Research On Seismic Behavior Of A New Type Of Precast Column With Intermediat Bolt Connection

In recent years,the industrialization of construction has become an inevitable trend in the development of the construction industry.The fabricated structure is highly respected by the construction industry for its short construction period,low labor input,high production efficiency and green construction.Since the fabricated structure is prefabricated and assembled,there are connection nodes between the components,so whether the reliability of the connection node meets the requirements and whether it affects the seismic behavior of the fabricated structure compared to the cast-in-place structure have become the focus of research for scholars at home and abroad.The connection form of precast components is divided into dry connection and wet connection.In the past researches,the research results of the bolt connection technology are relatively few,and the development is still immature,so further research is still needed.Generally,the bending moment at the middle of the column is small and the bending moment at the end of the column is the largest.If the connection position of the precast column is set at the middle of the column,the joint node will bear a small bending moment,and the connection reliability is more easily guaranteed.At the same time,the connection node of column and column is far away from the complex stress area of the connection node of beam and column,and the respective force performance of the two types of nodes will be more easily guaranteed.In summary,this paper studies the seismic performance of the precast column with intermediate bolt connection.Firstly,this paper designs three precast columns with intermediate bolt connection under different axial compression ratios,one precast column with bottom bolt connection,and one precast column member for improving the concrete strength grade of the lower half column.And then pseudo-static tests are carried out for these components.By analyzing the bearing capacity,stiffness,displacement ductility factor,energy consumption of each component,the differences in seismic behavior are compared.Secondly,the SEISMOSTRUCT finite element software is used to numerically analyze the precast columns of the types studied in this paper.Some components in the test are modeled.The effectiveness of the numerical simulation method is verified by the comparison of test results and numerical simulation results.Then,the same numerical simulation method was used to establish seven precast column and cast-in-place models,and differences of the seismic behavior were compared and analyzed.The results show that the seismic behavior of precast column with intermediate bolt connection is basically the same as that of cast-in-place column.The reliability of joint and seismic behavior of precast column with intermediate bolt connection are better than that of precast column with bottom bolt connection.As the axial compression ratio increases,the rate of the bearing capacity and stiffness degratdation of the precast columns become faster,the ductility performance deteriorates,but the energy consumption capacity enhances.When the concrete strength grade of the lower half column of precast column with intermediate connection is improved,the ultimate bearing capacity of the components improve,but the energy consumption capacity weakens.Finally,suggestions for the shortcomings in the research content of this paper are made,and the related researches that can be carried out are presented.