Study On Shear Behavior Of RC Beam Reinforced With Composite Polymer Mortar Of Wedge Steel Plate Jacket And Steel Wire Mesh

In recent years,with the rapid development of China’s construction industry,Many old reinforced concrete structures have been unable to meet the requirements of the existing codes.The existing reinforcement technology mainly has the following shortcomings:(1)The construction process is complex;(2)The cost is relatively high;(3)When strengthening,the original structure should be grooved,punched and injected with structural adhesive,which will damage the integrity of the original structure and cause some pollution to the environment.In this regard,a new combination reinforcement method was proposed by the research group: Wedge steel jacket and Steel wire mesh composite Polymer mortar reinforcement technology.Strengthened beams are shown to be convenient construction,less material consumption,less environmental pollution and other advantages.The test results show that the strengthened beam has larger rigidity,stronger resistance to deformation,higher load and better ductility when it is damaged.In this paper,nine reinforced concrete beams are analyzed by shear tests: three contrast beams and six strengthened beams.The effects of prestress and shear span ratio on the shear performance of RC beams are analyzed and explored.The main work of the experiment is as follows:(1)Nine RC beams were subjected to shear tests,the effects of shear span ratio and prestress level on shear performance of strengthened beams are studied.(2)By analyzing the load deflection curve of beam,the load strain curve of stirrup and steel strand.To explore the improvement of shear performance of test beam under two factors of prestress and shear span ratio.The test results show that the bearing capacity and ductility of the strengthened beams are obviously improved.(3)Through the analysis of the test results and the crack development of the beam failure.It shows that the development of cracks can be effectively restrained by reinforcement technology;When the specimen is sheared,there is no sudden failure.(4)In the process of beam failure,the width of inclined crack and other data are collected,The influence of prestress level on crack width is analyzed.The results show that the cracks can be effectively restrained by prestress.Under the same load level,the crack width of beams with higher prestress is smaller.(5)Based on the limit equilibrium theory,the calculation formula of shear strength of RC beams strengthened by composite polymer mortar of wedge-shaped steel plate stirrups and steel wire mesh is derived.Meanwhile,the reference formula suitable for strengthening beams in practical engineering is put forward.