Experiment study on vortex-induced vibration of variable cross-section bridge tower considering alongwind and acrosswind coupling effect

• Published in: Engineering structures 2025-03, Vol.327, p.119678, Article 119678
• Main Authors: Li, Shaopeng, Wang, Peng, Wu, Yanchi, Zou, Yunfeng, Yang, Qingshan, Tian, Jingying, Zhou, Yanghao
• Format: Article
• Language: English
• Subjects: Aeroelastic response; Coupling effect; Variable cross-section bridge tower; Vortex-induced vibration; Wind tunnel experiment
• ISSN: 0141-0296
• DOI: 10.1016/j.engstruct.2025.119678

This study investigates the coupled responses between the alongwind and acrosswind directions of a variable cross-section bridge tower model through wind tunnel experiments. Uniform and two turbulent flows with four different wind directions are designed to study their influences. The results show a significant coupling effect between the alongwind and acrosswind responses, influenced by incoming flow conditions and structure damping. In uniform flow, two distinct vortex-induced vibration (VIV) regions are observed when the structural damping is low, possibly due to the variable cross-section. When coupled VIV occurs, the responses of both alongwind and acrosswind directions show a hardening non-Gaussian distribution, and the kurtosis value is close to 1.5. The increase of structural damping will weaken the coupling effect, but slightly increase the dominant frequency of the coupling. Turbulence intensity reduces the VIV effect and coupling effect but does not eliminate the coupling in galloping. In particular, the critical wind speed of galloping will decrease with the increase of turbulence intensity. The coupling effect is prominent at 0° wind direction, mainly dominated by the acrosswind direction. However, the coupling effect is weak in other wind directions and is primarily dominated by the alongwind direction. The coupling effect makes the energy transfer between the alongwind and acrosswind directions, which is crucial for designing variable cross-section high-rise buildings and tower structures susceptible to wind-induced vibration. •The phenomenon of coupled VIV and galloping are observed in the aeroelastic model experiment of bridge tower.•Due to the influence of variable cross-section of tower, there are two different VIV regions in the measured wind speed range.•The influence of structural damping and turbulence intensity on VIV, galloping and coupling effect is clear examined.•The coupling effect is dominated by the acrosswind at 0o wind direction, but dominated by alongwind at other wind directions.