Mechanical Properties Test And Theoretical Analysis Of Composite Frame Middle Joints Of Tenon-mortise Connection

Tenon-mortise joint composite frame system is a new type of building assembly structure frame system proposed in recent two years.The structure system takes tenon-mortise joints as the center,and outsources U-shaped composite beams to maximize the role of steel and cement materials.Compared with traditional steel and reinforced concrete structures,the material consumption is less and the material cost is lower.Because there are fewer types of nodes and they are manufactured in factories,component standardization can be achieved more effectively.Traditional buildings must be based on design drawings in order to complete the production,tenon and mortise steel structure process design as long as the standard of beams and columns can be arbitrarily designed,the factory can be a large number of inventory production,can improve the building assembly rate.Moreover,the external surface of tenon-mortise joint area is simple in structure,convenient in construction,good in integrity,light in weight,low in cost,and meets the requirements of sustainable development in the field of assembly construction.It is also conducive to the realization of industrial standardization and housing industrialization.At present,the research on tenon-mortise connection composite frame structure is just beginning.On the premise of drawing lessons from the existing research results on concrete filled steel tube composite structure,there is still a lot of work to be done,especially on the mechanical properties of tenon-mortise connection composite frame joints and new wrapped U-shaped steel-concrete composite beams.In this paper,the performance of column joints in tenon-mortise connection composite frame is analyzed and studied through unidirectional static test and finite element simulation.The specific work is as follows:(1)The research status and application of concrete filled steel tubular(CFST)structures at home and abroad are summarized,and the construction and advantages of tenon-mortise joints in composite frames are introduced in detail.(2)In this paper,unidirectional static test is carried out on four joint specimens of tenon-mortise joint composite frame.The deformation characteristics and stress changes of joint specimens during the whole test process are observed.The influence of the height of composite beam and the area of reinforcement in the beam on the failure mode,bearing capacity,ductility and stiffness of joint is analyzed.The straindistribution of key parts on the surface of joint beam-column is obtained.The load-displacement curves and bending moment-rotation curves of each specimen under unidirectional loads are plotted.(3)Through ABAQUS finite element analysis software,the bearing capacity of column joints in tenon-mortise joint composite frame is modeled and analyzed by three-dimensional finite element method.The determination of material constitutive relationship,contact setting,mesh division and boundary conditions in finite element model are introduced in detail.The results of finite element simulation are compared with the corresponding test results.(4)This paper summarizes the calculation methods of shear capacity of concrete filled steel tubular beam-column joints by scholars at home and abroad,and puts forward the calculation formula of shear capacity of tenon-mortise joints.