Study On Shear Performance Of FRP Textile Stirrup Concrete Beams With Shear Span Ratio And Stirrup Ratio

The degradation of concrete structure performance caused by steel corrosion has become a serious problem that seriously threatens structural safety and the development of social economy.Although the technical means such as the existing structural repair and the protection of steel can achieve certain effects,it can not fundamentally solve the drawbacks of steel corrosion.From the existing literature,it is feasible to use FRP straight reinforcement instead of concrete internal reinforcement,and it has different degrees of improvement in terms of mechanics and durability.However,due to the defects in manufacturing process and stress loss of FRP stirrups,it becomes the main constraint factor for the practical application of FRP-concrete composite structures.The FRP textile has the advantages of convenient construction,low cost and almost no stress loss after forming.Therefore,this paper proposes a method of replacing the stirrups inside the concrete with FRP textile stirrup to solve the existing defects of FRP stirrup.Because the shear span/effective-depth ratio and the stirrup ratio are important factors affecting the shear resistance of concrete beams,15 concrete beams are designed and tested in three-point symmetric loading.The shear span ratio and the stirrup ratio are mainly studied for the effect of the shear performance of the FRP textile stirrup concrete beam.First of all,based on the three-point symmetric loading test,the load-deflection curve,the FRP textile stirrup shear contribution,the FRP textile stirrup strain and the maximum crack width are analyzed.The influence of shear span/depth ratio and stirrup ratio on the shear performance of FRP textile concrete beams was investigated.Secondly,the strain of the FRP textile stirrup through the critical shear crack is applied to calculate the actual shear contribution of the FRP textile stirrup,so the actual shear contribution of the concrete is further obtained.The actual shear contribution of FRP textile stirrup is compared with its experimental value.The influence of shear span ratio on the actual shear contribution of FRP textile and concrete is discussed.The cooperative working mechanism between FRP textile stirrup and concrete is discussed.A further understanding provides a theoretical basis for the initial establishment of a calculation formula of the shear contribution of FRP textile stirrup considering the influence of shear span/depth ratio.Finally,by analyzing the existing relevant shear calculation models and combining the existing experimental data,the proportion of the shear contribution of the horizontal and vertical strips of the textile stirrup and the influence of the effective strain are further analyzed.Considering the influence of the shear span/depth ratio,the calculation formula for the shear contribution of the FRP textile stirrup was initially established.