Analysis And Research On The Global Stability Of Suspended Guyed Tower's Main Column

As the project of West-to-east Power Transmission has developed rapidly and Northwest Interconnection project has constructed quickly, the use of suspended guyed tower can greatly save the usage amount of steel compared to the common transmission tower, reduce the amount of foundation construction and shorten the construction period in the northwest where the transmission corridor is very ample.However, with the gradual increase of line voltage level, the structure bears greater load, and the requirements of strength and stiffness is higher, so the problem about the global stability of suspended guyed tower's main column is more prominent.The lattice column is constituted by a number of rods, has a complex structure and is high hype-static, so that manual calculation is difficult to achieve and the stability has always been a difficult problem. In the engineering, the approach to calculating the lattice main column's critical load is to simplify the main column lattice as a real abdominal member and consider the effect of shear deformation by the reaction in the conversion slenderness ratio. However, the related provision in the transmission line design specifications is vague and bring much inconvenience to the design of the structure. Based on the foreign Maraba- Itacaiunas 500 k V transmission line engineering, this paper has gone on the research on calculation method of the global stability of suspended guyed tower's main column, so as to make the structure meet the strength and stability requirements at the same time and ensure its safe operation.Firstly, it introduces the current study situation about suspended guyed tower at home and abroad and the dynamic about the calculation method of lattice column's global stability. In the context of the Northwest Interconnection project, the research is presented herein combined with the practical application.Secondly, it uses ANSYS to go on the nonlinear static analysis for 500 k V suspended guyed tower structure. Considering more than 40 kinds of working conditions, it analyzes the strength, the deformation and the single limb's stability of the structure to see whether they meet the requirements. And extracting the main column's end load is to prepare for the global stability analysis.Thirdly, it analyzes the precision of the calculation methods to calculate the critical load of suspended guyed tower's main column whose cross section is equal or variable, and how the main column parameters influence its critical load. It uses ANSYS to go on the main column's elastoplastic large deflection analysis to get its ultimate stable bearing capacity and the discussion on the study of practical method to calculate the main column's global stability in the engineering.Finally, it analyzes the effects of initial defects and lateral load on the main column's global stability, and introduces the method to calculate the stability as a bending member.