The impact analysis of secondary stress on ultra-high voltage double-circuit large-span steel tubular towers

In this study, we conduct a finite element analysis on a 1000kV ultra-high voltage double-circuit steel tubular tower, investigating the characteristics of secondary stress distribution in the main materials of the tower body and its impact on overall compressive stability. Focusing on the tower foot nodes of the transmission towers, we analyze the non-linear stress distribution under the influence of secondary bending moment. Results show that the maximum bending moment occurs at the tower legs, the K-member position between upper tower sections, and the slope transition area of the tower body. Compared to rod elements, the main material stresses in these areas increase by approximately 10%, 22%, and 18%, respectively. In other places, the stress rises by about 10% to 15%. Therefore, we should consider the effects of secondary stresses on the steel main materials at specific locations during the design process.