Experimental Study On Shear Performance Of Loaded RC Beams Reinforced With RPC Steel Mesh

Reinforced concrete(RC)beams are commonly used horizontal stress members in concrete structures.Construction errors,external environment and load changes may cause them to fail to meet the requirements during use.When brittle shear failure occurs,it poses a serious threat to the safety of people’s lives and properties,and needs to be reinforced.In order to solve the problem of insufficient shear resistance of RC beams,a four-sided reinforcement technology combining reactive powder concrete(RPC)and steel mesh is proposed.structure.Similar to the method of increasing the section,it is necessary to deeply chisel the concrete surface and implant evenly distributed pins to ensure the synergy between the reinforcement layer and the original beam concrete.The reinforcement layer of RPC steel mesh can significantly improve the stiffness,cracking load,ultimate bearing capacity and deformation capacity of shear beams.At present,the research on RPC reinforced beams mainly focuses on the field of primary stress,that is,the members have no initial damage before reinforcement and are directly loaded to failure after reinforcement,and the influence of actual preload is not fully considered in the existing calculation methods.The reinforcement method mentioned in this paper is completed under the load state.Based on the three-point bending test,the shear mechanical properties of the reinforcement members are analyzed and studied.Combined with ABAQUS finite element software to simulate and expand parameters,the feasibility of this reinforcement technology in practical engineering applications is clarified.In this research,the author mainly discusses the following three aspects:(1)Experimental research.6 RC beams were designed and fabricated,of which 5beams were reinforced with RPC steel mesh on all sides,and 1 unreinforced beam was used as a comparative specimen.Through 3-point static load bending test,the effect of shear-span ratio and reinforcement layer hoop ratio was mainly studied.Influence of the reinforcement effect of a loaded RC beam.The results show that all the reinforced beams are shear-compression failure,and the reinforcement layer and the original beam work together during the failure process,and no interlayer slip failure occurs.Compared with the unreinforced beam,the section size of the reinforced test beam does not change much,but the shear bearing capacity and deformation capacity are significantly enhanced,and the shear bearing capacity is increased by a maximum of 2.4 times.(2)Shear calculation.The relevant formulas in the existing code are not applicable to the calculation of the shear capacity of the beam in this test.The author uses the simple superposition method and the truss-arch model to analyze the shear contribution of each part of the reinforced beam under load,and considers the stress hysteresis phenomenon of the reinforcement layer material,reduces it,and finally gives the shear resistance of the reinforced beam.Bearing capacity calculation formula.It is found that the experimental value is highly consistent with the calculated value,and the theoretical model established in this paper can be used to predict the bearing capacity of the shear-reinforced beam in practical engineering.(3)Simulation analysis.The finite element analysis software ABAQUS is used to numerically analyze the shear performance of the RC beam reinforced with RPC steel mesh under load.The size of the established model is exactly the same as that of the specimen.The plastic damage model is used to define the mechanical behavior of concrete and RPC.method" to simulate the secondary force of the reinforcement model.The post-output results mainly include drawing load-deflection curves,determining critical loads,analyzing failure modes,and giving stress distributions.The study found that although there is a certain error between the output results of the finite element software analysis and the experimental values,it still belongs to the normal range.Based on the reinforcement model,a parameter expansion study is carried out to predict the shear performance of RC beams reinforced with RPC reinforcement mesh under more variables.