Experimental Study On Shear Resistance Of FRP Composite Bars/FRP Textile Stirrups Concrete Beam

The premature deterioration and destruction of the structure caused by the corrosion of steel bars has become a very serious problem in engineering.At present,there are two main methods to solve this problem,namely,the protective treatment of the steel bars and the reconstruction or reinforcement of the damaged concrete structures,however,these two methods can only alleviate the durability problem caused by steel corrosion to a certain extent,but it cannot solve this difficult problem fundamentally.In recent years,some scholars have tried to replace the longitudinal and transverse steel bars in traditional reinforced concrete members by using FRP materials which have excellent mechanical and corrosion resistance from the perspective of replacing structural materials,so as to fundamentally solve the problem of steel corrosion.Among the few published results,scholars mainly focus on the use of FRP bars or steel-FRP composite bars to replace the steel bars which proved to be feasible,and only a few scholars began to try FRP stirrups instead of steel stirrups.The study of using FRP textile stirrups to replace the steel stirrups in concrete structures has not been discovered.Therefore,this paper decided to use the skeleton formed by FRP composite bars/FRP textile stirrups to replace the traditional steel skeleton,and to study the shear performance of FRP-concrete composite beams.Nine test beams were designed and fabricated,and then a three-point loading bending test was used to prove the feasibility of using this new structural form in the shear capacity of beams.At the same time,the effect of FRP textile stirrups on the shear performance of beams was mainly studied.The research results are mainly reflected in the following four aspects:1)Comparing and analyzing the failure mode,load deflection relationship and crack mode between the ordinary reinforced concrete beams and FRP-concrete composite beams to verify the feasibility of FRP-concrete composite beams;2)By analyzing the strain distribution,stress-strain relationship and failure mode of FRP textile stirrups in the test beam,to study the effect of the arrangement,the installation method and the reinforcement form of the FRP textile stirrups on the shear performance of test beam;3)Through the calculation and analysis of the strain obtained during the test,the calculation method of the FRP textile stirrups shear contribution is proposed,and the interaction between the FRP textile stirrups and the concrete,and between the longitudinal and transverse strips of FRP textile are compared and analyzed;4)Try to establish the calculation model of the shear contribution of FRP textile stirrups,that is,based on the truss model and considering the FRP textile arrangement,the main shear crack angle to establish a simple FRP textile stirrups shear contribution calculation formula,and in the case that one direction strip of FRP textile parallel to the longitudinal length direction of beam,the shear calculation model of the FRP textile also proposed.The models provide a theoretical basis for the subsequent FRP-concrete composite beam experimental study.