PPR Impact On The External Pre-stressing Simple Supported Beam Fatigue Life Research

Prestressed concrete structure is designed based on certain bearing capacity, andoverload causes few structural damage during the usage period. But under the repeatedload which lowers than the design value, it may arise to sudden brittle failure which calledstructure fatigue failure. Fatigue failure is one of the main reasons for the failure ofengineering accident. In addition, with the development and application of high strengthmaterials, and make full use of material strength theory, cause the structure of manycomponents to be in high stress state. Therefore, the research of prestressed concretestructure fatigue is increasingly referred to as key problems which can not be neglected. Inthe thesis, the External Pre-stressing Simple Supported beam is the main study objects,and use finite element method to analysis the prestressing force on its fatigue life. Thespecific contents mainly include the following three aspects:First of all, In the external prestressed structural design, partial prestressing ratio isone of the important indicator which need to be considered, it is also a parameters tomeasure the structure prestressed level, can affect the extent of structural deformation andfatigue performance under load, so this article analyze the PPR impact on the fatigue lifeof the external pre-stressing simple supported beam structure.Secondly, Use finite element analysis software ANSYS to analysis the externalprestressing simple supported beam in the form of fold line tendon layouts, Analysis of thedeflection of the structure under different partial prestressing ratio values.Finally, Combine with the fatigue performance parameters of materials to analysisthe fatigue life of the structural based on the results of finite element, the point that thelower edge of the main beam contact the turning block, as well as the point that theprestressing tendon contact the turning block,are most likely to occur fatigue damage dueto the stress concentration, but also the fatigue life of ordinary reinforced and prestressedreinforced at the midspan section under the different partial prestressing ratio. In addition,although the numerical analysis can be a very good understanding of the structure of theloading process, it also needs to combine with the actual engineering practice, and adoptmore numerical simulation methods to make sure its validity and reliability.