Abstract: This study examines the phenomenon of weak climbing vibration during hydrodynamic gate closing and its effect on gate vibration through an experiment on a 1:25-scale hydroelastic plane gate model for the Batang hydropower station. We control the weak gate vibrations by changing the upstream water stage, observe time variations in local stress at different locations of the gate and in its overall acceleration and displacement during gate closing after weak climbing vibration starts, and examine the characteristics of gate vibrations. The results show that 1) weak climbing vibration does not modify the overall vibration modes of the gate, though it can increase the energy of vertical vibration acceleration by 2.6 times. 2) The gate’s vertical vibration displacement is about 11 times that of the non-climbing vibration case, with its mean square deviation amplitude beyond the standard, indicating a serious vibration that may produce adverse effects on the gate and its connection structures. 3) Weak climbing vibration has the greatest effect on the measuring point No.15 located directly below the lifting lug and could tear the lug under high water head conditions. A roughly 10-time increase in the dominant frequency of stress can be observed at this point, and the local forced vibration of the gate switches to the state of periodic vibration. Thus, to avoid structure damage, it is necessary to strengthen the upper part of the main longitudinal beam of the gate and the lifting lug, which are both greatly affected by climbing vibration.

Key words: gate vibration, climbing vibration, plane gate, hydroelastic model, displacement, stress