This study investigates the effect of spiral rod specifications on vortex-induced vibration (VIV) countermeasures through wind-tunnel tests, aiming to optimize the VIV countermeasure for steel tower members. Experimental results showed that applying two or more spiral rods with sufficient diameter was generally effective in suppressing VIV. However, its effectiveness was influenced by the helix angle of spiral rods. Therefore, VIV amplitudes of various members used in actual transmission towers were evaluated theoretically. The evaluation indicated that applying two or more spiral rods with a diameter equal to 0.08-0.13 times of the member diameter and a helix angle of 24.3-29.8˚ was effective in improving the fatigue life of various transmission tower members.
