Study On The Static Performance Of New Type H-beam To Square Tubular Column Connections With Splicing Outer Sleeve

With the booming of China’ steel housing industry, the corresponding node form has being continuously improved. However, the current quality of nodes fails to fulfill the requirements of practical engineering application due to the vague load path and limitation of field welding.According to the present situation, this paper puts forward a new type of semi-rigid node form,splicing outer sleeve joints. The nodes combine square tubular column with H-beam together as a whole through the high-strength bolt and splicing outer sleeve. It is easy to install and able to effectively avoid the defects of field welding. In addition, appropriate bearing capacity and stiffness of the joint could be ensured, load path being improved to provide a reference for the design of joints.In this paper, a study was carried out by experimental research and finite element numerical simulation on the static performance of new type H-beam to square tubular column connections with splicing outer sleeve under the monotonic static loading, including joint deformation, stress distribution, beam end displacement, rotational stiffness, ultimate bearing capacity, failure characteristics etc. The feasibility of the application was investigated and appropriate improving suggestions were proposed according to the joint structure. Finally, three existing methods were adopted to distinguish the style of joint stiffness. The research work was summarized as follows:(1) Without considering the influence of horizontal forces on plane steel frame, by monotonous symmetry static load test of approximate synchronization of two full-scale cruciform node, the performance of nodes under static loading was preliminarily studied including moment-rotation relations, mechanical characteristics, failure process, ultimate bearing capacity and strain distributing state and disciplinarian with the scope of node domain. The influence of different thickness of outer sleeve was analyzed by comparison on ultimate capacity and initial rotational stiffness of novel connections. Results of the test indicated that the node has higher capacity, better rotation ability and ductile behavior.(2)The nonlinear finite element model of node was created by ANSYS FEM. The static performance such as relationship between load versus displacement and moment versus rotation,flexural capacity and stiffness were investigated. The results of simulation and tests were compared, which showed that the simulation results were reliable.(3)In order to consider the influence of horizontal forces on plane steel frame, the finite element model of typical cruciform node was created by ANSYS. This model was under the condition of antisymmetric monotonous static loading. Besides, a parametric study was conducted based on this model to investigate the influence of various parameters on relationshipbetween moment versus rotation and failure mode of node. These parameters consisted of axial compression ratio, wall thickness of columns, steel yield stress of columns, thickness of outer sleeve, cantilever member thickness of outer sleeve, yield stress of outer sleeve, thickness of cover plate, friction coefficient and high-strength bolt pulling force. The parametric study showed that flexural capacity of node could be dominated by factors including wall thickness of columns, steel yield stress of columns, thickness of outer sleeve, cantilever member thickness of outer sleeve and yield stress of outer sleeve. Moreover, the initial stiffness was influenced by wall thickness of columns and thickness of outer sleeve. Failure modes mainly included buckling failure of column cross-section, outer sleeve and assemble beam flange. Finally, reasonable suggestions were proposed for improving node structure and design references were provided for practical engineering.(4)Common distinguished methods of joint-stiffness style were briefly introduced. Based on the method of Bjorhovde, EC3 code and method of Hasan, the stiffness of node proposed in this dissertation was classified as semi-rigid.