Abstract
The formulas for structural analysis on shell type flap gate are presented in many papers, but there are very few reports on the process of the analysis. It is very important to know this process for the gate design engineers to skill up his ability. In flap gate it is well known that the self-excited vibration occurs by binding the nappe oscillation and the condition for this vibration arise must be known before its construction. For this situation it is important to know the natural frequency of this gate. In this report, the process of theoretical analysis on shell type flap gate which is operated by one side or both sides, are shown and the results of the numerical calculation for this are presented also. And the method to derive the natural frequency and the virtual-mass of water moving with vibrating flap gate is proposed for analyzing the occurrence of gate vibration.
