Experimental Study On Mechanical Properties Of Semi-grouting Sleeve Connection

With the "13th Five-Year Plan" proposed to promote the modernization of the building industry,to spread fabricated building,and to construct the industrial base of the fabricated building vigorously,the theoretical researches and engineering applications of the fabricated building in our country have entered a stage of rapid development.For the structure of fabricated building,the most important problem is the connection between prefabricated components.In our country,the main connection between the rebar of prefabricated components includes the grouted sleeve connection and grouted and splicing connection.Due to the grouted sleeve connection has excellent performance and is easy to construction,it is widely used.In this paper,on the basis of summarizing the experiments of grouted sleeve connection at home and abroad,the influences of different factors on the mechanical properties of semi-grouted sleeve specimens are studied.The main research contents and results are as follows:1.Four kinds of influencing factors are considered in the experiments,namely the strength of grouting material,the diameter of the rebar,the material of the sleeve,and the length of the anchorage.Then,72 specimens with different parameters are designed and the uniaxial tensile experiments of each specimen are performed.According to the experimental results of the ultimate bearing capacity,load-displacement curve and the stress-strain curve of the tube wall,the influence factors of the mechanical properties of the specimens are parametrically analyzed.The analysis results show that increasing the length of the anchorage and the thickness of the sleeve properly can effectively reducing the strain of the tube wall.Then,increasing the length of the anchorage and the diameterof rebar properly can effectively improving the ultimate bearing capacity of the semi-grouted sleeve connection specimens.2.Based on the theory of thick-walled cylinders,the force transfer processes between the sleeve and the grouted material and between the rebar and the grouted material are analyzed.The relationship between the axial force of the rebar and the longitudinal and transverse stress of the sleeve is derived.Moreover,the relations between the thickness of the sleeve,the diameter of the rebar and the length of the anchorage are obtained.On the basis of the study on the bond-slip between rebar and concrete at home and abroad,the influences of grouted material strength on the bond stress between rebar and grouted material are analyzed.Finally,the relations between the ultimate bearing capacity of the specimen and the length of the anchorage,the diameter of the rebar and the strength of the grouted material are given.3.Using the ANSYS Workbench software,the finite element method on the semi-grouted sleeve specimens with different parameters is carried out.Calculating the strain of the sleeve wall at different positions and the ultimate bearing capacity of the specimens,and compare them with the experimental value.The results show that the ultimate bearing capacity and the wall strain obtained by finite element software agree well with experimental values.