Study On The Bolts Bearing Capacity For A New Type Of Threaded All Bolts

It is inexecutable for the square steel tubular column’s closed section form when the square steel tubular column and H-shaped steel beam are connected by the ordinary all bolts connection. In order to solve this problem, a new type of unilateral all bolts connection was presented by our research group. The nut is not needed when connecting, drilling screw hole on the steel in advance and the steel plate is connected directly in joints connection. This type of connection can not only be set to all bolts connection between rectangular steel columns and steel beams, but also can be used in all kinds of cross section of light steel screw connection.In this paper, it is first and foremost to study on the stiffness range and seismic behavior for the new type of unilateral all bolts connection. Two node experiments of H-section steel mast were designed for rectangular steel columns can’t be connected by the ordinary all bolts connection: one is H-section steel mast and H-section steel beam connected by the ordinary all bolts connection, the other is using the new type of unilateral all bolts connection. By means of two groups of specimens for low cyclic test, comparing the difference of failure mode as well as capacity, hysteretic behavior, ductility, energy dissipation capacity and stiffness degradation, etc between them.Results show that: it is within the limits of semi-rigid joint when using the new type of unilateral all bolts connection. The failure mode and all aspects of seismic performance about the two groups of specimens are similar to each other, that indicate the related methods and theories of ordinary all bolts connection can be used in research of the new type of unilateral all bolts connection which presented by our research group.After understanding the stiffness range and seismic behavior for the new type of unilateral all bolts connection, a study about the influence factors of bolt’s ultimate tensile bearing capacity when the square steel tubular column and H-shaped steel beam connected by the new type of unilateral all bolts connection was given by our research group. There are fifteen square steel tubular specimens were tested. A reliable experimental theory basis for which was prided according to the different thickness of the flitch plate. The number of connecting bolts, and the tube wall strength and square steel tube’s section size. Results show that: The material strength of the pipe wall and flitch plate have the greatest impact on the ultimate bearing capacity of the bolt, then is the steel tube column section size, the thickness of the flitch plate’s effect is relatively small while the wall thickness greater than 18 mm and the ultimate tensile strength of a single bolt decreases with the increase of the number of bolts.