Experimental Study On Mechanical Behavior Of New Type All-bolts Connections Of Concrete-filled Square Tubular Column And Steel Beam

In recent years, new type column-to-H steel beam semi-rigid connection for concrete-filled square steel tube was paid attion to by more and more researchers at home and abroad because of its superior mechanical performance. Several types of corresponding nodes which are researched more fully have been adoppted in the code or specification. Now the nodes of tubular column recommended in the specifications of "Technical specification for structures with concrete-filled rectangular steel tube members (CECS 159:2004)", can not meet both the standards on construction technology and welding quality, and can not meet the pracitcal needs of the project. Several common semi-rigid joints in practical engineering and scientific research also have their inherent advantages and limitations, but it is difficult to find the joints which have both excellent technical and economic performance. For the above reseasons it is necessary to focus on the advantages of different types of nodes and develop more types of node to expand the scope of application of the structure with concrete-filled rectangular steel tube members.From the perspective of reducing the construction difficulty and easy to architectural design, referenced to long bolts joint connecting forms, a new kind of semi-rigid joint-through column High-strength boltedΠplate joint is put forward, connecting throughΠplate and bolts, overcoming the shortcomings of field welding, its such advantage: convenient and flexible construction, Significantly improve the bearing capacity and stiffness of the joint, improve the power transmission means, enriched the form of Semi-rigid joints, provide a reference for design the joints.In this paper, steel beam that connected with two T-shape joints and twoΠ-shaped joints are tested by static loading. The destroy phenomenon of each specimen were recorded in detail,then the reasons of destroy were analyzed and we discussed the influence of the deformation of the joints on the three indices that reflect the connected ability which are ultimate load-carrying capacity, the initial rotatable stiffness, the ultimate rotatable capacity. The paper also verified the advantages and disadvantages of the new shaped joints and the feasibility of the application on the edge joint and introduced seven methods that divide the joints between beam and tube, judging theΠ-shaped joints were partially-restrained connection using three among them.Indicated by the result of the study, this partially-restrained connection overcome the shortcomings of site welding and have higher shear bearing capacity and initial rotatable stiffness. TheΠ-shaped connections and the T-shaped connecions posses enough rotatable capacity, the ultimate of the relative rotation angle were more than 0.03 radians which was suggested in the FEMA of American and behave great ductility. TheΠ-shaped connections have a clear characteristic of nolinear. The stiffness and the bearing capacity can be controlled by adjusting the thickness of the connecting plate. So it is flexible to design theΠ-shaped connections.