Crack Analysis And Application In Concrete Beams With Simply Supported

As a kind of composite material, concrete has not continuity. Crack is one of themost common defects in the concrete engineering, so cracking is born with a nature forconcrete. And most damage collapsed projects of the reinforced concrete structure arebegan from crack propagation, a great deal of the tiny cracks exercise a little influenceon capacity、function and the durability of project structure. But when the crack changesto wider and deeper, the durability and applicability of structures will be reduced atdifferent levels, seriously it can even lead to the destruction of the structure. Therefore,This thesis includes:1. Cause, assessment, damage and mending measures of concrete cracks wereobtained based on previous work, for example, a lot of literatures;2. The paper work mainly expounds the application of the fracture mechanics inthe crack analysis of structural concrete and its numerical method;3. It describes common fracture models and its characteristics in the crack analysisof structural concrete. And the key of the paper work is simulation and analysis fordifferent fracture problem, etc. Crack equations can be obtained, and strain anddisplacement can be received by solve those crack equations. It provides a theoreticaldirection for finding load history and equilibrium state of crack;4. The finite element program was made based on Fortran language, and was usedto simulate and analysis the damage process of concrete beam with initial notches underthe constant load condition. Mode I and mixed-mode crack propagation was studiedusing this program. Load-displacement relations and crack propagation mode wasobtained, and the analytical results are in good agreement with the experimental results.