Experimental Study On Flexural Performance Of Precast Concrete Shear Walls With Mortise-tenon Joints

The structure of precast concrete shear wall with mortise-tenon joints is a new type reinforced precast concrete shear wall structure without protruding steel bars at the side.The wall is the basic assembly unit of precast concrete members with horizontal grooves.In this paper,the mortise-tenon joint performance and the seismic performance of the wall are systematically studied.The main conclusions:(1)Experimental study on flexural performance of precast shear walls with vertical joints in different forms.The pseudo-static tests of one cast-in-place RC shear wall,one precast concrete shear wall with straight joints and one precast concrete shear wall with mortise-tenon joints under constant axial force are carried out.The study shows that the horizontal reinforcement strains on both sides of the mortise-tenon joints are basically the same,and the walls on both sides of the joints basically have no relative deformation before the peak load.During the failure,the relative horizontal and vertical deformation is only 0.12 mm and 0.79 mm.The ratio of the relative slippage of the wall to the horizontal displacement of the loading point is only 2.1%.The joint connection is reliable,ensuring the overall performance of the wall.The flexural capacity and stiffness of precast concrete shear wall with mortise-tenon joints are basically equivalent to that of cast-in-place RC shear wall.When the lateral longitudinal bar of the edge member yields,the longitudinal bar strain of the bottom section conforms to the assumption of the plane section,which can achieve the design goal of "equivalent to cast-inplace".The ratio of flexural deformation before joint cracking is basically equivalent to that of cast-in-place RC shear wall.In the case of failure,the concrete at the mortise-tenon joints is spalling,which reduces the area of concrete crushing at the root and improves the deformation capacity of the wall.The precast concrete shear wall still maintains good vertical bearing capacity at the vertex displacement angle 1/50.(2)Experimental study on flexural behavior of precast concrete shear wall with mortisetenon joints in different ratio of longitudinal reinforcement.The pseudo-static tests of three precast concrete shear wall with mortise-tenon joints under constant axial force are carried out.The study shows that increasing the ratio of longitudinal reinforcement of the edge members can increase the peak load of the wall,have a positive effect on improving the ductility of the wall,and can improve the deformation capacity and total energy dissipation capacity of the wall.After increasing the ratio of longitudinal reinforcement,the failure area is more concentrated in the joints of the wall,which delays the crushing of the concrete at the root.(3)A numerical calculation model of precast concrete shear wall with mortise-tenon joints is established.The numerical model of precast concrete shear wall with mortise-tenon joints is established by finite element software ABAQUS.The numerical simulation results are in good agreement.The skeleton curve and wall failure pattern are basically the same as the test results.On this basis,influence of different coaxial pressure ratio and tooth groove size are studied.(4)The frame curve three-fold model of precast concrete shear wall with mortise-tenon joints is established.The yield point,peak point and limit point are taken as the characteristic points of the model to calculate the bearing capacity and displacement of each characteristic point.The calculated results are basically consistent with the experimental results.The normal section bearing capacity of eccentrically compressed precast shear wall with mortise-tenon joints can be calculated by using Technical specification for concrete structures of tall building.The calculated result is conservative.