Study on wind-induced vibration control and life-prolonging of large-span transmission tower-line system using bidirectional gas-spring damper

Abstract

This study proposes a bidirectional gas-spring damper (BGD) to reduce excessive wind-induced vibrations and fatigue damage in large-span transmission tower-line system (LTTS), thereby extending its service life. A detailed numerical model of a LTTS is developed based on actual engineering project, the configuration parameters of BGD for wind-induced vibration control are designed, and its working principle and preliminary design method are introduced. The control performance of the BGD in mitigating wind-induced vibration responses of the LTTS is investigated, and its corresponding configuration parameters are optimized. Stress response and fatigue performance analyses are conducted for the uncontrolled and controlled LTTS, and the life-prolonging effectiveness of the dampers is quantified and discussed. Results demonstrate that the BGD achieves vibration reduction ratio similar to that of a tuned mass damper (TMD) but with a smaller stroke and wider damping frequency band. BGD’s frequency ratio is suggested to be between 0.9 and 1.0, with an initial gas pressure of 0.9 $P_0$ providing the highest vibration reduction benefits. The adopted pressure-reduced design method decreases the stiffness variation rate, addressing the rapid decline in vibration reduction effectiveness at large frequency ratios (greater than 1.0). The damper effectively reduces the stress response and enhances the fatigue resistance of structural sensitive members, overall, the TMD extends the structural fatigue life by over 60%, while the BGD achieves a life-prolonging ratio of over 80%.