Experimental Research On Seismic Behavior Of Circular Concrete Columns With Grout-filled Coupling Sleeves

With the development of industrialization of buildings,the prefabricated concrete structure has been vigorously promoted,and the grout-filled coupling sleeves technology is more widely used in engineering.The full grout-filled coupling sleeves is to insert the steel bars to be connected into the cavity at both ends of the sleeve,and then use the special grouting material for micro-expansion to grout to make the steel bars firmly connected,which is convenient for construction and economical.So far,there have been few research on seismic behavior of circular concrete columns with grout-filled coupling sleeves.Based on this,this paper conducts an experimental research on seismic behavior of circular concrete columns with grout-filled coupling sleeves.The main work and achievements are as follows:Firstly,six circular concrete columns with high strength concrete by grout-filled coupling sleeves and three circular ordinary concrete columns were designed and fabricated,and all columns are tested under the low cyclic reciprocating horizontal loads.The difference of seismic behavior between prefabricated columns and ordinary concrete columns under the same conditions was studied.The influence of axial pressure ratio,longitudinal reinforcement ratio,stirrup volume ratio on hysteresis curve,energy dissipation capacity and deformation capacity were analyzed.The results show that:(1)The prefabricated columns and the ordinary concrete columns are all failed in bending,but the sealing layer at the bottom of the prefabricated column is pulled apart when the failure occurs,and there is a certain relative slip between the steel bar and the grouting material;(2)The prefabricated column is more full than the ordinary concrete column,the horizontal bearing capacity is reduced by about 10%,the ultimate displacement is increased by more than 10 mm,the ductility is enhanced;(3)the longitudinal reinforcement ratio increases,the prefabricated column bearing capacity increases,the ultimate displacement is basically unchanged,the ductility is weakened,the energy consumption is enhanced,the intensity attenuation is basicallyunchanged,the stiffness degradation is slowed down;(4)the axial pressure ratio is increased,the bearing capacity of the fabricated column is increased,the ultimate displacement is reduced,the ductility is weakened,the energy consumption is reduced,and the stiffness degradation is slowed down;(5)Based on the reasonable stirrup volume ratio,the stirrup volume ratio has little effect on the seismic performance of the prefabricated column.Secondly,using the analysis software ABAQUS to numerically simulate the prefabricated column,and compare the simulation results with the experimental results to verify the rationality of the model,and increase the longitudinal reinforcement ratio and axial pressure on the basis of a reasonable model.The influence of the longitudinal reinforcement ratio and the axial compression ratio on the seismic performance of the prefabricated column was further analyzed.The simulation results show that the reinforcement ratio of longitudinal reinforcement increases,the bearing capacity of fabricated columns increases,but the greater the reinforcement ratio of longitudinal reinforcement,the smaller the effect of increasing the reinforcement ratio of longitudinal reinforcement on the seismic performance of fabricated columns;When the ratio is increased,the bearing capacity of the prefabricated column is increased,the stiffness is basically unchanged,and the deformability is reduced.Thirdly,comprehensive test results and simulation calculation results,based on the calculation method of previous studies,calculate the horizontal bearing capacity of the circular concrete columns with grout-filled coupling sleeves,and compare with the experimental data and simulation calculation data,the results are in good agreement.However,when the column is in the high axial pressure ratio state,the calculation result has a large deviation.