Risk assessment and functional check of components at gated weirs and outlet works

Gated spillway weirs and gates located at outlet works play a major role in guaranteeing operational safety. They are commonly designed to operate for decades, but periodic checks relating to structural and functional stability must be carried out. These checks should include not only individual components, but the whole system, including the set of components guaranteeing functionality. The average age of dams and weirs in Italy is more than 70 years, and gate structures can be of a similar age; in other countries with a long history of hydro development, dams and gated weirs may be 100 years old. This paper describes a method to help guarantee gate functionality based on failure mode event analysis, and the set-up of safety functions for various components.