Reflections and Conclusions

In this chapter, reflection on the discovery of gate instability mechanisms is provided. Stemming from Ishii's encounter as an undergraduate with the Wachi gate failure and his subsequent development of the theory for eccentricity instability, a framework for future analyses of other gate instabilities was established. The study of two degrees-of-freedom instabilities of long-span gates created a paradigm for mode coupling in hydraulic gate vibrations. The Folsom failure occurred with eyewitness testimony claiming to have heard and felt vibration. The path to understanding the mechanism that could produce vibration of the Folsom gate was the realization that the skinplate can be easily excited to undergo streamwise vibration. To counteract such vibration, dynamic design criteria for Tainter gates are needed. A draft formulation of dynamic guidelines for Tainter gate design is developed. We hope for feedback from those who use the guidelines to provide for the continuing improvement of the guidelines.