Research On Behavior Of Flexural Member Based On Concrete Mechanics

Flexural member is the popular component of the civil engineering, normal section bearing capacity calculation of the flexural member is the important part of the section design. The normal section flexural capacity calculation of the Code for Design of Concrete Structure is based on the experiments, although the calculation formulas have its reasonable and applicability, and the calculation results have good precision through the full considerations. But the formula is absence of the clear mechanical concept and is difficult to understand.Based on the normal section calculation assumption, the normal section's physical condition and geometric condition and equilibrium condition of under-reinforced beam are established. According to the different behavior of the flexural beam's loading phases, the height of the concrete pressured region and the flexural moment-curvature equation and the flexural stiffness are deduced on the simultaneous three conditions. On the collapse behavior of the over-reinforced beam and the rare-reinforced beam, the two kinds of beam's mechanical analysis formula of different phase are deduced like the under-reinforced beam.Based on the changing of reinforcement ratio and concrete strength, the effect to the mechanical behavior of the beam is studied with mechanical formulas. With ANSYS finite element program, the concrete beam finite element models are established on the basis of the experiment parameters. With analytical result the graphics such as moment-deflection graphic are plotted, and the graphics are compared with the mechanics analytical result. Five problems have been mainly solved in the paper as the following:1. Based on the assumptions, the calculation formulas of the single reinforcement rectangular concrete beam are established according to the physical condition and geometric condition and equilibrium condition.2. The calculation formulas are established with concrete mechanical analysis. With the analytical result, different curve graph of three kinds of beams are plotted and compared.3. Considering the changing of the reinforcement ratio and concrete strength, the effect to the concrete beam's mechanical behavior is analyzed.4. The finite element models of two concrete beams are established with ANSYS finite element program. With the analytical result, the moment-deflection graphics and stress of steel bars-moment graphics are plotted and compared with the mechanical result.5. Combining the content of the concrete mechanics and the calculation method of the Code and the requirements of the Code, the network curriculum text of flexural moment normal section's analysis and calculation is compiled.At last, some problems about this research worth to be studied further are put up.