Detection of Microcracks in Trunnion Rods Using Ultrasonic Guided Waves
Final rept. 1 Oct 2013-30 Sep 2014
ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS INFORMATION TECHNOLOGY LAB
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Posttensioned rods are used to anchor spillway gates and transfer the forces from the reservoir pool through the gates to the spillway structures. Large tensile loads are applied to these high-strength steel rods to compress the surrounding concrete and prevent it from experiencing excessive destructive tensile forces. These rods are now experiencing ongoing failures. The Corps of Engineers is in need of reliable nondestructive testing NDT methods that are rapid, robust, and capable of detecting and quantifying defects. Methods to detect microcracks are required to be rapid because of the large number of rods that exist at some installations. Robustness is required to handle the significant variations in design, construction, and field conditions that are known to exist. Defect detection and quantification provides tracking and monitoring data important for planning and prioritizing remediation efforts or operational practices. This research to date has defined and demonstrated acoustical guided waves as a methodology to detect cracks that are orthogonal to the axis of the trunnion rods. A test method and equipment specifications have been developed as well as methods for dealing with field conditions such as anchor rods with rough cut ends.
- Civil Engineering
- Test Facilities, Equipment and Methods