The Ultimate Bearing Capacity Of Reinforced Concrete Structural Analysis Nonlinear Finite Element Method

With the development of communication, a great deal of new-build bridges need to be evaluated, at the same time, a great deal of service bridges need to be load exalted or maintained and reinforcement, which makes it important to evaluate the service bridges' bearing capacity. At present, kinds of methods of finite-element analyzing bridge structure's limit bearing capacity for concrete's complex stress nature get the concrete's constitutive equations and destructive criterion by fitting regression line. Kinds of finite-element models have more or less deficiency for the material's complex character, which leads to the bigger deviation of the calculated numeric value, so it is limited in the range. Besides, the current bridge and culvert design criterion takes some basic postulation during the calculation of the bridge's member in bending, which results in over-conservative numeric value.Based on the nonlinear analysis researches of concrete structure at home and abroad, material nonlinear analysis of reinforced concrete beams were done by model in this thesis. An increment-tangent stiffness iteration method program was done by using the above theory and the C++Builder 6.0.The process from loading to failure was simulated, and the load-deflection curve, moment-curvature curve, and strains of element sections at different locations were got in loading stages. The results analysis was done. The computed results were exported to "txt"files. Graph post process was done, and figures showed the changes of stresses and strains on beam section visually.The computed results coincided with the experimental data, so the feasibility of the method in this thesis was proved. The results can be used as reference by researchers and structural designers and had practical value to some value extent.