Study On Nonlinear Practical Analysis Method Of Corroded Reinforced Concrete Beam

Reinforcing bar corrosion is one of the most important factors which deteriorate durabilityof concrete structure and its component. Study on the bearing capacity of corroded reinforcedconcrete component is the key of the basic theory research on durability of reinforcedconcrete structure.At the beginning of the paper, the corroded reinforced concrete beam is regarded as acomposite beam which consists of corroded steel bars and concrete, with bond-slip considered.According to the deformation compatibility relationship between corroded steel bars andconcrete, on the basis of the constitutive relationship which can reflect the mechanicalproperties of corroded steel bars and concrete respectively and the bond-slip constitutive law,a nonlinear differential equation for the beam, expressed in the form of the tensile force (N) oflengthways uniform corroded steel bars, is derived. A nonlinear analytical solutionconsidering the bond-slip of the beam is obtained by solving the differential equation, bywhich a coordination coefficient in the form of the characteristic value of the beam ((?)) isdeduced. Due to the coordination coefficient, a nonlinear practical analysis method which canexactly reflect the bearing capacity and deformation of the beam is established. Theeffectiveness and accuracy of the practical analysis method is demonstrated by comparing itsvalues calculated by FORTRAN computer program with the former validated experimentalresults.Moreover, many influence factors, such as different loading forms, different locations ofloading, anchor situation of the beam end, which can affect the coordination coefficient of thecorroded reinforced concrete beam are discussed. A theory expression which reflects therelationship of section coordination coefficient and corrosion rates of steel bars or crack widthis obtained. Comparison result of the theory expression with regressive curve of existingexperiments shows that the test method is unilateral.Furthermore, a primary discussion on the bearing capacity and deformation of thecorroded reinforced concrete beam when its steel bars are lengthways non-uniformcorrosion is performed by the nonlinear differential equation for the beam. A nonlinearpractical analysis method of non-uniform corroded beam is established. On the basis of themethod, a calculation expression which can reflect the bearing capacity and deformation ofthe beam under the loading condition of double symmetric concentrative load anduniformly-distributed load is established. Taking the double symmetric concentrative load foran example, Paralleling the result calculated by FORTRAN computer program with theformer validated experimental results proves the reliability and accuracy of the nonlinearpractical analysis method.In the end, It is studied that the nonlinear finite element model was simulated to analyzethe bearing capacity and deformation of the non-uniform corroded reinforced concrete beam by utilizing finite element software ANSYS. Because the simulated result is in agreementwith the program result, the accuracy of the nonlinear practical analysis method isdemonstrated well again.