Analysis of Overall Stability and Local Stability of Legs on UHV Transmission Steel Tubular Tower

The overall stability and local stability of legs on UHV transmission steel tubular tower are controlled by the slenderness ratio and the diameter-thickness ratio of steel bar respectively. 8 typical steel tubular towers with double circuit transmission lines on the same tower in 1000kV transmission project of Anhui Province-Shanghai (the 1000kV Huainan to Shanghai transmission line, the PROJECT as called hereby in this paper) are chosen to set up the finite element model of beam-bar mixed element and calculate the stress of legs under consideration of the effect of bending moment of bar end. The result shows the effect degree of bending moment of bar end to the stress of legs is be closely related to its slenderness ratio. The law between slenderness ratio and stress is obtained by calculation and analysis. The local buckling will occur when the diameter-thickness ratio of round section of steel tubular tower is beyond a limit. Basing on this analysis result and comparison between the domestic design standard and the foreign design standard, the value of diameter-thickness ratio of round section of steel tubular tower is suggested. This study result provides references and proofs for the structural optimization of UHV Transmission Steel Tubular Tower.