Study On The Application Technology Of Shear Walls With Precast Concrete Hollow Moulds

The core motivation of housing industrialization is the innovation and development of precast structures. Shear wall with precast concrete hollow moulds is a new type of precast shear wall, which is composed of precast concrete slabs with two-way holes( “precast concrete hollow moulds” for short) and the cast-in-place concrete. Based on review research, experimental study and finite element analysis, the application technologies of the new type precast shear wall which contain the connection between the upper and lower floors and precast boundary elements are studied to provide the basis for the engineering practice of shear wall with precast hollow moulds. The main contents and conclusions, suggestions are as follows:(1) Researches on shear resisting mechanisms and calculation formulas of shear resisting capacity of horizontal joints in precast reinforced concrete shear wall structures are reviewed. The results indicate that the bottom horizontal joint interface of shear wall with precast concrete hollow moulds belongs to composite rough interface, the shear resisting capacity of which can be predicted by the formula in JGJ 1-2014 to check whether splice rebars can meet the horizontal shear resisting requirement.(2) Uniaxial tension tests of six specimens with indirect lap splice and finite element simulation have been completed. A splice length which is equal to 1.5 times the design anchorage length of splice rebar is suggested, the predicted loading curves by finite element simulation are in good agreement with test results, the predicted stress distributions of splice rebar are basically in accordance with test results.(3) Quasi-static tests of four full scale shear wall specimens with precast concrete hollow moulds and splice rebar connection and monotonic tests of two wall specimens have been carried out. The finite simulation and parameter study of tests have been completed by software ABAQUS. The test results indicate that the splice rebar connetion and the chosen splice length can meet requirements. Both splice rebar types of single-row and two-row are satisfactory. Seismic behavior of the specimens with two-row splice rebars seems better than that of the specimens with single-row splice rebars slightly. The results of finite element analysis indicate that the splice length of 1.2 times the anchorage length of the splice rebar can satisfy the minimum requirements. when the total tesion capacity of splice rebars increases, the capacity of shear wall specimens increase slightly correspondingly, the tention damaged area moves up and extends inwards. The capacity of shear walls can be enhanced by increasing the strength of cast-in-place concrete slightlty. Zone of compression damage expands, strength capacity's stability and deformability are affected when the axial force ratio of shear wall is large.(4) To verify the seimic behavior of shear wall with precast concrete hollow moulds and precast boundary elements, quasi-static tests of three full scale wall specimens and their numerical simulations have been carried out. The results indicate that the horizontal force and displacement curves of specimens are basically identical before the force reaches to peak point, but there are some differences after the peak point. For the crack pattern and energy dissipation, there are some differences between the specimen with precast boundary elements and specimen with cast-in-place boundary elements.(5) According to the research results, design suggestions are proposed. In engineering practice, single-row splice rebars with a minimum splice length of 1.2 times the anchorage length of the splice rebar can be used when the design axial force ratio is not grater than 0.3 for the shear walls not located near the bottom zone of structure; otherwise, double-row splice rebars with a minimum splice length of 1.5 times the anchorage length of the splice rebar are suggested, especially for the shear walls loacated near the bottom zone of a shear wall structure. Futher study for the precast boundary elements should be carried on and the scope of application of the precast boundary elements should be restricted according to research results.