Ultrasonic Testing of Spillway Gate Anchor Bars

BDI was contracted by the Grant County Public Utility District to evaluate the condition of spillway gate anchor bars at Priest Rapids Dam in Washington State. As a key component of the Columbia River hydroelectric system, the dam relies on these concrete embedded anchor bars to safely support and operate its spillway gates. Because the bars are embedded within concrete piers, traditional visual inspection methods were unable to adequately assess their condition.

To evaluate the condition of these embedded bars, BDI utilized SPRAT-certified rope access technicians, providing a safe and efficient solution for reaching difficult-to-access areas of the structure. Once access was established, BDI performed Ultrasonic Testing (UT) to measure potential section loss caused by corrosion, wear, and other degradation mechanisms that could impact long-term performance.

The project included testing 176 anchor bars across 22 spillway gates, with each bar evaluated at seven locations for a total of 1,232 ultrasonic measurements. The comprehensive assessment provided final results showing the location and extents of indications of condition.

The results provided GCPUD with valuable information on the condition of individual anchor bars while also identifying common areas susceptible to deterioration. These insights support more targeted inspection, maintenance, and asset management strategies, helping ensure the continued safety, reliability, and serviceability of Priest Rapids Dam and its critical role in regional hydroelectric power generation.