Research On Seismic Performance Of Precast Superposed Concrete Shear Walls With Vertical Joints

Prefabricated concrete structure has the advantages of fast constructive speed,high production quality,green environmental protection,resource saving and so on.It meets the development requirements of China’s construction industry in the new era.China has also issued a lot of relevant policies to promote the development of prefabricated structure.As a new type of assembled structure system,the superposed shear wall structure combines the advantages of assembled structure and cast-in-situ structure,it has a wide range of application prospects.This article aims at the influence of the connection structure between adjacent superposed shear walls at non edge component location specified in current national standard GB/T 51231-2016 Technical standard for assmbled buildings with concrete structure on the seismic performance of superposed shear walls after assembly,an experimental study and finite element analysis were carried out.The main research work and achievements are as follows:(1)Passed the quasi-static seismic test of 3 double-sided superposed shear walls with vertical joints specimens,2 double-sided superposed shear walls without vertical joints specimens and 1 cast-in-situ shear wall specimen,analysis the seismic performance of the precast superposed concrete shear wall with vertical joints,and the effect of different distances between the horizontally connected steel bars at the vertical joints of the superposed wall panels and the inside of the inner and outer prefabricated panels on its seismic performance is discussed.(2)The test results show that the crack distribution of each specimen is basically the same,and the failure mode is bending-shear failure.The cracks on the surface of the superposed shear wall with vertical joints specimens can continuously span the whole joint.he seismic performance of the superposed shear wall specimens with vertical joints and the superposed shear wall specimens without vertical joints(concealed dark columns)and the cast-in-place shear wall specimens are similar.Among the double-sided shear wall test specimens with vertical joints,the DPCW-S-20 specimen has the best ultimate bearing capacity,displacement ductility,and energy dissipation capacity,and the stiffness degradation speed and deformation capacity are basically the same.In the superposed shear wall with vertical joint seam,the test piece DPCW-S-20 has the best effect on the horizontal connection of steel bars,while the test piece DPCW-S-0 has the worst effect on the horizontal connection of steel bars.The change of the position of the horizontal connection steel bar will affect the seismic performance of the vertical shear jointed shear wall and the force transmission performance of the horizontal connection steel bar.It should be ensured that the horizontal connection steel bar has sufficient thickness of the concrete gripping layer.(3)Based on the test results,the numerical simulation analysis of the superposed shear wall specimens with vertical joints is carried out,and the factors such as the axial compression ratio,the lap length of horizontally connected steel bars,the reinforcement ratio of horizontally connected steel bars and other factors are further studied.The results of finite element parameter analysis show that the bearing capacity of the superposed shear wall with vertical joints with the increase of the axial compression ratio significantly increases and the ductility decreases significantly.The shorter the overlapping length of the horizontal connecting reinforcement,the lower the bearing capacity of the specimen.The change of reinforcement ratio of horizontal connection has no effect on the bearing capacity of the structure.Finally,on the basis of summing up the results of this study,some issues for precast superposed shear walls that need further study are proposed.