Experimental Study On Shear Behavior Of Damaged Beams Strengthened By Prestressed Wire

In this paper,the author conducted a study of engineering test on the strengthening effect on damaged beam strengthened by prestressed wire.The results suggest that both shear capacity and stiffness are improved through the damaged beam strengthened by prestressed wire,which proves the applicability of the strengthening technology of prestressed wire in practical engineering.In this paper,five group's of tests are designed and carried out for experimental study on strengthening effect of wire winding on damaged concrete beams.The first one is the undamaged unstrengthened RC beam.The second is the undamaged strengthened RC beam,and the other three are damaged strengthened RC beams.The crack width was selected as the damage index and the crack width were 0.2mm,0.4mm and 0.6mm respectively.The influence of damage degree on shear capacity and deformation capacity are studied by analyzing the failure form,load-deflection curve,stirrup strain and other test results.The results show that the shear capacity of the undamaged test beams strengthened by wire winding is higher than that of the unstrengthened beams.Through the comparison between the damaged specimens,it is found that when the prestressing of the steel wire is the same,the shear capacity of the strengthened beam decreases with the increase of the damage.From the test results,it can be seen that the strengthening effect of prestressed wire can effectively inhibit the development of oblique cracks in RC beams,improve the failure mode of strengthened beams and significantly improve the ductility and bearing capacity of beams,In this paper,the finite element analysis software is used to simulate the test beam.By comparing the stress relationship,bearing capacity and deflection between the actual test and the simulated test,the correctness of the finite element test model is verified.On the basis of verifying the correctness of finite element software simulation,the influence of different prestress and shear span ratio on the shear behavior and strengthening effect of damaged beams is also simulated.The results prove that different prestressed wire have certain influence on the strengthening effect of damaged beams,and the bearing capacity does not increase strictly with the increase of prestress.When the damage of the beam is within a certain range,the bearing capacity of the damaged beam is positively correlated with the prestressing stress.If the damage of the beam is too serious,the ultimate bearing capacity of the strengthened beam will decrease instead of increasing.It is found that the shear capacity of the test beam is inversely proportional to the shear span ratio by simulating different shear span ratios.In this paper,the design formula of shear capacity of damaged beams strengthened by prestressed wire is discussed and the calculation formula of shear capacity of damaged beams strengthened by prestressed wire is derived.By comparing the calculation results,test results and simulation results,it can be concluded that the derived calculation formula for the bearing capacity is in good agreement with the test results,which proves that the derived formula is applicable in practical strengthening works.