Evaluating the dynamic behaviour of tall free-standing surge tanks under wind load

Surge tanks in hydro facilities are one of the key components in mitigating waterhammer impacts and guaranteeing continuous operation. Tall, free-standing surge tanks are commonly designed for small to medium sized hydro facilities in low to medium seismic zones. They are often conceptually designed based on elevated tanks and/or vertical vessels to have a sufficient strength and stability against wind and seismic loads. However, tall free-standing surge tanks may be classified as dynamically sensitive structures as regards height (H> 60 m) and natural frequency, which may amplify the design forces and reactions, and consequently, the stability requirements. Moreover, natural frequency variations regarding the fluctuation of water level during a short period of time (a cycle of tracing) may also impact on the dynamic response of the tank against dynamic wind loads. In this paper, the dynamic response of the structure will be evaluated.