Study On Uplift And Shear Resistance Of Box-connected Assembled Shear Wall Joints

On the new journey,with the continuous deepening of China’s Rural Revitalization Strategy,the level of beautiful rural construction needs to be comprehensively improved.In this context,prefabricated housing is the inevitable development trend of low and multi-storey self built rural housing in the future.Box connection has the advantages of high installation efficiency,convenient quality detection of connection nodes,and less environmental pollution,which is in line with China’s national conditions,and has a broad application prospect in low and multi-storey prefabricated housing.As far as the prefabricated housing with box connection is concerned,the reliable pull-out and shear performance of the connection node is the key to ensure its mechanical performance and engineering application.In this thesis,based on the previous research of the box connection fully assembled wall slab series products,in order to improve the pull-out and shear bearing capacity of the box connection node and change the pull-out and shear failure mode of the connection node,the finite element numerical simulation method is used to study the pull-out and shear properties of the connection.The main research contents of this thesis are as follows:(1)Based on the verification of the pull-out test of embedded sleeve end specimen and embedded connection box end specimen,the model of the joint box sleeve combination specimen is established.The screw strength,sleeve strength,sleeve U-shaped reinforcement strength,sleeve U-shaped steel bar diameter,connection box U-bar diameter,sleeve cross bar diameter,connection box bottom plate thickness,connecting screw diameter,double cross bar sleeve to junction box sleeve are studied The influence of the pull-out performance of the composite specimen.The results show that the ultimate bearing capacity of the combined drawing model can be greatly improved by increasing the diameter of the sleeve cross bar,and the failure mode of the model can be changed;the change of other parameters has limited effect on the ultimate bearing capacity and ductility of the model,and the failure mode of the model can not be changed.(2)Based on the analysis results of the parameters of the pull-out composite specimen of the joint box and sleeve,the better joint box and sleeve with better comprehensive performance of anti pull performance and economic performance is proposed.The results show that: compared with the model with the initial parameters,the model with the better connection device can save 50% of the material for the bottom plate of the connection box,63.56% of the material for the U-shaped steel bar of the connection box,96.70% of the bearing capacity and 214.40% of the failure displacement,and the failure mode of the model changes to the sleeve U-shaped steel bar being pulled out.(3)Based on the test of prefabricated concrete shear wall structure with box connection,the connection box is replaced by the connection box in the second chapter of this thesis for simulation analysis.It is found that the horizontal joint is the weak position of the model.In order to put forward a more reasonable connection scheme,the number of screws and screw diameter were changed for parameter analysis,and the optimal scheme was put forward.The results show that: increasing the number of screws can not change the failure mode of the shear wall,but the diameter of the screw increases from 16 mm to 24 mm,and the failure mode of the shear wall changes to bending failure.According to the simulation results,two screws with diameter of 24 mm and spacing of 900 mm are selected.(4)Based on the optimal scheme,the influence of reducing the cost of connection box on the shear performance of shear wall is studied,so as to put forward a better scheme.Finally,based on the optimal scheme,the influence of axial compression ratio and wall thickness on shear performance of shear wall is studied.The results show that: the shear performance of the shear wall will be reduced by optimizing the cost of the connection box,so the optimal scheme will not be changed,and the optimal scheme will still be used;the shear performance of the shear wall will be reduced by increasing the axial compression ratio and reducing the wall thickness.