Finite Element Analysis And Experimental Study On Horizontal Splicing Precast Composite Shear Wall With Concealed Bracing

Precast composite shear wall is a kind of building structure system which is introduced from Germany and suitable for our country.The practical application of this structure system mainly includes design,prefabrication production,transportation and on-site assembly construction,which makes this system has the advantages of industrialization and standardization.Hence,the precast composite shear wall system is not only green,energy saving and environmental protection,but has reliable construction quality and a shorter construction period,which can reduce the comprehensive cost.In recent years,precast composite shear wall system has been actively researched and promoted with the development of housing industrialization,while there are still some difficulties in the application of this construction system.When precast composite shear wall system is used in high-rise buildings,the walls may be so thick that a mass of plain concrete need to be cast in the cavity,which will lead nonuniform stress distribution.In addition,horizontal connections between level structures and vertical connections between vertical structures are relatively weak,which may severely influence the integrity and seismic performance of the structure.All these problems make the use of precast composite shear wall system get restricted,and its development is inevitably limited.In order to improve horizontal connections,integrity and seismic performance of precast composite shear wall,combined with author’s research results of applying concealed bracing in shear walls,a new type horizontal splicing precast composite shear wall with concealed bracing is designed in this paper,namely:assemble the two parts of precast shear wall and embed two X type plate concealed bracings within shear walls’ plastic hinge,and then cast in place at the horizontal connection to form a concealed column.Based on experimental study and nonlinear finite element analysis,a systematic study and analysis on the horizontal splicing precast composite shear wall with concealed bracing is made in this paper,the main research contents are presented as follows:(1)Quasi-static tests of one piece of cast-in-situ shear wall with concealed bracing and one piece of horizontal splicing precast composite shear wall with concealed bracing were carried out,then failure mode,hysteretic loops,skeleton curves,bearing capacity,displacement ductility,stiffness degradation and energy dissipation of the two test specimens were systematical analyzed and compared.Experimental results indicate that the horizontal splicing shear wall almost has the same crack distribution and bending-shear failure mode as the cast-in-situ shear wall,the precast composite shear wall also has the similar bearing capacity and seismic behavior indexes compared with the cast-in-situ shear wall,which makes the precast composite shear wall has good seismic behavior.Horizontal splice connection is reasonable that any vertical crack and relative sliding has not come up along the horizontal splice,which makes the precast composite shear wall has good integrity so that all parts can bear load together.The precast composite shear wall still can obtain good seismic behavior when concealed bracings are merely embedded within shear walls’ plastic hinge.(2)Using ABAQUS program and its nonlinear spring element to simulate the mechanical behavior of the interface between old and new concrete,then the finite element models were established to simulate the performance of two specimens,which are subjected the interaction of axial load and horizontal monotonic load.The finite element calculation results fit well with the experimental results,which shows that the finite element modeling method and parameter selection in this paper is reasonable.(3)On the basis of the effective finite element model,then set axial compression ratio,reinforcement ratio of concealed column,reinforcement ratio of horizontal splicing concealed column and steel ratio of concealed bracing as variables,and investigate these parameters’ effects on shear walls’ peak load capacity,stiffness and deformability.Finite element analysis results show that with the increase of axial compression ratio,bearing capacity and stiffness of shear wall can be improved,but a excessively large axial compression ratio will decrease shear walls’ deformability.Increasing reinforcement ratio of concealed column can significantly improve shear walls’ bearing capacity.There only is a tiny improvement of shear walls’ bearing capacity when increase reinforcement ratio of horizontal splicing concealed column,which indicts that should use smaller diameter reinforcement in horizontal splicing concealed column from the economic point of view.Increasing the steel ratio of concealed bracing can increase the bearing capacity and ductility of shear wall.