Experimental Study On Seismic Behavior Of Precast Concrete Shear Walls With Grout Sleeve Splicing

Building industrialization is the main development direction of the construction industry in our country.Due to the advantages of high production efficiency,convenient and reliable connection,precast grout sleeve splicing have become the main reinforcement connection adopted by precast concrete shear wall structures in our country.However,the size of the grout sleeve is generally large and bulky,resulting in higher cost which is one of the main factors restricting the development of precast concrete shear wall structures.In this paper,different types of miniature grout sleeves are designed and manufactured.Based on the research of their connection and anchorage behavior,the miniature grout sleeves are applied to precast concrete shear wall structures to study their seismic behavior.Combined with the analysis of anchorage reliability,the paper puts forward the application suggestion of the precast concrete shear walls with grout sleeve splicing.The main contents are as follows:(1)The drawing test of 59 miniature grout sleeves were completed,and the connection behavior and anchorage behavior were studied.The results show that grouting material strength,anchorage length and the sleeve diameter have an influence on bond strength between the reinforcement and the grouting material;The bond strength calculation formula and the bond slip curve model under the action of lateral pressure stress are obtained.The miniature grout sleeves meet the requirements of "Application Technology of Reinforcing Barrel Grouting Connection Regulations " on the sleeve grouting joints under uniaxial tensile strength requirements.(2)The low cyclic loading tests of two small-sized sleeve grouting joint full-scale shear wall specimens have been completed,and the seismic behavior of precast concrete shear walls with miniature grout sleeves were studied.The study shows that miniature grout sleeves can effectively transfer the reinforcement stress,and have good connection behavior,which can work with the whole specimen as a whole;The shear walls with miniature grout sleeves have good seismic behavior;The final failure modle of shear wall specimens were flexural failure,without shear slip of the whole;The hysteresis curve is full,the phenomenon of pinch shrinkage is not obvious,and has a good energy dissipation capacity.After reaching the peak load bearing capacity,the specimen retains high bearing capacity and slows down,showing good plastic deformation capacity.The limit displacement angle is up to 1/54,which meets the requirements of elastic-plastic displacement angle of shear wall structure under major earthquake as specified in the code,and the deformation and ductility of specimens have good behavior.(3)The anchorage reliability of connecting steel bar and grouting material is analyzed by center point method and checking point method,and compared with the requirements of the code.The results show that the anchoring length calculated by center point method and checking point method are basically same.It is suggested that when the connecting bar diameter is small(12-14mm),the value of anchorage length can be taken as l=8d;when the diameter of the connecting bar is large(16-28mm),take anchor length l =7d.(4)According to the experimental research and theoretical analysis,with reference to the current specification,the application suggestions of precast concrete shear wall with grout sleeve splicing are put forward.The research shows that the normal section,oblique section and horizontal joint bearing capacity of the precast concrete shear wall with miniature grout sleeves can be designed and calculated by the formula of the current standard;The design method of grouting sleeve proposed in this paper can provide reference for the design of grouting sleeve;In order to save the materials,the anchorage length of the inserted reinforcement can be appropriately reduced under the premise of ensuring the construction quality.The related work completed in this paper can further enrich the research results of precast concrete structures,provide a basis for revision of relevant codes of precast concrete structures,and promote the popularization and development of precast concrete structures.