Tainter Gates - What's Important and What's Practical

The condition and operation of tainter gates are crucial factors in the overall performance and safety of dams. As the major moving component on gated spillways, tainter gates require special attention. Through our experience inspecting and evaluating tainter gates, we have learned some lessons on the level of effort that should be expended on these inspections and analyses. Climbing inspections of the gates has proven to be the place where time is best spent. Learn about several significant problems on gates we discovered that would not have been discovered from more distant observations.

The level of detail of the structural analysis for a tainter gate should be determined on a case-by-case basis. Several factors including the consequences of the gate failure, the type of failure resulting from a failure of a particular member, redundant members, etc., dictate that level of effort. In many cases, a conservative simple analysis is adequate to assess the structural integrity of a tainter gate. Additionally, the timing of the analysis is important. At least a preliminary tainter gate stress analysis should be performed prior to the gate inspection to assess the critical areas of concern that need to be observed during the gate inspection. After the physical inspection is completed, the significance of any problems noted during the inspection should be evaluated in the final structural analysis and used to guide any recommendations for remedial action.

Trunnion pin friction is the issue that sparked the nation to take a closer look at tainter gates. However, through our experiences, we have found that trunnion pin friction rarely has a significant impact on the overall integrity of the gate's structural members. More significant are rust that reduce member sizes, modifications to the original design, past repairs, distorted members, and other problems that can be detected during the gate inspections. However, the most significant factor that can lead to a gate failure (as with any other steel structure) is connection distress.

Generally, a detailed physical inspection of a tainter gate combined with the appropriate structural analysis will result in an economical and adequate tainter gate evaluation. 12 pp.