Experimental Study On Shear Behavior Of CFRP Grid Reinforced Concrete Flexural Members

With the development of science and technology,more and more new materials are produced.The carbon fiber composite grid is a kind of overall grid which is made by immersing the carbon fiber in corrosion resistant resin.This material has the characteristics of low density,high tensile strength,corrosion resistance and fatigue resistance.Because of the interconnections between the two tendons in the two directions,it has good overall performance.The characteristics of easy construction enable it to have a good application prospect.Applying CFRP grid to concrete flexural members will greatly enhance the corrosion resistance of components and prolong the service life of buildings.At present,CFRP grids are widely used in reinforcement projects,and are seldom applied in new buildings.The main work of this paper is to study the shear behavior of CFRP grid reinforced concrete flexural members.In this paper,a new CFRP grid material with independent intellectual property rights in China is used to study the shear resistance of the concrete simple beam instead of the traditional steel hoop.Firstly,the experiment of CFRP grid single limb tendons and CFRP grid nodes is carried out by independent innovation design experiment components.The experiment shows that the tensile strength of CFRP mesh is high which has good application value,but the strength of the node is far less than the tensile strength of the steel bar.Then,7 CFRP grid stirrups concrete beams and 1 ordinary steel stirrup beams are designed for different shear span ratio,stirrup ratio and different ways of grid layout.In the component design,longitudinal bars are all replaced by CFRP bars.The experimental component is loaded by two points to get the development characteristics of failure process,failure mode,deformation performance and shear diagonal cracks.By comparing the different shear span ratio and the ratio of the stirrup,the influence on the ultimate shear capacity of the component is analyzed,and the advantages and disadvantages of the two different CFRP grids are compared.In the theoretical analysis,the traditional theoretical research mainly studies the ultimate bearing capacity of the component and neglects the influence of the shear strength of the longitudinal reinforcement.This paper mainly uses the modified pressure field theory,the truss arch model,the tension bar theory and the limit equilibrium theory to analyze the shear bearing capacity of the components.In this paper,an analytical method which can analyze the whole process of component shearing is developed.In the analysis of shear bearing capacity of components based on the limit equilibrium theory,the calculation method of shear bearing capacity is put forward considering the contribution of longitudinal reinforcement and longitudinal abdominal tendons to shear bearing capacity.By comparison,the theoretical analysis values of these models are in good agreement with the experimental values.In the end,the finite element analysis of flexural members of CFRP grid reinforced concrete is carried out by ABAQUS finite element software.The simulation results are in good agreement with the experimental results.On this basis,the influence of the stirrup rate and shear span ratio on the ultimate shear bearing capacity of the component is supplemented.