The Research Of The Influence Parameters Of External U-shaped CFRP Hoop Position On The Effect Of Shear Reinforcement On RC Beams

Fiber Reinforced Composites(FRP)are characterized by light,high strength and corrosion resistance,and are widely used in civil engineering applications.For a long time,FRP material is mainly used for structural reinforcement and repair,the U-shaped paste of CFRP is the most commonly used reinforcement method for FRP shear reinforcement reinforced concrete beams.In this paper,we first review the current application and research status of fiber composites,and then propose a new idea: to change the relative position of CFRP and stirrups and the number of CFRP layers,and then study the increasing capacity and trend of the bearing capacity after reinforcement.The specific research process and results are as follows:(1)Based on the theoretical shear failure of concrete oblique section,the concrete beams with no reinforcement of CFRP are 100 mm,150mm,200 mm,250mm and 300 mm respectively by ANSYS numerical simulation.The experimental results show that the failure mode is the same as that of the oblique section shear failure in the theory.The variation of the stress distribution between the simulated and theoretical values is also within the acceptable range,that is,ANSYS simulation is feasible;(2)The relative positions of CFRP and stirrups in the five strengthened beams were changed,respectively,and moved from the overlapping position of the stirrup and the center of the CFRP in the order of 25 mm,until the center of the CFRP was moved to the middle of the two stirrups,The results show that the bearing capacity of the beam is increasing with the increase of the relative position,but the increase rate is decreasing CFRP in the middle of the two stirrups when the reinforcement effect is the best;(3)Changing the number of layers of CFRP in the five strengthened beams shows that increasing the number of layers will increase the bearing capacity but the increase of bearing capacity is gradually decreasing;(4)Compared with the CFRP center and the stirrup position of the reinforced beams after the five beams are moved,the percentage of the reinforced beams is increased,get the beam with a large spacing of stirrups,cross-paste in the better effect of CFRP;(5)Compared with the five groups,the effect of changing the number of CFRP layers on the beams with larger stirrups is more obvious.