Study On A Bottom-Through-Diaphragm Top-Ring Splicing Joint Connecting Square Steel Tube Column And H-Shaped Steel Beam

Beam-column joint is an indispensable part of the steel structure building system.The strength and stiffness of the joint affect the safety and reliability of the structure,and the structural form of the joint also affects the use function of the structure.Therefore,in line with the development environment of prefabricated steel structure buildings,a new type of the bottom-through-diaphragm top-ring splicing joint connecting square steel tube column and H-shaped steel beam is proposed in this paper to enrich the connection form of square steel tubular column and H-type steel beam joints.In this paper,the basic specimen is designed,and the finite element software ABAQUS was used to study the mechanical properties of specimens under unidirectional static loading and low-cycle cyclic loading,as well as the effects of different parameters on energy dissipation capacity and load carrying capacity.The following conclusions were drawn:(1)This new joint realizes the plastic hinge outward shift,which can avoid the brittle failure of the beam end.(2)The slippage of the high-strength bolt and the bulging deformation of the cover plate were serious when the specimen was damaged.In the splicing area of the joint,one side of the flange cover plate is bolted,while the other side is welded to the beam flange.While the welding provides sufficient stiffness,slippage of high-strength bolts also makes the energy dissipation capacity of the joint point play better.(3)Under the action of static load,the thickness of the cover plate in the splicing area has the greatest influence on the bearing capacity of the joints,followed by the width of the cover plate,the length of the side weld and the length of the cantilever section have less influence on the bearing capacity of the joints.(3)Under low cycle load,joints are the main deformation of the upper and lower flange cover plate,the joining together of hysteresis curve are relatively full,indicate that the node has good mechanical properties and energy dissipation properties,skeleton curve about the origin of coordinates rotation symmetry,that the combination of the ‘outer ring plate – through diaphragm' satisfy the mechanical properties under tension and compression.(4)Combined with the parameter analysis,the Suggestions for the application in practical engineering are given as follows: The minimum thickness of cover plate is 10 mm,and the width of the splicing cover shall be no less than 220 mm,and the number of bolts on one side of the spliced cover plate is set at 8 to 10;increasing the hole size of the bolt to a certain extent can increase the rotation capacity of the bolt and thus better energy consumption;side of the weld seam length not less than 150mm;outside the outer ring plate type is not recommended to choose the ring plate.