Analysis On The Dual-angle Cross Combined Section

As the load effecting on steel transmission tower is becoming greater and greater, only using the existing single angle steel can’t meet the require-ments.Therefore, adopting the dual-angle cross combined section becomes a development direction. However, the existing design code for steel structures just simply made demands of this kind of components, which did not quite perfectly make guidance in this kind of component’s design.This paper extensively summaries predecessors’ research in this field, it also described theory of axial compression stability of steel structures and local stability systematically. Based on this, in this paper, the dual-angle cross combined section bending instability in the actual work condition are analyzed, also limit of the filling plate space and the local buckling in the practical engineering experiment had been to do some analysis. Combining with finite element numerical simulation, the influence of the plate type, plate space and plate thickness of cross section was summarized.First of all, based on predecessors’ research,dual-angle cross combined section’s two extreme cases of bent instability in the actual work condition is proposed in this paper, which are as follows:(a) Two angles work independently;(b)Two angles as a whole. And according to the two extreme cases,this paper puts forward the concept of plane conformity degree.Secondly,based on the prerequisite that the overall instability of single Angle between filling plate in the cross section is not ahead of the whole, the preliminary theory analysis of the limit of the filling plate space of component has been carried on, finding that under the condition of uniform stress,the compression member’s filling plate spacing d ≤40i can meet the requirements.Then, basing on the analysis of section characteristics of dual-angle cross combined section and single Angle, combining with Angle’s local buckling theory,a engineering example shows that it need to pay special attention to the limit of the width-to-thickness ratio of angle steel.Subsequently, benchmarking with plane conformity degree, and combining with finite element numerical simulation, the influence of the plate type, plate space and plate thickness of cross section on the actual bending instability state of the dual-angle cross combined section is analyzed, finding that dual-angle cross combined section with the cross type filling plate can be designed as the solid-web component when d ≤40i,while the line-styled filling plate can’t. When filling plate thickness is 0.5 to 2 times of angle steel flange plate thickness, component can be designed as the solid-web component.Finally in this paper, the further research direction of the cross section of the dual-angle cross combined section is put forward, also some prospects and suggestions for future research analysis are provided.