Experimental Study On The Seismic Performance Of Assembled Monolithic Shear Walls Of Mortise-tenon Joints With Vertical Joints

Assembled monolithic concrete shear walls with mortise-tenon joints is a new type of fully precast concrete shear wall structure,which uses precast concrete wall panels with transverse grooves and vertical holes as the basic assembly unit,and it is easy to produce,transport,and install.This paper uses a combination way of experimental,numerical simulation,and theoretical analysis to study the seismic performance of the assembled monolithic concrete shear walls with mortise-tenon joints with vertical joints,and the calculation formula for the shear bearing capacity of vertical joints discussed.The main work of this paper and the main results obtained are as follows:(1)The pseudo-static test of 3 pieces of assembled monolithic concrete shear walls with mortise-tenon joints with a shear span ratio of 1.5 and a comparison specimen of cast-in-situ reinforced concrete shear wall was carried out to explore the seismic resistance of the new type of shear wall.Performance and the influence of different mortise-tenon board structures and horizontal distribution of steel reinforcement ratio on the seismic performance of the new shear wall.Research shows:Assembled monolithic concrete shear walls with mortise-tenon joints has good seismic performance,the rate of stiffness degradation is less than cast-in-place shear wall,and the cumulative energy consumption is greater than that of cast-in-situ shear wall signally,the ductility coefficient exceeds 3.80,and the limit displacement angle is greater than 1/60.Meet the specification requirements.The failure mode of the assembled monolithic concrete shear walls with mortise-tenon joints is different from the cast-in-place shear wall.The cast-in-place shear wall is mostly damaged at the root of the wall,and the concrete at the root of the wall is crushed under peak load;The mortise-tenon shear wall’s area is mainly concentrated at the bottom of the transverse groove of the tenon-and-mortise board and the root of the protruding part.The concrete at the root of the wall basically has no crushing phenomenon under the peak load,and two long cracks are formed in the middle of the mortise-tenon shear wall after the peak load.The wall enters the force-bearing stage of the wall-column combination,which greatly improves the deformation performance of the mortise-tenon shear wall.The inner edge of the longitudinal hole of the mortise-tenon plate is flush with the inner side of the transverse groove,which can delay and reduce the damage of the mortise-tenon joints.There are fewer cracks in the flat test piece,and the area and degree of concrete crushing at the root of the wall is smaller.It has little effect on the beari ng capacity of the mortise and tenon joint assembly integral shear wall.The reinforcement ratio of the horizontal steel bars will affect the damage degree of the Assembled monolithic concrete shear walls with mortise-tenon joints.The increase of the reinforcement ratio will increase the damage degree of the mortise-tenon joint to a certain extent and has little effect on the bearing capacity.(2)The finite element software ABAQUS was used to numerically simulate the assembled monolithic concrete shear walls with mortise-tenon joints,and the results of the numerical model which considering the restraint effect of stirrups and the force properties of the joint surface are in agreement with the experimental results;Based on the this,the influence of different parameters on the seismic performance of the assembled monolithic concrete shear walls with mortise-tenon joints is analyzed,and the following conclusions are drawn:The longitudinal hole size has little effect on the bearing capacity of the assembled monolithic concrete shear walls with mortise-tenon joints but has a significant influence on the overall damage of the joint.It is recommen ded that the inner edge of the longitudinal hole of the mortise and tenon plate be flush with the inner side of the transverse groove.The increase of the longitudinal reinforcement ratio of the edge members will increase the peak bearing capacity and has little effect on the peak displacement angle.The ductility will be worse at higher reinforcement ratios,and the specimen failure will be earlier;The effect of the horizontal reinforcement ratio on the seismic performance not much;increasing the axial compression ratio can improve the bearing capacity of the specimen,but it will reduce the deformation performance of the specimen.(3)The factors affecting the shearing performance of the mortise-tenon joint assembly integral shear wall are analyzed and summarized,and the formula for calculating the shear strength of the mortise-tenon joint is proposed and compared with the experimental data in the literature.