| Currently, most of the analyses on the structural simulation for entire bridge are based on the theory of 2D or 3D beam Finite Element Method (FEM), whereas solid element method is seldom to be based on due to its immaturity. It is feasible to use beam FEM combined with partial solid FEM for RC bridges or simple PC bridges simulation, but when it comes to the special shape bridge and milt-directional curved prestressed bridge, such theories cannot fully meet the needs of designers. With the rapid increase in large span and complicate bridge forms, as well as the development in computer technology and FEM theory, the Structural 3D Simulation for Entire Bridge (SSEB) has stepped onto its substantial stage of research and development. By means of SSEB, boundary condition and load situation can be real reflected, and more accurate and reliable analysis results can be obtained to assist design and construction.Based on FEM software ANSYS and MATLAB, the simulation analysis approach for 3D entity model of PC bridge structures and relevant key theories as well as program developing strategies were studied in this paper. The research is focused on the line shape prestressing tendon simulation, equal translation of prestressed effect and cross-section slice technology. The research results, which can be widely applied in 3D simulation of PC bridges, will have its theoretical and practical significance.Theoretical and numerical researches in this paper are carried out in the following aspects, with some achievements accomplished:1. Considering the characteristics of prestressing tendon layout in bridge design and construction, non-uniform B-Spline in CAGD was successfully introduced into simulating 3D curved prestressing tendon, and it became the theoretical premise of this research as such.2. A numerical formula to calculate the prestressed losses due to friction and the pipeline local defection of 3D curved prestressed tendons was deduced. Also, with consideration to unfriction, another formula to calculate the anchorage losses was deduced in this paper.3. According to prestress equipollent load theory, prestressed effect was realized. That means the concentrated force on the fixed end of anchorage and the internal prestressing radial force could be transformed equivalently on entity elements. This method can be applied in various solid elements.4. In view to the diversity of bridge sections, a restraint Delaunay triangle net division method was brought up. Theory of section geometrical feature, section endogen force and right section bending resistance capacity calculation were studied to solid modal.5. The visualization technique of cross-section slice and matching auxiliary techniques for entity model were put forward and realized by programming, and provides a method for accurate analysis and analysis with high-capacity results data.6. Based on the message-handling mechanism of Windows, the command line of ANSYS was successfully intercepted. By applying FORTRAN language and C++ object-oriented programming, a professional analysis modular with PC structure handling ability based on ANSYS and MATLAB was explored. Therefore, the static analysis for PC box girder on entity model could be carried out.Only a few codes were compiled for accomplishing the above achievements, but powerful capabilities of ANSYS such as pre/post processors, solvers, and MATLAB C++ mathematical function library could be used fully. Since the task was built upon the ANSYS and MATLAB platform, it means the attempt of software development in this paper was rather effective.The paper has profound theoretical and practical significance in improving the design level and efficiency of PC bridges, popularizing the application of finite element method (FEM), and promoting the development of professional software.
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