Shear Capacity Behavior Of Reinforced Concrete(RC) Beams Retrofitting By CFRP Strips

The present research study describes the shear strength of reinforced concrete(RC)beams with and without shear stirrups and strengthened with carbon fiber reinforced polymers(CFRP)externally bonded since RC beams have a higher shear strength than the flexural strength.We know that the flexural failure of the beam is ductile,which gives warning against failure,and the shear failure of the beam is a brittle failure which does not give warning,but failure occurs suddenly,which is why keep higher the shear strength than the flexural strength.The study purports of a new design model to calculate the shear strength capacity increment of RC beams by strengthened CFRP strips and also determine the different failure modes of CFRP strips intervention in shear strength,like shear with CFRP rapture,bending,CFRP strips debonding.For retrofitting/strengthening of the beam by CFRP different techniques were used,such as sideband,U-jacketing,and full wrapping.A Ujacketing method was used in this research,U-jacketing of CFRP strips by angle 45 ° and 90 °.The ABAQUS software was used to construct a model of the finite elements for beam simulation.The constructed concrete was a plastic damage model using and the other two models,the cohesive model and a perfect bond model were measured for the interface of concrete and CFRP.Six beams were generated in ABAQUS software,two were regulated and the remaining four were reinforced by varying CFRP strips.Six beams were modeled by ABAQUS software,these beams were divided into two groups,called WGroup,containing the three beams W1,W2,W3 without shear stirrups,and S-Group,containing the three beams with stirrups S2,S2,S3.The load-deflection relationship was obtained from the ABAQUS study before the failure,failure modes and crack patterns were compared and the result was compared.The finite element model results showed that the beam increases the shear strength capacity of CFRP strengthened by a 45° angle compared to the beam strengthened by a 90° angle.The results of the finite element model showed that the reinforced concrete(RC)beams without stirrups with CFRP strips had a higher shear resistance capacity compared to the reinforced beam with the CFRP strips.The maximum load increase of the strengthened RC beams with CFRP strips compared to the control beams.Usually,the results show the behavior of the RC beams strengthened with CFRP strips.The numerical method can be used to investigate extremely.It was also detected that the method could constrain parameters such as strain and damaged energy distribution in CFRP,which are not easy to constrain analytically or experimentally.