Prediction and Suppression of Vortex-Induced Vibration for Steel Tubes with Bolted Joints in Tubular Transmission Towers

In this paper, a series of full-scale wind tunnel tests are conducted to study the vortex-induced vibration (VIV) of the steel tubes connected with C-shaped bolted joints. The dynamic properties of VIV responses of the steel tubes are analyzed and discussed in terms of probability density functions (PDFs) and power spectral density (PSD) functions. Based on the wind tunnel test results, a new empirical formula is derived to estimate the VIV critical wind speed of the tube with C-shaped joints, and an improved model is developed to predict the maximum VIV response of the steel tube. The proposed models are further validated through an independent wind tunnel test. In order to suppress excessive VIV responses of steel tubes, a passive vibration control approach is employed by installing a discrete cross-fin spoiler (DCFS) in various designs on the testing tubes. Key design factors of the DCFS, which are related to the VIV suppression effectiveness, are studied through wind tunnel tests, and the relatively optimal design of DCFS is recommended for VIV mitigation.