Research And Analysis On Shear Performance Of Reinforced Concrete Beams Strengthened By B-FRCM Mechanism

Since the end of the twentieth century,China’s construction industry has developed rapidly,due to the insufficient construction standards of early buildings,or the reasons for uneven construction standards,over time,some buildings are about to exceed the period of use,and the building structure has begun to undergo various serious damage,and it is urgent to strengthen the structure.Therefore,the development of China’s construction industry has begun a new period from large-scale construction to "building and nourishing at the same time".For this reason,fiber reinforced polymer materials(FRP)have a series of characteristics such as light weight,high strength and oxidation resistance,and have been widely used in China’s building reinforcement and maintenance industry.The external FRP material mainly relies on the epoxy resin and other structural bonding colloids,and the FRP is pasted on the surface of the component to form a whole with the structure to resist the external load,but the epoxy resin material has defects such as poor temperature resistance,easy aging,and irritating gas when heated.In view of this series of defects,the fiber fabric mesh reinforcement system FRCM(Fabric-reinforced Cementitious Matrix system)as a new reinforcement technology began to be widely studied by scholars at home and abroad,using the FRCM system composed of new FRP grid reinforcement materials and engineering composite cementitious materials,which can effectively avoid the defects of traditional FRP materials.In view of this,considering economic,environmental protection and other factors,the B-FRCM mechanism composed of cost-effective basalt fiber(BFRP)grid and engineering cement-based composite ECC was selected to shear reinforcement the reinforced concrete beam.Combined with the research content of this project,a new technical means of BFRP grid and FRCM composite reinforcement is proposed to replace the traditional reinforcement method.At the same time,it also provides ideas for the promotion and application of B-FRCM reinforcement technology.The main research contents are as follows:(1)Taking BFRP grid parameters and stirrup spacing of reinforced concrete beams as influencing factors,5 simple support beams were designed for shear bending test,2 contrast beams and 3 B-FRCM mechanism reinforced beams,and the reinforced concrete beams were loaded by non-equal three-point static loading mechanism to explore the force failure mechanism of reinforced concrete beams from load to failure stage.(2)In the basic mechanics test,the finite element software ABAQUS/CAE 2020 was used to model and analyze the reinforced concrete beam,and the load displacement curve,steel stress and BFRP grid stress of the test beam were analyzed by post-processing,and the results obtained by comparing the results obtained were compared to verify the accuracy of the finite element modeling.(3)Referring to the Chinese norms and the research of relevant scholars on the anti-shear formula,the calculation formula of reinforced concrete beams reinforced with FRP grid composite materials was collected.Based on the research in this paper,the existing calculation formula is revised based on the truss-arch model and FRP effective strain model,and the calculation formula of RC beam with shear reinforcement of B-FRCM mechanism is obtained.Through comparative calculation,the calculated value is very close to the experimental value,which provides an effective reference for the shear reinforcement design of B-FRCM mechanism.