Mechanical Properties Of Eccentric Compression Of Reinforced Concrete Columns Strengthened With LRS-FRP

In recent years,Fiber Reinforced Polymer(FRP)has achieved corrosion resistance,fatigue resistance,light weight and high strength,convenient construction,low maintenance costs,and good chemical stability.Wide application.However,several FRP materials currently being studied are limited by the seismic structure reinforcement because of their high elastic modulus and low tensile fracture strain(1.0% ~ 3.0%).However,the recent emergence of Large Strain FRP(Large-Rupture-Strain FRP(LRS-FRP))has low elastic modulus and large tensile fracture strain(fracture strain ≥5%),which complements several FRP materials that are mainly studied.Therefore,the research on the sublimation technology of FRP-reinforced concrete to the LRS-FRP-reinforced technology is studied.Columns,as important force-bearing members,play a vital role in the structure.For ordinary plain concrete columns and reinforced concrete columns,reinforcement with large strain FRP(LRS-FRP)can greatly improve the ductility and mechanical properties of plain concrete columns and reinforced concrete columns.Due to the fact that the axial load in the strict sense of the building structure does not exist in the engineering practice,most of the building structures have the function of eccentric load,and the uncertain factors of the seismic load have led to more types of loads on the structure.Therefore,based on the above ideas,this paper carried out experimental research and theoretical analysis on the mechanical properties of RC columns strengthened by LRS-FRP under eccentric compression,and established a stress-strain constitutive model.The main contents are as follows:(1)Design of test plan and basic mechanical properties of test materials: test piece size,4 kinds of working conditions,arrangement of measuring points,placement of rebar strain gauges,loading system,cyclic loading operation,determination of eccentricity,determination of LRS-FRP The relationship between the ultimate tensile strength and the breaking strain,the compressive strength of the concrete,and the stress-strain of the steel bar;(2)Experiments on reinforced concrete columns strengthened by LRS-FRP under different eccentricity under static load were studied,and load displacement curve,stress-strain curve,bending moment curve,central hoop strain,and concrete cracking strain were obtained(radar chart).The relationship between the strain of the reinforcement and the compression of the specimen,and the effect of the buckling of the reinforcement on the cracking strain of the concrete.And,compared with reinforced concrete columns and plain concrete columns with or without LRS-FRP constraint and with a layer of LRS-FRP constraint,a comparative analysis of the strengthening mechanism was performed;(3)The constitutive model of reinforced concrete columns strengthened by LRS-FRP under different eccentricity under static load was studied.