Research On Grout-anchor Butt Connection Of Precast Concrete Wall

In recent years,with the deepening of building industrialization and housing industrialization,prefabricated concrete structure has been more widely used.As a construction method in the new era,prefabricated building is an important deployment to help realize the goal of’carbon peak and carbon neutralization’,which is beneficial to improve the construction quality and efficiency,reduce labor force,save energy and reduce emissions.It is the only way to improve quality,efficiency and green development of the construction industry.The reliable connection of prefabricated components is an important guarantee for the promotion and application of prefabricated buildings.In this paper,a reinforced grout-anchor butt joint technology is proposed.The structural performance,connection anchorage mechanism and seismic performance of grout-anchor butt shear wall are studied by uniaxial tensile test,theoretical analysis,finite element simulation and quasi-static test.The main work and achievements of this paper are as follows:（1）The existing reinforced connection technology of prefabricated concrete structure is summarized,and the research status of reinforced connection technology of prefabricated concrete structure at home and abroad is summarized,which provides research basis and analysis ideas for reinforced slurry anchor docking connection.（2）A kind of steel grout-anchor connection technology is proposed.The effective connection of the stressed reinforcement is realized through the joint action of the bellows hole retaining,the rib reinforcement bridge connection and the spiral stirrup constraint,which can reduce the anchorage length of the reinforcement and is easy to operate.（3）18 groups of 54 pull-out joints were designed and manufactured for uniaxial tensile feasibility study test.Based on the feasibility test results,the joint design parameters were improved,and 6 groups of 18 pull-out joints were designed and manufactured for structural improvement test.The experimental study shows that,in order to avoid the fracture failure in the middle of the bar reinforcement,when the bar reinforcement and the connection reinforcement are of the same material,the total cross-sectional area of the bar reinforcement should meet the basic requirements of not less than 1.5 times the cross-sectional area of the connection reinforcement.Under the premise that the section of reinforcement bars meets the basic requirements,when the anchorage length of reinforcement bars is not less than or equal toL_a=0.6L_ae+2d(L_aeis the seismic anchorage length for tensile reinforcement),the reinforced slurry anchor butt joint can meet the strength requirements of grade I joint in the Technical Specification for Reinforced Mechanical Connection（JGJ107-2016）,showing good structural performance.On the basis of experimental research,the design method of grout-anchor docking connection is proposed.（4）ABAQUS bond element is used to simulate the bonding interface between the steel bar and the grouting material,and the joint specimen is modeled and analyzed.Combined with the stress distribution and strain change of the reinforcement bar and the spiral stirrup obtained by experimental research and finite element analysis,the working mechanism of the reinforced slurry anchor docking connection is revealed.（5）In order to explore the seismic performance of the precast concrete shear wall with reinforced slurry anchor connection,the low cyclic reversed load test was carried out on two assembled wall specimens and one cast-in-place wall specimen,and the failure mode,hysteretic performance,skeleton curve,bearing capacity,deformation capacity and energy dissipation capacity of each specimen were compared.The results show that there is little difference between the performance of the assembled specimens and the cast-in-place specimens,and the reinforced slurry anchor butt connection assembled concrete shear wall has good seismic performance.