Experimental Study On Mechanical Behavior Of Assembled Monolithic Shear Walls With Mortise-tenon Joints Under Moderate-to-high Shear Ratio

In order to meet the requirements of the structural integrity of prefabricated buildings and the seismic performance of their components,the reliable reinforcement connection methods and reasonable structural measures of combining precast components with post-cast concrete are generally adopted in the joint connection technology of assembled monolithic concrete structures.The structure system of assembled monolithic concrete shear walls with mortisetenon joints(hereinafter referred to as mortise-tenon shear wall)adopts non-contact laps joint to bars.At the same time,the edge structure of prefabricated wall panels is innovatively designed,and the joint technology of mortise-tenon joints suitable for horizontal connection of prefabricated wall panels in prefabricated shear wall structures is put forward.In this paper,the seismic behavior of mortise-tenon shear walls with cast-in-place edge members under medium and high shear-span ratio is studied,which mainly includes bearing capacity,deformation,stiffness,energy consumption and the change and development of failure mode.At the same time,connection behavior of mortise-tenon joints are analyzed briefly.The detailed content is as follows:The quasi-static tests of two tenon-mortise shear walls with different axial compression ratios and one reinforced concrete shear wall were carried out under medium and high shearspan ratio.The test results show that,under the same design parameters,the stiffness of mortise-tenon shear wall at the early loading stage is equivalent to that of cast-in-place shear wall,and the mortise-tenon joints maintain a good connection performance,which basically has no influence on the stiffness of wall at the early loading stage.After the peak point,the hysteresis curve of the mortise-tenon shear wall is fuller than that of cast-in-place wall,the horizontal bearing capacity and stiffness degradation is slower,and the wall has better ductility and greater ultimate deformation capacity.When the axial compression ratio of mortise-tenon shear wall specimens increases,the bearing capacity of the wall increases,and the stiffness increases at the early loading stage.However,the degradation rate of bearing capacity and stiffness accelerates,the peak and ultimate displacement decrease,and the ductility of the wall becomes worse.In terms of failure modes,increasing the axial compression ratio made the cracks at the mortise-tenon joint and the central vertical through hole develop more rapidly.When the ultimate state was reached,the failure degree of the mortise-tenon joint was more severe than that of the benchmark specimen,and a crack zone had been formed at the central vertical through hole.The quasi-static tests of two mortise-tenon shear walls with different reinforcement ratios of horizontal distribution of steel bars were carried out to study the effect of reinforcement ratios on the seismic performance of cast-in-place edge member walls under medium and high shear-span ratio.The experimental results show that with the increase of the reinforcement ratio,the stiffness of mortise-tenon shear wall increases in the early loading period,the horizontal bearing capacity and the peak displacement increase,the ductility of the wall is better,and the energy dissipation capacity is enhanced.However,the degradation rate of bearing capacity and stiffness is accelerated,and the ultimate displacement decreases.In terms of the failure process,the cracks at the mortise-tenon joints develop more slowly than those of the benchmark shear wall,the relative deformation of the walls on both sides of the joints decreases,and the horizontal distribution of steel bars effectively limits the cracking of the new and old concrete joints at the mortise-tenon joints.The numerical model of shear wall with mortise-tenon joints under medium and high shearspan radio is established by ABAQUS,and simulation of the shear walls under monotonic loading the basic mechanical properties,extraction of load-displacement curve,compare with skeleton curve of quasi-static tests.Based on the verified the correctness of the model,the three piece of mortise-tenon shear walls set different ratio of longitudinal reinforcement are simulated under monotonic loading.The results show that the horizontal bearing capacity and deformation capacity of the walls increase with the increase of the longitudinal reinforcement ratio,and the increase of the longitudinal reinforcement ratio can limit the development of cracks in the edge members and reduce the tensile failure of concrete.