| In recent years,the development of China’s construction industry ushered in structural adjustment and industrial upgrading,and the construction industry practitioners increased research investment in prefabricated buildings with the goal of housing industrialization and construction industrialization.The prefabricated concrete structure is the most popular among the construction workers,and it is widely used.The structural system adopts the method of casting and prefabricating the important load-bearing components such as beams,slabs and columns in the factory,and only connecting the components on site.The connection mode of precast concrete beam and precast concrete column is divided into dry connection and wet connection.Wet connection is widely used in engineering,and dry connection construction is more convenient.In this paper,referring to the design idea of dry connection node form,and the existing research results of prefabricated concrete beam column joints in the United States and Japan,in order to further study the advantages and disadvantages of this type of joints,four fully assembled concrete frame beam column joints are designed,supplement the vacancy of domestic research on this kind of RCS node.Through the quasistatic test and finite element analysis of the joints,the seismic performance and stress mechanism of the fully assembled concrete joints are studied.The main research contents are as follows:The quasi-static test of four precast concrete joint members with constant axial force at the end of column is carried out.The design variables are the thickness of face plate and the height of steel hoop.By analyzing the data,the ultimate bearing capacity,ductility and equivalent viscous damping coefficient of precast concrete joints are obtained,and the influence of design variables on seismic performance of precast concrete joints is studied.The test results show that: increasing the thickness of the face plate can effectively improve the peak bearing capacity of the joint,slow down the degradation rate of the stiffness and bearing capacity index,but the ductility of the joint decreases with the increase of the thickness of the face plate;increasing the height of the steel hoop plate can effectively improve the seismic performance of the fully fabricated concrete joint.Through the analysis of the stress mechanism of the joint,it is concluded that the failure mode of the joint can be divided into two types,namely bearing failure and shear failure.To judge the type of failure mode,it is necessary to comprehensively consider the failure forms of the internal and external elements.According to the results of the test analysis,it is judged that the specimens in this paper are shear failure.On this basis,the calculation formula of the joint is derived,and the calculation formula of the shear capacity of the joint in the American design guide is improved to supplement the value of the effective width of the concrete in the outer core area.The full assembly concrete frame joint test pieces designed in this paper are simulated by finite element software.The stress performance of the joints is fully understood by comparing the skeleton curves and cloud graphs.Based on the finite element model,other parameters are analyzed,which provides a way for the subsequent research of the node. |
