Research On Flexural Behavior Of New Fabricated BFRP Profile-Concrete Composite Beam

Basalt fiber reinforced polymer(BFRP)profile is a new composite material with many advantages such as corrosion resistance,wide applicability,light weight and high strength.It is combined with prefabricated closed stirrups to form Fabricated BFRP Profile-Concrete New Composite Beam.The composite beam structure,while reducing the self-weight of the structure and improving the bearing capacity of the structure,solves the problems of easy corrosion of the steel bars in the reinforced concrete structure and slow binding of steel bars.Through experimental research and finite element analysis,the bending performance of Fabricated BFRP profile-concrete new composite beam is studied.With reference to the technical specifications of the steel-reinforced concrete composite structure,the theoretical formula for the bending capacity of the test beam is established to provide a theoretical basis for the design of Fabricated BFRP Profile-Concrete New Composite Beam.The main work of this paper is as follows:(1)In order to study the effect of different types of longitudinal tensile profiles and stirrups on the bending performance of the test beam,6 Fabricated BFRP Profile-Concrete New Composite Beams and 2 reinforced concrete reference beams were prepared.The test results show that the ultimate bearing capacity of all test beams is higher than the reference beam.Inclined stirrups can effectively suppress the development of cracks in the test beam,and at the same time,the ultimate bearing capacity of the test beam is increased by 24.2% compared with straight stirrups.After the crack of the inclined section of the test beam,the shear strength of the inclined stirrup is better than that of the straight stirrup,and the strain of the closed stirrup near the support is greater than that of the closed stirrup at the far support during the stress process,indicating that it is close to the support The stirrup at the place bears a larger value of shear force.(2)Based on the "Technical Regulations for Steel Reinforced Concrete Composite Structures" JGJ138-2001,a theoretical formula for flexural bearing capacity of fabricated BFRP profile-concrete new composite beams is proposed.The calculated results agree well with the experimental results.It provides a theoretical basis for the design of fabricated BFRP profile-concrete composite beams.(3)Based on the bending performance test of fabricated BFRP profile-concrete new composite beam,a test beam model was established and its validity was verified.A reasonable model is selected to analyze the influence of factors such as concrete strength,profile diameter,and stirrup spacing on the bending performance of the test beam.The simulation results show that the ultimate bearing capacity of the test beam increases as the strength of the concrete and the diameter of the longitudinal tensile profile increase.Concrete strength increased from C40 to C70,and the ultimate bearing capacity of both groups of beams was increased by more than 30%.With the increase of the longitudinal tensile profile pipe diameter from 20 mm to 50 mm,the bonding and pinning effect of the longitudinal tensile member and concrete increased,resulting in an increase in the ultimate load of the test beam by 55.12%.With other parameters being the same,the spacing of the reinforced stirrups increased the ultimate load of the test beam by 7.88%.