Vortex-induced vibration tests of circular cylinders connected with typical joints in transmission towers

Vortex-induced vibration (VIV) tests on full-scale cylinders are undertaken to study the vibration performance of steel tubes connected with typical joints in transmission towers, including [-shaped gusset plate connection, U-shaped gusset plate connection, cross-gusset connection and the flange. Due to the asymmetric flexural stiffness for the cross section of the [-shaped or U-shaped gusset plate, VIV is only generated about the minor axis. The paper presents the relationship between the slenderness ratio and the occurrence wind speed of VIV about the minor axis. Moreover, it has been shown that VIV can occur not only in laminar flows, but also in turbulent flows, and the amplitude decreases as the turbulence intensity rises. The amplitude is affected by the wind attack angle, and drops as the wind attack angle decreases. It is revealed that for the cylinders connected with [-shaped gusset plates with the slenderness ratio of 100∼200, the value of Strouhal number ranges from 0.20 to 0.21and the reduced velocity from 5.0 to 5.5.