Study On Flexural Behavior Of A New Type Of Superimposed Slab Shear Wall

The core task of promoting the development of building industrialization in China is to develop a structural system which is suitable for the development of building industrialization.The superimposed slab shear wall is a semi-prefabricated structure,which is the transition of the concrete shear wall structure system from the site to the complete assembly.The superimposed slab shear wall structure has the advantages of high degree of assembly,good construction quality,environmental protection,energy saving and replacing the traditional template,which is in line with the development requirements of the building industrialization.A new type of superimposed slab shear wall structure is introduced,the two sides of the structure are precast concrete wall panels,and the integral structure is formed by pouring concrete in the middle of the precast slab.The binding property of the new-old concrete interface in the new wall determines the mechanical properties of the wall,the experimental study and numerical analysis of the new concrete interface in the new wall are carried out in this paper.The studies were followed:(1)To study the failure process and failure form,quasi-static tests were carried out for three new type of superimposed slab shear walls.The test result showed that: The failure mode of the new type of superimposed slab shear wall is flexural,it is shown as follows: the longitudinal reinforcement around the edges are buckled seriously,and the concrete is collapsed in the root of the wall.In the state of normal use,the new-old concrete interfaces can effectively ensure the integral performance of the wall.(2)Based on the analysis of the hysteretic behavior,skeleton curve,bearing capacity,stiffness,deformation,energy-dissipating capacity of the specimens,the influence of the ratio of longitudinal reinforcement around the edges and interfance structure on the flexural behavior of the superimposed plate shear wall is studied.The analysis results showed that: The ratio of longitudinal reinforcement around the edges have a great impact on the flexural performance of walls.As the number of longitudinal reinforcement around the edges increased,the flexural bending capacity and energy-dissipating capacity of the specimens will gradually increase,the degradation speed of stiffness will slow down,and the relative deformation between the old-new concrete will decrease.In the state of normal use,the two kinds of interface treatment,the rough surface and the opening of the keyway,can ensure the integrity of the wall.But the keyseating surface treatment can effectively improve the energy-dissipating capacity of the walls,delay the damage process of the wall;and the bearing capacity after the peak level can be maintained bitterly.(3)The finite element model of the superimposed slab shear wall is established by the ABAQUS,the numerical simulation of the new-old concrete interface is carried out by the combination of the Kulun friction model and the cohesive force model,and the failure forms,skeleton curve,the relative deformation of the new-old concrete are analyzed.The results showed that the model and the calculation are proved reasonable sufficiently.(4)Parameter analysis was arried out included the ratio of internal reinforcement and the longitudinal reinforcement around the edges and axial compression ratio.The results indicated that the ratio of internal reinforcement have a little impact on the bearing capacity and the stiffness of the wall,but the increase of the rate of the reinforcement can improve the ductility of the wall.However,the longitudinal reinforcement ratio has a great influence on the bearing capacity and stiffness of the wall,and the increase of the longitudinal reinforcement ratio,the bearing capacity and the initial stiffness of the wall increase as improving the ratio of longitudinal reinforcement,and the ductility is better.The axial compression ratio has a significant influence on the bearing capacity and stiffness of the wall.With the increase of axial compression ratio,the bearing capacity and the initial stiffness of the wall increase greatly,while the ductility decreases.