Study On Mechanical Performance Of RC Slab Strengthened With FRP

Reinforced concrete two-way slab,as a common component in building structure,needs to be repaired because of its service life and force majeure.Fiber reinforced polymer(FRP)is a new reinforced material originated in 1980 s.After a long time of research,it can be seen that compared with other reinforcement methods,FRP reinforcement structure has little impact on the appearance of the building,and almost does not change the original section size of the structure.Moreover,FRP has the advantages of light weight,high strength,corrosion resistance and good tensile performance,which makes it more and more widely used in the field of structural reinforcement.At present,there are more researches on the impact shear behavior of the two-way concrete slab strengthened by CFRP sheets,but less researches on the impact shear behavior of the two-way concrete slab strengthened by CFRP sheets.In this paper,the impact shear behavior of FRP composite reinforced concrete two-way slab is tested,numerically simulated and theoretically studied,which provides theoretical basis for FRP reinforcement technology and its application in engineering.In this paper,the loading position,the amount of reinforcement and the method of reinforcement are used as the test parameters.Under the conditions of FRP composite reinforcement,the punching test of 9 concrete two-way slabs is carried out to study the limit length and failure test of the specimen under the action of middle placement and substitution The research shows that the failure of the test piece is divided into three stages: the non-cracked stage,the stiffness of the reinforced plate is at this stage and is in the elastic stage;the cracked stage,the stiffness of the reinforced plate begins to decline,and the slope of the twist-bend curve begins to deflect For the steel bars in the mid-loaded test specimens,the steel bars reached yield,and for the loaded test specimens,the steel bars reached yield;during the failure stage,the punched thin slices of the reinforced concrete slabs formed at this stage,and fell rapidly and the specimens suddenly failed.Among them,the ultimate bearing capacity of the loaded specimen is greater than the ultimate bearing capacity of the specimen during central loading;the embedded FRP reinforcement has at least one better ground suppression effect on the fracture of the test fragments;the bearing capacity of the specimen overcomes the increase of the reinforcement Non-linear increase;in the case of the same amount of reinforcement,the composite reinforcement effect of FRP bars and FRP plates is the best.The finite element simulation of the test piece was carried out through the ABAQUS software.Based on the verification of the simulation results and the test results,the effects of the FRP bonding length,the amount of reinforcement and the composite reinforcement on the mechanical performance of the concrete strengthening plate were further analyzed.The simulation results show that the ultimate bearing capacity of the reinforced plate will increase with the increase of the FRP bonding length;increase with the increase of the reinforcement amount;change with the change of the reinforcement method,and the CFRP cloth has the best reinforcement effect.The FRP bonding length in the test parameters has the most obvious effect on the ultimate bearing capacity of the test piece.When the end of the reinforcement material is located near the position of the support,the FRP has the best punching and strengthening effect.According to the existing national standards and the punching theory of concrete slabs,combined with the research results of FRP reinforced concrete two-way slabs,this paper establishes the calculation formula of the ultimate bearing capacity of FRP composite reinforced concrete two-way slabs under the action of plastic loading through the theory of plastic hinge line calculation And verify the results.The results show that the theoretical calculation values obtained by applying the formula are in good agreement with the experimental values.