Research On Mechanical Properties Of Semi-rigid Connected Steel Frame

Steel structure beam-column connection has been a key part of the design process of the steel structure, and it affects the overall performance of the steel framework. Usually in the design, the connection nodes of the frame are assumed as rigidity joints with infinite stiffness or hinge nodes with zero stiffness. Such idealized assumptions simplify the analysis and design of the steel frame, but it cannot truly reflect the structural force conditions. Since the1994American Northridge earthquake and the1995Kobe earthquake in Japan, with a large number of steel frame joints turned out to be brittle damage, then people began to focus on the steel frame joints, semi-rigid connections. It is between the rigid connection and the hinged connection, which can withstand the bending moment and also has relatively cornered. And it gradually become the consider factors that can not be ignored in the analysis and design process of steel frame.This paper systematically describes the classification criteria, the connection form, the mathematical model in the semi-rigid connected steel frame; it also specifies the characteristics of each connection and introduces the impacting connection curve (the M-θr connection curve); we can get initial stiffness of the connection and relative corner according to the curve; this paper also give the beam-column matrix and generalize analysis in one of the semi-rigid connection forms (end-plate connection with high-strength bolts). I also carry on flexible, elastic-plastic and rigid analysis in the end-plate connection, give the initial stiffness equations and do weld checking, analyze the tension of high-strength bolts, take appropriate structural measures to determine the end-plate connection detail size.In view of the above factors, I build an extended end-plate connection node model using finite element analysis software ANSYS. Considering the contact between high-strength bolts and end-plate or the contact between end-plate and the column flange, I apply the vertical displacement in the end of beam after exerting pretension in high-strength bolts, solve it and then do some analysis of the results to observe the stress distribution of the various parts. In this article I describe the influencing factors of the semi-rigid connected steel frame structure design, considering the flexible and geometric nonlinear effects of the nodes in element stiffness matrix, corrects the fixed end moments and gives a simplified calculation method in the usual design of the steel framework with semi-rigid connection. In this chapter, I also give a specific example which is a single span of three-plane framework (flush end plate connection) to introduce some specific steps about semi-rigid connection design.According to the final analysis, we can draw some useful conclusions. While concluding this subject, we also have something that has yet to be resolved, pointing out the better method to improve the theory and design of semi-rigid design. I suppose that this will be the focus research in the future. And it will further protect the structural safety and will bring immeasurable positive impact in economic terms with the applying of the semi-rigid connections.