The Research On Load-Bearing Performance Of Protal Frame And Its End-Plate Connection Based On Semi-Rigidity

As the typical representation of light-weight steel structure, portal frame is being widely adopted in single-story industrial plants and civil architectures. At present,design of portal frame is performed in terms of rigid joint connection hypothesis, and the effects of semi-rigid feature of end-plate connection on erformance of portal frame are not considered. Semi-rigid connection affects not only load-bearing performance of joint itself but also internal force and displacement of general portal frame structure.According to these problems, some reasonable suggestions are proposed in present study, but they are not comprehensive when it comes to how to take consideration of the effect of semi-rigid connection on structure performance during process of structural design.Aimed at the point, the haracteristics of portal frame are discussed and studied.At first, In this paper, the design methods about end-plate connection of the present oversea and domestic codes are concluded systematically.Based on the contrast with domestic calculation method, it proposes design method of joint-improving based on"T style part", cites a project example, and use this method to optimize the design of the end-plate connection secondly, with the result confirming that this method not only correct, reliable,simple, feasible but also economic to the design.In succession,on the research of semi-rigid theory, the element stiffness matrix and element stiffness equation under local coordinate, and global stiffness equation finite element under global coordinate of semi-rigid connections are derived at the height of finite element theory in this paper. It also analyzes the highly nonlinearity and complex contact of the high-strength bolt end-plate connection joints with numerical simulation, in contrast with relative literature,and gets new cognition of load-bearing performance.Finally,in this paper, lots of modelings and analysis of variable section portal frame with rigid, semi-rigid and hinged joints under the different constraint conditions of column base have been carried out in ANSYS APDL language, and the effects of internal force and displacement of portal frame structure by semi-rigidity of end-plate connections. Through the analysis of results,on the two aspects of joint forms and construction measures respectively, the cognition of improving joint stiffness is obtained and it gives valuable conclusion and suggestion to construction design, also make a foundation for further study of connection performance of this kind.