Post-tensioned trunnion anchor rods are widely used as the structural support of Taintergates at many dams throughout the United States. There may be hundreds of these rodsthat are used for transferring the Tainter gate forces to the monolithic structure of thedam. Previous failures have occurred in some rods whereby their post-tensioned stresslevels have unknowingly released. When this occurs a rod may no longer function asoriginally intended. Identifying rods that have experienced such failure is a majorproblem for dam operators, a safety issue, and the subject of current research.The Greenup Lock and Dam is located north of the town of Greenup, KY. Since itsoriginal construction, about 950 trunnion rod lift-off tests have been preformed tomanually determine their in-situ states of tension. In 2010, a newly developednondestructive test (NDT) utilizing Dispersive Wave Propagation was applied to 104 ofGreenup’s trunnion rods to collect data used for making preliminary computation of theirin-situ loads.This paper describes the three-fold approach to nondestructively estimating tension intrunnion rods. These approaches are based upon historical data, Dispersive WavePropagation and vibration studies, and the use of a limited number of lift-off tests forcalibration and validation. Discussions will include a derivation of the mathematicalmodel, a description of the statistical approaches applied, and a discussion of howcomputational estimates are made for a rod’s tension along with the statisticaluncertainties.
展开▼
