Study On Axial Compression Behavior Of Semi-precast Composite Concrete Shear Wall

With the development of building industrialization and the need of practical engineering,this paper proposes a new-type composite shear wall suitable for interior wall,and a new-type composite shear wall with thermal insulation material on the basis of previous research.In order to study the integrity performance of this new-type composite shear wall,axial compression tests were carried out on one cast-in-place shear wall and six composite shear walls.The effects of interface connection modes such as setting ribs,setting shear studs and setting CFRP shear connectors on the axial compressive behavior of composite shear walls are studied.Compared with the cast-in-place shear wall,the failure characteristics,mechanical performance,deformation performance and bearing capacity of the specimens under axial load are analyzed.The result shows that the failure modes of specimens can be divided into two types:interface failure and axial compression failure.Among them,interface failure occured in the specimens only with ribs,while axial compression failure occurred in all the other specimens;The bearing capacity of specimens only with ribs on precast concrete plates is small,but the bearing capacity of specimens with shear studs or CFRP shear connectors can be significantly improved.The bearing capacity of the specimens under axial compression can be significantly increased by setting shear studs or CFRP shear connectors on the interface.The bearing capacity of the specimens is more than 84%of the specimens of cast-in-place shear wall;The load-lateral displacement curves of specimens with shear studs or CFRP shear connectors and the load-strain curves at the reinforcement measuring points are the closest to cast-in-place shear wall specimen.It is shown that the bonding strength between prefabricated formwork and cast-in-place concrete can be enhanced by setting shear studs or CFRP shear connectors on the interface;The load-strain curves of steel bar and concrete in composite shear wall with CFRP shear connectors and the cast-in-place shear wall are the closest in the whole loading process.It shows that setting CFRP shear connectors on the interface can effectively improve the integrity performance of the composite shear wall.This paper compares and analyses the research on bearing capacity formula of axially compressed members in various national specifications and relevant scholars.On the basis of the test,the formula for calculating the bearing capacity of this new-type composite shear wall under axial compression is established.The calculated value is in good agreement with the experimental value,which can provide design reference for practical engineering application.The finite element analysis software was used to simulate the mechanical properties of composite shear wall under axial load,the simulation results are in good agreement with the experimental results.On the basis of verifying the rationality of the model,the influence of height-thickness ratio and the spacing of CFRP shear connectors on the axial compression performance of such composite shear wall is further studied.The results show that when the height-thickness ratio increases from 6.67 to 16.67,the ultimate load of composite shear wall specimens varies little,and the axial compressive stiffness of specimens decreases by 57.6%;The ultimate load of specimens decreases with the increase of the spacing of CFRP shear connectors.When the spacing of CFRP shear connectors increases from 210 mm to 840 mm,the ultimate load of specimens decreases by 4%.