The Analysis And Research For The Mechanism Of Ultimate Torsion Strength Of Prestressed Concrete

This thesis presents the research status in quo and development direction of the interaction of ultimate torsion strength of prestressed concrete in China and abroad, and establishes the research content and method. Up to the present, the opinion in the mechanism of ultimate torsion strength of prestressed concrete has not been identically gained, many scholars and institutes have accordingly put forward own views with those experiments. This thesis start with capability of endure strength of prestressed concrete in pure torsion, and analyze the destroy mechanism and configuration of prestressed concrete in pure torsion with the space truss theory with variable inclination. And with the fundamental principle of generalized prestress and the character of equivalent load, put forward the method of configuring reinforced steel bars of spiral broken lines in concrete, so as to increase the ultimate torsion strength. Meanwhile, on the basis of the theory of the space truss theory with variable inclination, income the conception of pre-torsion quadrature into the calculation method of the ultimate torsion strength of prestressed concrete in pure torsion, and then, on the basis of the research of finite element theory, including destroy rules and the stress-strain relations of materials of prestressed concrete in pure torsion, build the nonlinear finite element analysis models of prestressed concrete in pure torsion, and analyze three prestressed concrete beams in pure torsion in different conditions with Finite Element Program ANSYS.Through the colorful figure and post-process of time-history analysis of three prestressed concrete beams in pure torsion, can clearly see the stress and strain status of steel bars and concrete and the process of cracks developing, illuminate the accuracy of finite element program, and the computer program can make up the lack of experiments. Then through the analysis, illuminate increasing the value of effect prestress and configuring reinforced steel bars of spiral broken lines in concrete can magnify the ultimate torsion strength, but the method of configuring reinforced steel bars of spiral broken lines in concrete, can effectively magnify the ultimate torsion strength without increasing the quantity of steel bars. This thesis ' conclusion would be help to the design and construction of the project.