Study On Seismic Performance Of Precast RC Shear Wall With New Types Of Connection

Reinforced Concrete(RC)shear wall structure is the most common structure in highrise buildings in China.In recent years,RC prefabricated shear wall structure has been widely concerned,utilizing its high degree of industrialization,construction efficiency,high quality of construction products,environmental protection and other advantages.An effective and safe connection to join the precast parts together is the key point of the precast RC shear wall structure.This paper puts forward two innovative types of connection for RC prefabricated shear wall,which are the rebars connected with pressed sleeve splicers and bolted-plate connection.The innovative connections can solve the existing problems of testing difficulties on the reinforced grouting sleeve connection quality,grouting sleeve size too large in the concrete wall section and so on.The seismic performance of precast RC shear walls using pressed sleeve rebar splicers and bolted-plate connection has been studied.The main research contents are as follows:1)An innovative type of precast RC shear wall connected by extruding steel sleeves and rebars is proposed.To ascertain the feasibility and seismic performance of the precast RC shear wall,a series of pseudo-static tests of 7 precast shear walls and 2 cast-in-situ shear walls were completed.The hysteresis curves,characteristic points and the strains of the steel bars of the specimens were analyzed.The test results showed that the precast and cast-in-situ RC shear wall specimens all failed in bending.In the case of simplifying the arrangement of steel bars,the cold-extrusion sleeve connection could effectively transmit the tension pressure of the steel bar.The shear walls connected by extruding steel sleeves and rebars had a satisfactory seismic performance.The bearing capacity and stiffness were reliable,and the energy dissipation capacity and ductility were close to the cast-in-situ wall.2)An innovative type of precast RC shear wall vertically connected by a wet joint at the bottom of the precast wall panel,with the wet joint consisting of the bolt-plate connection(BPC)and the post-casting concrete to achieve structural integrity is explored.A cast-in-place shear wall and five precast shear walls with various parameters,including the ratio of shear span ratio and the axial compression ratio,were fabricated.Lateral cyclic loading tests were conducted on the precast shear wall specimens,as well as the cast-in-place counterpart,to examine their seismic performance.The damage modes,hysteretic behaviour,stiffness degradation,energy dissipation capacity,shear deformation,and the strains of the reinforcements and BPC,were fully reported and discussed.The test results show that the BPC can effectively transmit the combined actions of compression load,bending moment and shear force from the precast wall panel to the foundation beams of the specimen,and avoid slippage at the BPC area.Compared with the cast-in-place shear wall specimen,the reference precast shear wall specimen with BPC exhibited fuller hysteresis curves with higher lateral resistance,larger ultimate deformation and better energy dissipation capacity.3)The finite element models of two innovative types of precast RC shear walls are developed in ABAQUS to simulate the hysteresis response.Data from cyclic tests of a precast wall and a cast-in-place benchmark wall were used to validate the numerical model.With reasonable parameter selection,the numerical results are in good agreement with the measured response.The validated ABAQUS model is used in a parametric study to investigate the effects of wall aspect ratio,axial load level and longitudinal reinforcement ratio in the boundary elements on the monotonic response of the precast shear walls.4)Based on the test and numerical simulation,the bearing capacity calculation methods for two innovative types of precast RC shear wall are proposed respectively,and the reliability of the methods is verified by comparing them with the test results.Then the steel efficiency analysis of the precast RC shear wall with different connection modes is carried out,which provides a reference for the selection of different connection modes in the application on precast RC shear wall structure.The research results of this two innovative types of precast RC shear wall connection schemes,the force transfer mechanism at the joint,the design calculation method and the application analysis can provide a reference for the comparison and design of RC prefabricated shear wall structures,and have important academic value.