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The insufficiencies and defects in design, construction as well as operation management have caused a lot of diseases in prestressed concrete continuous box-girder bridge in the past 30 years, especially in the 1990s, which hampers the further application and popularization of this type of bridge in highway construction.Therefore, in order to provide useful suggestions for design and construction, and to avoid the similar questions, it is very essential to make further research on the diseases of prestressed concrete continue box-girder bridge. Taking this into consideration, following research work has been done with Shenzhen En-Shang Bridge as the project background in this paper:Firstly, based on many references, the cause of diseases was studied and diseases types, distributing pattern and shape feature have been summarized in this paper, which could be a technical support for the design, construction and maintenance of bridges of this type.Secondly, Models of spatial finite element method and plane finite element method have been established to analysis En-Shang Bridge in this paper, respectively. And the comparison of analysis results shows that, as for the longitudinal stresses, the results of plane finite element method are unsafe compared to the spatial finite element. However, the results of plane finite element model are accurate enough for project request on the whole bridge computation in bridge design;As for the transverse stresses, the results of the plan frame model with elastic constraints are safer than the finite element model, and the results of the plan frame model with elastic constraints is a properly simplified method for the computation of transverse stresses in the top of box girder.Thirdly, based on the theoretical calculation, the stress of the bridge has been tested during the construction of En-Shang Bridge, and according to the result of the tests, the test mothed of stress and test data-processing mothed are strudied in this paper.The study shows that the GL2000 creep model has better performance in the calculation of creep coefficient for the bridge built by segmental construction method, compared to the JTG62 creep model and B3 creep model.Fourthly, in the present, there is no regulation on the temperature gradient in the box-girder bridge caused by paving of high temperature bituminous concrete. Therefore, based on the test result of actual bridge, the parameters whichinfluence temperature gradient caused by paving of bituminous concrete are analyzedby ANSYS model in this paper.And according to the results of parameter analysis,some measures which can be used to prevent the excess tensile stress caused bypaving of bituminous concrete are proposed in this paper, and based on that, atemperature gradient model is also proposed in this paper, which can be a referencefor the stress calculation caused by paving of bituminous concrete in the box section.Lastly, based on the anlysis of the causes of crack and the parameter whichinfluence the stress on the bottom of the box girder at mid-span, some measures forpreventing such cracks are proposed in this paper, which could be a reference forlater bridge design and construction.
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