detected the bridge to evaluate its rigidity, intensity and bearing capacity with evaluation theory of loading test.3. According to the bridge's original design drawings, this paper did emulator calculation to the construction process of the bridge and analyzed the stress of the structure during construction stage and service stage with MADIS civil engineering, furthermore, this paper analyzed the influence of the disease may exist in the bridge with full-bridge model. this paper also did sensitivity analysis to the major affecting parameters, such as pavement deviation, angle of the under floor, longitudinal pre-stressed losses, gravity of the main beam, dignity of the structure and analyzed the effects to the main beam deflection and stress caused by these disease on the bridge structure in the construction stage and the service stage, at last, this paper Summed up the law and got conclusion which may have guiding significance to the design and construction of similar bridges.4. This paper carried checking calculation to radial force caused by pre-stressed bar in mid-span closure segment and carried local calculation to mid-span closure segment when it under vehicular load for get the reason of the cracks in there.5.This paper present the cracks repair method and the bridge health monitoring recommendations against cracks disease.