Model Test And Bearing Capacity Study Of Curved Prestressed Concrete Box Girder Bridge

In the dissertation, it was reviewed that the analysis theoretical researches, model tests and bearing capacity study of curved prestressed concrete box girder, and the achievements and insufficiencies of the research of curved prestressed concrete box girder described in detail. The main purpose in the dissertation was to detailed study on ultimate bearing capacity of curved prestressed concrete box girder through test investigation and finite element analysis.The material non-linearity analytic theory of reinforced concrete structures was summarized. The constitutive equations and failure criteria of concrete were described. The combination method between concrete and rebar and the treatment method of the cracks in finite element model were also introduced in the paper. Several commonly nonlinear equations calculate methods and the convergence criterions of nonlinear equation were discussed.On the basis of that, the test model of two-span curved prestressed concrete box girder was made to research the ultimate bearing capacity of two-span curved prestressed concrete box girder to supplement current research. According to the results of the large scale model test, the nonlinearity characteristics and deformation rule of the model under symmetric vertical loads were found. As for the curved prestressed concrete box girder bridge, critical sections, distribution and development of concrete cracks and failure mode of the whole structure were concluded.Considering the particular characteristics of curved prestressed concrete box girder bridge, the ADINA program may simulate the fully process analysis of curved prestressed concrete box girder bridge under load. According to the truly size of the actually test model, the finite element model was established by considering the effect of the tendons and steel bars. Material properties of the finite element model were got by the materials test. The boundary conditions and load of the finite element model were consistent with the model test. The results of the finite element analysis showed that the whole process which included concrete cracks'appearance, development and the collapse of the structure, could be clearly described. The deformation, strain and failure mode got from this finite element analysis agreed well with which got from test, which shows that the results of the finite element analysis are full, accurate and dependable.Several conclusions which focus on the mechanical characteristics of curved prestressed concrete box girder were made in the paper according to the results of the test study and the finite element analysis. The conclusions showed that the redistribution process of inner forces and the deformation, which provided detailed test data as well as design and application reference for the structure of this type.