Research On Key Technology Of Connection Between Steel Truss Beam And Column Of Integrated Floor

With the national strong promotion of "green building" and "building industrialization",more and more prefabricated buildings appear in people's field of vision.As a natural assemblable structure,steel structure is widely used in prefabricated buildings.In the process of steel structure design,joint design,especially beam-column joint design,occupies a very important position.It is important to study the mechanical properties of beam-column joints to ensure the safety of steel frame structures under various actions.The steel truss beam is used as the main stressed member in the fabricated steel structure integrated floor system.Compared with the solid web steel beam,the truss beam has many advantages,such as less steel consumption,the construction pipeline is easy to pass through the interior of the truss beam,and can improve the indoor height of the building.The joint of truss beam and column is the key part of this kind of structure system.It is one of the key points of this structural system research.In this paper,based on the background of practical engineering,experimental research and numerical analysis are carried out on the joint form of truss beam-column bolt connection for an assembly integrated floor system.In this paper,the load transfer path,deformation characteristics,failure mode,ultimate bearing capacity and key stress parts of the beam-column joint under load are studied.The influence of the thickness parameters of the joint rib plate and end plate on the mechanical performance of the beam-column fabricated joint is studied by finite element analysis,and the appropriate value range is determined.Through the tension and compression test of the notched member and the finite element method,the influence of the local opening of the truss chord due to the installation of high strength bolts on the bearing capacity of the member and the effectiveness of the reinforcement measures adopted are analyzed.The main conclusions of this paper are as follows:(1)The truss beam-column joints studied in this paper have a clear way of force transfer,but there are many force transfer links,which is easy to cause some installation gaps.(2)The fillet weld between the rib plate and the end plate and the tensile strength of the rib plate have a great influence on the connection performance of the upper chord joint.The design of the size parameters of the joint weld and rib plate can be calculated according to the hypothetical force transfer mode with large stiffness of the end plate.The joint weld of the middle rib plate and the bearing capacity of the rib plate itself should be strengthened or the rib plates on both sides should be reduced.(3)In order to be able to bear the pressure transmitted by the chord,the widthto-thickness ratio of the ribbed plate in the compression part should be controlled to meet the need of plastic force transfer.The thickness of the end plate can be determined according to the three-sided supporting plate and the bearing capacity of the compressive strength.(4)The notched part of the truss chord considering the installation requirements should be strengthened,and the reinforcement plate should not only meet the requirements of two-way eccentric bending strength,but also meet the requirements of the extension length of force transmission.Based on the results of experimental research and finite element analysis,this paper puts forward some design suggestions for the key stress parts of the connection and the requirements for the construction of truss beam-column connections.it can provide reference for the engineering application of steel truss beam-column joints in the assembled integrated floor system.