Flexural Behavior Of GFRP Bars Reinforced Steel Fiber Reinforced Sea Sand Concrete

Compared with steel bars,FRP bars have been widely used because of their light weight,high strength and excellent corrosion resistance.Due to carbonation of concrete,corrosion of reinforcing steel,environmental impact and other factors resulting in a serious shortage of reinforced concrete structure load-bearing capacity and reduced durability.This paper proposes to replace steel reinforcement with GFRP bars and replace river sand with sea sand to solve the environmental problems caused by excessive mining of river sand in China,but due to the low modulus of elasticity of GFRP bars and the bonding performance with concrete is not as good as that of steel bars,which leads to the problems of wide cracks and large deformation in GFRP reinforced sea sand concrete beams,etc.The incorporation of steel fibers in FRP reinforced sea sand concrete beams can reduce the crack width and deflection of beams and improve the cracking load and ultimate load capacity,The research on the stress performance of GFRP reinforced steel fiber sea sand concrete beams is of great significance to solve the environmental problems and improve the suitability and safety of concrete structures.In this paper,four GFRP reinforced steel fiber sea sand concrete beams and one GFRP reinforced sea sand concrete beam were designed,and the mechanical tests of steel fiber concrete,GFRP reinforcement and four-point flexural tests of GFRP reinforced steel fiber sea sand concrete beams were studied to compare and analyze the 2 influencing factors of reinforcement rate of GFRP reinforcement and volume rate of steel fiber.The results show that(1)the compressive and tensile capacities of sea sand concrete specimens incorporated with steel fibers are improved relative to those of sea sand concrete specimens without steel fibers;(2)the GFRP reinforcement steel fiber sea sand concrete beams are basically compounded with the assumption of flat section;(3)the reinforcement rate of GFRP reinforcement has a greater influence on the ultimate load,cracking load and crack development of GFRP reinforcement steel fiber sea sand concrete,and the steel fiber volume rate has a greater effect on the cracking load and crack development of GFRP reinforced steel fiber sea sand concrete beams.ABAQUS finite element analysis was carried out on the flexural behavior of GFRP bars reinforced steel fiber reinforced sea sand concrete beams.The numerical simulation of cracking load,ultimate bearing capacity,plastic damage of concrete and tensile stress of GFRP bars was carried out with the finite element model established.The simulation results are in good agreement with the experimental results,the model has applicability.The damage patterns of positive section of GFRP reinforced steel fiber sea sand concrete beams have two modes of tensile damage and compressive damage;based on the assumption of flat section and considering the influence of steel fiber sea sand concrete in the tensile zone,the proposed formula for calculating the bearing capacity of GFRP reinforced steel fiber sea sand concrete beams is given.