Abstract
The steel water gate, which received variable water pressure due to gap of water level between sea and balancing reservoir, damaged in its gate lip by fatigue crack. As the measures, the damaged part was replaced with new stiff elements, and various investigate programs, including observation with microscope and measurement of stress and water level, were performed. This damage was caused by the unneutral loading on the gate lip from the ground surface. The crack growth estimation was executed with FLARP, and it is confirmed that the possibility reoccurrence of fatigue crack was removed by the measures which we had taken.
