Analysis On Flexural Performance Of Reactive Powder Concrete Unbonded Prestressed Composite Beams And Bearing Capacity Calculation

Reactive powder concrete (RPC) is a new type of cement-basedcomposite material, its mechanical properties is far superior to normalconcrete (NC) and high performance concrete (HPC), RPC will be widelyused in engineering practice. The researches on RPC are focusing onmaterial test at the present stage but relatively few researches for structuraldesign theory. Will the RPC used in prestressed composite structure, itsmechanical properties has been fully play. The flexural behavior ofReactive Powder Concrete Unbonded Prestressed Composite Beams wasanalyzed in the thesis and the prime works are fellows:Firstly, the thesis introduced basic concepts and feature of reactivepowder concrete unbonded prestressed composite beams, and summarizedformer research production for RPC and composite structure.Secondly, the three-dimensional models of reactive powder concreteunbonded prestressed composite beams were established by the finiteelement analysis software ANSYS and the tests were simulated. Comparedthe FEM results with the experimental results and the comparison showed agood performance of the proposed models. The mechanical performance anddamage mechanism of reactive powder concrete unbonded prestressedcomposite beams were analyzed by using the models.Thirdly, the main parameters that affecting the bending performance ofreactive powder concrete unbonded prestressed composite beams, such asthe effective prestress, the concrete strength grade of post-cast layer and thereinforcement ratio of post-cast layer, were analyzed. Then, the tendency offlexural capacity and steel strands ultimate stress increment that changewith the parameters were obtained and reference values for design weregiven.In addition, orthogonal analysis to RPC prestressed composite beamswere did. Influence degrees of flexural capacity and the most suitable factorcombination to enhancing flexural capacity and steel strands ultimate stressincrement were obtained.Finally, referred to the computing method for normal concrete structure and existing test results, the computational formulas for crackingmoment, steel strands ultimate stress increment and flexural capacity ofcomposite beams were deduced. A good agreement is found between theresults predicted by the computational formulas and FEM solution.