Study On Seismic Performance Of Corrugated Pipe Through-Hole Precast Column With Different Grouting Defects

In response to the new concept of national green development,building industrialization has gradually become a major development trend in the development of the construction industry.On the one hand,building industrialization is conducive to reducing environmental pollution and meeting the needs of China ’s development.On the other hand,it can reduce labor input,reduce labor intensity and speed up the construction process.Therefore,it is vigorously promoted in the transformation and upgrading of the construction industry.For the assembled frame structure,the reliability of the connection between the upper and lower prefabricated columns is the key link to determine whether the assembled structure can be equivalent to the cast-in-place.At present,the prefabricated components are mainly connected by sleeves,but the sleeve connection has high requirements for construction accuracy,and the grouting is prone to slurry leakage.Therefore,this paper proposes a new connection method-corrugated pipe through-hole connection.This connection method can reduce the construction accuracy due to the large aperture of the bellows,and the force transmission is clear,which provides a new design concept for component connection.Based on the experimental and theoretical analysis,the seismic performance of corrugated pipe through-hole prefabricated columns is studied.The main research and results are as follows :In this paper,one cast-in-place column and three corrugated pipe through-hole precast columns were designed and manufactured.Through low-cycle reciprocating test,the influence of different grouting defect rates of corrugated pipes on seismic performance was comprehensively compared and analyzed.The test results show that :(1)Precast columns are different from cast-in-place columns in bending and shear failure,but brittle failure occurs.The reason is that stirrups cannot effectively restrain the lateral deformation of bellows in the later stage of loading,and finally the members are destroyed due to the expansion of stirrups.(2)When the grouting defect rate in the corrugated pipe is less than 30 %,it has little effect on the corrugated pipe through-hole prefabricated column,but the defect rate will reduce the bearing capacity of the component to a certain extent;(3)The ultimate displacement angle of each specimen can meet the seismic requirements,so the deformation capacity is relatively good.It should be noted that with the increase of grouting defect rate,the ductility of the component shows a decreasing trend;(4)Increasing the grouting defect rate of the component will reduce the seismic indexes such as energy consumption and lateral stiffness of the component to varying degrees,but it has little effect on the strength degradation,and the specimen can basically maintain a stable horizontal bearing capacity.Through the finite element software ABAQUS,the numerical simulation of castin-place columns and non-defective prefabricated columns is carried out.Compared with the test results,the rationality of the model is verified from the aspects of specimen damage,skeleton curve and specimen ductility.Based on a reasonable model,the influence of diameter of longitudinal reinforcement,eccentricity of longitudinal reinforcement and axial compression ratio on the corrugated pipe through-hole prefabricated column is analyzed.The results show that when the diameter of the corrugated pipe is 60 mm,the axial compression ratio of the prefabricated column should not be greater than 0.656,and the diameter of the longitudinal reinforcement should not exceed 18 mm.The eccentricity of longitudinal reinforcement has little effect on the corrugated pipe through-hole prefabricated column,and it is suggested that the longitudinal reinforcement arrangement should be in the form of central arrangement.On the basis of the test,the test fitting method is used to establish a unified double broken line skeleton curve model of the prefabricated column.It is verified that the model can better match the test results,and the unloading stiffness of the component is fitted by regression,and the restoring force model of the corrugated pipe through hole prefabricated column is proposed.It is verified that the restoring force model of corrugated pipe through-hole precast column is in good agreement with the experimental results.