Experimental Research On Mechanic Behaviour For Grouted Sleeve Connection With The Construction Deviation

The prefabricated bridge adopts factory-produced components to be assembled on site,which fully reflects the advantages of large-scale production and greatly improves the quality and speed of construction.Grouted-sleeve connections technology is one of the key technologies for connection and assembly of prefabricated components,which ensures the integrity and reliability of the structure,and is conducive to the use and promotion of prefabricated assembly structures.This paper systematically introduces the existing reinforced grouting sleeve connection technology from the perspective of engineering application and mechanical performance.As one of the key technologies for prefabricated bridge pier connection,grouted sleeve connection is mainly used to connect the pier pier body with the vertical steel bars in the cap or girder.According to the situation that may occur in actual engineering,construction eccentricity,loading time after grouting,and embedment length of the reinforcement in the sleeve are set to study the influence of various variables on the mechanical performance of grouted sleeve connection.First,the basic mechanical properties of the high-strength grouting material are tested,which provides the basis for the material performance for the research and analysis of the pull-out test of the grouting sleeve connection specimen.Then the test piece is monotonously stretched,and the relative sliding between the steel bar and the sleeve is measured during the test.In addition,the strain distribution on the surface of the sleeve is measured,and the restriction effect of the sleeve on the expansion of the grout is analyzed.The results show that the local bond strength of the locally bonded specimen increases with the age of the specimen and decreases with the increase in the degree of eccentricity of the reinforcement.However,as the length of the steel bar anchorage increases,the effect of the steel bar eccentricity on the mechanical properties of the test piece will decrease.The eccentricity of the rebar has little effect on the mechanical properties of the overall bonded specimen with a long anchoring length.Secondly,the cyclic loading of the grouting sleeve connection test piece is carried out to explore whether the mechanical properties of the test piece will degrade under the action of cyclic load.The test results show that the load capacity and tensile stiffness of the test piece will not be significantly degraded under the number of cycles and stress levels set in the test.Finally,considering the connection performance of reinforced grouting connection joints under earthquake action,the specimens were subjected to high-stress repeated tensile and compression tests and large deformation repeated tensile and compression tests.The results show that after high stress and large deformation,the bearing capacity of the specimen will not decrease,and the residual deformation meets the requirements of the specification.According to the test results,a theoretical analysis of the bond-slip properties of the steel grouting sleeve connection is made.The applicability of the local bond stress-slip relationship recommended in fib Model Code 2010 for ordinary reinforced concrete to the reinforced grouting sleeve connection in this paper is verified.A model of the overall bond stress-slip relationship is proposed,and the accuracy of the model is verified by comparing the experimental data with the model calculation values.