Dissertation
Ultrasonic detection of simulated corrosion in 1 inch diameter steel tieback rods
Washington State University
Doctor of Philosophy (PhD), Washington State University
08/2009
DOI:
https://doi.org/10.7273/000005906
Abstract
The research presented investigates the use of pulse-echo ultrasonic techniques to identify simulated corrosion in steel rods. The primary objective was to quantify loss of cross section due to corrosion of steel tieback rods in earth retention systems. Current techniques require excavation of rods for inspection; however this proposed nondestructive method utilizes the end of the rod protruding from the embankment in conjunction with an ultrasonic pulse-echo system to estimate the reduction in load capacity of the rod. An ultrasonic wave was initiated with a piezoelectric transducer coupled to the end of the rod. The same transducer converted the returning wave into an ultrasonic signal which was used to determine the physical geometry of simulated corrosion. The ultrasonic signal could identify the location of simulated corrosion on the rod using the time between the main bang and the first flaw echo. The diameter of simulated corrosion could be determined from the time between the back echo and the first trailing echo. The length of the corroded region was correlated with the ratio of the first trailing echo and the back echo. Flaw echoes from simulated corrosion could be detected for all transition angles down to 5 . A decrease in the transition angle resulted in a time delay in the arrival of the flaw echo up to 23.8 [mu]s for the 5 transition, which corresponds to 5.5 in. in steel rods. Williams all-thread commercial tieback rods were tested. Ultrasonic signals generated in Williams rods embedded in various soils showed negligible attenuation of signal amplitude. Simulated corrosion geometry, including location, diameter, and length were inspectable in 1.0 in. diameter Williams tieback rods. Testing showed that ultrasonic testing could be used detected in rod lengths up to 40 feet.
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Details
- Title
- Ultrasonic detection of simulated corrosion in 1 inch diameter steel tieback rods
- Creators
- Karl R. Olsen
- Contributors
- David Garnet Pollock (Chair)David I. McLean (Committee Member)DONALD A BENDER (Committee Member)William Franklin Cofer (Committee Member) - Washington State University, Department of Civil and Environmental Engineering
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Civil and Environmental Engineering
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 123
- Identifiers
- 99901055033501842
- Language
- English
- Resource Type
- Dissertation