Study On Connection Performance Of Grouted Sleeve Based On Surfacing Formed Rib

Building industrialization is the development trend of the construction industry,and precast concrete structure is one of the main structural forms promoted.The joint between precast concrete components is the key part to effectively connect various components and ensure the overall performance of the structure,and the most important is the connection of rebar between members.At present,the grouted-sleeve connection technology is widely used at home and abroad to realize the butt connection of rebar between components.A large number of engineering practices and tests also verify the feasibility of production and construction and the reliability of connection performance.However,the existing grouted sleeves still have many problems,such as less types and higher prices.At the same time,the domestic systematic research on the grouted-sleeve connection is obviously insufficient and the design theory is deficient,which limits the development of precast concrete structure in China to a certain extent.Inspired by the additive manufacturing concept of 3D metal printing technology,the author proposes a new type of grouted sleeve that forming circumferential ribs on the inner wall of a seamless steel pipe by using surfacing welding.In this study,sleeves were processed via this method and 37 joint specimens with different parameters were fabricated.Refinement tests and theoretical analysis were carried out to study the grouted-sleeve connection performance under uniaxial tension and repeated tension-compression,analyze the working mechanism of grouted-sleeve connection,reveal the influence of various parameters on the connection performance of grouted sleeve splices,and improve the core technology and design theory of grouted-sleeve connection,in order to help the development of precast concrete structure in China.The main research work and achievements of this thesis are as follows:(1)On the basis of summarizing the existing grouted sleeve products and research status at home and abroad,a new type of grouted sleeve based on surfacing formed rib and its manufacturing method is proposed,which enriches the types of existing grouted sleeves.The sleeve is made of low alloy seamless steel pipe as the base material,and circumferential ribs are overlaid on the inner wall at intervals.The utilization rate of processing materials is high,and parametric control and automatic production can be realized.(2)Through uniaxial tension and repeated tension-compression tests,the failure mode,deformation performance,sleeve and rebar strain distribution law of grouted sleeve splices are systematic studied.At the same time,parametric tests and comparative analysis were carried out to study the influence of parameters such as the inner cavity of sleeves,the anchorage length,and the grout strength on the mechanical properties of grouted sleeve splices.(3)According to the results of tests,the stress transfer mechanism and failure mechanism of grouted-sleeve connection are analyzed,the distribution of bond stress at different positions of rebar in the sleeve is studied,and the bond-slip constitutive relationship about the position is proposed.Based on the contact analysis theory,ABAQUS finite element software is used to model and analyze the grouted sleeve splices,the numerical simulation results are in good agreement with the experimental results.(4)According to the experimental data,theoretical analysis and numerical simulation results,the parameter design suggestions of the new grouted sleeve joint are given.The empirical calculation formula of joint bearing capacity based on the statistical analysis of test results is fitted,the calculation formula of joint bearing capacity based on the bonding stress distribution model are deduced,and the design method of this kind of new grouted sleeve joint is put forward,which can provide a reference for the optimal design of grouted sleeve joint.