DeCordova Bend Dam: Ultrasonic Testing

The DeCordova Bend Dam forms the Lake Granbury Reservoir on the Brazos River southeast of Granbury, TX and was constructed between 1966 and 1969. In conjunction with other consultants, BDI performed concrete material sampling and a nondestructive evaluation (NDE) at select portions of the dam to facilitate operational and structural improvements to the dam. A portion of our NDE scope included 

• Ultrasonic Testing (UT): straight-beam ultrasonic testing was used to assess integrity of and evaluate the presence of internal flaws (defect indications) at all trunnion anchor bars and trunnion pins on the dam. This included a total of 128 trunnion anchor bars and 32 trunnion pins spread across all 16 radial gates for the dam.

This project required a diverse set of certifications and expertise, including ASNT UT certification, SPRAT rope access certification, and specialized training and custom BDI-designed equipment for ultrasonic testing at the trunnion anchor bars. BDI’s team used rope techniques to access trunnion anchor bars and trunnion pins. Test results indicated no defect indications at the trunnion anchor bars and defect indications suggestive of wear grooves at each of the trunnion pins, possibly stemming from slight rotation of the pins during repeated operation.