Research On Performance Of Reinforced Concrete Beams And Slabs Strengthened By FRP Grid

With the increasing demand for strengthening of existing structures in the field of civil engineering,and the excellent material characteristics of FRP,such as light weight,high strength,corrosion resistance and significant reinforcement effect.FRP has been widely used in the field of strengthening civil and industrial buildings,so in recent years,the research on different types and forms of FRP to strengthen concrete structures has become more and more extensive.FRP grid is a kind of two-way fiber material.Its transverse reinforcement and longitudinal reinforcement have the same physical characteristics.FRP grid also has the high strength,good durability and other excellent characteristics of FRP.Compared with FRP sheet,it has better debonding resistance and fire resistance.Moreover,the interaction between transverse reinforcement and longitudinal reinforcement of grid can better inhibit the expanding of cracks.Therefore,in this paper,FRP grid reinforcement of reinforced concrete beams and slabs are studied as follows:(1)Research on flexural behavior of reinforced concrete one-way slab strengthened by FRP grid and calculation its flexural capacity.In this paper,eight RC one-way slabs are tested in bending by FRP grid reinforcement and FRP grid-FRP anchors.The bending behavior and failure mode of the strengthened slabs are studied.The results show that the flexural capacity of reinforced concrete one-way slab strengthened by FRP grid is increased by 7%-21%,and FRP grid can effectively slow down the crack expanding and improve the flexural behavior of the slab.Based on the plane-section assumption,the equilibrium equation is established,and the calculation formula of flexural capacity of FRP grid strengthened slab under different failure modes is derived.The theoretical calculation value matches well with the test value.(2)Research on shear behavior of reinforced concrete beams strengthened by FRP grid.Based on the test of ten beams,the effects of the number of FRP grids layers,strengthening types and bonding angle on the shear resistance of RC beams were investigated.The results show that the ultimate bearing capacity of RC beams strengthened by FRP grid shear can be increased by 12% at most.It is preference that both debonding and rupture failure occur because the high strength of FRP can be exhausted.(3)Calculation formula of shear capacity of reinforced concrete beams strengthened by FRP grid.According to the shear test results of FRP grid strengthened beams and the summary of the shear capacity of existing FRP sheet reinforced concrete structures.and the failure mode and reinforcement mechanism of FRP grid are analyzed.The calculation formula of shear capacity of reinforced concrete beams strengthened by FRP grid is proposed,which provides theoretical basis for further research.