Design And Mechanical Performance Analysis Of Beam-column Joints For Precast Assembled Steel Structure

At present,weld joints are commonly used in China to connect steel structural beams and columns,called welded joints.This node has strict requirements on the welding technician's technology and the climatic conditions of the construction site.At the same time,the welding node will increase its safety hazard,and will increase the cost of inspection in the project;and the transportation cost of large components formed by welding is high.At present,the most advanced technology for housing industrialization in the world is the assembly node.The assembly node breaks through the defects that must be connected to the whole through welding components.It can produce standardized connection products in the factory,replacing the current welding nodes,which can greatly reduce the cost of the system and play a huge role in the energy conservation and environmental protection of steel structures.The beam-column rigid connection joints studied in this paper are composed of steel columns and cantilever beams welded with them,steel frame beams,beam flange splice plates,beam web splice plates and high-strength bolts.The cantilever beams are arranged in the middle of the steel column,and first,the cantilever beam and the steel column are welded in the factory.After the component is in place,the upper flange of the beam,the lower flange of the beam and the web of the beam are all connected by high-strength bolts.This connection method breaks through the defects of poor ductility of welding,high requirements on climate,welder technology and brittle cracks on the construction site,and has the advantages of environmental protection,strong deformation ability,fast construction speed and good construction quality.The main research contents and results of this paper are as follows:(1)Node design.By comparing the advantages and disadvantages of the four design methods,such as equal-strength design method,precise design method,simplified design method and practical design method,the static strength calculation is carried out on the node by the equal-strength design method,and the number of high-strength bolts and the size of the connecting plate are Design.(2)Numerical simulation and calculation.The finite element software ABAQUS was used to establish the beam-column joint model of fabricated steel structure.The seismic performance of the fabricated joints under monotonic loading and low-cycle repeated loading was studied and compared.(3)Sensitivity analysis of node design parameters.The influence law of the thickness and width of the web connecting plate,the thickness of the flange connecting plate,the length of the cantilever beam and the length of the flange splice plate are studied.Through five different combinations and 18 numerical analysis models,the effects of the load-displacement curve,hysteretic behavior,ductility and energy dissipation capacity,failure mode and bearing capacity on the mechanical properties of the joint are studied.In this paper,the failure modes and load-displacement curves of the nodes under monotonic loads are obtained,and the failure modes and hysteretic behaviors of the nodes under cyclic loading are further analyzed.The hysteretic behavior,bearing capacity and failure modes of the nodes are presented.The reasonable value range of node design parameters has certain practical application value.