Research On Actual Effect And Finite Element Simulation Of RC Beams Strengthened By Three Methods Of Shear Reinforcement

With the development of 40 years of reform and opening up,most of the buildings built in the early stages have entered the mid to late stage of their lives.Due to factors such as structural aging and changes in building functions,some buildings may not be able to meet the corresponding bearing capacity requirements,and therefore require reinforcement and maintenance.Commonly used reinforcement forms include increased section reinforcement,bonded steel reinforcement,bonded fiber reinforcement and reinforced steel cladding,all with their own advantages and disadvantages.The reinforcement of beams is mainly of two types,ie,the reinforcement of the normal section and the reinforcement of the oblique sections.As the shear failure of beams is brittle,the shear reinforcement of beams requires special attention.The lack of shear resistance of the oblique section of the beam may be the corrosion of the steel bar or the change of the load,resulting in insufficient shearing due to a small stirrup ratio.It may also be due to the reduction of the strength of the concrete due to structural aging,etc.,resulting in insufficient shear resistance of the beam.In this paper,we will consider the shear reinforcement of the beam under the condition of insufficient shear resistance of the beam.Based on 13 test beams,the section size is 200mm×400mm and the beam length is 3150 mm.,in which t 9 T-shaped beams have a flange length of 600 mm.Three types of reinforcement methods,ie,adhesive steel plate reinforcement,paste fiber reinforcement and adhesive angle steel reinforcement,were used to carry out shear reinforcement tests,and the practical effects of the three types of reinforcement methods and the effectiveness of the end anchorage were explored.The test results show that in all reinforced beams,the best effect is to paste steel hoop,and the beam eventually undergoes bending damage.However,this method is difficult to achieve in practical projects.In the fiber reinforced shearstrengthened beams,the effect of anchoring the end of the U-hoop of the fiber using a steel plate or angle steel as a bead is relatively close,and the anchoring effect of the steel plate as a bead is slightly better.In the shear steel reinforcement beam of the bonded steel plate,the Ushaped steel plate reinforced by angle steel anchoring is better.In the increase of cross-section shear reinforcement beam,the increase of cross-section using stirrups threaded through the flange of the bolt to strengthen the reinforcement effect of shear reinforcement is better.In the side shear reinforcement beams,the ultimate bearing capacity of the two reinforcement methods,ie,the gluing of the fiber side and the side of the steel plate,are comparable,but the shear reinforcement effect of the steel plate-side anchor reinforcement beams is slightly better.Through the three shear reinforcement models common to three shear reinforcement methods,the model predictions are compared with the test results,and the accuracy of each model is compared.Finally,through regression fitting,three shear reinforcement models based on this experiment are proposed and are in good agreement with the experimental values.Finally,the nonlinear finite element analysis software,ABAQUS,is applied to nonlinear simulation of RC beams under monotonous displacement loading.The stress state,load displacement curve and the ultimate bearing capacity of the beams are obtained through software analysis,and compared with the experimental values.There are some errors between the simulated results and the experimental results.The main reason is that the finite model is based on an ideal state of calculation,and some improvements are needed.