Study On Compressive Performance Of Precast Concrete Columns Based On Column-column Grouting Sleeve Connection

In order to meet the needs of promoting modular construction,this article proposes a method to improve the connection performance of modular joints,which is to use grouted sleeves to connect the columns in the middle position of the column during the factory prefabrication of beam-column joints.Since the assembly position is in the middle of the column,it can avoid weak beam-column joints and increase the plastic hinge length,thereby improving the energy dissipation capacity of prefabricated concrete columns under seismic loads.However,the compressive performance of prefabricated columns connected in this way is not clear,so it is necessary to study their compressive performance.Firstly,in order to accurately reflect the stress conditions in engineering practice,this article designed five full-scale rectangular section concrete columns for compression tests.Among them,axial compression tests were conducted on the first two full-scale concrete columns,while the remaining three full-scale concrete columns were subjected to large eccentricity compression tests.The focus of the study is to compare the performance differences between cast-in-place and prefabricated concrete columns,and the influence of eccentricity on the large eccentricity compressive performance of prefabricated concrete columns based on column-to-column grouted sleeve connections.In the experiment,the failure mode and crack distribution of the specimens were observed,and the changes in parameters such as deflection,displacement,steel strain,and concrete strain were compared and analyzed.The bearing capacity was calculated according to the requirements of the standard.The test results show that the prefabricated concrete columns based on column-to-column grouted sleeve connections conform to the assumption of a rectangular cross-section.The axial compressive bearing capacity is about 10.4% higher than that of cast-in-place concrete columns,and the ultimate compressive bearing capacity under large eccentricity is about 6.2% lower than that of cast-in-place components.In addition,in the large eccentricity compression test,due to the greater stiffness of the sleeve,the deformation of the specimen is restrained,and the deflection of the prefabricated concrete columns connected in this way at the peak load is smaller than that of cast-inplace concrete columns,and the curvature and concrete strain in the sleeve connection area are also smaller.In addition,this article uses ABAQUS finite element software to simulate and analyze the specimens.The simulated damage,ultimate bearing capacity,and steel strain curve of the specimens are fitted with the test results,and the final results are basically consistent.Based on the validated finite element model,the parameters such as eccentricity,concrete strength,and longitudinal reinforcement ratio are increased for eccentrically loaded members,and parameters such as concrete strength and longitudinal reinforcement ratio are increased for axially loaded members,in order to conduct a more comprehensive study.