Analysis Methodology And Bonding Mechanism Of Reinforcement On Concrete Component With Curved Section By CFRP

CFRP reinforcement technology,which due to its excellent material properties and its convenientconstructing method,is widely applied in the reinforcement projects of concrete bridge.The pasted performance of CFRP and concrete has become a notable focus and adifficulty rapidly.Based on the discovery from the large amount of literature,most of the existing research outcomes appear to rely on the experiment on uniform section structure,which not only tends to be lacking in theoreticalfoundation,but also leads to experimental discreteness to a certain degree.Therefore,this thesis aims to unfold the research based on the component with curved sectionof CFRP reinforcement.The tensile shear test on 26 concrete test-pieces with different curvature would focus on researching the interface bonding failure characteristicsof the component withcurved section CFRP concrete,the force transfer mechanism,and thestress distribution law.Furthermore,further research tends to aim at the crushing test of 3 concrete arch ribs in order to study the failure mode,the crack distribution law,and the enhancing effect of ultimate loading capacity under diverse reinforcement types.In the interface bonding model test,the concrete strength grade,the pasted layer number,the pasted length,and the curvature are treated as respective parameters,which through the analysis on the enhancing effect of ultimate loading capacity of model components,the CFRP pasted layer number and the curvature show a significant influence on the ultimate loading capacity of the component,but there is merely less affect acquired from the concrete strength grade and pasted length.Simultaneously,the reinforcement performance of the component with curved section tends toincrease along with the decline of curvature,namely that the flatter the structure is the more dramatical increase of loading capacity would occur.In addition,the types of the interface failure of components with curved section mainly includes deboning along crevice toward two sides,tensile failure,and deboning along crevice toward one side,which during the actual machining process,the pasted craft must be strictly followed,and also reasonable anchoring method should be applied in order to avoid the deboning along crevice toward one side.Different methodologies of reinforcement,including reinforcing the under surface of the vault plus the upper surface of the spandrel at the same time,and merely reinforcing the under surface of the vault,are applied in the RC arch model experiment.Research shows that the integral reinforcement in comparison to the partial one performs a better loading capacity.The application of CFRP reinforcement is able to decrease vault down warping effectively,to control the extension and the unfolding of crevice,and to improve the entire rigidity of structure.The adherence strength of the component with curved section is the coefficient result of bonding shear stressand peeling normal stress.Thus,the bond-slip constitutivemodel of uniform section componentsand thepasted strength model is no longer applicative.The modification of Lu Xingzheng model would be achieved after contrasting the existing the bond-slip constitutivemodeland the bonding strength model,and this is very likely to point out the consideration of curvature affected concrete CFRP-the bond-slip constitutivemodeland bonding strength model.According to the relevant theory of Elastic mechanics and Structural mechanics,the component with curved section CFRP-concrete stressanalysis formula would beinferred.Nonlinearity finite element software Midas FEA is applied in order to simulate the integral process of the reinforcement concrete arch with CFRP.Through the comparative analysis between the finite element results(P-w curve,steel strain,CFRPstrain)and experiment outcomes,the rationality of the finite element is tested,and also this would provide a guidance or a reference for the relevant numerical analysis in the future.