Gate Structures – Snatched from Failure. How Many Ways Can a Radial Gate See Single Sided Hosting?

Inspections are costly on the order of tens of thousands of dollars per year for hydraulic structure owners. Why pay for them? In this paper we will present several case studies regarding how either structural or mechanical gate failures were avoided through inspection. Examples will include gate inspections performed by HDR which found critical defects relating to single sided hoisting that could have impacted dam operations or resulted in structural failure. The inspections proved to be an important risk reduction activity that paid dividends in preventing a dam safety incident from developing or worsening. The dam industry is moving towards a more risk-based approach to dam safety. Mechanical and structural components of gates systems are critical elements and must be reliable when called upon. Good inspection data forms the basis of asset management and risk assessments. There will be discussion on how different inspection strategies fed into a successful intervention. A site walk inspection may not identify critical findings on a gate from the deck or side of the spillway. Dam gate and operational systems are considered critical life safety components, therefore, while actual examples will be presented, the location, name of the dam or the owner will not be divulged as part of the presentation. It will focus on a few incident examples, lessons learned, and showing the benefit of the inspections.